Daniel T. Dempsey

Energy expenditure in malnourished gastrointestinal cancer patients.

Cancer cachexia, a common finding in patients with gastrointestinal (GI) malignancy, is frequently attributed to tumor‐induced aberrations in host energy expenditure. To characterize the frequency and severity of aberrations in energy expenditure in GI cancer patients, and to identify the potential influence of tumor characteristics in this group, the authors measured resting energy expenditure (REE) by indirect calorimetry in 173 patients and compared REE to predicted energy expenditure (PEE) from the Harris‐Benedict formulae based on current body weight. Fifty‐eight percent of patients had abnormal REE (normal REE = ±10% PEE); 36% (62 of 173) were hypometabolic (REE <90% PEE), and 22% (39 of 173) were hypermetabolic (REE >110% PEE). Host and tumor factors were compared between metabolic groups to identify potential determinants of abnormal energy expenditure. Differences between groups cannot be explained by differences in patient age, sex, body size, nutritional status, tumor burden, or duration of disease. Resting energy expenditure does not correlate with percent of weight loss, serum albumin, or duration of disease. Analysis by tumor site reveals patients with pancreatic or hepatobiliary tumors to be predominantly hypometabolic; gastric cancer patients tend to be hypermetabolic, whereas patients with colorectal or esophageal neoplasms are more evenly distributed across metabolic groups, the largest portion being normometabolic (X2 = 20.7, P <0.02). The majority of GI cancer patients have abnormal REE which is unpredictable and not uniformly hypermetabolic. The determinants of these abnormalities do not appear to be age, sex, body size, nutritional status or tumor burden. Primary tumor site is a major determinant of energy expenditure in GI cancer patients. Cancer 53:1265‐1273, 1984.

Trends and Outcomes of Hospitalizations for Peptic Ulcer Disease in the United States, 1993 to 2006

Objectives:Despite progress in diagnosis and treatment, peptic ulcer disease (PUD) remains a common reason for hospitalization and operation. The purpose of this study was to quantify the time trends of hospitalizations and operations for PUD in the United States (US) since 1993. Data and Methods:The Healthcare Cost and Utilization Project Nationwide Inpatient Sample is a 20% stratified sample of all hospitalizations in the United States. It was used to study hospitalizations with PUD as the principal diagnosis during 1993 to 2006, including details on ulcer site, complications, procedures, and mortality. Statistical methods included the χ2 test and multivariate logistic regression. Results:The national estimate of hospitalizations for PUD decreased significantly from 222,601 in 1993 to 156,108 in 2006 (−29.9%), with a larger reduction in duodenal ulcers (95,552 in 1993 vs. 60,029 in 2006, −37.2%) than gastric ulcers (106,987 in 1993 vs. 86,064 in 2006, −19.6%). The inpatient mortality rate of PUD decreased from 3.8% to 2.7% during 1993 to 2006 (P < 0.001). Hemorrhage remained the most common complication (71.6% in 1993; 73.3% in 2006) but perforation had the highest mortality (15.1% in 1993; 10.6% in 2006). In comparison to 1993, patients hospitalized for PUD in 2006 more frequently had endoscopic treatment to control bleeding (12.9% vs. 22.2%, P < 0.001), similar use of surgical oversewing of ulcer (7.6% vs. 7.4%), less use of gastrectomy (4.4% vs. 2.1%, P < 0.001), and less use of vagotomy (5.7% vs. 1.7%, P < 0.001). In multivariate logistic regressions, the determinants of mortality were similar in 1993 and 2006. Conclusions:Hospitalizations for PUD decreased in the United States from 1993 to 2006, suggesting a decrease in the prevalence and/or severity of ulcer complications over this recent time period. Despite increased patient age and comorbidities, there has been a significant decrease in PUD mortality, a significant increase in the use of therapeutic endoscopy for bleeding ulcer, and a significant decrease in the use of definitive surgery (vagotomy or resection) for ulcer complications.

