Impact of high-flow oxygen therapy vs non-invasive ventilation on gas exchange and respiratory rate in patients with acute decompensated chronic heart failure and acute respiratory failure

Abstract

Background Acute respiratory failure (ARF) is a frequent complication of acute decompensation of chronic heart failure (ADCHF) and significantly worsens prognosis. High-flow oxygen therapy (HFOT) and non-invasive ventilation (NIV) are commonly used to correct hypoxemia; however, comparative data on their effects on gas exchange, respiratory rate, oxygenation index, and patient tolerance in this population remain limited. Aim To compare the effects of HFOT and NIV on gas exchange parameters, respiratory rate, oxygenation index, and therapy tolerance in patients with ADCHF complicated by ARF. Methods This single-center randomized study was conducted from September 2022 to September 2023 in the cardiac intensive care units of our University Clinical Hospital. Among 270 hospitalized patients with ARF, 108 met the inclusion criteria, and 68 completed the full treatment protocol. Patients were randomized into two groups: HFOT (n=34) and NIV (n=34). Key physiological parameters were monitored at admission and at 1, 6, and 24 hours after therapy initiation. Primary outcomes included PaO₂, PaCO₂, respiratory rate (RR), SpO₂, and oxygenation index (OI). Therapy tolerance was assessed using a 10-point visual analog scale (VAS). Statistical significance was set at p0.05). PaCO₂ decreased by 1–3% and 4–5%, RR decreased by 15–16% and 12–15%, SpO₂ increased by 15–18% and 15–17%, and OI increased by 14–33% and 8–17%, respectively (p>0.05). At 6 hours, further improvement was observed: PaO₂ increased by 52% in both groups (HFOT 101–127 mmHg, NIV 103–131 mmHg), PaCO₂ decreased by 5–10%, RR decreased by 23–29%, SpO₂ reached 97–99%, and OI was 308–362 and 303–337 units, respectively. At 24 hours, parameters stabilized: PaO₂ 94–97 and 92–97 mmHg, PaCO₂ 37–45 and 37–52 mmHg, RR 18–18 and 18–19 breaths/min, SpO₂ 98–99% in both groups, OI 313–327 and 312–329 units. Differences between groups were not statistically significant (p>0.05). Therapy tolerance was better in the HFOT group: moderate-to-severe discomfort (VAS>3) was reported in 36.7% of patients versus 63.3% in the NIV group (p=0.042). No serious adverse events were observed in either group. Conclusions Both HFOT and NIV effectively improve gas exchange and reduce respiratory rate in patients with ADCHF complicated by ARF. HFOT is associated with higher therapy tolerance and fewer reports of discomfort. Both methods are safe and can be applied early in the course of acute decompensated heart failure to optimize patient outcomes.