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The main settings, benefits, and pitfalls of noninvasive respiratory supports in patients with AHRF/ARDS.
Source publication
Acute respiratory distress syndrome (ARDS) is a leading cause of disability and mortality worldwide, and while no specific etiologic interventions have been shown to improve outcomes, noninvasive and invasive respiratory support strategies are life-saving interventions that allow time for lung recovery. However, the inappropriate management of thes...
Contexts in source publication
Context 1
... delivers a heated and humidified gas flow mixture of oxygen and air up to 60 L/min, with a set F I O 2 up to 100% through the large bore nasal cannula (i.e., highflow nasal oxygen therapy, HFNOT) [34,43,44] (Table 1). The main physiological effects of HFOT are as follows: the accurate delivery of a set F I O 2 that matches the patient's peak inspiratory flow and allows for a reliable evaluation of the P a O 2 /F I O 2 ratio [7]; a washout of nasopharyngeal dead space, which increases ventilatory efficiency and reduces the work of breathing; a flow-dependent positive pressure effect (3-5 cmH2O), which allows for lung recruitment, improved oxygenation, and improved lung mechanics; the active humidification and heating of the upper airways, favoring secretion hydration and clearance; and patient's comfort [45,46]. ...Context 2
... main physiological effects of HFOT are as follows: the accurate delivery of a set F I O 2 that matches the patient's peak inspiratory flow and allows for a reliable evaluation of the P a O 2 /F I O 2 ratio [7]; a washout of nasopharyngeal dead space, which increases ventilatory efficiency and reduces the work of breathing; a flow-dependent positive pressure effect (3-5 cmH2O), which allows for lung recruitment, improved oxygenation, and improved lung mechanics; the active humidification and heating of the upper airways, favoring secretion hydration and clearance; and patient's comfort [45,46]. [47] (its detailed description is summarized in Table 1 [34,43]). Briefly, the positive pressures of 5-8 cmH 2 O for face masks (higher pressures may lead to proportionally increased air leakage with consequent mismatches between set and delivered pressures, which potentially implies a lower efficacy for this therapy) and 10-15 cmH 2 O for helmets are generated by a flow generator (compressed gases or turbine) or a Venturi system that provides a continuous fresh gas flow to the inlet port while the outlet port is regulated by a PEEP valve [34,43]. ...Context 3
... allows for the application of a biphasic positive airway pressure (PEEP + pressure support, PS). It is generated by a mechanical ventilator and delivered via face-mask or helmet interfaces [34,43,44] (Table 1). Active humidification is recommended only for face-mask NIV, while it is not required for helmet-NIV when the total system minute ventilation exceeds 40 L/min [28,56,57]. ...Similar publications
Background
Airway opening pressure (AOP) detection and measurement are essential for assessing respiratory mechanics and adapting ventilation. We propose a novel approach for AOP assessment during volume assist control ventilation at a usual constant-flow rate of 60 L/min.
Objectives
To validate the conductive pressure ( P cond ) method, which com...
Citations
... KEYWORDS hematopoietic cell transplant, intubation, mechanical ventilation, palliative care, noninvasive ventilation associated lung injury, oxygen toxicity Introduction Delayed intubation and prolonged use of NIV and supplemental oxygen have been implicated as potential risk factors for poor outcome in pediatric hematopoietic cell transplant patients with Pediatric Acute Respiratory Distress Syndrome (PARDS) (1)(2)(3). Additionally, recent data has shown that lung injury from NIV may be underappreciated and contribute to the suboptimal outcomes for HCT patients who develop PARDS (4,5). While much discussion has centered on the need for earlier intervention in this high-risk population (6), retrospective data suggests pediatric intensivists may intubate this population late in their PARDS course as evidenced by the very high rate of cardiac arrest during intubation when compared to the general pediatric population (1,2,7,8). ...
Introduction
Retrospective data suggest that pediatric hematopoietic cell transplant (HCT) patients placed on non-invasive ventilation (NIV) prior to intubation have increased risk of mortality compared to patients who are intubated earlier in their course. The HCT-CI subgroup of the PALISI Network set out to gain a better understanding of factors that influence clinician’s decisions surrounding timing of intubation of pediatric HCT patients.
