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POCUS: Vet BLUE – Clinical Integration
Abstract
This chapter describes Vet BLUE lung ultrasound signs and their clinical applications. It discusses the uses and limitations of Vet BLUE. Tissue sign is lung consolidation similar to the shred sign, but more severe. The tissue sign is complete consolidation without any aeration and thus appears a sliver (or spleen), referred to as hepatization of lung. The wedge sign represents lung infarction. This is arguably the most abnormal or severe Vet BLUE sign by representing a pie‐shaped region of vascular necrosis. The Vet BLUE regional pattern‐based pattern approach may be used for ruling in (specificity) and ruling out (sensitivity) respiratory and nonrespiratory look‐alike causes. The chapter discusses the monitoring applications for Vet BLUE, including left‐sided congestive heart failure, pulmonary hypertension, pneumonias, and nodular disease. It also provides some case examples of Vet BLUE advantage over thoracic radiography.
Background
Human records describe pulmonary edema as a life-threatening complication of electric shock. Successful management requires prompt recognition and intensive care. However, in companion animals, electrocutions are rarely reported, even though domestic environments are full of electrical devices and there is always the possibility of accidental injury. Therefore, it is important for veterinarians to know more about this condition in order to achieve successful patient outcomes.
Case presentation
A 3-month-old male Labrador Retriever was presented with a history of transient loss of consciousness after chewing on a household electrical cord. On admission, the puppy showed an orthopneic position with moderate respiratory distress. Supplemental oxygen via nasal catheter was provided, but the patient showed marked worsening of respiratory status. Point-of-care ultrasound exams suggested neurogenic pulmonary edema due to electrical shock close to the central nervous system and increased B-lines without evidence of cardiac abnormalities. Mechanical ventilation of the patient was initiated using volume-controlled mode with a tidal volume of 9 to 15 ml/kg until reaching an end-tidal carbon dioxide ≤ 40 mm Hg, followed by a stepwise lung-recruitment maneuver in pressure-controlled mode with increases of the peak inspiratory pressure (15 to 20 cm H2O) and positive end-expiratory pressure (3 to 10 cm H2O) for 30 min, and return to volume-controlled mode with a tidal volume of 15 ml/kg until reaching a peripheral oxygen saturation ≥ 96%. Weaning from the ventilator was achieved in six hours, and the patient was discharged two days after admission without neurological or respiratory deficits.
Conclusions
We present a rather unusual case of a neurogenic pulmonary edema subsequent to accidental electrocution in a dog. Timely diagnosis by ultrasound and mechanical ventilation settings are described. Our case highlights that pulmonary edema should be considered a potentially life-threatening complication of electrical shock in small animal emergency and critical care medicine.
Vet BLUE, a standardized and validated rapid lung ultrasound examination, includes 9 acoustic windows: 4 transthoracic bilaterally applied named Caudodorsal, Perihilar, Middle, and Cranial Lung Regions plus the Diaphragmatico-Hepatic view of AFAST/TFAST. Moreover, Vet BLUE has a B-line scoring system (weak positives-1, 2, and 3 and strong positives->3 and infinite) that semiquantitate degree of alveolar-interstitial syndrome and a visual lung language for signs of consolidation (Shred Sign [air bronchogram], Tissue Sign [hepatization], Nodule Sign, and Wedge Sign [pulmonary infarction]). Using its regional, pattern-based approach, a respiratory working diagnosis may be rapidly developed point-of-care and followed serially.
Please verify if FAST should be expanded at first use - "focused assessment with sonography for trauma"?: Global FAST consists of abdominal FAST, thoracic FAST, and Vet BLUE combined as a single point-of-care ultrasound examination used as an extension of the physical examination. By applying its unbiased set of 15 data imaging points, information is gained while avoiding image interpretation errors, such as satisfaction of search error and confirmation bias error, through selective POCUS imaging. Moreover, Global FAST is used for integrating information from both cavities, rapidly screening for the Hs and Ts of cardiopulmonary resuscitation, and staging localized versus disseminated disease, helpful diagnostically and prognostically for patient work-up. By seeing a problem list, patient care is improved.
Heart disease is a common cause of morbidity and mortality in cats. Focused cardiac ultrasonography (FCU) is a useful diagnostic tool for identifying heart disease in symptomatic and asymptomatic cats when performed by trained veterinarians. When used in conjunction with other diagnostics such as physical examination, blood biomarkers, electrocardiography, Global FAST, and other point-of-care ultrasonographic examinations, FCU may improve clinical decision making and help clinicians prioritize which cats would benefit from referral for complete echocardiography and cardiac consultation. This article reviews the definition, advantages, clinical indications, limitations, training recommendations, and a protocol for FCU in cats.
Thoracic radiography (TR), the most common screening test for pulmonary metastases in dogs, can fail to detect small lesions <3 mm. Lung ultrasonography (LUS) is a widely available imaging modality capable of detecting peripheral nodules but is underutilized for this purpose. Thoracic computed tomography (CT) is the criterion standard for diagnosis of lung metastases and nodular disease but is less practical for a variety of reasons. We hypothesized that LUS would be more sensitive but less specific at detecting nodules consistent with metastatic pulmonary disease in dogs compared to TR, using CT as the criterion standard. This was a masked, single-center prospective study of 62 client-owned dogs evaluated for respiratory signs or pulmonary metastatic neoplasia screening using TR, LUS and CT. Dogs were included if metastatic pulmonary disease was a differential. All imaging modalities were scored as having nodules (yes/no) and other types of pathologic lesions were recorded. Sensitivity (Se), specificity (Sp) and positive (LR+) and negative likelihood ratios (LR-) were determined for TR and LUS.
For TR, Se and Sp were 64% and 73%, and LR + and LR- were 2.37 and 0.49, respectively. For LUS, Se and Sp were 60% and 65% and LR + and LR- were 1.71 and 0.62, respectively. The results of the study indicate that LUS had a similar Se to TR, with both modalities missing nodules when used for screening. The low Sp and LR- suggests caution should be used when assuming TR and LUS rule out the presence of nodules.
Global Focused Assessment with Sonography for Trauma (FAST) and point-of-care ultrasonography carry the potential to screen for and monitor conditions rather than traditional means without ultrasonography. Advantages include being point of care, cageside, low impact, rapid, safe, and radiation sparing, and requiring no shaving and/or minimal patient restraint. Moreover, information is real time for free fluid and soft tissue abnormalities of the abdomen, heart, and lung, which are missed or only suspected by physical examination, basic blood and urine testing, and radiography. A standardized approach with recording of patient data is integral to a successful Global FAST program.
Objective
To determine the accuracy of lung ultrasound (LUS) using the Veterinary Bedside Lung Ultrasound Examination (VetBLUE) protocol and 3‐view thoracic radiographs (TXR) compared to thoracic computed tomography (TCT) for diagnosing the presence and quantification of pulmonary contusions (PC).
Design
Prospective cohort study conducted from February 2017 to June 2018.
Setting
Private emergency and referral center.
Animals
Thirty‐two dogs having sustained motor vehicle trauma were consecutively enrolled. Three dogs were excluded from statistical analysis. All dogs survived to hospital discharge.
Interventions
Within 24 hours of sustaining trauma, dogs had LUS, TXR, and TCT performed. Using the VetBLUE protocol, LUS PC were scored according to the presence and number of B‐lines and C‐lines, indicating extravascular lung water. Thoracic radiographs and TCT were scored for PC in a similar topographical pattern to the VetBLUE protocol. Lung ultrasound and TXR were compared to “gold standard” TCT for the presence and quantification of PC.
Measurements and Main Results
On TCT, 21 of 29 (72.4%) dogs were positive and 8 of 29 (27.6%) dogs were negative for PC. When LUS was compared to TCT, 19 of 21 dogs were positive for PC (90.5% sensitivity) and 7 of 8 dogs were negative (87.5% specificity) for PC. LUS PC score correlated strongly with TCT PC score (R = 0.8, P < 0.001). When TXR was compared to TCT, 14 of 21 dogs were positive for PC (66.7% sensitivity) and 7 of 8 dogs were negative (87.5% specificity) for PC. TXR PC score correlated strongly with TCT PC score (R = 0.74, P < 0.001).
Conclusions
In this population of dogs with motor vehicle trauma, LUS had high sensitivity for diagnosis of PC when compared to “gold standard” TCT. LUS provides reliable diagnosis of PC after trauma. More patients with PC were identified with LUS than with TXR, and additional studies are warranted to determine whether this increased sensitivity is statistically significant.
