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Central venous pressure (CVP) at different positive end-expiratory pressure (PEEP) levels. a The absolute values of CVP in the responder and non-responder groups. b The change of CVP during the adjustment of PEEP
Source publication
Background:
Respiratory system elastance (ERS) is an important determinant of the responsiveness of intracranial pressure (ICP) to positive end-expiratory pressure (PEEP). However, lung elastance (EL) and chest wall elastance (ECW) were not differentiated in previous studies. We tested the hypothesis that patients with high ECW or a high ECW/ERS r...
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Background
The effects of positive end-expiratory pressure (PEEP) on lung ultrasound (LUS) patterns, and their relationship with intracranial pressure (ICP) in brain injured patients have not been completely clarified. The primary aim of this study was to assess the effect of two levels of PEEP (5 and 15 cmH 2 O) on global (LUStot) and regional (an...
Citations
... The patient in the present case presented with limb swelling and pleural effusion after the first operation due to hypoproteinemia. Prior studies have shown that an accumulation of pleural fluid causes gradual increases in thoracic pressure [25], while another study showed that this condition reduces venous return and accelerates massive blood flow reversal from the large caval system into the smaller epidural veins [25,26]. Considering these anatomical prerequisites in association with pleural effusion induced by hypoproteinemia, an increased venous pressure could lead to bleeding and hematoma formation, which extend along the posterior epidural space and compress the cervical spinal cord. ...
... The patient in the present case presented with limb swelling and pleural effusion after the first operation due to hypoproteinemia. Prior studies have shown that an accumulation of pleural fluid causes gradual increases in thoracic pressure [25], while another study showed that this condition reduces venous return and accelerates massive blood flow reversal from the large caval system into the smaller epidural veins [25,26]. Considering these anatomical prerequisites in association with pleural effusion induced by hypoproteinemia, an increased venous pressure could lead to bleeding and hematoma formation, which extend along the posterior epidural space and compress the cervical spinal cord. ...
BACKGROUND
While most complications of cervical surgery are reversible, some, such as symptomatic postoperative spinal epidural hematoma (SEH), which generally occurs within 24 h, are associated with increased morbidity and mortality. Delayed neurological dysfunction is diagnosed in cases when symptoms present > 3 d postoperatively. Owing to its rarity, the risk factors for delayed neurological dysfunction are unclear. Consequently, this condition can result in irreversible neurological deficits and serious consequences. In this paper, we present a case of postoperative SEH that developed three days after hematoma evacuation.
CASE SUMMARY
A 68-year-old man with an American Spinal Injury Association (ASIA) grade C injury was admitted to our hospital with neck pain and tetraplegia following a fall. The C3-C7 posterior laminectomy and the lateral mass screw fixation surgery were performed on the tenth day. Postoperatively, the patient showed no changes in muscle strength or ASIA grade. The patient experienced neck pain and subcutaneous swelling on the third day postoperatively, his muscle strength decreased, and his ASIA score was grade A. Magnetic resonance imaging showed hypointense signals on T1 weighted image (T1WI) and T2WI located behind the epidural space, with spinal cord compression. Emergency surgical intervention for the hematoma was performed 12 h after onset. Although hypoproteinemia and pleural effusion did not improve in the perioperative period, the patient recovered to ASIA grade C on day 30 after surgery, and was transferred to a functional rehabilitation exercise unit.
CONCLUSION
This case shows that amelioration of low blood albumin and pleural effusion is an important aspect of the perioperative management of cervical surgery. Surgery to relieve the pressure on the spinal cord should be performed as soon as possible to decrease neurological disabilities.
... Ruggieri et al. [ 100 ] Randomized controlled trial 32 patients without intracranial hypertension undergoing elective supratentorial brain tumor removal No significant differences in ICP were noticed between the traditional ventilation approach (9 mL/kg V T + ZEEP) and protective ventilation (7 mL/kg V T + PEEP 5 mmHg). Chen et al. [ 74 ] Prospective study 30 patients with SAH Lung elastance, chest wall elastance and respiratory system elastance were measured at 5 and 15 cmH 2 O PEEP. In patients with higher E CW and E CW /E RS ratio developed higher ICP values in response to PEEP. ...
