Usefulness of the bispectral index during cardiopulmonary resuscitation -A case report-
A 40-year-old woman (161 cm, 67 kg) at 36 and 6/7 weeks gestation with placenta previa totalis, visited the hospital for a Cesarean section. She had delivered her first baby by Cesarean section roughly 10 years earlier. The patient had a myomectomy 9 years earlier, due to myoma in the low portion of uterus. The results of the preoperative laboratory tests were normal. Invasive arterial blood pressure monitoring was started before anesthesia, due to the anticipation of a large amount of intraoperative bleeding by placenta previa.\nAnesthesia was induced with intravenous injection of thiopental sodium 250 mg and succinylcholine 66 mg. After a successful intubation, anesthesia was maintained with sevoflurane 1.2 vol% and 50% nitrous oxide. The patient was ventilated by a volume-controlled mode with 50% oxygen. Monitoring devices, such as electrocardiogram (EKG), BIS, and pulse oximetry were used. The ventilator was set to end-tidal carbon dioxide (EtCO2) partial pressure 30-35 mmHg.\nAfter intubation, an additional 25 mg atracurium was injected intravenously. The baby was delivered 9 min after the induction of anesthesia. The baby's Apgar scores at 1 and 5 min were 8 and 9 points, respectively. There were no complications with the fetus. After the placenta was removed, bleeding was observed in the uterus at placental attachment sites. An intravenous injection of 0.2 mg methyl ergonovine for uterotonic effect, and a central venous catheter was inserted in the right internal jugular vein. Packed RBCs were administered through a central venous catheter, and the patient's vital sign remained stable (systolic and diastolic blood pressure 110-120/70-80 mmHg, heart rate 75-85 beats/min, BIS 50-65).\nThe surgeon finished the uterine suture one hour and 40 minutes after the operation. At that time, the patient's EtCO2 partial pressure and blood pressure dropped abruptly. EtCO2 partial pressure was 15 mmHg, systolic blood pressure was 60 mmHg, SpO2 was 90% and ventricular fibrillation appeared. The operation was stopped immediately, chest compression was started, and additional help was requested.\nDefibrillation using biphasic defibrillator in 200 Joule was attempted; epinephrine, atropine, and bicarbonate were injected; and chest compression was continued. However, the patient's normal sinus rhythm did not return. Fortunately, systolic blood pressure was maintained at approximately 60-100 mmHg, depending on the cardiac compression. Despite manual ventilation with 100% oxygen, the patient's arterial oxygen saturation was 86%, as checked by arterial blood gas analysis (ABGA). Additionally, a significant amount of a blood-like secretion exited the endotracheal tube and EtCO2 partial pressure was checked as apnea (PH 7.32, PaCO2 35 mmHg, PaO2 56 mmHg, HCO3- 18.0 mmol/L, and SaO2 86.0%). However, BIS values were maintained above 40. Cardiac compression was attempted for 40 minutes, defibrillation was performed three times and epinephrine 60 mg, atropine 5 mg, bicarbonate 120 mEq, calcium chloride 1,200 mg were used. The heart rhythm did not return, despite BIS values remaining above 40 during CPR. CPR was not stopped.\nDue to the vigorous flow of blood-like secretion from the endotracheal tube, the corrugating tube was exchanged five times, EtCO2 partial pressure monitoring was stopped, and the tube was continuously suctioned. Manual ventilation was maintained with 100% oxygen. After 50 min of CPR, there was an abrupt return of a normal sinus rhythm. The patient's blood pressure was 90/50 mmHg, and her heart rate was 110 beats/min. Twenty percent mannitol 100 ml, lasix 20 mg, and methylprednisolone 500 mg were injected intravenously to protect the vital organs. Obstetricians completed the operation by re-stitching the wound. There was no urine output during CPR, but urine was excreted at a rate higher than 200 ml/hour once spontaneous circulation was restored.\nNo uterine bleeding was observed by the naked eye through a vaginal speculum, and a hysterectomy was not performed. However, after an hour, the patient developed vaginal bleeding, and her heart rate increased to 120-130 beats/min. Therefore, a hysterectomy was performed, and a transesophageal echocardiography (TEE) probe was inserted. The thrombus in the heart was not found, but there was global hypokinesia in the left ventricle. The results of the lab measurements were a platelet count of 39,000, a prothrombin time (PT) of 28.6 sec, an activated partial thrombin time (aPTT) of 129.1 sec, fibrinogen at 60 mg/dl, and a d-dimer > 20 µg/ml. A disseminated intravascular coagulation (DIC) by amniotic fluid embolism was suspected, and 3 units of whole blood, 10 units of pack cells, 20 units of platelets, and 10 units of fresh frozen plasma were transfused during the surgery. Total anesthesia time was 8 hours and 40 minutes.\nAfter the surgery, the patient was transferred to the intensive care unit. Chest radiography showed pulmonary edema in both lungs. She was treated with transfusion and fluid therapy, due to a suspected DIC by amniotic fluid embolism. Two hours after the operation, she recovered to a drowsy state and responded to pain stimulation.\nSix hours after the operation, the pulmonary edema showed a slight improvement on chest radiography, and a transthoracic echocardiography (TTE) in the intensive care unit revealed no obvious regional wall motion abnormality. Although breathing with a ventilator, she returned to an alert mental state and was cooperative sixteen hours after the operation. Extubation was performed, and vital signs were stable. (pH 7.605, PaCO2 25.3 mmHg, PaO2 98.5 mmHg, HCO3- 24.6 mmol/L, and SaO2 98.4%, hemoglobin 9.9 g/dl, platelet 108,000, PT/aPTT, 16.6/48.5 sec, fibrinogen 263 mg/dl, d-dimer 4.51 µg/ml).\nThirty min after the extubation, the patient experienced a sudden loss of consciousness, and cardiac arrest developed again. Once defibrillation was performed, her mental state and heart rhythm recovered immediately. After seven hours, she showed tachyarrhythmia and cardiac arrest. Five days after surgery, the patient's condition continued to deteriorate, and she developed multi-organ failure. Thus patient was supported by extracorporeal membrane oxygenation (ECMO) and continuous renal replacement therapy (CRRT). Despite aggressive resuscitation, she died 6 days after the surgery.