The role of the community teaching hospital in surgical undergraduate education.

BACKGROUND: Significant changes in surgical practice have resulted in a reexamination of surgical undergraduate education. The increasing emphasis toward ambulatory procedures positions the community hospital as an excellent alternative site for surgical education. This study compares the quality of one medical school's surgical education at a principal teaching hospital to that of affiliated teaching hospitals. METHODS: Surgical undergraduate education offered through four programs was evaluated for 1993 to 1997. Students' performance was objectively rated by the National Board Examination in surgery, an oral examination, and a clinical appraisal. A subjective appraisal was determined via students' clerkship evaluation. RESULTS: There was a significant difference (P <0.01) in National Board Examination scores and clerkship evaluations that favored some affiliated teaching hospitals over the principal teaching hospital. CONCLUSION: The quality of surgical undergraduate education, documented by objective testing and subjective perception, indicated that the education obtained at the affiliated hospitals was at least equivalent to the principal teaching hospital.

Venous gas embolism during endoscopy.

Venous gas embolism is a rare but serious complication of laparoscopic and endoscopic procedures. We describe the case of a 33-year-old woman with a strictured hepaticojejunostomy anastomosis who was treated with transabdominal endoscopic balloon dilation. During the procedure, she suffered a venous gas embolus with immediate cardiovascular collapse. After treatment with pressors, electrical cardioversion, and multiple aspirations of the right ventricle, the patient recovered fully. We reviewed all reported cases of venous gas embolism during endoscopy over the past 30 years and identified multiple risk factors. We suggest precautions to minimize future complications in patients at increased risk.

Ketorolac versus meperidine for pain relief after orthopaedic surgery.

In this double-blind, randomized, multicenter study, 244 patients with at least moderate pain after major orthopaedic surgery received intramuscular Ketorolac (60 mg followed by 30 mg) or intramuscular meperidine (100 mg or placebo) every 2 to 6 hours as needed for as many as 5 days. Analgesic response was evaluated for 6 hours after initial study drug administration and thereafter each night at bedtime. Both active treatment groups had similar 3-hour summed pain intensity difference and 3-hour total pain relief scores after the first dose that were superior to placebo. The 6-hour summed pain intensity difference and total pain relief scores were significantly higher with Ketorolac than with meperidine or placebo. The mean daily categorical pain intensity scores were comparable with Ketorolac and meperidine, and both were significantly superior to placebo. Patient ratings of overall medication efficacy were significantly better with Ketorolac than with meperidine. In both patient and observer evaluations, Ketorolac was significantly better tolerated than meperidine, and the number of patients reporting adverse events was lower with Ketorolac than with meperidine. Following major orthopaedic surgery, Ketorolac provided effective analgesia that was superior to placebo and at least comparable with meperidine. Ketorolac was better tolerated than meperidine.

Conversion of failed or complicated vertical banded gastroplasty to gastric bypass in morbid obesity.

BACKGROUND: Previous studies have documented a significantly better we weight loss for gastric bypass (GBP) than for vertical banded gastroplasty (VGB). Additional problems associated with VBG include intractable vomiting or gastroesophageal (GE) reflux, intragastric migration of the polypropylene band, staple line disruption, or inadequate weight loss due to excessive ingestion of high-calorie liquid or soft carbohydrates. PATIENTS AND METHODS: Fifty-eight morbidly obese patients underwent conversion from VBG to GBP for either weight-loss failure (15) or complications of VBG (43), including 2 who where referred with anastomotic leaks and peritonitis, 3 with band erosion, 15 with staple line disruption, and 23 with stomal stenosis, of whom 6 had severe GE reflux, with a Barrett's esophagus in 1. RESULTS: Percentage of excess weight loss in the 53 patients followed up for at least 1 year after conversion increased from 36% +/- 24% to 67% +/- 18%, and in the 15 "sweets eaters" from 20% +/- 19% to 70% +/- 19% (both P <0.001), was equal to weight loss after primary GBP, and was reasonably constant over 8 years in those patients who could be contacted for follow-up, although average follow-up after 5 years was only 45% All patients had resolution of GE reflux symptoms immediately after surgery and for at least 1 year or at last contact. Complications of conversion included 2 anastomotic leaks with major wound infections (1 in a referred patient requiring emergency subtotal gastrectomy following a VBG leak), 3 staple line disruptions (2 subclinical), 3 small-bowel obstructions, and 20 marginal ulcers or stomal stenoses (all responded to endoscopic balloon dilation or acid reduction therapy). Hemoglobin, calcium, and vitamin B12 levels remained within normal levels with prophylactic supplementation in patients who returned for follow-up evaluation. CONCLUSIONS: These data support the efficacy of conversion to GBP in morbidly obese patients with a failed or complicated VBG.

