High-flow nasal cannula oxygen versus Venturi facemask in women with cardiovascular disease undergoing cesarean delivery under neuraxial anesthesia: a randomized controlled trial.

BACKGROUND

Women with cardiovascular disease undergoing cesarean delivery under neuraxial anesthesia are vulnerable to perioperative hypoxemia, particularly during sedation after fetal delivery. We compared high-flow nasal cannula oxygen (HFNC) with Venturi facemask oxygen in this setting.

METHODS

In this prospective single-blind randomized controlled trial, 44 women with cardiovascular disease undergoing elective cesarean delivery under neuraxial anesthesia were randomly assigned to HFNC [40 L/min, fraction of inspired oxygen (FiO2) 0.40] or Venturi facemask oxygen (10 L/min, FiO2 0.40). Remimazolam sedation was initiated 5 min after fetal delivery. The primary outcome was maternal arterial partial pressure of oxygen (PaO2) measured 10 min after achievement of the target sedation level. Secondary outcomes included perioperative oxygenation and ventilation variables, hemodynamic variables, airway or oxygenation-related interventions, maternal recovery outcomes, neonatal outcomes, postoperative biomarkers, and tolerance to the oxygen delivery device. Between-group comparisons were performed using appropriate parametric or non-parametric tests, and effect estimates were reported with 95% confidence intervals (CIs).

RESULTS

All 44 randomized participants were included in the final analysis. During sedation, PaO2 was significantly higher in the HFNC group than in the facemask group (177.3±40.9 vs. 137.5±37.6 mmHg), with an adjusted mean difference of 48.8 mmHg (95% CI: 29.8 to 67.8; P<0.001). Minimum intraoperative peripheral oxygen saturation (SpO2) was also higher with HFNC [99% (98-99%) vs. 98% (96-98%); Hodges-Lehmann difference 1.0%, 95% CI: 0.0-2.0%; P=0.02]. Arterial partial pressure of carbon dioxide (PaCO2) during sedation did not differ significantly between groups. The incidence of hypotension, vasoactive drug use, airway interventions, postoperative organ injury markers, oxygen-interface tolerance scores, intensive care unit (ICU) admission, and neonatal outcomes were similar. Postoperative B-type natriuretic peptide (BNP) was numerically lower in the HFNC group after baseline adjustment, but the difference was not statistically significant [geometric mean ratio 0.67, 95% CI: 0.42-1.08; P=0.10].

CONCLUSIONS

In women with cardiovascular disease undergoing cesarean delivery under neuraxial anesthesia, HFNC significantly improved maternal PaO2 during remimazolam sedation after fetal delivery compared with Venturi facemask oxygen. This physiological improvement was not accompanied by statistically significant reductions in airway interventions, maternal complications, ICU admission, or adverse neonatal outcomes. Larger studies powered for clinical outcomes are needed.

TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR2400087925.