Low Tidal Volume Ventilation Use in Acute Respiratory Distress Syndrome

Open-source machine learning pipeline automatically flags instances of acute respiratory distress syndrome from electronic health records

Physicians could greatly benefit from automated diagnosis and prognosis tools to help address information overload and decision fatigue. Intensive care physicians stand to benefit greatly from such tools as they are at particularly high risk for those factors. Acute Respiratory Distress Syndrome (ARDS) is a life-threatening condition affecting >10% of critical care patients and has a mortality rate over 40%. However, recognition rates for ARDS have been shown to be low (30-70%) in clinical settings. In this work, we present a reproducible computational pipeline that automatically adjudicates ARDS on retrospective datasets of mechanically ventilated adult patients. This pipeline automates the steps outlined by the Berlin Definition through implementation of natural language processing tools and classification algorithms. We train an XGBoost model on chest imaging reports to detect bilateral infiltrates, and another on a subset of attending physician notes labeled for the most common ARDS risk factor in our data. Both models achieve high performance-a minimum area under the receiver operating characteristic curve (AUROC) of 0.86 for adjudicating chest imaging reports in out-of-bag test sets, and an out-of-bag AUROC of 0.85 for detecting a diagnosis of pneumonia. We validate the entire pipeline on a cohort of MIMIC-III encounters and find a sensitivity of 93.5% - an extraordinary improvement over the 22.6% ARDS recognition rate reported for these encounters - along with a specificity of 73.9%. We conclude that our reproducible, automated diagnostic pipeline exhibits promising accuracy, generalizability, and probability calibration, thus providing a valuable resource for physicians aiming to enhance ARDS diagnosis and treatment strategies. We surmise that proper implementation of the pipeline has the potential to aid clinical practice by facilitating the recognition of ARDS cases at scale.

Acute Respiratory Distress Syndrome: Definition, Diagnosis, and Routine Management

Acute respiratory distress syndrome (ARDS) is an acute inflammatory lung injury characterized by severe hypoxemic respiratory failure, bilateral opacities on chest imaging, and low lung compliance. ARDS is a heterogeneous syndrome that is the common end point of a wide variety of predisposing conditions, with complex pathophysiology and underlying mechanisms. Routine management of ARDS is centered on lung-protective ventilation strategies such as low tidal volume ventilation and targeting low airway pressures to avoid exacerbation of lung injury, as well as a conservative fluid management strategy.

Eye on the Prize: Patient Outcomes Research in Medical Education

The overarching goal of medical education is to train clinicians who achieve and maintain competence in patient care. Although the field of medical education research has acknowledged the importance of education on clinical practices and outcomes, most research endeavors continue to focus on learner-centered outcomes, such as knowledge and attitudes. The absence of clinical and patient-centered outcomes in pulmonary and critical care medicine medical education research has been attributed to barriers at multiple levels, including financial, methodological, and practical considerations. This Perspective explores clinical outcomes relevant to pulmonary and critical care medicine educational research and offers strategies and solutions that educators can use to accomplish what many consider the "prize" of medical education research: an understanding of how our educational initiatives impact the health of patients.

Long short-term memory model identifies ARDS and in-hospital mortality in both non-COVID-19 and COVID-19 cohort

OBJECTIVE

To identify the risk of acute respiratory distress syndrome (ARDS) and in-hospital mortality using long short-term memory (LSTM) framework in a mechanically ventilated (MV) non-COVID-19 cohort and a COVID-19 cohort.

METHODS

We included MV ICU patients between 2017 and 2018 and reviewed patient records for ARDS and death. Using active learning, we enriched this cohort with MV patients from 2016 to 2019 (MV non-COVID-19, n=3905). We collected a second validation cohort of hospitalised patients with COVID-19 in 2020 (COVID+, n=5672). We trained an LSTM model using 132 structured features on the MV non-COVID-19 training cohort and validated on the MV non-COVID-19 validation and COVID-19 cohorts.

RESULTS

Applying LSTM (model score 0.9) on the MV non-COVID-19 validation cohort had a sensitivity of 86% and specificity of 57%. The model identified the risk of ARDS 10 hours before ARDS and 9.4 days before death. The sensitivity (70%) and specificity (84%) of the model on the COVID-19 cohort are lower than MV non-COVID-19 cohort. For the COVID-19 + cohort and MV COVID-19 + patients, the model identified the risk of in-hospital mortality 2.4 days and 1.54 days before death, respectively.

DISCUSSION

Our LSTM algorithm accurately and timely identified the risk of ARDS or death in MV non-COVID-19 and COVID+ patients. By alerting the risk of ARDS or death, we can improve the implementation of evidence-based ARDS management and facilitate goals-of-care discussions in high-risk patients.

CONCLUSION

Using the LSTM algorithm in hospitalised patients identifies the risk of ARDS or death.

Validation of a tool for estimating clinician recognition of ARDS using data from the international LUNG SAFE study

Under-recognition of acute respiratory distress syndrome (ARDS) by clinicians is an important barrier to adoption of evidence-based practices such as low tidal volume ventilation. The burden created by the COVID-19 pandemic makes it even more critical to develop scalable data-driven tools to improve ARDS recognition. The objective of this study was to validate a tool for accurately estimating clinician ARDS recognition rates using discrete clinical characteristics easily available in electronic health records. We conducted a secondary analysis of 2,705 ARDS and 1,261 non-ARDS hypoxemic patients in the international LUNG SAFE cohort. The primary outcome was validation of a tool that estimates clinician ARDS recognition rates from health record data. Secondary outcomes included the relative impact of clinical characteristics on tidal volume delivery and clinician documentation of ARDS. In both ARDS and non-ARDS patients, greater height was associated with lower standardized tidal volume (mL/kg PBW) (ARDS: adjusted β = -4.1, 95% CI -4.5 --3.6; non-ARDS: β = -7.7, 95% CI -8.8 --6.7, P<0.00009 [where α = 0.01/111 with the Bonferroni correction]). Standardized tidal volume has already been normalized for patient height, and furthermore, height was not associated with clinician documentation of ARDS. Worsening hypoxemia was associated with both increased clinician documentation of ARDS (β = -0.074, 95% CI -0.093 --0.056, P<0.00009) and lower standardized tidal volume (β = 1.3, 95% CI 0.94-1.6, P<0.00009) in ARDS patients. Increasing chest imaging opacities, plateau pressure, and clinician documentation of ARDS also were associated with lower tidal volume in ARDS patients. Our EHR-based data-driven approach using height, gender, ARDS documentation, and lowest standardized tidal volume yielded estimates of clinician ARDS recognition rates of 54% for mild, 63% for moderate, and 73% for severe ARDS. Our tool replicated clinician-reported ARDS recognition in the LUNG SAFE study, enabling the identification of ARDS patients at high risk of being unrecognized. Our approach can be generalized to other conditions for which there is a need to increase adoption of evidence-based care.

A Pilot Standardized Simulation-Based Mechanical Ventilation Curriculum Targeting Pulmonary and Critical Care Medicine and Critical Care Medicine Fellows

Introduction  The mastery of mechanical ventilation (MV) management is challenging, as it requires the integration of physiological and technological knowledge with critical thinking. Our aim was to create a standardized curriculum with assessment tools based on evidence-based practices to identify the skill deficit and improve knowledge in MV management. Methods  For 3 years, 3 hours of standardized curriculum for each first-year pulmonary critical care medicine (PCCM) and critical care medicine (CCM) fellows was integrated into the orientation (chronologically): (1) a baseline knowledge pretest; (2) a 1-hour one-on-one case-based simulation session with debriefing. A 34-item competency checklist was used to assess critically thinking and skills and guide the debriefing; (3) a 1-hour group didactic on respiratory mechanics and physiology; (4) a 45-minute hands-on session in small groups of one to three fellows for basic knobology, waveforms, and various modes of mechanical ventilators; (5) a 15-minute group bedside teaching of vented patients covering topics such as techniques to alleviate dyssynchrony and advanced ventilator modes; (6) a one-on-one simulation reassessment session; (7) a knowledge posttest. Fellows' performances at baseline, 1-month posttest, and end-of-first year post-test were compared. Results  Fellows ( n  = 24) demonstrated significant improvement at 1-month posttest in knowledge (54.2% ± 11.0 vs. 76.6 ± 11.7%, p  < 0.001) and MV competency (40.7 ± 11.0% vs. 69.7 ± 9.3%, p  < 0.001), compared with pretest. These improvements were retained at the end-of-year reassessments (knowledge 75.1 ± 14.5% and MV competency 85.5 ± 8.7%; p  < 0.001). Conclusion  Standardized simulation-based MV curriculum may improve the medical knowledge competency, and confidence of first-year PCCM and CCM fellows toward MV management before encountering actual ventilated patients.

