Effects of Supplemental Oxygen on Maternal and Neonatal Oxygenation in Elective Cesarean Section under Spinal Anesthesia: A Randomized Controlled Trial

Abstract

The use of supplemental oxygen in uncomplicated cesarean deliveries under spinal anesthesia has been thoroughly investigated during recent decades. The aim of this study was to determine the benefits for both mother and infant of administering supplemental, low-dose oxygen via a nasal cannula versus having no supplement (i.e., room air only). Healthy parturients at term undergoing elective cesarean section under spinal anesthesia were randomly allocated into two groups: an oxygen group (n = 170), who received 3 LPM oxygen via a nasal cannula; and a room-air group (n = 170), who were assigned to breathe room air. Maternal oxygen saturation was measured continuously by using pulse oximeter. The desaturation was determined by oxygen saturation <94% over 30 seconds. Umbilical cord gases and Apgar scores were collected followed delivery of the infant. All maternal desaturation events occurred in 12 parturients assigned to the room-air group. Most events were concurrent with hypotension. The umbilical venous partial pressure of oxygen was significantly higher in the oxygen group. The other blood gas measurements and Apgar scores were not significantly different between the two groups. Based on our findings, the use of supplemental oxygen could prevent maternal desaturation resulting from receiving sedation and intraoperative hypotension.

Incidence of Maternal Desaturation among Patients Undergoing Elective Caesaraen Section under Regional Anaesthesia

“…Similar to other studies, there was no evidence of decompensation in short term clinical outcome (10,20). All episodes of oxygen desaturation were attended to promptly and managed appropriately to minimize the duration of desaturation and/or hypotension.…”

“…Our incidence of 1.2% is low compared to 3.7% and 7.4% in two recent studies (10,17). In our study, all three episodes of desaturation were associated with hypotension, similar to the study by Siriussawakul et al who reported that nine out of twelve events were attributed to intraoperative hypotension and the other three due to sedatives administration (10). In contrast, a much higher incidence of desaturation following regional anaesthesia (75-87%) was seen in studies involving non-obstetric surgeries (18,19).…”

“…Studies on maternal oxygen saturation during regional anaesthesia for CS often involved only healthy, non obese subjects (4,(8)(9)(10). In our prospective observational study, we included patients with BMI > 30 kg/m2 at first antenatal consultation and compared them with their non obese counterparts.…”

“…Hypoxaemia has been defined as SaO2 of < 94%; < 92%; < 90%; or PaO 2 < 60 mm Hg or < 8 kPa by various authors (7,8,10,12). We defined oxygen desaturation as SpO 2 < 94% as proposed by O'Driscoll et al (7).…”

Effect of maternal oxygen inhalation on foetal free radical activity: a prospective, randomized trial

“…According to this, women undergoing CS under regional anaesthesia should receive supplemental oxygen to provide extra stores of oxygen to prevent intraoperative or post‐natal foetal hypoxia. Previous studies have shown that administration of 35–40% maternal oxygen did not produce sufficient increase in foetal PO 2 and rather exposed women to unnecessary oxygen therapy . On the contrary, oxygen inhalation of 60–100% during elective CS was known to increase arterial oxygen and oxygen free radicals both in mother and the foetus .…”