A 44-year-old female patient, 155 cm in height and 65 kg in weight, who visited our hospital with a main complaint of dysmenorrhea and hypermenorrhea was diagnosed with uterine myoma and decided to undergo a laparoscopic assisted vaginal hysterectomy. The patient's past medical history showed that she had a cystectomy for an ovarian tumor ten years ago and subtotal-thyroidectomy for thyroid cancer five years ago. The patient was taking 0.15 mg of Synthroid once a day. Since the preoperative hemoglobin levels were 7.8 g/dl, two units of packed red blood cells were transfused. There was no other specific finding in the preoperative examination.
For preanesthetic medication, an intramuscular injection of 0.2 mg of glycopyrrolate was given. Electrocardiography, noninvasive blood pressure monitoring, pulse oxymetry, and Bispectral index (BIS) monitoring (A-3000 EEG BIS monitor, Aspect Medical system, USA) started immediately after the patient arrived at the operation room. The vital signs before the induction of anesthesia were as follows; a blood pressure of 139/87 mmHg, a heart rate of 70/min, and a pulse oxygen saturation of 99%. For the induction of anesthesia, 120 mg of propofol and 40 mg of lidocaine were mixed and intravenously injected. Then, 100 mg of succinylcholine was intravenously injected for endotracheal intubation. During the endotracheal intubation, 7 mm of a single endotracheal tube was fixed with the point marked with "21 cm" attached to the lips after checking that breathing sound was well heard on both sides. Vecuronium 4 mg was intravenously injected to maintain muscle relaxation, and 2-3 vol% of sevoflurane, 2 L/min of oxygen, and 2 L/min of nitrous oxide were used to maintain the anesthesia. The tidal volume was regulated to keep the end-tidal CO
2 pressure at 30-35 mmHg, and the depth of the anesthesia was controlled to maintain a BIS index of 40-60. The laparoscopic assisted vaginal hysterectomy began with the patient in the lithotomy position. The operation continued without any problems, and the vital signs of the patient were stably maintained. The intra-abdominal pressure was kept at 10-15 mmHg. Suddenly, at two hours after the initiation of the operation, the blood pressure dropped from 110/63 mmHg to 78/41 mmHg, end-tidal CO
2 pressure dropped from 45 mmHg to 20 mmHg, and the pulse oxygen saturation dropped to 70%. The peak airway pressure increased from 23 cmH
2O to 33 cmH
2O, and the heart rate increased from 70/min to 125/min. Promptly, 5 mg of ephedrine and 100 µg of phenylephrine were intravenously injected two times at five-minute intervals. Intravenous injection of 10 mg of ephedrine was then done, but the blood pressure did not increase. After 100 µg of epinephrine was injected, the blood pressure increased to 182/117 mmHg, the heart rate increased to 140/min, and the pulse oxygen saturation was maintained at 100%. Following the intravenous injection of 15 mg of esmolol, the patient remained in a stable state with the blood pressure at 107/74 mmHg, heart rate at 103/min, pulse oxygen saturation at 100%, end-tidal CO
2 pressure at 35 mmHg, and peak airway pressure at 20 cmH
2O. For continuous arterial pressure monitoring, a 22-gauge catheter was inserted into the radial artery in the left arm and invasive blood pressure monitoring was started. The results of the arterial blood gas analysis done at that time were a pH of 7.412, a PaCO
2 of 38.9 mmHg, a PO
2 of 173 mmHg, and oxygen saturation at 99.8% (FiO
2: 0.5). Massive carbon dioxide embolism, pulmonary thrombus, tension pneumothorax, and right atrial thrombus were suspected as the cause, and a transesophageal echocardiography (HDI3000, PHILIPS, Netherlands) was done to differentiate the cause and evaluate cardiac function. A lesion that looked like a lump was found in the right atrium, and the size shown on the monitor was 2.8 × 4.1 cm. The shape of the lesion was round. A freely-moving echo-density was found in the region that did not overlap the right atrium, although the overall motion was not great (
Fig. 1). The right atrium and the right ventricle were not hypertrophied but the size of the right atrium was larger than normal. The interventricular septum was moved toward the right ventricle in the systole. The motion of the tricuspid valve was normal, but the tricuspid regurgitation or pulmonary artery pressure could not be measured because of the lump density. The function of the left heart was normal, and thrombosis in the aorta was not suspected. We assumed that the partial movement of the thrombus to the pulmonary artery might have caused the pulmonary thrombosis because the initial vital signs had not been good even though the vital signs were normal since the thrombus was localized to the right atrium. Confirming that it was right atrium thrombosis with a cooperative diagnosis from a thoracic surgeon and a cardiology specialist, we decided to perform a thromboembolectomy, which is the most rapid treatment, and received consent from the caregiver after providing an explanation on the patient's condition since we assumed that the same phenomena could occur once again even though the vital signs were normal at that time. Although thromboembolectomy had to be rapidly performed for the treatment of right atrium thrombosis, we decided to perform it after a simple hemostasis in the obstetrics and gynecology department because the vital signs were stable at that time. No specific change was found in the right atrium thrombus during the hemostasis.