Background:
The diagnosis of congestive heart failure (CHF) in cats is challenging. Point-of-care (POC) thoracic ultrasound and NT-proBNP testing are emerging tools that may aid in diagnosis.
Hypothesis/objectives:
To assess the diagnostic accuracy of POC lung ultrasound (LUS), focused cardiac ultrasound (FCU), and NT-proBNP in predicting a final diagnosis of CHF.
Animals:
Fifty-one cats in respiratory distress.
Methods:
Blood NT-proBNP, LUS, and FCU evaluating left atrial (LA) size and presence of pericardial effusion (PCEFF) were performed in all cats. Lung ultrasound findings including pleural effusion (PLEFF), number of B-lines, and sub-pleural abnormalities were noted. Medical records were evaluated for final diagnosis.
Results:
Thirty-three of 51 (65%) cats were diagnosed with CHF. Lung ultrasound and blood NT-proBNP were significant predictors of CHF in a multivariate model. The LUS criterion that maximized accuracy for CHF diagnosis was presence of >1 site strongly positive for B-lines (>3 B-lines per site), resulting in sensitivity of 78.8%, specificity of 83.3%, and area under the curve (AUC) of 0.833. Subjective LA enlargement was 97.0% sensitive and 100% specific for CHF (AUC 0.985). Presence of PCEFF also was 100% specific, but only 60.6% sensitive, for CHF (AUC 0.803). A positive blood NT-proBNP test was 93.9% sensitive and 72.2% specific for the diagnosis of CHF (AUC 0.831).
Conclusions and clinical importance:
Point-of-care diagnostic techniques of LUS, FCU, and NT-proBNP are useful to diagnose CHF in cats with respiratory distress.
Interstitial lung disease (ILD) is a major pulmonary manifestation of connective tissue disease (CTD), leading to significant morbidity and mortality. Chest high-resolution computed tomography (HRCT) is presently considered the diagnostic gold standard for pulmonary fibrosis diagnosis and quantification in the clinical arena. However, not negligible doses of ionizing radiation limit the use of HRCT, especially for serial follow-up in younger female patients. In the past decade, lung ultrasound (LUS) has been proposed to assess ILD by detecting and quantifying sonographic B-lines. Previous studies demonstrate that B-lines have a good diagnostic accuracy, especially high sensitivity, and correlate well with HRCT findings, suggesting LUS as a novel, non-invasive, and non-ionizing imaging method to be used in patients with CTD-ILD. Although preliminary data are promising, challenges and controversies still remain. For example, the mechanisms of B-line generation are not fully understood; the diagnostic accuracy and performance characteristics of LUS partially depend on the scanning scheme and scoring system used; and up-to-date B-lines cannot discriminate the early cellular inflammation from the chronic fibrotic phase in CTD-ILD. Therefore it is important for clinicians to understand the strengths and limitations of LUS in CTD-ILD patients, to maximize its value.
Background
The quantification of B-lines at lung ultrasonography is a valid tool to estimate the extravascular lung water (EVLW) in patients after major cardiac surgery. However, there is still uncertainty about the correlation between B-lines and EVLW in a general population of critically ill.
Aim
To evaluate a simplified lung ultrasonographic assessment as a tool to estimate the EVLW in critically ill patients admitted to a polyvalent intensive care unit (ICU).
Methods
Nineteen consecutive critically ill patients requiring mechanical ventilation and hemodynamic monitoring were enrolled. Lung ultrasonography and the thermodilution methodology (PiCCO system) were performed by two independent operators. The positive scan at lung ultrasound was defined by visualization of at least 3 B-lines. We then compared the number of chest areas positive for B-lines with the EVLW index obtained by the invasive procedure.
Results
A significant correlation was found between the number of lung quadrants positive for B-lines and EVLW indexed using both actual body weight (rho = 0.612 p = 0.0053) and predicted body weight (rho = 0.493 p = 0.032). Presence of more than 3 positive lung quadrants showed a good performance in identifying an EVLW index value >10 ml/kg of actual body weight(area under the ROC 0.894; 95% CI 0.668–0.987 p < 0.0001). Presence of of more than 4 positive lung quadrants indentified an EVLW index value >10 ml/kg of predicted body weight (area under the ROC 0.8; 95% CI 0.556–0.945 p = 0.0048).
Conclusion
A simplified lung ultrasound approach can by used as a reliable noninvasive bedside tool to predict EVLW in emergency and critically ill patients.
Background:
In dogs with chronic valvular heart disease (CVHD), early recognition of pulmonary edema (PE) is of paramount importance. Recent studies in dogs showed that lung ultrasound examination (LUS) is a useful technique to diagnose cardiogenic PE.
Objectives:
To describe LUS features in dogs with different stages of CVHD, and to determine its diagnostic accuracy in detecting PE using thoracic radiography as the reference standard.
Animals:
Sixty-three dogs with CVHD.
Methods:
Prospective, multicenter, cross-sectional study. Each dog underwent physical examination, echocardiography, thoracic radiography, and LUS. The LUS findings were classified as absent, rare, numerous, or confluent B-lines. Sensitivity, specificity, and positive and negative predictive values of LUS B-lines to identify PE were calculated using thoracic radiography as the reference standard.
Results:
Dogs in stage B1 had absent or rare B-lines in 14 of 15 cases (93.3%). Dogs in stage B2 had absent or rare B-lines in 16 of 18 cases (88.9%). All dogs in stage C, without radiographic signs of PE, had absent or rare B-lines. Dogs in stage C, with radiographic signs of PE, had numerous or confluent B-lines in 18 of 20 cases (90%). Lung ultrasound examination detected PE with a sensitivity of 90%, specificity of 93%, and with positive and negative predictive values of 85.7 and 95.2%, respectively.
Conclusions and clinical importance:
Lung ultrasound examination showed good diagnostic accuracy to identify cardiogenic PE and might be helpful in staging dogs with CVHD. Lung ultrasound examination should be considered as a new, noninvasive diagnostic tool for clinicians managing CVHD in dogs.
There has been an explosion of knowledge and application of clinical lung ultrasound (LUS) in the last decade. LUS has important applications in the ambulatory, emergency, and critical care settings and its deployability for immediate bedside assessment allows many acute lung conditions to be diagnosed and early interventional decisions made in a matter of minutes. This review detailed the scientific basis of LUS, the examination techniques, and summarises the current applications in several acute lung conditions. It is to be hoped that clinicians, after reviewing the evidence within this article, would see LUS as an important first-line modality in the primary evaluation of an acutely dyspneic patient.
Rapid and accurate diagnosis and treatment are paramount in the management of the critically ill. Critical care ultrasound has been widely used as an adjunct to standard clinical examination, an invaluable extension of physical examination to guide clinical decision-making at bedside. Recently, there is growing interest in the use of multi-organ point-of-care ultrasound (MOPOCUS) for the management of the critically ill, especially in the early phase of resuscitation. This article will review the role and utility of symptom-based and sign-oriented MOPOCUS in patients with undifferentiated respiratory difficulty, chest pain, or shock and how it can be performed in a timely, effective, and efficient manner.
Abstract
Background Lung ultrasound (LUS) has been successfully applied for monitoring aeration in ventilator-associated pneumonia (VAP) and to diagnose and monitor community-acquired pneumonia. However, there is as yet no scientific evidence about whether LUS reliably improves VAP diagnosis.
Methods In a multicenter prospective study of 99 patients with suspected VAP, we investigated the diagnostic performance of LUS findings of infection, subpleural consolidation, lobar consolidation, dynamic arborescent/linear air-bronchogram. We also evaluated the combination of LUS with direct microbiological examination of endotracheal aspirations (EA). Scores for LUS findings and EA were analyzed:-Clinical-LUS score (VPLUS Ventilator-associated Pneumonia Lung Ultrasound Score): ≥2 areas with subpleural consolidations 1 point; ≥1 area with dynamic arborescent/linear air-bronchogram 2 points; purulent EA 1 point.- VPLUS-EAgram: ≥2 areas with subpleural consolidations 1 points; ≥1 area with dynamic arborescent/linear air-bronchogram 2 points; purulent EA 1 point; positive direct gram stain EA examination 2 points.
