Assessment of mortality rates for congenital heart defects and surgeons' performance

Prevalence of congenital heart disease among school children in Qinghai Province

Objectives

This study aimed to investigate the prevalence of congenital heart disease (CHD) among school children in Qinghai province, a high-altitude region in China.

Methods

A cross-sectional study was conducted among school-aged children in 2019. All subjects completed a survey with a structure questionnaire and underwent CHD screening. CHD was screened by standard physical examination and further confirmed by echocardiography. Multivariate logistic regression were used to estimate the association of CHD prevalence with gender, nationality, and altitude.

Results

A total of 43,562 children aged 3–19 years participated in the study. The mean (SD) age was 11.2 (3.3) years. 49.7% were boys, and 80.0% were of Tibetan. CHD was identified in 293 children, with an overall prevalence of 6.73 ‰. Among them, 239 were unrecognized CHD, yielding a prevalence of 5.49 ‰. Atrial septal defect accounted for 51.9% of the CHD, followed by patent ductus arteriosus (31.1%), ventricular septal defect (9.9%). The CHD prevalence was significantly higher in female (8 ‰), Han race (18 ‰), children lived in Qumalai county (13 ‰), and children lived in a higher altitude (13 ‰). Female had greater prevalence of total CHD, atrial septal defect, and patent ductus arteriosus, but insignificant difference was observed in ventricular septal defect prvalence than male. In multivariable logistic regression analyses, female (OR, 1.48; 95% CI, 1.17–1.87, P = 0.001), Han population (OR, 3.28; 95% CI, 1.67–6.42, P = 0.001), and higher altitudes (OR, 2.28; 95% CI, 1.74–3.00, P < 0.001) were shown to be independently association with CHD prevalence.

Conclusions

The prevalence of CHD in Qinghai province was 6.73 ‰. Altitude elevation, female, and Han population were independently association with CHD prevalence.

Computed tomography and magnetic resonance imaging in neonates with congenital cardiovascular disease

Most cardiac diseases in the newborn are caused by structural abnormalities developed in utero. With few exceptions, palliative and definitive treatments require cardiac surgery. The diagnosis and management decisions regarding uncomplicated lesions, such as atrial septal defect, ventricular septal defect, patent ductus arteriosus, and tetralogy of Fallot, can be accomplished by echocardiography alone. Abnormalities beyond the sonographic window, complex 3-dimensional lesions, and detailed functional information require additional imaging. In the past, this was fulfilled by catheter angiography, but today much of the information can be obtained from noninvasive computed tomography angiography and magnetic resonance imaging. This article discusses the design and application of these imaging techniques to the newborn, with emphasis on safety, efficacy, and image quality. Understanding the capabilities and limitations of these techniques is crucial for making rational choices among imaging options based on sound risk and benefit considerations. Important examples of congenital heart lesions have been illustrated with 3-dimensional reconstruction from computed tomography and magnetic resonance images.

EM for regularized zero-inflated regression models with applications to postoperative morbidity after cardiac surgery in children

This paper proposes a new statistical approach for predicting postoperative morbidity such as intensive care unit length of stay and number of complications after cardiac surgery in children. In a recent multi-center study sponsored by the National Institutes of Health, 311 children undergoing cardiac surgery were enrolled. Morbidity data are count data in which the observations take only nonnegative integer values. Often, the number of zeros in the sample cannot be accommodated properly by a simple model, thus requiring a more complex model such as the zero-inflated Poisson regression model. We are interested in identifying important risk factors for postoperative morbidity among many candidate predictors. There is only limited methodological work on variable selection for the zero-inflated regression models. In this paper, we consider regularized zero-inflated Poisson models through penalized likelihood function and develop a new expectation-maximization algorithm for numerical optimization. Simulation studies show that the proposed method has better performance than some competing methods. Using the proposed methods, we analyzed the postoperative morbidity, which improved the model fitting and identified important clinical and biomarker risk factors.

