Physician partnering: a provider network primer.

The face of health care is changing daily due to pressures brought about by dissatisfied consumers, physicians, and employers. The authors of this article believe that the only way to bring about a better health care system is for physicians to take back the administration of the medical profession from the insurers. Physicians must take the financial risks necessary to innovate a medical system that will benefit themselves, their patients, and their patients' employers. This article presents the basic business concepts needed to establish physician provider networks (PPNs) as well as the benefits and pitfalls of the various types of associations into which a PPN can enter. Clearly, the future will belong to those physicians who have the foresight to invest their talents and their finances in the business aspects of managed care.

Provider service organizations: a method to establish physician prerogatives.

The face of health care is changing daily because of pressures brought about by dissatisfied consumers, physicians, and employers. We believe that physicians need to take back from insurers the administration of the medical profession. Physicians must assume the financial risks necessary to create a medical system that will benefit themselves, their patients, and their patient's employers. This article presents the basic business concepts needed to establish Provider Service Organizations (PSOs) as well as the benefits and pitfalls of the various types of associations into which a PSO can enter. Clearly, the future belongs to those physicians who have the foresight to invest their talents and their finances in the business aspects of managed care.

Zinc-bis-histidinate preserves cardiac function in a porcine model of cardioplegic arrest.

BACKGROUND: We examined the ability of zinc-bis-histidinate to preserve postarrest myocardial function when added to a standard crystalloid cardioplegic solution. METHODS: Domestic pigs (35 to 50 kg) on left-sided cardiopulmonary bypass were subjected to 90 minutes of regional ischemia followed by 60 minutes of hypothermic cardioplegic arrest induced by antegrade infusion of 20 mL/kg cold St. Thomas' #2 cardioplegic solution with or without 100 mumol/L of zinc-bis-histidinate and maintained by infusion of 10 mL/kg of the same every 20 minutes. During reperfusion function was assessed at 1 and 3 hours over increasing preloads using the right-sided bypass method. RESULTS: At roller pump flows up to 2,000 mL/min, stroke work index-end-diastolic pressure curves were significantly (p < 0.05) higher and shifted to the left in treated hearts. In a series of pigs, echocardiography was used to determine end-diastolic and end-systolic volumes. At roller pump flows up to 3,500 mL/min, end-systolic pressure-end-systolic volume curves were significantly higher and shifted to the left in treated hearts. Left ventricular ejection fraction, fractional shortening, stroke volume, and cardiac output were significantly (p < 0.05) higher in treated hearts. Electron microscopy revealed that mitochondria in tissue not at risk appeared more swollen in control hearts. CONCLUSIONS: The results of this study support the conclusion that zinc-bis-histidinate is effective as a myocardial preservative when added to a crystalloid cardioplegic solution.

A dynamic method for setting roller pumps nonocclusively reduces hemolysis and predicts retrograde flow.

In general, roller pumps are set almost occlusively despite evidence that nonocclusive settings cause less hemolysis. Almost-occlusive settings are used because of the concern that forward flow would not be accurately known if retrograde flow were allowed to occur through a nonocclusive gap. This article presents a dynamic method for setting roller pumps nonocclusively that overcomes the many difficulties of the "drop method" for setting occlusion. Studies were conducted to determine the effect of nonocclusive settings on pump flow and hemolysis generated; the results suggest that roller pumps can and should be set more nonocclusively than is the currently accepted standard to reduce pump related hemolysis without greatly affecting pump performance. The dynamic method allows retrograde flow to be easily predicted and corrected with an increase in pump speed.

A prospective randomized study of abdominal aortic surgery without postoperative nasogastric decompression.

Nasogastric decompression following abdominal aortic aneurysmectomy or bypass, for 3-4 days, is a routine part of postoperative care in many centers. A prospective randomized study of 80 patients undergoing abdominal aortic surgery was performed in order to determine the necessity of prolonged nasogastric decompression. Patients were divided evenly between removal of the nasogastric tube upon tracheal extubation and retention of the tube until the passage of flatus. Preoperative risk factors, aortic cross-clamp time, estimated blood loss, length of procedure, length of intensive care unit stay, numbers of days with nasogastric tube, number of days until clear liquid and regular diets commenced, and the length of hospital stay were recorded for all patients. There were no significant differences in any of the measured variables between the two groups. The length of hospital stay was similar in both groups and three patients in each group required a nasogastric tube or reinsertion of one. In conclusion, the routine postoperative use of nasogastric tubes for abdominal aortic procedures is unnecessary.

