HYPEROXIA IN MECHANICALLY VENTILATED PATIENTS AND RELATIONSHIP TO FIO2 PRACTICES

Abstract

SESSION TITLE: ARDS: Fine-tuning Details in Management SESSION TYPE: Original Investigations PRESENTED ON: 10/21/2019 1:30 PM - 2:30 PM PURPOSE: In patients with respiratory failure, hypoxia is more widely recognized and responded to than hyperoxia. But hyperoxia can result in increased inflammatory cells and pulmonary permeability causing lung injury, decreased cardiac output and generation of free radicals causing more oxidative injury. Current guidelines from the British Thoracic Society recommend oxygen be given to achieve a target saturation of 94-98% for most acutely ill patients and 88-92% for those at risk for hypercapnic respiratory failure. In this study we aimed to examine: 1) The percent time mechanically ventilated (MV) patients spent in hyperoxia defined as a peripheral capillary oxygen saturation (SpO2) greater than or equal to 98% and 2) Whether high SpO2 levels correlate with adjustments in ventilator management of fraction of inspired oxygen (FiO2). METHODS: In a retrospective cohort study of data obtained from three hospitals in New York City from patients with respiratory failure, SpO2 and FiO2 were extracted for adult patients admitted to the ICU in 2017 and requiring MV for greater than or equal to 24 hours. In cases of multiple intubations and/or hospitalizations for a single patient, data was examined for a single and first episode of MV. RESULTS: For a total of 1,431 patients with MV greater than or equal to 24 hours, there were 254,373 recorded occurrences of SpO2 and the median SpO2 was 99% (IQR 96-100%) with patients spending a median of 73% of their time on MV with SpO2> 98% (IQR 46-90%) Moreover, for these patients, the median FiO2 of all recorded values was 40% (IQR 40-50%). When examining patients based on the percent time spent with a SpO2 >98%, the quartile of patients who spent the least duration of time at SpO2 > 98% (0-46% of MV time with a SpO2 >98% ), the median FiO2 was 50% (IQR 40-60%). Quartile 2 patients spent 46-73% of MV time with a SpO2 >98% and had a median FiO2 of 40% (IQR 40-50%). Similarly, Quartile 3 (73-90% of MV time with a SpO2 >98%) and 4 (>90% of MV time with a SpO2 >98%) had median FiO2 of 40% (IQR 40-45%, 35-40% respectively). CONCLUSIONS: The patients in our cohort spent more than half of their MV time hyperoxic with SpO2 >/= 98% at mostly 40% FiO2 which did not seem to vary with the percentage of time patients spent in hyperoxia. This suggest that clinicians are not significantly changing the amount of FiO2 based on SpO2 for this cohort and that there is minimal attempts to lower FiO2 below 40% even if patients are hyperoxic and do not need nor benefit from this level of oxygen. CLINICAL IMPLICATIONS: Further research is needed in examining whether hyperoxia results in adverse outcomes and whether lowering FiO2 below 40% routinely can save hospital costs without adversely affecting patient outcome. DISCLOSURES: No relevant relationships by Nikita Agrawal, source=Web Response No relevant relationships by Jen-Ting Chen, source=Web Response No relevant relationships by Michelle Gong, source=Web Response No relevant relationships by YUE TANG, source=Web Response