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Biomedical subjects

A P Robin

Publications and source records attributed to A P Robin.

At least 19 recordsLinked to original sources
PubMed1991

Absorbable mesh splenorrhaphy for severe splenic injuries: functional studies in an animal model and an additional patient series.

Polyglycolic acid mesh has been introduced as a method of controlling hemorrhage in severely damaged spleens. This study examines the effect of splenic wrapping on the immune function of the spleen, and also on its ability to control splenic bleeding in trauma patients. Thirty purebred beagle dogs were divided into three groups and subjected to sham operation (Group 1), splenectomy (Group 2), and splenic wrap (Group 3). Immunologic studies showed no difference between the wrapped group (Group 3) and those with their spleens intact (Group 1) in the induction of specific antibody-producing lymphocytes in splenic tissue after the injection of attenuated Pneumococci. All splenic injuries treated at Cook County Hospital between January 1985 and May 1988 were retrospectively analyzed. Of 60 patients with splenic injuries, 14 underwent mesh splenorrhaphy without mortality or serious complications. This study demonstrates that the immune function of spleen is preserved following mesh splenorrhapy, and that this technique can be used in a clinical setting with safe and efficacious results.

Absorption↗
PubMed1991

Introduction of bias in residency-candidate interviews.

We have developed, as part of our resident applicant ranking process, a computerized weighted scoring system incorporating, among other variables, the interview score (IS). This study was undertaken to test the IS as a dependent variable when the applicant file is available during the interview. Over a 3-year period, each of two faculty members interviewed 133 candidates in a "blinded" fashion (file unavailable) or 290 candidates with an "open" file. The mean discrepancy between paired interviewers (1 to 10 scale) was 1.34 +/- 0.10 for the blinded group versus 0.93 +/- 0.06 for the open group (p less than 0.001). Individual and multiple regression analysis were used to test the IS as a dependent variable in the open group, with the blinded group as a control. In each instance (except clerkship grades), the IS correlated more closely with other parameters (p less than 0.05) in the open group. Correlation coefficients were 0.27 (blinded) and 0.64 (open) for weighted scores combining all parameters (p less than 0.001) and 0.39 (blinded) and 0.65 (open) for multiple linear regression analysis (p less than 0.001). We conclude that the IS is significantly influenced if other objective variables are at hand, thus deflating the actual weight of the interview. To accurately quantify the value of the interview, a correction factor must be applied, or, more appropriately, the interview must be conducted blindly.

Academic Medical Centers↗
PubMed1989

Fatty acid kinetics in man during chronic and acute illness.

Eight nutritionally depleted and five injured patients were studied prior to and during total parenteral nutrition (TPN). Five additional injured patients were studied at intervals while receiving only 5% dextrose. Fatty acid kinetics and oxidation were determined using an infusion of [1-14C]palmitate. Net substrate oxidation was calculated by indirect calorimetry. During TPN, resting energy expenditure rose from 109 to 119% and from 89 to 103% of predicted in injured and depleted patients, respectively. Free fatty acid (FFA) flux was unaffected, FFA oxidation and net fat oxidation (NFO) decreased by 60%. However NFO began higher in injured subjects (20.7 +/- 2.8 vs 14.6 +/- 0.9 kcal/kg/day, P less than 0.05) and remained higher during TPN (8.3 +/- 1.2 vs 5.6 +/- 0.9 kcal/kg/day, P less than 0.05). The proportion of NFO derived from immediate oxidation of circulating FFA was approximately 35%. The results indicate that, with glucose-based TPN, there is a discrepancy between suppression of FFA production and oxidation. We further conclude that sources of fatty acid which are not in rapid equilibrium with circulating plasma FFA contribute substantially to whole body fat oxidation.

Acute Disease↗
PubMed1989

Measurement of fatty acid oxidation: validation of isotopic equilibrium extrapolation.