Surgical volume-to-outcome relationship and monitoring of technical performance in pediatric cardiac surgery

A significant inverse relationship of surgical institutional and surgeon volumes to outcome has been demonstrated in many high-stakes surgical specialties. By and large, the same results were found in pediatric cardiac surgery, for which a more thorough analysis has shown that this relationship depends on case complexity and type of surgical procedures. Lower-volume programs tend to underperform larger-volume programs as case complexity increases. High-volume pediatric cardiac surgeons also tend to have better results than low-volume surgeons, especially at the more complex end of the surgery spectrum (e.g., the Norwood procedure). Nevertheless, this trend for lower mortality rates at larger centers is not universal. All larger programs do not perform better than all smaller programs. Moreover, surgical volume seems to account for only a small proportion of the overall between-center variation in outcome. Intraoperative technical performance is one of the most important parts, if not the most important part, of the therapeutic process and a critical component of postoperative outcome. Thus, the use of center-specific, risk-adjusted outcome as a tool for quality assessment together with monitoring of technical performance using a specific score may be more reliable than relying on volume alone. However, the relationship between surgical volume and outcome in pediatric cardiac surgery is strong enough that it ought to support adapted and well-balanced health care strategies that take advantage of the positive influence that higher center and surgeon volumes have on outcome.

Surgical volume and center effects on early mortality after pediatric cardiac surgery: 25-year North American experience from a multi-institutional registry

Mortality after pediatric cardiac surgery varies among centers. Previous research suggests that surgical volume is an important predictor of this variation. This report characterizes the relative contribution of patient factors, center surgical volume, and a volume-independent center effect on early postoperative mortality in a retrospective cohort study of North American centers in the Pediatric Cardiac Care Consortium (up to 500 cases/center/year). From 1982 to 2007, 49 centers reported 109,475 operations, 85,023 of which were analyzed using hierarchical multivariate logistic regression analysis. Patient characteristics varied significantly among the centers. The adjusted odds ratio (OR) for mortality decreased more than 10-fold during the study period (1982 vs. 2007: OR, 12.27, 95 % confidence interval [CI], 8.52-17.66; p < 0.0001). Surgical volume was associated inversely with odds of death (additional 100 cases/year: OR, 0.84; 95 % CI, 0.78-0.90; p < 0.0001). In the analysis of interactions, this effect was fairly consistent across age groups, risk categories (except the lowest), and time periods. However, a volume-independent center effect contributed substantially more to the risk model than did the volume. The Risk Adjusted Classification for Congenital Heart Surgery, version 1 (RACHS-1) risk category remains the strongest predictor of postoperative mortality through the 25-year study period. In conclusion, center-specific variation exists but is only partially explained by operative volume. Low-risk operations are safely performed at centers in all volume categories, whereas regionalization or other quality improvement strategies appear to be warranted for moderate- and high-risk operations. Potentially preventable mortality occurs at centers in all volume categories studied, so referral or regionalization strategies must target centers by observed outcomes rather than assume that volume predicts quality.

Technical performance scores in congenital cardiac operations: a quality assessment initiative

BACKGROUND

Technical performance in congenital cardiac operations and its association with clinical outcomes was previously examined in infants and neonates. The purpose of this study was the development and implementation of a system for measuring technical performance in the majority of congenital cardiac operations to be used as a surgeon's self-assessment tool.

METHODS

Using the methodologic framework piloted at our institution, measures of technical performance were created for more than 90% of all congenital cardiac operations. Each operation was divided into multiple subprocedures to be assessed separately. Criteria for technical scores were created using a consensus panel of senior clinicians and were based primarily on the predischarge echocardiographic findings and need for early postoperative reinterventions. This system of procedure modules was then piloted by prospectively assigning technical scores to all patients undergoing operations.

RESULTS

Thirty modules were created covering more than 90% of the cardiac operations performed. One hundred eighty-five patients were enlisted. One hundred one (54.6%) cases were scored as class 1 (highest), 46 (24.9%) cases as class 2, 22 (11.9%) cases as class 3 (lowest); 16 cases (8.6%) could not be scored. The results were further analyzed by RACHS (Risk Adjustment for Congenital Heart Surgery) categories and outcomes. Valve-procedure-specific criteria were calibrated to reflect specific echocardiographic measurements.

CONCLUSIONS

The development and implementation of a broad technical performance self-assessment system for congenital cardiac operations is possible. Based on this scoring system, the impact of a less than optimal (2 or 3) technical score depends on case risk category, with higher mortality in the higher risk group, and increased resource use for lower risk procedures.

