The efficacy and tolerance of prone positioning in non-intubation patients with acute hypoxemic respiratory failure and ARDS: a meta-analysis

Comparison of the effectiveness of awake-prone positioning and high-flow nasal oxygen in patients with COVID-19-related acute respiratory failure between different waves

OBJECTIVE

To compare the effectiveness of the awake-prone position on relevant clinical outcomes in patients with COVID-19-related acute respiratory failure requiring high-flow nasal oxygen between different waves in Argentina.

METHODS

This multicenter, prospective cohort study included adult patients with COVID-19-related acute respiratory failure requiring high-flow nasal oxygen. The main exposure position was the awake-prone position (≥ 6 hours/day) compared to the non-prone position. The primary outcome was endotracheal intubation, and the secondary outcome was in-hospital mortality. The inverse probability weighting-propensity score was used to adjust the conditional probability of treatment assignment. We then adjusted for contextual variables that varied over time and compared the effectiveness between the first and second waves.

RESULTS

A total of 728 patients were included: 360 during the first wave and 368 during the second wave, of whom 195 (54%) and 227 (62%) remained awake-prone for a median (p25 - 75) of 12 (10 - 16) and 14 (8 - 17) hours/day, respectively (Awake-Prone Position Group). The ORs (95%CIs) for endotracheal intubation in the Awake-Prone Position Group were 0.25 (0.13 - 0.46) and 0.19 (0.09 - 0.31) for the first and second waves, respectively (p = 0.41 for comparison between waves). The ORs for in-hospital mortality in the awake-prone position were 0.35 (0.17 - 0.65) and 0.22 (0.12 - 0.43), respectively (p = 0.44 for comparison between waves).

CONCLUSION

The awake-prone position was associated with a reduction in the risk of endotracheal intubation and in-hospital mortality. These effects were independent of the context in which the intervention was applied, and no differences were observed between the different waves.

Guideline on positioning and early mobilisation in the critically ill by an expert panel

A scientific panel was created consisting of 23 interdisciplinary and interprofessional experts in intensive care medicine, physiotherapy, nursing care, surgery, rehabilitative medicine, and pneumology delegated from scientific societies together with a patient representative and a delegate from the Association of the Scientific Medical Societies who advised methodological implementation. The guideline was created according to the German Association of the Scientific Medical Societies (AWMF), based on The Appraisal of Guidelines for Research and Evaluation (AGREE) II. The topics of (early) mobilisation, neuromuscular electrical stimulation, assist devices for mobilisation, and positioning, including prone positioning, were identified as areas to be addressed and assigned to specialist expert groups, taking conflicts of interest into account. The panel formulated PICO questions (addressing the population, intervention, comparison or control group as well as the resulting outcomes), conducted a systematic literature review with abstract screening and full-text analysis and created summary tables. This was followed by grading the evidence according to the Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence and a risk of bias assessment. The recommendations were finalized according to GRADE and voted using an online Delphi process followed by a final hybrid consensus conference. The German long version of the guideline was approved by the professional associations. For this English version an update of the systematic review was conducted until April 2024 and recommendation adapted based on new evidence in systematic reviews and randomized controlled trials. In total, 46 recommendations were developed and research gaps addressed.

A randomised clinical trial of awake prone positioning in COVID-19 suspects with acute hypoxemic respiratory failure

Background

Awake prone position (APP) has been reported to improve oxygenation in patients with COVID-19 disease and to reduce the requirement for invasive mechanical ventilation for patients requiring support with high flow nasal cannula. There is conflicting data for patients requiring lower-level oxygen support.

Research question

Does APP reduce escalation of oxygen support in COVID-19 patients requiring supplementary oxygen?The primary outcome was defined as an escalation of oxygen support from simple supplementary oxygen (NP, HM, NRB) to NIV (CPAP or BiPAP), HFNC or IMV; OR from NIV (CPAP or BiPAP) or HFNC to IMV by day30.

Study design

Two center, prospective, non-blind, randomised controlled trial. Patients with confirmed or suspected COVID-19 pneumonia requiring ≥ 5 liters/min oxygen to maintain saturations ≥ 94 % were randomised to either APP or control group. The APP group received a 3-h APP session three times per day for three days.