Delivery of Lung-protective Ventilation for Acute Respiratory Distress Syndrome: A Hybrid Implementation-Effectiveness Trial

Rationale: Lung-protective ventilation (LPV) improves outcomes for patients with acute respiratory distress syndrome (ARDS), but adherence remains inadequate. Objectives: To measure the process and clinical impacts of implementation of a science-based intervention to improve LPV adherence for patients with ARDS, in part by increased use of clinical decision support (CDS). Methods: We conducted a type III hybrid implementation/effectiveness pilot trial enrolling adult patients with ARDS admitted to three hospitals before and after the launch of a multimodal implementation intervention to increase the use of mechanical ventilation CDS and improve LPV adherence. The primary outcome was patients' percentage of time adherent to low tidal volume (⩽6.5 ml/kg predicted body weight) ventilation (LTVV). Secondary outcomes included adherence to prescribed oxygenation settings, the use of the CDS tool's independent oxygenation and ventilation components, ventilator-free days, and mortality. Analyses employed multivariable regression to compare adjusted pre- versus postintervention outcomes after the exclusion of a postintervention wash-in period. A sensitivity analysis measured process outcomes' level and trend change postintervention using segmented regression. Results: The 446 included patients had a mean age of 60 years, and 43% were female. Demographic and clinical characteristics were similar pre- versus postintervention. The adjusted proportion of adherent time increased postintervention for LTVV (9.2%; 95% confidence interval [CI], 3.8-14.5%) and prescribed oxygenation settings (11.9%; 95% CI, 7.2-16.5%), as did the probability patients spent ⩾90% of ventilated time on LTVV (adjusted odds ratio [aOR] 2.58; 95% CI, 1.64-4.10) and use of ventilation CDS (aOR, 41.3%; 95% CI, 35.9-46.7%) and oxygenation CDS (aOR, 54.3%; 95% CI, 50.9-57.7%). Ventilator-free days (aOR, 1.15; 95% CI, 0.81-1.62) and 28-day mortality (aOR, 0.78; 95% CI, 0.50-1.20) did not change significantly after intervention. Segmented regression analysis supported a causal relationship between the intervention and improved CDS usage but suggested trends before intervention rather than the studied intervention could explain increased LPV adherence after the intervention. Conclusions: In this pilot trial, a multimodal implementation intervention was associated with increased use of ventilator management CDS for patients with ARDS but was not associated with differences in clinical outcomes and may not have independently caused the observed postintervention improvements in LPV adherence. Clinical trial registered with www.clinicaltrials.gov (NCT03984175).

Driving Pressure, Elastance, and Outcomes in a Real-World Setting: A Bi-Center Analysis of Electronic Health Record Data

Emerging evidence suggests the potential importance of inspiratory driving pressure (DP) and respiratory system elastance (E_RS) on outcomes among patients with the acute respiratory distress syndrome. Their association with outcomes among heterogeneous populations outside of a controlled clinical trial is underexplored. We used electronic health record (EHR) data to characterize the associations of DP and E_RS with clinical outcomes in a real-world heterogenous population.

DESIGN

Observational cohort study.

SETTING

Fourteen ICUs in two quaternary academic medical centers.

PATIENTS

Adult patients who received mechanical ventilation for more than 48 hours and less than 30 days.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

EHR data from 4,233 ventilated patients from 2016 to 2018 were extracted, harmonized, and merged. A minority of the analytic cohort (37%) experienced a Pao₂/Fio₂ of less than 300. A time-weighted mean exposure was calculated for ventilatory variables including tidal volume (V_T), plateau pressures (P_PLAT), DP, and E_RS. Lung-protective ventilation adherence was high (94% with V_T < 8.5 mL/kg, time-weighted mean V_T = 6. 8 mL/kg, 88% with P_PLAT ≤ 30 cm H₂O). Although time-weighted mean DP (12.2 cm H₂O) and E_RS (1.9 cm H₂O/[mL/kg]) were modest, 29% and 39% of the cohort experienced a DP greater than 15 cm H₂O or an E_RS greater than 2 cm H₂O/(mL/kg), respectively. Regression modeling with adjustment for relevant covariates determined that exposure to time-weighted mean DP (> 15 cm H₂O) was associated with increased adjusted risk of mortality and reduced adjusted ventilator-free days independent of adherence to lung-protective ventilation. Similarly, exposure to time-weighted mean E_RS greater than 2 cm H₂O/(mL/kg) was associated with increased adjusted risk of mortality.

CONCLUSIONS

Elevated DP and E_RS are associated with increased risk of mortality among ventilated patients independent of severity of illness or oxygenation impairment. EHR data can enable assessment of time-weighted ventilator variables and their association with clinical outcomes in a multicenter real-world setting.

Hospital Variation in Mortality and Ventilator Management among Mechanically Ventilated Patients with ARDS

RATIONALE

Acute Respiratory Distress Syndrome (ARDS) is associated with significant mortality. Despite the mortality benefits of lung protective ventilation, adherence rates to evidence-based ventilator practice have remained low and ARDS mortality has remained high.

OBJECTIVE

Determine variation in ARDS mortality and adherence to low tidal volume ventilation (LTV) across US hospitals.

MATERIALS AND METHODS

We identified mechanically ventilated patients with ARDS using data from Philips eICU (2014-2015). We then used multi-variable hierarchical logistic regression models with hospital site as the random effect and patient and hospital level factors as fixed effects to assess the hospital risk adjusted mortality rate and median odds ratio for the association between mortality and hospital site. We then assessed associations between adherence to LTV (defined as 4-8 mL/kg PBW) and hospital risk adjusted mortality rates using Spearman correlation.

RESULTS

Among 4441 patients admitted at 110 hospitals with ARDS, the hospital risk-adjusted mortality rate ranged from 19% to 39%, and the MOR for hospital of admission was 1.33 (95% CI 1.25-1.41). Among 3070 patients at 72 hospitals with available ventilator data, 73% of patients had a median set Vt between 4 to 8 mL/kg PBW; hospital adherence rates to LTV ranged from 13% to 95%. There was no association between hospital adherence to LTV and risk-adjusted mortality rate (spearman correlation coefficient -0.01, p = .93). Similarly, among 956 patients who started with a Vt > 8 mL/kg PBW, there was no association between the percent of patients at each hospital whose Vt was decreased to ≤ 8 mL/kg PBW and risk adjusted mortality rate (spearman correlation coefficient .05, p = .73).

CONCLUSION

Risk adjusted mortality and use of LTV for patients with ARDS varied widely across hospitals. However, hospital adherence to LTV was not associated with ARDS mortality rates. Further evaluation of hospital practices associated with lower ARDS mortality are warranted.

Angiotensin-(1-7) alleviates acute lung injury by activating the Mas receptor in neutrophil

Background

Acute lung injury (ALI) is a major cause of mortality and morbidity in the clinic. None of the current pharmacological interventions has achieved a detectable benefit. The renin-angiotensin system (RAS) is a complex humoral system essentially involved in the regulation of ALI. In the RAS family, angiotensin (Ang)-(1-7) was found to provide protection by counteracting the effects of Ang II in various cardiopulmonary disease models. The downstream receptor of Ang-(1-7) is the G protein-coupled receptor (GPCR) Mas. We hypothesize that the Ang-(1-7)-Mas pathway would protect patients from ALI.

Methods

To establish a 2-hit ALI model, the mice underwent intratracheal instillation of hydrochloric acid followed by ventilator-induced lung injury (VILI). ALI was evaluated based on lung edema, histology, myeloperoxidase activity, and proinflammatory cytokine production. The effects of the infusion or inhalation of Ang-(1-7) and Mas receptor blocker A779 were examined. The human neutrophils were isolated, and Mas receptor expression was examined. The neutrophil responses to platelet-activating factor (PAF) stimulation were tested by measuring the formation of reactive oxygen species (ROS), neutrophil adhesion, and chemotaxis. Next, in the mouse model, the neutrophils were depleted using an anti-ly6G antibody.

Results

The infusion or inhalation of Ang-(1-7) protected mice from ALI as evidenced by decreases in lung edema, the histological lung injury score, myeloperoxidase activity, and proinflammatory cytokine production. Such effects were largely blocked by the Mas receptor blocker A779. Mas receptor expression in the neutrophils was identified at both the messenger ribonucleic acid and protein levels. Ang-(1-7) prevented neutrophil responses to PAF stimulation, including the formation of ROS, neutrophil adhesion, and chemotaxis, while A779 alleviated these effects. The importance of neutrophils in ALI was further confirmed by neutrophil depletion using the anti-ly6G antibody; however, A779 partially reversed the protective role of neutrophil depletion in ALI, indicating the critical role of Ang-(1-7)-Mas signaling in other pulmonary cells.

Conclusions

Ang-(1-7)/Mas receptor attenuates the key features of ALI by regulating neutrophil activation. Our study provides new evidence of their role in the pathogenesis of ALI and may lead to the development of a promising therapeutic strategy.

Intermediate tidal volume is an acceptable option for ventilated patients with acute respiratory distress syndrome

Objective

Evidence only proves low surpasses high tidal volume (V _T) for acute respiratory distress syndrome (ARDS). Intermediate V _T is a common setting for ARDS patients and has been demonstrated as effective as low V _T in non-ARDS patients. The effectiveness of intermediate V _T in ARDS has not been studied and is the objective of this study.

Design

A retrospective cohort study.

Setting

Five ICUs with their totally 130 beds in Taiwan.

Patients or participants

ARDS patients under invasive ventilation.

Interventions

No.

Main variables of interest

28-D mortality.

Result

Totally 382 patients, with 6958 ventilator settings eligible for lung protection, were classified into low (mean V _T = 6.7 ml/kg), intermediate (mean V _T = 8.9 ml/kg) and high (mean V _T = 11.2 ml/kg) V _T groups. With similar baseline ARDS and ICU severities, intermediate and low V _T groups did not differ in 28-D mortality (47% vs. 63%, P = 0.06) or other outcomes such as 90-D mortality, ventilator-free days, ventilator-dependence rate. Multivariate analysis revealed high V _T was independently associated with 28-D and 90-D mortality, but intermediate V _T was not significantly associated with 28-D mortality (HR 1.34, CI 0.92-1.97, P = 0.13) or 90-D mortality. When the intermediate and low V _T groups were matched in propensity scores (n = 66 for each group), their outcomes were also not significantly different.