Variation in outcomes for benchmark operations: an analysis of the Society of Thoracic Surgeons Congenital Heart Surgery Database

BACKGROUND

We evaluated outcomes for common operations in The Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHSDB) to provide contemporary benchmarks and examine variation between centers.

METHODS

Patients undergoing surgery from 2005 to 2009 were included. Centers with greater than 10% missing data were excluded. Discharge mortality and postoperative length of stay (PLOS) among patients discharged alive were calculated for 8 benchmark operations of varying complexity. Power for analyzing between-center variation in outcome was determined for each operation. Variation was evaluated using funnel plots and Bayesian hierarchical modeling.

RESULTS

Eighteen thousand three hundred seventy-five index operations at 74 centers were included in the analysis of 8 benchmark operations. Overall discharge mortality was: ventricular septal defect (VSD) repair = 0.6% (range, 0% to 5.1%), tetralogy of Fallot (TOF) repair = 1.1% (range, 0% to 16.7%), complete atrioventricular canal repair (AVC) = 2.2% (range, 0% to 20%), arterial switch operation (ASO) = 2.9% (range, 0% to 50%), ASO + VSD = 7.0% (range, 0% to 100%), Fontan operation = 1.3% (range, 0% to 9.1%), truncus arteriosus repair = 10.9% (0% to 100%), and Norwood procedure = 19.3% (range, 0% to 100%). Funnel plots revealed that the number of centers characterized as outliers were VSD = 0, TOF = 0, AVC = 1, ASO = 3, ASO + VSD = 1, Fontan operation = 0, truncus arteriosus repair = 4, and Norwood procedure = 11. Power calculations showed that statistically meaningful comparisons of mortality rates between centers could be made only for the Norwood procedure, for which the Bayesian-estimated range (95% probability interval) after risk-adjustment was 7.0% (3.7% to 10.3%) to 41.6% (30.6% to 57.2%). Between-center variation in PLOS was analyzed for all operations and was larger for more complex operations.

CONCLUSIONS

This analysis documents contemporary benchmarks for common pediatric cardiac surgical operations and the range of outcomes among centers. Variation was most prominent for the more complex operations. These data may aid in quality assessment and quality improvement initiatives.

Blood lactate levels differ significantly between surviving and nonsurviving patients within the same risk-adjusted Classification for Congenital Heart Surgery (RACHS-1) group after pediatric cardiac surgery

This study aimed to examine the association between lactate levels in the first hours after surgery for congenital heart defects and the results of Risk-Adjusted Classification for Congenital Heart Surgery (RACHS-1) scoring and to evaluate serial lactate levels over time to determine whether they can serve as a supplementary tool for postoperative assessment within the same RACHS-1 group of patients. A retrospective cohort study was performed using data retrieved from a clinical database of 255 children who had surgery for congenital heart defects between 1999 and 2001 at Sheba Medical Center. Lactate levels were measured postoperatively four times (mg/dL units). The last sample was taken at the end of the surgical procedure, and lactate levels were measured at admission to the pediatrics critical care unit, then 6 and 12 h after admission. The lactate level was measured via arterial blood gases. A total of 27 deaths occurred, yielding a mortality rate of 7.4% when Norwood operations were excluded and 10.16% when they were included. The mean initial postoperative lactate level was significantly lower for survivors (42.2 ± 32.0 mg/dL) than for nonsurvivors (85.4 ± 54.1 mg/dL) (p < 0.01). The serial mean lactate levels decreased progressively for all surviving patients (r (2) = 0.96) compared with nonsurvivors (r (2) = 0.02). The lactate levels correlated with the RACHS-1 subgroups at each time point (r (2) > 0.96 for all). The Pearson correlations between postoperative lactate levels (last lactate measurement taken in the operating room) and cardiopulmonary bypass (CPB) duration (r = 0.549), clamp duration (r = 0.586), and the inotropic score (r = 0.466) (p < 0.001 for all) were significantly positive. The correlations between the maximum lactate levels (during the first 12 postoperative hours) and CPB duration (r = 0.496), clamp duration (r = 0.509), and the inotropic score (r = 0.633) (p < 0.001 for all) were extremely positive. The early elevation of lactate levels in RACHS-1 subgroups 1 to 3 were highly correlated with poor prognosis and death (p < 0.03). In addition, the lactate levels differed significantly between survivors and nonsurvivors within the same RACHS-1 subgroup. The survivors in RACHS-1 subgroups 1 to 3 had lower mean lactate levels than the nonsurvivors in this group (P = 0.011), and this also held true for the survivors and nonsurvivors in RACHS-1 subgroups 4 to 6 (P = 0.026). Lactate levels differed significantly between survivors and nonsurvivors within the same RACHS-1 subgroup. This combination allows the targeting of appropriately intensive interventions and therapies toward the sickest patients.

