Problem orientation is a new approach to surgical education.

BACKGROUND: There is increasing interest in educational methods that are loosely aggregated under the title of problem-based learning (PBL), but it remains unclear whether PBL is as successful as its conventional predecessor in transmitting factual information. MATERIALS AND METHODS: The authors designed and implemented a PBL curriculum for a third-year surgical clerkship, then prospectively compared that technique with the conventional format. Each student's subject-related knowledge was assessed with a specifically tailored 195-question written exam and correlated with National Board of Medical Examiners shelf exams. Student and faculty responses to the technique were also sought and tabulated. RESULTS: Student and faculty responses to PBL were uniformly positive. We were unable, however, to demonstrate effects on our evaluation instruments. Neither individual student performance nor grouped scores differed based on the mode of presentation. CONCLUSION: A PBL curriculum generates both student and faculty enthusiasm. Unfortunately, this does not translate into more efficient transmission of knowledge.

Penetrating and blunt injuries of the esophagus.

Though uncommon, the incidence of esophageal injury from external trauma is increasing in frequency and requires a thorough knowledge of the principles of esophageal surgery in general and familiarity with the options for repair of both the different anatomic locations of injury and the various types of injuring agents. Such knowledge and experience will avoid the potential for complications such as those described centuries ago by Richard Wiseman in the young man who impaled himself on his toy sword.

Boerhaave's syndrome and barogenic injuries of the esophagus.

Herman Boerhaave clearly elucidated the pathology of barogenic esophageal perforation during the 18th century by describing the sad and fatal case of Baron John von Wassenauer. Although the science of the time had no treatment and surgery was considered a fool's venture, Boerhaave's description has stood the test of time and set the stage for modern surgical repair and treatment. The expeditious diagnosis, aggressive early repair, and vigilant attention to drainage of esophageal perforations in the 20th century all reduce the morbidity and are essential steps to obtaining the best outcome. Today, survival of barogenic esophageal perforation requires the surgeon to have the clarity of Boerhaave's observation of symptoms and to make use of modern surgical techniques to assure the patient's recovery from Boerhaave's syndrome.

Bradycardia following carotid endarterectomy.

This study was performed to determine whether bradycardia complicates the postoperative course of patients undergoing carotid endarterectomy (CEA). The records of 216 patients undergoing 233 CEAs over a 2-year period were reviewed. Patients were divided into two groups based on their lowest Surgical Intensive Care Unit (SICU) heart rate (HR). Those with HR < 60 were in the Bradycardic (BRADY) group and those with HR > or = 60 were in the Non-Bradycardic (NON-BRADY) group. One hundred and sixteen patients developed bradycardia, with a mean (+/- SEM) HR of 51.1 +/- 0.5, compared with 117 NON-BRADY patients with a mean HR of 70.6 +/- 0.9 (P < 0.0005). There were no significant differences between the groups in age, use of cardioactive drugs, SICU severity of illness, or length of SICU stay. The systolic blood pressure for BRADY patients averaged 144 +/- 2.2 on admission and 144 +/- 2.2 (P = NS) in the SICU, while that of NON-BRADY patients rose from 143 +/- 2.3 on admission to 156 +/- 2.5 (P = 0.001). Fifty-four patients receiving a second CEA had a SICU HR not significantly different from those patients undergoing a first CEA. Of 17 patients who underwent bilateral CEAs during the study period, SICU HRs averaged 65.1 +/- 3.7 after the first procedure and 64.7 +/- 3.6 after the second (P = NS). The authors conclude that bradycardia following CEA is a frequent but benign postoperative finding that does not affect outcome, cause significant hypotension, or prolong the SICU stay.

Surgical intensive care in the nonagenarian. No basis for age discrimination.

