Nourishing the obese patient.

Obese patients are frequently encountered in hospitals. This is not unexpected given the fact that obesity currently constitutes a worldwide public health epidemic. The clinical indications for nutritional support and route of nutrition support selected should be similar in obese and normal weight patients. Determining nutritional requirements by conventional methods and formulas are often inaccurate in this population. For this reason, direct measurement of energy needs using indirect calorimetry when available has become the preferred method. A strategy employing hypocaloric nutrition support will be presented and discussed.

A health status assessment of the impact of weight loss following Roux-en-Y gastric bypass for clinically severe obesity.

BACKGROUND: The field of "medical outcomes" emphasizes effects of medical treatments on quality of life as seen from the patient's perspective. The increasing incidence of obesity has had tremendous impact on the physical, psychological, social, and economic health of our nation with important longterm implications for the development of future social and health care policies. This study evaluated the effects of clinically severe obesity on overall health status measured in a standardized fashion and the impact of durable weight loss achieved through surgical intervention. STUDY DESIGN: Patients scheduled for Roux-en-Y gastric bypass for treatment of obesity were prospectively evaluated. At the preoperative visit, each patient completed Short Form 36 (SF-36). Postoperatively, patients were again asked to complete SF-36, in person or through a telephone interview at an interim point (3 to 12 months) and after their weight had reached a plateau (>18 months). RESULTS: The mean body mass index (BMI) was 51+/-10 kg/m2 preoperatively (range 38 to 85 kg/m2). Mean BMI was 45+/-10 kg/m2 (range 33 to 78 kg/m2) at the interim point and 35+/-8 kg/m2 (range 28 to 55 kg/m2) at plateau. The weight change for the group was from 306+/-8 lb (138+/-4 kg) preoperatively to 211+/-55 lb (96+/-25 kg) at the plateau, with the average percent of excess body weight lost being 63+/-23% at the plateau. Preoperatively, patients with clinically severe obesity scored significantly lower than the normal population in all areas except Role Activities (Emotional Factors). At the plateau period, patients demonstrated significant improvement in limitations in all areas compared with preoperative values and scores were the same as (Physical Activities, Role Activities [Physical Factors], General Mental Health, General Health Perceptions), or significantly better than (Social Functioning, Role Activities [Emotional Factors], Bodily Pain, Vitality), the national "normal" population. CONCLUSION: Clinically severe obesity is a chronic disabling disease that results in significantly decreased health status in seven of the eight areas measured by SF-36. This disability resolves with successful weight reduction. In some areas, function even surpasses the national "normal" population. Surgical treatment of clinically severe obesity has a profoundly positive impact on patients' perception of their health status.

Comparison of indirect calorimetry, the Fick method, and prediction equations in estimating the energy requirements of critically ill patients.

BACKGROUND: Accurate measurement of resting energy expenditure (REE) is helpful in determining the energy needs of critically ill patients requiring nutritional support. Currently, the most accurate clinical tool used to measure REE is indirect calorimetry, which is expensive, requires trained personnel, and has significant error at higher inspired oxygen concentrations. OBJECTIVE: The purpose of this study was to compare REE measured by indirect calorimetry with REE calculated by using the Fick method and prediction equations by Harris-Benedict, Ireton-Jones, Fusco, and Frankenfield. DESIGN: REEs of 36 patients [12 men and 24 women, mean age 58+/-22 y and mean Acute Physiology and Chronic Health Evaluation II score 22+/-8] in a hospital intensive care unit and receiving mechanical ventilation and total parenteral nutrition (TPN) were measured for > or = 15 min by using indirect calorimetry and compared with REEs calculated from a mean of 2 sets of hemodynamic measurements taken during the metabolic testing period with an oximetric pulmonary artery catheter. RESULTS: Mean REE by indirect calorimetry was 8381+/-1940 kJ/d and correlated poorly with the other methods tested (r = 0.057-0.154). This correlation did not improve after adjusting for changes in respiratory quotient (r2 = 0.28). CONCLUSIONS: These data do not support previous findings showing a strong correlation between REE determined by the Fick method and other prediction equations and indirect calorimetry. In critically ill patients receiving TPN, indirect calorimetry, if available, remains the most appropriate clinical tool for accurate measurement of REE.