Results For the diagnosis of VAP, subpleural consolidation and dynamic arborescent/linear air-bronchogram had a positive predictive value of 86% with a positive likelihood ratio of 2.8. Two dynamic linear/arborescent air-bronchograms gave a positive predictive value of 94% with a positive likelihood ratio of 7.1. The area under the curve for VPLUS-EAgram and VPLUS were respectively 0.832 and 0.743. The VPLUS-EAgram ≥3 had of 77% (58-90) specificity and 78 (65-88) sensitivity; VPLUS ≥2 had 69% (50-84) specificity and 71% (58-81) sensitivity.
Conclusions By detecting ultrasound features of infection, LUS is a reliable tool for early VAP diagnosis at the bedside.
Over the past two decades it has been increasingly recognized that whole-body ultrasound is an invaluable tool in the critically ill. In addition to offering rapid whole-body assessment, it has the advantage of being a bedside approach that is available at all times and can be repeated at will. Accordingly, it permits the immediate institution of appropriate therapeutic management. Whole-Body Ultrasound in the Critically Ill is the sequel to the author's previous books on the subject, which were first published in French in 1992 and 2002 and in English in 2004. This new volume reflects the latest state of knowledge by including a variety of improvements, revised definitions, and updated algorithms. Findings in respect of individual organs are clearly presented, and a particular feature is the in-depth coverage of the lungs, traditionally regarded as an area unsuitable for ultrasound. Throughout, the emphasis is on the practical therapeutic impact of the technique. Its value in a variety of settings, including unexplained shock, management of hemodynamic instability, acute respiratory failure (the BLUE protocol), and the critically ill neonate, is carefully explained. Interventional ultrasound and less widely recognized applications, such as mesenteric infarction, pneumoperitoneum, and intracranial hypertension, are also described. Pitfalls of the technique receive due attention. Today, whole-body ultrasound touches upon every area of critical care. This book, from the chief pioneer in the field, shows that the technique enables critical care physicians to detect therapeutically relevant signs easily and quickly. It will serve as an invaluable guide to the practice of this new form of visual medicine.
B-lines evaluated by lung ultrasound (LUS) are the sonographic sign of pulmonary congestion, a major predictor of morbidity and mortality in patients with heart failure (HF). Our aim was to assess the prognostic value of B-lines at discharge to predict rehospitalization at 6 months in patients with acute HF (AHF).
A prospective cohort of 100 patients admitted to a Cardiology Department for dyspnea and/or clinical suspicion of AHF were enrolled (mean age 70 ± 11 years). B-lines were evaluated at admission and before discharge. Subjects were followed-up for 6-months after discharge.
Mean B-lines at admission was 48 ± 48 with a statistically significant reduction before discharge (20 ± 23, p < .0001). During follow-up, 14 patients were rehospitalized for decompensated HF. The 6-month event-free survival was highest in patients with less B-lines (≤ 15) and lowest in patients with more B-lines (> 15) (log rank χ(2) 20.5, p < .0001). On multivariable analysis, B-lines > 15 before discharge (hazard ratio [HR] 11.74; 95 % confidence interval [CI] 1.30-106.16) was an independent predictor of events at 6 months.
Persistent pulmonary congestion before discharge evaluated by ultrasound strongly predicts rehospitalization for HF at 6-months. Absence or a mild degree of B-lines identify a subgroup at extremely low risk to be readmitted for HF decompensation.
To describe clinical canine patients with naturally occurring pulmonary hypertension and radiographic pulmonary alveolar infiltrates before and after treatment with sildenafil.
Ten client-owned dogs.
A retrospective analysis of dogs with echocardiographically-determined pulmonary hypertension and pulmonary alveolar infiltrates on thoracic radiographs was performed before (PRE) and after (POST) sildenafil therapy. Clinical scores, pulmonary alveolar infiltrate scores and tricuspid regurgitation gradients were analyzed PRE and POST sildenafil.
Pulmonary alveolar infiltrates associated with pulmonary hypertension developed in a diffusely patchy distribution (10/10). Sixty percent of dogs had a suspected diagnosis of interstitial pulmonary fibrosis as the etiology of pulmonary hypertension. Median PRE clinical score was 4 (range: 3-4) compared to POST score of 0 (0-2) (p = 0.005). Median alveolar infiltrate score PRE was 10 (5-12) compared to POST score of 4 (0-6) (p = 0.006). Median tricuspid regurgitation gradient PRE was 83 mmHg (57-196) compared to 55 mmHg POST (33-151) (p = 0.002).
A subset of dogs with moderate to severe pulmonary hypertension present with diffuse, patchy alveolar infiltrates consistent with non-cardiogenic pulmonary edema. The typical clinical presentation is acute dyspnea and syncope, often in conjunction with heart murmurs suggestive of valvular insufficiency. This constellation of signs may lead to an initial misdiagnosis of congestive heart failure or pneumonia; however, these dogs clinically and radiographically improve with the initiation of sildenafil.
Copyright © 2015 Elsevier B.V. All rights reserved.
Can ultrasound be of any help in the diagnosis of alveolar-interstitial syndrome? In a prospective study, we examined 250 consecutive patients in a medical intensive care unit: 121 patients with ra-diologic alveolar-interstitial syndrome (disseminated to the whole lung, n 92; localized, n 29) and 129 patients without radiologic evidence of alveolar-interstitial syndrome. The antero-lateral chest wall was examined using ultrasound. The ultrasonic feature of multiple comet-tail artifacts fanning out from the lung surface was investigated. This pattern was present all over the lung surface in 86 of 92 patients with diffuse alveolar-interstitial syndrome (sensitivity of 93.4%). It was absent or confined to the last lateral intercostal space in 120 of 129 patients with normal chest X-ray (specific-ity of 93.0%). Tomodensitometric correlations showed that the thickened sub-pleural interlobular septa, as well as ground-glass areas, two lesions present in acute pulmonary edema, were associated with the presence of the comet-tail artifact. In conclusion, presence of the comet-tail artifact allowed diagnosis of alveolar-interstitial syndrome. Lichtenstein D, Mézière G, Biderman P, Gepner A, Barré O. The comet-tail artifact: an ultrasound sign of alveolar-interstitial syndrome.
In the last 15 years, a new imaging application of sonography has emerged in the clinical arena: lung ultrasound (LUS). From its traditional assessment of pleural effusions and masses, LUS has moved towards the revolutionary approach of imaging the pulmonary parenchyma, mainly as a point-of-care technique. Although limited by the presence of air, LUS has proved to be useful in the evaluation of many different acute and chronic conditions, from cardiogenic pulmonary edema to acute lung injury, from pneumothorax to pneumonia, from interstitial lung disease to pulmonary infarctions and contusions. It is especially valuable since it is a relatively easy-to-learn application of ultrasound, less technically demanding than other sonographic examinations. It is quick to perform, portable, repeatable, non-ionizing, independent from specific acoustic windows, and therefore suitable for a meaningful evaluation in many different settings, both inpatient and outpatient, in both acute and chronic conditions.
In the next few years, point-of-care LUS is likely to become increasingly important in many different clinical settings, from the emergency department to the intensive care unit, from cardiology to pulmonology and nephrology wards.
To evaluate the feasibility of CT pulmonary angiography for identification of naturally occurring pulmonary thromboembolism in dogs using predefined diagnostic criteria and to assess the ability of echocardiography, cardiac troponins, D-dimers and kaolin-activated thromboelastography to predict the presence of pulmonary thromboembolism in dogs.
Twelve dogs with immune-mediated haemolytic anaemia and evidence of respiratory distress were prospectively evaluated. Dogs were sedated immediately before CT pulmonary angiography using intravenous butorphanol. Spiral CT pulmonary angiography was performed with a 16 detector-row CT scanner using a pressure injector to infuse contrast media through peripheral intravenous catheters. Pulmonary thromboembolism was diagnosed using predefined criteria. Contemporaneous tests included echocardiography, arterial blood gas analysis, kaolin-activated thromboelastography, D-dimers and cardiac troponins.
Based on predefined criteria, four dogs were classified as pulmonary thromboembolism positive, three dogs were suspected to have pulmonary thromboembolism and the remaining five dogs had negative scans. The four dogs identified with pulmonary thromboembolism all had discrete filling defects in main or lobar pulmonary arteries. None of the contemporaneous tests was discriminant for pulmonary thromboembolism diagnosis, although the small sample size was limiting.
CT pulmonary angiography can be successfully performed in dogs under sedation, even in at-risk patients with respiratory distress and can both confirm and rule out pulmonary thromboembolism in dogs.
