Relation of surgical volume to outcome in eight common operations: results from the VA National Surgical Quality Improvement Program.

OBJECTIVE: To examine, in the Veterans Health Administration (VHA), the relation between surgical volume and outcome in eight commonly performed operations of intermediate complexity. SUMMARY BACKGROUND DATA: In multihospital health care systems such as VHA, consideration is often given to closing low-volume surgical services, with the assumption that better surgical outcomes are achieved in hospitals with larger surgical volumes. Literature data to support this assumption in intermediate-complexity operations are either limited or controversial. METHODS: The VHA National Surgical Quality Improvement Program data on nonruptured abdominal aortic aneurysmectomy, vascular infrainguinal reconstruction, carotid endarterectomy (CEA), lung lobectomy/pneumonectomy, open and laparoscopic cholecystectomy, partial colectomy, and total hip arthroplasty were used. Pearson correlation, analysis of variance, mixed effects hierarchical logistic regression, and automatic interaction detection analysis were used to assess the association of annual procedure/specialty volume with risk-adjusted 30-day death (and stroke in CEA). RESULTS: Eight major surgical procedures (68,631 operations) were analyzed. No statistically significant associations between procedure or specialty volume and 30-day mortality rate (or 30-day stroke rate in CEA) were found. CONCLUSIONS: In VHA hospitals, the procedure and surgical specialty volume in eight prevalent operations of intermediate complexity are not associated with risk-adjusted 30-day mortality rate from these operations, or with the risk-adjusted 30-day stroke rate from CEA. Volume of surgery in these operations should not be used as a surrogate for quality of surgical care.

The Department of Veterans Affairs' NSQIP: the first national, validated, outcome-based, risk-adjusted, and peer-controlled program for the measurement and enhancement of the quality of surgical care. National VA Surgical Quality Improvement Program.

OBJECTIVE: To provide reliable risk-adjusted morbidity and mortality rates after major surgery to the 123 Veterans Affairs Medical Centers (VAMCs) performing major surgery, and to use risk-adjusted outcomes in the monitoring and improvement of the quality of surgical care to all veterans. SUMMARY BACKGROUND DATA: Outcome-based comparative measures of the quality of surgical care among surgical services and surgical subspecialties have been elusive. METHODS: This study included prospective assessment of presurgical risk factors, process of care during surgery, and outcomes 30 days after surgery on veterans undergoing major surgery in 123 medical centers; development of multivariable risk-adjustment models; identification of high and low outlier facilities by observed-to-expected outcome ratios; and generation of annual reports of comparative outcomes to all surgical services in the Veterans Health Administration (VHA). RESULTS: The National VA Surgical Quality Improvement Program (NSQIP) data base includes 417,944 major surgical procedures performed between October 1, 1991, and September 30, 1997. In FY97, 11 VAMCs were low outliers for risk-adjusted observed-to-expected mortality ratios; 13 VAMCs were high outliers for risk-adjusted observed-to-expected mortality ratios. Identification of high and low outliers by unadjusted mortality rates would have ascribed an outlier status incorrectly to 25 of 39 hospitals, an error rate of 64%. Since 1994, the 30-day mortality and morbidity rates for major surgery have fallen 9% and 30%, respectively. CONCLUSIONS: Reliable, valid information on patient presurgical risk factors, process of care during surgery, and 30-day morbidity and mortality rates is available for all major surgical procedures in the 123 VAMCs performing surgery in the VHA. With this information, the VHA has established the first prospective outcome-based program for comparative assessment and enhancement of the quality of surgical care among multiple institutions for several surgical subspecialties. Key features to the success of the NSQIP are the support of the surgeons who practice in the VHA, consistent clinical definitions and data collection by dedicated nurses, a uniform nationwide informatics system, and the support of VHA administration and managerial staff.

Risk adjustment of the postoperative mortality rate for the comparative assessment of the quality of surgical care: results of the National Veterans Affairs Surgical Risk Study.

