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

Adherence to Lung Protective Ventilation in ARDS: A Mixed Methods Study Using Real-Time Continuously Monitored Ventilation Data

Background: Lung-protective ventilation is a standard intervention for mitigating ventilator-induced lung injury in patients with ARDS. Despite its efficacy, adherence to contemporary evidence-based guidelines remains suboptimal. We aimed to identify factors that affect the adherence of staff to applying lung-protective ventilation guidelines by analyzing real-time, continuously monitored ventilation data over a 5-year longitudinal period. Methods: We conducted retrospective cohort and qualitative studies. Subjects with billing code J80 who survived at least 48 h of continuous mandatory ventilation with volume control in critical care settings between January 1, 2018, and December 31, 2022, were eligible. Tidal volume was measured dynamically (1-min resolution) and averaged hourly. The lung-protective ventilation setting studied was ≤6 mL/kg predicted body weight. A subgroup analysis was conducted by considering COVID-19 status. Focus groups of critical-care providers were convened to investigate the possible reasons for the non-utilization of lung-protective ventilation. Results: Among 1,055 subjects, 42.4% were on lung-protective ventilation settings at 48 h. Male sex was correlated with lung-protective ventilation (odds ratio [OR] 1.63, 95% CI 1.08-2.47), whereas age ≥60 y was associated with no lung-protective ventilation use (OR 0.61, 95% CI 0.39-0.94] in the subjects with non-COVID-19 etiologies. Improved staff adherence was observed in the subjects with COVID-19 early in the pandemic when COVID-19 (OR 1.48, 95% CI 1.07-2.04), male sex (OR 2.42, 95% CI 1.79-3.29), and neuromuscular blocking agent use within 48 h (OR 1.69, 95% CI 1.25-2.29) were correlated with staff placing subjects on lung-protective ventilation. However, lung-protective ventilation use occurred less frequently by staff managing subjects with cancer (OR 0.59, 95% CI 0.35-0.99) and hypertension (OR 0.62, 95% CI 0.45-0.85). Focus groups supported these findings and highlighted the need for an accurate height measurement on unit admission to determine the appropriate target tidal volume. Conclusions: Staff are not yet universally adherent to lung-protective ventilation best practices. Strategies, for example, continuous monitoring, with frequent feedback to clinical teams may help.

Respiratory Therapist-Driven Mechanical Ventilation Protocol Is Associated With Increased Lung Protective Ventilation

BACKGROUND

Mechanical ventilation is a common life-saving procedure but can lead to serious complications, including ARDS and oxygen toxicity. Nonadherence to lung-protective ventilation guidelines is common. We hypothesized that a respiratory therapist-driven mechanical ventilation bundle could increase adherence to lung-protective ventilation and decrease the incidence of pulmonary complications in the ICU.

METHODS

A respiratory therapist-driven protocol was implemented on August 1, 2018, in all adult ICUs of a Midwestern academic tertiary center. The protocol targeted low tidal volume, adequate PEEP, limiting oxygen, adequate breathing frequency, and head of the bed elevation. Adherence to lung-protective guidelines and clinical outcomes were retrospectively observed in adult subjects admitted to the ICU and on ventilation for ≥ 24 h between January 2011 and December 2019.

RESULTS

We included 666 subjects; 68.5% were in the pre-intervention group and 31.5% were in the post-intervention group. After adjusting for body mass index and intubation indication, a significant increase in overall adherence to lung-protective ventilation guidelines was observed in the post-intervention period (adjusted odds ratio 2.48, 95% CI 1.73-3.56). Fewer subjects were diagnosed with ARDS in the post-intervention group (adjusted odds ratio 0.22, 95% CI 0.08-0.65) than in the pre-intervention group. There was no difference in the incidence of ventilator-associated pneumonia, ventilator-free days, ICU mortality, or death within 1 month of ICU discharge.

CONCLUSIONS

A respiratory therapist-driven protocol increased adherence to lung-protective mechanical ventilation guidelines in the ICU and was associated with decreased ARDS incidence.

