Intensivists' response to hyperoxemia in mechanical ventilation patients: The status quo and related factors

BACKGROUND: Due to the still sparse literature in China, the investigation of hyperoxemia management is required. Thus, we aim to conduct a retrospective study to provide more information about hyperoxemia management in intensive care unit (ICU) patients. METHODS: We retrospectively screened the medical records of adult patients (age >= 18 years) who required mechanical ventilation (MV) >= 24 hours from January 1, 2018, to December 31, 2018. All arterial blood gas (ABG) tested during MV was retrieved, and MV settings were recorded. The median arterial partial pressure of oxygen (PaO2) >120 mmHg (1 mmHg=0.133 kPa) was defined as mild to moderate hyperoxemia, and PaO2 >300 mmHg as extreme hyperoxemia. Intensivists' response to hyperoxemia was assessed based on the reduction of fraction of inspired oxygen (FiO(2)) within one hour after hyperoxemia was recorded. Multivariable logistic regression analysis was performed to determine the independent factors associated with the intensivists' response to hyperoxemia. RESULTS: A total of 592 patients were finally analyzed. The median Acute Physiology and Chronic Health Evaluation II (APACHE II) score was 21 (15-26). The PaO2, arterial oxygen saturation (SaO(2)), FiO(2), and positive end expiratory pressure (PEEP) were 96.4 (74.0-126.0) mmHg, 97.8% (95.2%-99.1%), 0.4 (0.4-0.5), and 5 (3-6) cmH(2)O, respectively. Totally 174 (29.39%) patients had PaO2 >120 mmHg, and 19 (3.21%) patients had extreme hyperoxemia at PaO2 >300 mmHg. In cases of mild to moderate hyperoxemia with FiO(2) <= 0.4, only 13 (2.20%) patients had a decrease in FiO(2) within one hour. The multivariable logistic regression analysis showed that a positive response was independently associated with FiO(2) (odds ratio [OR] 1.09, 95% confidence interval [CI] 1.06-1.12, P<0.001), PaO2 (OR 1.01, 95% CI 1.00-1.01, P=0.002), and working shifts (OR 5.09, 95% CI 1.87-13.80, P=0.001). CONCLUSIONS: Hyperoxemia occurs frequently and is neglected in most cases, particularly when mild to moderate hyperoxemia, hyperoxemia with lower FiO(2), hyperoxemia during night and middle-night shifts, or FiO(2) less likely to be decreased. Patients may be at a risk of oxygen toxicity because of the liberal oxygen strategy. Therefore, further research is needed to improve oxygen management for patients with MV in the ICUs.