Complete atrioventricular nodal block after propofol administration in an elderly patient undergoing total knee replacement arthroplasty -A case report-
An 80-year-old woman (weight, 53 kg; height, 154 cm) was scheduled for TKRA of the left knee due to degenerative joint disease. She was diagnosed with hypertension 1 year ago but did not receive any medication. Preoperative blood and coagulation tests were normal. She had not undergone any previous operations. At admission, her vital signs were stable. Preoperative electrocardiography (ECG) showed normal sinus rhythm and a complete right bundle branch block (). A chest X-ray showed a hypertensive heart contour. We did not perform an echocardiogram, because it was obtained at another hospital, and cardiac function was normal except for the hypertension.\nThe patient was premedicated with glycopyrrolate 0.2 mg intramuscularly 30 min before anesthesia. Upon arrival in the operating room, standard ECG, pulse oximeter, noninvasive blood pressure, and bispectral index monitoring (Model A-2000; Aspect Medical Systems, Newton, MA, USA) were applied. Her vital signs were pulse rate, 76 beats/min (bpm); oxygen saturation, 97%; and blood pressure, 177/83 mmHg. Anesthesia was induced with 40 mg lidocaine and 60 mg propofol. Rocuronium was given at a dose of 0.6 mg/kg to facilitate endotracheal intubation after loss of consciousness. After a few minutes, the ECG showed a complete AV block and ventricular rhythm of about 40 bpm (). Despite the administration of 0.5 mg atropine, the arrhythmia persisted (blood pressure, 90/40 mmHg; pulse rate, 30-49 bpm). At that time, her trachea was intubated with a 7.0-sized endotracheal tube under direct laryngoscopy, and a radial arterial line was placed for continuous arterial pressure monitoring and blood gas analysis. A central venous catheter was also inserted via the right internal jugular vein catheter. About 10 minutes after the propofol injection, her blood pressure was 145/55 mmHg, and her pulse rate was 66 bpm. The ECG showed a sinus rhythm. The operation was delayed, and she was transferred to the intensive care unit until fully awake for close observation and further evaluation.\nWe assessed the patient's creatine kinase-MB, troponin T, and myoglobin, and all values were normal. An echocardiography taken the next day exhibited a left ventricular ejection fraction of 63%, which was suggestive of an indeterminate left ventricular filling pattern due to complete AV block. In addition, a 24-h ECG Holter monitor showed AV dissociation. Three-dimensional (3D) computed tomography of the heart revealed that the proximal and middle parts of the left anterior descending artery were narrowed by 50%. She also had a focal aortic valve and mitral annular calcification.\nWe had planned to perform the surgery again. She received a temporary pace maker (VDD mode) with the minimum rate was set to 60 bpm. She was taken to the operating room, where her blood pressure was 180/95 mmHg and pulse rate was 72 bpm. A 22-gauge catheter was placed in the left radial artery for blood pressure monitoring. A central venous catheter was already inserted via the right internal jugular vein. The patient was placed in the right lateral decubitus position, and spinal anesthesia was performed at the L4/L5 interspinous space with 0.5% hyperbaric bupivacaine 8 mg. The sensory level reached the 10th thoracic segment. The surgeon then began the operation with an initial blood pressure of 170/80 mmHg and a heart rate of 90 bpm. The operation lasted about 2 h. She asked for sedation and we administered midazolam 3 mg intravenously. However, because adequate sedation was not achieved, she received a continuous infusion (50 µg/kg/min). A few minutes after the propofol infusion, the ECG showed a complete AV block with a ventricular rhythm of about 40 bpm. The complete AV block disappeared soon after the propofol infusion was stopped. During the remainder of the surgery, her vital signs were stable. At the end of the operation, she had a blood pressure of 150/55 mmHg, a pulse rate of 55 bpm, and oxygen saturation of 96%.\nA permanent pacemaker (DDDR mode) on postoperative day 2 was inserted (). On postoperative day 27, she remained hemodynamically stable and was discharged from the hospital uneventfully.