Results

Between 9 May and July 13, 2021, 89 adults were screened and 61 enrolled, 31 to awake prone position and 30 controls. There was no difference in the primary outcome, 7 (22.6 %) patients randomised to APP and 9 (30.0 %) controls required escalation of oxygen support (OR 0.68 (0.22-2.14), P = 0.51). There were no differences in any secondary outcomes, in APP did not improve oxygenation.

Interpretation

In COVID-19 patients, the use of APP did not prevent escalation of oxygen support from supplementary to invasive or non-invasive ventilation or improve patient respiratory physiology.

Trial registration

NCT04853979 (clinicaltrials.gov).

Conscious prone positioning in nonintubated COVID-19 patients with acute respiratory distress syndrome: systematic review and meta-analysis

OBJECTIVE

To systematically review the effect of the prone position on endotracheal intubation and mortality in nonintubated COVID-19 patients with acute respiratory distress syndrome.

METHODS

We registered the protocol (CRD42021286711) and searched for four databases and gray literature from inception to December 31, 2022. We included observational studies and clinical trials. There was no limit by date or the language of publication. We excluded case reports, case series, studies not available in full text, and those studies that included children < 18-years-old.

RESULTS

We included ten observational studies, eight clinical trials, 3,969 patients, 1,120 endotracheal intubation events, and 843 deaths. All of the studies had a low risk of bias (Newcastle-Ottawa Scale and Risk of Bias 2 tools). We found that the conscious prone position decreased the odds of endotracheal intubation by 44% (OR 0.56; 95%CI 0.40 - 0.78) and mortality by 43% (OR 0.57; 95%CI 0.39 - 0.84) in nonintubated COVID-19 patients with acute respiratory distress syndrome. This protective effect on endotracheal intubation and mortality was more robust in those who spent > 8 hours/day in the conscious prone position (OR 0.43; 95%CI 0.26 - 0.72 and OR 0.38; 95%CI 0.24 - 0.60, respectively). The certainty of the evidence according to the GRADE criteria was moderate.

CONCLUSION

The conscious prone position decreased the odds of endotracheal intubation and mortality, especially when patients spent over 8 hours/day in the conscious prone position and treatment in the intensive care unit. However, our results should be cautiously interpreted due to limitations in evaluating randomized clinical trials, nonrandomized clinical trials and observational studies. However, despite systematic reviews with meta-analyses of randomized clinical trials, we must keep in mind that these studies remain heterogeneous from a clinical and methodological point of view.

Prone positioning effect on tracheal intubation rate, mortality and oxygenation parameters in awake non-intubated severe COVID-19-induced respiratory failure: a review of reviews

BACKGROUND

Prone positioning (PP) is a low-cost method with minimal risk to the patient that improves the oxygenation of patients with acute hypoxic respiratory failure (AHRF) due to COVID-19 pneumonia, thereby reducing their need for tracheal intubation (TI) and transferring to the intensive care unit (ICU). We aimed to overview the results of all previous systematic reviews and meta-analyses to examine the net effect of PP on oxygenation, the rate of TI and mortality in COVID-19 patients.

METHODS

We searched PubMed, Scopus, Web of Science, Google Scholar, and Cochrane Library databases from December 2019 through 2022 without publication language restriction for systematic reviews and meta-analysis studies on PP vs. supine position (SP) in conscious patients with hypoxic respiratory failure COVID-19. After study selection, data were extracted from published meta-analyses and pooled by comprehensive meta-analysis (CMA) software version 2.2.064 to achieve effect sizes. They were analyzed for TI and mortality rates dichotomous variables, and the results were shown as pooled odds ratios (OR) with a 95% confidence interval (CI). Continuous variables such as oxygenation indices (PaO2/FiO2 and SpO2) were also analyzed, and the data were shown as mean differences (MD) with lower and upper CI. The level of statistical significance was set at p ≤ 0.05.

RESULTS

Twelve systematic reviews and meta-analyses with 19,651 patients and six systematic reviews with 2,911 patients were included in this Review of Reviews (total: 22,562). PP treatment significantly reduced the rate of TI (OR = 0.639, %95 CI (0.492, 0.829); P-value = 0.001) and decreased mortality (OR = 0.363, %95 CI (0.240, 0.549), P-value < 0.001). There was no difference in PaO2/FiO2 (MD = 3.591[- 40.881, 48.062]; P-value = 0.874) and SpO2 percent (MD = 1.641[- 4.441, 7.723]; P-value = 0.597).