Assessing Evidence-Based Practice Knowledge, Self-Efficacy, and Use Among Respiratory Therapists

BACKGROUND

Evidence-based practice is at the forefront of providing quality patient care by using the best available evidence and clinical expertise, while also considering patient needs and preferences for clinical decisions. However, evidence-based practice may not be consistently used even when the evidence supports the therapy. The purpose of this study was to assess the factors associated with the use of evidence-based practice among respiratory therapy faculty teaching in a large community college system and post-professional students enrolled in a university-based, respiratory therapy baccalaureate degree-advancement program.

METHODS

A non-probability, descriptive survey research design was used to develop and administer an online questionnaire.

RESULTS

All respondents demonstrated sufficient knowledge and understanding of introductory concepts of evidence-based practice but knowledge of specific components of the evidence-based practice process was not as strong. Self-efficacy in knowledge and the use of evidence-based practice among faculty and degree-advancement students varied. Faculty and students rated their self-efficacy high in assessing patients' needs, values, and treatment preferences but ratings were lower for using the PICO (patient/population/problem, intervention, comparison, outcome) technique and interpreting common statistical tests. Students viewed their previous evidence-based practice learning experiences more favorably compared with faculty (P = .008). Faculty and students searched and read the research literature more often compared with critically appraising and using the research literature. Logistic regression analysis indicated no statistically significant relationship of knowledge, self-efficacy, and learning experiences to the use of evidence-based practice among respiratory therapy students, Χ 2 (4, N = 54) = 7.73; P = .10.

CONCLUSIONS

Analysis of the results suggested that respiratory therapy faculty and students were knowledgeable and confident with regard to evidence-based practice but their use of evidence-based practice in clinical decisions was limited. Although the evidence-based practice knowledge, self-efficacy, and learning experiences had minimal influence on the use of evidence-based practice, the results of the study provide a foundation for future research.

Adherence to lung protective mechanical ventilation in patients admitted to a surgical intensive care unit and the associated increased mortality

Background

The adherence rate to the lung protective ventilation (LPV) strategy, which is generally accepted as a standard practice in mechanically ventilated patients, reported in the literature is approximately 40%. This study aimed to determine the adherence rate to the LPV strategy, factors associated with this adherence, and related clinical outcomes in mechanically ventilated patients admitted to the surgical intensive care unit (SICU).

Methods

This prospective observational study was conducted in the SICU of a tertiary university-based hospital between April 2018 and February 2019. Three hundred and six adult patients admitted to the SICU who required mechanical ventilation support for more than 12 h were included. Ventilator parameters at the initiation of mechanical ventilation support in the SICU were recorded. The LPV strategy was defined as ventilation with a tidal volume of equal or less than 8 ml/kg of predicted body weight plus positive end-expiratory pressure of at least 5 cm H2O. Demographic and clinical data were recorded and analyzed.

Results

There were 306 patients included in this study. The adherence rate to the LPV strategy was 36.9%. Height was the only factor associated with adherence to the LPV strategy (odds ratio for each cm, 1.10; 95% confidence interval (CI), 1.06-1.15). Cox regression analysis showed that the LPV strategy was associated with increased 90-day mortality (hazard ratio, 1.73; 95% CI, 1.02-2.94).

Conclusion

The adherence rate to the LPV strategy among patients admitted to the SICU was modest. Further studies are warranted to explore whether the application of the LPV strategy is simply a marker of disease severity or a causative factor for increased mortality.

Forecasting disease trajectories in critical illness: comparison of probabilistic dynamic systems to static models to predict patient status in the intensive care unit

OBJECTIVE

Conventional prediction models fail to integrate the constantly evolving nature of critical illness. Alternative modelling approaches to study dynamic changes in critical illness progression are needed. We compare static risk prediction models to dynamic probabilistic models in early critical illness.