Zinc supplementation enhances the effectiveness of St. Thomas' Hospital No. 2 cardioplegic solution in an in vitro model of hypothermic cardiac arrest.

The present study was done to assess the effectiveness of a zinc-supplemented cardioplegic solution in an in vitro model of hypothermic arrest. Isolated hearts were perfused in the nonworking mode. All hearts were subjected to 2 hours of hypothermic arrest, at 10 degrees C, followed by 60 minutes of recovery. In protocol 1, arrest was initiated with infusion of cardioplegic solution with or without 30 mumol/l zinc for 5 minutes, which was then reinfused for 5 minutes every 15 minutes during arrest. In protocol 2, arrest was initiated with infusion of cardioplegic solution with or without 40 mumol/L zinc for 10 minutes. Cardioplegic solution (without zinc) was then reinfused for 5 minutes before the hearts were rewarmed. In protocol 1 hearts, peak postischemic left ventricular developed systolic pressure was 106 +/- 5 mm Hg and 80 +/- 3 mm Hg in zinc-treated versus control hearts, respectively (p < 0.05 by repeated-measures analysis of variance). In protocol 2 hearts, recovery of postischemic left ventricular developed systolic pressure peaked at 74 +/- 4 mm Hg and 46 +/- 8 mm Hg in zinc-treated and control hearts, respectively (p 0.05, repeated-measures analysis of variance). Similar effects were observed for the left ventricular rate of relaxation (p < 0.05, repeated-measures analysis of variance). Except for some minor effects, lactate dehydrogenase release was not affected by zinc supplementation. The present study demonstrates that zinc supplementation further enhances the normally observed preservation of postarrest cardiac function and suggests possible clinical utility for this metal as an additive to standard crystalloid cardioplegic solutions.

Reduced length of stay following carotid endarterectomy under general anesthesia.

BACKGROUND: The widespread use of diagnosis-related groups has led to a significant reduction in the length of hospital stay following many surgical procedures. In light of this, an examination of early discharge following carotid endarterectomy under general anesthesia was undertaken. PATIENTS AND METHODS: A prospective study of 72 patients was conducted, in which the workup was done on an outpatient basis, admission took place on the same day as surgery, and patients were discharged home on the day after carotid endarterectomy. RESULTS: There were no strokes or deaths following carotid endarterectomy, and only two transient ischemic attacks occurred. In 88% of the cases, discharge was possible on the first postoperative day. CONCLUSIONS: Early discharge following carotid endarterectomy under general anesthesia is safe and cost effective.

Aortic dissection: rupture into right ventricle and right pulmonary artery.

Rupture of an acute ascending aortic dissection into a surrounding cardiac chamber or pulmonary artery is an uncommon occurrence, and is often only diagnoses post mortem. Although fistulization (aortopulmonary and aorta-right atrial) after acute aortic dissection has been well documented in the literature, acute aortic dissection fistulizing into both the right ventricle and pulmonary artery has not. We report on a 75-year-old woman who presented with an acute ascending aortic dissection with both aortopulmonary and aorta-right ventricular fistulas who underwent repair and had long-term survival.

A prospective randomized comparison of Dacron and polytetrafluoroethylene aortic bifurcation grafts.

BACKGROUND: The purpose of this study was to compare the long-term results of Dacron and polytetrafluoroethylene (PTFE) aortic bifurcation grafts in a prospective randomized manner. METHODS: Sixty patients with aortoiliac occlusive disease were randomized to receive Dacron or PTFE bifurcation grafts. Preoperative risk factors, perioperative blood loss and fluid requirements, and postoperative complications were compared. A mean follow-up of 57 months was achieved. RESULTS: The immediate postoperative morbidity and mortality rates were similar in the two groups, and the long-term complications were low in number and comparable. The cumulative patency rate for Dacron graft limbs was 86% versus 95% for PTFE graft limbs. CONCLUSIONS: No significant differences were noted between the results achieved with Dacron and PTFE aortic bifurcation grafts.

Zinc improves postischemic recovery of isolated rat hearts through inhibition of oxidative stress.