Changes in measured resting energy expenditure after Roux-en-Y gastric bypass for clinically severe obesity are not related to bypass limb-length.

BACKGROUND: Roux-en-Y gastric bypass (RYGB) for clinically severe obesity (CSO) results in a 'paradoxical' response of the measured resting energy expenditure (MREE) in which the MREE remains within the predicted range based upon the Harris-Benedict (HB) equation, despite a significant decrease in caloric intake to 500-1000 kcal/day. The mechanism for this response is unknown. A study was undertaken to determine whether the changes in MREE after RYGB are related to limb-length of the gastric bypass. METHODS: A prospective clinical trial of varying limb-lengths based on body mass index (BMI) in patients having RYGB for CSO. The records of patients who underwent RYGB for CSO and had MREE measured at baseline, 6 months and 12 months postoperation were reviewed. MREE was performed using a Med Graphics CCM system after an overnight fast or at least 4 hours after a light meal, and a 30 minute rest in a supine position in a neutral environment, on the same day of the week between the hours of 10 a.m. and 4 p.m. Patients were selected for RYGB in accordance with NIH recommendations. RYGB was performed in a standardized fashion with the Roux limb-length varied as follows: (A) BMI < or = 51 kg/m2 - 75 cm limb (n = 20); (B) BMI < or = 51 kg/m2 - 150 cm limb (n = 16); (C) BMI > or = 51 kg/m2 - 150 cm limb (n = 18); or (D) BMI > or = 51 kg/m2 - 250 cm limb (n = 6). RESULTS: Data from 60 patients (nine male, 51 female; mean age 39 years; mean baseline BMI 51.5 +/- 10 kg/m2; mean baseline weight 145 +/- 32 kg) were analyzed. There were no significant differences in MREE or percentage HB-predicted energy expenditure between the groups. CONCLUSIONS: These data suggest that the observed changes in MREE following RYGB for CSO are not related to the limb-length of the bypass.

Effects of low-dose dopamine on urine output in oliguric, critically ill, renal transplant patients.

UNLABELLED: Low-dose dopamine (LD-DA) has been used extensively to increase urine output (UO) in critically ill patients. These effects have recently been documented in patients with normal and mildly abnormal renal function. The purpose of this study was to quantitate the effects of LD-DA on UO and urineNa (UNa) excretion in renal transplant (RT) patients, and thereby evaluate the effects of LD-DA on the denervated kidney. METHODS: Five RT patients and 7 non-transplant controls, hospitalized in the surgical intensive care unit (SICU), with serum creatinine (serum Cr) < 2 mg/dL who were oliguric (UO < 0.5 mL/kg/h), received LD-DA (2.5 micrograms/kg/min). None received other diuretics within 12 h, and all had pulmonary artery occlusion pressure (PAOP) > 10 mmHg and CI > 3.0 L/min/m2. UO was measured hourly and averaged for 2 h pre and 6 h during LD-DA. All data are mean +/- SD. RESULTS: APACHE II (14 +/- 4), CI (4.1 +/- 1.2 L/min/m2), PAOP (15 +/- 4 mmHg), HR (98 +/- 16/min), and MAP (83 +/- 10 mmHg) were similar between groups and did not change during LD-DA therapy. Initial serum Cr in the RT group (1.6 +/- 0.4 mg/dL) was greater than that in controls (0.9 +/- 0.24 mg/dL), p < 0.05. Initial UO [0.26 +/- 0.10 mL/kg/h (RT) and 0.31 +/- 0.12 mL/kg/h (controls)] and initial UNa [8 +/- 62 meq/L (RT) and 54 +/- 28 meq/L (controls)] were not different. Urine output increased significantly compared with baseline in both groups [final UO 0.55 +/- 0.14 mL/kg/h (RT) and 0.96 +/- 0.41 mL/kg/h (controls)]. Final UNa [72 +/- 37 meq/L (RT) and 99 +/- 56 meq/L (controls)] were not different from each other or from baseline. CONCLUSIONS: LD-DA increases UO, but not UNa excretion, in RT patients with oliguria, comparably to controls. These data suggest that this effect is predominantly mediated by dopaminergic receptors, since the transplanted kidney is denervated and there were no significant associated changes in hemodynamic parameters during the study.