DESIGN

We developed models to simulate disease trajectories of critically ill COVID-19 patients across different disease states. Eighty per cent of cases were randomly assigned to a training and 20% of the cases were used as a validation cohort. Conventional risk prediction models were developed to analyse different disease states for critically ill patients for the first 7 days of intensive care unit (ICU) stay. Daily disease state transitions were modelled using a series of multivariable, multinomial logistic regression models. A probabilistic dynamic systems modelling approach was used to predict disease trajectory over the first 7 days of an ICU admission. Forecast accuracy was assessed and simulated patient clinical trajectories were developed through our algorithm.

SETTING AND PARTICIPANTS

We retrospectively studied patients admitted to a Cleveland Clinic Healthcare System in Ohio, for the treatment of COVID-19 from March 2020 to December 2022.

RESULTS

5241 patients were included in the analysis. For ICU days 2-7, the static (conventional) modelling approach, the accuracy of the models steadily decreased as a function of time, with area under the curve (AUC) for each health state below 0.8. But the dynamic forecasting approach improved its ability to predict as a function of time. AUC for the dynamic forecasting approach were all above 0.90 for ICU days 4-7 for all states.

CONCLUSION

We demonstrated that modelling critical care outcomes as a dynamic system improved the forecasting accuracy of the disease state. Our model accurately identified different disease conditions and trajectories, with a <10% misclassification rate over the first week of critical illness.

Low Tidal Volume Ventilation Is Poorly Implemented for Patients in North American and United Kingdom ICUs Using Electronic Health Records

BACKGROUND

Low tidal volume ventilation (LTVV; < 8 mL/kg predicted body weight [PBW]) is a well-established standard of care associated with improved outcomes. This study used data collated in multicenter electronic health record ICU databases from the United Kingdom and the United States to analyze the use of LTVV in routine clinical practice.

RESEARCH QUESTION

What factors are associated with adherence to LTVV in the United Kingdom and North America?

STUDY DESIGN

This was a retrospective, multicenter study across the United Kingdom and United States of patients who were mechanically ventilated.

METHODS

Factors associated with adherence to LTVV were assessed in all patients in both databases who were mechanically ventilated for > 48 h. We observed trends over time and investigated whether LTVV was associated with patient outcomes (30-day mortality and duration of ventilation) and identified strategies to improve adherence to LTVV.

RESULTS

A total of 5,466 (Critical Care Health Informatics Collaborative [CCHIC]) and 7,384 electronic ICU collaborative research database [eICU-CRD] patients were ventilated for > 48 h and had data of suitable quality for analysis. The median tidal volume (VT) values were 7.48 mL/kg PBW (CCHIC) and 7.91 mL/kg PBW (eICU-CRD). The patients at highest risk of not receiving LTVV were shorter than 160 cm (CCHIC) and 165 cm (eICU-CRD). Those with BMI > 30 kg/m2 (CCHIC OR, 1.9 [95% CI, 1.7-2.13]; eICU-CRD OR, 1.61 [95% CI, 1.49-1.75]) and female patients (CCHIC OR, 2.39 [95% CI, 2.16-2.65]; eICU-CRD OR, 2.29 [95% CI, 2.26-2.31]) were at increased risk of having median VT > 8 mL/kg PBW. Patients with median VT < 8 mL/kg PBW had decreased 30-day mortality in the CCHIC database (CCHIC cause-specific hazard ratio, 0.86 [95% CI, 0.76-0.97]; eICU-CRD cause-specific hazard ratio, 0.9 [95% CI, 0.86-1.00]). There was a significant reduction in VT over time in the CCHIC database.

INTERPRETATION

There has been limited implementation of LTVV in routine clinical practice in the United Kingdom and the United States. VT > 8 mL/kg PBW was associated with worse patient outcomes.

