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Biomedical subjects

N P Couch

Publications and source records attributed to N P Couch.

At least 37 records · Page 2Linked to original sources
PubMed1981

The high cost of low-frequency events: the anatomy and economics of surgical mishaps.

We conducted a one-year prospective survey to identify adverse outcomes due to error during care in the field of general surgery. We identified 36 such cases among 5612 surgical admissions to the Peter Bent Brigham Hospital, but in 23 cases the initiating mishap had occurred in another hospital before transfer. In two thirds of the cases the mishap was due to an error of commission: an unnecessary, defective or inappropriate operative procedure. Twenty of these patients died in the hospital, and in 11 death was directly attributable to the error. Five of the 16 survivors left the hospital with serious physical impairment. A satisfactory outcome was achieved in only 11 cases (31%). The average hospital stay was 42 days, with the duration ranging from one to 325 days; the total cost for the 36 patients was $1,732,432. We suggest that all hospitals develop comprehensive methods to identify and prevent these costly and unnecessary events.

Boston↗
PubMed1981

Femorotibial and femoroperoneal bypass vein grafts. A 15-year experience.

Results with 111 femoral-infrapopliteal vein grafts in 105 patients were subjected to life-table analysis. The overall five-year cumulative graft patency rate of 46% was associated with a 60% limb salvage rate. In cases in which the infrapopliteal graft represented the initial operative procedure, the five-year limb salvage and patency rates (69% and 56%, respectively) were significantly higher (P less than .05) than those achieved with secondary grafts (38% and 22%, respectively). Most limbs (79%) with failed intrapopliteal grafts, without further attempts at reconstruction, required major amputation within six months. The site of the distal anastomosis (anterior tibial, posterior tibial, or peroneal arteries) proved not to be a significant factor in determining long-term limb salvage or graft patency rates. Furthermore, the differences between five-year salvage and patency rates in diabetics (45% and 32%, respectively) and nondiabetics (65% and 53%, respectively) approached but did not reach statistical significance. It is believed these observations support the established but controversial role of infrapopliteal bypass in advanced peripheral occlusive diseases.

Actuarial Analysis↗
PubMed1981

Secondary femoropopliteal reconstruction.

Retrospective analysis of the authors' experience with 109 primary femoropopliteal bypass vein grafts that failed allows description of three distinct modes of failure. Within 30 days of surgery, failure resulted primarily from technical or judgmental errors. The development of stenotic lesions within the vein graft caused a second group of failures during the first year after bypass. The third group most commonly failed due to progression of peripheral atherosclerosis a year or more following original bypass. No correlation was found, however, between the mode of failure and results of secondary femoropopliteal-tibial reconstruction, which yielded an overall 50% five-year cumulative limb salvage rate. The results indicate that this salvage rate can be anticipated regardless of the number of secondary operations required. The highest long-term patency rate was achieved when frequent postoperative follow-up examinations allowed recognition of graft failure prior to total occlusion. Under such circumstances a simple vein patch of stenotic lesions yielded an 85% five-year graft patency. Following actual thrombosis, however, the highest five-year patency rate was achieved when reconstruction was performed using a new vein graft; saphenous vein and arm vein were equally effective. When prosthetic material was used, no secondary graft remained patent beyond three years. Finally, when a proximal or distal portion of the original vein graft proved adequate in caliber following thrombectomy, it could be successfully incorporated in a secondary reconstruction with the expectation of a 50% five-year limb salvage rate. No statistically significant difference was found in salvage rates among each of the patient groups representing the three common modes of graft failure. This finding, coupled with an acceptable 2.5% operative mortality rate, provides justification for an aggressive approach toward secondary femoropopliteal reconstruction.

Arteriosclerosis↗
PubMed1978

Impedance plethysmography: its limitations as a substitute for phlebography.

Impedance plethysmography (IPG) was used to study 132 legs: 100 in normal volunteers not subjected to radiocontrast phlebography, seven in patients whose limbs were phlebographically normal, and 25 proven by phlebography to have deep venous thrombosis (DVT). There were no false positive IPG results when a maximum venous outflow of 0.2% was the discriminant. However, in the 25 legs with thrombosis in calf, popliteal, femoral, and iliac veins, clots were not detected by IPG in 44--51% of legs, depending upon the discriminant. These results, which are in agreement with data reported elsewhere, indicate that it is reasonable to use the IPG method as the sole diagnostic maneuver when the test result is clearly abnormal, but that if the result is not abnormal, a radiocontrast phlebogram is necessary.

Adult↗
PubMed1978

The cost of misadventures in colonic surgery. A model for the analysis of adverse outcomes in standard procedures.