Measurement of whole body substrate oxidation requires prolonged isotope infusion to attain plateau specific activity (SA) of expired CO2. We have investigated in 13 hospitalized patients a technique whereby plateau 14CO2 SA is extrapolated using computer curve fitting based upon the early exponential rise. A primed-constant infusion of albumin-bound 1-14C-palmitate was continued for 260 minutes with isotope priming of the secondary bicarbonate pool at 70 minutes. Plasma free fatty acid (FFA) SA reached steady state by 40 minutes and was 91% +/- 4% (SE) of values obtained at 190 to 260 minutes. At 70 minutes 14CO2 SA reached only 44% +/- 1% of the 190 to 260 minute values, which were consistently at plateau. The predicted steady state 14CO2 SA from the 40 to 70 minute curves and the FFA oxidation rates calculated from those values were 94% +/- 2% and 102% +/- 4%, respectively, of values measured at steady state (190 to 260 minutes). The relationship between predicted and measured values approximated the line of identity for 14CO2 SA (y = 0.90x + 0.14, r = .98, P less than .001) and FFA oxidation (y = 1.02x, r = .98, P less than .001). The results suggest that FFA oxidation can be accurately calculated using a short infusion of labeled FFA without bicarbonate pool priming, thus avoiding overpriming or underpriming and possibly allowing multiple studies and diminished radioisotope exposure.

Adult↗
PubMed1989

The effect of urban trauma system hospital bypass on prehospital transport times and Level 1 trauma patient survival.

We studied the influence of hospital bypass on prehospital times and Level 1 trauma patient survival. During the nine-month study period, 251 Level 1 trauma patients were transported to the Cook County Hospital trauma unit by Chicago Fire Department (CFD) paramedics. The prehospital times and survival rates in the 203 (81%) patients who arrived with vital signs were analyzed. In this group, 64 (32%) had a hospital Trauma Score (TS) of 12 or less, 74 (39%) had at least one Abbreviated Injury Score (AIS) of 4 or more, and 58 (30%) had an Injury Severity Score (ISS) of more than 20. There were 66 (32%) directly transported patients and 137 (68%) patients who required hospital bypass. The time from CFD contact (by 911) to trauma center arrival (total run time) was on the average three minutes longer in the bypass group than in the direct group (36 +/- 11 vs 33 +/- 10 minutes, P less than .05). The travel time from the scene to the hospital (transport time) also was three minutes longer in the bypass group (7 +/- 3 vs 4 +/- 2 minutes, P less than .005). The need for bypass did not significantly influence survival. Survival was 86% in the bypass group and 85% in the direct group. The elapsed time between the injury and CFD contact (delay time) averaged 27 +/- 26 minutes and contributed 43% to the 63-minute mean overall time from the injury event to arrival at the trauma center. Total run time in directly transported patients accounted for 52% of the mean overall prehospital time.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Selective management of anterior abdominal stab wounds.

A policy of selective management of anterior abdominal stab wounds was evaluated in 333 consecutive patients. Laparotomy was performed based upon initial clinical assessment in 165 patients. There were six deaths (3.6%), major complications in 23 patients (14%), and 28 negative laparotomies (17%). Eighteen patients developed indications for laparotomy after 10.7 +/- 2.2 hours of observation. There were no deaths, major complications in two patients (11%), and four negative laparotomies (22%). One hundred fifty patients were observed and discharged after 1.8 +/- 0.1 days. Sensitivity, specificity, and positive and negative predictive values for initial clinical evaluation were 91%, 85%, 92%, and 83%, respectively. Length of hospitalization in the initially operated and in the delayed group was 9.5 +/- 0.6 and 10.6 +/- 2.6 days (NS), respectively. Most serious intra-abdominal injuries will declare themselves on initial clinical assessment. The remainder are less severe injuries and these patients can be safely observed without undue sequelae due to delay. The use of clinical assessment alone to prompt laparotomy is also cost effective based on analysis of hospital days for initial illness. No procedures are necessary to define penetration.

Abdominal Injuries↗
PubMed1988

Peritoneal lavage in penetrating thoraco-abdominal trauma.