High Mechanical Power and Driving Pressures are Associated With Postoperative Respiratory Failure Independent From Patients' Respiratory System Mechanics

OBJECTIVES

High mechanical power and driving pressure (ΔP) have been associated with postoperative respiratory failure (PRF) and may be important parameters guiding mechanical ventilation. However, it remains unclear whether high mechanical power and ΔP merely reflect patients with poor respiratory system mechanics at risk of PRF. We investigated the effect of mechanical power and ΔP on PRF in cohorts after exact matching by patients' baseline respiratory system compliance.

DESIGN

Hospital registry study.

SETTING

Academic hospital in New England.

PATIENTS

Adult patients undergoing general anesthesia between 2008 and 2020.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

The primary exposure was high (≥ 6.7 J/min, cohort median) versus low mechanical power and the key-secondary exposure was high (≥ 15.0 cm H 2 O) versus low ΔP. The primary endpoint was PRF (reintubation or unplanned noninvasive ventilation within seven days). Among 97,555 included patients, 4,030 (4.1%) developed PRF. In adjusted analyses, high intraoperative mechanical power and ΔP were associated with higher odds of PRF (adjusted odds ratio [aOR] 1.37 [95% CI, 1.25-1.50]; p < 0.001 and aOR 1.45 [95% CI, 1.31-1.60]; p < 0.001, respectively). There was large variability in applied ventilatory parameters, dependent on the anesthesia provider. This facilitated matching of 63,612 (mechanical power cohort) and 53,260 (ΔP cohort) patients, yielding identical baseline standardized respiratory system compliance (standardized difference [SDiff] = 0.00) with distinctly different mechanical power (9.4 [2.4] vs 4.9 [1.3] J/min; SDiff = -2.33) and ΔP (19.3 [4.1] vs 11.9 [2.1] cm H 2 O; SDiff = -2.27). After matching, high mechanical power and ΔP remained associated with higher risk of PRF (aOR 1.30 [95% CI, 1.17-1.45]; p < 0.001 and aOR 1.28 [95% CI, 1.12-1.46]; p < 0.001, respectively).

CONCLUSIONS

High mechanical power and ΔP are associated with PRF independent of patient's baseline respiratory system compliance. Our findings support utilization of these parameters for titrating mechanical ventilation in the operating room and ICU.

Decreased Utilization of Low Tidal Volume Ventilation Outside of the Intensive Care Unit as Compared to Inside

Background: Investigations into the use of low tidal volume ventilation (LTVV) have been performed for patients in emergency departments (EDs) or intensive care units (ICUs). Practice differences between the ICU and non-ICU care areas have not been described. We hypothesized that the initial implementation of LTVV would be better inside ICUs than outside. Methods: This is a retrospective observational study of patients initiated on invasive mechanical ventilation (IMV) between January 1, 2016, and July 17, 2019. Initial recorded tidal volumes after intubation were used to compare the use of LTVV between care areas. Low tidal volume was considered 6.5 cc/kg of ideal body weight (IBW) or less. The primary outcome was the initiation of low tidal volume. Sensitivity analyses used a tidal volume of 8 cc/kg of IBW or less, and direct comparisons were performed between the ICU, ED, and wards. Results: There were 6392 initiations of IMV: 2217 (34.7%) in the ICU and 4175 (65.3%) outside. LTVV was more likely to be initiated in the ICU than outside (46.5% vs 34.2%; adjusted odds ratio [aOR] 0.62, 95% confidence interval [CI] 0.56-0.71, P < .01). The ICU also had more implementation when PaO2/FiO2 ratio was less than 300, (48.0% vs 34.6%; aOR 0.59, 95% CI 0.48-0.71, P < .01). When comparing individual locations, wards had lower odds of LTVV than the ICU (aOR 0.82, 95% CI 0.70-0.96, P  =  .02), the ED had lower odds than the ICU (aOR 0.55, 95% CI 0.48-0.63, P < .01), and the ED had lower odds than the wards (aOR 0.66, 95% CI 0.56-0.77, P < .01). Interpretation: Initial low tidal volumes were more likely to be initiated in the ICU than outside. This finding remained when examining only patients with a PaO2/FiO2 ratio less than 300. Care areas outside of the ICU do not employ LTVV as often as ICUs and are, therefore, a possible target for process improvement.