... ICP and pulmonary compliance did not change in both groups. [ 62 ] Chen et al. [ 74 ] furthered the analysis of the elastic properties of the respiratory system. Pressure measurements were provided by an esophageal balloon, extrapolating respiratory system elastance (E RS ), E L , and E CW at two different PEEP levels (5 and 15 cmH 2 O) while monitoring ICP. ...
Background
Patients with acute brain injury (ABI) are a peculiar population because ABI does not only affect the brain but also other organs such as the lungs, as theorized in brain–lung crosstalk models. ABI patients often require mechanical ventilation (MV) to avoid the complications of impaired respiratory function that can follow ABI; MV should be settled with meticulousness owing to its effects on the intracranial compartment, especially regarding positive end-expiratory pressure (PEEP). This scoping review aimed to (1) describe the physiological basis and mechanisms related to the effects of PEEP in ABI; (2) examine how clinical research is conducted on this topic; (3) identify methods for setting PEEP in ABI; and (4) investigate the impact of the application of PEEP in ABI on the outcome.
Methods
The five-stage paradigm devised by Peters et al. and expanded by Arksey and O'Malley, Levac et al., and the Joanna Briggs Institute was used for methodology. We also adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension criteria. Inclusion criteria: we compiled all scientific data from peer-reviewed journals and studies that discussed the application of PEEP and its impact on intracranial pressure, cerebral perfusion pressure, and brain oxygenation in adult patients with ABI. Exclusion criteria: studies that only examined a pediatric patient group (those under the age of 18), experiments conducted solely on animals; studies without intracranial pressure and/or cerebral perfusion pressure determinations, and studies with incomplete information. Two authors searched and screened for inclusion in papers published up to July 2023 using the PubMed-indexed online database. Data were presented in narrative and tubular form.
Results
The initial search yielded 330 references on the application of PEEP in ABI, of which 36 met our inclusion criteria. PEEP has recognized beneficial effects on gas exchange, but it produces hemodynamic changes that should be predicted to avoid undesired consequences on cerebral blood flow and intracranial pressure. Moreover, the elastic properties of the lungs influence the transmission of the forces applied by MV over the brain so they should be taken into consideration. Currently, there are no specific tools that can predict the effect of PEEP on the brain, but there is an established need for a comprehensive monitoring approach for these patients, acknowledging the etiology of ABI and the measurable variables to personalize MV.
Conclusion
PEEP can be safely used in patients with ABI to improve gas exchange keeping in mind its potentially harmful effects, which can be predicted with adequate monitoring supported by bedside non-invasive neuromonitoring tools.
... Dead space reduction by replacing heat-moisture exchangers with heated-humidifiers is feasible and can set low VT without increasing PaCO 2 [65]. High PEEP has shown contradictory results about the response related to brain and lung compliance [66][67][68]. Measurement of transpulmonary pressure could not clarify which ABI patients had adverse effect on high PEEP [44]. PEEP adjustment is therefore recommended only during rigorous ICP monitoring and curve analysis if brain compliance is suspected to be low [44]. ...
Acute brain injury (ABI) covers various clinical entities that may require invasive mechanical ventilation (MV) in the intensive care unit (ICU). The goal of MV, which is to protect the lung and the brain from further injury, may be difficult to achieve in the most severe forms of lung or brain injury. This narrative review aims to address the respiratory issues and ventilator management, specific to ABI patients in the ICU.
... Our study did not demonstrate significant associations between respiratory compliance and the responses of ICP to LPV. Previous studies of lung compliance and ICP have given contradictory results [31,43,44]. Regarding patients with SAH, Chen et al. revealed that chest wall compliance, in contrast to lung or airway compliance, correlated inversely with ICP under exposure to increasing PEEP from 5 cmH 2 O to 15 cmH 2 O [43]. ...