Forty-five consecutive patients with penetrating thoraco-abdominal trauma underwent surgical exploration to evaluate the ability of peritoneal lavage to detect peritoneal penetration. Eight patients fulfilled standard criteria for operation and did not undergo lavage. The remaining 37 patients underwent diagnostic peritoneal lavage using a closed technique before exploratory laparotomy. Using 10,000 RBC/mm3 as our previously established criterion for peritoneal penetration, there were seven true positive, one false positive, 28 true negative, and one false negative lavage for an overall accuracy of 94.6% with 87.5% sensitivity and 96.6% specificity as determined by subsequent laparotomy. While 33% of this patient cohort were found to have significant injuries (four had isolated diaphragmatic injuries, all detected by peritoneal lavage), 67% were subjected to negative surgical exploration, as accurately predicted by peritoneal lavage. Negative laparotomy carried a 10.7% operative morbidity. Based on these data we advocate diagnostic peritoneal lavage in patients with thoraco-abdominal penetrating trauma who otherwise lack operative indications.

Abdominal Injuries↗
PubMed1988

The use of absorbable mesh in splenic trauma.

Previous reports from this hospital documented a splenic preservation rate of 50% (18/36) in adults after blunt and penetrating trauma. Recently (January through December 1984), use of an absorbable mesh helped to attain a 67% (22/33) salvage rate. The mesh is applied in such a fashion that it acts by tamponade. It proved useful in patients with bleeding from a large surface area or from deep parenchymal injuries, even those extending into the hilum. No deaths occurred in the splenic salvage patients. There was no difference in postoperative complications among the splenectomy, conventional splenorraphy, or mesh wrap splenorraphy groups. However, workup of persistent postoperative fevers in two splenic wrap patients revealed perisplenic fluid collections on CT scan. Aspiration yielded sterile fluid. Possible cause and effect relationship is being studied in the dog lab. We conclude that splenic wrapping is both a safe and efficacious method of splenic preservation.

Adolescent↗
PubMed1987

A new method of rapid fluid resuscitation during thoracotomy performed in the emergency room.

A new technique for inserting and securing large bore intravenous lines directly into the right atrium, to be used in patients requiring a thoracotomy in the emergency room, is described herein. A plastic clip is attached to the edge of the atrial appendage and holds a large catheter in place. We have used this new technique successfully at the Cook County Hospital Trauma Unit and have encountered no complications to date.

Catheters, Indwelling↗
PubMed1986

Fibronectin depletion and microaggregate clearance following trauma.

Ninety-seven traumatized patients had blood samples taken immediately upon admission before any resuscitation. Microaggregate (MA) formation was measured by the screen filtration pressure (SFP) technique. Plasma fibronectin levels (Fn) were measured by immunoturbimetric assay. An Injury Severity Score (ISS) was calculated for each patient. The results show a highly significant correlation between severity of trauma, amount of MA formation, and amount of Fn depletion. We conclude that the highly significant correlation between MA formation and Fn depletion following trauma suggests a role for the reticuloendothelial system (RES) in the clearance of MA that form following trauma. Further, enhancement of RES clearance of MA may be possible by purified Fn or cryoprecipitate administration early in the treatment of trauma patients, thereby preventing the adverse sequelae of end organ MA deposition.

Animals↗
PubMed1986

Basic principles of intravenous nutritional support.

Parenteral nutrition has been one of the major advances in clinical medicine in the 20th century. By maintaining or re-establishing optimal nutritional status, one can help to ensure an optimal response to appropriate medical or surgical management of the primary disease process. In order to plan an appropriate nutritional regimen, the health-care provider must be equipped to pursue the following thought processes: Understand the consequences of malnutrition. Identify the patient who may benefit from nutritional support. Assess the underlying clinical and metabolic setting. Assess the current nutritional status. Formulate a goal of nutritional intervention--a therapeutic plan. Determine the route and method of administration; the quantity and source of energy and nitrogen; and requirements for fluid, electrolytes, minerals, vitamins, and trace elements. Monitor the patient. Evaluate the efficacy and determine the duration of therapy.

Catheterization↗
PubMed1984

Measurement of glycerol turnover by infusion of nonisotopic glycerol in normal and injured subjects.

