Critical Care Bulletin: September 2021

 

To prone or not to prone ARDS patients on ECMO

by Oriol Roca, Andrés Pacheco and Marina García-de-Acilu 

Critical Care volume 25, Article number: 315 (2021) Published: 31 August 2021

The prone position is recommended as a supportive therapy in patients with moderate- to-severe acute respiratory distress syndrome (ARDS). It is usually associated with improved oxygenation and pulmonary mechanics as the result of a more homogeneous distribution of mechanical forces and better ventilation/perfusion (V/Q) matching. These effects lead to a lower risk of aggravating preexisting lung injury and, ultimately, a decrease in mortality. Despite widespread use of the prone position in patients with ARDS, even in awake non-intubated spontaneously breathing patients, its use dramatically decreases once the patient has been placed on extracorporeal membrane oxygenation (ECMO). In this chapter, we discuss the available evidence regarding use of the prone position in ARDS patients treated with ECMO.

 

Monitoring and modifying brain oxygenation in patients at risk of hypoxic ischaemic brain injury after cardiac arrest

 

by Markus Benedikt Skrifvars, Mypinder Sekhon and Erik Anders Åneman 

Critical Care volume 25, Article number: 312 (2021) Published: 31 August 2021

The majority of adverse clinical outcomes following successful resuscitation from cardiac arrest, are attributable to hypoxic ischemic brain injury [1]. The cornerstone of hypoxic ischemic brain injury management has traditionally focused on preventing secondary ischemic injury, following the return of spontaneous circulation (ROSC) [2]. Among the various mechanisms implicated in the pathophysiology of secondary injury, post-resuscitation cerebral ischemia is linked to central physiologic variables that may be modifiable [3]. Observational data demonstrate associations between perturbations in physiologic variables known to reduce cerebral blood flow (CBF)—such as arterial hypotension [4] and hypocapnia [5]—and adverse clinical outcome. This adds credence to the importance of optimizing cerebral oxygen delivery, to mitigate secondary ischemic injury. Recently, sentinel randomized controlled trials (RCTs) aimed at augmenting mean arterial pressure (MAP)—a key physiologic determinant of cerebral oxygen delivery—have yielded important insights into the importance of mitigating secondary cerebral ischemia [6, 7]. Although it did not establish a definitive link to improved neurological outcome, the COMACARE study demonstrated reduced levels of neurofilament light, a biomarker of brain injury, in patients undergoing an augmented MAP strategy following ROSC [8]. Patients may continue to experience episodes of brain hypoxia following cardiac arrest, despite goal-directed therapy and augmented MAP, with considerable heterogeneity in the underlying cerebrovascular hemodynamics in individual patients [9]. Thus, a targeted approach to the individualized management of hypoxic ischemic brain injury in the post-resuscitation phase requires the longitudinal monitoring of brain oxygenation—providing clinicians with real time physiologic data points to optimize cerebral oxygen delivery, similar to that applied in patients with traumatic brain injury (TBI) [10]. Near infrared spectroscopy (NIRS) provides an easily implemented and virtually complication-free way to monitor regional cerebral oxygen saturation (rSO2) in critically ill patients. The insertion of oxygen sensing catheters provides a real time assessment of the partial pressure of oxygen in brain tissue (PbtO2). This approach has gained widespread use following neurotrauma.

In this narrative review, we discuss the available means for monitoring the occurrence of brain ischemia in patients at risk of hypoxic ischemic brain injury. Specifically, we decided to review the evidence for non-invasive monitoring, using NIRS and invasive monitoring via the insertion of tissue oxygen monitors and jugular bulb catheters. These two approaches to monitoring brain oxygenation have different advantages and limitations (Fig. 1). We also discuss ways to modify cerebral oxygenation, with a special focus on MAP and blood carbon dioxide and oxygen levels.

 

 

 

 

Measuring vitamin C in critically ill patients: clinical importance and practical difficulties—Is it time for a surrogate marker?