Conclusion

Intermediate V _T, with its outcomes similar to small V _T, is an acceptable option for ventilated ARDS patients. This conclusion needs verification through clinical trials.

Secondary use of data extracted from a clinical information system to assess the adherence of tidal volume and its impact on outcomes

OBJECTIVES

To extract data from clinical information systems to automatically calculate high-resolution quality indicators to assess adherence to recommendations for low tidal volume.

DESIGN

We devised two indicators: the percentage of time under mechanical ventilation with excessive tidal volume (>8mL/kg predicted body weight) and the percentage of patients who received appropriate tidal volume (≤8mL/kg PBW) at least 80% of the time under mechanical ventilation. We developed an algorithm to automatically calculate these indicators from clinical information system data and analyzed associations between them and patients' characteristics and outcomes.

SETTINGS

This study has been carried out in our 30-bed polyvalent intensive care unit between January 1, 2014 and November 30, 2019.

PATIENTS

All patients admitted to intensive care unit ventilated >72h were included.

INTERVENTION

Use data collected automatically from the clinical information systems to assess adherence to tidal volume recommendations and its outcomes.

MAIN VARIABLES OF INTEREST

Mechanical ventilation days, ICU length of stay and mortality.

RESULTS

Of all admitted patients, 340 met the inclusion criteria. Median percentage of time under mechanical ventilation with excessive tidal volume was 70% (23%-93%); only 22.3% of patients received appropriate tidal volume at least 80% of the time. Receiving appropriate tidal volume was associated with shorter duration of mechanical ventilation and intensive care unit stay. Patients receiving appropriate tidal volume were mostly male, younger, taller, and less severely ill. Adjusted intensive care unit mortality did not differ according to percentage of time with excessive tidal volume or to receiving appropriate tidal volume at least 80% of the time.

CONCLUSIONS

Automatic calculation of process-of-care indicators from clinical information systems high-resolution data can provide an accurate and continuous measure of adherence to recommendations. Adherence to tidal volume recommendations was associated with shorter duration of mechanical ventilation and intensive care unit stay.

Low tidal volume ventilation alleviates ventilator-induced lung injury by regulating the NLRP3 inflammasome

PURPOSE

Low tidal volume ventilation (LTVV) is a well-known ventilation mode which can improve ventilator-induced lung injury (VILI). However, the mechanism of LTVV ameliorating VILI has not yet been elucidated. In this study, we aimed to reveal LTVV protected against VILI by inhibiting the activation of the NLRP3 inflammasome in bronchoalveolar lavage fluid (BALF) from humans and lungs from mice.

MATERIALS AND METHODS

Twenty-eight patients scheduled for video-assisted thoracoscopic esophagectomy were randomized to receive high-tidal-volume ventilation [V_t = 10 mL/kg without positive end-expiratory pressure (PEEP)] or LTVV (V_t = 5 mL/kg along with 5 cm of H₂O PEEP) during one-lung ventilation. BALF was collected before and at the end of surgery. Male C57BL/6 mice received high-tidal-volume ventilation, LTVV or MCC950 (an inhibitor of NLRP3). The activation of the formation of NLRP3 inflammasome in BALF from patients and in lungs from mice were analyzed.

RESULTS

LTTV decreased the peak airway pressure (P_peak), plateau airway pressure (P_plat) and driving pressure (ΔP) during one-lung ventilation. Additionally, LTVV not only inhibited pulmonary infiltration and inflammation caused by mechanical ventilation, but also suppressed the NLRP3 inflammasome activation in BALF from humans. In mice, ventilator-induced inflammatory response and pulmonary edema were suppressed by LTVV with an efficacy comparable to that of MCC950 treatment. Furthermore, LTVV, similar to MCC950, clearly decreased ventilator-induced NLRP3 inflammasome activation.

CONCLUSION

Our study showed that LTVV played a protective role in ventilator-induced lung injury by suppressing the activation of the NLRP3 inflammasome.

TRIAL REGISTRATION

This study was registered in The Chinese Clinical Trial Registry, ChiCTR1900026190 on 25 September 2019.

Use of a Portable Electronic Interface Improves Clinical Handoffs and Adherence to Lung Protective Ventilation

Background

Methods

Results

Conclusion

The first step is recognizing there is a problem: a methodology for adjusting for variability in disease severity when estimating clinician performance

Background

Adoption of innovations in the field of medicine is frequently hindered by a failure to recognize the condition targeted by the innovation. This is particularly true in cases where recognition requires integration of patient information from different sources, or where disease presentation can be heterogeneous and the recognition step may be easier for some patients than for others.

Methods

We propose a general data-driven metric for clinician recognition that accounts for the variability in patient disease severity and for institutional standards. As a case study, we evaluate the ventilatory management of 362 patients with acute respiratory distress syndrome (ARDS) at a large academic hospital, because clinician recognition of ARDS has been identified as a major barrier to adoption to evidence-based ventilatory management. We calculate our metric for the 48 critical care physicians caring for these patients and examine the relationships between differences in ARDS recognition performance from overall institutional levels and provider characteristics such as demographics, social network position, and self-reported barriers and opinions.

Results

Our metric was found to be robust to patient characteristics previously demonstrated to affect ARDS recognition, such as disease severity and patient height. Training background was the only factor in this study that showed an association with physician recognition. Pulmonary and critical care medicine (PCCM) training was associated with higher recognition (β = 0.63, 95% confidence interval 0.46–0.80, p < 7 × 10^− 5). Non-PCCM physicians recognized ARDS cases less frequently and expressed greater satisfaction with the ability to get the information needed for making an ARDS diagnosis (p < 5 × 10^− 4), suggesting that lower performing clinicians may be less aware of institutional barriers.

Conclusions

We present a data-driven metric of clinician disease recognition that accounts for variability in patient disease severity and for institutional standards. Using this metric, we identify two unique physician populations with different intervention needs. One population consistently recognizes ARDS and reports barriers vs one does not and reports fewer barriers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-022-01543-7.

Hospital Variation in Management and Outcomes of Acute Respiratory Distress Syndrome Due to COVID-19

OBJECTIVES

To describe hospital variation in use of "guideline-based care" for acute respiratory distress syndrome (ARDS) due to COVID-19.

DESIGN

Retrospective, observational study.

SETTING

The Society of Critical Care Medicine's Discovery Viral Infection and RESPIRATORY ILLNESS UNIVERSAL STUDY COVID-19 REGISTRY.

PATIENTS

Adult patients with ARDS due to COVID-19 between February 15, 2020, and April 12, 2021.

INTERVENTIONS

Hospital-level use of "guideline-based care" for ARDS including low-tidal-volume ventilation, plateau pressure less than 30 cm H₂O, and prone ventilation for a Pao₂/Fio₂ ratio less than 100.

MEASUREMENTS AND MAIN RESULTS

Among 1,495 adults with COVID-19 ARDS receiving care across 42 hospitals, 50.4% ever received care consistent with ARDS clinical practice guidelines. After adjusting for patient demographics and severity of illness, hospital characteristics, and pandemic timing, hospital of admission contributed to 14% of the risk-adjusted variation in "guideline-based care." A patient treated at a randomly selected hospital with higher use of guideline-based care had a median odds ratio of 2.0 (95% CI, 1.1-3.4) for receipt of "guideline-based care" compared with a patient receiving treatment at a randomly selected hospital with low use of recommended therapies. Median-adjusted inhospital mortality was 53% (interquartile range, 47-62%), with a nonsignificantly decreased risk of mortality for patients admitted to hospitals in the highest use "guideline-based care" quartile (49%) compared with the lowest use quartile (60%) (odds ratio, 0.7; 95% CI, 0.3-1.9; p = 0.49).

CONCLUSIONS

During the first year of the COVID-19 pandemic, only half of patients received "guideline-based care" for ARDS management, with wide practice variation across hospitals. Strategies that improve adherence to recommended ARDS management strategies are needed.

Improving delivery of low tidal volume ventilation in 10 ICUs

Low tidal volume ventilation (LTVV) is standard of care for mechanically ventilated patients with acute respiratory distress syndrome and has been shown to improve outcomes in the general mechanically ventilated population. Despite these improved outcomes, in clinical practice the LTVV standard of care is often not met. We aimed to increase compliance with LTVV in mechanically ventilated patients in 10 intensive care units at 3 hospitals within the University of Pittsburgh School of Medicine Department of Critical Care Medicine. Four Plan-Do-Study-Act (PDSA) cycles were implemented to improve compliance with LTVV. Initial compliance rates of 40.6%–60.1% improved to 91%–96% by the end of the fourth PDSA cycle. The most impactful step in the intervention was providing education and giving responsibility of selecting the tidal volume to the respiratory therapist. The overall intervention resulted in improved compliance with LTVV that has been sustained for multiple years after our active PDSA cycles.