A new technique for measuring glycerol turnover in human subjects is presented using a staged infusion of unlabeled glycerol. A total of 105 measurements was made in normal subjects and postoperative or acutely ill patients. The relation between glycerol turnover rate (R tau) and concentration (C) (R tau = 31 + 2.07C) from 80 staged infusion measurements in 21 normal subjects did not differ significantly from observations of others made by isotope dilution. In 11 patients, glycerol turnover was also measured by dilution of isotopic glycerol. Mean values did not differ significantly between the two methods. The average difference, regardless of sign, for individual values was 17%. This agreement tends to validate the assumptions of both methods. Advantages of the staged infusion method are that it is quicker and easier to perform and does not entail a risk due to administration of radioactive materials. Evidence obtained in this study from a three-stage procedure indicates that satisfactory information may be obtained from a two-stage infusion at successive rates of 250 and 600 mumol/min for 70 min each, with a prime of 2 mmol given as a bolus at the start of each stage.

Adult↗
PubMed1984

Influence of parenteral carbohydrate on fat oxidation in surgical patients.

The administration of parenteral carbohydrate to nutritionally depleted patients in amounts approximating energy expenditure will markedly suppress fat oxidation. If the amount of carbohydrate is increased, net lipogenesis will occur. In contrast, it has been reported that in acutely ill, hypermetabolic patients net fat oxidation continued during the administration of glucose in quantities that exceeded energy requirements. This investigation was undertaken in an attempt to determine to what extent the latter response is due to persistent oxidation of endogenous plasma free fatty acids (FFAs) or stores of lipid in tissue. In this study, carbohydrate intake above energy equilibrium resulted in a 29% increase in CO2 production, a 2% increase in O2 consumption, and an increase in respiratory quotient (RQ) from 0.77 to 0.97 in nutritionally depleted patients. Injured and infected patients displayed a 44% increase in CO2 production and a 15% increase in O2 consumption, while the RQ increased only to 0.9. An isotopic palmitate infusion was used to measure FFA oxidation during parenteral nutrition with variable amounts of carbohydrate. Simultaneous estimates of net fat oxidation were made by indirect calorimetry. At low carbohydrate intakes, oxidation of plasma FFAs accounted for 50% of net fat oxidation in both groups of patients. Suppression of FFA oxidation was greater in the nutritionally depleted patients than in the acutely ill group at intermediate and at high carbohydrate intakes. We conclude that the continued net fat oxidation seen in acutely ill patients receiving high carbohydrate intakes is at least partially due to continuing plasma FFA oxidation. Tissue fat stores that are not in rapid equilibrium with plasma FFAs make a substantial contribution to net fat oxidation.

Energy Metabolism↗
PubMed1983

Free fatty acid mobilization and oxidation during total parenteral nutrition in trauma and infection.

Free fatty acid (FFA) metabolism was studied in 18 traumatized and/or septic patients. Each patient was studied while receiving 5% dextrose (D5W) and after 4 to 7 days of total parenteral nutrition (TPN). Nonprotein energy during TPN was given either entirely as glucose (Glucose System) or as equal portions of intravenous fat and glucose (Lipid System). Plasma FFA concentrations were in the normal range on D5W and decreased markedly with TPN. FFA turnover was higher than normal on D5W and did not decrease significantly with TPN. The poor correlation between these two variables emphasizes the need to perform kinetic studies to characterize FFA metabolism in trauma and sepsis. Plasma FFA oxidation and net whole body fat oxidation measured by indirect calorimetry were in the normal range on D5W, 35 and 82%, respectively, of resting energy expenditure (REE). With a glucose intake averaging 108% of REE, plasma FFA oxidation and net fat oxidation decreased to 17 and 13%, respectively, of REE. Nonprotein RQ increased only to 0.94 despite administration of glucose in excess of REE, indicating an abnormal persistence of fat oxidation. During D5W administration, plasma FFA accounted for less than one half of total fat oxidation, indicating that unlabeled fat, such as tissue or plasma triglycerides not in rapid equilibrium with plasma FFA, accounted for the bulk of fat oxidation. Glucagon concentrations which were high on D5W did not decrease significantly with TPN. Insulin concentrations were normal on D5W and increased in response to TPN. The abnormal hormonal milieu may account for much of the abnormal fat metabolism. Administration of large amounts of glucose decreased FFA oxidation much more than FFA mobilization. Thus, the infused glucose acts to increase the rate of "futile cycling" of FFA in these acutely ill patients.