 

by Sander Rozemeijer, Frans A. L. van der Horst and Angélique M. E. de Man 

 

Critical Care volume 25, Article number: 310 (2021) Published: 31 August 2021

Interest in intravenous vitamin C administration has rapidly increased in the field of critical care medicine over recent years. The first studies investigating the effect of intravenous vitamin C in septic (shock) patients showed a decrease in organ dysfunction, vasopressor dependency, and even a reduction in mortality [1,2,3]. Within a short period of time, multiple trials in septic patients were conducted to confirm these promising findings, but results were not uniform [4,5,6,7,8,9,10,11,12]. The inconsistencies in effects on outcome may partially be explained by differences in study design [8], in particular the dosing regimens (timing, duration and dose) and choice of co-medication. For example, vitamin C administration has been investigated alone, or in combination with thiamine and/or hydrocortisone, sometimes with uncontrolled use of hydrocortisone in the control group. There is also considerable variety among septic patients as sepsis is a heterogeneous syndrome. Therefore, some subgroups of patients might benefit more than others from intravenous vitamin C therapy. A recently published meta-analysis on mortality performed subgroup analyses and found a beneficial effect of vitamin C on short-term mortality (< 30 days). Additionally, survival was improved by a treatment duration of 3–4 days [13]. The results of vitamin C alone versus combination therapy were not different. A particular subgroup of interest is patients with vitamin C deficiency. None of the studies performed subgroup analyses on vitamin C deficient patients. This is unfortunate, but understandable, since the measurement of plasma vitamin C concentration is difficult.

In this chapter, we discuss the practical problems and pitfalls of measuring vitamin C and describe a novel potential surrogate marker that can estimate vitamin C status.

 

A randomized controlled trial to determine whether beta-hydroxy-beta-methylbutyrate and/or eicosapentaenoic acid improves diaphragm and quadriceps strength in critically Ill mechanically ventilated patients

by Gerald S. Supinski, Paul F. Netzel, Philip M. Westgate, Elizabeth A. Schroder, Lin Wang and Leigh Ann Callahan 

Critical Care volume 25, Article number: 308 (2021) Published: 26 August 2021

Background

Intensive care unit acquired weakness is a serious problem, contributing to respiratory failure and reductions in ambulation. Currently, there is no pharmacological therapy for this condition. Studies indicate, however, that both beta-hydroxy-beta-methylbutyrate (HMB) and eicosapentaenoic acid (EPA) increase muscle function in patients with cancer and in older adults. The purpose of this study was to determine whether HMB and/or EPA administration would increase diaphragm and quadriceps strength in mechanically ventilated patients.

Methods

Studies were performed on 83 mechanically ventilated patients who were recruited from the Medical Intensive Care Units at the University of Kentucky. Diaphragm strength was assessed as the trans-diaphragmatic pressure generated by supramaximal magnetic phrenic nerve stimulation (PdiTw). Quadriceps strength was assessed as leg force generated by supramaximal magnetic femoral nerve stimulation (QuadTw). Diaphragm and quadriceps thickness were assessed by ultrasound. Baseline measurements of muscle strength and size were performed, and patients were then randomized to one of four treatment groups (placebo, HMB 3 gm/day, EPA 2 gm/day and HMB plus EPA). Strength and size measurements were repeated 11 days after study entry. ANCOVA statistical testing was used to compare variables across the four experimental groups.

Results

Treatments failed to increase the strength and thickness of either the diaphragm or quadriceps when compared to placebo. In addition, treatments also failed to decrease the duration of mechanical ventilation after study entry.

Conclusions

These results indicate that a 10-day course of HMB and/or EPA does not improve skeletal muscle strength in critically ill mechanically ventilated patients. These findings also confirm previous reports that diaphragm and leg strength in these patients are profoundly low. Additional studies will be needed to examine the effects of other anabolic agents and innovative forms of physical therapy.

 

 

 

Antimicrobial stewardship, therapeutic drug monitoring and infection management in the ICU: results from the international A- TEAMICU survey

by Christian Lanckohr, Christian Boeing, Jan J. De Waele, Dylan W. de Lange, Jeroen Schouten, Menno Prins, Maarten Nijsten, Pedro Povoa, Andrew Conway Morris and Hendrik Bracht 

Annals of Intensive Care volume 11, Article number: 131 (2021) Published: 26 August 2021

Background

Severe infections and multidrug-resistant pathogens are common in critically ill patients. Antimicrobial stewardship (AMS) and therapeutic drug monitoring (TDM) are contemporary tools to optimize the use of antimicrobials. The A-TEAMICU survey was initiated to gain contemporary insights into dissemination and structure of AMS programs and TDM practices in intensive care units.

Methods

This study involved online survey of members of ESICM and six national professional intensive care societies.