Research Needs for Inpatient Management of Severe Alcohol Withdrawal Syndrome: An Official American Thoracic Society Research Statement

Background: Severe alcohol withdrawal syndrome (SAWS) is highly morbid, costly, and common among hospitalized patients, yet minimal evidence exists to guide inpatient management. Research needs in this field are broad, spanning the translational science spectrum. Goals: This research statement aims to describe what is known about SAWS, identify knowledge gaps, and offer recommendations for research in each domain of the Institute of Medicine T0-T4 continuum to advance the care of hospitalized patients who experience SAWS. Methods: Clinicians and researchers with unique and complementary expertise in basic, clinical, and implementation research related to unhealthy alcohol consumption and alcohol withdrawal were invited to participate in a workshop at the American Thoracic Society 2019 International Conference. The committee was subdivided into four groups on the basis of interest and expertise: T0-T1 (basic science research with translation to humans), T2 (research translating to patients), T3 (research translating to clinical practice), and T4 (research translating to communities). A medical librarian conducted a pragmatic literature search to facilitate this work, and committee members reviewed and supplemented the resulting evidence, identifying key knowledge gaps. Results: The committee identified several investigative opportunities to advance the care of patients with SAWS in each domain of the translational science spectrum. Major themes included 1) the need to investigate non-γ-aminobutyric acid pathways for alcohol withdrawal syndrome treatment; 2) harnessing retrospective and electronic health record data to identify risk factors and create objective severity scoring systems, particularly for acutely ill patients with SAWS; 3) the need for more robust comparative-effectiveness data to identify optimal SAWS treatment strategies; and 4) recommendations to accelerate implementation of effective treatments into practice. Conclusions: The dearth of evidence supporting management decisions for hospitalized patients with SAWS, many of whom require critical care, represents both a call to action and an opportunity for the American Thoracic Society and larger scientific communities to improve care for a vulnerable patient population. This report highlights basic, clinical, and implementation research that diverse experts agree will have the greatest impact on improving care for hospitalized patients with SAWS.

Variation in Early Management Practices in Moderate-to-Severe ARDS in the United States: The Severe ARDS: Generating Evidence Study

BACKGROUND

Although specific interventions previously demonstrated benefit in patients with ARDS, use of these interventions is inconsistent, and patient mortality remains high. The impact of variability in center management practices on ARDS mortality rates remains unknown.

RESEARCH QUESTION

What is the impact of treatment variability on mortality in patients with moderate to severe ARDS in the United States?

STUDY DESIGN AND METHODS

We conducted a multicenter, observational cohort study of mechanically ventilated adults with ARDS and Pao2 to Fio2 ratio of ≤ 150 with positive end-expiratory pressure of ≥ 5 cm H2O, who were admitted to 29 US centers between October 1, 2016, and April 30, 2017. The primary outcome was 28-day in-hospital mortality. Center variation in ventilator management, adjunctive therapy use, and mortality also were assessed.

RESULTS

A total of 2,466 patients were enrolled. Median baseline Pao2 to Fio2 ratio was 105 (interquartile range, 78.0-129.0). In-hospital 28-day mortality was 40.7%. Initial adherence to lung protective ventilation (LPV; tidal volume, ≤ 6.5 mL/kg predicted body weight; plateau pressure, or when unavailable, peak inspiratory pressure, ≤ 30 mm H2O) was 31.4% and varied between centers (0%-65%), as did rates of adjunctive therapy use (27.1%-96.4%), methods used (neuromuscular blockade, prone positioning, systemic steroids, pulmonary vasodilators, and extracorporeal support), and mortality (16.7%-73.3%). Center standardized mortality ratios (SMRs), calculated using baseline patient-level characteristics to derive expected mortality rate, ranged from 0.33 to 1.98. Of the treatment-level factors explored, only center adherence to early LPV was correlated with SMR.

INTERPRETATION

Substantial center-to-center variability exists in ARDS management, suggesting that further opportunities for improving ARDS outcomes exist. Early adherence to LPV was associated with lower center mortality and may be a surrogate for overall quality of care processes. Future collaboration is needed to identify additional treatment-level factors influencing center-level outcomes.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT03021824; URL: www.clinicaltrials.gov.

Implementing nudges to promote utilization of low tidal volume ventilation (INPUT): a stepped-wedge, hybrid type III trial of strategies to improve evidence-based mechanical ventilation management

Background

Behavioral economic insights have yielded strategies to overcome implementation barriers. For example, default strategies and accountable justification strategies have improved adherence to best practices in clinical settings. Embedding such strategies in the electronic health record (EHR) holds promise for simple and scalable approaches to facilitating implementation. A proven-effective but under-utilized treatment for patients who undergo mechanical ventilation involves prescribing low tidal volumes, which protects the lungs from injury. We will evaluate EHR-based implementation strategies grounded in behavioral economic theory to improve evidence-based management of mechanical ventilation.

Methods

The Implementing Nudges to Promote Utilization of low Tidal volume ventilation (INPUT) study is a pragmatic, stepped-wedge, hybrid type III effectiveness implementation trial of three strategies to improve adherence to low tidal volume ventilation. The strategies target clinicians who enter electronic orders and respiratory therapists who manage the mechanical ventilator, two key stakeholder groups. INPUT has five study arms: usual care, a default strategy within the mechanical ventilation order, an accountable justification strategy within the mechanical ventilation order, and each of the order strategies combined with an accountable justification strategy within flowsheet documentation. We will create six matched pairs of twelve intensive care units (ICUs) in five hospitals in one large health system to balance patient volume and baseline adherence to low tidal volume ventilation. We will randomly assign ICUs within each matched pair to one of the order panels, and each pair to one of six wedges, which will determine date of adoption of the order panel strategy. All ICUs will adopt the flowsheet documentation strategy 6 months afterwards. The primary outcome will be fidelity to low tidal volume ventilation. The secondary effectiveness outcomes will include in-hospital mortality, duration of mechanical ventilation, ICU and hospital length of stay, and occurrence of potential adverse events.

Discussion

This stepped-wedge, hybrid type III trial will provide evidence regarding the role of EHR-based behavioral economic strategies to improve adherence to evidence-based practices among patients who undergo mechanical ventilation in ICUs, thereby advancing the field of implementation science, as well as testing the effectiveness of low tidal volume ventilation among broad patient populations.

Trial registration

ClinicalTrials.gov, NCT04663802. Registered 11 December 2020.

Adherence to Lung Protective Ventilation in Patients With Coronavirus Disease 2019

OBJECTIVES:

Prior studies have demonstrated suboptimal adherence to lung protective ventilation among patients with acute respiratory distress syndrome. A common barrier to providing this evidence-based practice is diagnostic uncertainty. We sought to test the hypothesis that patients with acute respiratory distress syndrome due to coronavirus disease 2019, in whom acute respiratory distress syndrome is easily recognized, would be more likely to receive low tidal volume ventilation than concurrently admitted acute respiratory distress syndrome patients without coronavirus disease 2019.

DESIGN:

Retrospective cohort study.

SETTING:

Five hospitals of a single health system.

PATIENTS:

Mechanically ventilated patients with coronavirus disease 2019 or noncoronavirus disease 2019 acute respiratory distress syndrome as identified by an automated, electronic acute respiratory distress syndrome finder in clinical use at study hospitals.

INTERVENTIONS:

None.

MEASUREMENTS AND MAIN RESULTS:

Among 333 coronavirus disease 2019 patients and 234 noncoronavirus disease 2019 acute respiratory distress syndrome patients, the average initial tidal volume was 6.4 cc/kg predicted body weight and 6.8 cc/kg predicted body weight, respectively. Patients had tidal volumes less than or equal to 6.5 cc/kg predicted body weight for a mean of 70% of the first 72 hours of mechanical ventilation in the coronavirus disease 2019 cohort, compared with 52% in the noncoronavirus disease 2019 cohort (unadjusted p < 0.001). After adjusting for height, gender, admitting hospital, and whether or not the patient was admitted to a medical specialty ICU, coronavirus disease 2019 diagnosis was associated with a 21% higher percentage of time receiving tidal volumes less than or equal to 6.5 cc/kg predicted body weight within the first 72 hours of mechanical ventilation (95% CI, 14–28%; p < 0.001).

CONCLUSIONS:

Adherence to low tidal volume ventilation during the first 72 hours of mechanical ventilation is higher in patients with coronavirus disease 2019 than with acute respiratory distress syndrome without coronavirus disease 2019. This population may present an opportunity to understand facilitators of implementation of this life-saving evidence-based practice.

The relationship of tidal volume and driving pressure with mortality in hypoxic patients receiving mechanical ventilation

PURPOSE

To determine whether tidal volume/predicted body weight (TV/PBW) or driving pressure (DP) are associated with mortality in a heterogeneous population of hypoxic mechanically ventilated patients.

METHODS

A retrospective cohort study involving 18 intensive care units included consecutive patients ≥18 years old, receiving mechanical ventilation for ≥3 days, with a PaO2/FiO2 ratio ≤300 mmHg, whether or not they met full criteria for ARDS. The main outcome was hospital mortality. Multiple logistic regression (MLR) incorporated TV/PBW, DP, and potential confounders including age, APACHE IVa® predicted hospital mortality, respiratory system compliance (CRS), and PaO2/FiO2. Predetermined strata of TV/PBW were compared using MLR.

RESULTS

Our cohort comprised 5,167 patients with mean age 61.9 years, APACHE IVa® score 79.3, PaO2/FiO2 166 mmHg and CRS 40.5 ml/cm H2O. Regression analysis revealed that patients receiving DP one standard deviation above the mean or higher (≥19 cmH20) had an adjusted odds ratio for mortality (ORmort) = 1.10 (95% CI: 1.06-1.13, p = 0.009). Regression analysis showed a U-shaped relationship between strata of TV/PBW and adjusted mortality. Using TV/PBW 4-6 ml/kg as the referent group, patients receiving >10 ml/kg had similar adjusted ORmort, but those receiving 6-7, 7-8 and 8-10 ml/kg had lower adjusted ORmort (95%CI) of 0.81 (0.65-1.00), 0.78 (0.63-0.97) and 0.80 0.67-1.01) respectively. The adjusted ORmort in patients receiving 4-6 ml/kg was 1.26 (95%CI: 1.04-1.52) compared to patients receiving 6-10 ml/kg.