Acute acalculous cholecystitis: incidence, risk factors, diagnosis, and outcome.

The objective of this study was to review the incidence, risk factors, methods of diagnosis, and outcome of acute acalculous cholecystitis (AAC) and to identify the sensitivity and limitations of current radiographic modalities used to establish the diagnosis. Our study was a retrospective chart review in a tertiary-care university hospital. Over a 53-month period, 27 cases of AAC (17 males, 10 females; mean age 50 years; mean Acute Physiology and Chronic Health Evaluation II score, 17) were encountered. Of these, 14 (52%) occurred in critically ill patients and 17 (63%) in patients recovering from non-biliary tract operations. AAC occurred in 0.19 per cent of surgical intensive care unit admissions and accounted for 14 per cent (27 of 188) of all cases of acute cholecystitis. Presenting symptoms and laboratory values were nonspecific. Twenty patients had radiographic studies before surgery. Among the various radiological studies used for AAC, morphine cholescintigraphy had the highest sensitivity (9 of 10; 90%), followed by computed tomography (8 of 12; 67%) and ultrasonography (2 of 7; 29%). Ten of the 20 patients had more than one study done preoperatively. All 27 patients had an open cholecystectomy. AAC was associated with a high incidence of gangrene (17 of 27 cases; 63%), perforation (4 of 27; 15%), and abscess (1 of 27; 4%). The mortality rate was 41 per cent (11 of 27). We conclude that AAC is a rare, but potentially lethal, disease occurring in critically ill patients and those recovering from non-biliary tract operations. The clinical presentation is nonspecific, and significant delays in diagnosis result in a high incidence of gangrene, perforation, abscess, and death. To improve outcome, a high index of suspicion with early radiographic evaluation, often employing multiple studies, is necessary. An algorithm for the evaluation of patients for suspected AAC is proposed.

Surgical implications of obesity.

Obesity is perhaps the most significant public health problem facing the United States today. Obese patients are at increased risk for numerous medical problems, which can adversely affect surgical outcome. However, these risks have not uniformly translated into increased or prohibitive operative morbidity and mortality in this population. With appropriate perioperative precautions and monitoring, the incidence of serious cardiovascular and pulmonary complications can be minimized. Obese patients can be treated as safely and effectively as their normal weight counterparts under most circumstances and should not be denied surgical treatment for any disorder when surgery constitutes the most appropriate therapy. When indicated, surgical treatment should be considered for patients with clinically severe obesity, since currently it appears to offer the best long-term results for weight control and amelioration of comorbidity.

Preoperative intensive care unit admission and hemodynamic monitoring in patients scheduled for major elective noncardiac surgery: a retrospective review of 95 patients.

OBJECTIVE: To review experience with preoperative intensive care unit (ICU) admission and hemodynamic monitoring to determine which patients benefited and how. DESIGN: Retrospective review over 32-month period (1991 to 1994). SETTING: Surgical ICU of a university teaching hospital. PARTICIPANTS: Ninety-five patients admitted to the surgical ICU before a major elective noncardiac, nonthoracic surgical procedure. INTERVENTIONS: All patients underwent hemodynamic monitoring with a pulmonary artery catheter (PAC). Interventions were made at the discretion of the ICU attending and attending surgeon, based on a general algorithm. Patients were categorized based on history or hemodynamics. The historic classification was as follows: group I, patients with cardiac disease documented by history and cardiac imaging, n = 37; group II, patients with cardiac disease documented by history, but not cardiac imaging, n = 24; group III, patients without documented cardiac disease, but with other significant medical problems, n = 34. Hemodynamic classification considered patients to have subnormal parameters if the cardiac index was < 2.5 L/min/m2, the mixed venous oxygen saturation was < 65%, or the oxygen delivery index was < 350 mL/min/m2 (n = 45), and normal parameters if greater than these (n = 50). MAIN RESULTS: There were no differences in APACHE II scores. Group I patients had greater Goldman Cardiac Risk Indices than group III patients (7.4 +/- 4.8 v 5.0 +/- 3.0). Patients in group I had a significantly greater incidence of subnormal initial hemodynamic values (63%) than patients in group II (47%) or group III (32%). The incidence of postoperative cardiovascular complications among groups was not different. Fifty patients (52%) had normal hemodynamics initially; two (4%) developed postoperative cardiovascular complications compared with 10 patients (22%) of the 45 with subnormal initial hemodynamic values. Of these 45 patients, 24 (52%) had their hemodynamic parameters corrected preoperatively with crystalloids, packed red blood cells, inotropes, and/or afterload reduction. Two of these 24 patients (8%) experienced postoperative cardiovascular complications, compared with 8 of the remaining 21 patients who had no attempt to normalize their hemodynamic values preoperatively other than maintaining a normal pulmonary artery occlusion pressure. CONCLUSIONS: Patients who had normal initial preoperative hemodynamic parameters or abnormal initial parameters that were normalized preoperatively experienced significantly fewer perioperative cardiovascular complications than those with abnormal initial values that were not normalized preoperatively. These results suggest that there may be benefit to the practice of preoperative ICU admission, hemodynamic monitoring with a PAC, and "optimization" of cardiac function in selected patients undergoing major elective noncardiac surgery. Further studies are needed to better delineate the most appropriate patient populations and effective therapeutic protocol.

