Evaluation of oxygen administration in cesarean section under spinal anesthesia via lung ultrasound and the oxygen reserve index

Abstract

Background Respiratory functions may be impaired in cesarean section (C/S) delivery performed under spinal anesthesia (SA) and oxygen supplementation may be required. Therefore, we conducted a randomized controlled study aimed to evaluate the effects of different oxygen administrations in pregnant women on the lungs during C/S under SA using ultrasound and oxygen reserve index (ORI). Methods We conducted a randomized, controlled, single-center study from May 1, 2021, to March 31, 2022. A total of 90 patients scheduled for C/S under SA were randomly divided into 3 groups. Following the SA, patients in group 0 were treated with room air, in Group 3 were administered 3 L/min O₂ with a nasal cannula (NC), in Group 6 were administered 6 L/min O₂ with a simple face mask. In addition to routine monitoring, ORI values were measured. Lung aeration was evaluated through the modified lung ultrasound score (LUS) before the procedure (T0), at minute 0 (T1), 20 (T2), and hour 6 (T3) after the procedure, and ∆LUS values were recorded. Results After SA, the ORI values of Group 3 were higher than Group 0 at all times ( p < 0.05), while the intraoperative 1st minute and the 10th, 25th and 40th minutes after delivery ( p = 0.001, p = 0.027, p = 0.001, p = 0.019) was higher than Group 6. When the LUS values of each group were compared with the T0 values a decrease was observed in Group 3 and Group 6 ( p < 0.001, p = 0.016). While ∆LUS values were always higher in Group 3 than in Group 0, they were higher only in T1 and T2 in Group 6. Conclusion We determined that it would be appropriate to prefer 3 L/min supplemental oxygen therapy with NC in C/S to be performed under SA.