CONCLUSIONS

Driving pressures ≥19 cmH2O were associated with increased adjusted mortality. TV/PBW 4-6ml/kg were used in less than 15% of patients and associated with increased adjusted mortality compared to TV/PBW 6-10 ml/kg used in 82% of patients. Prospective clinical trials are needed to prove whether limiting DP or the use of TV/PBW 6-10 ml/kg versus 4-6 ml/kg benefits mortality.

Biomarker-Based Classification of Patients With Acute Respiratory Failure Into Inflammatory Subphenotypes: A Single-Center Exploratory Study

OBJECTIVES

Hyper- and hypoinflammatory subphenotypes discovered in patients with acute respiratory distress syndrome predict clinical outcomes and therapeutic responses. These subphenotypes may be important in broader critically ill patient populations with acute respiratory failure regardless of clinical diagnosis. We investigated subphenotyping with latent class analysis in an inclusive population of acute respiratory failure, derived a parsimonious model for subphenotypic predictions based on a small set of variables, and examined associations with clinical outcomes.

DESIGN

Prospective, observational cohort study.

SETTING

Single-center, academic medical ICU.

PATIENTS

Mechanically ventilated patients with acute respiratory failure.

MEASUREMENTS AND MAIN RESULTS

We included 498 patients with acute respiratory failure (acute respiratory distress syndrome: 143, at-risk for acute respiratory distress syndrome: 198, congestive heart failure: 37, acute on chronic respiratory failure: 23, airway protection: 61, and multifactorial: 35) in our derivation cohort and measured 10 baseline plasma biomarkers. Latent class analysis considering clinical variables and biomarkers determined that a two-class model offered optimal fit (23% hyperinflammatory subphenotype). Distribution of hyperinflammatory subphenotype varied among acute respiratory failure etiologies (acute respiratory distress syndrome: 31%, at-risk for acute respiratory distress syndrome: 27%, congestive heart failure: 22%, acute on chronic respiratory failure 0%, airway protection: 5%, and multifactorial: 14%). Hyperinflammatory patients had higher Sequential Organ Failure Assessment scores, fewer ventilator-free days, and higher 30- and 90-day mortality (all p < 0.001). We derived a parsimonious model consisting of angiopoietin-2, soluble tumor necrosis factor receptor-1, procalcitonin, and bicarbonate and classified subphenotypes in a validation cohort (n = 139). Hyperinflammatory patients (19%) demonstrated higher levels of inflammatory biomarkers not included in the model (p < 0.01) and worse outcomes.

CONCLUSIONS

Host-response subphenotypes are observable in a heterogeneous population with acute respiratory failure and predict clinical outcomes. Simple, biomarker-based models can offer prognostic enrichment in patients with acute respiratory failure. The differential distribution of subphenotypes by specific etiologies of acute respiratory failure indicates that subphenotyping may be more relevant in patients with hypoxemic causes of acute respiratory failure and not in patients intubated for airway protection or acute on chronic decompensation.

Impact of Clinician Recognition of Acute Respiratory Distress Syndrome on Evidenced-Based Interventions in the Medical ICU

Acute respiratory distress syndrome is underrecognized in the ICU, but it remains uncertain if acute respiratory distress syndrome recognition affects evidence-based acute respiratory distress syndrome care in the modern era. We sought to determine the rate of clinician-recognized acute respiratory distress syndrome in an academic medical ICU and understand how clinician-recognized-acute respiratory distress syndrome affects clinical care and patient-centered outcomes.

DESIGN

Observational cohort study.

SETTING

Single medical ICU at an academic tertiary-care hospital.

PATIENTS

Nine hundred seventy-seven critically ill adults (381 with expert-adjudicated acute respiratory distress syndrome) enrolled from 2006 to 2015.

INTERVENTIONS

Clinician-recognized-acute respiratory distress syndrome was identified using an electronic keyword search of clinical notes in the electronic health record. We assessed the classification performance of clinician-recognized acute respiratory distress syndrome for identifying expert-adjudicated acute respiratory distress syndrome. We also compared differences in ventilator settings, diuretic prescriptions, and cumulative fluid balance between clinician-recognized acute respiratory distress syndrome and unrecognized acute respiratory distress syndrome.

MEASUREMENTS AND MAIN RESULTS

Overall, clinician-recognized-acute respiratory distress syndrome had a sensitivity of 47.5%, specificity 91.1%, positive predictive value 77.4%, and negative predictive value 73.1% for expert-adjudicated acute respiratory distress syndrome. Among the 381 expert-adjudicated acute respiratory distress syndrome cases, we did not observe any differences in ventilator tidal volumes between clinician-recognized-acute respiratory distress syndrome and unrecognized acute respiratory distress syndrome, but clinician-recognized-acute respiratory distress syndrome patients had a more negative cumulative fluid balance (mean difference, -781 mL; 95% CI, [-1,846 to +283]) and were more likely to receive diuretics (49.3% vs 35.7%, p = 0.02). There were no differences in mortality, ICU length of stay, or ventilator-free days.

CONCLUSIONS

Acute respiratory distress syndrome recognition was low in this single-center study. Although acute respiratory distress syndrome recognition was not associated with lower ventilator volumes, it was associated with differences in behaviors related to fluid management. These findings have implications for the design of future studies promoting evidence-based acute respiratory distress syndrome interventions in the ICU.

Double masking protection vs. comfort-A quantitative assessment

COVID-19 has forced humankind to adopt face masks as an integral part of everyday life. This preventive measure is an effective source control technique to curb the spread of COVID-19 and other similar diseases. The virus responsible for causing COVID-19 has undergone several mutations in the recent past, including B.1.1.7, B.1.351, P.1, and N501Y, B.1.617, with a higher infectious rate. These viruses' variants are mainly responsible for the recent spike in COVID-19 cases and associated steep rise in mortality rate worldwide. Under these circumstances, the Center for Disease Control (CDC) and health experts recommend double masking, which mainly includes a surgical mask and a cotton mask for the general public. This combination provides an additional layer of protection and masks fitment to minimize the leakage of droplets expelled during coughing, sneezing, talking, and breathing. This leakage may cause airborne transmission of the virus. In the present study, we report a systematic quantitative unsteady pressure measurement supplement with flow visualization to quantify the effectiveness of a single and double mask. We have also evaluated double masking consisting of a surgical mask and an N-95 mask used by medical professionals. A simple knot improves the surgical mask fitment significantly, and hence, the leakage of droplets is minimized. The leakage of the droplets was reduced to a large extent by using a double mask combination of a two-layer cotton mask over the surgical mask with a knot. The double mask combination of surgical + N-95 and two-layer cotton + N-95 masks showed the most promising results, and no leakage of the droplets is observed in the forward direction. A double mask combination of surgical and N-95 mask offers 8.6% and 5.6% lower mean and peak pressures compared to surgical, and cotton mask. The best results are observed with cotton and N-95 masks with 54.6% and 23% lower mean and peak pressures than surgical and cotton masks; hence, this combination will offer more comfort to the wearer.

Clinician Recognition of the Acute Respiratory Distress Syndrome: Risk Factors for Under-Recognition and Trends Over Time

OBJECTIVES

The acute respiratory distress syndrome is common in critically ill patients. Recognition is crucial because acute respiratory distress syndrome is associated with a high mortality rate, and low tidal volume ventilation improves mortality. However, acute respiratory distress syndrome often goes unrecognized. Risk factors for under-recognition and trends over time have not been fully described.

DESIGN

Retrospective chart review of patients with acute respiratory distress syndrome from a prospective cohort study of critically ill patients. For each patient's ICU stay, we searched the chart for terms that indicated that acute respiratory distress syndrome was diagnosed, in the differential diagnosis, or treated with low tidal volume ventilation.

SETTING

ICUs at a tertiary hospital at the University of California, San Francisco between 2008 and 2016.

PATIENTS

Critically ill patients with acute respiratory distress syndrome.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Acute respiratory distress syndrome was recognized in 70% of patients, and recognition increased from 60% in 2008-2009 to 92% in 2016 (p = 0.004). Use of tidal volumes less than 6.5 mL/kg also increased (p < 0.001) from 20% to 92%. Increased acute respiratory distress syndrome severity (p = 0.01) and vasopressor use (p = 0.04) were associated with greater recognition. Clinician diagnosis of acute respiratory distress syndrome and inclusion of acute respiratory distress syndrome in the differential diagnosis were associated with tidal volumes less than 6.5 mL/kg (51% use of tidal volume ≤ 6.5 mL/kg if acute respiratory distress syndrome recognized vs 15% if not recognized; p = 0.002). Diagnosing acute respiratory distress syndrome was associated with lower tidal volume in multivariate analysis.

CONCLUSIONS

Although acute respiratory distress syndrome recognition and low tidal volume ventilation use have increased over time, they remain less than universal. Clinician recognition of acute respiratory distress syndrome is associated with both systemic and respiratory severity of illness and is also associated with use of low tidal volume ventilation.

Deep learning to detect acute respiratory distress syndrome on chest radiographs: a retrospective study with external validation

Background

Acute respiratory distress syndrome (ARDS) is a common, but under-recognised, critical illness syndrome associated with high mortality. An important factor in its under-recognition is the variability in chest radiograph interpretation for ARDS. We sought to train a deep convolutional neural network (CNN) to detect ARDS findings on chest radiographs.

Methods

CNNs were pretrained on 595 506 radiographs from two centres to identify common chest findings (eg, opacity and effusion), and then trained on 8072 radiographs annotated for ARDS by multiple physicians using various transfer learning approaches. The best performing CNN was tested on chest radiographs in an internal and external cohort, including a subset reviewed by six physicians, including a chest radiologist and physicians trained in intensive care medicine. Chest radiograph data were acquired from four US hospitals.