Changes in measured resting energy expenditure after Roux-en-Y gastric bypass for clinically severe obesity.

BACKGROUND: Roux-en-Y gastric bypass (RYGB) results in sustained weight loss and amelioration of comorbid conditions in patients with clinically severe obesity. The mechanism of weight loss after RYGB is not well defined. The objective of this study was to document the changes in measured resting energy expenditure (MREE) over time in patients with clinically severe obesity after RYGB. METHODS: We prospectively studied MREE in 70 patients (11 male, 59 female; body mass index [BMI], 40 to 80 kg/m2) treated by RYGB. MREE was measured by indirect calorimetry before operation and at 6 weeks and 3, 6, 12, 18, and 24 months after operation. Patients were stratified to hypometabolic ([HM] MREE less than 85% of Harris-Benedict [HB] predicted; n = 22) or normal metabolic rate ([NM] MREE +/- 15% HB predicted; n = 48) before operation; mean BMIs were HM, 53.4 +/- 11.0 kg/m2; NM, 51.4 +/- 9.8 kg/m2; p = not significant. MREE, weight loss, percent excess body weight loss (EWL), and energy intake were determined at each time point. RESULTS: Overall, MREE was significantly less than HB-predicted REE before operation (90 +/- 28%), but rose to become equal to the HB-predicted REE by 6 weeks (96 +/- 15%) and remained so. When stratified by initial metabolic rate, MREE increased significantly in the HM patients by 6 weeks, from 1329 +/- 604 kcal/day (55% of HB predicted) to 1882 +/- 398 kcal/day (88% of HB predicted) (p < 0.001), and MREE remained normal (2332 +/- 484 kcal/day to 2029 +/- 410 kcal/day) in the NM patients. Percent EWL was similar in both groups at each time. Energy intake was 2603 +/- 982 kcal/day before operation and fell to 815 +/- 196 kcal/day at 3 months, 969 +/- 241 kcal/day at 6 months, 1095 +/- 307 kcal/day at 12 months, 1259 +/- 466 kcal/day at 18 months, and 1373 +/- 620 kcal/day at 24 months, and was similar between the groups at each time point. Percent HB-predicted REE increased significantly after operation despite a significant decrease in energy intake. CONCLUSIONS: RYGB is associated with significant changes in MREE over time. In NM patients MREE fell over time consistent with weight loss but remained normal, whereas patients who were hypometabolic exhibited increases in MREE toward normal. These changes in MREE occurred despite reduced energy intake comparable to a very low calorie diet. This paradoxical effect on MREE may contribute to the enhanced weight loss associated with RYGB.

A prospective randomized trial of preoperative "optimization" of cardiac function in patients undergoing elective peripheral vascular surgery.