... Previous studies of lung compliance and ICP have given contradictory results [31,43,44]. Regarding patients with SAH, Chen et al. revealed that chest wall compliance, in contrast to lung or airway compliance, correlated inversely with ICP under exposure to increasing PEEP from 5 cmH 2 O to 15 cmH 2 O [43]. In the latter study, the differences in mean ICP at the two PEEP levels were consistent with those observed in the present study, but with no interrupted events. ...
... The power analysis was based on local retrospective ICP data in parallel with clinical judgement, in combination with a previous observational study [29]. We considered an ICP change of 3 mmHg was considered as clinically significant, in accordance with previous studies [43,45]. We also thought that the results of this pilot study could inspire a future multicentre trial encompassing more rigid power analysis. ...
Introduction:
Lung protective ventilation (LPV) comprising low tidal volume (VT) and high positive end-expiratory pressure (PEEP) may compromise cerebral perfusion in acute brain injury (ABI). In patients with ABI, we investigated whether LPV is associated with increased intracranial pressure (ICP) and/or deranged cerebral autoregulation (CA), brain compensatory reserve and oxygenation.
Methods:
In a prospective, crossover study, 30 intubated ABI patients with normal ICP and no lung injury were randomly assigned to receive low VT [6 ml/kg/predicted (pbw)]/at either low (5 cmH2O) or high PEEP (12 cmH2O). Between each intervention, baseline ventilation (VT 9 ml/kg/pbw and PEEP 5 cmH2O) were resumed. The safety limit for interruption of the intervention was ICP above 22 mmHg for more than 5 min. Airway and transpulmonary pressures were continuously monitored to assess respiratory mechanics. We recorded ICP by using external ventricular drainage or a parenchymal probe. CA and brain compensatory reserve were derived from ICP waveform analysis.
Results:
We included 27 patients (intracerebral haemorrhage, traumatic brain injury, subarachnoid haemorrhage), of whom 6 reached the safety limit, which required interruption of at least one intervention. For those without intervention interruption, the ICP change from baseline to "low VT/low PEEP" and "low VT/high PEEP" were 2.2 mmHg and 2.3 mmHg, respectively, and considered clinically non-relevant. None of the interventions affected CA or oxygenation significantly. Interrupted events were associated with high baseline ICP (p < 0.001), low brain compensatory reserve (p < 0.01) and mechanical power (p < 0.05). The transpulmonary driving pressure was 5 ± 2 cmH2O in both interventions. Partial arterial pressure of carbon dioxide was kept in the range 34-36 mmHg by adjusting the respiratory rate, hence, changes in carbon dioxide were not associated with the increase in ICP.
Conclusions:
The present study found that most patients did not experience any adverse effects of LPV, neither on ICP nor CA. However, in almost a quarter of patients, the ICP rose above the safety limit for interrupting the interventions. Baseline ICP, brain compensatory reserve, and mechanical power can predict a potentially deleterious effect of LPV and can be used to personalize ventilator settings. Trial registration NCT03278769 . Registered September 12, 2017.
... The transmission of PEEP to pleural space depends on the elastance of both the lungs and chest wall [18]. It seemed that the stiffer chest wall had higher pressure transmission [19,20]. ...
... The characteristics of clinical parameters between obese and non-obese patients including mechanical ventilation and hemodynamic data paired to each ICP observation time were displayed in Table 2. Of the 30,415 observations (paired PEEP and ICP), 19,566 (64.3%) were for non-obese patients, and 10,849 (35.7%) for obese (19) 70 (17) 48 (22) Moderate 119 (19) 58 (14) 61 (27) Severe 38 (6) 23 (6) 15 (7) Cause of brain injury 0.07 Traumatic brain injury 180 (29) 129 (32) 51 (23) Intracranial Hemorrhage 169 (27) 114 (28) 55 (25) Subarachnoid Hemorrhage 81 (13) 48 (12) 33 (15) Ischemic Stroke 51 (8) 29 (7) 22 (10) Brain tumor 30 (5) 16 (4) 14 (6) Subdural Hematoma 24 (4) 18 (4) 6 (3) Others 82 (15) 53 (13) 39 (18) Categories of traumatic brain injury (n = 180) ...