Findings

In an internal test set of 1560 chest radiographs from 455 patients with acute hypoxaemic respiratory failure, a CNN could detect ARDS with an area under the receiver operator characteristics curve (AUROC) of 0·92 (95% CI 0·89–0·94). In the subgroup of 413 images reviewed by at least six physicians, its AUROC was 0·93 (95% CI 0·88–0·96), sensitivity 83·0% (95% CI 74·0–91·1), and specificity 88·3% (95% CI 83·1–92·8). Among images with zero of six ARDS annotations (n=155), the median CNN probability was 11%, with six (4%) assigned a probability above 50%. Among images with six of six ARDS annotations (n=27), the median CNN probability was 91%, with two (7%) assigned a probability below 50%. In an external cohort of 958 chest radiographs from 431 patients with sepsis, the AUROC was 0·88 (95% CI 0·85–0·91). When radiographs annotated as equivocal were excluded, the AUROC was 0·93 (0·92–0·95).

Interpretation

A CNN can be trained to achieve expert physician-level performance in ARDS detection on chest radiographs. Further research is needed to evaluate the use of these algorithms to support real-time identification of ARDS patients to ensure fidelity with evidence-based care or to support ongoing ARDS research.

Funding

National Institutes of Health, Department of Defense, and Department of Veterans Affairs.

Implementation of Protocolized Care in ARDS Improves Outcomes

BACKGROUND

Treatments for ARDS that improve patient outcomes include use of lung-protective ventilation, prone ventilation, and conservative fluid management. Implementation of ARDS protocols via educational programs might improve adherence and outcomes. The objective of this study was to investigate the effects of an ARDS protocol implementation on outcomes and adherence with ARDS guidelines.

METHODS

This was a single-center, interventional, comparative study before and after protocol implementation. Staff education for the ARDS protocol was implemented between June 2014 and May 2015. A retrospective cohort analysis was conducted during between January 2012 and May 2014 (pre-protocol) and between June 2015 and June 2017 (post-protocol). A total of 450 subjects with ARDS were included. After propensity score matching, 432 subjects were analyzed. Of those, 330 subjects were treated after protocol implementation.

RESULTS

The median (interquartile range [IQR]) plateau pressure and tidal volume over the first 3 d decreased significantly after protocol implementation (30.5 [IQR 24.2-33] vs 25.5 [IQR 21.7-30], P = .01 and 7.65 vs 7.4 mL/kg predicted body weight, P = .032, respectively). The percentage of subjects with unsafe tidal volume (> 10 mL/kg predicted body weight) decreased (14.4% vs 5.8%, P = .02). The percentage of subjects with safe plateau pressure (≤ 30 cm H₂O) increased (47.4% vs 76.5%, P < .001). PEEP deviation from the ARDSNet PEEP/[Formula: see text] table was significantly lower after the implementation. Mortality at 28 and 90 days improved after implementation (53.9% vs 41.8% and 61.8% vs 48.2%, respectively). Adjusted odds ratios for 28-d and 90-d mortality were 0.47 (95% CI 0.28-0.78) and 0.45 (95% CI 0.27-0.76), respectively.

CONCLUSIONS

ARDS protocol implementation was associated with improved survival and rate of adherence.

Improving Prone Positioning for Severe Acute Respiratory Distress Syndrome during the COVID-19 Pandemic. An Implementation-Mapping Approach

Rationale: Prone positioning reduces mortality in patients with severe acute respiratory distress syndrome (ARDS), a feature of severe coronavirus disease 2019 (COVID-19). Despite this, most patients with ARDS do not receive this lifesaving therapy.Objectives: To identify determinants of prone-positioning use, to develop specific implementation strategies, and to incorporate strategies into an overarching response to the COVID-19 crisis.Methods: We used an implementation-mapping approach guided by implementation-science frameworks. We conducted semistructured interviews with 30 intensive care unit (ICU) clinicians who staffed 12 ICUs within the Penn Medicine Health System and the University of Michigan Medical Center. We performed thematic analysis using the Consolidated Framework for Implementation Research. We then conducted three focus groups with a task force of ICU leaders to develop an implementation menu, using the Expert Recommendations for Implementing Change framework. The implementation strategies were adapted as part of the Penn Medicine COVID-19 pandemic response.Results: We identified five broad themes of determinants of prone positioning, including knowledge, resources, alternative therapies, team culture, and patient factors, which collectively spanned all five Consolidated Framework for Implementation Research domains. The task force developed five specific implementation strategies, including educational outreach, learning collaborative, clinical protocol, prone-positioning team, and automated alerting, elements of which were rapidly implemented at Penn Medicine.Conclusions: We identified five broad themes of determinants of evidence-based use of prone positioning for severe ARDS and several specific strategies to address these themes. These strategies may be feasible for rapid implementation to increase use of prone positioning for severe ARDS with COVID-19.

Use of Machine Learning to Screen for Acute Respiratory Distress Syndrome Using Raw Ventilator Waveform Data

To develop and characterize a machine learning algorithm to discriminate acute respiratory distress syndrome from other causes of respiratory failure using only ventilator waveform data.

Design

Retrospective, observational cohort study.

Setting

Academic medical center ICU.

Patients

Adults admitted to the ICU requiring invasive mechanical ventilation, including 50 patients with acute respiratory distress syndrome and 50 patients with primary indications for mechanical ventilation other than hypoxemic respiratory failure.

Interventions

None.

Measurements and Main Results

Pressure and flow time series data from mechanical ventilation during the first 24-hours after meeting acute respiratory distress syndrome criteria (or first 24-hr of mechanical ventilation for non-acute respiratory distress syndrome patients) were processed to extract nine physiologic features. A random forest machine learning algorithm was trained to discriminate between the patients with and without acute respiratory distress syndrome. Model performance was assessed using the area under the receiver operating characteristic curve, sensitivity, specificity, positive predictive value, and negative predictive value. Analyses examined performance when the model was trained using data from the first 24 hours and tested using withheld data from either the first 24 hours (24/24 model) or 6 hours (24/6 model). Area under the receiver operating characteristic curve, sensitivity, specificity, positive predictive value, and negative predictive value were 0.88, 0.90, 0.71, 0.77, and 0.90 (24/24); and 0.89, 0.90, 0.75, 0.83, and 0.83 (24/6).

Conclusions

Use of machine learning and physiologic information derived from raw ventilator waveform data may enable acute respiratory distress syndrome screening at early time points after intubation. This approach, combined with traditional diagnostic criteria, could improve timely acute respiratory distress syndrome recognition and enable automated clinical decision support, especially in settings with limited availability of conventional diagnostic tests and electronic health records.

Lung-Protective Ventilation Over 6 Years at a Large Academic Medical Center: An Evaluation of Trends, Adherence, and Perceptions of Benefit

The main objective of this study was to evaluate trends in set tidal volumes across all adult ICUs at a large academic medical center over 6 years, with a focus on adherence to lung-protective ventilation (≤ 8-cc/kg ideal body weight). A secondary objective was to survey providers on their perceptions of lung-protective ventilation and barriers to its implementation.

DESIGN

Retrospective observational analysis (primary objective) and cross-sectional survey study (secondary objective), both at a single center.

PARTICIPANTS

Mechanically ventilated adult patients with a set tidal volume (primary objective) and providers rotating through the Medical and Neurosciences ICUs (secondary objective).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

From 2013 to 2018, the average initial set tidal volume (cc/kg ideal body weight) decreased from 8.99 ± 2.19 to 7.45±1.34 (p < 0.001). The cardiothoracic ICU had the largest change in tidal volume from 11.09 ± 1.96 in 2013 to 7.97 ± 1.03 in 2018 (p < 0.001). Although the majority of tidal volumes across all ICUs were between 6.58 and 8.01 (interquartile range) in 2018, 27% of patients were still being ventilated at volumes greater than 8-cc/kg ideal body weight. Most surveyed respondents felt there was benefit to lung-protective ventilation, though many did not routinely calculate the set tidal volume in cc/kg ideal body weight, and most did not feel it was easily calculable with the current electronic medical record system.

CONCLUSIONS

Despite a trend toward lower tidal volumes over the years, in 2018, over a quarter of mechanically ventilated adult patients were being ventilated with tidal volumes greater than 8 cc/kg. Survey data indicate that despite respondents acknowledging the benefits of lung-protective ventilation, there are barriers to its optimal implementation. Future modifications of the electronic medical record, including a calculator to set tidal volume in cc/kg and the use of default set tidal volumes, may help facilitate the delivery of and adherence to lung-protective ventilation.

