External Validity of Electronic Sniffers for Automated Recognition of Acute Respiratory Distress Syndrome.

INTRODUCTION: Automated electronic sniffers may be useful for early detection of acute respiratory distress syndrome (ARDS) for institution of treatment or clinical trial screening. METHODS: In a prospective cohort of 2929 critically ill patients, we retrospectively applied published sniffer algorithms for automated detection of acute lung injury to assess their utility in diagnosis of ARDS in the first 4 ICU days. Radiographic full-text reports were searched for "edema" OR ("bilateral" AND "infiltrate") and a more detailed algorithm for descriptions consistent with ARDS. Patients were flagged as possible ARDS if a radiograph met search criteria and had a PaO2/FiO2 or SpO2/FiO2 of 300 or 315, respectively. Test characteristics of the electronic sniffers and clinical suspicion of ARDS were compared to a gold standard of 2-physician adjudicated ARDS. RESULTS: Thirty percent of 2841 patients included in the analysis had gold standard diagnosis of ARDS. The simpler algorithm had sensitivity for ARDS of 78.9%, specificity of 52%, positive predictive value (PPV) of 41%, and negative predictive value (NPV) of 85.3% over the 4-day study period. The more detailed algorithm had sensitivity of 88.2%, specificity of 55.4%, PPV of 45.6%, and NPV of 91.7%. Both algorithms were more sensitive but less specific than clinician suspicion, which had sensitivity of 40.7%, specificity of 94.8%, PPV of 78.2%, and NPV of 77.7%. CONCLUSIONS: Published electronic sniffer algorithms for ARDS may be useful automated screening tools for ARDS and improve on clinical recognition, but they are limited to screening rather than diagnosis because their specificity is poor.

Best PEEP trials are dependent on tidal volume.

Determining the optimal positive end-expiratory pressure (PEEP) in patients with acute respiratory distress syndrome remains an area of active investigation. Most trials individualizing PEEP optimize one physiologic parameter (e.g., driving pressure) by titrating PEEP while holding other ventilator settings constant. Optimal PEEP, however, may depend on the tidal volume, and changing the tidal volume with which a best PEEP trial is performed may lead to different best PEEP settings in the same patient. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02871102. Registered on 12 August 2016.

Preadmission Oral Corticosteroids Are Associated With Reduced Risk of Acute Respiratory Distress Syndrome in Critically Ill Adults With Sepsis.

OBJECTIVES: To determine the association between preadmission oral corticosteroid receipt and the development of acute respiratory distress syndrome in critically ill patients with sepsis. DESIGN: Retrospective observational study. SETTING: Medical, surgical, trauma, and cardiovascular ICUs of an academic medical center. PATIENTS: A total of 1,080 critically ill patients with sepsis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The unadjusted occurrence rate of acute respiratory distress syndrome within 96 hours of ICU admission was 35% among patients who had received oral corticosteroids compared with 42% among those who had not (p = 0.107). In a multivariable analysis controlling for prespecified confounders, preadmission oral corticosteroids were associated with a lower incidence of acute respiratory distress syndrome in the 96 hours after ICU admission (odds ratio, 0.53; 95% CI, 0.33-0.84; p = 0.008), a finding that persisted in multiple sensitivity analyses. The median daily dose of oral corticosteroids among the 165 patients receiving oral corticosteroids, in prednisone equivalents, was 10 mg (interquartile range, 5-30 mg). Higher doses of preadmission oral corticosteroids were associated with a lower incidence of acute respiratory distress syndrome (odds ratio for 30 mg of prednisone compared with 5 mg 0.53; 95% CI, 0.32-0.86). In multivariable analyses, preadmission oral corticosteroids were not associated with in-hospital mortality (odds ratio, 1.41; 95% CI, 0.87-2.28; p = 0.164), ICU length of stay (odds ratio, 0.90; 95% CI, 0.63-1.30; p = 0.585), or ventilator-free days (odds ratio, 1.06; 95% CI, 0.71-1.57; p = 0.783). CONCLUSIONS: Among ICU patients with sepsis, preadmission oral corticosteroids were independently associated with a lower incidence of early acute respiratory distress syndrome.

Randomized Trial of Apneic Oxygenation during Endotracheal Intubation of the Critically Ill.