The importance of nomenclature for congenital cardiac disease: implications for research and evaluation

BACKGROUND

Administrative databases are often used for congenital cardiac disease research and evaluation, with little validation of the accuracy of the diagnostic codes.

METHODS

Metropolitan Atlanta Congenital Defects Program surveillance records were reviewed and classified using a version of the International Pediatric and Congenital Cardiac Code. Using this clinical nomenclature as the referent, we report the sensitivity and false positive fraction (1 - positive predictive value) of the International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis codes for tetralogy of Fallot, transposition of the great arteries, and hypoplastic left heart syndrome.

RESULTS

We identified 4918 infants and foetuses with congenital cardiac disease from the surveillance records. Using only the International Classification of Diseases diagnosis codes, there were 280 records with tetralogy, 317 records with transposition, and 192 records with hypoplastic left heart syndrome. Based on the International Pediatric and Congenital Cardiac Code, 330 records were classified as tetralogy, 163 records as transposition, and 179 records as hypoplastic left heart syndrome. The sensitivity of International Classification of Diseases diagnosis codes was 83% for tetralogy, 100% for transposition, and 95% for hypoplastic left heart syndrome. The false positive fraction was 2% for tetralogy, 49% for transposition, and 11% for hypoplastic left heart syndrome.

CONCLUSIONS

Analyses based on International Classification of Diseases diagnosis codes may have substantial misclassification of congenital heart disease. Isolating the major defect is difficult, and certain codes do not differentiate between variants that are clinically and developmentally different.

Developing a NSQIP module to measure outcomes in children's surgical care: opportunity and challenge

Under the guidance of the American College of Surgeons (ACS) and in partnership with the US Department of Veterans Affairs (VA), the National Surgical Quality Improvement Program (NSQIP) has been developed to improve the quality of surgical care in adults on a national level. Its purpose is to provide reliable, risk-adjusted outcomes data so that surgical quality can be assessed and compared between institutions. Data analysis consists of reporting observed to expected ratios (O/E) for 30-day postoperative mortality and morbidity measurements. A surgical clinical nurse reviewer is assigned at each medical center to collect information on 97 variables, including preoperative, operative, and postoperative factors for patients undergoing major operations in the specialties of general and vascular surgery. Eligible operations are entered into the database on a structured 8-day cycle to ensure representative sampling of cases. Since the introduction of the program into the VA system, there has been a 47% reduction in 30-day postoperative mortality and a 42% reduction in 30-day postoperative morbidity. Over 160 institutions have enrolled with the ACS in its adult NSQIP. In 2005, a planning committee was formed by the ACS and the American Pediatric Surgical Association to explore the development of a children's surgery NSQIP module. In conjunction with the Colorado Health Outcomes Program at the University of Colorado, a program potentially applicable to all children's surgical specialties has been designed. This manuscript describes the development of that Children's ACS-NSQIP module.

Serial blood lactate levels as a predictor of mortality in children after cardiopulmonary bypass surgery

OBJECTIVE

To assess the role of serial lactate levels in determining outcome after cardiopulmonary bypass surgery in children.

DESIGN

Analysis of retrospectively collected data.

SETTING

Cardiac intensive care unit of a tertiary care children's hospital.

PATIENTS

Patients were 129 children who underwent surgery for congenital cardiac defects.

INTERVENTIONS

None.

