Effective Dose of Prophylactic Oxytocin Infusion During Cesarean Delivery in 90% Population of Nonlaboring Patients With Preeclampsia Receiving Magnesium Sulfate Therapy and Normotensives: An Up-Down Sequential Allocation Dose-Response Study.
Anesth Analg
; 134(2): 303-311, 2022 02 01.
Article
in English
| MEDLINE | ID: covidwho-1928240
ABSTRACT
BACKGROUND:
Oxytocin administration during cesarean delivery is the first-line therapy for the prevention of uterine atony. Patients with preeclampsia may receive magnesium sulfate, a drug with known tocolytic effects, for seizure prophylaxis. However, no study has evaluated the minimum effective dose of oxytocin during cesarean delivery in women with preeclampsia.METHODS:
This study compared the effective dose in 90% population (ED90) of oxytocin infusion for achieving satisfactory uterine tone during cesarean delivery in nonlaboring patients with preeclampsia who were receiving magnesium sulfate treatment with a control group of normotensives who were not receiving magnesium sulfate. This prospective dual-arm dose-finding study was based on a 91 biased sequential allocation design. Oxytocin infusion was initiated at 13 IU/h, on clamping of the umbilical cord, in the first patient of each group. Uterine tone was graded as satisfactory or unsatisfactory by the obstetrician at 4 minutes after initiation of oxytocin infusion. The dose of oxytocin infusion for subsequent patients was decided according to the response exhibited by the previous patient in the group; it was increased by 2 IU/h after unsatisfactory response or decreased by 2 IU/h or maintained at the same level after satisfactory response, in a ratio of 19. Oxytocin-associated side effects were also evaluated. Dose-response data for the groups were evaluated using a log-logistic function and ED90 estimates were derived from fitted equations using the delta method.RESULTS:
The ED90 of oxytocin was significantly greater for the preeclampsia group (n = 27) than for the normotensive group (n = 40) (24.9 IU/h [95% confidence interval {CI}, 22.4-27.5] and 13.9 IU/h [95% CI, 12.4-15.5], respectively); the difference in dose requirement was 10.9 IU/h (95% CI, 7.9-14.0; P < .001). The number of patients with oxytocin-related hypotension, defined as a decrease in systolic blood pressure >20% from baseline or to <90 mm Hg, was significantly greater in the preeclampsia group (92.6% vs 62.5%; P = .030), while other side effects such as ST-T depression, nausea/vomiting, headache, and flushing, were not significantly different. There was no significant difference in the need for additional uterotonic or uterine massage, estimated blood loss, and need for re-exploration for uncontrolled bleeding.CONCLUSIONS:
Patients with preeclampsia receiving preoperative magnesium therapy need a greater intraoperative dose of oxytocin to achieve satisfactory contraction of the uterus after fetal delivery, as compared to normotensives.
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Pre-Eclampsia
/
Oxytocin
/
Cesarean Section
/
Pre-Exposure Prophylaxis
/
Analgesics
/
Magnesium Sulfate
Type of study:
Cohort study
/
Diagnostic study
/
Experimental Studies
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Observational study
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Prognostic study
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Randomized controlled trials
Limits:
Adult
/
Female
/
Humans
/
Pregnancy
/
Young adult
Language:
English
Journal:
Anesth Analg
Year:
2022
Document Type:
Article
Affiliation country:
Ane.0000000000005701
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