Presenting signs and symptoms of pulmonary embolism (PE) are non-specific, favoring a large use of second-line diagnostic tests such as multi-detector computed tomography pulmonary angiography (MCTPA), thus exposing patients to high-dose radiation and to potential serious complications. We investigated the diagnostic performance of multiorgan ultrasonography (lung, heart and leg veins ultrasonography) and if multiorgan ultrasonography combined to Wells score and D-dimer could safely reduce MCTPA tests.
Consecutive adult patients suspected of PE and with a Wells score >4 or a positive D-dimer were prospectively enrolled in three emergency departments. Final diagnosis was obtained with MCTPA. Multiorgan ultrasonography was performed before MCTPA and considered diagnostic for PE if one or more subpleural infarcts, right ventricular dilatation or deep vein thrombosis were detected. If multiorgan ultrasonography was negative for PE, an alternative ultrasonography diagnosis was searched for. Accuracies of each single-organ and multiorgan ultrasonography were calculated.
PE was diagnosed in 110 (30.8%) out of 357 enrolled patients. Multiorgan ultrasonography yielded a sensitivity of 90% and a specificity of 86.2%, lung ultrasonography of 60.9% and 95.9%, heart ultrasonography of 32.7% and 90.9% and vein ultrasonography of 52.7% and 97.6% respectively. Among the 132 (37%) patients with multiorgan ultrasonography negative for PE plus an alternative ultrasonographic diagnosis or plus a negative D-dimer, no patients had PE as final diagnosis.
Multiorgan ultrasonography is more sensitive than single-organ ultrasonography, increases the accuracy of clinical pre-test probability estimation in patients with suspected PE and may safely reduce the MCTPA burden. (ClinicalTrials.gov number, NCT01635257).
The estimation of extra-vascular lung water (EVLW) is an essential component in the assessment of critically ill patients. EVLW is independently associated with mortality and its manipulation has been shown to improve outcome. Accurate assessment of lung water is possible with CT and MR imaging but these are impractical for real-time measurement in sick patients and have been superseded by single thermal dilution techniques. While useful, single thermo-dilution requires repeated calibration and is prone to error, suggesting a need for other monitoring methods. Traditionally the lung was not thought amenable to ultrasound examination owing to the high acoustic impedance of air; however, the identification of artefacts in diseased lung has led to increased use of ultrasound as a point of care investigation for both diagnosis and to monitor response to interventions. Following the initial description of B-lines in association with increased lung water, accumulating evidence has shown that they are a useful and responsive measure of the presence and dynamic changes in EVLW. Animal models have confirmed a correlation with lung gravimetry and the utility of B-lines has been demonstrated in many clinical situations and correlated against other established measures of EVLW. With increasing availability and expertise the role of ultrasound in estimating EVLW should be embedded in clinical practice and incorporated into clinical algorithms to aid decision making. This review looks at the evidence for ultrasound as a valid, easy to use, non-invasive point of care investigation to assess EVLW.
The previous chapters dealt with more or less usual fields. We now go deeper within this vital organ that has been slightly
overlooked by the academics, demonstrating that the diagnosis of pleural effusion or alveolar disorders was just an appetizer.
If lung ultrasound is a raison d’être of critical ultrasound, the potential of interstitial syndrome is the raison d’être
of lung ultrasound. Based on artifact analysis, it changes the approach to the critically ill. The lung was reputed to be
inaccessible to ultrasound mainly because of the artifacts, which were qualified as indesirable [ 1, 2]. Therefore, the physician
was not ready for making diagnoses based on artifacts. Similarly, when we began to define the field of critical ultrasound,
we saw at the thoracic area various kinds of fog, snow, and parasites. We could have chosen to be resigned to this like the
whole community but decided to persist. This was a vital organ after all. Little by little, we wondered whether these parasites,
sometimes horizontal, sometimes vertical, could not be a language? Perhaps it was a simple language that we just did not understand. This initiated a work of observation, assessment, classification,
and, above all, of endless submissions.
Objective:
To evaluate the diagnostic accuracy of radiographically derived measurements of vertebral heart score (VHS) and sphericity index (SI) in the detection of pericardial effusion (PE) in dogs.
Design:
Retrospective case-control study. Animals-51 dogs with PE associated with various cardiac disorders, 50 dogs with left- or right-sided cardiac disorders without PE, 50 dogs with bilateral cardiac disorders without PE, and 50 healthy dogs.
Procedures:
Measurements of VHS on lateral (lateral VHS) and ventrodorsal (ventrodorsal VHS) radiographs, SI on lateral (lateral SI) and ventrodorsal (ventrodorsal SI) radiographs, and global SI (mean of lateral SI and ventrodorsal SI) were obtained. Receiver operating characteristic curves were calculated to evaluate the diagnostic accuracy of the radiographic indexes at differentiating dogs with PE from those with other cardiac disorders without PE.
Results:
Measurements of lateral and ventrodorsal VHS were significantly higher in dogs with PE, compared with values for all dogs without PE. Measurements of lateral, ventrodorsal, and global SI were significantly lower in dogs with PE, compared with values for all dogs without PE. Cutoff values of > 11.9, > 12.3, and ≤ 1.17 for lateral VHS, ventrodorsal VHS, and global SI, respectively, were the most accurate radiographic indexes for identifying dogs with PE.
Conclusions and clinical relevance:
Cardiac silhouettes of dogs with PE were larger and more rounded, compared with those of dogs with other cardiac disorders without PE. Objective radiographic indexes of cardiac size and roundness were only moderately accurate at distinguishing dogs with PE from dogs with other cardiac disorders without PE.
To investigate the correlation between ultrasound (US) B-lines and high-resolution computed tomography (HRCT) findings in the assessment of pulmonary fibrosis (PF) in patients with connective tissue disorders (CTD).
Thirty-four patients with a diagnosis of CTD were included. Each patient underwent clinical examination, pulmonary function test (PFT), chest HRCT, and lung US by an experienced radiologist or rheumatologist. A second rheumatologist carried out US examinations to assess interobserver agreement. In each patient, US B-line lung assessment including 50 intercostal spaces (IS) was performed. For the anterior and lateral chest, the IS were the second to the fifth along the parasternal, mid-clavicular, anterior axillary, and medial axillary lines (the left fifth IS of the anterior and lateral chest was not performed because of the presence of the heart, which limits lung visualization). For the posterior chest, the IS assessed were the seventh to the eighth along the posterior-axillary and subscapular lines. The second to eighth IS were assessed in the paravertebral line. In each IS, the number of US B-lines under the transducer was recorded, summed, and graded according to the following semiquantitative scoring: grade 0 = normal (< 10 B-lines); grade 1 = mild (11 to 20 B-lines); grade 2 = moderate (21 to 50 B-lines); and grade 3 = marked (> 50 B-lines).
A total of 1700 IS in 34 patients were assessed. A significant linear correlation was found between the US score and the HRCT score (p < 0.001; correlation coefficient ρ = 0.875). A positive correlation was found between US B-line assessments and values of DLCO (p = 0.014). Both κ values and overall percentages of interobserver agreement showed excellent agreement.
Our study demonstrates that US B-line assessment may be a useful and reliable additional imaging method in the evaluation of PF in patients with CTD.
Objective:
We studied an ultrasound sign, the fleeting appearance of a lung pattern (lung sliding or pathologic comet-tail artifacts) replacing a pneumothorax pattern (absent lung sliding plus exclusive horizontal lines) in a particular location of the chest wall. This sign was called the "lung point".
Design:
Prospective study.
Setting:
The medical ICU of a university-affiliated teaching hospital.
Patients:
The "lung point" was sought in 66 consecutive cases of proven pneumothorax analyzable using ultrasound--including 8 radio-occult cases diagnosed by means of CT and in 233 consecutive hemithoraces studied by CT and free of pneumothorax-- including 17 cases where pneumothorax was suspected.
Results:
The "lung point" was observed in 44 of 66 cases of pneumothorax (including 6 of 8 radio-occult cases) and in no case in the control group. The location of this sign roughly correlated with the radiological size of the pneumothorax. The "lung point" therefore had an overall sensitivity of 66 % (75 % in the case of radio-occult pneumothorax alone) and a specificity of 100%.
Conclusion:
The presence of a "lung point" allows positive diagnosis of pneumothorax at the bedside using ultrasound.