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.

Elevated Driving Pressure and Elastance Does Not Increase In-Hospital Mortality Among Obese and Severely Obese Patients With Ventilator Dependent Respiratory Failure

Existing recommendations for mechanical ventilation are based on studies that under-sampled or excluded obese and severely obese individuals.

Objective

To determine if driving pressure (DP) and total respiratory system elastance (E_rs) differ among normal/overweight (body mass index [BMI] < 30 kg/m²), obese, and severely obese ventilator-dependent respiratory failure (VDRF) patients and if there any associations with clinical outcomes.

Design Setting and Participants

Retrospective observational cohort study during 2016-2018 at two tertiary care academic medical centers using electronic health record data from the first 2 full days of mechanical ventilation. The cohort was stratified by BMI classes to measure median DP, time-weighted mean tidal volume, plateau pressure, and E_rs for each BMI class.

Setting and Participants

Mechanically ventilated patients in medical and surgical ICUs.

Main Outcomes and Measures

Primary outcome and effect measures included relative risk of in-hospital mortality, ventilator-free days, ICU length of stay, and hospital length of stay with multivariable adjustment.

Results

The cohort included 3,204 patients with 976 (30.4%) and 382 (11.9%) obese and severely obese patients, respectively. Severe obesity was associated with a DP greater than or equal to 15 cm H₂O (relative risk [RR], 1.51 [95% CI, 1.26-1.82]) and E_rs greater than or equal to 2 cm H₂O/(mL/kg) (RR, 1.31 [95% CI, 1.14-1.49]). Despite elevated DP and E_rs, there were no differences in in-hospital mortality, ventilator-free days, or ICU length of stay among all three groups.

Conclusions and Relevance

Despite higher DP and E_RS among obese and severely obese VDRF patients, there were no differences in in-hospital mortality or duration of mechanical ventilation, suggesting that DP has less prognostic value in obese and severely obese VDRF patients.

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.

An alert tool to promote lung protective ventilation for possible acute respiratory distress syndrome

Objective

Computer-aided decision tools may speed recognition of acute respiratory distress syndrome (ARDS) and promote consistent, timely treatment using lung-protective ventilation (LPV). This study evaluated implementation and service (process) outcomes with deployment and use of a clinical decision support (CDS) synchronous alert tool associated with existing computerized ventilator protocols and targeted patients with possible ARDS not receiving LPV.

Materials and Methods

We performed an explanatory mixed methods study from December 2019 to November 2020 to evaluate CDS alert implementation outcomes across 13 intensive care units (ICU) in an integrated healthcare system with >4000 mechanically ventilated patients annually. We utilized quantitative methods to measure service outcomes including CDS alert tool utilization, accuracy, and implementation effectiveness. Attitudes regarding the appropriateness and acceptability of the CDS tool were assessed via an electronic field survey of physicians and advanced practice providers.

Results

Thirty-eight percent of study encounters had at least one episode of LPV nonadherence. Addition of LPV treatment detection logic prevented an estimated 1812 alert messages (41%) over use of disease detection logic alone. Forty-eight percent of alert recommendations were implemented within 2 h. Alert accuracy was estimated at 63% when compared to gold standard ARDS adjudication, with sensitivity of 85% and positive predictive value of 62%. Fifty-seven percent of survey respondents observed one or more benefits associated with the alert.

Conclusion

Introduction of a CDS alert tool based upon ARDS risk factors and integrated with computerized ventilator protocol instructions increased visibility to gaps in LPV use and promoted increased adherence to LPV.

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.

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.