OBJECTIVE: To investigate the effect of extreme age on outcome from surgical intensive care. DESIGN: Prospective data collection. SETTING: A 20-bed noncardiac surgical intensive care unit (SICU) that admits 2200 patients per year from a 1201-bed tertiary medical center. PATIENTS: Nonagenarians were compared with patients under 90 years of age over a 33-month period. Seven patients over age 100 years and 77 nonsurgical patients were excluded. MAIN OUTCOME MEASURES: Mortality and length of stay were determined for both the SICU and the entire hospitalization. The nonagenarian and younger groups were stratified by severity of illness using the first-day Simplified Acute Physiology Score (SAPS). RESULTS: One hundred forty nonagenarian patients (mean +/- SE age, 92.1 +/- 0.2 years) were compared with 5652 younger patients (mean age, 60.1 +/- 0.3 years). The mean SAPS of 11.1 for nonagenarian patients was significantly higher than the SAPS of 8.6 for younger patients (P < .001). Mortality in the SICU was 4.3% for nonagenarian patients vs 2.3% for younger patients (P = .13). SICU mortality rose with increasing SAPS in both groups, but there was no significant difference between nonagenarian and younger patients for any SAPS group. Hospital mortality differed significantly, with 17.1% for nonagenarian patients and 5.3% for younger patients (P < .001). Hospital and SICU length of stay did not differ significantly between the groups. CONCLUSIONS: Nonagenarians do not differ from younger SICU patients in survival from SICU care, although hospital mortality is greater in nonagenarians. Age alone should not be used to make decisions about the utility of SICU care for the elderly. Outcome correlates better with severity of illness, and the measure is valid in young and old alike.

Neonatal survival during a 2,500-mile flight.

Neonatal respiratory failure, no matter what the cause, may not always respond to standard mechanical ventilation techniques. Extracorporeal membrane oxygenation has emerged over the last 15 years as an adjunct to the treatment of these babies with a greater than 80% survival nationwide. Limited resources and personnel costs can be prohibitive, forcing regionalization of extracorporeal membrane oxygenation (ECMO) centers. Geographic distance from a center should not limit its potential application, however. Familiarity with the technique, early application of the modality and the availability of medical air transport, allows for referral and transfer of neonates over great distances with excellent results and outcomes. We present a case of respiratory failure in a neonate transported 2,500 miles for ECMO therapy with an excellent outcome and a rapid return home.

Glucose intolerance in critically ill surgical patients: relationship to total parenteral nutrition and severity of illness.

The authors evaluated the relative influence of severity of illness and total parenteral nutrition (TPN) on glucose intolerance in critically ill surgical patients. Records of TPN administration, serum glucose measurements, and the simplified acute physiology score (SAPS) were extracted from the surgical intensive care unit (SICU) and hospital clinical information systems (CIS) for all patients admitted to the SICU from October 1, 1989 through March 31, 1990. Critical hyperglycemia was defined as glucose > 400 mg/dL and critical hypoglycemia as < 40 mg/dL. During the study period, 1,129 patients received 3,054 days of care, including 88 patients who received 705 days of TPN. Of 4,985 glucose determinations performed during the study period, 48 (0.96%) were critically abnormal. Critical hyperglycemia occurred in 1.7 per cent of blood samples from TPN patients, compared to 0.7 per cent in non-TPN patients (P < 0.005). However, the mean admission and daily and maximum severity of illness scores were significantly higher in TPN patients compared to non-TPN patients (all P < 0.0005). Mean glucose levels rose with increasing SAPS in both TPN and non-TPN patients. When stratified by severity of illness, TPN patients did not have significantly higher glucose levels than non-TPN patients except for the SAPS = 15 category. The authors conclude that the glucose intolerance noted in critically ill TPN patients reflects their underlying severity of illness rather than TPN administration per se.

Decreasing transfusion exposure risk during extracorporeal membrane oxygenation (ECMO).