The purpose of this study is to provide evidence-based and expert consensus recommendations for lung ultrasound with focus on emergency and critical care settings.
A multidisciplinary panel of 28 experts from eight countries was involved. Literature was reviewed from January 1966 to June 2011. Consensus members searched multiple databases including Pubmed, Medline, OVID, Embase, and others. The process used to develop these evidence-based recommendations involved two phases: determining the level of quality of evidence and developing the recommendation. The quality of evidence is assessed by the grading of recommendation, assessment, development, and evaluation (GRADE) method. However, the GRADE system does not enforce a specific method on how the panel should reach decisions during the consensus process. Our methodology committee decided to utilize the RAND appropriateness method for panel judgment and decisions/consensus.
Seventy-three proposed statements were examined and discussed in three conferences held in Bologna, Pisa, and Rome. Each conference included two rounds of face-to-face modified Delphi technique. Anonymous panel voting followed each round. The panel did not reach an agreement and therefore did not adopt any recommendations for six statements. Weak/conditional recommendations were made for 2 statements, and strong recommendations were made for the remaining 65 statements. The statements were then recategorized and grouped to their current format. Internal and external peer-review processes took place before submission of the recommendations. Updates will occur at least every 4 years or whenever significant major changes in evidence appear.
This document reflects the overall results of the first consensus conference on "point-of-care" lung ultrasound. Statements were discussed and elaborated by experts who published the vast majority of papers on clinical use of lung ultrasound in the last 20 years. Recommendations were produced to guide implementation, development, and standardization of lung ultrasound in all relevant settings.
Over the past decade technological advances in the realm of ultrasound have allowed what was once a cumbersome and large machine to become essentially hand-held. This coupled with a greater understanding of lung sonography has revolutionized our bedside assessment of patients. Using ultrasound not as a diagnostic test, but instead as a component of the physical exam, may allow it to become the stethoscope of the 21st century.
Compact ultrasound technology has facilitated growth in point-of-care uses in many specialties. This review includes videos demonstrating the use of ultrasonography to guide central venous access, detect pneumothorax, detect evidence of hemorrhage after trauma, and screen for abdominal aortic aneurysm.
Echocardiographic prediction of congestive heart failure (CHF) in dogs has not been prospectively evaluated.
CHF can be predicted by Doppler echocardiographic (DE) variables of left ventricular (LV) filling in dogs with degenerative mitral valve disease (MVD) and dilated cardiomyopathy (DCM).
Sixty-three client-owned dogs.
Prospective clinical cohort study. Physical examination, thoracic radiography, analysis of natriuretic peptides, and transthoracic echocardiography were performed. Diagnosis of CHF was based upon clinical and radiographic findings. Presence or absence of CHF was predicted using receiver-operating characteristic (ROC) curve, multivariate logistic and stepwise regression, and best subsets analyses.
Presence of CHF secondary to MVD or DCM could best be predicted by E:isovolumic relaxation time (IVRT) (area under the ROC curve [AUC]=0.97, P<.001), respiration rate (AUC=0.94, P<.001), Diastolic Functional Class (AUC=0.93, P<.001), and a combination of Diastolic Functional Class, IVRT, and respiration rate (R2=0.80, P<.001) or Diastolic Functional Class (AUC=1.00, P<.001), respiration rate (AUC=1.00, P<.001), and E:IVRT (AUC=0.99, P<.001), and a combination of Diastolic Functional Class and E:IVRT (R2=0.94, P<.001), respectively, whereas other variables including N-terminal pro-brain natriuretic peptide, E:Ea, and E:Vp were less useful.
Various DE variables can be used to predict CHF in dogs with MVD and DCM. Determination of the clinical benefit of such variables in initiating, modulating, and assessing success of treatments for CHF needs further study.
To evaluate radiographic distribution of pulmonary edema (PE) in dogs with mitral regurgitation (MR) and investigate the association between location of radiographic findings and direction of the mitral regurgitant jet (MRJ).
Retrospective case series.
61 dogs with cardiogenic PE and MR resulting from mitral valve disease (MVD; 51 dogs), dilated cardiomyopathy (9), and hypertrophic cardiomyopathy (1).
Thoracic radiographs of dogs with Doppler echocardiographic evidence of MR were reviewed for location (diffuse, perihilar, or focal) of PE. Also, direction (central or eccentric) of the MRJ, as evaluated by Doppler color flow mapping (DCFM), and distribution (symmetric or asymmetric) of radiographic findings were evaluated.
Diffuse, perihilar, and focal increases in pulmonary opacity were observed in 11 (18.0%), 7 (11.5%), and 43 (70.5%) of 61 dogs, respectively. Radiographic evidence of asymmetric PE in a single lung lobe or 2 ipsilateral lobes was found in 21 dogs, with involvement of only the right caudal lung lobe in 17 dogs. Doppler color flow mapping of the MRJ was available for 46 dogs. Of 31 dogs with a central MRJ, 28 had radiographic findings indicative of symmetric PE. Of 15 dogs with eccentric MRJ, 11 had radiographic evidence of asymmetric PE, and all of these dogs had MVD.
In dogs with cardiogenic PE, a symmetric radiographic distribution of increased pulmonary opacity was predominantly associated with a central MRJ, whereas an asymmetric radiographic distribution was usually associated with eccentric MRJ, especially in dogs with MVD.
Objective:
To characterize lung ultrasonography (LUS) findings in dogs with a primary clinical complaint of cough.
Animals:
100 client-owned coughing dogs.
Procedures:
A standardized LUS examination was performed for all dogs to quantify the number of B lines and identify subpleural abnormalities at 4 sites on each hemithorax. The final clinical diagnosis (reference standard) was determined by medical record review, and sensitivity and specificity of LUS for the diagnosis of selected causes of cough was determined.
Results:
Common underlying causes of cough included dynamic airway collapse (n = 37), cardiogenic pulmonary edema (CPE; 12), and bronchitis (10). Compared with dogs with other causes of cough, dogs with bacterial pneumonia (n = 7) were more likely to have subpleural shred signs, whereas dogs with pulmonary neoplasia (4) were more likely to have subpleural nodule signs. Dogs with CPE had higher total B-line scores and higher numbers of LUS sites strongly positive for B lines (> 3 B lines/site) than other dogs. The LUS criteria of total B-line score ≥ 10 and presence of ≥ 2 sites strongly positive for B lines were each 92% sensitive and 94% specific for CPE diagnosis. Notably, 18% (16/88) of dogs with noncardiac causes of cough had been treated previously with diuretics because of prior CPE misdiagnosis.
Conclusions and clinical relevance:
LUS profiles in dogs with cough differed by the underlying cause. In dogs with a clinical history of cough, this imaging modality could be diagnostically useful, particularly to help exclude the possibility of underlying CPE.
Dogs with respiratory disease can develop pulmonary hypertension (PH), a comorbid condition that can impact therapy and prognosis. Without confirmation using the criterion standard of echocardiography, this complication may be missed. Point-of-care ultrasound (POCUS) is a simple, non-invasive screening test that may suggest PH. It was hypothesized that in dogs POCUS right-sided cardiac markers (R-SCM) at the subxiphoid view would predict moderate to severe PH confirmed by echocardiography. Forty-three client-owned dogs that underwent respiratory evaluation with POCUS and echocardiography were included. POCUS R-SCM evaluated in the subxiphoid view included subjective caudal vena cava distention (CVCsx), CVCsx >1 cm, gallbladder wall edema and ascites. PH was defined by tricuspid regurgitation pressure gradient (TRPG) as mild (30–49.9 mmHg), moderate (50–74.9 mmHg) or severe (>75 mmHg). POCUS subxiphoid views were blindly evaluated post hoc and compared to echocardiography. Chi square test and one-way ANOVA were used to evaluate correlations between POCUS R-SCM and echocardiographic diagnosis of moderate to severe PH.
Twenty-six dogs with PH, and 17 dogs without PH, were enrolled. There was no significant difference in the presence or absence of any R-SCM between dogs with and without PH. When dogs with no PH and mild PH were grouped and compared to dogs with moderate to severe PH (i.e., dogs for which treatment for PH would be recommended), no significant differences in R-SCM were noted. POCUS R-SCM using the CVCsx view was not a sensitive screening test to identify dogs with PH in this study population.
