A Potent Uterine Relaxant for Internal Podalic Version: Case
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Arch Gynecol Obstet (2009) 280:873–875 DOI 10.1007/s00404-009-1077-1 LETTER TO THE EDITOR Intravenous nitroglycerin: a potent uterine relaxant for internal podalic version: case Manju N. Gandhi · Niraj N. Mahajan · Hemlata R. Iyer · Sneha D. Shirodkar Received: 8 January 2009 / Accepted: 26 March 2009 / Published online: 9 April 2009 © Springer-Verlag 2009 Dear Editor, performed under spinal anesthesia: two cases of intrapar- The uterine-muscle relaxation required for complicated tum external cephalic version, internal intrapartum podalic obstetric situations traditionally has been achieved by use of a version of the second twin, and for the fetal head entrap- potent inhalation anesthetic. However, this procedure exposes ment during vaginal breech delivery [1]. We report a case the obstetric patient with full stomach to unnecessary general of IPV of intrauterine fetal demise (IUFD) in which relaxa- anesthesia, with the attendant risk and potentially lethal com- tion of the uterus was accomplished quickly and safely with plications. Emergent uterine relaxation may be required for the use of IV nitroglycerin. conditions such as retained placenta, uterine inversion, inter- A 30-year-old gravida 4 para 3 at 38 weeks gestation nal podalic version (IPV), and breech extraction. presented in active labor with antepartum hemorrhage since EVective on smooth muscle tissue and a venodilator, 2 h. Ultrasound conWrmed transverse lie, abruption placen- nitroglycerin is a short-acting and a potent uterine relaxant tae and IUFD; and examination revealed 4 cm dilated cer- [1, 2]. Safety, predictability, and ease of intravenous (IV) vix. Her vitals were stable, hematocrit was 28% and administration of this drug have been established, and it has coagulation proWle was normal. She made good progress, attracted the attention of obstetricians. Nitroglycerin is pri- reaching 8 cm cervical dilatation over the next 4 h after marily indicated for the treatment or prevention of angina which she started having hematuria so the decision was pectoris. Nitroglycerin has been used during manual extrac- taken immediately to deliver the fetus by IPV. tion of retained placenta without clinically signiWcant Uterine relaxation was achieved by direct IV nitroglyc- hemodynamic eVects [1] and during replacement of a con- erin bolus 50 mcg along with ketamine hydrochloride tracted, completely prolapsed uterus [1, 2]. Its use as a 30 mg IV for sedation. Infusion of nitroglycerin at the rate tocolytic has been reported in cesarean delivery of twins of 50 mcg/min was started after 1 min of loading dose. When the uterus was relaxed (conWrmed with manual pal- pation), approximately 45 s after bolus, the obstetrician per- formed IPV and breech extraction. The procedure was completed in 4 min and 30 s. The total dose of nitroglycerin M. N. Gandhi · H. R. Iyer was 250 mcg. The placenta delivered spontaneously with Department of Anaesthesiology, B. Y. L. Nair Charitable Hospital, T. N. Medical College, Dr. A. L. Nair road, Bombay 400008, no unusual cord traction. Transabdominal massage of the Maharashtra, India uterus and oxytocin infusion improved uterine tone. The hematocrit had decreased from 28 to 22%. One unit blood N. N. Mahajan · S. D. Shirodkar transfusion was given and she remained stable in the post- Department of Obstetrics and Gynaecology, B. Y. L. Nair Charitable Hospital, T. N. Medical College, partum period. Hematuria was cleared in 2 h postpartum. Dr. A. L. Nair road, Bombay 400008, Maharashtra, India Monitoring consisted of electrocardiogram, SpO2 and non-invasive blood pressure measurement. Hypotension N. N. Mahajan (&) occurred 1 min after nitroglycerin injection, which was nor- 31, Dhaqnvantri Nagar, Sevagram, Wardha 442102, Maharashtra, India malized within 50 s with rapid infusion of crystalloids. The e-mail: [email protected] heart rate increased at the same time to 130 bpm. Side 123 874 Arch Gynecol Obstet (2009) 280:873–875 eVects such as headache and prolonged uterine relaxation may explain why acute administration of nitroglycerin is not were not observed. universally associated with clinically signiWcant hypotension. This case demonstrates the value of small-dose intrave- Side eVects such as headache, prolonged uterine relaxation, nous nitroglycerin, in combination with ketamine hydro- and palpitation were not noted. chloride, for IPV. During obstetric emergencies in vaginal Amyl nitrate is another smooth muscle relaxant, must and cesarean deliveries, there is often a need for rapid and be inhaled, and adverse reactions, particularly orthostatic transient relaxation of the cervix and uterus to allow obstet- hypotension, tachycardia, and a severe throbbing head- ric maneuvres [1]. Uterine relaxation is usually induced by ache are common. The major advantages of nitroglycerin rapid induction of general anesthesia with halogenated over amyl nitrate are those of convenience and accuracy inhalation agents. General anesthesia subjects the parturi- in delivery. Tocolytic agents such as magnesium