Greater risk of incisional hernia with morbidly obese than steroid-dependent patients and low recurrence with prefascial polypropylene mesh.

BACKGROUND: Incisional hernia is a serious complication of abdominal surgery. We compared incisional hernia frequency following gastric bypass (GBP) for morbid obesity versus total abdominal colectomy and ileal pouch-anal anastomosis (IPAA) for ulcerative colitis. A prefascial polypropylene mesh repair was also evaluated. PATIENTS AND METHODS: All patients had midline incisions, xiphoid to umbilicus in GBP patients and midepigastrium to pubis in IPAA patients. Fascia were closed with running No. 2 polyglycolic acid suture. Ninety-eight patients underwent prefascial polypropylene mesh repair; 80 were GBP patients, 46 had 1 previous repair, and 17 had 2 to 9 previous repairs (6 with properitoneal mesh). RESULTS: Incisional hernia occurred in 20% (198/968) of GBP patients (19% without versus 41% with a previous hernia, P < 0.001) versus 4% (7/171) of the IPAA patients (P < 0.001), of whom 102 (60%) were taking prednisone (32 +/- 2 mg/d) and 5 were quite obese (body mass index > or = 30 kg/m2). Additional risk factors for hernia in GBP patients included wound infection, diabetes, sleep apnea, and obesity hypoventilation. For the 98 patients who underwent prefascial polypropylene mesh repair, the mean follow-up was 20 +/- 2 months (range 6 to 104), and complications occurred in 35% of patients, including minor wound infection (12%), major wound infection (5%), seroma (5%), hematoma (3%), chronic pain (6%), and recurrent hernia (4%). CONCLUSIONS: Severe obesity is a greater risk factor for incisional hernia and hernia recurrence than chronic steroid use in nonobese colitis patients. A prefascial polypropylene mesh repair minimizes recurrence.

A second large controlled clinical study of E5, a monoclonal antibody to endotoxin: results of a prospective, multicenter, randomized, controlled trial. The E5 Sepsis Study Group.

OBJECTIVE: To evaluate the safety and efficacy of E5, a murine, monoclonal antibody directed against endotoxin, in the treatment of patients with Gram-negative sepsis. DESIGN: A multicenter, randomized, double-blind, placebo-controlled trial. SETTING: Fifty-three hospitals across the United States, including university medical centers, Veterans Affairs Medical Centers, and community hospitals. PATIENTS: 847 patients were randomized into this study. Enrolled patients met criteria for three conditions: a) known or suspected Gram-negative infection; b) clinical evidence of sepsis; and c) signs of end-organ dysfunction. Patients with refractory shock were excluded from the study. INTERVENTIONS: Two doses of E5 (2 mg/kg/day by intravenous infusion 24 hrs apart), or placebo that was identical in appearance were administered. In addition, all patients received standard supportive therapy and broad-spectrum antibiotics. MEASUREMENTS AND MAIN RESULTS: The primary end point was mortality over 30 days. Secondary outcome measures included the resolution and prevention of organ failure in the same two populations. Additionally, the safety of E5 was evaluated. There was no significant improvement in survival over 30 days among patients with Gram-negative sepsis who received E5 compared with those patients who received placebo (n = 530; p = .21). In addition, E5 did not improve survival for patients with Gram-negative sepsis and organ failure (n = 139; p = .3). However, a significantly greater percentage of patients with Gram-negative sepsis experienced resolution of major organ failure if they received E5, compared with those patients who received placebo (n = 139; 48% E5 vs. 25% placebo; p = .005). This result extended to all patients who entered the study with one or more major organ failures, regardless of the etiology of the infection (n = 225; 41% E5 vs. 27% placebo; p = .024). E5 also provided protection against the development of some organ failures, but significant prevention was only observed for adult respiratory distress syndrome (p = .007) and central nervous system dysfunction (p = .050). Hypersensitivity reactions attributable to E5 occurred in 2.6% of patients. An asymptomatic antibody response occurred in 44% of the E5-treated patients and in 12% of the patients who received placebo. CONCLUSIONS: In this study, E5 did not reduce mortality in nonshock patients with Gram-negative sepsis whether or not those patients also had organ failure. However, E5 did result in greater resolution of organ failure in patients with Gram-negative sepsis. This benefit extended to those patients with suspected Gram-negative etiology. This finding is important because patients with suspected Gram-negative sepsis and organ failure can be identified without waiting for culture results. In addition, E5 resulted in the prevention of adult respiratory distress syndrome and central nervous system organ failure. However, more studies are needed to determine if this result can be extended to organ failure in general. E5 is safe as a treatment for patients with Gram-negative sepsis.

