Sublingual Glyceryl Trinitrate for Uterine Relaxation at Caesarean Section—a Prospective Trial

Abstract

We report a prospective study on the use of sublingual glyceryl trinitrate at Caesarean section to induce uterine relaxation; 23 women were entered into the study with both emergency and elective cases considered. A metered dose spray was used to deliver a dose of 400 or 800 microgrammes of glyceryl trinitrate to the women. There were no major side-effects of hypotension or postpartum haemorrhage. The mean maximal systolic blood pressure drop in the patients following drug administration was 18% of the systolic pressure prior to drug administration. Subjective assessment of uterine tone showed the uterus to contract well postdelivery in response to standard oxytocic regimens. Minimal maternal side-effects were reported. We conclude that glyceryl trinitrate is a safe form of uterine relaxation at Caesarean section which may be used in emergency situations and may also be given prophylactically in cases such as breech presentation and in delivery of the preterm infant where fetal trauma is possible. The use of a metered-dose sublingual spray is ideally suited to obstetric practice, being both easy to use and also rapidly administered.

Nitroglycerin for Rapid Tocolysis: Development of a Protocol and a Literature Review

“…One patient who received two doses of 50 g of NTG subsequently required a blood transfusion for excessive blood loss in a case complicated by a uterine inversion (Altabef et al 4 ). Postpartum hemorrhage (Craig et al 25 ) and hypotension (Chan et al, 23 Bayhi et al, 3 Mercier et al 6 ) were more commonly observed in parturients receiving initial doses of Ͼ400 g NTG.…”

“…An attractive alternative to i.v. dosing may be the use of the NTG metered dose sublingual spray (Redick and Livingston, 13 Greenspoon and Kovacic, 17 Dalton and Ray, 9 Craig et al, 25 Dawson and Gabbot 26 ).…”

“…We encountered an average of one case appropriate for acute NTG tocolysis for every 1025 live births. Due to the uncommon requirement for acute tocolysis and the complexity of many cases, a 25 Uterine relaxation at cesarean delivery for various indications: repeat, fail forceps, breech, distress, macrosomia, obstructed labor 23 400 g spray, up to two doses Not noted One postpartum hemorrhage of 800 ml (hemoglobin drop from 12.3 to 8.6 dl); systolic fall ranged from 0% to 46%; no other significant symptoms Dalton and Ray 9 Entrapped second twin 1 400 g spray, up to three doses 45 sec None; Apgar scores of second twin were 9 and 9 Dawson and Gabbot 26 Complete uterine inversion 1 1% isofluorine; 800 g spray, up to two doses; 1 liter Hartmann's i.v. and 500 ml colloid before administration 30 sec Severe hypotension (65/30 mm Hg) corrected with additional 500 ml Gelofusine, 20 mg methozamine, 200 g phenylephrine Dessard et al 10 Difficult delivery following fetal death 1 150 g i.v.…”

Glyceryl Trinitrate and Acute Uterine Relaxation: A Literature Review

“…In two studies, a total of 89 patients received GTN during elective caesarean section as a means of achieving uterine relaxation 6,7 . Maternal and fetal effects were also evaluated.…”

“…The uterus is a smooth muscle organ and nitro-vasodilators such as amyl nitrate have been used to achieve rapid uterine relaxation for over a century [1][2][3] . The use of GTN to achieve rapid uterine relaxation during obstetric emergencies has generated many observational studies [4][5][6][7][8][9][10][11][12][13][14][15][16] and case reports [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] in the anaesthetic and obstetric literature. The ability to achieve simple, reliable and rapid uterine relaxation is of particular interest to the anaesthetist, as this would lessen the need to subject the parturient to the risks of anaesthesia.…”