sulfate ents with full stomachs to the risk of aspiration and and terbutaline have also been used to obtain uterine hypoxia. The concentration of inhalation drug necessary to relaxation. The slower onset of action and the potentially relax the refractory uterus might depress the cardiovascular dangerous side eVects (such as cardiac dysrhythmias and system at a time when hemodynamics is unstable. Keta- hypotension) make their use less desirable. Another mine hydrochloride used in our case is suYcient to sup- advantage of nitroglycerin over these drugs is faster press pain caused by IPV; however, used alone, it does not elimination. Therefore, once the acute problem requiring achieve the uterine relaxation required for the maneuver. uterine relaxation is over, the uterus will contract Because safety, predictability, and ease of administration of adequately. IV nitroglycerin has been Wrmly documented [1], we have In summary, this outcome adds to the mounting evi- used this drug in combination with ketamine hydrochloride dence of the safety and eYcacy of IV-NTG where rapid as sedative and analgesic. Many authors used epidural anal- uterine relaxation is needed. However, data are lacking that gesia instead for IPV [1, 3, 4]. conclusively demonstrate its superiority over other methods In the literature review by Riley et al. [5], they found in any of these settings. Further laboratory and controlled nine reports documenting a total of more than 50 cases clinical studies are needed to determine the eYcacy of where intravenous or sublingual nitroglycerin had been nitroglycerin in obstetric practice. used for uterine relaxation in obstetric emergencies. In most instances the indication for using nitroglycerin was a ConXict of interest statement None. retained placenta (40 cases). In Wve cases there were prob- lems associated with twin deliveries: one case of head References entrapment of the Wrst twin due to poor uterine relaxation at cesarean section, three for IPV, and one for external cepha- 1. Vinatier D, Dufour P, Bérard J (1996) Utilization of intravenous lic version of the second twin. In two other cases, success- nitroglycerin for obstetrical emergencies. Int J Gynaecol Obstet ful correction of uterine inversion was obtained after 55:129–134. doi:10.1016/S0020-7292(96)02754-3 adequate uterine relaxation with IV nitroglycerin. 2. Dayan SS, Schwalbe SS (1996) The use of small-dose intravenous Doses ranging from 50 to 1,000 mcg have been used and nitroglycerin in a case of uterine inversion. Anesth Analg V 82:1091–1093. doi:10.1097/00000539-199605000-00041 found to be e ective and safe [1, 6, 7]. In our case only 3. Dufour P, Vinatier D, Vanderstichèle S et al (1996) Intravenous 250 mcg nitroglycerin was required. The speed with which nitroglycerin for intrapartum internal podalic version of the second uterine relaxation occurred as well as the ease with which non-vertex twin. Eur J Obstet Gynecol Reprod Biol 70:29–32. IPV was carried was impressive when compared with our doi:10.1016/S0301-2115(96)02537-7 4. Dufour P, Vinatier D, Vanderstichele S, Ducloy AS, Depret S, past experiences using volatile anesthetic agents. Also time Monnier JC (1998) Intravenous nitroglycerin for internal podalic reported by several authors [1, 2, 8] for uterine relaxation version of the second twin in transverse lie. Obstet Gynecol was 30–90 seconds which is similar to our case. 92:416–419. doi:10.1016/S0029-7844(98)00231-2 In our case only mild hypotension was noted and it 5. Riley ET, Flanagan B, Cohen SE, Chitkarat U (1996) Intravenous nitroglycerin: a potent uterine relaxant for emergency obstetric seemed clinically unimportant. Concerns about the risk of procedures. Review of literature and report of three cases. Int hypotension following nitroglycerin administration in the J Obstet Anesth 5:264–268. doi:10.1016/S0959-289X(96)80048-3 obstetric setting have so far been unfounded. Several reports 6. Chan AS, Ananthanarayan C, Rolbin SH (1995) Alternating [8–10] suggest that there may be a measurable decrease in nitroglycerin and syntocinon to facilitate uterine exploration and removal of an adherent placenta. Can J Anaesth 42:335– blood pressure after administration of IV nitroglycerin, but it 337 has not been considered clinically signiWcant. Interestingly, 7. Lowenwirt IP, Zauk RM, Handwerker SM (1997) Safety of intra- the vascular eVects of nitroglycerin act predominantly on the venous glyceryl trinitrate in management of retained placenta. venous circulation, where it produces an increase in venous Aust N Z J Obstet Gynaecol 37:20–24. doi:10.1111/j.1479- 828X.1997.tb02212.x capacitance, a fall in venous return and hence a decrease in 8. Peng AT, Gorman RS, Shulman SM, DeMarchis E, Nyunt K, myocardial work. This predilection for the venous circulation Blancato LS (1989) Intravenous nitroglycerin for uterine relaxation 123 Arch Gynecol Obstet (2009) 280:873–875 875 in the postpartum patient with retained placenta. Anesthesiology 10. Greenspoon JS, Kovacic A (1991) Breech extraction facilitated 71:172–173. doi:10.1097/00000542-198907000-00039 by glyceryl trinitrate sublingual spray. Lancet 338:124–125.