We studied the cardiac protective qualities of zinc in the postischemic isolated rat heart. Hearts, perfused with Krebs-Henseleit buffer with or without zinc-bis-histidinate, were subjected to 20 min of "no-flow" normothermic global ischemia. Pre- and postischemic treatment with 0, 10, 20, or 30 microM zinc resulted in concentration-dependent enhancement of postischemic function as evidenced by decreased end-diastolic pressure (37 +/- 3, 25 +/- 5, 17 +/- 5, and 8 +/- 2 mmHg, respectively) and increased recovery of developed systolic pressure (41 +/- 6, 59 +/- 17, 76 +/- 18, and 87 +/- 16 mmHg, respectively) and maximum rate of rise in pressure (+dP/dtmax; 823 +/- 141, 1,413 +/- 396, 1,700 +/- 450, and 2,157 +/- 407 mmHg/s, respectively) as well as decreased lactate dehydrogenase efflux from the hearts (peak: 1,002%, 840%, 580%, and 440%, respectively). Only preischemic treatment resulted in an intermediate protective effect, whereas treatment starting at reperfusion worsened postischemic damage. In hearts perfused with zinc throughout the experiment, prolongation of the preischemic treatment interval further enhanced postischemic recovery. With the use of salicylate as a trap for .OH, it was determined that zinc virtually eliminated the early postischemic "burst" of this species normally observed in this preparation. Atomic absorption studies demonstrated that hearts treated with 30 microM zinc contained 27% less copper than control hearts by the end of the reperfusion period. In control hearts, electron microscopy revealed swollen mitochondria with marked loss of inner matrix density, whereas morphology of postischemic zinc-treated hearts was essentially normal. These studies indicate that zinc possesses cardiac cytoprotective qualities and support the concept that this metal can decrease .OH formation by affecting copper reactivity.

The effects of pressure and flow on hemolysis caused by Bio-Medicus centrifugal pumps and roller pumps. Guidelines for choosing a blood pump.

Two Bio-Medicus BP-50 centrifugal pumps and two roller pumps were tested simultaneously with porcine blood at 21 degrees +/- 1 degree C in four in vitro circuits to determine the effect of four combinations of flow and pressure conditions on blood damage. Flows of 300 ml/min (1/4-inch inner-diameter tubing in the roller pump) and 1775 ml/min (1/2-inch inner-diameter tubing in the roller pump) and pressure differences across the pump (delta P = outlet pressure--inlet pressure) of 215 mm Hg (n = 6) and 345 mm Hg (n = 5) were examined. The index of hemolysis (milligrams plasma hemoglobin per 100 L blood pumped) for the BP-50 pump was higher at a flow of 300 ml/min than at a flow of 1775 ml/min (p < 0.0002). At 300 ml/min, the index of hemolysis for the BP-50 pump tended to be higher at 345 mm Hg than at 215 mm Hg (mean +/- standard error of the mean, 135 +/- 22 versus 88 +/- 9, p = 0.059). At 1775 ml/min, there was no difference in the index of hemolysis for the BP-50 pump between 215 and 345 mm Hg (37 +/- 7 versus 29 +/- 5, p = 0.32). With the roller pump, the index of hemolysis was higher at a flow of 300 ml/min than at a flow of 1775 ml/min (p < 0.036), but there was no difference in the indexes of hemolysis between 215 and 345 mm Hg at 300 ml/min (60 +/- 9 versus 61 +/- 11, p = 0.93) or at 1775 ml/min (40 +/- 6 versus 36 +/- 6, p = 0.61). Comparison between the two types of pumps showed that the index of hemolysis was significantly higher for the BP-50 than for the roller pump at a flow of 300 ml/min and a delta P of 215 mm Hg (88 +/- 9 versus 60 +/- 9, p = 0.009), as well as at a flow of 300 ml/min and a delta P of 345 mm Hg (135 +/- 22 versus 61 +/- 11, p = 0.001). At a flow of 1775 ml/min, there was no difference in the index of hemolysis between the two pumps at either pressure condition.(ABSTRACT TRUNCATED AT 250 WORDS)

The evaluation and management of known or suspected stones of the common bile duct in the era of minimal access surgery.