Adolescent↗
PubMed1983

Nitrogen balance during total parenteral nutrition: glucose vs. fat.

Nitrogen balance and energy expenditure were measured in 18 traumatized and/or septic patients and five depleted patients during different dietary conditions. Total parenteral nutrition (TPN) was given with nonprotein energy entirely as hypertonic glucose solutions (glucose system) or as half glucose-half intravenous fat emulsion (lipid system). In acutely ill patients, the change from 5% dextrose to TPN resulted in a prompt improvement of nitrogen balance to maintenance levels. There were no significant differences between patients given the glucose or lipid system. The five depleted patients were given the lipid and glucose systems alternately for a total of 19 one-week periods. A highly positive N balance, 80 mg N/kg . day, was attained on both diets. There was no significant difference between diets and no period of adaptation after switching from one diet to the other. On comparable intravenous diets, the acutely ill patients had higher plasma concentrations of glucose, glycerol, triglycerides, insulin, and glucagon than did the depleted patients. The study shows that the nitrogen-sparing effects of the lipid and the glucose systems are similar in moderately traumatized or infected as well as in malnourished patients. Factors other than nitrogen balance are of greater importance when choosing between the lipid and the glucose system for intravenous support.

Adolescent↗
PubMed1982

Metabolic utilization of intravenous fat emulsion during total parenteral nutrition.

The effect of nutritional therapy on the utilization of an intravenous fat emulsion was studied in patients with injury, infection, and nutritional depletion using I-14C-trioleate labeled Intralipid. The plasma fractional removal rate and 14C-Intralipid oxidation rate was 55% ad 25% higher, respectively, in patients following trauma and during periods of infection receiving 5% dextrose than in healthy control subjects. Total parenteral nutrition (TPN) was administered as either 1) nonprotein calories given as glucose (Glucose System) or 2) equal proportions of glucose and intravenous fat emulsion (Lipid System). In comparison to TPN with the Lipid System, administration using the Glucose System resulted in higher plasma clearance rates and lower oxidation rates in both acutely ill and depleted patients. There was no correlation between the rates of plasma removal and oxidation of the intravenous fat emulsion (r = -0.04; NS) indicating that the removal of exogenous fat from plasma cannot be used as an indicator of oxidation. A negative linear relationship was seen between the oxidation rate of intravenous fat and carbohydrate intake (r = -0.92; p less than 0.001). Glucose intakes exceeding energy expenditure did not totally inhibit oxidation of the fat emulsion. The oxidation rate of 14C-Intralipid was linearly related to net whole body fat oxidation calculated using indirect calorimetry (r = -0.90; p less than 0.001) suggesting that the fat emulsion was oxidized in a similar manner to endogenous lipids. This study suggests that intravenous fat emulsions are utilized as an energy substrate in patients with major injury, infection or nutritional depletion. This observation, along with a relative unresponsiveness to glucose in surgical patients suggests that fat emulsions may be useful as a calorie source in patients receiving parenteral nutrition.

Adolescent↗
PubMed1981

Influence of total parenteral nutrition on tissue lipoprotein lipase activity during chronic and acute illness.

This study examines the influence of total parenteral nutrition (TPN) compared with 5% dextrose (D5) infusion on skeletal muscle and adipose tissue lipoprotein lipase (LPL) activity in nutritionally depleted, injured and infected patients. The plasma concentrations of glucose, free fatty acid (FFA), triglyceride and insulin were also measured. During TPN, nutritionally depleted subjects showed an increase in adipose tissue LPL activity, "fat cell size," and plasma insulin concentration. Skeletal muscle LPL activity and plasma FFA concentration decreased. In comparison, trauma patients showed a less marked rise in adipose tissue LPL activity and skeletal muscle LPL activity increased. Infected patients had a much smaller rise in adipose tissue LPL activity than either of the other groups, and muscle activity rose. The depleted and injured patients showed a linear relationship between adipose tissue LPL activity and plasma insulin concentration and an inverse hyperbolic relationship between adipose tissue LPL activity and plasma FFA concentration.

Acute Disease↗