Results

Data of 812 respondents from mostly European high- and middle-income countries were available for analysis. 63% had AMS rounds available in their ICU, where 78% performed rounds weekly or more often. While 82% had local guidelines for treatment of infections, only 70% had cumulative antimicrobial susceptibility reports and 56% monitored the quantity of antimicrobials administered. A restriction of antimicrobials was reported by 62%. TDM of antimicrobial agents was used in 61% of ICUs, mostly glycopeptides (89%), aminoglycosides (77%), carbapenems (32%), penicillins (30%), azole antifungals (27%), cephalosporins (17%), and linezolid (16%). 76% of respondents used prolonged/continuous infusion of antimicrobials. The availability of an AMS had a significant association with the use of TDM.

Conclusions

Many respondents of the survey have AMS in their ICUs. TDM of antimicrobials and optimized administration of antibiotics are broadly used among respondents. The availability of antimicrobial susceptibility reports and a surveillance of antimicrobial use should be actively sought by intensivists where unavailable. Results of this survey may inform further research and educational activities.

 

Effect of awake prone position on diaphragmatic thickening fraction in patients assisted by noninvasive ventilation for hypoxemic acute respiratory failure related to novel coronavirus disease

by Gianmaria Cammarota, Elisa Rossi, Leonardo Vitali, Rachele Simonte, Tiziano Sannipoli, Francesco Anniciello, Luigi Vetrugno, Elena Bignami, Cecilia Becattini, Simonetta Tesoro, Danila Azzolina, Angelo Giacomucci, Paolo Navalesi and Edoardo De Robertis 

Critical Care volume 25, Article number: 305 (2021) Published: 24 August 2021

Background

Awake prone position is an emerging rescue therapy applied in patients undergoing noninvasive ventilation (NIV) for acute hypoxemic respiratory failure (ARF) related to novel coronavirus disease (COVID-19). Although applied to stabilize respiratory status, in awake patients, the application of prone position may reduce comfort with a consequent increase in the workload imposed on respiratory muscles. Thus, we primarily ascertained the effect of awake prone position on diaphragmatic thickening fraction, assessed through ultrasound, in COVID-19 patients undergoing NIV.

Methods

We enrolled all COVID-19 adult critically ill patients, admitted to intensive care unit (ICU) for hypoxemic ARF and undergoing NIV, deserving of awake prone positioning as a rescue therapy. Exclusion criteria were pregnancy and any contraindication to awake prone position and NIV. On ICU admission, after NIV onset, in supine position, and at 1 h following awake prone position application, diaphragmatic thickening fraction was obtained on the right side. Across all the study phases, NIV was maintained with the same setting present at study entry. Vital signs were monitored throughout the entire study period. Comfort was assessed through numerical rating scale (0 the worst comfort and 10 the highest comfort level). Data were presented in median and 25th–75th percentile range.

Results

From February to May 2021, 20 patients were enrolled and finally analyzed. Despite peripheral oxygen saturation improvement [96 (94–97)% supine vs 98 (96–99)% prone, p = 0.008], turning to prone position induced a worsening in comfort score from 7.0 (6.0–8.0) to 6.0 (5.0–7.0) (p = 0.012) and an increase in diaphragmatic thickening fraction from 33.3 (25.7–40.5)% to 41.5 (29.8–50.0)% (p = 0.025).

Conclusions

In our COVID-19 patients assisted by NIV in ICU, the application of awake prone position improved the oxygenation at the expense of a greater diaphragmatic thickening fraction compared to supine position.

 

 

Gastrointestinal bleeding in critically ill immunocompromised patients

 

by Jennifer Catano, Sophie Caroline Sacleux, Jean-Marc Gornet, Marine Camus, Naike Bigé, Faouzi Saliba, Elie Azoulay, Guillaume Dumas and Lara Zafrani 

 

Annals of Intensive Care volume 11, Article number: 130 (2021)
Open Access Published: 21 August 2021

Background

Acute gastrointestinal bleeding (GIB) may be a severe condition in immunocompromised patients and may require intensive care unit (ICU) admission. We aimed to describe the clinical spectrum of critically ill immunocompromised patients with GIB and identify risk factors associated with mortality and severe GIB defined by hemorrhagic shock, hyperlactatemia and/or the transfusion of more than 5 red blood cells units. Finally, we compared this cohort with a control population of non-immunocompromised admitted in ICU for GIB.

