Nitrous Oxide Effect on Relieving Anxiety and Pain in Parturients Under Spinal Anesthesia for Caesarean Section

Abstract

Background:Anxiety is an unpleasant experience that may have adverse effects on the process of anesthesia, cesarean delivery, recovery period and postoperative pain. Anxiety can also affect maternal satisfaction of the medical cares that provided by the medical team.Objectives:To compare the effects of inhalational 50% nitrous oxide (N2O) with oxygen on reducing anxiety and pain in parturients who have undergone caesarean section under spinal anesthesia.Patients and Methods:In this double-blind clinical trial, 56 primigravid parturients were randomly assigned into two groups according to the operating list schedule. The experimental group received inhalational 50% N2O three minutes before spinal anesthesia to the end of delivery. The control group received only oxygen. Flow meters were covered by a dark shield and monitored by an experienced nurse anesthetist. Pain and anxiety of patients were measured using visual analogue scale (VAS) by another nurse who was neither involved in the anesthetic process nor aware of the participants' allocation and inhalation agents. Data regarding sedation level, ephedrine use, nausea, vomiting, and neonate Apgar score were recorded as well.Results:Overall mean ± SD of anxiety VAS scores was 1.77 ± 1.5 in the experimental group and 3.12 ± 1.73 in the control groups (P = 0.003). The mean ± SD of pain VAS scores of the experimental and control groups were 0.82 ± 1.5 and 1.64 ± 1.45, respectively (P = 0.042). No significant differences were seen regarding blood oxygen saturation, neonate Apgar scores, total used ephedrine, operation time, delivery time, nausea, and vomiting between the two studied groups.Conclusions:Inhalation of 50% N2O can significantly decrease anxiety (without clinically significant side effects) compared with O2 inhalation in parturients who have undergone caesarean section under spinal anesthesia.

A Randomized Controlled Trial Comparing Use of Enthonox With Pethidine for Pain Relief in Primigravid Women During the Active Phase of Labor

“…Nitrous oxide is usually run through a mouth mask intermittently, starting about 30 seconds before each contraction (7, 8). Inhalation of 50% nitrous oxide can significantly decrease anxiety without clinically significant side effects, and its effects are quickly reversible upon discontinuation of inhalation (8, 9). …”

“…Pethidine or meperidine hydrochloride was the first synthetic opioid, synthesized in 1932 (9). Systemic pethidine is routinely used throughout the UK for labor analgesia (10, 11).…”

Association between preoperative maternal anxiety and neonatal outcomes: a prospective observational study

“…Thus, reducing maternal anxiety with midazolam does not change the newborn outcome as compared with the no treatment group. Similarly, inhalation of 50% N 2 O can significantly decrease anxiety level in patients undergoing cesarean delivery; however, no significant difference occurs between Apgar scores at the first and fifth minute compared with O 2 inhalation [20]. Preoperative anxiety can have an effect on intraoperative hemodynamic responses.…”

Managing pain and anxiety during transabdominal chorionic villus sampling. A noninferiority randomized trial of nitrous oxide vs local anesthesia

“…4 To date, no randomized trial has evaluated pain reduction in CVS. 20 The use of N 2 O for labor analgesia and anxiolysis is less common in the USA but has gained increasing interest since N 2 O was approved by the Food and Drug Administration (FDA) 16,21 and health authorities in Europe. 11 A survey conducted in the UK showed that 89% of operators reported the use of local anesthesia for CVS.…”

“…Moreover, N 2 O presents a major advantage of inducing a temporary and reversible hazy memory effect confined to the memories of procedure-related trauma 19,21,29. Moreover, several studies indicate that N 2 O use during labor effectively helps women relax and reduces their perception of pain, even though they may still be aware that pain is present.…”