A Target for Increased Mortality Risk in Critically Ill Patients: The Concept of Perpetuity

Background: Emergency medicine is acuity-based and focuses on time-sensitive treatments for life-threatening diseases. Prolonged time in the emergency department, however, is associated with higher mortality in critically ill patients. Thus, we explored management after an acuity-based intervention, which we call perpetuity, as a potential mechanism for increased risk. To explore this concept, we evaluated the impact of each hour above a lung-protective tidal volume on risk of mortality. Methods: This cohort analysis includes all critically ill, non-trauma, adult patients admitted to two academic EDs between 1 November 2013 and 30 April 2017. Cox models with time-varying covariates were developed with time in perpetuity as a time-varying covariate, defined as hours above 8 mL/kg ideal body weight, adjusted for covariates. The primary outcome was the time to in-hospital death. Results: Our analysis included 2025 patients, 321 (16%) of whom had at least 1 h of perpetuity time. A partial likelihood-ratio test comparing models with and without hours in perpetuity was statistically significant (χ²(3) = 13.83, p = 0.0031). There was an interaction between age and perpetuity (Relative risk (RR) 0.9995; 95% Confidence interval (CI₉₅): 0.9991–0.9998). For example, for each hour above 8 mL/kg ideal body weight, a 20-year-old with 90% oxygen saturation has a relative risk of death of 1.02, but a 40-year-old with 90% oxygen saturation has a relative risk of 1.01. Conclusions: Perpetuity, illustrated through the lens of mechanical ventilation, may represent a target for improving outcomes in critically ill patients, starting in the emergency department. Research is needed to evaluate the types of patients and interventions in which perpetuity plays a role.

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.

[Weaning from Mechanical Ventilation in Patients with SARS-CoV-2 Infection after Prolonged Mechanical Ventilation - First Experience]

AIM

 With the emergence of a new virus and the associated pandemic, the ICU started to see a brand new kind of patient with severe ARD. As with any disease, sometimes the discontinuation of mechanical ventilation for any reason can be difficult. As a center specializing in weaning patients after prolonged mechanical ventilation, we wanted to compare our results with weaning patients who had prolonged mechanical ventilation for other reasons than those of patients who had prolonged mechanical ventilation due to SARS-CoV-2 infection.

METHODS

 We obtained our data from WeanNet register, the weaning register of the German Institute for Lung Research (ILF). In our analysis, we included only patient data from January until July 2020, which was recorded in our in-house study files.

RESULTS

 Our analysis included data on 28 patients; 11 were treated with prolonged mechanical ventilation due to SARS-CoV-2 pneumonia, 17 had no SARS-CoV-2 infection. 81.2 % of SARS-CoV-2 patients were successfully weaned from invasive ventilator therapy compared to 76.4 % of patients without SARS-CoV-2. Mortality in the SARS-CoV-2 group was 18.2 % compared to 11.8 % in the other group. Patients with SARS-CoV-2 infections were predominantly males with preexisting cardiovascular disease or a history of nicotine abuse. ARDS was the most common cause of respiratory failure which led to primary intubation.

CONCLUSION

 Even though we were only able to analyze a small number of patient histories due to the novelty of the disease, we were able to show that patients with prolonged mechanical ventilation after SARS-CoV-2 infection can be equally successfully weaned compared to patients with prolonged mechanical ventilation due to other diseases. Risk factors for prolonged mechanical ventilation after a severe case of SARS-CoV-2 infection seemed to be male gender, nicotine abuse and cardiovascular disease.

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.

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.

Opportunities to Improve the Capacity to Rescue: Intraoperative and Perioperative Tools

Postoperative complications, which occur in approximately 23% of surgeries, are a major source of patient mortality. Some of these deaths may be preventable. This article explores factors and contexts during the intraoperative period, in the postanesthesia care unit, perioperatively, and after discharge that may represent opportunities to intervene and prevent mortality after a potentially treatable complication. Tools to improve the identification and response to life-threatening complications in these unique care settings are discussed.

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.