Sphincterlike Thoracoabdominal High Pressure Zone After Esophagogastrectomy

BACKGROUND The contribution of the crural diaphragm to the gastroesophageal high pressure zone (HPZ) may be important in prevention of gastroesophageal reflux. The purpose of this study was to investigate the manometric characteristics of the thoracoabdominal junction in patients after surgical removal of the lower esophageal sphincter. METHODS Ten patients with prior esophagogastrectomy were studied manometrically. RESULTS Esophageal manometry showed a HPZ and pressure inversion point distal to the anastomosis in 9 of 10 patients. Midrespiratory and end expiratory pressures were 14 +/- 7 and 6 +/- 4 mm Hg above intra-abdominal pressure, respectively. Breath holding caused inhibition of the phasic pressure component. This HPZ relaxed partially in response to deglutition (60% +/- 22%) and contracted in response to increased intra-abdominal pressure induced by either leg lifts or abdominal compression (delta HPZ/delta intra-abdominal pressure = 1.87 +/- 0.64 and 1.96 +/- 0.40, respectively). CONCLUSIONS This study shows an HPZ at the thoracoabdominal junction after surgical removal of the lower esophageal sphincter. We suggest that this sphincterlike HPZ is due to the crural diaphragm.

Acute experimental colitis decreases colonic circular smooth muscle contractility in rats

Distal colitis decreases the contractility of the underlying circular smooth muscle. We examined how time after injury and lesion severity contribute to the decreased contractility and how colitis alters the calcium-handling properties of the affected muscle. Distal colitis was induced in rats by intrarectal administration of 4% acetic acid. Contractile responses to acetylcholine, increased extracellular potassium, and the G protein activator NaF were determined for circular muscle strips from sham control and colitic rats at days 1, 2, 3, 7, and 14 postenemas. Acetylcholine stimulation of tissues from day 3colitic rats was performed in a zero calcium buffer, in the presence of nifedipine, and after depletion of intracellular stores of calcium. The colitis was graded macroscopically as mild, moderate, or severe. Regardless of agonist, maximal decrease in force developed 2 to 3 days posttreatment, followed by a gradual return to control by day 14. The inhibitory effect of colitis on contractility increased with increasing severity of inflammation. Limiting extracellular calcium influx had a greater inhibitory effect on tissues from colitic rats; intracellular calcium depletion had a greater inhibitory effect on tissues from control animals. The data suggest that both lesion severity and time after injury affect the contractile response of circular smooth muscle from the inflamed distal colon. Impaired utilization of intracellular calcium may contribute to the decreased contractility.Distal colitis decreases the contractility of the underlying circular smooth muscle. We examined how time after injury and lesion severity contribute to the decreased contractility and how colitis alters the calcium-handling properties of the affected muscle. Distal colitis was induced in rats by intrarectal administration of 4% acetic acid. Contractile responses to acetylcholine, increased extracellular potassium, and the G protein activator NaF were determined for circular muscle strips from sham control and colitic rats at days 1, 2, 3, 7, and 14 postenemas. Acetylcholine stimulation of tissues from day 3 colitic rats was performed in a zero calcium buffer, in the presence of nifedipine, and after depletion of intracellular stores of calcium. The colitis was graded macroscopically as mild, moderate, or severe. Regardless of agonist, maximal decrease in force developed 2 to 3 days posttreatment, followed by a gradual return to control by day 14. The inhibitory effect of colitis on contractility increased with increasing severity of inflammation. Limiting extracellular calcium influx had a greater inhibitory effect on tissues from colitic rats; intracellular calcium depletion had a greater inhibitory effect on tissues from control animals. The data suggest that both lesion severity and time after injury affect the contractile response of circular smooth muscle from the inflamed distal colon. Impaired utilization of intracellular calcium may contribute to the decreased contractility.

Caloric requirements in total parenteral nutrition.

Resting energy expenditure (REE) was measured in 100 consecutive total parenteral nutrition (TPN) patients. Only forty-eight percent of the measured REEs were within 90-110% of the predicted Harris-Benedict values. A literature review revealed 191 published guidelines for non-protein caloric requirements of hospitalized TPN patients. These guidelines were appropriately matched and applied to the 100 individual TPN patients. The relationship between the recommended caloric supply and measured caloric expenditure was minimal. The recommendations exceeded measured REE by an average of 1076 +/- 660 kcal/day. These published guidelines were substantially above and below caloric requirements based on measured REE for both fat maintained (130% REE) and fat depleted (150% REE) patients. Following published guidelines rather than standards based on measured REE results in the administration of 6947 excess liters of TPN per year. Improvement in the precision of TPN caloric prescription can be accomplished by using measured REE as a reference base. When published guidelines were compared to prescriptions based on measured REE it was found that published guidelines were inaccurate both overall and individually and a substantial cost savings justifies actual measurement of energy needs.