Analysis revealed an impressive number of patients transferred to intensive care at the Peter Bent Brigham Hospital after misadventures in standard medical and surgical procedures. The model explored here is that of colon surgery, a therapy standardized for decades. The courses of sixteen patients were studied, wherein adverse outcomes appeared to have been preventable. Failure to diagnose colonic leakage and failure to provide colostomy (or to do so safely) were the major underlying causes. Nephrotoxic antibiotics and immunosuppression were sometimes in the background. Nine patients died, all with severe sepsis. Multiple organ failure occurred in the majority of cases. The mortality was tenfold, the cost sevenfold, and the length of hospitalization fourfold that expected after uneventful operation. Current interest in cost-benefit analysis should be broadened standard medical and surgical procedures. Litigious potential should not be allowed to impede such analyses.

Adolescent↗
PubMed1978

Muscle perfusion and the healing of below knee amputations.

Muscle pH has been used to assess the perfusion of the muscles at the site of below knee amputation in 20 patients having ischemia at the periphery. The results show that a muscle pH above 7.0 did not correlate with the outcome of amputation but that, when the pH was below 7.00, healing was never achieved.

Amputation, Surgical↗
PubMed1977

Portacaval diversion for severe hypercholesterolemia. Report of a case with measurements of glucose tolerance, insulin, and glucagon levels.

An end-to-side portacaval shunt was performed in a patient with severe coronary arteriosclerosis and type IIa hypercholesterolemia. By one year postoperatively there was a decrease of serum cholesterol concentration of more than 40%. No adverse side effects were noted. Intravenous and oral glucose tolerance tests were performed and were within normal range preoperatively and postoperatively. However, preoperatively, during the oral test, the serum insulin levels exceeded the normal range. In addition, glucagon levels revealed less tendency to suppression during the preoperative oral tests. Psychological testing revealed no abnormalitites, and serum ammonia levels were only slightly elevated.

Adult↗
PubMed1977

Natural history of the leg amputee.

For 173 patients undergoing major leg amputations, the operative mortality was 13 per cent. The ratio of below-knee (BK) to above-knee (AK) amputations was approximately unity. Of the 150 patients who survived amputation, 93 were given prostheses. Amoung the latter group, 76 per cent of the unilateral AK amputees and 90 per cent of the unilateral BK amputees had a successful rehabilitation. For those patients who had to be converted from BK to AK unilateral amputations, 40 per cent experienced successful rehabilitation, and for those who had either bilateral BK or bilateral mixed amputations, 45 per cent were successful. The most common contraindications to granting prostheses were debility and dementia. The mean time interval from first amputation to latest observation was 3.5 years (range, 5 weeks to 13.5 years). At three years 49 per cent of the patients survived and at five years 31 per cent survived. Despite major impediments, satisfactory rehabilitation is accomplished frequently enough to justify optimism for a considerable number of geriatric amputees.

Adult↗
PubMed1977

The reduction of mortality of abdominal aortic aneurysm resection.

The reasons for improvement in mortality after abdominal aortic aneurysmectomy in 144 consecutive patients are assessed. Elective aneurysmectomy carried a mortality of 5.7 percent. The deaths were all attributable to myocardial infarction occurring in patients with known coronary artery disease.

Adult↗
PubMed1977

Surgery and the progression of the occlusive process in patients with peripheral vascular disease.

The angiograms and clinical records of 42 patients with arteriosclerosis obliterans who underwent repeat angiography were analyzed in order to correlate the effects of surgery with progression of the occlusive process in native vessels. Occlusive disease progressed significantly faster in operated limbs (77%) than in nonoperated limbs (44%). When progression occurred, it was more likely to take the form of occlusion in operated limbs (85%) than in nonoperated limbs (61%). Graft closure was associated with a 93% incidence of disease progression, but even limbs with patent grafts had a more rapid progression than the nonoperated limbs (62% vs. 44%). There was a good correlation between the presence of symptoms and the angiographic progression.

Aged↗
PubMed1976

The relationship between muscle surface pH and oxygen transport.

The relationship between muscle surface pH (pHM) and the arterial-venous oxygen content difference (AVO2D) was studied in 4 patients undergoing reconstructive arterial surgery and in 6 patients undergoing acute normovolemic hemodilution. There was a consistent inverse relation between pHM in the ischemic lower extremity and the femoral AVO2D before, during and after aortic clamping. There was also an inverse relation between AVO2D and pHM during hemodilution. These data confirm that pHM is a reliable indicator of tissue perfusion and correlates with the AVO2D.

Adult↗