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Biomedical subjects

G D Grossman

Publications and source records attributed to G D Grossman.

11 recordsLinked to original sources
PubMed1987

Bioenergetic and metabolic response to continuous v intermittent nasoenteric feeding.

Resting thermal energy losses and metabolic balances of N, K, P, Ca, Na, and Mg were compared during continuous and intermittent nasoenteric formula infusion in four healthy men. Each feeding protocol lasted 1 week in a 4-week double crossover experiment. The initial feeding schedule was established randomly. Continuous nasoenteric formula infusion produced no increase in thermal energy losses above the fasting level; energy expenditure fell with sleep to the same extent as with intermittent feeding. Thermal losses were similar during intermittent feeding with the exception of the thermic effect of food that produced an additional average energy loss of 115.7 kcal/d. The total resting and sleeping 24-hour energy expenditure was significantly lower (P less than .01) during continuous formula infusion (means +/- SD for n = 8 balance periods, 1344 +/- 119 kcal) compared to intermittent feeding (1457 +/- 179 kcal). No significant differences in nutrient absorption or balances of N, Na, Ca, and Mg were detected between the two feeding protocols. In contrast, continuous infusion of formula was accompanied by negative balances of K and the cytosolic portion of P; weight balance was slightly negative. Weight, K, and cytosolic P balances were all positive during intermittent feeding (P = NS, less than 0.01, and P less than .05 compared to respective continuous infusion periods). Hence, 1 week of continuous nasogastric formula infusion is associated with similar nutrient absorption, a significant reduction in thermal energy losses, and equivalent protein (N) balance relative to intermittent feeding. Differences in weight balance between the two feeding protocols can be ascribed largely to fluid and mineral shifts. These results suggest that energy requirements are lower during continuous formula infusion by about 100 kcal/d compared to regular meal ingestion.

Adult↗
PubMed1986

Effectiveness of medical necessity guidelines in reducing cost of oxygen therapy.

Concern for the rising costs of respiratory therapy in patient care caused a third party payor to implement reimbursement guidelines for inhospital delivery of oxygen (O2) therapy. While these guidelines are physiologically appropriate, their effectiveness in cost reduction has not been documented. To determine the effect of similar guidelines on the cost of O2 therapy, we prospectively studied 77 noncritically ill patients for whom physicians ordered O2. If pretreatment arterial blood gas determinations had not been ordered, ear oximetry was performed. The cost of O2 therapy to each patient, as based on total patient charges for O2, appliances, delivery, and assessment of oxygenation throughout hospitalization, was computed in three ways: Cost A, actual charges for O2 therapy initiated by physician order; Cost B, projected charges for O2 therapy using physiologic guidelines alone (PaO2 less than 60 mm Hg or SaO2 less than 90 percent); and Cost C, projected charges for O2 therapy using combined physiologic and clinical guidelines (PaO2 less than 60 mm Hg, SaO2 less than 90 percent or clinical record reasonably indicating hypoxemia). Of the 77 patients, 23 (30 percent) met the physiologic guidelines and 48 (62 percent) met the combined physiologic and clinical guidelines. The cost (total patient charges) of O2 therapy can be reduced through implementation of medical necessity guidelines, but physiologic guidelines alone appear more cost effective than combined physiologic and clinical guidelines.

Blood Gas Analysis↗
PubMed1985

The relative gonadal index: an alternative index for quantification of reproductive condition.

Gonadal indices (i.e. GSI = gonadal wt/body wt X 100) commonly are used to quantify reproductive condition in fishes. These indices may be inappropriate with specimens of different sizes, however, for gonadal growth often is allometric. A new gonadal index (relative gonadal index, RGI) was developed to quantify the reproductive condition of animals independent of body size. The RGI is based on the underlying model W = alpha i X S beta i, where W is gonadal weight, S is body size (less gonadal weight if body weight is used), and alpha i and beta i are parameters to be estimated for gonadal developmental stage i. Assuming that a multiplicative lognormal error is appropriate, parameter estimates for alpha i and beta i were obtained by linear least squares regression for the log-transformed model ln(W) = beta i X ln(S) + ln(alpha i), where, in this form, beta i is the slope and ln(alpha i) is the intercept. Only if estimates of beta i do not differ significantly among ovarian developmental stages, as in our case, can a pooled estimate of beta be used to obtain the relative gonadal index, RGI = alpha i = W/S beta. Applicability of the RGI was tested using ovaries of three ecologically distinct fish species. The RGI was found to be more appropriate than the gonosomatic index for all three species.

Animals↗
PubMed1985

Human energy requirements: overestimation by widely used prediction equation.

Basal energy expenditure accounts for a large component of energy losses, and a clinical estimate of this form of thermogenesis is usually derived from a prediction equation. The most widely used prediction equation was developed in 1919 by Harris and Benedict. The energy requirements of healthy and diseased individuals are often estimated from application of this formula. Using a direct gradient-layer calorimeter and two different indirect calorimeters, our two centers found that the Harris-Benedict equation overestimated basal energy requirements by 10 to 15% (X +/- SD, 12.3 +/- 11%) in 201 studies of healthy men and women. These results raise questions regarding the accuracy of predicting an individual's energy requirements.

