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A Prospective, Randomized, Double-Blinded Study of the Effect of Intravenous Ondansetron on the Effective Dose in 50% of Subjects of Prophylactic Phenylephrine Infusions for Preventing Spinal Anesthesia-Induced Hypotension During Cesarean Delivery.
Anesth Analg. 2020 08; 131(2):564-569.A&A

Abstract

BACKGROUND

Ondansetron has been shown to reduce the incidence of hypotension and vasopressor requirement during spinal anesthesia for obstetric and nonobstetric surgery. However, the magnitude of this effect has not been fully quantified. In this parallel-group, randomized, double-blinded study, we determined the effective dose in 50% of subjects (ED50) of a prophylactic phenylephrine infusion for preventing hypotension in patients who received a single dose of intravenous ondansetron 4 mg or saline control before combined spinal-epidural anesthesia for elective cesarean delivery. ED50 values obtained were compared to estimate the effect of ondansetron versus placebo on vasopressor requirement.

METHODS

Sixty parturients were randomly assigned to receive ondansetron (group O) or saline control (group C) 10 minutes before positioning for induction of spinal anesthesia. A prophylactic phenylephrine infusion was used to prevent hypotension. The first patient in each group received a phenylephrine infusion at the rate of 0.5 µg/kg/min. The infusion rate for each subsequent patient was varied with increments or decrements of 0.05 µg/kg/min based on the response of the previous patient, and the effective dose of the phenylephrine infusion for preventing hypotension in 50% of patients (ED50) was calculated for each group and compared using up-down sequential analysis. Probit regression was applied as a backup and sensitivity analysis was used to compare ED50 values for phenylephrine between groups by comparing calculated relative mean potency.

RESULTS

The ED50 (mean [95% confidence interval (CI)]) of the rate of phenylephrine infusion was lower in group O (0.24 µg/kg/min [0.10-0.38 µg/kg/min]) compared with group C (0.32 µg/kg/min [0.14-0.47 µg/kg/min]) (P < .001). The total consumption of phenylephrine (mean ± standard deviation [SD]) until delivery was lower in group O (316.5 ± 25.9 µg) than in group C (387.7 ± 14.7 µg, P = .02). The estimate of relative median potency for phenylephrine for group O versus group C was 0.74 (95% CI, 0.37-0.95).

CONCLUSIONS

Under the conditions of this study, intravenous ondansetron 4 mg reduced the ED50 of a prophylactic phenylephrine infusion by approximately 26% in patients undergoing cesarean delivery under combined spinal-epidural anesthesia.

Authors+Show Affiliations

From the Department of Anesthesia, Jiaxing University Affiliated Women and Children Hospital, Jiaxing City, China.From the Department of Anesthesia, Jiaxing University Affiliated Women and Children Hospital, Jiaxing City, China. Department of Anesthesia, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China.From the Department of Anesthesia, Jiaxing University Affiliated Women and Children Hospital, Jiaxing City, China.From the Department of Anesthesia, Jiaxing University Affiliated Women and Children Hospital, Jiaxing City, China.Department of Obstetrics, Jiaxing University Affiliated Women and Children Hospital, Jiaxing City, China.Department of Obstetrics, Jiaxing University Affiliated Women and Children Hospital, Jiaxing City, China.Department of Anesthesiology, Sidra Medicine, Doha, Qatar.Department of Anesthesia, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China.

Pub Type(s)

Journal Article
Randomized Controlled Trial
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

