The 10-year experience of a single community was reviewed and a multivariate analysis was performed to determine the relative importance of clinical and environmental factors in mortality after ruptured abdominal aortic aneurysm resection. Ruptured aneurysms were repaired in 243 patients in six area hospitals (one university, five community) by 25 surgeons (16 vascular, 9 general). Overall, 30-day mortality was 55% (133/243). Although the mortality by hospital ranged from 44% to 68%, these differences were not statistically significant. However, significant variations occurred in the mortality rates of individual surgeons, ranging from 44% to 73%. The mortality rate for the vascular surgeons was less than that of the general surgeons, 51% versus 69% (p less than 0.05). Clinical factors were evaluated, and the most significant parameters were systolic blood pressure, presence of chronic obstructive lung disease, and history of chronic renal insufficiency. These results support the implication that the degree of specialization of the surgeon and the preexisting health of the patient are the most important determinants of survival after ruptured abdominal aortic aneurysm. The size and sophistication of the hospital appear to be less influential factors.

No abstract

A canine model was developed to study the differential response of a gram-negative and a gram-positive bacterial infection on autogenous and prosthetic grafts. After replacing segments of the femoral arteries of 15 dogs with autogenous vein in one groin and polytetrafluoroethylene in the contralateral groin, 108 colony-forming units ofnonmncinproducing Staphylococcus epidermidis (five dogs), Pseudomonas aeruginosa (five dogs), or sterile saline solution (five dogs) were directly inoculated onto the grafts. The grafts were examined 7 to 10 days after implantation. None of the control dogs exhibited inflammatory signs, and no grafts or anastomoses disrupted. S. epidermidis was unrecoverable from either graft material in any of the animals, although histologic evaluation confirmed neutrophils and bacteria in four of five animals in the vein and polytetraffuoroethylene groups. No dog inoculated with S. epidermidis had graft or anastomotic disruption. By contrast, P. aeruginosa was recovered from both types of grafts in all inoculated animals. Nentrophils, bacteria, and microabscesses were observed in all of these animals. In addition, three of five polytetrafluoroethylene grafts and all five vein grafts disrupted either at the anastomoses or in the body of the vein graft. Therefore S. epiderzaidis is a less virulent organism that may persist in graft walls despite negative cultures, whereas P. aeruginosa is a highly virulent organism that can disrupt native artery, vein grafts, and anastomoses. The graft material appears to be less important than the bacteria in determining the outcome of infection.

No abstract

A photoplethysmographic technique was used in 30 consecutive patients who had abdominal aortic reconstruction to assess colonic viability intraoperatively. A sterile pulse oximeter probe was used to measure arterial pulsatility and transcolonic oxygen saturation (TCOS) in the proximal, midportion, and distal sigmoid colon before and after the reconstruction. No attempt at inferior mesenteric revascularization was made, irrespective of the photoplethysmographic results. The status of the colon was assessed between the third and sixth postoperative day by a colonoscopist unaware of the intraoperative data. Before the reconstructive procedure photoplethysmography displayed pulsatile flow in all patients with a mean TCOS of 95% +/- 0.4%. After reconstruction, 28 patients (93%) demonstrated unchanged pulsatility with mean TCOS of 94% +/- 0.4%. Despite ligation of a patent inferior mesenteric artery in 10 of these patients, all 28 had normal colonoscopic examinations. By contrast, two patients (6.7%) had a loss of photoplethysmographic pulsatility with unmeasurable TCOS. Both of these patients had ligation of an initially patent inferior mesenteric artery and demonstrated evidence of ischemic mucosal changes at colonoscopy. Intraoperative colonic photoplethysmography represents an easily performed, accurate method for predicting colonic viability. A loss of pulsatility suggests inadequate postreconstructive colonic perfusion and mandates revascularization of the inferior mesenteric artery.