... The transmission of PEEP to the pleural space depends on the relative elastance of the lung and the chest wall [18]. Compliant lung and/or stiff chest wall could make the transmission more effective, while decreased lung compliance may buffer the effect [15,19,20,26]. In the present study, the severity of lung injury was not predictive of the effect of PEEP on ICP, only the mild lung injury was statistically significant, which may reflect the inhomogeneity of lung injury or may have other confounders that we were unable to measure. ...
Background
The effect of positive end-expiratory pressure (PEEP) on intracranial pressure (ICP) had never been studied in obese patients with severe brain injury (SBI). The main aim was to evaluate the effect of PEEP on ICP in SBI patients with mechanical ventilation according to obesity status.
Methods
SBI patients admitted to the ICU with mechanical ventilation between 2014 and 2015 were included. Demographic, hemodynamic, arterial blood gas, and ventilator data at the time of the paired PEEP and ICP observations were recorded and compared between obese (body mass index ≥ 30 kg/m ² ) and non-obese SBI patients. Generalized estimating equation (GEE) model was used to assess the relationship between PEEP and ICP in obese and non-obese SBI patients, respectively.
Results
Six hundred twenty-seven SBI patients were included, 407 (65%) non-obese and 220 (35%) obese patients. A total of 30,415 paired PEEP and ICP observations were recorded in these patients, 19,566 (64.3%) for non-obese and 10,849 (35.7%) for obese. In the multivariable analysis, a statistically significant relationship between PEEP and ICP was found in obese SBI patients, but not in non-obese ones. For every cmH 2 O increase in PEEP, there was a 0.19 mmHg increase in ICP (95% CI [0.05, 0.33], P = 0.007) and a 0.15 mmHg decrease in CPP (95% CI [-0.29, -0.01], P = 0.036) in obese SBI patients after adjusting for confounders.
Conclusions
The results suggested that, contrary to non-obese SBI patients, the application of PEEP may produce an increase in ICP in obese SBI patients. However, the effect was modest and may be clinically inconsequential.
... pressure with reduced jugular venous outflow, hemodynamic instability [1][2][3][4], alveolar overdistension with consequent increase of arterial partial pressure of carbon dioxide (PaCO 2 ), resulting in reduced cerebral perfusion pressure (CPP) and higher intracranial pressure (ICP). ...
Background
The effects of positive end-expiratory pressure (PEEP) on lung ultrasound (LUS) patterns, and their relationship with intracranial pressure (ICP) in brain injured patients have not been completely clarified. The primary aim of this study was to assess the effect of two levels of PEEP (5 and 15 cmH 2 O) on global (LUStot) and regional (anterior, lateral, and posterior areas) LUS scores and their correlation with changes of invasive ICP. Secondary aims included: the evaluation of the effect of PEEP on respiratory mechanics, arterial partial pressure of carbon dioxide (PaCO 2 ) and hemodynamics; the correlation between changes in ICP and LUS as well as respiratory parameters; the identification of factors at baseline as potential predictors of ICP response to higher PEEP.
Methods
Prospective, observational study including adult mechanically ventilated patients with acute brain injury requiring invasive ICP. Total and regional LUS scores, ICP, respiratory mechanics, and arterial blood gases values were analyzed at PEEP 5 and 15 cmH 2 O.
Results
Thirty patients were included; 19 of them (63.3%) were male, with median age of 65 years [interquartile range (IQR) = 66.7–76.0]. PEEP from 5 to 15 cmH 2 O reduced LUS score in the posterior regions (LUSp, median value from 7 [5–8] to 4.5 [3.7–6], p = 0.002). Changes in ICP were significantly correlated with changes in LUStot (rho = 0.631, p = 0.0002), LUSp (rho = 0.663, p < 0.0001), respiratory system compliance (rho = − 0.599, p < 0.0001), mean arterial pressure (rho = − 0.833, p < 0.0001) and PaCO 2 (rho = 0.819, p < 0.0001). Baseline LUStot score predicted the increase of ICP with PEEP.
Conclusions
LUS-together with the evaluation of respiratory and clinical variables-can assist the clinicians in the bedside assessment and prediction of the effect of PEEP on ICP in patients with acute brain injury.
