Reduction in spinal-induced hypotension with ondansetron in parturients undergoing caesarean section: A double-blind randomised, placebo-controlled study

BACKGROUND:Hypotension remains a frequent complication of spinal anesthesia, increasing the risk of nausea and vomiting, altered mental status, and aspiration. The aim of this systematic review and meta-analysis was to determine whether 5-hydroxytryptamine3 (5-HT3) receptor antagonists, administered

Prevention of Spinal Anesthesia-Induced Hypotension During Cesarean Delivery by 5-Hydroxytryptamine-3 Receptor Antagonists: A Systematic Review and Meta-analysis and Meta-regression.

Background: Side effects of spinal anesthesia are hypotension, bradycardia and shivering. Five-hydroxytriptamine (5-HT), a serotonergic receptor, may be an important factor associated with inducing the Bezold Jarish reflex (BJR) that may lead to the bradycardia and hypotension in the setting of decreased blood volume. Objectives: This study aimed to investigate the effect of intravenous administration of ondansetron, a 5-HT3 receptor antagonist, which could attenuate spinal-induced hypotension, bradycardia and shivering. Patients and Methods: Two hundred and ten patients aged 20-50 years old were scheduled for spinal anesthesia and were divided randomly into three equal groups. The control group received normal saline and intervention groups received 6 mg or 12 mg of intravenous ondansetron 5 minutes before spinal anesthesia. Mean arterial pressure (MAP), heart rate (HR), and shivering were recorded before and after spinal anesthesia every 5 minutes during first 20 minutes of surgery. Results: Demographic data were not statistically different among groups. HR was statistically different between the experimental groups and the control group. Ten patients (14%) in the control group had HR < 50 bpm, that required intravenous atropine compared to experimental groups (P =0.02). In the control group 12 (17%) patients had MAP < 80 mm Hg and required vasopressors compared to experimental groups (P = 0.04). There were no significant differences in MAP and HR between the experimental groups (P =0.06). Incidence of shivering in the control group was 45% (32.70) that was statistically more than experimental groups (P = 0.02). Conclusions: Administration of two different doses of intravenous ondansetron, 6 mg and 12 mg, significantly attenuates spinal induced hypotension, bradycardia and shivering compared to the control saline group. However, the hemodynamic profiles and shivering in experimental groups were not statistically different.

Comparing Two Different Doses of Intravenous Ondansetron With Placebo on Attenuation of Spinal-induced Hypotension and Shivering.

Effects of prophylactic ondansetron on spinal anesthesia-induced hypotension: a meta-analysis

Serotonin (5-HT3) receptor antagonists are commonly used to decrease nausea and vomiting for surgery patients, but these agents may be harmful. We conducted a systematic review on the comparative safety of 5-HT3 receptor antagonists. Searches were done in MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials to identify studies comparing 5-HT3 receptor antagonists with each other, placebo, and/or other antiemetic agents for patients undergoing surgical procedures. Screening search results, data abstraction, and risk of bias assessment were conducted by two reviewers independently. Random-effects pairwise meta-analysis and network meta-analysis (NMA) were conducted. PROSPERO registry number: CRD42013003564. Overall, 120 studies and 27,787 patients were included after screening of 7,608 citations and 1,014 full-text articles. Significantly more patients receiving granisetron plus dexamethasone experienced an arrhythmia relative to placebo (odds ratio (OR) 2.96, 95 % confidence interval (CI) 1.11–7.94), ondansetron (OR 3.23, 95 % CI 1.17–8.95), dolasetron (OR 4.37, 95 % CI 1.51–12.62), tropisetron (OR 3.27, 95 % CI 1.02–10.43), and ondansetron plus dexamethasone (OR 5.75, 95 % CI 1.71–19.34) in a NMA including 31 randomized clinical trials (RCTs) and 6,623 patients of all ages. No statistically significant differences in delirium frequency were observed across all treatment comparisons in a NMA including 18 RCTs and 3,652 patients. Granisetron plus dexamethasone increases the risk of arrhythmia.

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Ewa Morzuch

Papers

Ondansetron Given Intravenously Attenuates Arterial Blood Pressure Drop Due to Spinal Anesthesia: A Double-Blind, Placebo-Controlled Study