Clinical effects of low-dose intravenous ketamine in obstetrics: a systematic review

Abstract

Introduction. Over the past decade, there has been increased attention to ketamine, which is associated with the identification of its new effects when using low (less than 1 mg/kg for bolus administration and less than 20 μg/kg/min for prolonged infusion) doses of the drug. In pregnant women, the pharmacokinetics of most drugs change, so the results of studies of low doses of ketamine obtained in other categories of patients may not be reproduced in the obstetric population. Objectives. Assessment of the clinical effects of various doses and regimens of ketamine administration, within the subanesthetic range, in the perioperative period of cesarean section. Material and Methods. Publications were searched in the electronic databases PubMed, MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials (CENTRAL) by four reviewers independently. The date of the last search query was December 31, 2019. Results. A total of 18 randomized controlled trials (RCTs) involving 2703 patients were included in the review. The results of this systematic review showed that the administration of low doses of ketamine (in the range of 0.15-0.5 mg/kg) in the perioperative period of cesarean section performed under spinal anesthesia can reduce the intensity of pain and the need for analgesics in the postoperative period. The use of low doses of ketamine under these conditions can also be useful to reduce the severity of chills, itching, and the prevention of postoperative nausea and vomiting, post-puncture headache, and postpartum depression. Doses of less than 0.5 mg/kg appear to be safer and comparatively effective in the prevention of the above complications. However, the small number and high heterogeneity of research does not allow us to draw unambiguous conclusions. The effectiveness of low doses of ketamine in the prevention of these complications with general anesthesia also remains unclear. Conclusion. Further research and a meta-analysis of the data are necessary to obtain final conclusions.