Results

Retrospective study in 3 centers including immunocompromised patients with GIB admitted in ICU from January, 1st 2010 to December, 31rd 2019. Risk factors for mortality and severe GIB were assessed by logistic regression. Immunocompromised patients were matched with a control group of patients admitted in ICU with GIB. A total of 292 patients were analyzed in the study, including 141 immunocompromised patients (compared to a control group of 151 patients). Among immunocompromised patients, upper GIB was more frequent (73%) than lower GIB (27%). By multivariate analysis, severe GIB was associated with male gender (OR 4.48, CI95% 1.75–11.42, p = 0.00), upper GIB (OR 2.88, CI95% 1.11–7.46, p = 0.03) and digestive malignant infiltration (OR 5.85, CI95% 1.45–23.56, p = 0.01). Conversely, proton pump inhibitor treatment before hospitalization was significantly associated with decreased risk of severe GIB (OR 0.25, IC95% 0.10–0.65, p < 0.01). Fifty-four patients (38%) died within 90 days. By multivariate analysis, mortality was associated with hemorrhagic shock (OR 2.91, IC95% 1.33–6.38, p = 0 .01), upper GIB (OR 4.33, CI95% 1.50–12.47, p = 0.01), and long-term corticosteroid therapy before admission (OR 2.98, CI95% 1.32–6.71, p = 0.01). Albuminemia (per 5 g/l increase) was associated with lower mortality (OR 0.54, IC95% 0.35–0.84, p = 0.01). After matching with a control group of non-immunocompromised patients, severity of bleeding was increased in immunocompromised patients, but mortality was not different between the 2 groups.

Conclusion

Mortality is high in immunocompromised patients with GIB in ICU, especially in patients receiving long term corticosteroids. Mortality of GIB is not different from mortality of non-immunocompromised patients in ICU. The prophylactic administration of proton pump inhibitors should be considered in this population.

 

 

Delirium in critical illness: clinical manifestations, outcomes, and management

 

Joanna L. Stollings, Katarzyna Kotfis, Gerald Chanques, Brenda T. Pun, Pratik P. Pandharipande & 

E. Wesley Ely 

 

Intensive Care Medicine: 16 August 2021

 

Delirium is the most common manifestation of brain dysfunction in critically ill patients. In the intensive care unit (ICU), duration of delirium is independently predictive of excess death, length of stay, cost of care, and acquired dementia. There are numerous neurotransmitter/functional and/or injury-causing hypotheses rather than a unifying mechanism for delirium. Without using a validated delirium instrument, delirium can be misdiagnosed (under, but also overdiagnosed and trivialized), supporting the recommendation to use a monitoring instrument routinely. The best-validated ICU bedside instruments are CAM-ICU and ICDSC, both of which also detect subsyndromal delirium. Both tools have some inherent limitations in the neurologically injured patients, yet still provide valuable information about delirium once the sequelae of the primary injury settle into a new post-injury baseline. Now it is known that antipsychotics and other psychoactive medications do not reliably improve brain function in critically ill delirious patients. ICU teams should systematically screen for predisposing and precipitating factors. These include exacerbations of cardiac/respiratory failure or sepsis, metabolic disturbances (hypoglycemia, dysnatremia, uremia and ammonemia) receipt of psychoactive medications, and sensory deprivation through prolonged immobilization, uncorrected vision and hearing deficits, poor sleep hygiene, and isolation from loved ones so common during COVID-19 pandemic. The ABCDEF (A2F) bundle is a means to facilitate implementation of the 2018 Pain, Agitation/Sedation, Delirium, Immobility, and Sleep Disruption in Adult Patients in the ICU (PADIS) Guidelines. In over 25,000 patients across nearly 100 institutions, the A2F bundle has been shown in a dose–response fashion (i.e., greater bundle compliance) to yield improved survival, length of stay, coma and delirium duration, cost, and less ICU bounce-backs and discharge to nursing homes.

 

Targeted temperature management following out-of-hospital cardiac arrest: a systematic review and network meta-analysis of temperature targets

Intensive Care Medicine: 13 August 2021

 

Purpose

Targeted temperature management (TTM) may improve survival and functional outcome in comatose survivors of out-of-hospital cardiac arrest (OHCA), though the optimal target temperature remains unknown. We conducted a systematic review and network meta-analysis to investigate the efficacy and safety of deep hypothermia (31–32 °C), moderate hypothermia (33–34 °C), mild hypothermia (35–36 °C), and normothermia (37–37.8 °C) during TTM.

