Intraoperative anaphylaxis to ranitidine during cesarean section
A 25-year-old, 55-kg ASA-1 primigravida with no past history of drug allergy was posted for the emergency cesarean section for oligohydramnios. The patient was connected to monitors and co-loaded with 500 ml of lactated ringer solution, while 1.8 ml of hyperbaric bupivacaine was administered using a 25G spinal needle to achieve a sensory block level of T6. After baby delivery, 10U oxytocin was added to the IV fluids and the patient was sedated with Inj. midazolam 1 mg and Inj. pethidine 25 mg. As the uterus was atonic, Inj. methylergometrine 0.2 U was given intravenously slowly. After 5 min, 50 mg ranitidine hydrochloride was given intravenously. Immediately, the patient became restless, complaining of itching in upper limbs, face, and chest. She appeared flushed and was coughing. 100% oxygen was administered with face mask, with closed circuit, and the tidal volume was found to be adequate. Auscultation showed the presence of mild bilateral wheeze. We suspected an allergic reaction and as the patient was hemodynamically stable, Inj. pheneramine maleate 50 mg, Inj. hydrocortisone 100 mg, and Inj. deriphylline 220 mg (etofylline and theophylline hydrate) were given intravenously immediately. Within minutes, peripheral pulses became feeble, the heart rate increased from 68 to 130/min, consciousness deteriorated, and respiration was inadequate and non-invasive blood pressure was showing cuff error.\nA probable diagnosis of anaphylactic shock was made and Inj. adrenaline 1 ml of 1:10,000 was given intravenously and 500 ml lactated ringer solution was rushed. Simultaneously, intubation was accomplished with 7.0 mm ID cuffed oral ETT, after administering Inj. midazolam 2 mg, Inj. fentanyl 40 mcg. and Inj. succinylcholine 75 mg. With a second bolus of Inj adrenaline, peripheral pulses began to improve and blood pressure recorded as 80/61 mmHg. Second intravenous access was secured and Inj. adrenaline infusion 0.1 mcg/kg/min was started and continued postoperatively to prevent effects of residual histamine release. The patient was shifted to the intensive care unit for ventilatory support. Bedsides echocardiography showed empty cardiac chambers. Ultrasound-guided right internal jugular vein cannulation was performed, and the central venous pressure was 3 cm H2O. Then, 500 ml lactated ringer solution and 500 ml 6% hydroxyethyl starch were administered in 30 min resulting in the reduction of the pulse rate from 154 to 122/min and an increase of the blood pressure from 80/55 to 102/69 mmHg. Adrenaline infusion was continued and slowly tapered over the next 8 h. The patient was weaned from the ventilatory support and was extubated the next morning. Further course was uneventful, and the patient was discharged on the 10th postoperative day with an advice to come back after 4 weeks for an intradermal skin testing in the intensive care unit to confirm that ranitidine produced anaphylaxis. The patient and her relatives were alerted and educated that ranitidine was the probable cause for the event.