Clinicians' Perceptions of Behavioral Economic Strategies to Increase the Use of Lung-Protective Ventilation

Rationale: Lung-protective ventilation (LPV) improves outcomes in patients with acute respiratory distress syndrome (ARDS) and has also shown benefits in patients without ARDS. Despite this evidence, LPV use remains low.Objectives: To understand clinicians' perceptions of using behavioral economic strategies to improve rates of LPV use.Methods: We conducted semistructured interviews of clinicians across seven intensive care units within a university health system. We purposefully sampled clinicians of different professional backgrounds and experience levels. Each interview included descriptions of three of five strategies grounded in behavioral economic theory designed to facilitate clinicians' use of LPV: 1) an order set autopopulated with LPV settings ("default"), 2) an order set providing a choice between autopopulated LPV settings and open-ended order entry for alternative settings ("active choice"), 3) requirement of written justification if settings other than LPV were ordered or documented ("accountable justification"), 4) automated ARDS identification and clinician prompting ("alert"), and 5) provision of clinicians' and their peers' individual rates of LPV use ("peer comparison"). Descriptions were followed by open-ended questions to elicit perceptions about advantages, disadvantages, and acceptability. Initial interview transcripts were reviewed by two investigators to develop a thematic codebook, which was refined iteratively with the use of constant comparative methods.Results: We completed 17 interviews of physicians, nurse practitioners, and respiratory therapists. Strategies that prepopulated settings (default, active choice, and accountable justification) were perceived as providing benefit by reducing workloads and serving as cognitive prompts. The default and active choice strategies were more acceptable than accountable justification, which was perceived as potentially frustrating due to workflow impedance. The alert strategy was met with concerns about alert accuracy and alarm fatigue. The peer comparison strategy led to concerns about timing and fear of punitive measures. Participants believed that the default and active choice strategies would be highly acceptable, whereas few interviewees thought the alert would be acceptable. The active choice strategy was most consistently identified as potentially highly effective.Conclusions: Behavioral economic strategies have great potential as acceptable and potentially effective strategies to increase the use of LPV.

Performance Measure Development, Use, and Measurement of Effectiveness Using the Guideline on Mechanical Ventilation in Acute Respiratory Distress Syndrome. An Official American Thoracic Society Workshop Report

Guideline implementation tools are designed to improve uptake of guideline recommendations in clinical settings but do not uniformly accompany the clinical practice guideline documents. Performance measures are a type of guideline implementation tool with the potential to catalyze behavior change and greater adherence to clinical practice guidelines. However, many performance measures suffer from serious flaws in their design and application, prompting the American Thoracic Society (ATS) to define its own performance measure development standards in a previous workshop in 2012. This report summarizes the proceedings of a follow-up workshop convened to advance the ATS’s work in performance measure development and guideline implementation. To illustrate the application of the ATS’s performance measure development framework, we used the example of a low–tidal volume ventilation performance measure created de novo from the 2017 ATS/European Society of Intensive Care Medicine/Society of Critical Care Medicine mechanical ventilation in acute respiratory distress syndrome clinical practice guideline. We include a detailed explanation of the rationale for the specifications chosen, identification of areas in need of further validity testing, and a preliminary strategy for pilot testing of the performance measure. Pending additional resources and broader performance measure expertise, issuing “preliminary performance measures” and their specifications alongside an ATS clinical practice guideline offers a first step to further the ATS’s guideline implementation agenda. We recommend selectively proceeding with full performance measure development for those measures with positive early user feedback and the greatest potential impact in accordance with ATS leadership guidance.

Implementation of an Academic-to-Community Hospital Intensive Care Unit Quality Improvement Program. Qualitative Analysis of Multilevel Facilitators and Barriers

Rationale: Implementation of evidence-based best practices is influenced by a variety of contextual factors. It is vital to characterize such factors to maintain high-quality care. Patients in the intensive care unit (ICU) are critically ill and require complex, interdisciplinary, evidence-based care to enable high-quality outcomes. Objectives: To identify facilitators and barriers to implementation of an academic-to-community hospital ICU interprofessional quality improvement program, "ICU Innovations." Methods: ICU Innovations is a multimodal quality improvement program implemented between 2014 and 2017 in six community ICUs in rural settings serving underserved patients in South Carolina. ICU Innovations includes quarterly on-site seminars and extensive behind the scenes facilitation to catalyze the implementation of evidence-based best practices. We use qualitative analysis to identify contextual factors related to program implementation processes. Guided by an implementation science framework, the Exploration, Adoption/Preparation, Implementation, Sustainment framework, we conducted semistructured key informant interviews with clinician champions at six community ICUs and six parallel interviews with ICU Innovations' leadership. We developed a qualitative coding template based on the framework and identified contextual factors associated with implementation. Standard data on hospital and ICU structure and processes of care were also collected. Results: Outer and inner factors interconnected dynamically to influence implementation of ICU Innovations. Collaborative engagement between the program developers and partner sites (outer context factor) and site program champion leadership and staff readiness for change (inner context factors) were key influences of implementation. Conclusions: This research focused on rural hospital ICUs with limited or nonexistent intensivist leadership. Although enthusiasm for the ICU Innovations program was initially high, implementation was challenging because of multiple contextual factors. Critical steps for implementation of evidence-based practice in rural hospitals include optimizing engagement with external collaborators, maximizing the role of a committed site champion, and conducting thorough site assessments to ensure staff and organizational readiness for change. Identifying barriers and facilitators to program implementation is an on-going process to tailor and improve program initiatives.

A Comparison of Three Methods of Height Estimation and Their Impact on Low Tidal Volume Ventilation in a Mixed Ethnicity Intensive Care Unit: A Real-World Experience

Background

Height measurement is crucial for calculating predicted body weight (PBW) and establishing low tidal volume ventilation (LTVV). However, standing height is usually unavailable in critically ill patients and supine height may be difficult to obtain.

Objective

We investigated whether there were any significant differences in tidal volumes (VT) obtained using PBW derived from supine, forearm, and lower leg lengths in an intensive care unit (ICU) setting.

Methods

Supine, forearm and lower leg lengths were measured in 100 mechanically ventilated patients. Limb lengths were converted to height and PBW calculated using published formulae. The 6 mL/kg VT for the supine (sVT), forearm (fVT), and lower leg (lVT) methods were compared to each other and to visually estimated VT (estVT).

Results

Forearm length produced the greatest height estimate, leading to a significantly greater tidal volume fVT (437.6 ± 62.1 mL) compared with sVT (385.5 ± 63.8 mL) and lVT (369.1 ± 66.4 mL), (p < .001). There was no significant difference between lVT and sVT, (p = .169). On Bland Altman analysis, the lowest bias was found between lVT and sVT (−16.4 ± 36.0 mL, 95% limits of agreement (LOA) [−86.9, 54.1]), whereas fVT had a bias of 52.1 ± 41.5 mL, 95% LOA [−29.1, 133.4] compared to sVT. The fVT was significantly greater than sVT and lVT in all sexes and ethnic groups (p < .05).

Conclusion

Lower leg length may be a suitable alternative to supine height to facilitate the application of LTVV in an ICU setting.

Pulmonary hypertension with adult respiratory distress syndrome: prevalence, clinical impact, and association with central venous pressure

Pulmonary hypertension (PH) occurs in patients with acute respiratory distress syndrome (ARDS); the most severe form comprises acute cor pulmonale (ACP). Here, we investigated the prevalence of PH in patients with ARDS to evaluate its correlation with ACP risk, ARDS severity and central venous pressure (CVP). We conducted a secondary analysis using data from the MIMIC-III open-source clinical database. The prevalence of PH associated with new-onset ARDS during the first 72 h after intensive care unit admission was investigated; moreover, the association between ACP risk score and PH was validated. We also evaluated the association between elevated CVP (mean CVP > 10 mmHg) and PH and other clinical outcomes. Among 2434 patients who met the ARDS Berlin criteria and underwent echocardiography or pulmonary artery catheterization evaluation, a total of 583 (24.0%) patients were diagnosed with moderate or severe PH, of which 418 had low and 165 had high ACP risk. After adjustment for disease/ARDS severity, ACP risk score, and other demographic variables, elevated CVP was independently associated with the occurrence of PH (odds ratio, 2.239 (1.674, 2.993), p < 0.005). Among patients with PH, higher mean CVP was associated with prolonged hospital stay (13.4 vs. 15.2 days, p = 0.041) and duration of ventilation (116.5 vs. 150.5 h, p = 0.023). Incidence of PH was 24.0% in patients with new-onset ARDS in this retrospective study. Elevated CVP is relevant with higher incidence of PH and worse clinical outcome; these highlighted the importance of hemodynamic monitoring in the management of ARDS.

MADVent: A low-cost ventilator for patients with COVID-19

The COVID‐19 pandemic has produced critical shortages of ventilators worldwide. There is an unmet need for rapidly deployable, emergency‐use ventilators with sufficient functionality to manage COVID‐19 patients with severe acute respiratory distress syndrome. Here, we show the development and validation of a simple, portable and low‐cost ventilator that may be rapidly manufactured with minimal susceptibility to supply chain disruptions. This single‐mode continuous, mandatory, closed‐loop, pressure‐controlled, time‐terminated emergency ventilator offers robust safety and functionality absent in existing solutions to the ventilator shortage. Validated using certified test lungs over a wide range of compliances, pressures, volumes and resistances to meet U.S. Food and Drug Administration standards of safety and efficacy, an Emergency Use Authorization is in review for this system. This emergency ventilator could eliminate controversial ventilator rationing or splitting to serve multiple patients. All design and validation information is provided to facilitate ventilator production even in resource‐limited settings.

Dynamics of acute respiratory distress syndrome development due to smoke inhalation injury: Implications for prolonged field care

BACKGROUND

Smoke inhalation injury (SII) causes 30% to 40% mortality and will increase as a cause of death during prolonged field care. We used a combat relevant model of acute respiratory distress syndrome due to SII to study temporal changes in ventilation-perfusion (V/Q) matching, computed tomography (CT) scan data, and histopathology and hypothesized that SII leads to increase in shunt (Qshunt), V/Q mismatch, lung consolidation, and diffuse alveolar damage.

METHODS

Swine received severe SII and airway pressure release ventilation (APRV, n = 6), or conventional ARDSNet mechanical ventilation (MV) (CMV, n = 8). A control group without injury received volume controlled MV (CTRL, n = 6), The multiple inert gas elimination technique and CT were performed at baseline (BL), 0.5 hours, 1 hours, 2 hours, 24 hours, and 48 hours after injury. Diffuse alveolar damage scoring was performed post mortem. Significance at p less than 0.05: APRV versus CTRL; CMV versus CTRL; APRV versus CMV*; denotes changes versus BL.