Assessment of 24-hour gastric pH measurements in trauma patients receiving intravenous famotidine by intermittent bolus versus continuous infusion administration.

OBJECTIVE: To compare the effects of intermittent bolus versus continuous infusion intravenous famotidine on gastric pH in critically ill trauma patients. DESIGN: Twenty patients were randomized to receive famotidine by intermittent bolus or continuous infusion for 24 hours. Patients fasted during the study period. Hourly gastric pH measurements were made using an indwelling sensor/sump tube. SETTING: The study was conducted in a university teaching hospital. PARTICIPANTS: Adult patients admitted to the neurosurgical or surgical/trauma intensive care unit within 72 hours of traumatic injury were enrolled in the study if they had two consecutive hourly gastric pH readings of < 4 without receiving antacids, sucralfate, or histamine2-antagonists. MAIN OUTCOME MEASURES: Groups were compared with regard to (1) total dose of famotidine received/24 hours, and (2) number of dosage changes required to maintain a gastric pH value of > or = 4. RESULTS: The median dose of famotidine required to maintain a gastric pH > or = 4 was 50 mg/24 h (25th-75th percentiles = 40-55 mg) in the intermittent bolus group compared with 42 mg/24 h (25th-75th percentiles = 42-52 mg) in the continuous infusion group (p = 0.9577). A dosage increase was required by 5 of 8 patients (62 percent) receiving intermittent bolus therapy, whereas only 2 of 8 patients (25 percent) in the continuous infusion group required a dosage adjustment (p = 0.315, power = 0.318). CONCLUSIONS: Intravenous famotidine (40-50 mg/d) effectively controlled gastric pH in critically ill trauma patients. Patients treated with intermittent bolus therapy required slightly more drug and more frequent dosage adjustments to achieve a gastric pH > or = 4. These differences did not reach statistical significance.

Derangements in peripheral glucose and oxygen utilization induced by catabolic hormones.

OBJECTIVE: To assess if the derangements in peripheral glucose, lactate, and oxygen utilization that are observed in severely injured patients are due to the hormonal response to injury or are related to the extent of the wound. DESIGN: Comparison study. INTERVENTIONS: The catabolic hormones epinephrine, cortisol, and glucagon were infused simultaneously into the femoral artery of six healthy volunteers, thus simulating the hormonal milieu associated with severe trauma in an uninjured leg. SETTING: Clinical research center at a university-affiliated hospital. PATIENTS: Young, adult males deemed healthy by screening medical history, physical examination, and blood chemistries. MEASUREMENTS AND MAIN RESULTS: Substrate net balance and indirect calorimetry measurements were performed before and then at the completion of 2 hrs of catabolic hormone infusion. Catabolic hormones elicited significant increases in leg glucose uptake and oxidation, and an increased net efflux from the leg of lactate and alanine. While leg oxygen delivery also increased, catabolic hormones failed to alter peripheral oxygen consumption. CONCLUSIONS: Catabolic hormones can elicit a similar peripheral metabolic response in an uninjured leg as that reported previously by Wilmore et al. in severely burned extremities. This finding suggests that the hormonal milieu associated with severe injury is influential in regulating peripheral glucose and oxygen utilization and that wound inflammation is not an essential component of this response.

