Optimal Dose of Pituitrin in Laparoscopic Uterine Myomectomy: A Double-Blinded, Randomized Controlled Trial

Optimizing nicardipine dosage for effective control of pituitrin-induced hypertension in laparoscopic myomectomy undergoing total intravenous anesthesia

BACKGROUND

This study aimed to determine the median effective dose (ED50) and 95% effective dose (ED95) of nicardipine for treating pituitrin-induced hypertension during laparoscopic myomectomy, providing guidance for the management of intraoperative blood pressure in such patients.

METHODS

Among the initial 40 participants assessed, 24 underwent elective laparoscopic myomectomy. A sequential up-and-down method was employed to ascertain the ED50 of nicardipine based on its antihypertensive efficacy. Nicardipine was initially administered at 6 µg/kg following the diagnosis of pituitrin-induced hypertension in the first patient. Dosing adjustments were made to achieve the desired antihypertensive effect, restoring systolic blood pressure and heart rate to within ± 20% of baseline within 120 s. The dosing increment or reduction was set at 0.5 µg/kg for effective or ineffective responses, respectively. The ED50 and ED95 of nicardipine were calculated using Probit regression by Maximum Likelihood Estimation (MLE) to establish dose-response curves and confidence intervals.

RESULTS

24 patients were included for analysis finally. The ED50 and ED95 of nicardipine for blood pressure control after pituitrin injection were determined. The study found that the ED50 of nicardipine for treating pituitrin-induced hypertension was 4.839 µg/kg (95% CI: 4.569-5.099 µg/kg), and the ED95 was estimated at 5.308 µg/kg (95% CI: 5.065-6.496 µg/kg). Nicardipine effectively mitigated the hypertensive response caused by pituitrin without inducing significant tachycardia or hypotension.

CONCLUSIONS

Nicardipine effectively controlled blood pressure after pituitrin injection during laparoscopic myomectomy, with ED50 and ED95 values established. This research highlights the potential utility of nicardipine in addressing hypertensive responses induced by pituitrin, particularly in clinical settings where pituitrin is routinely administered.

Dose-response study of prophylactic nitroglycerin for prevention of pituitrin-induced hypertension during laparoscopic myomectomy: a prospective, randomized study

Objective

To determine the dose-response of nitroglycerin in preventing pituitrin-induced hypertension in patients undergoing laparoscopic myomectomy.

Methods

Hundred patients scheduled for elective laparoscopic myomectomy were randomly allocated into one of five groups (n = 20) to receive intravenous bolus of prophylactic nitroglycerin at 0, 50, 75, 100, and 125 μg one minute following administration of 3 IU of pituitrin into the myometrium. The patients were monitored for pituitrin-induced hypertension with the primary outcome to determine the effective dose of prophylactic nitroglycerin, defined as complete prevention of pituitrin-induced hypertension during the study period. Probit analysis was used to calculate the median effective dose (ED₅₀) and 95% effective dose (ED₉₅) of prophylactic nitroglycerin.

Results

Hypertension occurred in 19/20, 10/20, 8/20, 2/20, and 1/20 in patients who received 0, 50, 75, 100, and 125 ug of prophylactic nitroglycerin, respectively. The calculated ED₅₀ and ED₉₅ of nitroglycerin for preventing hypertension were 54 μg (95%CI: 35~66 μg) and 136 μg (95%CI: 105~289 μg).

Conclusion

A prophylactic bolus of nitroglycerin administered immediately following injection of pituitrin into the myometrium during laparoscopic myomectomy effectively prevented pituitrin-induced hypertension, with the ED₅₀ and ED₉₅ of 54 μg and 136 μg, respectively. This information would be useful for clinical practice.

Clinical trial registration

www.chictr.org.cn, Identifier ChiCTR2200062282.