Impact of cardiac intraoperative precursor events on adverse outcomes.

BACKGROUND: Although extensive study has been directed at the influence of patient factors and comorbidities on cardiac surgical outcomes, less attention has been focused on process. We sought to examine the relationship between intraoperative precursor events (those events that precede and are requisite for the occurrence of an adverse event) and adverse outcomes themselves. METHODS: Anonymous, prospectively collected intraoperative data was merged with database outcomes for 450 patients undergoing major adult cardiac operations. Precursor events were categorized by type, person most affected, severity, and compensation. Number and categories of precursor events were analyzed as predictors of a composite outcome combining death or near miss complications (DNM), using logistic regression. RESULTS: Precursor events occurred more frequently in cases with a DNM outcome than in those with no adverse event (2.7 +/- 2.4 vs 2.0 +/- 2.3/procedure, P = .005). After adjustment for other patient characteristics, the number of precursor events remained an independent predictor of DNM (RR, 1.14 per event [1.04 to 1.24]). Of 990 events, 35.6% related to management, 28.8% were technical, and 22.8% were environment-related. The surgeon was most affected in 40.8%, and 16.5% were of major severity. When categories of precursor events were analyzed, major severity events and those most affecting the surgeon were independent predictors of DNM. CONCLUSIONS: More detailed study of process in complex operations may lead to improved quality of care and patient safety. Special attention must be paid particularly to high risk patients and high risk precursor events.

Prospective assessment of intraoperative precursor events during cardiac surgery.

OBJECTIVE: Increasing attention has been afforded to the ubiquity of medical error and associated adverse events in medicine. There remains little data on the frequency and nature of precursor events in cardiac surgery, and we sought to characterize this. METHODS: Detailed, anonymous information regarding intraoperative precursor events (which may result in adverse events) was collected prospectively from six key members of the operating team during 464 major adult cardiac surgical cases at three hospitals and were analyzed with univariable statistical methods. RESULTS: During 464 cardiac surgical procedures, 1627 reports of problematic precursor events were collected for an average of 3.5 and maximum of 26 per procedure. 73.3% of cases had at least one recorded event. One-third (33.3%) of events occurred prior to the first incision, and 31.2% of events occurred while on bypass. While 68.0% of events were regarded as minor in severity (e.g., delays and missing equipment), a substantial proportion (32.0%) was considered major and included anastomotic problems, pump failure, and drug errors. Most problems (90.4%) were reported as being compensated for, although many (30.9%) were never discussed among the team. Major events were more likely to be discussed (p<0.0001) and less likely to have been previously encountered (p=0.0005). Perceptions of the severity and compensation of events varied across the team, as did temporal patterns of reporting (p<0.0001). CONCLUSIONS: A wide range of problematic precursor events occurs during the majority of cardiac surgery procedures. Attention to causes and ways of preventing these precursor events could have an impact on the rate of significant errors and improve the safety of cardiac surgery.

What constitutes optimal surgical revascularization? Answers from the Bypass Angioplasty Revascularization Investigation (BARI).

OBJECTIVES: The study was done to derive the optimum definition of complete revascularization in coronary artery bypass surgery. BACKGROUND: "Complete revascularization" has been considered the goal of coronary artery bypass operations, but various definitions of completeness exist. METHODS: We evaluated the Bypass Angioplasty Revascularization Investigation (BARI) surgical results in the seven years after operation. Different definitions of completeness of revascularization were retrospectively applied to the 1,507 patients in the combined randomized/registry group to derive the definition of complete operative revascularization with the best discrimination in long-term results between those with and without complete revascularization as defined. Four definitions were evaluated: 1) traditional complete revascularization with one graft to each major diseased artery system; 2) functional complete revascularization with one graft to all diseased major or primary segmental vessels; 3) number of distal anastomoses greater than, equal to or less than the number of diseased coronary segments; and 4) number of distal anastomoses to the major coronary systems equal to 1 or greater than 1. RESULTS: No independent survival advantage existed for traditional or functional complete revascularization as compared with incomplete revascularization. No survival advantage existed for any of the three arms of definition 3. For definition 4, seven-year death/myocardial infarction was highest (32.9%) when more than one anastomosis was constructed to any non-left anterior descending coronary artery (LAD) system (relative risk 1.37, p = 0.03). No increased risk was associated with constructing more than one anastomosis into the LAD system. CONCLUSIONS: The construction of more than one graft to any system other than the LAD appears to confer no long-term advantage, and may actually be deleterious.