BACKGROUND: Previous investigations have suggested that preoperative invasive hemodynamic monitoring with "optimization" of cardiovascular function may favorably affect the outcome among patients undergoing peripheral vascular surgery. The purpose of this study was to evaluate the effect of preoperative optimization of hemodynamic parameters on outcome in patients undergoing aortic reconstruction (AR) or limb salvage procedures (LSP) in a randomized, prospective clinical trial. METHODS: All 72 patients who consented to participate in this study were admitted to the intensive care unit at least 12 hours before operation for placement of a pulmonary artery catheter (PAC). Patients who were randomized to the treatment group (n = 32) were "optimized" by adjusting their hemoglobin concentration, oxygen saturation (SaO2), cardiac output, or afterload until the mixed venous O2 saturation (SvO2) was at least 65%. The control group (n = 40) underwent placement of a PAC and had oxygen transport parameters measured without any attempt to optimize SvO2. RESULTS: There were no significant differences between the treatment and control groups with respect to age, gender, type of operation, initial Acute Physiology and Chronic Health Evaluation (APACHE) II score, SvO2, pulmonary artery occlusion pressure, or cardiac index. All treatment patients achieved an SvO2 of at least 65% before operation. Comparing the treatment and control groups, postoperative cardiovascular complications occurred in 25% versus 27%, intraoperative complications in 28% versus 20%, and death in 9% versus 5%, respectively. None of these differences was statistically significant as a whole or within the subgroups undergoing AR or LSP. CONCLUSIONS: These data suggest that preoperative optimization of cardiovascular function by using achievement of SvO2 above 65% as the end point does not result in any reduction of intraoperative or perioperative cardiac complications in patients undergoing PVS. Further studies with alternative assessments and manipulation of different cardiopulmonary parameters may yield additional information.

Hypoenergetic nutrition support in hospitalized obese patients: a simplified method for clinical application.

Nutrition support in obese hospitalized patients is controversial, with some practitioners advocating restricted energy or hypoenergetic feedings when patients are being actively treated for another disease. To eliminate the need for indirect calorimetry, this randomized, double-blind, prospective study was undertaken to determine whether obese hospitalized patients given a hypoenergetic parenteral regimen administered to provide 2 g protein x kg ideal body wt (IBW)(-1) x d(-1), could achieve nitrogen balance comparable with that of control subjects given isonitrogenous normoenergetic formula. Thirty obese hospitalized patients with an average body mass index (BMI; in kg/m2) of 35 were randomly assigned to the hypoenergetic [energy (kJ):nitrogen (g) = 314:1; energy (kcal):nitrogen (g) = 75:1; n = 16] or control [energy (kJ):nitrogen (g) = 628:1; energy (kcal):nitrogen (g) = 150:1; n = 14] formulas. The initial formula volume administered provided 2 g protein x kg IBW(-1) x d(-1). Nitrogen balance was determined on day 0 and weekly. The total daily energy intake [per kg actual body weight (ABW)] was 57 +/- 12 kJ (hypoenergetic) compared with 94 +/- 21 kJ (control), P < 0.001, and the nonprotein energy intake was 36 +/- 10 kJ (hypoenergetic) compared with 73 +/- 17 kJ (control), P < 0.001. Protein intake was the same per ABW, 2.0 +/- 0.2 and 2.0 +/- 0.1 g kg IBW(-1) x d(-1), NS, for the hypoenergetic and control formulas, respectively. Mean net nitrogen balance was not significantly different between the groups, even after patients were subgrouped by illness, nor was the percentage of patients achieving positive nitrogen balance. Duration of treatment averaged 10.5 +/- 2.6 d. Weight change did not differ significantly between groups. These data indicate that patients receiving hypoenergetic feedings providing 2 g protein x kg IBW(-1) x d(-1) achieved nitrogen balance comparable with patients given conventional total parenteral nutrition regimens, even when critically ill.

Erythromycin facilitates postpyloric placement of nasoduodenal feeding tubes in intensive care unit patients: randomized, double-blinded, placebo-controlled trial.