31725021

Citation

Xiao, Fei, et al. "A Prospective, Randomized, Double-Blinded Study of the Effect of Intravenous Ondansetron On the Effective Dose in 50% of Subjects of Prophylactic Phenylephrine Infusions for Preventing Spinal Anesthesia-Induced Hypotension During Cesarean Delivery." Anesthesia and Analgesia, vol. 131, no. 2, 2020, pp. 564-569.
Xiao F, Wei C, Chang X, et al. A Prospective, Randomized, Double-Blinded Study of the Effect of Intravenous Ondansetron on the Effective Dose in 50% of Subjects of Prophylactic Phenylephrine Infusions for Preventing Spinal Anesthesia-Induced Hypotension During Cesarean Delivery. Anesth Analg. 2020;131(2):564-569.
Xiao, F., Wei, C., Chang, X., Zhang, Y., Xue, L., Shen, H., Ngan Kee, W. D., & Chen, X. (2020). A Prospective, Randomized, Double-Blinded Study of the Effect of Intravenous Ondansetron on the Effective Dose in 50% of Subjects of Prophylactic Phenylephrine Infusions for Preventing Spinal Anesthesia-Induced Hypotension During Cesarean Delivery. Anesthesia and Analgesia, 131(2), 564-569. https://doi.org/10.1213/ANE.0000000000004534
Xiao F, et al. A Prospective, Randomized, Double-Blinded Study of the Effect of Intravenous Ondansetron On the Effective Dose in 50% of Subjects of Prophylactic Phenylephrine Infusions for Preventing Spinal Anesthesia-Induced Hypotension During Cesarean Delivery. Anesth Analg. 2020;131(2):564-569. PubMed PMID: 31725021.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A Prospective, Randomized, Double-Blinded Study of the Effect of Intravenous Ondansetron on the Effective Dose in 50% of Subjects of Prophylactic Phenylephrine Infusions for Preventing Spinal Anesthesia-Induced Hypotension During Cesarean Delivery. AU - Xiao,Fei, AU - Wei,Changna, AU - Chang,Xiangyang, AU - Zhang,Yinfa, AU - Xue,Lili, AU - Shen,Huaxiang, AU - Ngan Kee,Warwick D, AU - Chen,Xinzhong, PY - 2019/11/15/pubmed PY - 2020/9/4/medline PY - 2019/11/15/entrez SP - 564 EP - 569 JF - Anesthesia and analgesia JO - Anesth Analg VL - 131 IS - 2 N2 - BACKGROUND: Ondansetron has been shown to reduce the incidence of hypotension and vasopressor requirement during spinal anesthesia for obstetric and nonobstetric surgery. However, the magnitude of this effect has not been fully quantified. In this parallel-group, randomized, double-blinded study, we determined the effective dose in 50% of subjects (ED50) of a prophylactic phenylephrine infusion for preventing hypotension in patients who received a single dose of intravenous ondansetron 4 mg or saline control before combined spinal-epidural anesthesia for elective cesarean delivery. ED50 values obtained were compared to estimate the effect of ondansetron versus placebo on vasopressor requirement. METHODS: Sixty parturients were randomly assigned to receive ondansetron (group O) or saline control (group C) 10 minutes before positioning for induction of spinal anesthesia. A prophylactic phenylephrine infusion was used to prevent hypotension. The first patient in each group received a phenylephrine infusion at the rate of 0.5 µg/kg/min. The infusion rate for each subsequent patient was varied with increments or decrements of 0.05 µg/kg/min based on the response of the previous patient, and the effective dose of the phenylephrine infusion for preventing hypotension in 50% of patients (ED50) was calculated for each group and compared using up-down sequential analysis. Probit regression was applied as a backup and sensitivity analysis was used to compare ED50 values for phenylephrine between groups by comparing calculated relative mean potency. RESULTS: The ED50 (mean [95% confidence interval (CI)]) of the rate of phenylephrine infusion was lower in group O (0.24 µg/kg/min [0.10-0.38 µg/kg/min]) compared with group C (0.32 µg/kg/min [0.14-0.47 µg/kg/min]) (P < .001). The total consumption of phenylephrine (mean ± standard deviation [SD]) until delivery was lower in group O (316.5 ± 25.9 µg) than in group C (387.7 ± 14.7 µg, P = .02). The estimate of relative median potency for phenylephrine for group O versus group C was 0.74 (95% CI, 0.37-0.95). CONCLUSIONS: Under the conditions of this study, intravenous ondansetron 4 mg reduced the ED50 of a prophylactic phenylephrine infusion by approximately 26% in patients undergoing cesarean delivery under combined spinal-epidural anesthesia. SN - 1526-7598 UR - https://www.unboundmedicine.com/medline/citation/31725021/A_Prospective_Randomized_Double_Blinded_Study_of_the_Effect_of_Intravenous_Ondansetron_on_the_Effective_Dose_in_50_of_Subjects_of_Prophylactic_Phenylephrine_Infusions_for_Preventing_Spinal_Anesthesia_Induced_Hypotension_During_Cesarean_Delivery_ L2 - https://doi.org/10.1213/ANE.0000000000004534 DB - PRIME DP - Unbound Medicine ER -