BACKGROUND: The National Veterans Affairs Surgical Risk Study was designed to collect reliable, valid data on patient risk and outcomes for major surgery in the Veterans Health Administration and to report comparative risk-adjusted postoperative mortality rates for surgical services in Veterans Health Administration. STUDY DESIGN: This cohort study was conducted in 44 Veterans Affairs Medical Centers. Included were 87,078 major noncardiac operations performed under general, spinal, or epidural anesthesia between October 1, 1991, and December 31, 1993. The main outcomes measure was all-cause mortality within 30 days after the index procedure. Multivariable logistic regression risk-adjustment models for all operations and for eight surgical subspecialties were developed. Risk-adjusted surgical mortality rates were expressed as observed-to-expected ratios and were compared with unadjusted 30-day postoperative mortality rates. RESULTS: Patient risk factors predictive of postoperative mortality included serum albumin level, American Society of Anesthesia class, emergency operation, and 31 additional preoperative variables. Considerable variability in unadjusted mortality rates for all operations was observed across the 44 hospitals (1.2-5.4%). After risk adjustment, observed-to-expected ratios ranged from 0.49 to 1.53. Rank order correlation of the hospitals by unadjusted and risk-adjusted mortality rates for all operations was 0.64. Ninety-three percent of the hospitals changed rank after risk adjustment, 50% by more than 5 and 25% by more than 10. CONCLUSIONS: The Department of Veterans Affairs has successfully implemented a system for the prospective collection and comparative reporting of risk-adjusted postoperative mortality rates after major noncardiac operations. Risk adjustment had an appreciable impact on the rank ordering of the hospitals and provided a means for monitoring and potentially improving the quality of surgical care.

Risk adjustment of the postoperative morbidity rate for the comparative assessment of the quality of surgical care: results of the National Veterans Affairs Surgical Risk Study.

BACKGROUND: The National Veterans Affairs Surgical Risk Study was designed to collect reliable, valid data on patient risk and outcomes for major surgery in the Veterans Health Administration and to report comparative risk-adjusted postoperative mortality and morbidity rates for surgical services in the Veterans Health Administration. STUDY DESIGN: This was a cohort study conducted at 44 Veterans Affairs Medical Centers closely affiliated with university medical centers. Included were 87,078 major noncardiac operations performed under general, spinal, or epidural anesthesia between October 1, 1991, and December 31, 1993. The main outcomes measures in this report are 21 postoperative adverse events (morbidities) occurring within 30 days after the index procedure. Multivariable logistic regression risk-adjustment models for all operations and for eight surgical subspecialties were developed. RESULTS: Patient risk factors predictive of postoperative morbidity included serum albumin level, American Society of Anesthesia class, the complexity of the operation, and 17 other preoperative risk variables. Wide variation in the unadjusted rates of one or more postoperative morbidities for all operations was observed across the 44 hospitals (7.4-28.4%). Risk-adjusted observed-to-expected ratios ranged from 0.49 to 1.46. The Spearman rank order correlation between the ranking of the hospitals based on unadjusted morbidity rates and risk-adjusted observed-to-expected ratios for all operations was 0.87. There was little or no correlation between the rank order of the hospitals by risk-adjusted morbidity and risk-adjusted mortality. CONCLUSIONS: The Department of Veterans Affairs has successfully implemented a system for the prospective collection and comparative reporting of postoperative mortality and morbidity rates after major noncardiac operations. Risk adjustment had only a modest effect on the rank order of the hospitals.

The National Veterans Administration Surgical Risk Study: risk adjustment for the comparative assessment of the quality of surgical care.