Lung ultrasound B-lines are the sonographic pattern of partial deaeration of the lung. In patients with pulmonary edema they are detected as multiple, diffuse, and bilateral, by placing the ultrasound probe in the intercostal spaces. B-lines can be used for bedside monitoring of pulmonary decongestion, and can guide diuretic therapy. Persistent pulmonary congestion after hospitalization for acute heart failure increases the risk of being rehospitalized in the following months. Adding B-lines assessment to echocardiography in an integrated cardiopulmonary ultrasound is of great value in establishing the kind and degree of myocardial and valvular impairment, and their hemodynamic consequences as pulmonary edema.
Focused Ultrasound Techniques for the Small Animal Practitioner offers a highly practical guide to incorporating abbreviated ultrasound exams into the veterinary practice. Focused point-of-care exams are an effective way to quickly detect conditions and complications not readily apparent through the physical exam, laboratory diagnostics, or radiographic findings. Encompassing all the information needed to begin performing these techniques, Focused Ultrasound Techniques for the Small Animal Practitioner is a useful tool for improving patient outcomes in clinical practice. Covering focused exams in all body systems, the book also outlines the principles of interventional radiology, medical documentation, and the basic fundamentals of using an ultrasound machine. A companion website offers 87 video clips of AFAST, TFAST, and Vet Blue examinations with normal, abnormal, and incidental findings at www.wiley.com/go/lisciandro/ultrasound. Focused Ultrasound Techniques for the Small Animal Practitioner is an essential purchase for veterinary practitioners and specialists wanting to implement these techniques in their veterinary practice.
Despite the consensus on the role of lung and pleura ultrasound in human medicine, veteri- nary medicine questions credibility of the pulmonary evaluation in ultrasound examination, based on the analysis of artifacts in animals with clinical signs of respiratory failure and possibility of pulmonary edema diagnosis with recognition of the degree of its severity. The study was conduct- ed on 47 animals (29 dogs and 18 cats) of different breeds, age and sex. In all of animals prior to the transthoracic lung and pleura ultrasound examination (TLPUS), all animals were subjected to a clinical examination and hematological blood test as well as chest radiography examination in three projections. Ultrasound imaging of the chest in each animal was performed at designated four defined segments. TLPUS in dogs and cats based on an analysis of artifacts allows recogni- tion of pulmonary edema, to the degree comparable to chest X-ray examination. The number of depicted B-lines artifacts is proportional to the degree of pulmonary edema. These results allow to reduce the number of radiographs and allow the shortening of the diagnostic process for pa- tients in life-threatening condition.
Objective
To assess distribution of alveolar‐interstitial syndrome (AIS) detected by lung ultrasound (LUS) compared to thoracic radiographs (TXR).
Design
Prospective study.
Setting
University teaching hospital.
Animals
Seventy‐six dogs and 24 cats with acute respiratory distress or tachypnea.
Interventions
Patients underwent LUS and TXR within 6 hours. Lung ultrasound images were scored for presence and quantity of B‐lines in 4 lung quadrants (right cranial, right caudal, left cranial, left caudal). An individual LUS quadrant was scored positive if > 3 B‐lines were observed within a single intercostal space. Dorsoventral TXR were scored for presence of AIS in the same 4 quadrants. An individual TXR quadrant was scored positive if infiltrate was present in ≥ 25% of the quadrant. Medical records were evaluated for final diagnosis.
Measurements and Main Results
Quadrant‐by‐quadrant spatial agreement in assigning AIS using LUS versus TXR was fair (K = 0.24 – 0.56). Lung ultrasound scored a higher number of quadrants positive per patient (2.65 ± 1.59 vs. 2.13 ± 1.48; P = 0.012). Patterns of distribution of AIS differed significantly based on final diagnosis. Patients with left‐sided congestive heart failure were more likely to have diffuse AIS on LUS (P < 0.001) or bilateral caudal AIS on TXR (P = 0.04) while patients with noncardiac disease were more likely to have absence of AIS in all quadrants using either modality (P < 0.001). Differences in spatial distribution of AIS were also noted among disease subcategories.
Conclusions
Lung ultrasound and TXR were both useful to detect and categorize distribution of alveolar or interstitial pulmonary pathology. Spatial agreement between modalities was only fair. Overall, LUS detected a higher incidence of AIS compared to TXR. Both modalities detected differences in distribution of AIS based on final diagnosis, suggesting that a regional pattern‐based approach to thoracic imaging may prove diagnostically useful.
OBJECTIVE To determine the accuracy of a point-of-care lung ultrasonography (LUS) protocol designed to diagnose cardiogenic pulmonary edema (CPE) in dyspneic dogs and cats.
DESIGN Diagnostic test evaluation.
ANIMALS 76 dogs and 24 cats evaluated for dyspnea.
PROCEDURES Dogs and cats were evaluated by LUS; B lines were counted at 4 anatomic sites on each hemithorax. A site was scored as positive when > 3 B lines were identified. Animals with ≥ 2 positive sites identified on each hemithorax were considered positive for CPE. Medical records were evaluated to obtain a final diagnosis (reference standard) for calculation of the sensitivity and specificity of LUS and thoracic radiography for the diagnosis of CPE.
RESULTS Dogs and cats with a final diagnosis of CPE had a higher number of positive LUS sites than did those with noncardiac causes of dyspnea. Overall sensitivity and specificity of LUS for the diagnosis of CPE were 84% and 74%, respectively, and these values were similar to those of thoracic radiography (85% and 87%, respectively). Use of LUS generally led to the misdiagnosis of CPE (ie, a false-positive result) in animals with diffuse interstitial or alveolar disease. Interobserver agreement on LUS results was high (κ > 0.85).
CONCLUSIONS AND CLINICAL RELEVANCE LUS was useful for predicting CPE as the cause of dyspnea in dogs and cats, although this technique could not be used to differentiate CPE from other causes of diffuse interstitial or alveolar disease. Point-of-care LUS has promise as a diagnostic tool for dyspneic dogs and cats.
Noncardiogenic pulmonary edema is an important cause of respiratory disease in dogs and cats but few reports describe its radiographic appearance. The purpose of this retrospective case series study was to describe radiographic findings in a large cohort of dogs and cats with presumed noncardiogenic pulmonary edema and to test associations among radiographic findings versus cause of edema. Medical records were retrieved for dogs and cats with presumed noncardiogenic edema based on history, radiographic findings, and outcome. Radiographs were reviewed to assess lung pattern and distribution of the edema. Correlation with the cause of noncardiogenic pulmonary edema was evaluated with a Fisher's exact test. A total of 49 dogs and 11 cats were included. Causes for the noncardiogenic edema were airway obstruction (n = 23), direct pulmonary injury (n = 13), severe neurologic stimulation (n = 12), systemic disease (n = 6), near-drowning (n = 3), anaphylaxis (n = 2) and blood transfusion (n = 1). Mixed, symmetric, peripheral, multifocal, bilateral, and dorsal lung patterns were observed in 44 (73.3%), 46 (76.7%), 55 (91.7%), 46 (76.7%), 46 (76.7%), and 34 (57.6%) of 60 animals, respectively. When the distribution was unilateral, pulmonary infiltration involved mainly the right lung lobes (12 of 14, 85.7%). Increased pulmonary opacity was more often asymmetric, unilateral, and dorsal for postobstructive pulmonary edema compared to other types of noncardiogenic pulmonary edema, but no other significant correlations could be identified. In conclusion, noncardiogenic pulmonary edema may present with a quite variable radiographic appearance in dogs and cats.
Ultrasonography is an essential imaging modality in the ICU used to diagnose and guide the treatment of cardiopulmonary failure. Critical care ultrasonography requires that all image acquisition, image interpretation, and clinical applications of ultrasonography are personally performed by the critical care clinician at the point of care and that the information obtained is combined with the history, physical, and laboratory information. Point-of-care ultrasonography is often compartmentalized such that the clinician will focus on one body system while performing the critical care ultrasonography examination. We suggest a change from this compartmentalized approach to a systematic whole-body ultrasonography approach. The standard whole-body ultrasonography examination includes thoracic, cardiac, limited abdominal, and an evaluation for DVT. Other elements of ultrasonography are used when clinically indicated. Each of these elements is reviewed in this article and are accompanied by a link to pertinent cases from the Ultrasound Corner section of CHEST.