Methods
We validated and distributed a brief survey exploring potential factors that may influence clinician’s decisions around timing of intubation of pediatric HCT patients with acute lung injury (ALI).
Results
One hundred and four of the 869 PALISI Network’s members responded to the survey; 97 of these respondents acknowledged caring for HCT patients and were offered the remainder of the survey. The majority of respondents were PICU physicians (96%), with a small number of Advanced Practice Providers and HCT physicians. As expected, poor prognosis categories were perceived as a factors that delay timing to intubation whereas need for invasive procedures was perceived as a factor shortening timing to intubation. Concerns for oxygen toxicity or NIV-associated lung injury were not believed to influence timing of intubation.
Discussion
Our survey indicates increased risk of ALI from prolonged NIV and oxygen toxicity in HCT patients are not a concern for most clinicians. Further education of pediatric ICU clinicians around these risk factors could lead to improvement in outcomes and demands further study. Additionally, clinicians identified concerns for the patient’s poor prognosis as a common reason for delayed intubation.
... Subdividing ARDS patients into categories reflecting different severities or modifiable pathophysiological processes represents the most critical advance for precision medicine in ARDS. It provides a rationale for identifying patients that are resistant to therapy, or who should be the target for aggressive and innovative therapies, or in whom endotracheal intubation and MV could be avoided, or who should be excluded from some clinical trials [33][34][35]. Most studies on sub-phenotypes in ARDS to date are based on retrospective analyses [36] and it is unclear whether those subtypes of patients represent categorization of the etiologic underlying disease or of ARDS itself [30,37]. ...
Although the defining elements of “acute respiratory distress syndrome” (ARDS) have been known for over a century, the syndrome was first described in 1967. Since then, despite several revisions of its conceptual definition, it remains a matter of debate whether ARDS is a discrete nosological entity. After almost 60 years, it is appropriate to examine how critical care has modeled this fascinating syndrome and affected patient’s outcome. Given that the diagnostic criteria of ARDS (e.g., increased pulmonary vascular permeability and diffuse alveolar damage) are difficult to ascertain in clinical practice, we believe that a step forward would be to standardize the assessment of pulmonary and extrapulmonary involvement in ARDS to ensure that each patient can receive the most appropriate and effective treatment. The selection of treatments based on arbitrary ranges of PaO 2 /FiO 2 lacks sufficient sensitivity to individualize patient care.
... The subject matter was carefully chosen so as to emphasize-and focus on-relevant works in pulmonary pathophysiology and lung disease treatment. The aforementioned topics are of the highest priority among the scientific and medical community since the corresponding complications (e.g., sepsis and lung injury) are associated with unacceptably high mortality rates [1,2]. Experts in the field were invited to contribute their works to this Special Issue, and fifteen articles of the highest quality were accepted for publication following rigorous evaluation. ...
It has been my great pleasure to have joined forces with Pharmaceutical’s editorial team in order to organize and publish a Special Issue on “Lung Injury and Repair” [...]
... Although the absolute increase in ΔP ES was limited in our cohort, our results may indicate that awake prone positioning may not be indicated for all patients with acute hypoxemic respiratory failure, but only for those exhibiting low-to-normal ΔP ES . Those with high ΔP ES are rather likely to benefit from an approach specifically aimed at reducing the inspiratory effort: this may explain why noninvasive ventilation (that best reduces ΔP ES ) may result in reduced rate of intubation vs. high-flow nasal oxygen combined with prone position among patients with high ΔP ES [19,[59][60][61]. Discrepancy between the huge clinical benefit by prone positioning in intubated patients vs. the milder observed in non-intubated patients may be related to the inability of the intervention to modulate ΔP ES . ...
Background:
The effects of awake prone position on the breathing pattern of hypoxemic patients need to be better understood. We conducted a crossover trial to assess the physiological effects of awake prone position in patients with acute hypoxemic respiratory failure.
Methods:
Fifteen patients with acute hypoxemic respiratory failure and PaO2/FiO2 < 200 mmHg underwent high-flow nasal oxygen for 1 h in supine position and 2 h in prone position, followed by a final 1-h supine phase. At the end of each study phase, the following parameters were measured: arterial blood gases, inspiratory effort (ΔPES), transpulmonary driving pressure (ΔPL), respiratory rate and esophageal pressure simplified pressure-time product per minute (sPTPES) by esophageal manometry, tidal volume (VT), end-expiratory lung impedance (EELI), lung compliance, airway resistance, time constant, dynamic strain (VT/EELI) and pendelluft extent through electrical impedance tomography.