Methods

We searched six databases from inception to June 2021 for randomized controlled trials (RCTs) evaluating TTM in comatose OHCA survivors. Two reviewers performed screening, full text review, and extraction independently. The primary outcome of interest was survival with good functional outcome. We used GRADE to rate our certainty in estimates.

Results

We included 10 RCTs (4218 patients). Compared with normothermia, deep hypothermia (odds ratio [OR] 1.30, 95% confidence interval [CI] 0.73–2.30), moderate hypothermia (OR 1.34, 95% CI 0.92–1.94) and mild hypothermia (OR 1.44, 95% CI 0.74–2.80) may have no effect on survival with good functional outcome (all low certainty). Deep hypothermia may not improve survival with good functional outcome, as compared to moderate hypothermia (OR 0.97, 95% CI 0.61–1.54, low certainty). Moderate hypothermia (OR 1.23, 95% CI 0.86–1.77) and deep hypothermia (OR 1.27, 95% CI 0.70–2.32) may have no effect on survival, as compared to normothermia. Finally, incidence of arrhythmia was higher with moderate hypothermia (OR 1.45, 95% CI 1.08–1.94) and deep hypothermia (OR 3.58, 95% CI 1.77–7.26), compared to normothermia (both high certainty).

Conclusions

Mild, moderate, or deep hypothermia may not improve survival or functional outcome after OHCA, as compared to normothermia. Moderate and deep hypothermia were associated with higher incidence of arrhythmia. Routine use of moderate or deep hypothermia in comatose survivors of OHCA may potentially be associated with more harm than benefit.

 

 

How COVID-19 will change the management of other respiratory viral infections

 Yaseen M. Arabi, Lennie P. G. Derde & Jean-François Timsit 

Intensive Care Medicine:  11 August 2021

Started with a local outbreak of pneumonia in Wuhan, China, coronavirus disease-19 (COVID-19) has spread globally over a short time, to become one of the largest known pandemic in human history. In parallel, and within less than a year and a half, there have been great advancements in understanding the pathophysiology, management, and prevention of COVID-19. The speed of progress has far exceeded what has been made in many other diseases, including other severe respiratory viral infections (RVIs). This progress was driven largely by the pressing urgency created by the unprecedented global pandemic. However, at the same time, many advancements would not have been possible without the coordinated research response; a response that has built on knowledge and networks already present.

While we are still in the midst of the COVID-19 pandemic, and there is much to learn about this disease, the experience from COVID-19 should transform the approach to addressing future research on RVIs. There are many biologic similarities and differences between COVID-19 and other RVIs, which translate to similarities and differences in management. Here, we focus on selected lessons learned in COVID-19 management and how they may be relevant for research in other RVIs (Fig. 1; Table S1)…

 

Intensive care doctors and nurses personal preferences for Intensive Care, as compared to the general population: a discrete choice experiment

 by Matthew H. Anstey, Imogen A. Mitchell, Charlie Corke, Lauren Murray, Marion Mitchell, Andrew Udy, Vineet Sarode, Nhi Nguyen, Oliver Flower, Kwok M. Ho, Edward Litton, Bradley Wibrow and Richard Norman 

 Critical Care volume 25, Article number: 287 (2021) Published: 10 August 2021

 Background

To test the hypothesis that Intensive Care Unit (ICU) doctors and nurses differ in their personal preferences for treatment from the general population, and whether doctors and nurses make different choices when thinking about themselves, as compared to when they are treating a patient.

Methods

Cross sectional, observational study conducted in 13 ICUs in Australia in 2017 using a discrete choice experiment survey. Respondents completed a series of choice sets, based on hypothetical situations which varied in the severity or likelihood of: death, cognitive impairment, need for prolonged treatment, need for assistance with care or requiring residential care.

Results

A total of 980 ICU staff (233 doctors and 747 nurses) participated in the study. ICU staff place the highest value on avoiding ending up in a dependent state. The ICU staff were more likely to choose to discontinue therapy when the prognosis was worse, compared with the general population. There was consensus between ICU staff personal views and the treatment pathway likely to be followed in 69% of the choices considered by nurses and 70% of those faced by doctors. In 27% (1614/5945 responses) of the nurses and 23% of the doctors (435/1870 responses), they felt that aggressive treatment would be continued for the hypothetical patient but they would not want that for themselves.