The use of focused ultrasound (US) for cardiopulmonary resuscitation (CPR) recently has become an important player in rapidly addressing primary causes of cardiopulmonary arrest (CPA) that would otherwise be occult or suspect. The advantages of FAST-ABCDE are the evaluation of the upper airways, additions to the heart scan, and the evaluation of the optic nerve sheath diameter (ONSD) as a marker for intracranial hypertension. This chapter highlights what the focused CPR (GFAST3) and the FAST-ABCDE exam can do and cannot do, and indications and objectives of the GFAST3 and the FAST-ABCDE exam. Next, ultrasound settings, probe preferences, and patient positioning are discussed. Focused CPR includes the combination of AFAST3, TFAST3, and Vet BLUE. The FAST-ABCDE is performed for checking airway and breathing, checking for thoracic and abdominal circulation, looking for disability, and exposure. Finally, clinical significance and implications of abnormal focused CPR and FAST-ABCDE exam findings are dealt with.
Thoracic focused assessment with sonography for trauma (TFAST) has more recently included a more comprehensive novel lung surveillance called the veterinary (Vet) bedside lung ultrasound exam (BLUE) that extends beyond the TFAST3 chest tube site (CTS). This chapter begins by briefly highlighting what a TFAST3 can do and cannot do. This is followed by brief descriptions on the indications and objectives for the TFAST3 exam. Lateral recumbency lends itself to efficiently performing four of the five TFAST3 views before moving the veterinary patient to sternal for the final opposing CTS view. The bilaterally applied CTS are used for the diagnosis of pneumothorax (PTX) because they are the highest point, the least-gravity dependent site, and on the thoracic wall where air would accumulate in PTX. The lung point should be searched for in all PTX suspects to increase sensitivity, and determine the severity of the PTX.
The development of widespread lung cancer screening programs has the potential to dramatically increase the number of thoracic computed tomography (CT) examinations performed annually in the United States, resulting in a greater number of newly detected, indeterminate solitary pulmonary nodules (SPNs). Additional imaging studies, such as fluorodeoxyglucose F 18 (FDG)-positron emission tomography (PET), have been shown to provide valuable information in the assessment of indeterminate SPNs. Newer technologies, such as contrast-enhanced dual-energy chest CT and FDG-PET/CT, also have the potential to facilitate diagnosis of potentially malignant SPNs.
Copyright © 2015 Elsevier Inc. All rights reserved.
Pulmonary edema is the most common complication of left-sided heart failure in dogs and early detection is important for effective clinical management. In people, pulmonary edema is commonly diagnosed based on transthoracic ultrasonography and detection of B line artifacts (vertical, narrow-based, well-defined hyperechoic rays arising from the pleural surface). The purpose of this study was to determine whether B line artifacts could also be useful diagnostic predictors for cardiogenic pulmonary edema in dogs. Thirty-one normal dogs and nine dogs with cardiogenic pulmonary edema were prospectively recruited. For each dog, presence or absence of cardiogenic pulmonary edema was based on physical examination, heartworm testing, thoracic radiographs, and echocardiography. A single observer performed transthoracic ultrasonography in all dogs and recorded video clips and still images for each of four quadrants in each hemithorax. Distribution, sonographic characteristics, and number of B lines per thoracic quadrant were determined and compared between groups. B lines were detected in 31% of normal dogs (mean 0.9 ± 0.3 SD per dog) and 100% of dogs with cardiogenic pulmonary edema (mean 6.2 ± 3.8 SD per dog). Artifacts were more numerous and widely distributed in dogs with congestive heart failure (P < 0.0001). In severe cases, B lines increased in number and became confluent. The locations of B line artifacts appeared consistent with locations of edema on radiographs. Findings from the current study supported the use of thoracic ultrasonography and detection of B lines as techniques for diagnosing cardiogenic pulmonary edema in dogs.
Lung ultrasound is superior to lung auscultation and supine chest radiography for many respiratory conditions in human patients. Ultrasound diagnoses are based on easily learned patterns of sonographic findings and artifacts in standardized images. By applying the wet lung (ultrasound lung rockets or B-lines, representing interstitial edema) versus dry lung (A-lines with a glide sign) concept many respiratory conditions can be diagnosed or excluded. The ultrasound probe can be used as a visual stethoscope for the evaluation of human lungs because dry artifacts (A-lines with a glide sign) predominate over wet artifacts (ultrasound lung rockets or B-lines). However, the frequency and number of wet lung ultrasound artifacts in dogs with radiographically normal lungs is unknown. Thus, the primary objective was to determine the baseline frequency and number of ultrasound lung rockets in dogs without clinical signs of respiratory disease and with radiographically normal lung findings using an 8-view novel regionally based lung ultrasound examination called Vet BLUE. Frequency of ultrasound lung rockets were statistically compared based on signalment, body condition score, investigator, and reasons for radiography. Ten left-sided heart failure dogs were similarly enrolled. Overall frequency of ultrasound lung rockets was 11% (95% confidence interval, 6–19%) in dogs without respiratory disease versus 100% (95% confidence interval, 74–100%) in those with left-sided heart failure. The low frequency and number of ultrasound lung rockets observed in dogs without respiratory disease and with radiographically normal lungs suggests that Vet BLUE will be clinically useful for the identification of canine respiratory conditions.
Objective: To estimate the relative accuracy of a thoracic focused assessment with sonography for trauma (TFAST) protocol for rapid diagnosis of pneumothorax (PTX) and other thoracic injury in traumatized dogs.
Design: Prospective case series.
Setting: Private veterinary emergency center.
Animals: One hundred and forty-five client-owned dogs evaluated within 24-hours of injury.
Interventions: Thoracic focused assessment with sonography for trauma protocol.
Measurements and Main Results: Traumatized dogs were evaluated with a conventional ultrasound (US) machine using a standardized 4-point thoracic FAST protocol before thoracic radiography (CXR) and thoracocentesis. PTX was diagnosed by the absence of the ‘glide sign,’ defined as the lack of the normal dynamic interface between lung margins gliding along the thoracic wall during respiration. Concurrent thoracic trauma was diagnosed by the presence of pleural or pericardial fluid or the presence of a ‘step sign,’ defined as an abnormal glide sign. Accuracy of TFAST was calculated relative to CXR findings.
Results: Overall sensitivity (Se), specificity (Sp), and accuracy of TFAST relative to CXR were 78.1% (95% CI; 61.5, 89.9), 93.4% (95% CI; 87.4, 97.1), and 90.0%, respectively. Se and Sp were higher in dogs with penetrating trauma (93.3%, 96.0%) and for the evaluator with the most clinical experience (95.2%, 96.0%); only Se between the most experienced compared with others was statistically significant (P<0.05). TFAST documented other concurrent thoracic injury. Median time for TFAST was 3 minutes.
Conclusions and Clinical Relevance: TFAST has the potential to rapidly diagnose PTX and other thoracic injury and guide therapy, including potentially life-saving interventions, in traumatized dogs.
In circulatory failure, fluid administration limited by lung sonography protocol uses lung ultrasound artifacts and makes sequential diagnosis of obstructive, cardiogenic, hypovolemic, and septic shock. Lung ultrasound is used along with simple cardiac and vena cava analysis. Whenever echocardiography cannot be performed, fluid administration limited by lung sonography protocol is favored because of its simplicity and could prove contributive. It is based on the presence (B profile) or the absence (A profile) of interstitial pulmonary edema. However, the latter does not represent actual alveolar edema, and transthoracic echocardiography is still used by intensivists as a pivotal hemodynamic measure. Tissue Doppler imaging facilitates the estimation of left ventricular filling pressures, whereas assessing right ventricular function is of prognostic value in states of shock due to massive pulmonary embolism and acute respiratory distress syndrome. In mechanically ventilated patients, poor acoustic windows are evident and performing transesophageal echocardiography may be necessary. Whenever noninvasive hemodynamic measures are inconclusive, in a deteriorating patient, a pulmonary artery catheter may be placed. Ultrasound is not a therapy but a guide for treatment, and physicians should aim to treat underlying pathologies. Despite its limitations, general chest ultrasound (lung and cardiac ultrasound) is a powerful diagnostic and monitoring tool reflecting an era of genuine "visual" medicine.
To compare the detection of pulmonary nodules by use of 3-view thoracic radiography and CT in dogs with confirmed neoplasia.
Prospective case series.
33 dogs of various breeds.
3 interpreters independently evaluated 3-view thoracic radiography images. The location and size of pulmonary nodules were recorded. Computed tomographic scans of the thorax were obtained and evaluated by a single interpreter. The location, size, margin, internal architecture, and density of pulmonary nodules were recorded. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated for thoracic radiography (with CT as the gold standard).