MEASUREMENT AND MAIN RESULTS

Patients were categorized for disease severity using the Risk Adjustment for Congenital Heart Surgery method. Blood lactate levels were obtained at admission to the cardiac intensive care unit and then serially until they were <2 mmol/L. Lactime, time during which the lactate remains >2 mmol/L, was noted for each patient. The primary outcome measured was mortality. Secondary outcomes measured were ventilator days and hospital days. Six patients died, and of these five were neonates. Nonsurvivors had higher initial postoperative lactate concentration (p = .01), peak postoperative lactate concentration (p = .003), and lactime (p = .05). In binomial logistic regression analysis, lactime was the strongest predictor of mortality (p = .03). The positive predictive value for all age groups was highest for lactime >48 hrs, with a positive predictive value of 60%, and among the neonates it was 75%. Initial lactate level >6 mmol/L had a positive predictive value of only 6%, and the peak lactate level >6 mmol/L had a positive predictive value of only 15%. Lactime also had a significant association with ventilator days and hospital days among the survivors (p = .001).

CONCLUSIONS

Lactime was a useful predictor of mortality in children undergoing repair or palliation of congenital cardiac defects under cardiopulmonary bypass. Initial and peak lactate levels had a poor positive predictive value for mortality. Lactime also was associated with the number of ventilator days and hospital days in those who survived.

A population-based study relevant to seasonal variations in causes of death in children undergoing surgery for congenital cardiac malformations

AIMS

Our objectives were, first, to study seasonal distribution of perioperative deaths within 30 days after surgery, and late death, in children undergoing surgery for congenitally malformed hearts, and second, to study the causes of late death.

METHODS

We analysed a retrospective cohort of 1,753 children with congenital cardiac malformations born and undergoing surgery in the period from 1990 through 2002 with a special focus on the causes of late death. The data was obtained from the registry of congenital cardiac malformations at Rikshospitalet, Oslo, and the Norwegian Medical Birth Registry. The mean follow-up from birth was 8.1 years, with a range from zero to 15.2 years.

RESULTS

During the period of follow-up, 204 (11.6%) of the children died having undergone previous surgery. Of these 124 (7.1%) died in the perioperative period, and 80 (4.5%) were late deaths. There were 56 late deaths during the 6 coldest months, compared with 24 during the 6 warmest months (p < 0.01). There was no significant seasonal variation in perioperative deaths. Respiratory infection was the most common cause of late death, and occurred in 25 children, of whom 24 died during the 6 coldest months. Of the 8 sudden late deaths, 7 occurred during the 6 coldest months. There was no seasonal variation for the other causes of death.

CONCLUSIONS

In children undergoing surgery for congenital cardiac malformations in Norway, there is a seasonal variation in late death, with a higher proportion occurring in the coldest months. Death related to respiratory infections predominantly occurs in the winter season, and is the overall most common cause of late death.

Causes of death after congenital heart surgery

BACKGROUND

There has been little research about the causes of death after congenital heart surgery.

METHODS

To determine whether mode of death differs after congenital heart surgery, we evaluated the cause of death for 100 consecutive postoperative deaths at our institution. Mode of death was determined based on retrospective chart review including available autopsy reports. Low output states were categorized into ventricular failure; inadequate postoperative physiology (technically adequate surgery and ventricular function, but persistent low cardiac output); pulmonary hypertension; and atrioventricular valve regurgitation.

RESULTS

There was considerable anatomic diversity among patients who died; 46 patients had single-ventricle physiology. The vast majority of patients (n = 79) were in the intensive care unit before surgery. Surgical repairs were revised at initial operation in 22 cases; 7 patients died in the operating room. Seventy-three patients had technically adequate surgical procedures, 23 had residual anatomic defects, and 4 were indeterminate. Thirty patients underwent additional surgical and 9 catheter-based procedures, although some were classified as rescue procedures performed to address minor anatomic or physiologic abnormalities as a last hope to rescue the patient from impending demise. Of 100 deaths, most (n = 52) were due to low cardiac output: 24 inadequate postoperative physiology, 19 ventricular failure, 8 pulmonary hypertension, and 1 valvar regurgitation. Other significant causes of death included sudden cardiac arrest (n = 11), sepsis (n = 11), and procedural complications (n = 8).

CONCLUSIONS

More than half of the deaths were due to low cardiac output, but not exclusively ventricular failure.

Patient safety and human factors in pediatric cardiac surgery

The patient safety movement and human factors studies are becoming an increasingly important part of everyday clinical practice. Pediatric cardiac surgery is a high-risk field that is very much dependent on safe practices and continuous research into improvement of outcomes. This article reviews the main research frameworks, methods used, and current findings in the area of patient safety and human factors within pediatric cardiac surgery.

