Recurrent paroxysmal supraventricular tachycardia in the beach chair position for shoulder surgery under general anesthesia

provided the original work is properly cited. CC The beach-chair position is commonly used for shoulder surgery. Its advantages include ease of setup, less intraoperative blood loss, and a lower incidence of traction neuropathy [1]. However, caution is required as the position may induce undesirable physiologic changes including decrease in mean arterial pressure and cardiac index, and increase in peripheral vascular resistance [2]. Other serious complications include venous air embolism [3] and hemodynamic instability [4]. We experienced a case of recurrent paroxysmal supraventricular tachycardia (PSVT) progressing to pulseless electrical activity accompanied by hypotension during shoulder surgery performed in the beach-chair position. An 89-year-old female patient weighing 32 kg with a height of 145 cm presented for open reduction of nonunion of surgical neck fracture of the left humerus. She had been diagnosed with hypertension 5 years previously, and her current medications included benidipine, a calcium channel blocker, and thiazide, a diuretic. Preoperative laboratory tests were unremarkable. Chest radiography revealed cardiomegaly, and electrocardiogram showed left ventricular hypertrophy. Echocardiogram showed normal left ventricular systolic function with an ejection fraction of 65%. No premedication was given. Vital signs checked upon arrival in the operating room revealed heart rate of 95 beats per minute, blood pressure of 160/90 mmHg, and pulse oximetry at 95%. For induction of anesthesia, 30 mg of lidocaine, 50 mg of propofol, and 30 mg of rocuronium bromide were administered intravenously. Intubation was performed using a 7.0 mm cuffed tube. Anesthesia was maintained with 50% N2O-O2, sevoflurane 1.5 vol%, and remifentanil 0.05 μg/kg/min. For continuous monitoring of the arterial pressure and access to arterial blood gas analysis, a 22 gauge catheter was placed in the right radial artery. The patient's position was changed from supine to the beach-chair position. Invasive arterial blood pressure was measured with a transducer placed at the heart level. About 1-2 minutes after initiation of the beach-chair position, the blood pressure dropped to 85/35 mmHg. 50 μg of phenylephrine was administered intravenously, and the operation was continued with dopamine being infused at 5 μg/kg/min. Blood pressure was maintained around 110/65 mmHg. About one hour after the operation had begun, sudden tachycardia with a heart rate of 140 beats per minute occurred for 3 seconds before returning to normal sinus rhythm. Ten minutes later, the tachycardia recurred with a heart rate of 140 beats per minute. Normal sinus rhythm was recovered after administration of 10 mg of intravenous esmolol. Five minutes after the second tachycardia, a heart rate of 150 beats per minute was noted. Again, normal sinus rhythm was recovered with 10 mg of esmolol. However, as the basal heart rate was increased to 100 beats per minute, continuous administration of amiodarone at a rate of 15 mg per minute was begun. In addition, under the impression of tachycardia caused by hypovolemia, transfusion of one pint of packed red cells was started. Tachycardia of 150 beats per minute occurred again five minutes after the third tachycardia. Blood pressure dropped to 60/40 mmHg and echocardiogram showed loss of p waves and narrow QRS complexes (Fig. 1). The Valsalva maneuver was applied under the impression of PSVT