21 of 33 (64%) dogs had pulmonary nodules or masses detected on CT. Of the dogs that had positive CT findings, 17 of 21 (81%) had pulmonary nodules or masses detected on radiographs by at least 1 interpreter. Sensitivity of radiography ranged from 71% to 95%, and specificity ranged from 67% to 92%. Radiography had a positive predictive value of 83% to 94% and a negative predictive value of 65% to 89%. The 4 dogs that were negative for nodules on thoracic radiography but positive on CT were all large-breed to giant-breed dogs with osteosarcoma.
CT was more sensitive than radiography for detection of pulmonary nodules. This was particularly evident in large-breed to giant-breed dogs. Thoracic CT is recommended in large-breed to giant-breed dogs with osteosarcoma if the detection of pulmonary nodules will change treatment.
Computed tomography (CT) has become more widely available and computed radiography (CR) has replaced film-screen radiography for canine thoracic imaging in many veterinary practices. There are limited data comparing these modalities in a veterinary clinical setting to detect pulmonary nodules. We compared CT, CR, and film-screen radiography for detecting the presence, number, and characteristics of pulmonary nodules in dogs. Observer performance for a variety of experience levels was also evaluated. Twenty-one client-owned dogs with a primary neoplastic process underwent CT and CR; nine also received film-screen radiographs. Positive/negative classification by consensus agreed between the three modalities in 8/9 dogs and between CR and CT in the remaining 12. CT detected the greatest (P = 0.002) total number of nodules and no difference was seen between CR and films. The greatest number of nodules was seen in the right middle and both caudal regions, but only using CT (P < 0.0001). Significantly smaller nodules were detected with CT (P = 0.0007) and no difference in minimum size was detected between CR and films. Observer accuracy was high for all modalities; particularly for CT (90.5-100%) and for the senior radiologist (90.5-100%). CT was also characterized by the least interobserver variability. Although CT, CR, and film-screen performed similarly in determining the presence or absence of pulmonary nodules, a greater number of smaller nodules was detected with CT, and CT was associated with greater diagnostic confidence and observer accuracy and agreement.
Ultrasound interstitial syndrome is an echographic pattern of the lung characterized by the presence of multiple acoustic artifacts called "comets" or B-lines. It correlates to increase in extravascular lung water and to interstitial lung disease. From the physical and genetic point of view, the characteristics and the entity of this correlation have not yet been studied. The purpose of this study was to extrapolate past observations and demonstrate how comets or B-lines are artifactual images whose formation is linked to ultrasound interactions on discretely aerated tissues of variable density. Echographic comets were studied by scanning a wet synthetic, partially aerated polyurethane sponge (phantom). Density of the phantom in different drying phases was measured and correlated to the presence of echographic artifacts. Artifacts (comets) showed a different concentration from a completely white artifactual field to presence of rare comets. Their density correlates with porosity and geometry of the phantom. In our opinion, comets represent superficial, artifactual, density and geometry correlated phenomenon due to the acoustic permeability of a broken (collapsed) specular reflector, normally present when the phantom is dry.
Appendicular osteosarcoma (OSA) is a highly metastatic tumour in dogs. The aim of the study was to compare thoracic radiographs with thoracic computed tomography (CT) in the staging of canine appendicular OSA. In all, 39 canine patients histologically diagnosed with OSA were reviewed in the retrospective study. All dogs underwent radiographic examination as well as CT examination of the thoracic cavity. Pulmonary nodules were detected radiographically in two cases (5%), whereas the CT imaging showed that pulmonary nodules were evident in 11 cases (28%, P = 0.024). There was an improved detection of small pulmonary nodules in the lung parenchyma with CT (P = 0.021). The number of nodules in CT examination had a significant negative influence on survival time (P = 0.005). However, whether nodules were present in CT or not did not influence overall survival (P = 0.368). CT examination was superior to thoracic radiography in the screening and detection of pulmonary nodules in dogs with OSA.
To review the nonradiologist use of ultrasound (US) in the setting of emergency and critical care, the development, clinical applications, and standardization of veterinary abdominal and thoracic focused assessment with sonography for trauma (FAST) techniques.
Since the 1990s, the 4-point FAST US technique has been used for injury surveillance in people with blunt and penetrating trauma. FAST screens for free fluid in the abdominal, pleural, and pericardial cavities with high sensitivity and specificity. More recently, an extended FAST scan was developed for the rapid detection of pneumothorax. These techniques and newly created scans have been applied to other critically ill, nontraumatized, subsets of human patients. As a result, the terminology related to this field, eg, extended FAST, HHFAST, FFAST, FAFF, BOAST, SLOH, bedside US, '$ Approach,' protocols, and objectives have become convoluted despite having similar goals.
The importance of US in the setting of emergency medicine is highlighted by the fact that this diagnostic modality has become an integral part of the core curriculum for nonradiologists including the American College of Surgeons, American College of Emergency Physicians, American Board of Emergency Medicine, Society of Academic Emergency Medicine, and all United States Accreditation Council for Graduate Medical Education Emergency Medicine residency programs.
Veterinary applications of FAST techniques include an abdominal FAST technique with an abdominal FAST applied fluid scoring system, and a thoracic FAST technique. In an attempt to avoid the creation of numerous acronyms, veterinarians would be well served by making the 'T' in 'FAST' stand for 'Trauma,''Triage,' and 'Tracking.'
These veterinary FAST techniques provide an extension of the physical examination for the emergency and critical care veterinarian potentially expediting diagnosis, prompting life-saving maneuvers, and guiding patient management. Further clinical research to determine sensitivity, specificity, and accuracy for specific conditions is warranted.
B-lines (also termed ultrasound lung comets) obtained with lung ultrasound detect experimental acute lung injury (ALI) very early and before hemogasanalytic changes, with a simple, noninvasive, nonionizing and real-time method. Our aim was to estimate the correlation between B-lines number and the wet/dry ratio of the lung tissue, measured by gravimetry, in an experimental model of ALI. Seventeen Na-pentobarbital anesthetized, cannulated (central vein and carotid artery) minipigs were studied: five sham-operated animals served as controls and, in 12 animals, ALI was induced by injection of oleic acid (0.1 mL/kg) via the central venous catheter. B-lines were measured by echographic scanner in four predetermined chest scanning sites in each animal. At the end of each experiment, both lungs were dissected, weighed and dried to determine wet/dry weight ratio by gravimetry. After the injection of oleic acid, B-lines number increased over time. A significant correlation was found between the wet/dry ratio and B-lines number (r = 0.91, p < 0.001). These data suggest that in an experimental pig model of ALI/ARDS, B-lines assessed by lung ultrasound provide a simple, semiquantitative, noninvasive index of lung water accumulation, strongly correlated to invasive gravimetric assessment.
To evaluate sensitivity and specificity of echocardiography for diagnosis of cardiac masses in dogs with pericardial effusion.
Retrospective case series.
107 dogs with pericardial effusion.
Records of dogs with pericardial effusion examined at the University of California-Davis Veterinary Medical Teaching Hospital from 1985 to 2006 were reviewed. Dogs were included when echocardiography and pericardectomy or necropsy were performed. Sensitivity, specificity, and metastatic rates were calculated for various causes of pericardial effusion.
107 dogs with pericardial effusion were evaluated by surgery (n = 48 dogs), necropsy (44), or both (15). Echocardiography revealed no mass (n = 41 dogs), a right atrial (RA) mass (38), a heart base (HB) mass (23), a pericardial mass (2), an HB and an RA mass (2), and a right ventricular mass (1). Sensitivity and specificity were 82% and 100%, respectively, for detection of a cardiac mass; 82% and 99%, respectively, for detection of an RA mass; and 74% and 98%, respectively, for detection of an HB mass. Most HB masses were neuroendocrine or ectopic thyroid gland tissue, but 3 were hemangiosarcomas and 4 were mesotheliomas. Most RA masses were hemangiosarcomas, but this group also included a neuroendocrine tumor, ectopic thyroid gland tissue, mesothelioma, lymphosarcoma, and sarcoma. Metastatic rates did not differ (50% to 66%) among neoplastic causes.
Echocardiography had high sensitivity and specificity for diagnosis and differentiation of RA or HB masses in dogs with pericardial effusion. There was a high rate of metastasis for cardiac masses of all causes.