The effects of intraoperative hypothermia on surgical site infection: An analysis of 524 trauma laparotomies

Objectives:Our primary study objective was to determine whether intraoperative hypothermia predisposes patients to postoperative surgical site infections (SSI) after trauma laparotomy. Background:Although intraoperative normothermia is an important quality performance measure for patients undergoing colorectal surgery, the effects of intraoperative hypothermia on SSI remain unstudied in trauma. Methods:A review of all patients (July 2003–June 2008) who survived 4 days or more after urgent trauma laparotomy at a level I trauma center revealed 524 patients. Patient characteristics, along with preoperative and intraoperative care focusing on SSI risk factors, including the depth and duration of intraoperative hypothermia, were evaluated. The primary outcome measure was the diagnosis of SSI within 30 days of surgery. Cut-point analysis of the entire range of lowest intraoperative temperature measurements established the temperature nadir that best predicted SSI development. Single and multiple variable logistic regression determined SSI predictors. Results:The mean intraoperative temperature nadir of the study population (n = 524) was 35.2°C ± 1.1°C and 30.5% had at least 1 temperature measurement less than 35°C. Patients who developed SSI (36.1%) had a lower mean intraoperative temperature nadir (P = 0.009) and had a greater number of intraoperative temperature measurements <35°C (P < 0.001) than those who did not. Cut-point analysis revealed an intraoperative temperature of 35°C as the nadir temperature most predictive of SSI development. Multivariate analysis determined that a single intraoperative temperature measurement less than 35°C independently increased the site infection risk 221% per degree below 35°C (OR: 2.21; 95% CI: 1.24–3.92, P = 0.007). Conclusions:Just as intraoperative hypothermia is an SSI risk factor in patients undergoing elective colorectal procedures, intraoperative hypothermia less than 35°C adversely affects SSI rates after trauma laparotomy. Our results suggest that intraoperative normothermia should be strictly maintained in patients undergoing operative trauma procedures.

Trends and perioperative outcomes of inpatient antireflux surgery in the United States, 1993-2006.

Antireflux surgery is an effective treatment for gastroesophageal reflux disease, but postoperation complications and durability may be problematic. The objective of the study was to determine whether inpatient antireflux surgery continued to decline in the United States due to concerns about its long-term effectiveness and the popularity of gastric bypass surgery and to assess recent changes in its perioperative outcomes. Using the Nationwide Inpatient Sample, we identified adult patients undergoing inpatient antireflux surgery during 1993-2006 and compared the trends of inpatient antireflux surgery with inpatient gastric bypass surgery. Perioperative complications included laceration, splenectomy, transfusion, esophageal dilation, total parenteral nutrition, and infection. Inpatient antireflux surgery increased from 9173 in 1993 to 32 980 in 2000 (+260%) but then decreased to 19 668 in 2006 (-40%). Compared with 2000, patients undergoing inpatient antireflux surgery in 2006 were older (49.9 ± 32.4 vs. 54.6 ± 33.6 years) and had a longer length of stay (3.1 ± 10.0 vs. 3.7 ± 13.4 days), more complications (4.7% vs. 6.1%), and higher mortality (0.26% vs. 0.54%) (all P < 0.05). Compared with inpatient gastric bypass surgery, length of stay was longer and mortality was higher for inpatient antireflux surgery in 2006, but neither was significant controlling for age. In 2006, perioperative outcomes of inpatient antireflux surgery were better in high-volume hospitals (all P < 0.01). Inpatient antireflux surgery continued to decline in the United States from 2000 to 2006, concomitant with a dramatic increase in inpatient gastric bypass surgery. Older patient age and worsening perioperative outcomes for inpatient antireflux surgery suggest increased medical complexity and possibly a larger share of reoperations over time. Designating centers of excellence for antireflux surgery based on local expertise may improve outcomes.

Comparison of outcomes following open and laparoscopic esophagomyotomy for achalasia.