RESULTS

(1) SII caused increases in Qshunt more so in APRV than CMV group. Qshunt did not change in CTRL. (2) PaO2-to-FIO2 ratio (PFR) was lower in APRV versus CTRL at 2 hours (375 ± 62‡ vs. 549 ± 40) and 24 hours (126 ± 34‡* vs. 445 ± 5) and 48 hours (120 ± 41‡& vs. 430 ± 13). In CMV animals, PFR was lower versus CTRL and BL at 24 hours (238 ± 33) and 48 hours (98 ± 27). Qshunt correlated with PFR (r = 0.75, p < 0.0001, APRV and (r = 0.65, p < 0.0001, CMV). CT showed decrease in normally aerated lung, while poorly and nonaerated lung increased.

CONCLUSION

Smoke inhalation injury leads to early development of shunt, V/Q mismatch, lung consolidation, and diffuse alveolar damage. These data substantiate the need for new point of injury interventions in the prolonged field care setting.

LEVEL OF EVIDENCE

Animal research.

Association Between Peripheral Blood Oxygen Saturation (SpO2)/Fraction of Inspired Oxygen (FiO2) Ratio Time at Risk and Hospital Mortality in Mechanically Ventilated Patients

INTRODUCTION

Acute respiratory failure requiring mechanical ventilation is a leading cause of mortality in the intensive care unit. Although single peripheral blood oxygen saturation/fraction of inspired oxygen (SpO2/FiO2) ratios of hypoxemia have been evaluated to risk-stratify patients with acute respiratory distress syndrome, the utility of longitudinal SpO2/FiO2 ratios is unknown.

OBJECTIVE

To assess time-based SpO2/FiO2 ratios ≤ 150-SpO2/FiO2 time at risk (SF-TAR)-for predicting mortality in mechanically ventilated patients.

METHODS

Retrospective, observational cohort study of mechanically ventilated patients at 21 community and 2 academic hospitals. Association between the SF-TAR in the first 24 hours of ventilation and mortality was examined using multivariable logistic regression and compared with the worst recorded isolated partial pressure of arterial oxygen/fraction of inspired oxygen (P/F) ratio.

RESULTS

In 28,758 derivation cohort admissions, every 10% increase in SF-TAR was associated with a 24% increase in adjusted odds of hospital mortality (adjusted odds ratio = 1.24; 95% confidence interval [CI] = 1.23-1.26); a similar association was observed in validation cohorts. Discrimination for mortality modestly improved with SF-TAR (area under the receiver operating characteristic curve [AUROC] = 0.81; 95% CI = 0.81-0.82) vs the worst P/F ratio (AUROC = 0.78; 95% CI = 0.78-0.79) and worst SpO2/FiO2 ratio (AUROC = 0.79; 95% CI = 0.79-0.80). The SF-TAR in the first 6 hours offered comparable discrimination for hospital mortality (AUROC = 0.80; 95% CI = 0.79-0.80) to the 24-hour SF-TAR.

CONCLUSION

The SF-TAR can identify ventilated patients at increased risk of death, offering modest improvements compared with single SpO2/FiO2 and P/F ratios. This longitudinal, noninvasive, and broadly generalizable tool may have particular utility for early phenotyping and risk stratification using electronic health record data in ventilated patients.

Evaluating Delivery of Low Tidal Volume Ventilation in Six ICUs Using Electronic Health Record Data

OBJECTIVES

Mechanical ventilation with low tidal volumes is recommended for all patients with acute respiratory distress syndrome and may be beneficial to other intubated patients, yet consistent implementation remains difficult to obtain. Using detailed electronic health record data, we examined patterns of tidal volume administration, the effect on clinical outcomes, and alternate metrics for evaluating low tidal volume compliance in clinical practice.

DESIGN

Observational cohort study.

SETTING

Six ICUs in a single hospital system.

PATIENTS

Adult patients who received invasive mechanical ventilation more than 12 hours.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Tidal volumes were analyzed across 1,905 hospitalizations. Although mean tidal volume was 6.8 mL/kg predicted body weight, 40% of patients were exposed to tidal volumes greater than 8 mL/kg predicted body weight, with 11% for more than 24 hours. At a patient level, exposure to 24 total hours of tidal volumes greater than 8 mL/kg predicted body weight was associated with increased mortality (odds ratio, 1.82; 95% CI, 1.20-2.78), whereas mean tidal volume exposure was not (odds ratio, 0.87/1 mL/kg increase; 95% CI, 0.74-1.02). Initial tidal volume settings strongly predicted exposure to volumes greater than 8 mL/kg for 24 hours; the adjusted rate was 21.5% when initial volumes were greater than 8 mL/kg predicted body weight and 7.1% when initial volumes were less than 8 mL/kg predicted body weight. Across ICUs, correlation of mean tidal volume with alternative measures of low tidal volume delivery ranged from 0.38 to 0.66.

CONCLUSIONS

Despite low mean tidal volume in the cohort, a significant percentage of patients were exposed to a prolonged duration of high tidal volumes which was correlated with higher mortality. Detailed ventilator records in the electronic health record provide a unique window for evaluating low tidal volume delivery and targets for improvement.

A quantitative approach for the analysis of clinician recognition of acute respiratory distress syndrome using electronic health record data

IMPORTANCE

Despite its efficacy, low tidal volume ventilation (LTVV) remains severely underutilized for patients with acute respiratory distress syndrome (ARDS). Physician under-recognition of ARDS is a significant barrier to LTVV use. We propose a computational method that addresses some of the limitations of the current approaches to automated measurement of whether ARDS is recognized by physicians.

OBJECTIVE

To quantify patient and physician factors affecting physicians' tidal volume selection and to build a computational model of physician recognition of ARDS that accounts for these factors.

DESIGN, SETTING, AND PARTICIPANTS

In this cross-sectional study, electronic health record data were collected for 361 ARDS patients and 388 non-ARDS hypoxemic (control) patients in nine adult intensive care units at four hospitals between June 24 and December 31, 2013.

METHODS

Standardized tidal volumes (mL/kg predicted body weight) were chosen as a proxy for physician decision-making behavior. Using data-science approaches, we quantified the effect of eight factors (six severity of illness, two physician behaviors) on selected standardized tidal volumes in ARDS and control patients. Significant factors were incorporated in computational behavioral models of physician recognition of ARDS.

RESULTS

Hypoxemia severity and ARDS documentation in physicians' notes were associated with lower standardized tidal volumes in the ARDS cohort. Greater patient height was associated with lower standardized tidal volumes (which is already normalized for height) in both ARDS and control patients. The recognition model yielded a mean (99% confidence interval) physician recognition of ARDS of 22% (9%-42%) for mild, 34% (19%-49%) for moderate, and 67% (41%-100%) for severe ARDS.

CONCLUSIONS AND RELEVANCE

In this study, patient characteristics and physician behaviors were demonstrated to be associated with differences in ventilator management in both ARDS and control patients. Our model of physician ARDS recognition measurement accounts for these clinical variables, providing an electronic approach that moves beyond relying on chart documentation or resource intensive approaches.

Reporting of Sepsis Cases for Performance Measurement Versus for Reimbursement in New York State

OBJECTIVES

Under "Rory's Regulations," New York State Article 28 acute care hospitals were mandated to implement sepsis protocols and report patient-level data. This study sought to determine how well cases reported under state mandate align with discharge records in a statewide administrative database.

DESIGN

Observational cohort study.

SETTING

First 27 months of mandated sepsis reporting (April 1, 2014, to June 30, 2016).

PATIENTS

Hospitalizations with sepsis at New York State Article 28 acute care hospitals.

INTERVENTION

Sepsis regulations with mandated reporting.

MEASUREMENTS AND MAIN RESULTS

We compared cases reported to the New York State Department of Health Sepsis Clinical Database with discharge records in the Statewide Planning and Research Cooperative System database. We classified discharges as 1) "coded sepsis discharges"-a diagnosis code for severe sepsis or septic shock and 2) "possible sepsis discharges," using Dombrovskiy and Angus criteria. Of 111,816 sepsis cases reported to the New York State Department of Health Sepsis Clinical Database, 105,722 (94.5%) were matched to discharge records in Statewide Planning and Research Cooperative System. The percentage of coded sepsis discharges reported increased from 67.5% in the first quarter to 81.3% in the final quarter of the study period (mean, 77.7%). Accounting for unmatched cases, as many as 82.7% of coded sepsis discharges were potentially reported, whereas at least 17.3% were unreported. Compared with unreported discharges, reported discharges had higher rates of acute organ dysfunction (e.g., cardiovascular dysfunction 63.0% vs 51.8%; p < 0.001) and higher in-hospital mortality (30.2% vs 26.1%; p < 0.001). Hospital characteristics (e.g., number of beds, teaching status, volume of sepsis cases) were similar between hospitals with a higher versus lower percent of discharges reported, p values greater than 0.05 for all. Hospitals' percent of discharges reported was not correlated with risk-adjusted mortality of their submitted cases (Pearson correlation coefficient 0.11; p = 0.17).

CONCLUSIONS

Approximately four of five discharges with a diagnosis code of severe sepsis or septic shock in the Statewide Planning and Research Cooperative System data were reported in the New York State Department of Health Sepsis Clinical Database. Incomplete reporting appears to be driven more by underrecognition than attempts to game the system, with minimal bias to risk-adjusted hospital performance measurement.