BACKGROUND: The use of surgical outcome in the comparative assessment of the quality of surgical care is predicted on the development of proper models that adjust for the severity of the preoperative risk factors of the patient. The National Veterans Administration Surgical Risk Study was designed to collect reliable, valid data about patient risk and outcome for major surgery in the Veterans Health Administration (VHA) and to report comparative risk-adjusted surgical morbidity and mortality rates for surgical services in VHA. This study describes the rationale and methods used in the Risk Study and reports on the frequency distribution of the data elements that will be used in the development of risk-adjusted reporting of surgical outcome. STUDY DESIGN: This study was a prospective observational study in which dedicated nurses collected preoperative, intraoperative, and outcome data on patients undergoing noncardiac operations using general, spinal, and epidural anesthesia in 44 Veterans Administration Medical Centers. Outcome measures included all cause mortality within the 30 days after the index procedure and 21 major morbidities. RESULTS: Eighty-three thousand nine hundred fifty-eight cases meeting inclusion criteria were entered in the study between October 1, 1991 and December 31, 1993. Ninety-seven percent of patients were men, with a mean age of 60.1 +/- 13.6 (standard deviation) years. The most common preoperative risk factors were smoking (40.7 percent) and hypertension (36.1 percent). Of the patients, 84.6 percent had one or more risk factors. The most common procedures were transurethral resection of the prostate gland (6.7 percent), total knee replacement (3.1 percent), thromboendarterectomy (2.4 percent), partial colectomy (2.2 percent), and total hip replacement (2 percent). The unadjusted mortality rate was 3.1 percent at 30 days. The most common postoperative morbidities were pneumonia (3.6 percent), urinary tract infection (3.5 percent), and failure to wean from the ventilator at 48 hours postoperatively (3.2 percent). Seventeen percent of the patients have one or more major complications. CONCLUSIONS: The Veterans Health Administration has successfully implemented an outcome reporting system for major surgery that prospectively collects patient risk and outcome information reliably and validly. Risk adjustment models and comparative hospital-specific rates of risk-adjusted outcomes are currently being developed.

Comparison of postoperative mortality and morbidity in VA and nonfederal hospitals.

We compared postoperative mortality and morbidity rates in the Veterans Health Administration (VA) to those in nonfederal hospitals, using multivariate analysis to adjust for the patient characteristics of age, diagnosis, comorbidity, and severity of illness. We used a total of 544,000 patient discharge records (330,000 nonfederal and 214,000 VA) from 1987 through 1988 and compared 118 surgical procedures or procedure groups composed of 314 individual surgical procedures. We found no significant differences in postoperative mortality rates between the VA and nonfederal hospital systems for 110 of 118 surgical procedures or procedure groups. Endarterectomy, cervical esophagostomy, and esophageal anastomosis or esophagocolostomy showed significantly lower postoperative mortality in the VA hospitals compared to nonfederal hospitals (P = 0.05). VA postoperative mortality rates that were higher than those in nonfederal hospitals and could not be entirely explained by adjusting for patient characteristics were found for suture of ulcer, cholecystostomy, colon surgery, small intestine surgery, and reopening of recent thoracotomy site (P = 0.05). Respiratory, gastrointestinal, and urinary postoperative morbidity were generally lower in the VA hospitals than in nonfederal hospitals (P = 0.05). Infections were generally higher in the VA hospitals than in nonfederal hospitals. Pulmonary embolism, deep venous thrombosis, shock due to surgery or anesthesia, mediastinitis, hemorrhage, cardiac, and central nervous system morbidity showed no significant differences. These data demonstrate that VA postoperative mortality and morbidity in 118 surgical procedures or procedure groups is comparable to those in nonfederal hospitals.

Comparison of postoperative mortality in VA and private hospitals.

