We studied mechanically ventilated patients admitted to the emergency departments (EDs) or intensive care units (ICUs) of participating study hospitals, which were part of the NIH Prevention and Early Treatment of Acute Lung Injury (PETAL) Network. We excluded children, pregnant women, and prisoners. At the time a clinical ABG was obtained for a ventilated patient, the nurse or respiratory therapist obtaining the ABG completed a brief case report form (CRF) that included current SpO2, quality of the oximeter waveform, skin pigmentation (graded informally from very light to very dark, on a 5-point ordinal span, with reference skin pigments included on the CRF). Research coordinators then documented age, sex, body mass index (BMI), body temperature (as measured clinically, without preference for core vs. peripheral temperature measurements), ABG results, basic metabolic panel results, hemoglobin, Positive End Expiratory Pressure (PEEP), FIO2, tidal volume, receipt of vasopressors (i.e., epinephrine, norepinephrine, phenylephrine, dopamine, or vasopressin) at the time the ABG was obtained, and whether the patient met consensus criteria for ARDS other than hypoxemia. Specifically, site investigators individually reviewed chest radiographs and the medical record to assess whether ARDS criteria (acute onset of bilateral lung opacities not fully explained by effusions, lobar/lung collapse, or nodules) other than hypoxemia were met. ARDS was then considered present if the PaO2/FIO2 met relevant thresholds. Given resource constraints, we did not require a specific ABG sampling strategy or collect denominator data on the total number of ABGs performed in participating hospitals.
Data were uploaded to the Clinical Coordinating Center (CCC) at Massachusetts General Hospital, where quality analysis and cleaning were undertaken according to standard procedures. Each participating Institutional Review Board (IRB), including the CCC IRB, approved this study with waiver of informed consent on the basis of compliance with 45 CFR 46.116d.
Data were uploaded to the Clinical Coordinating Center (CCC) at Massachusetts General Hospital, where quality analysis and cleaning were undertaken according to standard procedures. Each participating Institutional Review Board (IRB), including the CCC IRB, approved this study with waiver of informed consent on the basis of compliance with 45 CFR 46.116d.