Interleukin-1 receptor antagonist improves survival and preserves organ adenosine-5'-triphosphate after hemorrhagic shock.

BACKGROUND: This study was designed to determine the role of interleukin-1 (IL-1) in hemorrhagic shock death. METHODS: Pentobarbital anesthetized C3H/HeN mice (n = 59) were prepared with a femoral arterial catheter and were randomized to treatment with an IL-1 receptor antagonist (IL-1ra, 10 mg/kg, n = 29) or an equal volume of phosphate-buffered saline solution (vehicle, n = 30) by subcutaneous bolus injection at 15 minutes before hemorrhage and again at 120 minutes. Continuous posthemorrhage delivery of IL-1ra or vehicle was performed in each group (1.5 mg IL-1ra in 30 microliters/day) through a subcutaneous osmotic pump. Rapid hemorrhage of 4 ml/100 gm weight was followed by normal saline resuscitation of 12 ml/100 gm 60 minutes later. RESULTS: Survival analysis by Wilcoxon rank sum analysis revealed a significantly improved 5-day survival in IL-1ra-treated mice (n = 15, 20%) as compared with vehicle-treated mice (n = 14, 6%, p < 0.001). To determine a possible mechanism of this survival advantage, the remaining mice in each treatment group were killed at 30 minutes to obtain blood and tissue samples from the heart, liver, and kidney for measurement of adenosine-5'-triphosphate (ATP). No difference in hematocrit, circulating neutrophils, or levels of glucose, lactate, or tumor necrosis factor was identified between groups to explain the improved outcome. IL-1ra prevented hemorrhage-induced ATP depletion observed in vital organs of vehicle-treated mice. CONCLUSIONS: The data implicate IL-1 in shock-induced ATP depletion and suggest IL-1ra may improve hemorrhagic shock survival by preventing ATP depletion in vital organs.

Prostaglandins, thromboxanes, leukotrienes, and cytochrome P-450 metabolites of arachidonic acid.

Arachidonic acid is metabolized via three major enzymatic pathways: cyclooxygenase, lipoxygenase, and cytochrome P-450. The cyclooxygenase pathway gives rise to the prostaglandins and thromboxane A2. The lipoxygenase pathway produces the leukotrienes and 5-, 12-, and 15-hydroxyeicosatetraenoic acids. The cytochrome P-450 pathway metabolites are oxygenated metabolites of arachidonic acid. Synthesis of several of the cyclooxygenase and lipoxygenase metabolites are increased in circulatory shock. A potential role for several of these compounds in the pathophysiologic sequelae of endotoxic and septic shock has been implied from a combination of animal and human studies. There are no studies that have explored a potential role for cytochrome P-450 metabolites in the pathogenesis of circulatory shock.

Stress ulcers and organ failure in intubated patients in surgical intensive care units.

This study compared prophylactic administration of either intragastric misoprostol (200 micrograms four times a day), a prostaglandin E1 analog, or bolus intravenous cimetidine (300 mg every 6 hours) in preventing stress lesions and stress bleeding in 127 adult postoperative patients who required mechanical ventilation and also had developed hypotension or sepsis. Both drug treatments were equally effective in preventing the development of diffuse gastritis (greater than 10 gastric hemorrhagic lesions) and in preventing upper gastrointestinal hemorrhage (UGIH). The combined data from both groups showed that for the 44 (35%) patients who died, death was significantly associated with the presence at study entry of renal failure (64% of 25 patients with renal failure died), hepatic failure (57% of 23 patients) or coagulopathy (62% of 29 patients) (p less than 0.02 for each), and with the number of organ system failures at study entry (48% of 69 patients with multiple organ system failures died, p less than 0.001). Death was also significantly associated with the presence of adult respiratory distress syndrome (ARDS) at study entry or the development of ARDS (63% of 24 patients with ARDS died, p less than 0.001), and the development of UGIH (5% of 93 patients with known bleeding outcome died, p less than 0.05). The number of stress lesions that developed was significantly associated with subsequent UGIH (p less than 0.001). Additional organ system failure developed during the study in 31% of the 127 patients, as did diffuse gastritis in 20% of 111 patients who had a follow-up endoscopy. These results demonstrate that postoperative patients who require mechanical ventilation and have hypotension or sepsis are at significant risk for the development of stress gastric lesions and multiple organ system failure even when prophylaxis for stress ulcers is provided. Furthermore, the presence of ARDS, renal failure, hepatic failure, coagulopathy, and UGIH are significantly associated with death.