Adolescent↗
PubMed1984

Respiratory, cardiovascular, and metabolic effects of enteral hyperalimentation: influence of formula dose and composition.

Respiratory, cardiovascular, and metabolic changes were monitored during balance studies in undernourished patients receiving continuous enteral formula feeding. The nutrient solutions, either high carbohydrate (83% of kcal) or high fat (50% of kcal), were administered at doses ranging from 2.7 to 6.0 X 10(-2) kcal X kg fat free body mass-1 X min-1. For both formulas, the observed physiological changes between fasting and the lower rates of energy infusion (ie, maintenance-slow growth) were either zero or relatively small. As formula dose was advanced into the rapid repletional range, physiological changes were more pronounced; there were linear increases in oxygen consumption, carbon dioxide production, minute ventilation, heat production, heat release, nitrogen balance, and change in heart rate from the base-line (all p less than 0.05 for both formulas). The rate at which carbon dioxide production, minute ventilation, and heat production increased with advancing energy infusion rate was also greater for the high carbohydrate formula relative to the high fat formula (p less than 0.02, less than 0.07, and less than 0.06, respectively). The physiological changes caused by continuous intragastric feeding are therefore a function of formula infusion rate and composition. Knowledge of these changes can be applied to patients treated for semistarvation who suffer respiratory or cardiac insufficiency.

Adult↗
PubMed1984

Uptake of antibiotics by human alveolar macrophages.

To provide additional criteria for therapy of pulmonary infections caused by facultative intracellular bacteria, we studied the uptake of 12 antibiotics by alveolar macrophages (AM) obtained from healthy, young volunteers by bronchoalveolar lavage. These human AM were incubated with radiolabeled antibiotics for periods as long as 2 h. Entry of antimicrobials into the cells was determined by means of a velocity-gradient centrifugation technique. Antibiotic uptake was expressed as the ratio of the cellular to the extracellular drug concentration (C/E). Penicillin G, cefamandole, and gentamicin were taken up poorly by human AM (C/E = 0.5 to 0.8). Isoniazid achieved a cellular concentration similar to the extracellular level of the drug (C/E = 0.9). Chloramphenicol, rifampin, tetracycline, and lincomycin, drugs that are lipid-soluble, were concentrated several-fold by AM (C/E = 2 to 5). The remaining antibiotics tested, clindamycin, erythromycin, erythromycin propionate, and ethambutol, were markedly concentrated by AM (C/E = 9 to 23). Accumulation of clindamycin (C/E = 23) was a rapid, active, energy-requiring process, which appeared to be dependent upon mitochondrial oxidative metabolism. The ability of the tested antimicrobial agents to enter human AM correlates well with the efficacy of these drugs in treatment of certain intracellular pulmonary infections.

Anti-Bacterial Agents↗
PubMed1981

Pulmonary function test criteria for operability and pulmonary resection.

Pulmonary function criteria for pulmonary resection, other than pneumonectomy, have not been previously described. A series of 500 consecutive pulmonary resections to which specific pulmonary function criteria were applied in determining the amount and the extent of feasible resection of the lung are presented. By application of these criteria, an accurate assessment of the type and extent of pulmonary resection a patient can tolerate without expected mortality can be made. With utilization of these criteria, the operative mortality for segmental resection was 0.2 per cent; for lobectomy, zero per cent, and for pneumonectomy, 4.4 per cent.

Adolescent↗
PubMed1978

Bronchoscopy in the community hospital.

A new Pulmonary Medicine-Thoracic Surgery service was established in a community hospital in July 1974. This report details the experience of 409 bronchoscopies performed from July 1, 1974 through Dec 31, 1976. There were no deaths and four complications--one aspiration and three pneumothoraces resulting from transbronchial lung biopsy. Final diagnoses for which bronchoscopy was done were as follows: cancer--141; infectious disease--97; interstitial disease--33; obstructive lung disease--58; hemoptysis--35; miscellaneous--45. In the cancer group, a cytohistologic diagnosis was made in 82 patients by bronchoscopy alone, 31 additional diagnoses were made by scalene node biopsy or mediastinoscopy, and the remainder by surgical exploration and/or resection. In 268 patients with benign disease, bronchoscopy established the diagnosis in 87% of the cases. Pulmonary Medicine tended not to repeat nondiagnostic bronchoscopy but rather to refer immediately for a definitive surgical procedure. Thoracic Surgery tended not to reduplicate bronchoscopy for the purpose of "confirmation." A conjoint medical-surgical approach to bronchial disease, at the community level and based on a mutual understanding of capability and limitation, is feasible, productive, and economical.

Bronchoscopy↗
PubMedDate not supplied

A simple and accurate indirect calorimetry system for assessment of resting energy expenditure.

An indirect calorimetry system was assembled from three readily available major components: a digital pneumotachograph, an oxygen analyzer, and a carbon dioxide analyzer. A one-way valve, face mask, and meteorological balloon completed the system. Accuracy was assessed by comparison to direct calorimetry in hospitalized patients undergoing enteral hyperalimentation. Each subject was on continuous infusion of formula during a 7-day metabolic balance. Direct and indirect calorimetry was performed over the last 4 days of the balance. The overall agreement between the two methods was within 1%. A simple and inexpensive calorimetry system can therefore be assembled to provide an accurate measure of resting energy expenditure.

Adult↗