CONCLUSION

Prone positioning can be recommended in conscious ICU patients with COVID-19 pneumonia to reduce mortality and intubation.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number: CRD42022326951. Registered 25 April 2022.

Awake prone positioning for patients with COVID-19-related respiratory failure: a systematic review and meta-analysis

The role of awake prone positioning (aPP) in patients with acute hypoxemic respiratory failure is debated. We performed a systematic review and meta-analysis to evaluate the role of aPP in acute respiratory failure related to COronaVIrus Disease-19 (COVID-19). Studies reporting on the clinical course of patients with acute respiratory failure related to COVID-19 treated or not treated by aPP were included in the systematic review and meta-analysis (ProsperoID: CRD42022333211). The primary study outcome was the composite of in-hospital death or orotracheal intubation; the individual components of the primary outcome were secondary study outcomes. The composite of in-hospital death or orotracheal intubation was available for 6 studies (1884 patients), five randomized and one prospective; a significant reduction in the risk of this outcome was observed in patients treated vs. not treated by aPP (33.5% vs. 39.8%; OR 0.73, 95% CI 0.60-0.89; I2 0%). In-hospital death was reported in 34 studies (6808 patients) and occurred in 17.4% vs. 23.5% of patients treated or not treated with aPP (random effect OR 0.60, 95% CI 0.46-0.79; I2 59%); orotracheal intubation was observed in 25.8% vs. 32.7% of patients treated or not treated with aPP (27 studies, 5369 patients; random effect OR 0.85, 95% CI 0.56-1.27; I2 84%). aPP reduces the risk for death or orotracheal intubation in patients with acute respiratory failure related to COVID-19. Further studies should be conducted to confirm the clinical benefit of aPP outside the ICU.Registration Prospero ID: CRD42022333211.

Prone Positioning for Patients With COVID-19-Induced Acute Hypoxemic Respiratory Failure: Flipping the Script

During the COVID-19 pandemic, prone positioning (PP) emerged as a widely used supportive therapy for patients with acute hypoxemic respiratory failure caused by COVID-19 infection. In particular, awake PP (APP)-the placement of non-intubated patients in the prone position-has gained popularity and hence is detailed first herein. This review discusses recent publications on the use of PP for non-intubated and intubated subjects with COVID-19, highlighting the physiological responses, clinical outcomes, influential factors affecting treatment success, and strategies to improve adherence with APP. The use of prolonged PP and the use of PP for patients undergoing extracorporeal membrane oxygenation are also presented.

Effects of lithotomy and prone positions on hemodynamic parameters, respiratory mechanics, and arterial oxygenation in percutaneous nephrolithotomy performed under general anesthesia

AIM

The position of the body during surgery may affect the patient's body functions, especially the hemodynamic parameters. We aimed to comparatively analyze the effects of lithotomy and prone position on respiratory mechanics, arterial oxygenation, and hemodynamic parameters in patients who underwent percutaneous nephrolithotomy (PNL).

Awake Prone Decubitus Positioning in COVID-19 Patients: A Systematic Review and MetaAnalysis

To date, recommendations for the implementation of awake prone positioning in patients with hypoxia secondary to SARSCoV2 infection have been extrapolated from prior studies on respiratory distress. Thus, we carried out a systematic review and metaanalysis to evaluate the benefits of pronation on the oxygenation, need for endotracheal intubation (ETI), and mortality of this group of patients. We carried out a systematic search in the PubMed and Embase databases between June 2020 and November 2021. A randomeffects metaanalysis was performed to evaluate the impact of pronation on the ETI and mortality rates. A total of 213 articles were identified, 15 of which were finally included in this review. A significant decrease in the mortality rate was observed in the group of pronated patients (relative risk [RR] = 0.69; 95% confidence interval [CI]: 0.480.99; p = 0.044), but no significant effect was observed on the need for ETI (RR = 0.79; 95% CI: 0.631.00; p = 0.051). However, a subgroup analysis of randomized clinical trials (RCTs) did reveal a significant decrease in the need for this intervention (RR = 0.83; 95% CI: 0.710.97). Prone positioning was found to significantly reduce mortality, also diminishing the need for ETI, although this effect was statistically significant only in the subgroup analysis of RCTs. Patients' response to awake prone positioning could be greater when this procedure is implemented early and in combination with noninvasive mechanical ventilation (NIMV) or highflow nasal cannula (HFNC) therapy.