BACKGROUND: To determine whether administration of erythromycin (E) could facilitate passage of a nasoenteric feeding tube into the duodenum for postpyloric feedings, this randomized, double-blind, placebo-controlled trial was performed. METHODS: Fifty-seven patients were accrued from the surgical intensive care units (ICUs) of a tertiary-care university hospital. Patients enrolled were categorized as to the presence or absence of diabetes mellitus (DM). Those patients without DM were then subdivided into those with normal or depressed mental status. The three groups, normal (NMS), depressed mental status (DMS), or diabetes mellitus (DM), were then randomized independently to receive either E or placebo (P), followed by blind placement of a feeding tube. Tube placement was verified by an abdominal radiograph. RESULTS: Overall, the rate of postpyloric placement was 61% (19/31) in the E group, significantly better than 35% (9/26) in the P group (p < .05). In patients with NMS, the success rate with E was improved (64%, 9/14) compared with that with P (9%, 1/11) (p < .0005). In the DMS group, there was a 50% success rate (6/12) with E versus 63% (5/8) with P (not significant [NS]). In the DM group, 80% (4/5) of the patients had placement of the tube in the duodenum with E and 43% (3/7) with P (NS). CONCLUSIONS: These data suggest that, overall, E is effective in facilitating placement of a nasoenteric feeding tube into the duodenum in ICU patients. It is clearly beneficial in those patients with normal mental status and may be useful in patients with diabetes mellitus.

Nutrition support billing practices: results of a nationwide survey and responses from the Health Care Financing Administration.

In response to numerous changes in reimbursement for physician services, a survey was conducted of physician directors of nutrition support services to obtain information about current physician billing practices and reimbursement for nutrition support. Demographic data were obtained concerning the type of practice and institution, percent of time and income derived from nutrition support, and the source of individual billing practices. Responses to six clinical scenarios provided information about billing practices. The responses were collated, analyzed, and then compared with those of a senior official at the Health Care Financing Administration (HCFA). This report summarizes the results of the survey and the responses from HCFA. It is hoped that this information will be useful to nutrition support practitioners and administrators in understanding various aspects of billing for physician services for nutrition support.

Characterization of a murine model of acute lung injury (ALI): a prominent role for interleukin-1.

This report describes a model developed to study local and systemic events that occur as a result of acute lung injury (ALI). C57BL/6J mice were injected with a single intravenous dose (2, 4, and 6 micrograms) of 12-O-tetradecanoylphorbol-13-acetate (TPA). At 1, 2, 4, 12, 24, and 48 h, after injection, plasma was collected by sinus orbital puncture, bronchoalveolar lavage (BAL) was performed and cells and fluid were collected, lungs were perfused, and pulmonary tissue was isolated and processed for histological, immunochemical, and gene expression studies. The results indicate a dose-dependent increase in animal distress and a decrease in survival. TPA induced an early systemic response, reflected as an initial decrease in numbers of peripheral blood neutrophils at 1 h, followed at 2 h by a sustained increase. There was dose- and time-dependent increase in IL-1 beta mRNA synthesis, detected using RT-PCR, and in immunoreactive IL-1 alpha produced by both tissue-fixed pulmonary cells and cells within alveolar spaces. Infiltration of neutrophils into pulmonary tissue and increased protein content in BAL fluid was detected 2 h after injection of TPA. Disruptions in pulmonary architecture accompanied by the presence of highly vacuolated macrophages within the alveolar spaces and interstitial tissue were evident after IV injection of TPA. The study shows that injection of TPA induces reproducible dose- and time-dependent alterations in cell types, numbers, state of activation, and production of soluble mediators in the peripheral circulation within BAL and pulmonary tissue. Thus, this model offers a means to examine the cellular basis for the local and systemic alterations observed during ALI.

Increased incidence of nosocomial infections in obese surgical patients.

Obesity has long been considered a potential risk factor for poor outcome following surgical procedures. However, controversy exists regarding the clinical impact of this problem because of a paucity of data regarding the incidence and risk of nosocomial infections in obese surgical patients. This retrospective study was undertaken to compare the nosocomial infection rate in obese and normal weight surgical patients. All patients undergoing general, urologic, vascular, thoracic, or gynecologic surgical procedures between October 1 and December 31, 1991, were reviewed. Nosocomial infection data were obtained from the Department of Hospital Epidemiology. A total of 849 patients were evaluated, of which 536 (63%) were normal weight (BMI < 27 kg/m2), 175 (21%) were obese (BMI 27-31 kg/m2), and 138 (16%) were severely obese (BMI > 31 kg/m2). Age, mortality, and American Society of Anesthesia (ASA) risk scores did not differ among the three groups. There were significant increases in the number and percent of nosocomial infections in the obese populations, with rates of 0.05 per cent in normal weight, compared to 2.8 per cent and 4.0 per cent in obese and severely obese groups (P < 0.01). Infections consisted of seven wound infections, five C. difficile infections, one pneumonia, and three bacteremias. No differences in distribution between groups were evident. Mortality was similar among the groups. These data support the hypothesis that obesity is a significant risk factor for clinically relevant nosocomial infections in surgical patients.

