Effects of adding hi̇gh flow oxygenation therapy to non-invasive mechanical ventilation therapy in patients with chronic obstructive pulmonary disease exacerbation diagnosis in the anesthesia intensive care unit

The use of high-flow oxygenation (HFO) additional to non-invasive mechanical ventilation (NIMV) in acute exacerbations of chronic obstructive pulmonary disease (AECOPD) patients requiring intensive care unit (ICU) admission has not been clarified yet. The aim of this study is to investigate the effects of HFO in addition to NIMV in patients with AECOPD on oxygenation, carbon-dioxide removal, intubation rate, time to the start of nutrition, durations of invasive mechanical ventilation (IMV), ICU / hospital stays and mortality. After ethical committee approval, this study was planned as a retrospective cohort study of patients whom were admitted to Hacettepe University Hospital Anesthesiology ICU with AECOPD and required NIMV between 1st January 2015- 31st December 2019. Patients were grouped as NIMV/HFO or NIMV/Supplemental oxygen therapy (SOT) according to the use of HFO or SOT additional to the NIMV therapy. Patients' demographics, coexisting diseases, results of arterial blood gas analysis, pharmacologic treatment features, oxygenation, time and ratio of re-intubation, time to the start of nutrition, durations of invasive mechanical ventilation, ICU and hospital stay, 28th day and 90th day mortality rates were retrospectively gathered from patients' files and electronic records. Statistical differences were tested with Mann-Whitney U, Chi-square and ANOVA tests. During the five-year period studied, among the 148 AECOPD patients in the ICU, 28 patients received NIMV/HFO and 32 patients received NIMV/SOT. Both groups were similar regarding demographics, coexisting diseases and the pharmacologic treatments they received. Oxygenation improved and Ph values normalized similarly in the two groups, 2 and 12 hours after the ICU admission. In the NIMV/HFO group oxygenation was better (median [interquartile range] PaO2 89 [88-100] mmHg vs 79 [71 -83] mmHg, p=0.019) but hypercarbia was worse (PaCO2 68 [54-71] mmHg vs 53 [49-64] mmHg, p=0.043) than NIMV/SOT group at 48th hour. Patients in the NIMV/HFO group were able to fed earlier than the NIMV/SOT group (3 [3-4] days vs 5 [4-8] days, respectively, p<0,001). The combined use of NIMV and HFO did not significantly change intubation rate, durations of IMV, ICU and hospital stay, and mortality rates when compared to NIMV/SOT. We conclude that, in patients with AECOPD requiring ICU admission, in addition to NIMV, the use of HFO instead of SOT, improves oxygenation on the second day and is associated with earlier start of nutrition. The additional use of HFO does not change the intubation rates, durations of IMV, ICU and hospital stay, and mortality rates. Keywords: COPD exacerbation, intensive care, mechanical ventilation, HFNO