Prone position: how understanding and clinical application of a technique progress with time

Historical background

The prone position was first proposed on theoretical background in 1974 (more advantageous distribution of mechanical ventilation). The first clinical report on 5 ARDS patients in 1976 showed remarkable improvement of oxygenation after pronation. 

Pathophysiology

The findings in CT scans enhanced the use of prone position in ARDS patients. The main mechanism of the improved gas exchange seen in the prone position is nowadays attributed to a dorsal ventilatory recruitment, with a substantially unchanged distribution of perfusion. Regardless of the gas exchange, the primary effect of the prone position is a more homogenous distribution of ventilation, stress and strain, with similar size of pulmonary units in dorsal and ventral regions. In contrast, in the supine position the ventral regions are more expanded compared with the dorsal regions, which leads to greater ventral stress and strain, induced by mechanical ventilation.

Outcome in ARDS

The number of clinical studies paralleled the evolution of the pathophysiological understanding. The first two clinical trials in 2001 and 2004 were based on the hypothesis that better oxygenation would lead to a better survival and the studies were more focused on gas exchange than on lung mechanics. The equations better oxygenation = better survival was disproved by these and other larger trials (ARMA trial). However, the first studies provided signals that some survival advantages were possible in a more severe ARDS, where both oxygenation and lung mechanics were impaired. The PROSEVA trial finally showed the benefits of prone position on mortality supporting the thesis that the clinical advantages of prone position, instead of improved gas exchange, were mainly due to a less harmful mechanical ventilation and better distribution of stress and strain. In less severe ARDS, in spite of a better gas exchange, reduced mechanical stress and strain, and improved oxygenation, prone position was ineffective on outcome.

Prone position and COVID-19

The mechanisms of oxygenation impairment in early COVID-19 are different than in typical ARDS and relate more on perfusion alteration than on alveolar consolidation/collapse, which are minimal in the early phase. Bronchial shunt may also contribute to the early COVID-19 hypoxemia. Therefore, in this phase, the oxygenation improvement in prone position is due to a better matching of local ventilation and perfusion, primarily caused by the perfusion component. Unfortunately, the conditions for improved outcomes, i.e. a better distribution of stress and strain, are almost absent in this phase of COVID-19 disease, as the lung parenchyma is nearly fully inflated. Due to some contradictory results, further studies are needed to better investigate the effect of prone position on outcome in COVID-19 patients.

Graphical Abstract

Early Prone versus Supine Positioning in Moderate to Severe Coronavirus Disease 2019 Patients with Acute Respiratory Distress Syndrome

Objectives

This study sought to determine whether early prone positioning of patients with moderate to severe COVID-19-related acute respiratory distress syndrome (ARDS) lowers the mortality rate.

Methods

We conducted a retrospective study using data from intensive care units of two tertiary centers in Oman. Adult patients with moderate to severe COVID-19-related ARDS with a PaO2/FiO2 ratio < 150 on FiO2 of 60% or more and a positive end-expiratory pressure of at least 8 cm H2O who were admitted between 1 May 2020 and 31 October 2020 were selected as participants. All patients were intubated and subjected to mechanical ventilation within 48 hours of admission and placed in either prone or supine position. Mortality was measured and compared between the patients from the two groups.

Results

A total of 235 patients were included (120 in the prone group and 115 in the supine group). There were no significant differences in mortality (48.3% vs. 47.8%; p =0.938) and discharge rates (50.8% vs. 51.3%; p =0.942) between the prone and supine groups, respectively.

Conclusions

Early prone positioning of patients with COVID-19-related ARDS does not result in a significant reduction in mortality.

Awake prone positioning for patients with COVID-19-induced acute hypoxemic respiratory failure

Whereas prone positioning of intubated patients suffering from acute respiratory distress syndrome represents the standard of care, proning non-intubated patients, so-called "awake prone positioning (APP)," has only recently gained popularity and undergone scientific evaluation. In this review, we summarize current evidence on physiological and clinical effects of APP on patients' centered outcomes, such as intubation and mortality, the safety of the technique, factors and predictors of success, practical issues for optimal implementation, and future areas of research. Current evidence supports using APP among patients suffering from acute hypoxemic respiratory failure due to COVID-19 and undergoing advanced respiratory support, such as high-flow nasal cannula, in an intensive care unit setting. Healthcare teams should aim to prone patients at least 8 h daily. Future research should focus on optimizing the tolerance of the technique and comprehensively evaluating benefits in other patient populations.

