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Massive coagulopathy and bleeding continues to play a major role in the operative mortality and perioperative multi-system failure of patients requiring elective thoracoabdominal aneurysm repair. It was the purpose of this study to determine the coagulation defect that occurs with supraceliac aortic clamping and the effects of increasing aortic cross-clamp time (AXCT) on the coagulation system and its recovery. Through a standard thoracoabdominal incision, 16 mongrel dogs had their aortas cross-clamped simultaneously just above the diaphragm and at the aortic bifurcation. Animals were divided into four groups of four animals each; sham operation, 30 minute AXCT, 60 minute AXCT, and 90 minute AXCT. Central venous blood was sampled prior to aortic cross clamping (AXC), during AXC and 1 hour, 2 hours, 5 hours, 7 hours, 12 hours, and 24 hours after the clamp was removed. All samples were assayed for platelets, fibrinogen, fibrin split products, prothrombin time (PT) and partial thromboplastin time (PTT). Platelets and fibrinogen decreased as PT and PTT increased with increasing AXCT consistent with disseminated intravascular coagulation (DIC) (P less than .001). Fibrin split products were positive in the 90 minute AXCT group only. The drop in platelets was greater for increasing AXCT and continued to fall in the 30, 60 and 90 minute AXCT groups at 24 hours (p less than .001). Fibrinogen dropped to the lowest levels between two and twelve hours after AXC and returned to normal at twenty-four hours in the 60 and 90 minute AXCT groups (p less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Five cases of thoracoabdominal aneurysms are reviewed. These cases were observed during the last 10 years and their incidence was 4% of all aortic aneurysms admitted in the same period. In all the patients the Crawford's technique by graft inclusion with visceral vessel reattachment by direct suture, without by-pass, was adopted. Of the five patients, two underwent elective surgery and three emergency surgery. While the mortality rate in the patients operated on election was 0%, on emergency it was 66,6%.

Presently we favor heparinless femorofemoral venoarterial bypass for all descending thoracic aneurysm resections. The advantages are minimal blood loss due to the absence of heparin, ease of insertion, especially in large aneurysms where it would be difficult to insert a temporary shunt, distal aortic perfusion, possibly a safety factor in preventing spinal cord and visceral ischemia, and prevention of left heart overload and myocardial failure. In acute traumatic ruptures, simple aortic cross clamping is a suitable alternative. It is safe and can be carried out expeditiously in any community hospital where bypass facilities may not be available. Proximal hypertension can be controlled pharmacologically. We have also used this successfully in ruptured atherosclerotic aneurysms. We have no experience with temporary tridodecylmethylamonium (TDMAC) shunts; several groups have used them successfully. We believe they may be difficult to insert in the proximal aorta with a large mediastinal hematoma or extensive aneurysm. Cannulation of the left ventricular apex necessitates cardiac manipulation and may produce effective aortic valve insufficiency. In patients with aortoesophageal and bronchoesophageal fistula, permanent extrathoracic bypass is preferable to a prosthetic graft in a contaminated field. We propose using a permanent bypass with a no. 10 or 12 right axillofemoral bypass. Our experience is limited to only two patients. This is also a method of treating a mycotic aneurysm or infected thoracic aortic graft.

Seventeen patients undergoing elective repair of abdominal aortic aneurysm were examined to determine the causal mechanism for postoperative hypertension. In nine patients who had elevated systemic pressure after surgery, there were no correlations between mean arterial pressure and values of peripheral renin activity or angiotensin II. Further, no relation was demonstrated between systemic pressure and the volumes of crystalloid, colloid infused or milliequivalents of sodium administered pre- and intraoperatively. Postoperative arterial pressure correlated best with the preoperative value.

Hemodynamic data of 8 patients undergoing planned resection of abdominal aortic aneurysm are statistically analyzed by variance analysis ("patient" factor and "time" factor). The results are: 1. "Patient" factor exists for all the variables studied. 2. "Time" factor is present for some of them. After aortic clamping, there is a significant decrease of the systolic index (p less than 0.05) and of the left ventricular systolic work index (p less than 0.01). After aorting declamping, a high significant increase of the mean right auricular pressure (p less than 0.001) and of mean capillary wedge pressure (p less than 0.001) are seen. Similar results are observed at the end of surgery. The results are commented with regard of the literature.

We address the question of whether an oxygen debt develops during a period of abdominal aortic cross-clamping that may explain observed hemodynamic changes. Group 1 received morphine sulfate (1 mg/kg) during induction of anesthesia. Group 2 received same dose of morphine sulfate. Group 3 received 4 mg/kg of morphine sulfate. We measured the oxygen consumption (VO2) and the carbon dioxide production levels (VCO2), as well as hemodynamic and biochemical parameters. In groups 1 and 3, VO2 and VCO2 decreased 10% to 13% following abdominal aortic cross-clamping compared with values measured before cross-clamping. In group 2, VO2 and VCO2 decreased 3% and 7%, respectively. On unclamping, the greatest increase in VO2 was observed in group 3 (26%), while in groups 1 and 2, VO2 rose 18% and 5%, respectively. In all three groups, metabolic changes were not paralleled by hemodynamic or temperature changes. Results indicate that oxygen debt developed during abdominal aortic cross-clamping, but this has no effect on hemodynamic changes seen after unclamping. Higher dosage of narcotic administered during anesthetic induction did not temper increase in metabolic rate observed after unclamping.