Measurement of technical performance in congenital heart surgery: a pilot study

BACKGROUND

Although adequacy of repair after congenital heart surgery is a crucial determinant of clinical outcome, there is no current method of assessment. We sought to develop a process to measure the adequacy of repair for a diverse group of congenital heart procedures.

METHODS

Selected surgical procedures, consisting of repair of ventricular septal defect (VSD), tetralogy of Fallot (TOF), complete common atrioventricular canal (CAVC), and arterial switch operation, were divided into component subprocedures, each of which was assessed separately. Three outcome categories of "optimal," "adequate," and "inadequate" were defined by consensus according to postprocedure echocardiographic assessment. Outcome categories for conduction disturbance were also created. All patients undergoing one of the four procedures in 2004 were identified, and each subprocedure was assessed. Other clinical data were obtained from medical records. Repairs were scored as "optimal" if all attempted subprocedures and conduction were optimal, and "inadequate" if any was inadequate.

RESULTS

A total of 138 procedures were included. VSD repair was done in 46 patients (33%), TOF repair in 33 (24%), arterial switch operation in 36 (26%), and CAVC repair in 23 (17%). Optimal technical score was found in 28 (20%), adequate in 106 (77%), and inadequate in 4 (3%) (2 VSD, 1 TOF, 1 CAVC). Median length of stay was 8 days, and no patients died.

CONCLUSIONS

Despite procedural diversity and complexity, technical adequacy of repair can be assessed for congenital heart surgery.

Risk Scoring in Perioperative and Surgical Intensive Care Patients: A Review

PURPOSE

Assessing the risk and predicting the outcome of surgery, trauma, and surgical intensive care is an important aspect of perioperative practice. There have been attempts to devise and validate many scoring systems to predict the prognosis of patients having a similar severity of illness. This article reviews some of the commonly used systems with respect to their development, strengths, and limitations.

SOURCES

Published literature describing risk assessment scores and physiologic scoring systems for preoperative assessment, trauma, and surgical intensive care patients.

PRINCIPAL FINDINGS

Risk scores used in preoperative evaluation assist the clinician in optimizing the patient before, during, and after surgery. Scoring systems applied in intensive care units are useful as guidelines rather than accurate predictors of prognosis for individual patient. Many models are used for audit purposes, and some are used as performance measures and quality indicators of a unit; however, both utilities are controversial because of poor adjustment of these systems to case-mixtures.

CONCLUSIONS

Risk assessment scores may assist in the perioperative risk evaluation with respect to organ systems. Prognostication of critically ill patients belonging to a category of illness may be done using physiological scoring systems taking into account the difference in the case-mix of the particular unit.

Handling over-dispersion of performance indicators

OBJECTIVES

A problem can arise when a performance indicator shows substantially more variability than would be expected by chance alone, since ignoring such "over-dispersion" could lead to a large number of institutions being inappropriately classified as "abnormal". A number of options for handling this phenomenon are investigated, ranging from improved risk stratification to fitting a statistical model that robustly estimates the degree of over-dispersion.

DESIGN

Retrospective analysis of publicly available data on survival following coronary artery bypass grafts, emergency readmission rates, and teenage pregnancies.

SETTING

NHS trusts in England.

RESULTS

Funnel plots clearly show the influence of the method chosen for dealing with over-dispersion on the "banding" a trust receives. Both multiplicative and additive approaches are feasible and give intuitively reasonable results, but the additive random effects formulation appears to have a stronger conceptual foundation.

CONCLUSION

A random effects model may offer a reasonable solution. This method has now been adopted by the UK Healthcare Commission in their derivation of star ratings.

Funnel plots for comparing institutional performance

'Funnel plots' are recommended as a graphical aid for institutional comparisons, in which an estimate of an underlying quantity is plotted against an interpretable measure of its precision. 'Control limits' form a funnel around the target outcome, in a close analogy to standard Shewhart control charts. Examples are given for comparing proportions and changes in rates, assessing association between outcome and volume of cases, and dealing with over-dispersion due to unmeasured risk factors. We conclude that funnel plots are flexible, attractively simple, and avoid spurious ranking of institutions into 'league tables'.

