Shigeru Kazama

Effect of altering cerebrospinal fluid pressure on spinal cord blood flow

Removal of cerebrospinal fluid (CSF) has been proposed as a means of protecting the spinal cord against ischemic injury during thoracoabdominal aneurysm operations. We investigated the effect of altering CSF pressure (CSFP) on lumbar spinal cord blood flow (SCBF) in an experiment using dogs. The SCBF was measured before and after withdrawal of CSF in settings with and without thoracic aortic clamping. Furthermore, SCBF was measured at the basal state and after elevation of CSFP to 20 mm Hg and to 40 mm Hg. The SCBF did not change significantly before and after removal of CSF in settings both with and without thoracic aortic clamping. Elevation of CSFP significantly reduced SCBF. Elevation of CSFP reduces SCBF, but lowering CSFP per se does not increase SCBF whether the thoracic aorta is occluded or not. This supports the notion that removal of CSF offers spinal cord protection only when CSFP is abnormally elevated.

Fabric heart retractor for coronary artery bypass operations

A new device for heart retraction during coronary artery bypass operations has been developed. It provides safe and steady support and an unobstructed view of the lateral, posterior, and inferior surfaces of the heart; in addition, it is easy to handle.

Protection of the spinal cord with pentobarbital and hypothermia

BACKGROUND Ischemic spinal cord damage during thoracic aortic operations has not been eliminated despite application of various adjuncts. We experimentally investigated the protective effects of pentobarbital and hypothermia on the spinal cord subjected to ischemia. METHODS Among nine groups of 6 rabbits each, groups AI to AIII underwent 20-minute infrarenal aortic occlusion, and groups BI to BVI underwent 40-minute occlusion. Five milligrams per kilogram of pentobarbital was administered to groups AII and BII; 10 mg/kg in groups AIII, BIII, and BVI; 20 mg/kg in group BIV; and none in groups AI, BI, and BV. In groups BV and BVI, hypothermia was induced. Forty-eight hours postoperatively, the motor function of the lower limbs was evaluated. RESULTS Statistically significant recovery of motor function was observed in animals in groups AII, AIII, BIII, BIV, BV, and BVI. CONCLUSIONS Pentobarbital showed dose-dependent protective effects of the spinal cord. Moderate hypothermia alone also showed protective effects. Combined use of pentobarbital and hypothermia resulted in highly significant recovery of spinal cord function.

Simplified physiological pacing after cardiac surgery.

Temporary pacing wires are routinely placed at the end of cardiac surgery. These pacing wires are helpful in maintaining patients with postoperative bradycardias, and physiological pacing is also more desirable in critically ill patients. We herein report our simplified procedure for atrial pacing. This technique uses commercially available intravenous pacing catheters. The catheter is passed through the skin, and its tip is placed at the pericardial oblique sinus just between the right and left pulmonary veins. Atrial pacing is then initiated with a temporary pulse generator. This procedure is simple and effective for patients undergoing cardiac surgery. We also report two clinical cases that satisfactorily underwent atrial pacing using this procedure.