Extracorporeal membrane oxygenation (ECMO) is a lifesaving therapy for neonatal pulmonary hypertension but carries a significant risk for transfusion-related complications. Packed red blood cell (PRBC) and platelet exposure were quantified and reviewed in 17 ECMO survivors prior (Group I, n = 9) and subsequent to (Group II, n = 8) changes in transfusion protocols. Blood product requirements included ECMO circuit priming, maintenance of haematocrit > 0.40 or platelet count > 50 x 10(9)/l, and colloid volume expansion. Group I was exposed to 13.8 +/- 10.2 (x +/- SD) different PRBC units. In Group II, multiple transfusions from single donor units decreased exposure 71% to 3.9 +/- 0.7 units (P < 0.05). Decreases in blood withdrawn (11%) and transfusion volume (7%) were coincident with a 15% reduction in mean bypass time. Platelet volume transfusion decreased from 159 +/- 213 to 93 +/- 64 ml using volume-reduced platelet packs. Total transfusion exposure decreased 59% from 20.8 +/- 17.8 units to 8.6 +/- 2.4 donor units. No transfusion complications occurred during the aggregate 1,926 h on bypass. We conclude that neonates on ECMO have a significant transfusion exposure risk increasing with prolonged duration of ECMO therapy. In addition we noted that concentrated platelet packs decreased transfusion volume by 41%, and multiple PRBC transfusions from single donor units decreased donor exposure by 71% while both strategies decreased the overall transfusion exposure risk by 59%.

Impact of ICU nosocomial infections on outcome from surgical care.

The authors studied the impact of intensive care unit (ICU) acquired nosocomial infections on surgical patients stratified by severity of illness before acquisition of the infection. Data were analyzed from 2,122 consecutive patients admitted to a 20 bed surgical intensive care unit (SICU) from January 1, 1988 to December 31, 1988. The simplified acute physiology score (SAPS), a measure of illness severity that correlates with mortality, was calculated for all patients on their first SICU day. Ninety-seven nosocomial infections from various sites were documented in 54 patients. Patients who acquired a nosocomial infection were significantly more ill upon admission to the SICU than patients who did not acquire such an infection (control patients). Stratified by admission severity of illness, patients acquiring one or more nosocomial infections had a significantly longer SICU stay, averaging 25.3 days compared to 2.3 days in control patients (P less than 0.001). Hospital stay was also significantly increased at 59.9 days, compared to 15.0 days in control patients (P less than 0.001). However, the overall mortality rate for patients developing nosocomial infections was significantly higher than control patients only in the middle range of admission SAPS measurements. The authors found that the monthly incidence of isolates of Xanthomatous maltophilia, a multiply-resistant nosocomial organism, reflected the overall incidence of nosocomial infections in the SICU. They observed a decline in the number of new X. maltophilia isolates and nosocomial infections concomitant with the introduction of gown and glove contact isolation procedures. The authors conclude that nosocomial infections in the SICU setting are directly related to increased patient morbidity and mortality depending, in part, on severity of illness upon admission.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary edema and fluid mobilization as determinants of the duration of ECMO support.

The physiological variables that govern recovery of pulmonary function during neonatal extracorporeal membrane oxygenation (ECMO) remain poorly understood. We hypothesized that pulmonary hypertension (PHN) resolves soon after starting ECMO and that neonatal weight gain, pulmonary edema, and fluid mobilization are major determinants of recovery of pulmonary function and the ability to decrease ECMO support. To evaluate this, 17 consecutive neonates requiring ECMO for severe respiratory failure were reviewed. PHN was studied by daily echocardiography to assess the direction of ductal shunting. To evaluate fluid flux, pulmonary function, and edema during ECMO, we measured body weight, urine output, and ECMO flow every 12 hours. To evaluate pulmonary edema, serial chest radiographs obtained every 12 hours were randomly reviewed and scored by two radiologists with a semiquantitative chest radiograph index score (CRIS). By 25% of bypass time, PHN had resolved in all patients. However, at that time, weight had increased to 9.16% +/- 1.78% above birth weight, and the CRIS was 44% worse than the value just prior to ECMO. From 25% time on bypass, as urine output increased, patient weight and CRIS progressively decreased, allowing ECMO support to be weaned. At the time of discontinuation of ECMO support, weight had decreased to 2.0% +/- 1.3% above birth weight, and urine output remained steady at 3.0 +/- 0.3 mL/kg/h. Within 24 hours of stopping ECMO, the CRIS showed a 58% improvement compared to maximal scores during ECMO. We conclude that PHN decreases early in ECMO and that edema and its mobilization are important determinants of the improvement in pulmonary function and duration of ECMO.(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical correction of hydrothorax from diaphragmatic eventration in children on peritoneal dialysis.