AbstractBackground: Minimally invasive esophagomyotomy is replacing open surgery for achalasia, but data comparing these procedures performed by the same surgical team are sparse. The purpose of this study was to compare the morbidity and clinical outcome following laparoscopic and open esophagomyotomy. Methods: Twelve consecutive patients referred for elective surgery between August 1995 and August 1997 underwent laparoscopic myotomy and partial fundoplication. They were compared to a group of 10 patients chosen from a larger pool of 20 patients who had open surgery during the same period performed by our own group. The mean length of follow-up in the laparoscopic group was 16 months; in the open group, it was 60 months. Both groups had similar demographics and clinical features. Each patient had at least one previous pneumatic dilatation. Inpatient records were reviewed. Patients were interviewed using a symptom assessment and patient satisfaction questionnaire. Results: As compared to the open operation, laparoscopic esophagomyotomy with partial fundoplication resulted in significantly (p < 0.05) less blood loss (50 ± 26 cc versus 220 ± 127 cc), parenteral narcotic use (2.1 ± 1.0 days versus 5.3 ± 1.4 days), time in hospital (2.7 ± 1.0 days versus 8.8 ± 2.6 days), and time off work (19 ± 16 days versus 85 ± 60 days). There were similar results for the laparoscopic and open groups in the improvement in dysphagia (92% versus 90%) and patient satisfaction with surgery (84% versus 80%). Conclusions: Laparoscopic esophagomyotomy for achalasia results in symptomatic improvement and high patient satisfaction comparable to the open procedure but with significantly less morbidity.

Trends of Heller Myotomy Hospitalizations for Achalasia in the United States, 1993–2005: Effect of Surgery Volume on Perioperative Outcomes

OBJECTIVES:Achalasia is a rare chronic disorder of esophageal motor function. Single-center reports suggest that there has been greater use of laparoscopic Heller myotomy for achalasia in the United States since its introduction in 1992. We aimed to study the trends of Heller myotomy and the relationship between surgery volume and perioperative outcomes.DATA AND METHODS: The Healthcare Cost and Utilization Project Nationwide Inpatient Sample (NIS) is a 20% stratified sample of all hospitalizations in the United States. It was used to study the macro-trends of Heller myotomy hospitalizations during 1993–2005. We also used the NIS 2003–2005 micro-data to study the perioperative outcomes of Heller myotomy hospitalizations, using other achalasia and laparoscopic cholecystectomy hospitalizations as control groups. The generalized linear model with repeated observations from the same unit was used to adjust for multiple hospitalizations from the same hospital.RESULTS:The national estimate of Heller myotomy hospitalizations increased from 728 to 2,255 during 1993–2005, while its mean length of stay decreased from 9.9 to 4.3 days. Of the 1,117 Heller myotomy hospitalizations in the NIS 2003–2005, 10 (0.9%) had the diagnosis of esophageal perforation at discharge. Length of stay was negatively correlated with a hospitals number of Heller myotomy per year (correlation coefficient −0.171, P < 0.001). In multivariate log-linear regressions with a control group, a hospitals number of Heller myotomy per year was negatively associated with length of stay (coefficient −0.215 to −0.119, both P < 0.001) and total charges (coefficient −0.252 to −0.073, both P < 0.10). These findings were robust in alternative statistical models, specifications, and subgroup analyses.CONCLUSIONS:On a national level, the introduction of laparoscopic Heller myotomy for achalasia was associated with greater use of surgery and shorter length of stay. A larger volume of Heller myotomy in a hospital was associated with better perioperative outcomes in terms of shorter length of stay and lower total charges.

Increased contribution of protein oxidation to energy expenditure in head-injured patients.

Six patients with acute head injury (initial GCS 4.8 +/- 1.7) were studied to determine the contribution of protein oxidation to resting energy expenditure (REE). Patients were studied on the second or third day post-injury and prior to implementation of nutritional support. Variables measured included REE by indirect calorimetry (normalized to percent predicted energy expenditure calculated from the Harris-Benedict equation). 24-hr urinary nitrogen excretion, calorie, and nitrogen intake. All patients received dexamethasone (39 +/- 2 mg/day) and three received pentobarbital. Mean REE was widely variable, ranging from 43 to 128% of predicted (mean, 90 +/- 31%). Mean 24-hr urinary nitrogen excretion was 16.5 +/- 5.8 g. The contribution of protein oxidation to REE was 30 +/- 4%. The contribution of protein oxidation to REE did not parallel REE (r = -0.237, p = NS) or REE expressed as percent predicted (r = -0.258, p = NS). The contribution of protein oxidation to energy expenditure is greater in acute heat trauma than previously described soft tissue injury and sepsis. The observed excessive nitrogen catabolism and increased contribution of protein oxidation to resting energy expenditure suggest accentuated protein requirements in respect to energy needs in head-injured patients.