Conclusion

The likelihood of returning to independence (or not requiring care assistance) was reported as the most important factor for ICU staff (and the general population) in deciding whether to receive ongoing treatments. Goals of care discussions should focus on this, over likelihood of survival.

 

 

Association between sepsis survivorship and long-term cardiovascular outcomes in adults: a systematic review and meta-analysis

Intensive Care Medicine: Published: 09 August 2021

Purpose

We aimed to determine the association between sepsis and long-term cardiovascular events.

Methods

We conducted a systematic review of observational studies evaluating post-sepsis cardiovascular outcomes in adult sepsis survivors. MEDLINE, Embase, and the Cochrane Controlled Trials Register and Database of Systematic Reviews were searched from inception until April 21st, 2021. Two reviewers independently extracted individual study data and evaluated risk of bias. Random-effects models estimated the pooled crude cumulative incidence and adjusted hazard ratios (aHRs) of cardiovascular events compared to either non-septic hospital survivors or population controls. Primary outcomes included myocardial infarction, stroke, and congestive heart failure; outcomes were analysed at maximum reported follow-up (from 30 days to beyond 5 years post-discharge).

Results

Of 12,649 screened citations, 27 studies (25 cohort studies, 2 case-crossover studies) were included with a median of 4,289 (IQR 502–68,125) sepsis survivors and 18,399 (IQR 4,028–83,506) controls per study. The pooled cumulative incidence of myocardial infarction, stroke, and heart failure in sepsis survivors ranged from 3 to 9% at longest reported follow-up. Sepsis was associated with a higher long-term risk of myocardial infarction (aHR 1.77 [95% CI 1.26 to 2.48]; low certainty), stroke (aHR 1.67 [95% CI 1.37 to 2.05]; low certainty), and congestive heart failure (aHR 1.65 [95% CI 1.46 to 1.86]; very low certainty) compared to non-sepsis controls.

Conclusions

Surviving sepsis may be associated with a long-term, excess hazard of late cardiovascular events which may persist for at least 5 years following hospital discharge.

 

P/FP ratio: incorporation of PEEP into the PaO2/FiO2 ratio for prognostication and classification of acute respiratory distress syndrome

by Sunitha Palanidurai, Jason Phua, Yiong Huak Chan and Amartya Mukhopadhyay 

 

Annals of Intensive Care: Published: 09 August 2021

 

Background

The current Berlin definition of acute respiratory distress syndrome (ARDS) uses the PaO2/FiO2 (P/F) ratio to classify severity. However, for the same P/F ratio, a patient on a higher positive end-expiratory pressure (PEEP) may have more severe lung injury than one on a lower PEEP.

Objectives

We designed a new formula, the P/FP ratio, incorporating PEEP into the P/F ratio and multiplying with a correction factor of 10 [(PaO2*10)/(FiO2*PEEP)], to evaluate if it better predicts hospital mortality compared to the P/F ratio post-intubation and to assess the resultant changes in severity classification of ARDS.

Methods

We categorized patients from a dataset of seven ARDS network trials using the thresholds of ≤ 100 (severe), 101–200 (moderate), and 201–300 (mild) for both P/F (mmHg) and P/FP (mmHg/cmH2O) ratios and evaluated hospital mortality using areas under the receiver operating characteristic curves (AUC).

Results

Out of 3,442 patients, 1,057 (30.7%) died. The AUC for mortality was higher for the P/FP ratio than the P/F ratio for PEEP levels > 5 cmH2O: 0.710 (95% CI 0.691–0.730) versus 0.659 (95% CI 0.637–0.681), P < 0.001. Improved AUC was seen with increasing PEEP levels; for PEEP ≥ 18 cmH2O: 0.963 (95% CI 0.947–0.978) versus 0.828 (95% CI 0.765–0.891), P < 0.001. When the P/FP ratio was used instead of the P/F ratio, 12.5% and 15% of patients with moderate and mild ARDS, respectively, were moved to more severe categories, while 13.9% and 33.6% of patients with severe and moderate ARDS, respectively, were moved to milder categories. The median PEEP and FiO2 were 14 cmH2O and 0.70 for patients reclassified to severe ARDS, and 5 cmH2O and 0.40 for patients reclassified to mild ARDS.

Conclusions

The multifactorial P/FP ratio has a greater predictive validity for hospital mortality in ARDS than the P/F ratio. Changes in severity classification with the P/FP ratio reflect both true illness severity and the applied PEEP strategy.