Staged laparoscopic splenectomy and valve replacement in splenic abscess and infective endocarditis.

Splenic abscess is a rare clinical entity that is most commonly associated with infective endocarditis. Valve replacement in the setting of an unaddressed splenic abscess is associated with a high incidence of prosthetic valve infection and death. We describe 2 patients with infective endocarditis and splenic abscess treated by laparoscopic splenectomy followed by valve replacement.

Methods for reduction of sternal wound infection.

Deep sternal wound infections continue to be an uncommon but potentially devastating complication of cardiac surgical procedures. Numerous risk factors have been identified but only a few can be characterized as modifiable. These risk factors and their modifications are reviewed in the following article.

Experimental coronary artery occlusion: relevance to off-pump cardiac surgery.

Mechanical coronary artery occlusion is required for minimally invasive direct coronary artery bypass and off-pump coronary artery bypass surgery. It is important that the method of occlusion be minimally traumatic. Chronic effects of these methods have never been studied. Temporary occlusion of coronaries utilizing suture snare, silastic loop snare, and bulldog clamp was carried out in 12 Yucatan pigs. Three animals each were sacrificed acutely and at 3, 6, and 12 months. The area of occlusion of each vessel was examined by light microscopy and the degree of damage recorded. In the animals sacrificed acutely, there was more damage using the suture snare than with the other 2 methods, but there was minimal damage at longer intervals. There was slight damage acutely and chronically with the bulldog technique. No damage was seen acutely with the silastic loop technique, but some late damage was found. The techniques of coronary artery dissection and occlusion used for minimally invasive and off-pump bypass surgery may contribute to early postoperative graft occlusion.

An aortic cinch to quell suture line bleeding.

Bleeding from an aortic suture line or cannula site may be difficult to control, especially in the patient with a fragile or dilated aorta. This method of wrapping a vascular graft around the aorta to relieve tension on the suture line and control bleeding is simple and effective, and it facilitates obtaining the proper tension of the wrapped graft.

Severe, transient aortic insufficiency after bovine pericardial aortic valve replacement: a cautionary note.

Three patients demonstrated severe, central aortic insufficiency noted immediately upon removal of the aortic cross clamp after aortic valve replacement with a bovine pericardial Edwards Magna valve. After maintaining left ventricular decompression, the aortic insufficiency resolved in less than 1 hour. Knowledge of this phenomenon will prevent unnecessary prosthetic valve explantation and re-replacement.

Learning in a new cardiac surgical center: an analysis of precursor events.

BACKGROUND: Few studies of learning in the health care sector have analyzed measures of process, as opposed to outcomes. We assessed the learning curve for a new cardiac surgical center using precursor events (incidents or circumstances required for the occurrence of adverse outcomes). METHODS: Intraoperative precursor events were recorded prospectively during major adult cardiac operations, categorized by blinded adjudicators, and counted for each case (overall and according to these categories). Trends in the number of precursor events were analyzed by hospital and by defining 10 equal-sized groups across time, as were trends in outcomes obtained from institutional databases. Results from the first 101 cases performed at a new cardiac surgical site (hospital A) were compared with 2 established centers. RESULTS: A steep reduction in the total number of precursor events over time was observed in the early experience of hospital A (9.2 +/- 4.9 to 2.0 +/- 1.2 events per case, from first to last decile of time, P(trend) < .0001) compared with qualitatively stable levels in the other hospitals; this reduction was driven largely by decreases in the minor severity (P(trend) < .0001), compensated (P(trend) < .0001), and environment (P(trend) < .0001) categories of precursor events. No detectable changes over time were observed in postoperative mortality and complications. No significant improvement was observed in patient comorbid conditions or medical status over time to explain the trend in hospital A. CONCLUSION: Analyzing and targeting specific kinds of process-related failures (precursor events) may provide a novel and sensitive means of tracking, deconstructing, and optimizing organizational learning in medicine.

