Biomedical subjects
C W Van Way
Publications and source records attributed to C W Van Way.
Caloric and nitrogen balances as predictors of nutritional outcome in patients with burns.
Measurement of energy expenditure with indirect calorimetry allows determination of caloric balance. The present study was done to determine the predictive value of caloric and nitrogen balances for nutritional outcome. Energy expenditure was obtained weekly and interpolated between measurements for daily caloric balance. Nitrogen balance was obtained weekly. Because nitrogen output fluctuated, interpolation of daily values was not possible. Nutritional outcome was defined by whether body weight was lost or maintained and by levels of visceral proteins (albumin, prealbumin, and transferrin). The study group included 12 patients with 7% to 82.5% total body surface area burns. Eleven patients survived their burn injuries, and one died of congestive heart failure at 38 days, after her burn wounds had healed. Nine patients had good nutritional outcomes (group 1) and three had poor nutritional outcomes (group 2) (including the one who died). Nitrogen balance was 1.3 +/- 1.0 gm/day in group 1 and 4.5 +/- 1.7 gm/day in group 2 (mean +/- SEM; p > 0.10). Caloric balance was 515 +/- 130 kcal/day in group 1 and -667 +/- 140 in group 2 (p < 0.001). Caloric balance was significantly different between the two groups, whereas nitrogen balance was not. Caloric intake correlated positively with nitrogen intake (r = 0.92). Nitrogen intake was 16% of total caloric intake. Nitrogen intake from blood products was appreciable and averaged 15% of total nitrogen intake (range, 0% to 47%); 11.3 +/- 1.6 gm/day in group 1 and 14.8 +/- 3 gm/day in group 2 (p > 0.10).(ABSTRACT TRUNCATED AT 250 WORDS)
Nitrogen balance and electrolyte requirements in intralipid-based hyperalimentation.
The present study was directed at determining whether or not a relatively low-calorie regimen in which 40 to 50% of the calories are provided as fat will produce positive nitrogen balance in most patients, and at establishing the electrolyte requirements for such a regimen. Clearly, the recommended regimen is successful in promoting nitrogen balance and provides adequate electrolytes. Further experience will be necessary to determine the place of intravenous fat emulsions in the clinical practice of total parenteral nutrition.
Factors influencing nutritional assessment in abdominal trauma patients.
Previous work has shown that an abdominal trauma index (ATI) based on anatomic severity of injury reliably predicts complications following abdominal trauma, whereas the Prognostic Nutritional Index (PNI) does not. This study was undertaken to reconcile the disparity between the PNI and ATI as predictors of postoperative morbidity and mortality. Twenty-four patients undergoing immediate laparotomy following acute abdominal trauma were evaluated. Their mean age was 32.8 years (range 18-59 years); 18 were men. All patients underwent nutritional assessment within 12 hours of surgery. A statistical comparison of blood replacement, operating time, ATI, and PNI was performed. The mean PNI was 51 and mean blood replacement was 12.5 units. Using linear regression the PNI and amount of blood replacement correlated significantly (r = 0..44, p less than 0.05). Operating time and ATI did not correlate with PNI. In conclusion, the PNI was more strongly influenced by blood loss than severity of intraperitoneal injury. For this reason it is relatively ineffective in predicting complications following trauma.
Variability of the Harris-Benedict equation in recently published textbooks.
The Harris-Benedict equation, as cited in a selection of textbooks of medicine, surgery, and nutrition, was compared with the original monograph published by the Carnegie Foundation. A significant amount of variation was found in published versions of this equation. Of 24 published versions, eight were sufficiently variant to produce errors of 7% to 55% in calculations of nutrition requirements. The error is usually in the constant term for one of the two Harris-Benedict equations. Either the constant term for men is increased to a value approximately the same as for women, or the constant term for women is reduced to be approximately equal to that for men. The primary reason appears to be the lack of availability in medical libraries of the original Carnegie Foundation publication by Harris and Benedict.
Renal venous renin activity in renovascular hypertension.
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Thermokinetics of cold cardioplegic arrest.
This study was designed to test the hypothesis that the rapidity with which the heart rewarms following cold cardioplegic arrest depends upon the technique of cannulation. In dogs, temperatures were monitored at multiple myocardial sites during rewarming, using four different cannulation techniques: caval cannulation with total bypass, caval cannulation with partial bypass, atrioventricular cannulation, and atrial cannulation. A mathematical model was constructed to facilitate analysis of the data, assuming that the rewarming process can be described by first order kinetics. Using this model, the half time of rewarming was defined as the time required for the myocardium to rewarm halfway from initial temperature to core temperature. Analyzing the several cannulation techniques in terms of the half time of rewarming, several conclusions were drawn: myocardial temperature distribution is non-homogeneous, rewarming is relatively rapid, partial bypass produces more rapid rewarming than total bypass, atrioventricular cannulation produces more rapid rewarming than either caval or atrial cannulation, and the principle routes of rewarming were from the posterior parieties and from blood entering the right side of the heart during partial bypass.