Lactic acidosis treated with continuous hemodiafiltration and regional citrate anticoagulation.

OBJECTIVE: To evaluate the effectiveness of continuous arteriovenous hemodiafiltration (CAVHD) using citrate as the anticoagulant for the treatment of lactic acidosis in patients with renal failure. DESIGN: Case series with careful monitoring of the clinical course of patients being treated in a medical or surgical ICU. SETTING: University hospital ICU. PATIENTS: Two patients with lactic acidosis are described, along with our experience using CAVHD and citrate in other clinical settings. INTERVENTIONS: CAVHD was used to manage renal failure, while a continuous infusion of citrate was administered to maintain patency of the extracorporeal circuit. MEASUREMENTS: Total and ionized serum calcium concentrations and citrate concentrations were monitored. MAIN RESULTS: CAVHD with citrate as the anticoagulant proved to be a convenient means of managing vascular volume, serum electrolyte concentrations, acid-base balance, and replacement renal function requirements in the setting of severe lactic acidosis, oliguric renal failure, and hemorrhagic diathesis. CONCLUSIONS: CAVHD with citrate as the anticoagulant can be recommended as effective therapy for selected patients, but careful monitoring is needed to avoid serious complications.

Prostacyclin and thromboxane A2 formation is increased in human sepsis syndrome. Effects of cyclooxygenase inhibition.

Arachidonic acid metabolites, especially thromboxane-A2 and prostacyclin, have been shown to be increased in experimental models of sepsis and the adult respiratory distress syndrome (ARDS) and play a major pathophysiologic role. This study was designed to determine if these metabolites are increased in human sepsis syndrome and if inhibition of fatty acid cyclooxygenase affects their formation and their pathophysiologic sequelae. We conducted a double-blind, placebo-controlled trial of ibuprofen (800 mg given rectally every 4 h for three doses) in 30 patients with sepsis syndrome defined by abnormal vital signs, the appearance of serious infection, and at least one major organ failure. Urinary concentrations of the metabolite of thromboxane-A2, 2,3-dinor-TxB2, and prostacyclin, 2,3-dinor-6-keto-prostaglandin F2 alpha, were elevated 10 to 20 times normal and declined to four to five times normal by 12 h after entry in the ibuprofen-treated group and remained elevated in the placebo-treated patients. The urinary concentration of TxB2 and 6-keto-prostaglandin F1 alpha, which reflect renal production of TxA2 and prostacyclin, respectively, were also increased approximately 10-fold over normal and were subsequently decreased by ibuprofen. Coincident with the reduction in metabolite levels, the ibuprofen-treated group, but not the placebo-treated group, experienced a significant decline in temperature, heart rate, and peak airway pressure, and a trend towards more rapid reversal of shock (p = 0.12).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of a LTD4 receptor antagonist in porcine septic shock.

