Relative potency of norepinephrine and mephentermine bolus for the treatment of spinal hypotension during elective caesarean delivery – a randomized, blinded up-down sequential allocation study
M. Mohta, R. Kumar, R. Salhotra, S. Kumari, P. Mulodhia
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引用次数: 0
Abstract
Background
Vasopressors are the mainstay of management of spinal hypotension during caesarean delivery. Norepinephrine, an α- and β-adrenergic agonist, has a lower incidence of bradycardia and is an alternative to phenylephrine. Mephentermine is another such vasopressor and is used in many developing countries. Earlier studies compared norepinephrine and mephentermine using fixed or indirectly calculated doses. The purpose of the current study was to estimate their equipotent doses for the treatment of hypotension.
Methods
One hundred healthy parturients with term, uncomplicated, singleton pregnancy undergoing elective caesarean delivery, who developed spinal hypotension, were studied. Hypotension was defined as >20% fall from baseline systolic blood pressure and was treated with a blinded, predetermined dose of norepinephrine or mephentermine. The dose for each patient was determined according to the response in the previous patient using the Narayana rule for up-down sequential allocation. The ED95 and ED50 of norepinephrine and mephentermine boluses and their relative potency ratio were calculated.
Results
The ED95 was 7.2 µg (95% confidence interval [CI]: 4.9 to 9.5) for norepinephrine and 1.59 mg (95% CI: 1.43 to 1.75) for mephentermine. The ED50 values were 6.9 µg (95% CI: 6.2 to 7.7) and 1.39 mg (95% CI: 1.33 to 1.46), respectively. The relative ED95 and ED50 potency ratios of norepinephrine to mephentermine were 222 (95% CI: 201 to 242) and 201 (95% CI: 193 to 210), respectively.
Conclusion
When used as bolus for treatment of spinal hypotension during elective caesarean delivery, norepinephrine is approximately 220 times more potent than mephentermine; therefore, norepinephrine 8 μg is approximately equivalent to mephentermine 1.7 mg.
期刊介绍:
The International Journal of Obstetric Anesthesia is the only journal publishing original articles devoted exclusively to obstetric anesthesia and bringing together all three of its principal components; anesthesia care for operative delivery and the perioperative period, pain relief in labour and care of the critically ill obstetric patient.
• Original research (both clinical and laboratory), short reports and case reports will be considered.
• The journal also publishes invited review articles and debates on topical and controversial subjects in the area of obstetric anesthesia.
• Articles on related topics such as perinatal physiology and pharmacology and all subjects of importance to obstetric anaesthetists/anesthesiologists are also welcome.
The journal is peer-reviewed by international experts. Scholarship is stressed to include the focus on discovery, application of knowledge across fields, and informing the medical community. Through the peer-review process, we hope to attest to the quality of scholarships and guide the Journal to extend and transform knowledge in this important and expanding area.