RATIONALE: Hypoxemia is common during endotracheal intubation of critically ill patients and may predispose to cardiac arrest and death. Administration of supplemental oxygen during laryngoscopy (apneic oxygenation) may prevent hypoxemia. OBJECTIVES: To determine if apneic oxygenation increases the lowest arterial oxygen saturation experienced by patients undergoing endotracheal intubation in the intensive care unit. METHODS: This was a randomized, open-label, pragmatic trial in which 150 adults undergoing endotracheal intubation in a medical intensive care unit were randomized to receive 15 L/min of 100% oxygen via high-flow nasal cannula during laryngoscopy (apneic oxygenation) or no supplemental oxygen during laryngoscopy (usual care). The primary outcome was lowest arterial oxygen saturation between induction and 2 minutes after completion of endotracheal intubation. MEASUREMENTS AND MAIN RESULTS: Median lowest arterial oxygen saturation was 92% with apneic oxygenation versus 90% with usual care (95% confidence interval for the difference, -1.6 to 7.4%; P = 0.16). There was no difference between apneic oxygenation and usual care in incidence of oxygen saturation less than 90% (44.7 vs. 47.2%; P = 0.87), oxygen saturation less than 80% (15.8 vs. 25.0%; P = 0.22), or decrease in oxygen saturation greater than 3% (53.9 vs. 55.6%; P = 0.87). Duration of mechanical ventilation, intensive care unit length of stay, and in-hospital mortality were similar between study groups. CONCLUSIONS: Apneic oxygenation does not seem to increase lowest arterial oxygen saturation during endotracheal intubation of critically ill patients compared with usual care. These findings do not support routine use of apneic oxygenation during endotracheal intubation of critically ill adults. Clinical trial registered with www.clinicaltrials.gov (NCT 02051816).

Predicting Major Adverse Kidney Events among Critically Ill Adults Using the Electronic Health Record.

Prediction of major adverse kidney events in critically ill patients may help target therapy, allow risk adjustment, and facilitate the conduct of clinical trials. In a cohort comprised of all critically ill adults admitted to five intensive care units at a single tertiary care center over one year, we developed a logistic regression model for the outcome of Major Adverse Kidney Events within 30 days (MAKE30), the composite of persistent renal dysfunction, new renal replacement therapy (RRT), and in-hospital mortality. Proposed risk factors for the MAKE30 outcome were selected a priori and included age, race, gender, University Health System Consortium (UHC) expected mortality, baseline creatinine, volume of isotonic crystalloid fluid received in the prior 24 h, admission service, intensive care unit (ICU), source of admission, mechanical ventilation or receipt of vasopressors within 24 h of ICU admission, renal replacement therapy prior to ICU admission, acute kidney injury, chronic kidney disease as defined by baseline creatinine value, and renal failure as defined by the Elixhauser index. Among 10,983 patients in the study population, 1489 patients (13.6%) met the MAKE30 endpoint. The strongest independent predictors of MAKE30 were UHC expected mortality (OR 2.32 [95%CI 2.06-2.61]) and presence of acute kidney injury at ICU admission (OR 4.98 [95%CI 4.12-6.03]). The model had strong predictive properties including excellent discrimination with a bootstrap-corrected area-under-the-curve (AUC) of 0.903, and high precision of calibration with a mean absolute error prediction of 1.7%. The MAKE30 composite outcome can be reliably predicted from factors present within 24 h of ICU admission using data derived from the electronic health record.

Risk Factors for and Prediction of Hypoxemia during Tracheal Intubation of Critically Ill Adults.

RATIONALE: Hypoxemia is a common complication during tracheal intubation of critically ill adults and is a frequently used endpoint in airway management research. Identifying patients likely to experience low oxygen saturations during tracheal intubation may be useful for clinical practice and clinical trials. OBJECTIVES: To identify risk factors for lower oxygen saturations and severe hypoxemia during tracheal intubation of critically ill adults and develop prediction models for lowest oxygen saturation and hypoxemia. METHODS: Using data on 433 intubations from two randomized trials, we developed linear and logistic regression models to identify preprocedural risk factors for lower arterial oxygen saturations and severe hypoxemia between induction and 2 minutes after intubation. Penalized regression was used to develop prediction models for lowest oxygen saturation after induction and severe hypoxemia. A simplified six-point score was derived to predict severe hypoxemia. RESULTS: Among the 433 intubations, 426 had complete data and were included in the model. The mean (standard deviation) lowest oxygen saturation was 88% (14%); median (interquartile range) was 93% (83-98%). Independent predictors of severe hypoxemia included hypoxemic respiratory failure as the indication for intubation (odds ratio [OR], 2.70; 95% confidence interval [CI], 1.58-4.60), lower oxygen saturation at induction (OR, 0.92 per 1% increase; 95% CI, 0.89-0.96 per 1% increase), younger age (OR, 0.97 per 1-year increase; 95% CI, 0.95-0.99 per 1-year increase), higher body mass index (OR, 1.03 per 1 kg/m2; 95% CI, 1.00-1.06 per 1 kg/m2), race (OR, 4.58 for white vs. black; 95% CI, 1.97-10.67; OR, 4.47 for other vs. black; 95% CI, 1.19-16.84), and operator with fewer than 100 prior intubations (OR, 2.83; 95% CI, 1.37-5.85). A six-point score using the identified risk factors predicted severe hypoxemia with an area under the receiver operating curve of 0.714 (95% CI, 0.653 to 0.778). CONCLUSIONS: Lowest oxygen saturation and severe hypoxemia during tracheal intubation in the intensive care unit can be accurately predicted using routinely available preprocedure clinical data, with saturation at induction and hypoxemic respiratory failure being the strongest predictors. A simple bedside score may identify patients at risk for hypoxemia during intubation to help target preventative interventions and facilitate enrichment in clinical trials.