OBJECTIVE: This study compared unselected VA (Department of Veterans Affairs) and private multi-hospital postoperative mortality rates. In the absence of national standards for postoperative mortality rates and in view of the unique volume and range of surgical procedures studied, the second objective is to help establish national standards through the dissemination of these postoperative mortality norms. SUMMARY BACKGROUND DATA: Public Law 99-166, Section 204, enacted by Congress December 3, 1985, required that the VA compare postoperative mortality and morbidity rates for each type of surgical procedure it performs with the prevailing national standard and analyze any deviation between such rates in terms of patient characteristics. METHODS: The authors compared postoperative mortality in the VA to that in private hospitals, adjusting for the patient characteristics of age, diagnosis, comorbidity, or severity of illness. We used a total of 830,000 patients discharge records (323,000 VA and 507,000 private patients) from 1984 through 1986 among 309 individual surgical procedures within 113 comparison surgical procedures or procedure groups. RESULTS: The authors found no significant differences in postoperative mortality rates between the VA and private hospital systems for 105 of the 113 surgical procedures or procedure groups. VA postoperative mortality rates that were higher than those in private hospitals were found for suture of ulcer, revision of gastric anastomosis, small-to-small intestinal anastomosis, appendectomy, and reclosure of postoperative disruption of abdominal wall (p = 0.05). Vascular bypass surgery, portal systemic venous shunt, and esophageal surgery showed a significantly lower postoperative mortality in the VA as compared with that in private hospitals (p = 0.05). CONCLUSIONS: VA postoperative mortality in 113 surgical procedures or procedure groups is comparable to that in private hospitals.

Changes in serum CPK, LDH, and their isoenzymes in the perioperative period in patients undergoing craniotomy.

The perioperative changes in the serum concentration of creatine phosphokinase (CPK) and its isoenzymes MM, MB, and BB and of lactic dehydrogenase (LDH) and its isoenzymes LDH1 to LDH5 were determined during craniotomy in order to distinguish operation-induced changes in these enzymes from those due to acute myocardial infarction and malignant hyperthermia. Twenty-eight male patients, 29 to 76 years of age (mean +/- SD = 58 +/- 13.2 years), undergoing craniotomy for tumor reseaction (n = 26) or cerebral artery aneurysm clipping (n = 2) were included in this study. Ten serial blood samples were obtained from each patient: one sample before and another after induction of anesthesia, and eight samples after the incision, over a period of 70 h. The preinduction serum CPK level of 97 +/- 32 U/L (mean +/- SD) increased gradually and significantly and reached the peak level of 542 +/- 116 U/L 34 h after incision (p <0.05). Whereas all of the CPK isoenzymes increased in terms of U/L after incision, only the MM fraction (expressed as percent of total CPK) increased, and the MB and BB fractions (expressed as percent of total CPK) decreased. The preinduction serum LDH level of 150 +/- 42 U/L (mean +/- SD) increased gradually after incision and reached the peak level of 210 +/- 32 U/L 58 h after incision (p <0.05). LDH2 as a percent of total LDH decreased significantly, but the LDH1/LDH2 ratio did not change. LDH4 and LDH5, as percents of total LDH, increased significantly. The large increases in total serum CPK and the concomitant decrease in MB percent after craniotomy may minimize and/or mask the percentage increase in the MB level following acute myocardial infarction. The perioperative serum CPK level as a marker in the diagnosis of malignant hyperthermia should be interpreted in light of the present results and in conjunction with clinical symptomatology.

Serum creatine phosphokinase, lactic dehydrogenase, and their isoenzymes in the perioperative period.

The purpose of the present investigation was to determine the normal perioperative variations in the serum concentration of creatine phosphokinase (CPK) and its isoenzymes MM, MB, and BB, and of lactic dehydrogenase (LDH) and its isoenzymes LDH1 to LDH5 to distinguish operation-induced changes in these enzymes from those due to acute myocardial infarction or malignant hyperthermia. In 30 patients, 52 to 75 years of age undergoing elective orthopedic operations, 10 serial blood samples were obtained in the perioperative period: two samples before skin incision and eight samples after the incision over a time span of 70 hours. The preinduction mean serum CPK level of 141 U/L increased gradually and significantly and reached a maximum mean concentration of 809 U/L 34 hours after incision (p less than 0.01). The CPK-MM percent increased after incision, whereas that of CPK-MB and CPK-BB decreased, although their absolute values in terms of U/L rose. The preinduction mean serum LDH value of 173 U/L increased gradually after incision and achieved peak levels at 34 hours (203 U/L) and 58 hours (210 U/L) after incision (p less than 0.05). The LDH1:LDH2 ratio did not change. The LDH5 percent increased and peaked 10 hours after incision (p less than 0.05). There was a significant correlation between severity of operation-induced tissue damage and the serum CPK concentration (p less than 0.001). The large increase in total CPK (primarily MM fraction) occurring after surgery may minimize the percentile effects caused by an increase in MB level due to myocardial infarction.