Continuous ambulatory peritoneal dialysis (CAPD) is frequently used in the pediatric age group for reversible and end-stage renal failure. Most pediatric patients tolerate this therapy with few complications. Approximately 2% of children, however, develop massive unilateral hydrothorax. This major complication usually results in the discontinuation of peritoneal dialysis in all forms and the institution of hemodialysis. Occult diaphragmatic defects account for most adult and pediatric patients who develop this complication. Three pediatric patients receiving CAPD complicated by massive hydrothorax are described. All patients were successfully treated by thoracotomy and repair of the diaphragmatic eventration with an immediate return to CAPD. This is the first report of successful therapy of this kind in children. A review of the cause, diagnosis, and treatment of massive hydrothorax developing during CAPD therapy is presented.

Quality assurance and utilization assessment: the major by-products of an ICU clinical information system.

In 1985 we developed a method of automatically extracting indices of severity of illness and intensity of interventions from CIS charts daily. These indices, when combined with outcome measures such as length of stay and mortality, provide a powerful new tool for quality management in the ICU. In this paper we describe our ICU's severity adjusted survival rates as compared to internationally publish norms. In addition we provide a detailed analysis of glucose levels in our ICU, which suggests that glucose control in surgical ICU patients is more closely related to measured severity of illness than administration of intravenous alimentation per se. CIS extracted indices provide a new basis for continuous quality measurement and improvement in the ICU.

Deleterious effects of testicular venous occlusion in young rats.

To determine the differences between testicular arterial and venous obstruction, the spermatic artery or vein, or both, were occluded for varying periods of time in young rats. Two months later, at the conclusion of the study, the testes were examined. Histologic degeneration after vascular obstruction was graded by a modified Johnsen's tubular biopsy score (TBS). The testicular concentrations of enzymes (lactic dehydrogenase and sorbitol dehydrogenase), known to decrease with testicular injury, were measured. TBS and seminiferous tubule diameter (STD) were found to decrease significantly after two hours of vascular occlusion and were similar regardless of whether the obstruction was produced by occlusion of arterial inflow or venous drainage, or both. Testicular concentration of enzymes decreased significantly after permanent ligation of the spermatic artery and vein, but decreased minimally when the vascular obstruction lasted less than 120 minutes. Testicular injury produced by venous occlusion was equally severe and occurred as rapidly as injury produced by arterial or combined arteriovenous occlusion. No significant injury was noted in the contralateral testes in any group.

Surgical management of islet cell dysmaturation syndrome in young children.

Islet cell dysmaturation syndrome (ICDS) encompasses the causes of infantile hyperinsulinemic hypoglycemia histologically described as islet cell hyperplasia, pancreatic adenomatosis and nesidioblastosis. Eleven infants underwent 14 pancreatic resections for ICDS from 1965 to 1990 at the University of California at Los Angeles Medical Center for severe hypoglycemia unresponsive to medical therapy. Seizures were the presenting symptoms of hypoglycemia in eight infants. Six patients had nesidioblastosis, four had islet cell hyperplasia and one patient had an adenoma with histologically normal pancreatic islet cells. Four neonates underwent 80 per cent pancreatic resection; three with nesidioblastosis required reoperation (90 to 95 per cent resection). Four older infants underwent 80 per cent pancreatic resection but required diazoxide for less than six months postoperatively. Three infants underwent 90 to 95 per cent pancreatic resection. None have required reoperation or postoperative medications. All infants are normoglycemic without pancreatic exocrine insufficiency and none had postoperative complications. Five infants had preoperative neurologic impairment, with three having severe retardation; all showed some improvement postoperatively, but only one infant now has normal findings on neurologic examination. Early diagnosis and aggressive surgical resection should minimize neurologic complications of the ICDS.