... Brain-lung interaction in traumatic brain injury with TBI and ARDS, it was reported that an increase in PEEP up to 15 cm H 2 O resulted in an increase in oxygen pressure and saturation in brain tissue without an increase in ICP or a decrease in cerebral perfusion pressure (CPP) [59]. Similarly, a study found that the effect of PEEP on ICP was more profound in patients with higher elastance chest walls [60]. Nevertheless, PEEP can alter CPP in hypovolemic conditions [57], which seems to indicate that an increase in PEEP can be safely applied to impart beneficial brain effects in brain-injured ARDS patients as long as they are normovolemic with high lung elastance and low chest wall elastance. ...
The brain-lung interaction can seriously affect patients with traumatic brain injury, triggering a vicious cycle that worsens patient prognosis. Although the mechanisms of the interaction are not fully elucidated, several hypotheses, notably the "blast injury" theory or "double hit" model, have been proposed and constitute the basis of its development and progression. The brain and lungs strongly interact via complex pathways from the brain to the lungs but also from the lungs to the brain. The main pulmonary disorders that occur after brain injuries are neurogenic pulmonary edema, acute respiratory distress syndrome, and ventilator-associated pneumonia, and the principal brain disorders after lung injuries include brain hypoxia and intracranial hypertension. All of these conditions are key considerations for management therapies after traumatic brain injury and need exceptional case-by-case monitoring to avoid neurological or pulmonary complications. This review aims to describe the history, pathophysiology, risk factors, characteristics, and complications of brain-lung and lung-brain interactions and the impact of different old and recent modalities of treatment in the context of traumatic brain injury.
... Besides proper arterial pressure management, ventilation has a crucial role on the prevention of brain's secondary damages even when primary disease is not on the CNS, as sepsis per example,(51) however, adjustment of these parameters are not enough if neurovascular coupling has been lost. (52) The limitation of chest wall and respiratory system elastances are correlated to elevation in ICP when positive-endexpiratory-pressure is applied, (53) what is expected for our population with obesity and SARS. These observations may justify the higher prevalence of ICCI among obese subjects in our study. ...
Objective
Multiple factors have been identified as causes of intracranial compliance impairment (ICCI) among patients with obesity. On the other hand, obesity has been linked with worst outcomes in COVID-19. Thus, the hypothesis of severe acute respiratory syndrome (SARS) conducing to cerebral hemodynamic disorders (CHD) able to worsen ICCI and play an additional role on prognosis determination for COVID-19 among obese patients becomes suitable.
Methods
50 cases of SARS by COVID-19 were evaluated, for the presence of ICCI and cerebrovascular circulatory disturbances in correspondence with whether unfavorable outcomes (death or impossibility for mechanical ventilation weaning [MVW]) within 7 days after evaluation. The objective was to observe whether obese patients (BMI ≥ 30) disclosed worse outcomes and tests results compared with lean subjects with same clinical background.
Results
23 (46%) patients among 50 had obesity. ICCI was verified in 18 (78%) obese, whereas in 13 (48%) of 27 non-obese (p = 0,029). CHD were not significantly different between groups, despite being high prevalent in both. 69% unfavorable outcomes were observed among obese and 44% for lean subjects (p = 0,075).
Conclusion
In the present study, intracranial compliance impairment was significantly more observed among obese subjects and may have contributed for SARS COVID-19 worsen prognosis.
... We would also argue against using a uniform positive end expiratory pressure (PEEP = 10 mmHg) among patients with and without raised ICP. A high PEEP can contribute to disputed ICP readings in patients with autoregulatory failure as seen in some cases of intracranial hypertension [4,5]. ...
... The implications of high PEEP to intraocular and intracranial pressures in steep Trendelenburg position need better understanding, and could be influenced by worsened chest wall compliance. 10 Airway closure during surgical pneumoperitoneum observed in obese patients creates challenges for accurate estimation of transpulmonary pressures. 11 A recently completed observational study will bring data on pulmonary complications and ventilatory settings during laparoscopic robotic surgery. ...