The hemostasis was finished after about 20 minutes, and a central venous catheter was inserted through the right internal jugular vein for the thromboembolectomy. The method for anesthetic maintenance was changed to intravenous injections of 10 µg/kg/h of fentanyl, 50 µg/kg/h of midazolam, and 0.2 mg/kg/h of vecuronium. When preparing for the thromboembolectomy, there was no change in the electrocardiography, capnography, end-tidal CO
2 concentration, and airway pressure, and no hemodynamic change was found in the blood pressure, heart rate, and pulse oxygen saturation. After sternotomy was performed in the operation, we observed all the other structures in the heart using transesophageal echocardiography, but the thrombus that had existed in the right atrium was not found. Even though there was no symptom or sign that suggested movement of the thrombus to the pulmonary artery, we were not able to judge that the thrombus was spontaneously resolved. Since the possible movement of the thrombus to the pulmonary artery or other structures could not be explicitly excluded, we decided to continue the operation after consulting with the thoracic surgeon and the cardiology specialist. Aortic cannulation, superior vena cava cannulation, and inferior vena cava cannulation were smoothly performed. Following the aortic cross clamp, cardiac arrest was carried out using a cardioplegia, and open-heart surgery was done under cardiopulmonary bypass. During the cardiopulmonary bypass, the activated clotting time (ACT) was maintained for more than 480 seconds. Since the thrombus was found neither in the right atrium nor at the origin of the pulmonary artery, the catheter was deeply inserted into the right pulmonary artery and a few thrombi, 7 mm long and 2 mm thick, were eliminated by suction. The thrombi found during the operation were much smaller than the thrombus found by the transesophageal echocardiography before, but the right atrium was sutured because no more thrombus was found and there were no abnormal findings in the other regions. Cardiac function was spontaneously recovered without defibrillation, and the ACT was reversed to 145 seconds before weaning from the cardiopulmonary bypass. Transesophageal echocardiography was performed to verify cardiac function recovery and the existence of a thrombus and no specific problems were found (
Fig. 2). However, another operation was performed for the purpose of hemostasis just after the thromboembolectomy since the bleeding was severe at the region where the operation was performed in the obstetrics and gynecology department. During the entire operation, 16 units of packed RBCs, 8 units of fresh frozen plasma, and 8 units of platelets were transfused.
After the operation in the obstetrics and gynecology department, the patient was transferred to the intensive care unit without reversing muscle relaxation. Extubation was performed after the patient's consciousness and muscle strength recovered on the first day after the operation. The D-dimer level increased to 8.24 µg/ml, but lung perfusion scanning did not show any pulmonary thrombus. The patient was transferred to the general ward on the second day. The lower extremity vein Doppler scanning performed on the 14th day did not show any deep vein thrombi. The postoperative transthoracic echocardiography showed normal cardiac functions. The patient was discharged on the 30th day after the operation without any problems.