[Two Cases of Convulsive Seizures after Cardiac Surgery Suspiciously Caused by Tranexamic Acid Administration in Patients on Chronic Hemodialysis].

Tranexamic acid (TA), an antifibrinolytic agent, is commonly used in cardiac surgery with cardiopulmo- nary bypass to reduce bleeding. We report two cases of convulsive seizures after cardiac surgery with chronic kidney disease on hemodialysis. The two patients underwent aortic valve replacement, one for aortic valve regurgitation and another for aortic valve stenosis, with cardiopulmonary bypass uneventfully. A total dose of 8 g of TA was administered intravenously; 4 g during and 4 g after cardiopulmonary bypass. Both patients developed two episodes of gener- alized convulsive seizures post-operative day 1, which were suppressed by administration of diazepam intra- venously. The blood test, brain CT and electroenceph- alogram revealed no significant abnormalities. They were discharged without any neurological complica- tions. The high dose of TA was considered to have caused the seizures, since in previous reports the use of TA during surgery was associated with increased risk for postoperative seizures. It was demonstrated that approximately 40 to 70% of TA is excreted in the urine following intravenous administration. We posit that this might have led to excessive serum concen- tration of TA in our patients. Therefore, the dosage of TA should be decreased judiciously in patients with chronic kidney disease especially on hemodialysis to prevent postoperative seizures.

[Anesthetic Induction in a Patient with Giant Ovarian Tumor Who Developed Severe Hemodynamic Instability].

A 45 year-old woman underwent a laparotomy for a giant ovarian tumor under general anesthesia. Preoperative CT scan revealed a 30 cm-diameter tumor compressing IVC. She had slight respiratory discomfort on supine position, but respiratory function test showed no abnormalities. In the operating room, after oxygenation for 3 minutes, general anesthesia was induced with fentanyl 100 µg, propofol 90 mg and rocuronium 40 mg on supine position. Immediately after the induction, her systolic blood pressure and heart rate fell to 45 mmHg and 40 beats per minute, respectively. We considered that her hemodynamic instability was supine hypotensive syndrome due to giant ovarian tumor. Therefore we placed her 30 degree right side up and pushed her tumor to the left so as not to compress the IVC. We rapidly injected acetated Ringer's solution 500 ml, ephedrine 12 mg and phenylephrine 0.1 mg, and her hemodynamic status soon recovered to normal ranges. The anesthetic induction of a patient with a giant ovarian tumor is challenging. Some reports recommend strategies such as induction on lateral position or suctioning tumor contents before induction. Careful induction of general anesthesia is required for these patients.

[Awake epidural anesthesia for thoracotomic drainage in a high-risk patient with postoperative severe pneumonia complicated with empyema].

An 84-year-old man successfully underwent thoracotomic drainage for empyema under awake epidural anesthesia. His past history had revealed significant chronic obstructive pulmonary disease due to smoking. He had undergone right lower lobectomy a month before, but his postoperative course was complicated with pulmonary leakage, severe pneumonia and empyema which required intensive care management. A thoracotomic drainage for empyema was managed under awake thoracic epidural anesthesia using fentanyl and 1% lidocaine because of concern about deterioration of respiratory status following general anesthesia. The additional small doses of fentanyl i. v. and local anesthesia infiltration were needed for resection of 9th rib, but otherwise the drainage was managed successfully. Awake epidural anesthesia was very useful for such a high-risk patient with poor respiratory status.

[Left ventricular migrating thrombus detected by intraoperative transesophageal echocardiography].

Transesophageal echocardiography (TEE) helps detecting intra-cavity thrombus size, mobility and fragility, which are of great importance in surgical removal of the thrombus. Thrombus characteristics may render surgical thrombectomy incomplete, raising the risk of catastrophic embolization. A 50-year-old man, suffering from congestive heart failure, developed a mobile thrombus in the left ventricle (LV). He was scheduled for a LV thrombectomy. TEE showed two thrombi on the apical side of the left ventricle, measuring 2.1 x 1.3 cm and 2.1 x 1.0 cm each. A surgical removal of these thrombi was performed under cardiopulmonary bypass (CPB). Just before separation from CPB, TEE detected a high echogenic mass in the LV Surgical re-explorations found residual thrombi, whose size, figure and echo signal strength resembled papillary muscles. This experience leads us to advocate repeated search for thrombi using TEE scans, in order to facilitate complete removal of thrombi prior to closing the ventriculotomy, and prior to weaning from CPB.