Optimal blood flow for cooled brain at 20 degrees C.

BACKGROUND: Optimal conditions for deep hypothermic perfusion and protective brain blood flow remain unclear. METHODS: Dogs (n = 52) underwent 120 minutes of cardiopulmonary bypass at 20 degrees C with perfusion flow rates of 2.5, 5, 10, 20, 40, and 100 mL x kg(-1) x min(-1). We examined the effect of the various flow rates and different perfusion pressures on brain blood flow, metabolism, and intracellular pH. RESULTS: The brain was ischemic and acidotic when the perfusion flow rate was less than 5 mL kg(-1) x min(-1) and pressure was less than 10 mm Hg. When perfusion pressure was higher than 10 mm Hg, cerebral cortex blood flow was more than 9 mL x 100 g(-1) x min(-1) and intracellular pH, higher than 6.95. The cerebral metabolic rate for oxygen decreased at a flow rate of 2.5 mL x kg(-1) min(-1). The cerebral metabolic ratio of glucose to oxygen and the cerebral vascular resistance were lowest when perfusion pressure was 10 to 30 mm Hg. Full-flow (100 mL x kg(-1) x min(-1)) perfusion caused paradoxical brain acidosis; a flow of 40 mL x kg(-1) x min(-1) provided the best results. CONCLUSIONS: Both extremely low-flow perfusion and excessive perfusion cause brain acidosis. Low-flow perfusion at a pressure of 20 mm Hg provides cerebral vasorelaxation and aerobic metabolism during operations at 20 degrees C.

[Results of muscle flap repair for deep mediastinitis and graft patency after coronary artery bypass grafting].

Between 1978 and 1997, 9 patients developed poststernotomy mediastinitis after coronary artery bypass grafting. Four of these patients (group A) were treated with open drainage and mediastinal irrigation or omental transfer. The other 5 patients (group B) were treated with primary wound closure by the technique of muscle flap mobilization. The purpose of this study was to compare the surgical results and graft patency of both groups. The hospital mortality of group A was 100 per cent. All patients in group B survived for 35 months of the mean postoperative periods without complaints. Postoperative coronary angiography revealed the complete graft patency in group B. We conclude that muscle flap mobilization may be a superior measure for the patient survival and graft patency as the treatment of mediastinitis after coronary artery bypass grafting.

[Use of ultrasonically activated scalpel for the paced patient--a case report].

A paced patient underwent mitral valve replacement for mitral stenosis using ultrasonically activated scalpel. There were minimum bleeding and no homologous blood transfusion was required. Ultrasonically activated scalpel fid not interfere the pulse generator nor the transesophageal echocardiography. Ultrasonically activated scalpel is useful for the open heart surgery in paced patients.

Ruptured aneurysm of the ductus diverticulum into the pulmonary artery in a man: a successful repair.

Aneurysm of the ductus diverticulum in the adult is rare and its rupture is fatal. A 75-year-old man presented with congestive heart failure that suddenly occurred with a continuous murmur. Angiography showed a left-to-right shunt through a large thrombosed aneurysm of the ductus diverticulum (6 cm), and the pulmonary-to-systemic flow ratio was 2.6. Patch closure of the orifice (3x4 cm) of the aneurysm and repair of the perforated pulmonary artery were done emergently under hypothermic cardiopulmonary bypass with selective cerebral perfusion. He recovered uneventfully. Early recognition and early intervention should be indicated in this otherwise fatal condition.

Regional tissue blood flow and pH in the brain during deep hypothermic retrograde brain perfusion.

Deep hypothermic retrograde brain perfusion is used to protect the brain during aortic arch operations. However, all experiments have failed to demonstrate retrograde blood flow in the brain tissue. We developed an experimental model of sagittal sinus and simultaneous superior vena cava perfusion. Brain tissue blood flow was mapped with colored microspheres during deep hypothermic retrograde brain perfusion in 9 dogs. Regional brain pH was mapped photometrically using neutral red as a pH-indicating dye after 90 min of retrograde brain perfusion in 28 dogs and after 60 min of circulatory arrest in 8 dogs. Cerebral surface blood flow was also measured during retrograde brain perfusion. They were analyzed as functions of driving pressure between sagittal sinus and aorta. Total brain blood flow (ml/min/100 g) was 1.4 +/- 1.3, 3.8 +/- 2.6, and 4.6 +/- 2.6 when the driving pressure was 15, 25, and 35 mmHg, respectively (P < 0.05, 15 mmHg vs 25 mmHg). Regional cerebral blood flow (ml/min/100 g) with a driving pressure of 25 mmHg was 12.1 +/- 9.4, 7.0 +/- 5.6, 4.4 +/- 2.8, and 2.2 +/- 1.4 in the frontal cortex, anterior, mid, and posterior cerebrum, respectively. Cerebral cortex pH was 6.86 +/- 0.23, 7.15 +/- 0.18, and 6.46 +/- 0.13 after 90 min of retrograde brain perfusion with driving pressure of less than 20 mmHg, after that of above 20 mmHg, and after 60 min of circulatory arrest, respectively. Brain tissue pH, blood flows measured with microspheres, and laser flowmetry were highest when driving pressure was between 25 and 35 mmHg. We conclude that retrograde brain perfusion may provide maximum brain protection with driving pressure of 25 to 35 mmHg.

[Oozing type left ventricular rupture: report of three cases].

Two cases of postinfarction oozing type left ventricular rupture and a case of oozing type left ventricular rupture due to catheter perforation for left ventriculography are reported. The technique used to repair the rupture is fibrin glue-oxycellulose fixation method. The post operative course of three cases were uneventful. But left ventricular aneurysm remained in two cases.

[A left subclavian arterial aneurysm caused by fibromuscular dysplasia: a case report].

A 70-year-old man complained left supraclavicular pulsatile tumor. Angiography and CT revealed the left subclavian arterial aneurysm that was just behind the clavicle. The aneurysm was resected through a cross-clavicle incision and an 8 mm Hemashield graft was implanted. The pathological study showed change of fibromuscular dysplasia. The post-operative course was uneventful.