Awake prone positioning for patients with COVID-19 pneumonia in intensive care unit: A systematic review and meta-analysis

Background

Awake prone positioning (APP) has been widely used in non-intubated COVID-19 patients during the pandemic. However, high-quality evidence to support its use in severe COVID-19 patients in an intensive care unit (ICU) is inadequate. Therefore, we aimed to assess the efficacy and safety of APP for intubation requirements and other important outcomes in this patient population.

Methods

We searched for potentially relevant articles in PubMed, Embase, and the Cochrane database from inception to May 25, 2022. Studies focusing on COVID-19 adults in ICU who received APP compared to controls were included. The primary outcome was the intubation requirement. Secondary outcomes were mortality, ICU stay, and adverse events. Study quality was independently assessed, and we also conducted subgroup analysis, sensitivity analysis, and publication bias to explore the potential influence factors.

Results

Ten randomized controlled trials with 1,686 patients were eligible. The quality of the included studies was low to moderate. Overall, the intubation rate was 35.2% in the included patients. The mean daily APP duration ranged from &lt;6 to 9 h, with poor adherence to APP protocols. When pooling, APP significantly reduced intubation requirement (risk ratio [RR] 0.84; 95%CI, 0.74–0.95; I2 = 0%, P = 0.007). Subgroup analyses confirmed the reduced intubation rates in patients who were older (≥60 years), obese, came from a high mortality risk population (&gt;20%), received HFNC/NIV, had lower SpO2/FiO2 (&lt;150 mmHg), or undergone longer duration of APP (≥8 h). However, APP showed no beneficial effect on mortality (RR 0.92 [95% CI 0.77–1.10; I2 = 0%, P = 0.37] and length of ICU stay (mean difference = −0.58 days; 95% CI, −2.49 to 1.32; I2 = 63%; P = 0.55).

Conclusion

APP significantly reduced intubation requirements in ICU patients with COVID-19 pneumonia without affecting the outcomes of mortality and ICU stay. Further studies with better APP protocol adherence will be needed to define the subgroup of patients most likely to benefit from this strategy.

COVID-19 Lessons Learned: Prone Positioning With and Without Invasive Ventilation

Prone positioning (PP) has been used extensively for patients requiring invasive mechanical ventilation for hypoxemic respiratory failure during the COVID-19 pandemic. Evidence suggests that PP was beneficial during the pandemic, as it improves oxygenation and might improve chances of survival, especially in those with a continuum of positive oxygenation responses to the procedure. Additionally, the pandemic drove innovation regarding PP, as it brought attention to awake PP (APP) and the value of an interdisciplinary team approach to PP during a pandemic. APP appears to be safe and effective at improving oxygenation; APP may also reduce the need for intubation in patients requiring advanced respiratory support like high-flow nasal cannula or noninvasive ventilation. Teams specifically assembled for PP during a pandemic also appear useful and can provide needed assistance to bedside clinicians in the time of crisis. Complications associated with PP can be mitigated, and a multidisciplinary approach to reduce the incidence of complications is recommended.

Posición prono en respiración espontánea: una lección más del COVID-19

Con la pandemia se implementaron diversas estrategias para evitar la intubación y la ventilación mecánica invasiva. La posición prona tiene claros efectos benéficos en mejorar la oxigenación por diversos mecanismos al tiempo que genera cambios hemodinámicos que pueden optimizar la función del ventrículo derecho.

La evidencia de la posición prona en pacientes con síndrome de dificultad respiratoria aguda en ventilación mecánica invasiva es contundente y obliga a considerarla en las primeras 24 h de pacientes con PaO₂/FiO₂ ≤ 150 mmHg. La posición prona en respiración espontánea puede mejorar la oxigenación en pacientes con falla respiratoria y si se implementa mediante un protocolo que incluya una adecuada selección de pacientes puede evitar la intubación de pacientes en falla respiratoria.

La presente revisión resume los antecedentes históricos, las bases fisiológicas de la posición prona en el paciente despierto, así como la evidencia que evalúa su aplicación en el paciente con COVID-19 al tiempo que resume el protocolo y la experiencia de un centro con esta estrategia como propuesta para estudios multicéntricos.