Systematic review of the quality of surgical mortality monitoring

BACKGROUND

Mortality is the most tightly defined and used adverse event for audit and performance monitoring in surgery. However, to identify cause and therefore scope for improvement, accurate and timely data are required. The aim of this study was to perform a systematic review of the quality of measurement, reporting and monitoring of mortality as an outcome after surgery.

METHODS

A systematic review of published literature was undertaken for the 7-year interval 1993-1999. Grey and unpublished literature was obtained through the Royal College of Surgeons of England, from UK national audits and routine national hospital data collections.

RESULTS

Eligible monitoring systems included six UK national surgical audits, and cardiac and vascular surgery monitoring systems from North America and the UK. The definitions of 'surgical death' varied in several respects and deaths after discharge from hospital were rarely ascertained unless there was routine linkage to national death registers. There were very few published studies on validation of the completeness and accuracy of the data collection.

CONCLUSION

A comprehensive data collection system is needed for improving clinical performance, with ownership, but not necessarily data collection, resting with the surgeons concerned. Recording of risk factors and deaths after discharge from hospital is essential, whatever data collection system is used.

Risk factors for long intensive care unit stay after cardiopulmonary bypass in children

OBJECTIVES

To determine whether children who experience longer intensive care unit (ICU) stays after open heart surgery may be identified at admission by clinical criteria. To identify factors associated with longer ICU stays that are potential targets for quality improvement.

SETTING

Tertiary pediatric cardiac surgical center.

DESIGN

A retrospective review was performed of pre-, intra-, and postoperative factors for children undergoing open heart surgery. All factors were evaluated for strength of association with length of ICU stay (LOS) using a negative binomial model. After multiple analysis, factors were deemed significant if associated with a LOS with p < .02.

PATIENTS

A total of 355 pediatric patients who had cardiac surgery with cardiopulmonary bypass in a 1-yr period from April 1999 until March 2000.

MEASUREMENTS AND MAIN RESULTS

Children who fell above the 95th percentile for LOS in our institution occupied 30% of bed days and had a three-fold greater mortality. Of all clinical factors considered, those significantly associated with LOS were as follows: preoperative--mechanical ventilation, neonatal status, medical problems, and transfer from abroad; intraoperative--higher operative complexity, increased cardiopulmonary bypass time or ischemic time, and circulatory arrest; and postoperative--delayed sternal closure, sepsis, renal failure, pulmonary hypertension, chylothorax, diaphragm paresis, and arrhythmia. A model combining all factors identified preoperative mechanical ventilation, neonatal status, major medical problems, operative complexity, cardiopulmonary bypass time, and a postoperative complication score as independently associated with LOS (p < .01).

CONCLUSIONS

At the time of ICU admission after open heart surgery, clinical criteria are evident that highlight a child's risk of longer ICU stay. These pre- and intraoperative factors relate to LOS independent of subsequent postoperative events. Those postoperative complications that are most strongly associated with increased LOS are identified and, therefore, made accessible to quality control.

Early identification of divergent performance in congenital cardiac surgery

OBJECTIVES

Heterogeneous caseload and poorly quantified risk stratification make it difficult to monitor outcomes in congenital cardiac surgery. Reliance on formal statistical hypothesis testing may lead to substantial delays before a pattern of poor outcome can be established. Here, we report alternative methods for alerting surgeons to potential problems at an earlier stage.

METHODS

Graphical methods developed for monitoring adult cardiac surgery have been adapted for use in congenital cardiac surgery. To illustrate their potential, we have retrospectively examined mortality data for a single surgeon involving 315 cases. Partial risk adjustment has been carried out according to patient's age and the open/closed categorization of the surgical procedure. Additional information has been derived by ranking procedures in order of their complexity and displaying the proportion of the surgeon's cases in each complexity stratum.

RESULTS

The display of a surgeon's mortality data adjusted for age and open/closed category provides an easily understood chart of performance and allows one to identify periods when performance appears divergent, relative to the surgeon's own overall standards. Cases carried out during such periods can then be scrutinized by alternative methods. One such method is to examine caseload complexity during the periods of apparent divergent performance compared with other periods.

CONCLUSIONS

These methods, while in no way representing formal statistical tests, provide a means that can alert surgeons to potential problems and help to identify sequences of cases that might benefit from further scrutiny.