Novel approaches to facilitate the implementation of guidelines in the ICU

The effective implementation of evidence-based recommendations in routine intensive care unit (ICU) practice is challenging. Barriers related to the proposed recommendations, local contexts and processes can make the adoption of evidence-based practices difficult, contributing to healthcare inefficiency and worse patient and family outcomes. This review discusses the common barriers to guideline implementation in critical care settings, explores how implementation science provides an important framework for guiding implementation interventions, and discusses some specific and proven implementation strategies to improve adherence to evidence-based practices in the ICU.

Causes and characteristics of death in patients with acute hypoxemic respiratory failure and acute respiratory distress syndrome: a retrospective cohort study

Background

Acute hypoxemic respiratory failure (AHRF) and acute respiratory distress syndrome (ARDS) are associated with high in-hospital mortality. However, in cohorts of ARDS patients from the 1990s, patients more commonly died from sepsis or multi-organ failure rather than refractory hypoxemia. Given increased attention to lung-protective ventilation and sepsis treatment in the past 25 years, we hypothesized that causes of death may be different among contemporary cohorts. These differences may provide clinicians with insight into targets for future therapeutic interventions.

Methods

We identified adult patients hospitalized at a single tertiary care center (2016–2017) with AHRF, defined as PaO₂/FiO₂ ≤ 300 while receiving invasive mechanical ventilation for > 12 h, who died during hospitalization. ARDS was adjudicated by multiple physicians using the Berlin definition. Separate abstractors blinded to ARDS status collected data on organ dysfunction and withdrawal of life support using a standardized tool. The primary cause of death was defined as the organ system that most directly contributed to death or withdrawal of life support.

Results

We identified 385 decedents with AHRF, of whom 127 (33%) had ARDS. The most common primary causes of death were sepsis (26%), pulmonary dysfunction (22%), and neurologic dysfunction (19%). Multi-organ failure was present in 70% at time of death, most commonly due to sepsis (50% of all patients), and 70% were on significant respiratory support at the time of death. Only 2% of patients had insupportable oxygenation or ventilation. Eighty-five percent died following withdrawal of life support. Patients with ARDS more often had pulmonary dysfunction as the primary cause of death (28% vs 19%; p = 0.04) and were also more likely to die while requiring significant respiratory support (82% vs 64%; p <  0.01).

Conclusions

In this contemporary cohort of patients with AHRF, the most common primary causes of death were sepsis and pulmonary dysfunction, but few patients had insupportable oxygenation or ventilation. The vast majority of deaths occurred after withdrawal of life support. ARDS patients were more likely to have pulmonary dysfunction as the primary cause of death and die while requiring significant respiratory support compared to patients without ARDS.

Electronic "Sniffer" Systems to Identify the Acute Respiratory Distress Syndrome

BACKGROUND

The acute respiratory distress syndrome (ARDS) results in substantial mortality but remains underdiagnosed in clinical practice. Automated ARDS "sniffer" systems, tools that can automatically analyze electronic medical record data, have been developed to improve recognition of ARDS in clinical practice.

OBJECTIVES

To perform a systematic review examining the evidence underlying automated sniffer systems for ARDS detection.

DATA SOURCES

MEDLINE and Scopus databases through November 2018 to identify studies of tools using routinely available clinical data to detect patients with ARDS.

DATA EXTRACTION

Study design, tool description, and diagnostic performance were extracted by two reviewers. The Quality Assessment of Diagnostic Accuracy Studies-2 was used to evaluate each study for risk of bias in four domains: patient selection, index test, reference standard, and study flow and timing.

SYNTHESIS

Among 480 studies identified, 9 met inclusion criteria, and they evaluated six unique ARDS sniffer tools. Eight studies had derivation and/or temporal validation designs, with one also evaluating the effects of implementing a tool in clinical practice. A single study performed an external validation of previously published ARDS sniffer tools. Studies reported a wide range of sensitivities (43-98%) and positive predictive values (26-90%) for detection of ARDS. Most studies had potential for high risk of bias identified in their study design, including patient selection (five of nine), reference standard (four of nine), and flow and timing (three of nine). In the single external validation without any perceived risks of biases, the performance of ARDS sniffer tools was worse.