Comparison of COVID-19 Induced Respiratory Failure and Typical ARDS: Similarities and Differences

Coronavirus disease 2019 (COVID-19) is a predominantly respiratory infectious disease caused by novel coronavirus infection (SARS-CoV-2), respiratory failure is the main clinical manifestation and the leading cause of death. Even though it can meet the acute respiratory distress syndrome (ARDS) Berlin definition, only some clinical features of COVID-19 are consistent with typical ARDS, and which has its own peculiar phenotypes. When compared with typical ARDS, in addition to the typical diffuse alveolar injury, COVID-19 has unique pathological and pathophysiological features, such as endothelial injury, extensive microthrombus, and pulmonary capillary hyperplasia. The clinical features of patients with respiratory failure caused by COVID-19 are heterogeneous and can be generally divided into two phenotypes: progressive respiratory distress and unique "silent hypoxemia". The "H-type" characteristics of reduced lung volume, decreased lung compliance, and unmatched ventilator-perfusion ratio. While some patients may have close to normal lung compliance, that is "L-type". Identifying the exact phenotype in whom are suffered with COVID-19 is crucial to guide clinicians to adopt appropriate treatment strategies. This review discussed the similarities and differences in the pathogenesis, pathophysiology, clinical features and treatment strategies of COVID-19 induced acute respiratory failure and typical ARDS.

Effect of Prone Positioning on Clinical Outcomes of Non-Intubated Subjects With COVID-19

BACKGROUND

Awake prone positioning (APP) has been recently proposed as an adjunctive treatment for non-intubated coronavirus disease 2019 (COVID-19) patients requiring oxygen therapy to improve oxygenation and reduce the risk of intubation. However, the magnitude of the effect of APP on clinical outcomes in these patients remains uncertain. We performed a comparative systematic review and meta-analysis to evaluate the effectiveness of APP to improve the clinical outcomes in non-intubated subjects with COVID-19.

METHODS

The primary outcomes were the need for endotracheal intubation and mortality. The secondary outcome was hospital length of stay. Pooled risk ratio (RR) and mean difference with the corresponding 95% CI were obtained by the Mantel-Haenszel method within a random-effect model.

RESULTS

A total of 14 studies (5 randomized controlled trials [RCTs] and 9 observational studies) involving 3,324 subjects (1,495 received APP and 1,829 did not) were included. There was a significant reduction in the mortality rate in APP group compared to control (RR 0.68 [95% CI 0.51-0.90]; P = .008, I² = 52%) with no significant effect on intubation (RR 0.85 [95% CI 0.66-1.08]; P = .17, I² = 63%) or hospital length of stay (mean difference -3.09 d [95% CI-10.14-3.96]; P = .39, I² = 97%). Subgroup analysis of RCTs showed significant reduction in intubation rate (RR 0.83 [95% CI 0.72-0.97]; P = .02, I² = 0%).

CONCLUSIONS

APP has the potential to reduce the in-hospital mortality rate in COVID-19 subjects with hypoxemia without a significant effect on the need for intubation or length of hospital stay. However, there was a significant decrease in the need for intubation on subgroup analysis of RCTs. More large-scale trials with a standardized protocol for prone positioning are needed to better evaluate its effectiveness in this select population.

Predictor factors for non-invasive mechanical ventilation failure in severe COVID-19 patients in the intensive care unit: a single-center retrospective study

BACKGROUND

During the COVID-19 pandemia, non-invasive mechanical ventilation (NIV) has been largely applied. Few data are available about predictors of NIV failure in critical COVID-19 patients admitted to ICU. The aim of this study is to analyze clinical and laboratory features able to predict non-invasive ventilation success in avoiding endotracheal intubation.

METHODS

A retrospective observational study was performed in our COVID-19 ICU during a 6-month period. Demographic, clinical, laboratory, imaging, and outcome data were extracted from electronic and paper medical records and anonymously collected.

RESULTS

Eighty-two severe COVID-19 patients were supported by NIV at ICU admission. The median PaO2/FiO2 ratio was 125 [98.5-177.7]. NIV failed in 44 cases (53%). Patients who experienced NIV failure had a higher Charlson Comorbidity Index (median value 4) compared to those who were dismissed without endotracheal intubation (median 2, p < 0.0001). At Cox regression analysis, the Charlson Comorbidity Index represented a predictive factor related to NIV failure. PaO2/FiO2, CPK, INR, and AT III at ICU admission showed a significant relationship with the outcome, when single variables were adjusted for the Charlson Comorbidity Index.