Laparoscopic cholecystectomy (LC) has rapidly become the procedure of choice for symptomatic cholelithiasis. The perioperative diagnosis and modern treatment of suspected stones of the common bile duct (CBD) remains controversial. A database of 573 patients undergoing LC was compiled during an 11 month period. Sixty-seven patients (47 females, 20 males) (13 percent) were suspected of having CBD stones based upon clinical, laboratory and roentgenographic evidence. Fifty-two patients underwent endoscopic retrograde cholangiopancreatography (ER-CP) (45 preoperative and seven postoperative). Seventeen patients were studied with intraoperative cholangiogram (IOC). The indications for cholangiography (either ERCP or IOC) included pancreatitis (group 1), clinical history suggestive of CBD stones, but normal preoperative liver function tests (LFT) (group 2), cholangitis (group 3), grossly abnormal LFT (group 4) and dilated CBD (greater than 7 millimeters on sonogram) (group 5). The incidence of CBD stones was three of 14 (21 percent) in group 1, six of 20 (30 percent) in group 2, two of three (67 percent) in group 3, 16 of 26 (62 percent) in group 4 and two of four (50 percent) in group 5. Overall, 29 patients (23 females and six males) had stones retrieved from the CBD. Of the 52 ERCP, 20 endoscopic sphincterotomies were performed for documented CBD stones. Of the group that had pre-LC ERCP, three (6 percent) ultimately required an open procedure. There were three instances of post-ERCP pancreatitis (6 percent) and ERCP was not able to opacify or clear the CBD in four instances. Seven patients had postoperative ERCP with successful retrieval of retained CBD stones (100 percent). Of the 17 IOC, eight were positive--two patients underwent laparoscopic clearance of the CBD and six required conversion to an open procedure. There were no deaths or extensive complications. Total and direct bilirubin, alkaline phosphatase and serum glutamic pyruvic transaminase were independently related to the presence of a CBD stone, while demographic data, past medical history, preoperative symptoms, leukocyte count, vital signs, amylase, serum glutamic-oxalacetic transaminase nuclear scintigraphic visualization of the duodenum or size of CBD on sonography, were not. No patient with biliary pancreatitis had CBD stones without abnormalities in the LFT or the preoperative sonogram. ERCP is a useful technique to clear the CBD pre-LC. However, ERCP in patients with biliary pancreatitis, but otherwise normal preoperative tests, has a low yield. In this group of patients, IOC is an appropriate alternative to pre-LC ERCP.

Detection of alkoxyl and carbon-centered free radicals in coronary sinus blood from patients undergoing elective cardioplegia.

Confirmation of the involvement of free radicals in postischemic injury in human heart has been elusive. The present study was performed to determine the presence of free radicals in coronary sinus blood from patients undergoing elective open heart surgery and cardioplegia. Six patients who were scheduled for nonurgent elective open heart surgery were used in this study. Coronary sinus blood samples were withdrawn at 1, 3, 5, 10, 15, 20, and 25 min in post-cross-clamp and immediately mixed with isosmotic alpha-phenyl-tert-butylnitrone (PBN) and then centrifuged to obtain plasma. Plasma samples were extracted with toluene and analyzed using electron spin resonance (ESR) spectroscopy. We observed ESR spectra consistent with the formation of alkoxyl and carbon-centered radical adducts of PBN (aN = 13.6 G, a beta H = 1.9 G, and aN = 14.1 G, a beta H = 4.2 G) in six of six patients. We obtained complete free radical production time courses during reperfusion from five patients, and all demonstrated a biphasic profile with an initial burst from 5 to 10 min followed by a second maxima at 25 min. Total PBN-adduct production during reperfusion increased in patients subjected to longer aortic cross-clamp times (global ischemia). These data demonstrate that postcardioplegia free radical production is detectable in coronary sinus blood using an ex vivo spin-trapping technique and that the extent of formation may be related to the severity of ischemia.

Mediatory role of copper in reactive oxygen intermediate-induced cardiac injury.

In this report the mediatory role of copper in cardiac injury produced by reactive oxygen intermediates was examined. Isolated rat hearts were perfused with Krebs-Henseleit buffer containing 0.25 mM ascorbate plus varying concentrations of copper-bis-histidial for up to 60 min. Using salicylate as a probe, OH generation by this system was demonstrated. Copper or ascorbate alone had minimal effect on cardiac function as determined by heart rate, coronary flow, left ventricular systolic pressure development, end diastolic pressure and +/- dP/dtmax. Copper, from 0.5 microM to 20 microM, and ascorbate, 0.25 mM, resulted in concentration-dependent decreases in all of the experimental variables. Treatment with 5 or 20 microM copper resulted in complete loss of cardiac function within 40 and 30 min, respectively. By 30 min, 5 microM copper had resulted in increased end diastolic pressure to greater than 40 mmHg. By 60 min, perfusion with 1 microM copper resulted in almost 100% loss of function and end diastolic pressure greater than 25 mmHg. Copper, 0.5 microM, also decreased cardiac function, but to a lesser degree. Catalase, 100 units/ml, was effective in preventing the copper-ascorbate induced cardiac damage while superoxide dismutase, 25 units/ml, was ineffective. Observations by light and electron microscopy demonstrated patchy regions with vacuolization corresponding to swollen mitochondria. These results clearly demonstrate that copper-catalyzed redox reactions can induce cardiac injury via a mechanism which appears to be related to the production of OH.