Yersinia enterocolitica infection complicated by intestinal perforation.

Yersinia enterocolitica causes primarily ileocolitis in human beings, and is manifested by abdominal pain, diarrhea, and fever. Usually, it is a self-limiting disease. Local or systemic complications are rare. A 71-year-old man with Y enterocolitica colitis complicated by perforation and abscess formation is described. This complication is very rare, and the four other cases that have been reported in the literature are reviewed.

The need for careful operative dissection in Moosman's area during cholecystectomy.

Anatomy contributes two operative difficulties to the surgeon during cholecystectomy; one is access or exposure, and second is variation. Eighty-five per cent of all variations in the hepatic pedicle are found within Moosman's area which is an area the size of a fifty cent coin in the cystohepatic duct angle. Fifty per cent of the variation within Moosman's area is a potential hazard during cholecystectomy. Vessels passing ventrally are most important because bile ducts may be injured in efforts to stop hemorrhage from these vessels. Moosman's (25) area is indeed the zone of careful operative procedure in cholecystectomy.

Emergency operation for upper gastrointestinal hemorrhage.

From January 1973 through December 1977, 580 patients presented with 624 episodes of upper gastrointestinal hemorrhage at the University fo Pittsburgh Health Center Hospitals. Ninety-one patients (15%) underwent operation for uncontrollable hemorrhage. Operative mortality was 30 per cent for all patients and 21 per cent for patients with gastroduodenal bleeding (duodenal ulcer, gastric ulcer, erosive gastritis). In patients with gastroduodenal bleeding, seven of 15(47%) with preoperative hypotensive shock (systolic b.p. less than or equal to .02). Twenty-five patients had vagotomy and pyloroplasty with suture ligation of bleeding ulcers, while 34 patients underwent gastric resection. The operative mortality for resection was 21 per cent (7/34) compared with 16 percent (4/25) for vagotomy and pyloroplasty. The incidence of rebleeding was 15 per cent (5/34) for resection and 8 per cent (2/25 for vagotomy and pyloroplasty. Nine patients (26%) has suture-line leaks following resection, and none were found after vagotomy and pyloroplasty. Severe of nine patients (78%) who had leaks after resection had hypotensive shock prior to operation. Six of the seven patients who died following gastric resection had complication (either leak or rebleeding) directly related to the operative procedure, while the four deaths following vagotomy and pyloroplasty occurred in patients not having procedure-related complications. Procedure-related morbidity (leaks and rebleeding) with resection (41%) was significantly higher than with vagotomy and pyloroplasty (8%) (P less than or equal to .01). These data show vagotomy and pyloroplasty to be the safer operation for patients with uncontrollable gastroduodenal hemorrhage, particularly those with preoperative hypotension.

Effect of ATP-MgCl2-glucose administration during hemorrhagic shock on cardiovascular function, metabolism, and survival.