CONCLUSION

The Charlson Comorbidity Index may be helpful to stratify patients' risk of NIV failure in a severe COVID-19 population; even if this study, retrospective design does not allow definitive conclusions.

Impact of exposure time in awake prone positioning on clinical outcomes of patients with COVID-19-related acute respiratory failure treated with high-flow nasal oxygen: a multicenter cohort study

Background

In patients with COVID-19-related acute respiratory failure (ARF), awake prone positioning (AW-PP) reduces the need for intubation in patients treated with high-flow nasal oxygen (HFNO). However, the effects of different exposure times on clinical outcomes remain unclear. We evaluated the effect of AW-PP on the risk of endotracheal intubation and in-hospital mortality in patients with COVID-19-related ARF treated with HFNO and analyzed the effects of different exposure times to AW-PP.

Methods

This multicenter prospective cohort study in six ICUs of 6 centers in Argentine consecutively included patients > 18 years of age with confirmed COVID-19-related ARF requiring HFNO from June 2020 to January 2021. In the primary analysis, the main exposure was awake prone positioning for at least 6 h/day, compared to non-prone positioning (NON-PP). In the sensitivity analysis, exposure was based on the number of hours receiving AW-PP. Inverse probability weighting–propensity score (IPW-PS) was used to adjust the conditional probability of treatment assignment. The primary outcome was endotracheal intubation (ETI); and the secondary outcome was hospital mortality.

Results

During the study period, 580 patients were screened and 335 were included; 187 (56%) tolerated AW-PP for [median (p25–75)] 12 (9–16) h/day and 148 (44%) served as controls. The IPW–propensity analysis showed standardized differences < 0.1 in all the variables assessed. After adjusting for other confounders, the OR (95% CI) for ETI in the AW-PP group was 0.36 (0.2–0.7), with a progressive reduction in OR as the exposure to AW-PP increased. The adjusted OR (95% CI) for hospital mortality in the AW-PP group ≥ 6 h/day was 0.47 (0.19–1.31). The exposure to prone positioning ≥ 8 h/d resulted in a further reduction in OR [0.37 (0.17–0.8)].

Conclusion

In the study population, AW-PP for ≥ 6 h/day reduced the risk of endotracheal intubation, and exposure ≥ 8 h/d reduced the risk of hospital mortality.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03881-2.

Response to Awake Prone Position in Nonintubated Individuals With COVID-19

BACKGROUND

Prone positioning is used for patients with ARDS undergoing invasive mechanical ventilation; its effectiveness in nonventilated awake patients is unclear. We aimed to evaluate the effectiveness of the prone maneuver in decreasing the risk of intubation and increasing the odds of favorable events.

METHODS

We prospectively evaluated 66 subjects with COVID-19-related moderate ARDS who were admitted to the ICU; treated with high-flow nasal cannula, noninvasive ventilation, a reservoir mask, or a nasal cannula; and subjected to awake prone maneuvers from March 1, 2020-August 30, 2020. The following factors were recorded at ICU admission: age, sex, prior illness, simplified acute physiology score 3, body mass index, and changes in gas exchange after and before prone positioning. Subjects were divided into a group of responders and nonresponders according to a 20% increase in the P_aO2 /F_IO2 ratio before and after the maneuver. The need for intubation within 48 h of the start of the maneuver was also evaluated. We also analyzed the differences in mortality, ICU length of stay, hospital length of stay, and duration of mechanical ventilation. A generalized estimating equation model was applied to preprone and postprone means. To control for confounding factors, multivariate Poisson regression was applied.

RESULTS

Forty-one subjects age 54.1 y ± 12.9 were enrolled. Responders showed increased S_pO2 (P < .001), P_aO2 (P < .001), and P_aO2 /F_IO2 ratios (P < .001) with the maneuver and reduced breathing frequency. Responders had shorter lengths of stay in the ICU (P < .001) and hospital (P < .003), lower intubation rates at 48 h (P < .012), fewer days of ventilation (P < .02), and lower mortality (P < .001). Subjects who responded to the maneuver had a 54% reduction in the risk of ventilation and prolonged stay in the ICU.

CONCLUSIONS

Among the responders to prone positioning, there were fewer deaths, shorter duration of mechanical ventilation, shorter ICU length of stay, and shorter hospital length of stay.