Recent advances in the role of reactive oxygen intermediates in ischemic injury. I. Evidence demonstrating presence of reactive oxygen intermediates; II. Role of metals in site-specific formation of radicals.

This article has attempted to bring the reader up to date on advances in selected facets of the area of reactive oxygen intermediate-induced ischemic injury. Specifically, we have discussed the more recent reports that provide evidence for the presence of these species in reperfused ischemic tissue. In addition, we have attempted to introduce the reader to the relatively new concept of "site-specific" formation of radicals and how the use of "push-pull" techniques, such as chelation by high-affinity chelators or displacement by non-redox-active metals such as zinc, may decrease postischemic reperfusion injury. Finally, we have identified a class of compounds that affect the oxidation state of redox-active metals, and have demonstrated how these compounds may also represent a new therapeutic modality. In conclusion, both academic and nonacademic surgeons should have profited from reading this article. For the academic surgeon, who may do research, several new cytoprotectants requiring further study in both in vitro and in vivo models have been identified. For the nonacademic surgeon in clinical practice the realization that there are several promising areas of research that may yield new therapies to mitigate postischemic reperfusion injury should have been gained.

Reliability and accuracy of resident evaluations of surgical faculty.

This study examines the reliability and accuracy of ratings by general surgery residents of surgical faculty. Twenty-three of 33 residents anonymously and voluntarily evaluated 62 surgeons in June, 1988; 24 of 28 residents evaluated 64 surgeons in June, 1989. Each resident rated each surgeon on a 5-point scale for each of 10 areas of performance: technical ability, basic science knowledge, clinical knowledge, judgment, peer relations, patient relations, reliability, industry, personal appearance, and reaction to pressure. Reliability analyses evaluated internal consistency and interrater correlation. Accuracy analyses evaluated halo error, leniency/severity, central tendency, and range restriction. Ratings had high internal consistency (coefficient alpha = 0.97). Interrater correlations were moderately high (average Pearson correlation = 0.63 among raters). Ratings were generally accurate, with halo error most prevalent and some evidence of leniency. Ratings by chief residents had the least halo. Results were generally replicable across the two academic years. We conclude that anonymous ratings of surgical faculty by groups of residents can provide a reliable and accurate evaluation method, ratings by chief residents are most accurate, and halo error may pose the greatest threat to accuracy, pointing to the need for greater definition of evaluation items and scale points.

Postoperative peritoneal blood salvage with autotransfusion after hepatic trauma.

Postoperative peritoneal blood salvage with autotransfusion is technically feasible and may serve as an adjunctive measure in the management of severely injured patients with hepatic trauma and nonmechanical hemorrhage. Its effectiveness and ultimate place in the care of patients with trauma will be determined only after continued study.

Resident evaluation of surgical faculty.

This study examines the association between resident evaluations of surgical faculty and measures of teaching activity and practice characteristics. Twenty-three of 33 general surgery residents, anonymously and voluntarily rated 62 faculty surgeons in 10 areas of performance. This was repeated 1 year later with 24 of 28 residents and 64 surgeons. Ratings were reliable (test-retest on overall mean rating, r = 0.91, P less than 0.01). Factor analysis of ratings by residents in postgraduate year (PGY) 5 extracted a judgment factor and an interpersonal skills factor. Ratings by other PGYs were unidimensional. Faculty subgroups that performed more than two major procedures per week at the hospital (P less than 0.01) attended the weekly Mortality and Morbidity conference more than once per month (P less than 0.05) and/or published one or more research reports (P less than 0.05) received higher ratings than those who did not. Among general surgeons (n = 35), ratings of interpersonal skill by PGY 5 residents correlated inversely with complication rate (r = -0.41, P less than 0.05) and overall ratings by PGYs 3 and 4 correlated inversely with mean patient length-of-stay (LOS; r = -0.44, P less than 0.05). These remained significant after statistical adjustment for case mix differences and differences in the amount of contact with residents. Resident ratings were unrelated to mean patient age, the mean number of diagnoses per patient, and the mean number of procedures per patient.(ABSTRACT TRUNCATED AT 250 WORDS)