Both exogenous glucose and adenosine triphosphate--magnesium chloride (ATP-MgCl2, used separately, have been reported to prolong survival after hemorrhagic shock. The purpose of this study was to determine whether intravenously administered glucose plus ATP-MgCl2 given together during hemorrhagic shock would improve cardiac function and survival. Further, we investigated whether glucose had any real additive effect when used in conjunction with ATP-MgCl2, by using ATP-MgCl2 alone and with equimolar mannitol. Awake pigs were bled 40% of total blood volume within 10 minutes. Five pigs received no treatment; 4 received lactated Ringer's equivalent to the initial bled volume; 5 received ATP (206 microM/kg), MgCl2 (206 microM/kg) and glucose (0.5 g/kg); 5 received ATP-MgCl2, glucose and lactated Ringer's; 5 received ATP-MgCl2 alone, and 6 received ATP-MgCl2 and mannitol (0.5 g/kg). All treated groups received sodium bicarbonate (2 mEq/kg). Duration of this experiment was 240 minutes. Mean survival of those which received no treatment was 36.8 +/- SE 2.9 minutes; those which received ATP-MgCl2-glucose had a significantly longer survival with a mean of 157.6 +/- 12.0 minutes (p less than 0.05). With Ringers' alone, the mean survival was 92.6 +/- 0.7 minutes and those which received ATP-MgCl2-glucose plus Ringer's had a significantly greater mean survival of 159-0 +/- 2.7 minutes (p less than 0.05). Mean survival of those which received ATP-MgCl2-mannitol was statistically significantly greater at 200.8 +/- 10.3 minutes than ATP-MgCl2-glucose alone with Ringer's (p less than 0.01). Mean survival was greatest in those which received ATP-MgCl2 alone at 201.2 +/- 9.5 minutes (p less than 0.01), and statistically significantly greater than any other treatment group except ATP-MgCl2-mannitol. ATP-MgCl2 alone significantly increased survival compared to those which received ATP-MgCl2-glucose.

Lower esophageal sphincter pressure during the normal menstrual cycle.

Lower esophageal sphincter pressure (LESP), basal gastric pH, and plasma levels of gastrin, estradiol, and progesterone were determined in ten women known to have normal menstrual cycles. All determinations were performed both during the follicular phase (Days 2 to 8) and during the luteal phase (Days 20 to 30). In addition, an intraluminal pH probe placed 5 cm. above the lower esophageal sphincter was used to test for the presence of acid reflux in response to three provocative procedures. LESP during the follicular phase was 19.0 +/- 1.5 mm. Hg (mean +/- S.E.M.) and during the luteal phase 16.5 +/- 1.3 mm. Hg (p less than 0.01). Basal gastric pH and plasma gastrin levels were similar at both times. Plasma estradiol in the follicular phase (76.1 +/- 7.0 pg. per milliliter) increased twofold during the luteal phase (159.0 +/- 6.0) (p less than 0.01). Plasma progesterone increased from a level of 1.5 +/- 0.8 ng. per milliliter during the follicular phase to 19.2 +/- 4.2 during the luteal phase. Coincident with these changes in LESP and increases in steroid levels, acid reflux was detected in five women during the luteal phase but was present in only one during the follicular phase.

The pony as a model for septic shock.

This study was conducted to determine the feasibility of using alert, conscious ponies as a model for septic shock in man. Ten ponies were given 0.7-5 X 10(9) organisms/kg of body weight of live E coli intravenously over one hour. All ponies died and exhibited signs of low cardiac output septic shock. significant decreases were found in cardiac index to 3.15 +/- 0.1 liters/min/m2 (P less than 0.05), white blood cell count to 1,930 +/- 100 cells/m3 (P less than 0.05), preterminal blood glucose to 75 +/- 5 mg/dl (P less than 0.05), PaO2 to 75.7 +/- 5.7 mm Hg (P less than 0.05), and pH to 7.15 +/- 0.5 (P less than 0.05). Increases were noted in systemic resistance to 3,869 +/- 322 dynes/dic/cm-5 (P less than 0.05), pulmonary resistance to 770.8 +/- 11.12 dynes/sec/cm-5 (P less than 0.05), pulmonary arterial pressure to 41 +/- 7 mm Hg (P less than 0.05), pulmonary wedge pressure to 19.5 +/- 2.5 mm Hg (P less than 0.05), intrapulmonary shunt to 16.43 +/- l.73% (P less than 0.05), early blood glucose to 204 +/- 9.0 mg/dl (P less than 0.05), and excess lactate concentration to 53.06 +/- 5.3 mg/dl (P less than 0.05). From these data it appears that the septic pony shows changes similar to low output septic shock documented in man.