Allopurinol dosage and effect on ischemia-reperfusion damage in elective and acute aortic surgery.

To study the effect of a safe dosage of allopurinol on ischemia-reperfusion damage following aortic surgery, 24 patients undergoing either elective or acute aortic reconstruction, were randomized to receive allopurinol or placebo, yielding four groups: elective/placebo (EP), elective/allopurinol (EA), acute/placebo (AP) and acute/allopurinol (AA). Blood concentrations of allopurinol, oxypurinol, uric acid, malondialdehyde, ascorbic acid, and 99mTc-albumin were determined perioperatively. Adequate concentrations and biochemical activity of allopurinol and oxypurinol were obtained, without side-effects. Malondialdehyde did not increase perioperatively, but was significantly higher in acute surgery than in elective surgery intraoperatively. Yet, ascorbic acid levels and 99mTc-albumin disappearance were not different from groups EP and EA. No influence of allopurinol was found on malondialdehyde, ascorbic acid and 99mTc-albumin. An influence of allopurinol may have been obscured, as patients in group AA were more hypotensive than in group AP. In conclusion, adequate allopurinol concentration can be obtained with a safe dosage in abdominal aortic surgery. Signs of ischemia-reperfusion injury were found in acute surgery, not in elective surgery. Therefore, further investigation on the clinical effect of allopurinol is only useful in acute aortic surgery.

Analysis of post-operative hypalbuminaemia: a clinical study.

OBJECTIVE: Analysis of severity, causes and relevance of hypalbuminaemia developing after surgery. SUBJECTS: Patients undergoing elective aortic surgery (n = 11) or minor extra-abdominal surgery (n = 6). METHODS: Serum albumin concentration, blood loss, nitrogen balance and complications were determined until the fifth post-operative day. The contributions of haemodilution, albumin loss, albumin catabolism and redistribution were calculated using existing formula. The relation of hypalbuminaemia to the endocrine-metabolic response was determined. RESULTS: Significant hypalbuminaemia occurred after aortic surgery, in the absence of significant complications. No haemodilution occurred. Analysis indicated that 18% of hypalbuminaemia was caused by blood loss. Only 6% could be attributed to albumin catabolism, despite a significant correlation with the endocrine-metabolic response. Seventy-seven percent of hypalbuminaemia was attributed to albumin redistribution. No hypalbuminaemia occurred after minor surgery. CONCLUSION: Post-operative hypalbuminaemia is a normal finding early after aortic surgery. It is mainly caused by albumin redistribution, not by metabolic changes.

Endocrine-metabolic response to abdominal aortic surgery: a randomized trial of general anesthesia versus general plus epidural anesthesia.

The influence of epidural anesthesia on the endocrine-metabolic response following abdominal aortic reconstruction was studied in a prospective randomized trial. Cortisol and catecholamine responses and nitrogen balance were measured in two groups of five patients receiving general anesthesia only (group 1) or general anesthesia combined with epidural bupivacaine (group 2). The study lasted from preoperatively until the first postoperative day. At 2100 hours on the day of surgery serum cortisol concentrations were higher in group 1 than in group 2 (1.41 versus 0.82 mumol/L; p < 0.01). Likewise the total perioperative hypercortisolemia, expressed as the area under the curve, was significantly higher in group 1 (11.7 versus 5.7 mumol/L/hr, p < 0.01). Intraoperative urinary excretion of epinephrine and postoperative norepinephrine excretion were significantly higher in group 1 than in group 2. Urinary excretion of free cortisol and cumulative nitrogen balance were not different between the groups. Although the number of patients was limited and the sensory nerve block level was not measured perioperatively, this study suggests that epidural anesthesia attenuates the stress response to aortic surgery.