Changes in patients' taste acuity after Roux-en-Y gastric bypass for clinically severe obesity.

OBJECTIVE: Patients who have undergone Roux-en-Y gastric bypass (RYGB) for clinically severe obesity often report an aversion to sweet foods and meat. This study was designed to determine whether changes in taste acuity occur after RYGB. DESIGN: This prospective, repeated measures trial evaluated acuity for sweet (sucrose) and bitter (urea) tastes, zinc status, and reported changes in taste perceptions in patients undergoing RYGB for weight reduction. SUBJECTS: Taste acuity and serum zinc level were measured in 14 subjects, 6 men and 8 women (mean preoperative body mass index [calculated as kg/m2] = 60.8 +/- 11.8 and mean age = 38.4 +/- 6 years), before surgery and 6 and 12 weeks after surgery. Inquiries regarding taste preferences were made at each postoperative visit with specific reference to sweets and meat. Serum zinc level was measured at the same visit. A noncontrolled comparison group of 4 subjects who were consuming a very-low-calorie diet also underwent taste acuity testing at similar intervals. MAIN OUTCOME MEASURES: The main outcome measures were recognition taste thresholds, serum zinc levels, and taste preference changes. STATISTICAL ANALYSIS: Analysis of variance with repeated measures over time, Pearson correlation coefficients, and post hoc analysis of variance were used to analyze data. RESULTS: Mean recognition thresholds for sucrose were 0.047 +/- 0.03 mol/L preoperatively and fell significantly to 0.024 +/- 0.01 and 0.019 +/- 0.01 mol/L at 6 and 12 weeks postoperatively, respectively. Overall, there were no significant differences in taste thresholds for urea over time; a significant difference was noted, however, in the pattern of change for urea between patients who reported an aversion to meats and those who did not. Zinc concentrations did not change during the study. APPLICATION/CONCLUSIONS: At 6 weeks postoperatively, all patients reported that foods tasted sweeter, and they modified food selection accordingly. Six patients reported an aversion to meats associated with increased nausea and vomiting. Acuity for sweet and bitter tastes may need to be considered when planning dietary modifications for patients undergoing RYGB.

Use of morphine cholescintigraphy in the diagnosis of acute cholecystitis in critically ill patients.

OBJECTIVE: To determine the efficacy of morphine enhanced radionuclide cholescintigraphy (MC) in the diagnosis of acute cholecystitis (AC) in critically ill patients. DESIGN: Retrospective chart review. SETTING: 2 university hospitals. PATIENTS AND METHODS: Records of all ICU patients who underwent MC as part of an evaluation for AC over an 8 year period were reviewed (n = 45). All patients initially had standard radionuclide cholescintigraphy (RC) performed which showed nonvisualization of the gallbladder (GB) and were then given morphine sulfate (0.05-0.1 mg/kg i.v.). RESULTS: The mean age was 54 years (range 18-84 years). Risk factors for AC included fasting in 41 patients (mean 12.4 days) and total parenteral nutrition in 32 patients. Signs of biliary sepsis included temperature > 100 degrees F in 38 patients, WBC > 10,000/ml3 in 40 patients, abdominal pain in 29 patients, and abnormal liver function tests in 42 patients. 23 patients had GB ultrasonography, with 7 showing stones. MC was positive (non-visualization) in 16 patients and negative (GB visualized) in 29, including 4 with gallstones. All patients in whom the GB was visualized did so within 1 h. There were 13 patients with positive MC who underwent operation; 12 had AC (9 acalculous, 3 calculous). Three patients were treated medically and recovered (false positive). All 29 patients with negative MC were true negatives. Overall, MC had an accuracy of 91%, sensitivity of 100%, specificity of 88%, positive predictive value of 75%, and negative predictive value of 100%. CONCLUSION: MC is a useful test in the evaluation of critically ill patients for suspected AC, particularly in patients with known risk factors or documented gallstones.

