Association between preoperative anxiety and hypotension during spinal anaesthesia In Women undergoing elective caesarean delivery

Abstract

Background Spinal anaesthesia is the most popular form of regional anaesthesia used for Caesarean delivery in the world today; approximately 78% of women having a Caesarean section will receive regional anaesthesia (spinal or epidural). Hypotension is the most common complication associated with spinal anaesthesia, occurring in up to 64% of cases1. Hypotension after spinal anaesthesia depends on many factors, including dose of local anaesthetic, patient positioning, height of patient, fluid preloading and co-loading. Neonates born by Caesarean delivery under spinal anaesthesia are more acidaemic compared with those delivered under either epidural or general anaesthesia2-4. The principal mechanism by which spinal anaesthesia causes maternal hypotension is the blockade of sympathetic efferent neurons. Anxiety is known to cause generalized sympathetic activation prior to elective surgery in most patients. Patients with higher baseline sympathetic activation have been shown to have more marked hypotension after spinal anaesthesia5. Together, these findings provided a rational basis for the hypothesis that patients with higher preoperative anxiety would experience more marked hypotension after the induction of spinal anaesthesia. No studies have been done to assess preoperative anxiety on the development of hypotension after neuraxial anaesthesia at The Kenyatta National Hospital. Objective This study aimed to determine the association between preoperative anxiety and arterial blood pressure changes during spinal anaesthesia for elective Caesarean delivery at the Kenyatta National Hospital. Research Methodology This was a prospective observational study to assess the effect of preoperative anxiety on arterial blood pressure changes during spinal anaesthesia for caesarean delivery at the Kenyatta National Hospital maternity theatres. Study population The study population was all patients scheduled for elective caesarean delivery at The Kenyatta National labour ward. Sample size The sample size was determined by the Cochran (1963:75) formula to yield a representative sample of 100.08 Results This study showed that the incidence of hypotension in elective caesarean section was much lower than in previous studies. Hypotension occurred in only 26(23.2%) of the respondents. In this study patients were subjected to an S-Anxiety scale a day before surgery to evaluate how the respondents felt at that moment, majority 69(61.6%) of the patients were severely anxious. However according to VAS score on the day of surgery majority 66(58.9%) of the patients were moderately anxious and only 4(3.6%) were severely anxious. This comparison was attributed to high numbers of postponement or cancellation of elective caesarean sections due to overwhelming emergencies in maternity theatres, patients remained anxious in the ward, starved and awaiting indefinitely for surgery and were relieved of anxiety when taken to theatre. This study showed that majority of the patients were contented with capabilities of the facility and minorityof the patients were actually unaware of the mode of anaesthesia to be administered. The results of this study showed that 28(25.26%) of the respondents were aged between 32 and 34 years, and 43(38.4%) of the respondents had a parity of 1 + 0. The most common indication of caesarean section was one previous scar 55(49.1%). Majority (72.7%) of the patients who had hypotension were severely anxious. Majority (57.7%) of the patients who did not have hypotension were severely anxious. Likelihood Ratio Chi-square test (p-value = .302) indicated that there was insignificant association between anxiety levels and presence of hypotension The study supports the null hypothesis that the level of preoperative anxiety is not associated with the occurrence of hypotension during spinal anaesthesia for caesarean delivery and more than one factor are infact attributed to occurrence of hypotension.