CONCLUSIONS

Sniffer systems developed to detect ARDS had moderate to high predictive value in their derivation cohorts, although most studies had the potential for high risks of bias in study design. Methodological issues may explain some of the variability in tool performance. There remains an ongoing need for robust evaluation of ARDS sniffer systems and their impact on clinical practice. Systematic review registered with PROSPERO (CRD42015026584).

ggalluvial: Layered Grammar for Alluvial Plots

Alluvial diagrams use stacked bar plots and variable-width ribbons to represent multi-dimensional or repeated-measures data comprising categorical or ordinal variables (Bojanowski & Edwards, 2016; Rosvall & Bergstrom, 2010). The ggalluvial package extends the layered grammar of graphics of ggplot2 (Wickham, 2016) to generate alluvial diagrams from tidy data (Wickham, 2014). The package makes two key contributions to the R ecosystem. First, ggalluvial anchors the imprecise notion of an alluvial diagram to the rigid grammar of graphics (Wilkinson, 2006), which lends the plots more precise meaning and opens up many combinatorial possibilities. Second, ggalluvial adopts a distinctive geological nomenclature to distinguish "alluvial plots" and their graphical elements from Sankey diagrams and parallel sets plots, which I hope prove useful as these visualization tools converge toward common standards.

Emerging concepts in ventilation-induced lung injury

Ventilation-induced lung injury results from mechanical stress and strain that occur during tidal ventilation in the susceptible lung. Classical descriptions of ventilation-induced lung injury have focused on harm from positive pressure ventilation. However, injurious forces also can be generated by patient effort and patient–ventilator interactions. While the role of global mechanics has long been recognized, regional mechanical heterogeneity within the lungs also appears to be an important factor propagating clinically significant lung injury. The resulting clinical phenotype includes worsening lung injury and a systemic inflammatory response that drives extrapulmonary organ failures. Bedside recognition of ventilation-induced lung injury requires a high degree of clinical acuity given its indistinct presentation and lack of definitive diagnostics. Yet the clinical importance of ventilation-induced lung injury is clear. Preventing such biophysical injury remains the most effective management strategy to decrease morbidity and mortality in patients with acute respiratory distress syndrome and likely benefits others at risk.

Adoption of low tidal volume ventilation in the emergency department: A quality improvement intervention

BACKGROUND

Ventilator tidal volumes of >8 mL/kg of predicted body weight (PBW) may increase the risk of lung injury. We sought to evaluate the impact of a quality improvement intervention among intubated Emergency Department (ED) patients to protocolize the prescription of low tidal volume ventilation.

METHODS

In this before-and-after study, the average tidal volume delivered to ED patients receiving volume assist-control ventilation was compared before (2007-2014) and after (2015-2016) implementation of a ventilator initiation protocol (the quality improvement intervention). The intervention emphasized 1) measurement of the patient's height to calculate PBW and therefore tailor the tidal volume to estimated lung size (<8 mL/kg PBW), and 2) focused education and reference materials for ED physicians and respiratory therapists.

RESULTS

Among ventilated ED patients meeting inclusion criteria in the before (N = 2185) and after (N = 774) cohorts, the mean (±SD) tidal volume decreased from 9.0 ± 1.4 mL/kg to 7.2 ± 0.9 mL/kg PBW following the intervention (absolute difference 1.8 mL/kg, 95% confidence interval 1.7 to 1.9 mL/kg, p < 0.001). The proportion of patients receiving low tidal volume ventilation increased after the intervention (72%), as compared to before (23%). Low tidal volume ventilation continued to be utilized at 24 h after ICU admission in patients who remained intubated in the cohort following the intervention (mean tidal volume 7.3 mL/kg PBW).

CONCLUSIONS

Pairing a ventilator initiation protocol with focused education and resources for emergency physicians and respiratory therapists was associated with a significant reduction in tidal volume delivered to ED patients.