Morphine cholescintigraphy in the evaluation of hospitalized patients with suspected acute cholecystitis.

OBJECTIVE: The authors determined if the diagnosis of acute cholecystitis can be accurately made or reliably eliminated by the use of morphine-augmented radionuclide cholescintigraphy (morphine cholescintigraphy [MC]) in hospitalized patients in whom the diagnosis is in doubt. SUMMARY/BACKGROUND DATA: Diagnosis of acute cholecystitis, calculous or acalculous, may be difficult in patients hospitalized for abdominal pain or other illnesses. Clinical signs often are obscure, and routine imaging studies are nonspecific or associated with a high incidence of false-positive tests. The authors report the use of MC in the evaluation of 163 hospitalized patients for acute cholecystitis over an 8-year period. METHODS: All patients suspected to have acute cholecystitis initially had standard cholescintigraphy performed, which showed nonvisualization of the gallbladder, and then were given morphine sulfate (0.05-0.1 mg/kg, intravenously). Patients were divided into the following three groups: I--acute abdominal pain (N = 53); II--hospitalized for associated illness (N = 49); and III--critically ill (N = 61). RESULTS: Overall, MC confirmed the diagnosis of acute cholecystitis in 75 patients (46%), including 23 cases of acalculous cholecystitis. Visualization of the gallbladder occurred within 60 minutes of intravenous administration of morphine sulfate in all patients. Cystic duct obstruction and, presumably, the diagnosis of acute cholecystitis was excluded in 79 patients, including 38 who were critically ill. There were eight false-positive and one false-negative studies. Morphine cholescintigraphy had a sensitivity of 99%, a specificity of 91%, a positive predictive value of 0.9, a negative predictive value of 0.99, and an overall accuracy of 94%. CONCLUSIONS: In hospitalized patients with nonvisualization of the gallbladder after standard cholescintigraphy, MC is highly accurate, especially in predicting the absence of acute cholecystitis in patients with known risk factors.

Serum aldosterone concentrations and urine output in oliguric intensive care unit patients receiving low-dose dopamine.

OBJECTIVE: To determine whether the diuretic and natriuretic effects of low-dose dopamine (2.5 micrograms/kg/min) are associated with changes in serum aldosterone concentration. DESIGN: Prospective clinical study. SETTING: Surgical intensive care unit (SICU) of a university hospital. PARTICIPANTS: Oliguric (urine output < 0.5 mL/kg/h) SICU patients. All patients were resuscitated to pulmonary artery occlusion pressure > 10 mm Hg, mean arterial pressure > 65 mm Hg, and cardiac index > 2.5 L/min/m2. Patients with a serum creatinine concentration > 176.8 mumol/L (2.0 mg/dL), those who received diuretics within 12 hours prior to entry into the study, and renal transplant recipients were excluded. MAIN OUTCOME MEASURES: Hourly urine output (mean +/- SD) was recorded 2 hours before and for 6 hours after the initiation of low-dose dopamine. Urine sodium and serum aldosterone concentrations were obtained prior to and 6 hours after the start of low-dose dopamine. RESULTS: Fifteen patients were enrolled in the study. Urine output (mean +/- SD) increased from 0.31 +/- 0.11 mL/kg/h before to 0.80 +/- 0.34 mL/kg/h following low-dose dopamine (p < 0.01). Urine sodium concentrations increased from 46 +/- 32 mmol/L baseline to 72 +/- 53 mmol/L following low-dose dopamine (p < 0.05), and serum aldosterone concentrations decreased from 415.82 +/- 341.48 pmol/L prior to low-dose dopamine infusion to 256.04 +/- 204.17 pmol/L (p < 0.05). Cardiac output, pulmonary artery occlusion pressure, mean arterial pressure, and heart rate did not change. CONCLUSIONS: Low-dose dopamine significantly increases urine output and urine sodium excretion in oliguric, critically ill, surgical patients, and is associated with a decrease in serum aldosterone concentration. The diuretic and natriuretic effects of low-dose dopamine may be, in part, related to a dopamine-mediated inhibition of aldosterone secretion.