Peri-operative use of high-flow nasal oxygen in obstetric patients: a systematic review.

INTRODUCTION High-flow nasal oxygen devices have gained interest in pre-oxygenation and peri-operative oxygenation strategies. However, their role in obstetric anaesthesia remains poorly defined. This systematic review aimed to evaluate the use of high-flow nasal oxygen in obstetric patients during the peri-operative period, focusing on maternal oxygenation and clinical outcomes. METHODS We included studies published in any language, conducted in all countries. Search terms included terminology concerning obstetric anaesthesia related to the use of high-flow nasal oxygen in the peri-operative period. Included papers were assessed for risk of bias. Studies were included for detailed review if they evaluated the use of high-flow nasal oxygen as a pre-oxygenation strategy in obstetric patients and reported maternal or neonatal outcomes. RESULTS A total of 649 abstracts were screened with 11 articles included. There was variation in pre-oxygenation strategies and primary outcomes. Available evidence suggests that high-flow nasal oxygen was not superior to facemask pre-oxygenation in achieving target end-tidal oxygen concentrations. High-flow nasal oxygen may increase the partial pressure of oxygen in arterial blood, but the evidence of increased apnoea time was inconsistent. There were no reported adverse maternal effects or differences in neonatal Apgar scores, umbilical cord gases or fetal heart rate assessments. DISCUSSION The advantages of peri-operative high-flow nasal oxygen over conventional oxygenation methods for obstetric patients remain uncertain. Current evidence does not show a clear benefit of high-flow nasal oxygen in achieving pre-oxygenation targets or prolonging time to desaturation in low-risk patients, whilst the benefits in high-risk patients remain uncertain and warrant further investigation.