Results:
Compared to supine position, prone position increased PaO2/FiO2 (median [Interquartile range] 104 mmHg [76-129] vs. 74 [69-93], p < 0.001), reduced respiratory rate (24 breaths/min [22-26] vs. 27 [26-30], p = 0.05) and increased ΔPES (12 cmH2O [11-13] vs. 9 [8-12], p = 0.04) with similar sPTPES (131 [75-154] cmH2O s min-1 vs. 105 [81-129], p > 0.99) and ΔPL (9 [7-11] cmH2O vs. 8 [5-9], p = 0.17). Airway resistance and time constant were higher in prone vs. supine position (9 cmH2O s arbitrary units-3 [4-11] vs. 6 [4-9], p = 0.05; 0.53 s [0.32-61] vs. 0.40 [0.37-0.44], p = 0.03). Prone position increased EELI (3887 arbitrary units [3414-8547] vs. 1456 [959-2420], p = 0.002) and promoted VT distribution towards dorsal lung regions without affecting VT size and lung compliance: this generated lower dynamic strain (0.21 [0.16-0.24] vs. 0.38 [0.30-0.49], p = 0.004). The magnitude of pendelluft phenomenon was not different between study phases (55% [7-57] of VT in prone vs. 31% [14-55] in supine position, p > 0.99).
Conclusions:
Prone position improves oxygenation, increases EELI and promotes VT distribution towards dependent lung regions without affecting VT size, ΔPL, lung compliance and pendelluft magnitude. Prone position reduces respiratory rate and increases ΔPES because of positional increases in airway resistance and prolonged expiratory time. Because high ΔPES is the main mechanistic determinant of self-inflicted lung injury, caution may be needed in using awake prone position in patients exhibiting intense ΔPES. Clinical trail registeration: The study was registered on clinicaltrials.gov (NCT03095300) on March 29, 2017.
Severe acute respiratory failure (ARF) is a major issue in patients with severe community-acquired pneumonia (CAP). Standard oxygen therapy is the first-line therapy for ARF in the less severe cases. However, respiratory supports may be delivered in more severe clinical condition. In cases with life-threatening ARF, invasive mechanical ventilation (IMV) will be required. Noninvasive strategies such as high-flow nasal therapy (HFNT) or noninvasive ventilation (NIV) by either face mask or helmet might cover the gap between standard oxygen and IMV. The objective of all the supporting measures for ARF is to gain time for the antimicrobial treatment to cure the pneumonia. There is uncertainty regarding which patients with severe CAP are most likely to benefit from each noninvasive support strategy. HFNT may be the first-line approach in the majority of patients. While NIV may be relatively contraindicated in patients with excessive secretions, facial hair/structure resulting in air leaks or poor compliance, NIV may be preferable in those with increased work of breathing, respiratory muscle fatigue, and congestive heart failure, in which the positive pressure of NIV may positively impact hemodynamics. A trial of NIV might be considered for select patients with hypoxemic ARF if there are no contraindications, with close monitoring by an experienced clinical team who can intubate patients promptly if they deteriorate. In such cases, individual clinician judgement is key to choose NIV, interface, and settings. Due to the paucity of studies addressing IMV in this population, the protective mechanical ventilation strategies recommended by guidelines for acute respiratory distress syndrome can be reasonably applied in patients with severe CAP.
Personalized ventilation strategies, including the application of PEEP, can lead to better patient outcomes. The literature suggests moving away from a one-size-fits-all approach to PEEP in ARDS and supports the need for individualized PEEP settings based on patient response. The application of protective ventilation strategies with PEEP is also shown to be beneficial in non-ARDS scenarios, such as during surgery, indicating the broad relevance of these approaches. However, there remains a lack of definitive guidance on how to determine the optimal PEEP for each patient, signaling the need for further research in this area.
The review aims to contribute to the ongoing discourse on the optimization of PEEP, ultimately aiming to inform clinical decision-making and improve patient outcomes.