Extracorporeal membrane oxygenation in the treatment of neonatal respiratory failure.

We report 18 consecutive neonates with severe respiratory failure due to pulmonary hypertension treated with extracorporeal membrane oxygenation. Extracorporeal membrane oxygenation was begun at 52 +/- 36 hours of age with an arterial partial pressure of oxygen (PO2) of 36 +/- 14 mm Hg despite maximal pharmacologic and ventilator support (inspired fraction of oxygen [FiO2], 0.99 +/- 0.03; respiratory rate, 98 +/- 31/min; and positive inspiratory pressure, 54 +/- 11 cm of water). With initial flows of 130 +/- 17 mL/kg per minute, ventilator settings were reduced to the following: FiO2, 0.30; respiratory rates, 15/min; and positive inspiratory pressure, 24 cm of water. Support using extracorporeal membrane oxygenation was gradually reduced to 22% of initial flows and arterial blood samples showed pH 7.48 +/- .05, PO2 of 106 +/- 27 mm Hg, and PCO2 of 36 +/- 5 mm Hg just prior to decannulation. After 107 +/- 45 hours, extracorporeal membrane oxygenation was stopped and infants were extubated 61 +/- 53 hours (median, 46 hours) afterward. There was one death (94.4% survival rate); all survivors were discharged and underwent a follow-up examination at 1 to 27 months of age. Complications included two intracranial hemorrhages (one death and one asymptomatic), one patent ductus arteriosus requiring ligation on extracorporeal membrane oxygenation, and chronic lung disease in one patient. In selected neonates, extracorporeal membrane oxygenation allows for resolution of pulmonary hypertension, results in improved survival, and is associated with a low incidence of chronic lung disease. Extracorporeal membrane oxygenation should be considered in the treatment of severe respiratory failure.

Early effects of colectomy and endorectal pullthrough operation on biliary lipid composition.

In order to determine the effects of total colectomy and endorectal pullthrough with ileal reservoir (ERP) on biliary lipid composition in the early postoperative period, gallbladder bile of dogs was examined after biliary cannulation alone (control); biliary cannulation and colectomy with ileorectal anastomosis (IRA); and biliary cannulation, colectomy with mucosal proctectomy, and ERP. Bile collected from 3 to 6 weeks postoperation was analyzed for total bile acids, cholesterol, phospholipids, bilirubin, and calcium concentrations. Cholesterol saturation was calculated. Serum collected over the same period was analyzed for electrolytes and liver function tests. There was no evidence of sludge or gallstones post-operatively in any animal. Significant decreases in total bile acids, phospholipids, and calcium concentrations were noted in the bile of the IRA group when compared to the bile of the controls (P less than 0.05) and in total bile acids, cholesterol, phospholipids, and calcium in ERP vs controls (P less than 0.05). Moreover, all three biliary lipids and calcium were significantly decreased in ERP animals compared to those in the IRA group (P less than 0.05). No change in cholesterol saturation was noted between any of the three groups. Other than an increase in alkaline phosphatase concentrations compared to preoperative levels (P less than 0.05) which was noted in all groups, no significant changes were noted in serum parameters. We conclude that during the early postoperative period, ERP causes a significant decrease in gallbladder bile concentrations of total bile acids, cholesterol, phospholipids, and calcium which cannot be explained by colectomy alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood flow in sequential vein grafts.

In 69 patients undergoing coronary artery bypass grafting for complete coronary revascularization, blood flow was measured in 140 grafts with 243 distal anastomoses (3.52 bypasses/patient). Total blood flow in single grafts and double and triple sequential grafts did not differ significantly, although mean distal flow decreased successively with single (85 cc/min), double (51 cc/min), and triple (32 cc/min) sequential grafts. Total myocardial flow did not vary significantly regardless of the number of grafts placed. Flow measurements in patients with double sequential grafts showed greater than 20% overlay in flow between the two distal anastomoses. The data suggest significant but incomplete collateral supply between adjacent coronary beds consistent with the concept of any individual area of myocardium being a capacitance bed supplied in part by a number of adjacent coronary branches.