The effect of a selective LTD4 receptor antagonist SK & F104353 was studied in septic pigs anesthetized with isoflurane. Yorkshire pigs (25.2 +/- 2.3 kg) were instrumented and monitored for cardiac output (CO), mean arterial pressure (MAP), systemic vascular resistance (SVR), mean pulmonary arterial pressure (MPAP), pulmonary vascular resistance (PVR), renal artery blood flow (RABF), renal vascular resistance (RVR), arterial PO2, and extravascular lung water (EVLW). Blood samples were also collected for platelet, white blood cell and hematocrit determinations and plasma was assayed for thromboxane (TX) B2. Sepsis was induced by infusion of Pseudomonas aeruginosa (3 x 10(8) CFU%kg/h) for 2 h. Cardiovascular and hematologic data were determined at 30 min intervals for 4 h. Groups were infused with either SK & F104353 (3 mg/kg/h; n = 5) or drug vehicle (n = 6) beginning 15 min prior to infusion with the P. aeruginosa. In the vehicle group beginning at -90 min after sepsis induction, there was a 30 +/- 7% decrease of CO, a 27 +/- 5.0% decrease of MAP, and a 44 +/- 7% decrease of RABF, whereas, MPAP increased to 147 +/- 37% and plasma TXB2 increased from less than 200 pg/ml to 3,049 +/- 367 pg/ml (P less than 0.05). The EVLW and hematocrit increased (P less than 0.05), and the arterial PO2, white blood cell count, and platelet count decreased with the severity of the sepsis. In pigs pretreated with SK & F104353 the MAP and RABF were transiently improved (P less than 0.05), and the decrease in arterial PO2 was delayed.(ABSTRACT TRUNCATED AT 250 WORDS)

Noninvasive estimation of extravascular lung water using bioimpedance.

Currently, accurate measurements of extravascular lung water (EVLW) are obtained using the double dye dilution technique (DD). However, this method is invasive and complicated and has limited its clinical use. The purpose of this study was to develop a noninvasive method for determining changes in EVLW using bioimpedance (BI) and compare these measurements with DD in a model of acute pulmonary injury. Nine adult dogs were anesthetized and instrumented with a pulmonary artery and an EVLW arterial catheter with EVLW-DD and cardiac output calculated from the dye and thermal dilution curves. Eight external electrodes were placed on the thorax and impedance changes were measured by computer. Changes in EVLW-BI were computed as a function of the thoracic volume and impedance. Cardiac output (CO) from BI was obtained by electronically differentiating the bioimpedance signal. EVLW and CO were measured using DD and BI at 0, 15, 30, and 60 min following injection of oleic acid (0.1 cc/kg). Changes in EVLW were correlated over all time periods using DD and BI (r = 0.70, P less than 0.05); however, several impedance EVLW estimates varied greatly from double dilution methods. There was no difference in computed EVLW using DD and BI at 15, 30, and 60 min following oleic acid infusion (P greater than 0.35). CO was significantly correlated using DD and BI (r = 0.81, P less than 0.05). In summary, bioimpedance may hold promise as a noninvasive and continuous means for estimation of EVLW in the critical care setting.

A prospective comparison of IMV and T-piece weaning from mechanical ventilation.

Two hundred (200) consecutive medical and surgical patients requiring mechanical ventilation were entered into a prospective randomized trial of weaning by either intermittent mandatory ventilation (IMV) or T-piece. Patients in these groups were of similar age and sex and had the same total ventilation time (TVT). The study design provided equal time for each weaning mode after specific criteria for oxygenation and ventilation were satisfied (PaO2 greater than 55 mm Hg on FIO2 less than 0.5; VE less than 12 L/min and two of the following four parameters: MVV greater than 2 VE, VT greater than 5 ml/kg, FVC greater than 10 ml/kg, NIF less than or equal to -20 cm H2O). Of the original 200 patients 165 were entered into the weaning phase; 35 patients were withdrawn prior to weaning due to the discretion of the attending physician or protocol error. Weaning time was not different between the IMV (5.3 +/- 1.2 h, mean +/- SEM) and T-piece groups (5.9 +/- 1.4 h, p = NS). Of the 165 patients, 155 (93 percent) were weaned successfully by protocol, 79 in the IMV and 76 in the T-piece group. Of 155 patients, 136 (88 percent) were weaned on the first attempt by protocol. Of the 19 who were not weaned, 11 were weaned successfully on the second and five on the third trial; three patients required three-day weans. We conclude that clinically stable patients who require short-term mechanical ventilation and meet standard bedside weaning criteria can be weaned efficiently by protocol using either IMV or T-piece techniques.