Intermediate-term outcomes of surgical atrial fibrillation correction with the CryoMaze procedure.

BACKGROUND: Few studies have reported long-term outcomes of surgical atrial fibrillation (AF) correction. We perform the Cox-Maze III lesion set with argon-powered cryoenergy (CryoMaze procedure) on all patients with AF presenting for cardiac operations. This study reports long-term clinical results and heart rhythm status. METHODS: Between July 2002 and November 2005, 119 consecutive patients underwent surgical AF correction with the CryoMaze procedure. Mitral valve disease was the primary indication for operation in 66%. AF was continuous in 65%. Rhythm assessment was with 2-week continuous electrocardiographic (ECG) monitoring in 75% of patients and by noncontinuous ECG in the remainder. Median follow-up was 3.2 years and was 98% complete. RESULTS: There was one hospital (0.8%) death. Survival at 3 years was 84%. One perioperative stroke resolved completely. No late strokes occurred. In 4 of 119 patients (4 (3.4%), pacemakers were inserted during the index hospitalization. Median length of stay was 7 days. Overall freedom from AF more than 3 years after operation was 60%. Among patients with preoperative intermittent AF, 85% (28 of 33) were in normal sinus rhythm, and 47% (27 of 58) with continuous AF were in normal sinus rhythm (p < 0.001). CONCLUSIONS: CryoMaze AF correction is safe and is associated with a very low risk of stroke. Rates of normal sinus rhythm at more than 3 years postoperatively were high for patients with intermittent AF and acceptable for those with continuous AF. This experience supports wider application of the CryoMaze to all patients with AF who need cardiac operations.

Origin of the left anterior descending coronary artery from the pulmonary artery: An unusual cause of angina in a middle-aged woman.

A 48-year-old woman was admitted to our institution with angina pectoris and a systolic murmur. At cardiac catheterization, she was found to have an anomalous origin of the left anterior descending coronary artery from the pulmonary trunk. There was also an associated atrial septal defect and a bicuspid aortic valve.

Multiparameter fiber optic sensor for the assessment of intramyocardial perfusion.

OBJECTIVES: The objective of this study was to characterize a multiparameter fiber optic sensor for detection of changes in intramyocardial perfusion and to demonstrate a method of determining critical values for pH, PCO2, and PO2 to indicate onset of anaerobic metabolism. METHODS: Six swine underwent a 20-minute occlusion of the left anterior descending coronary artery (LAD). Myocardial pH, PCO2, and PO2 were measured continuously in the LAD and left circumflex coronary artery (CFX) territories. Critical values for each parameter were calculated from these data. RESULTS: During occlusion LAD myocardial pH declined from 7.36 +/- 0.04 to 6.85 +/- 0.04; PCO2 rose from 57.0 +/- 2.9 to 154.0 +/- 18.0 torr, PO2 fell from 78 +/- 20 to 6 +/- 5 torr. No myocardial pH or PCO2 changes were observed in the CFX region, however, CFX PO2 was affected in some animals during LAD occlusion and release. Methods for determining the ischemic threshold from these sensor data are presented. CONCLUSIONS: Multiparameter fiber optic sensors reliably respond to coronary occlusion and thus have the potential to help guide myocardial protection strategies for both on- and off-pump cardiac surgery.

Noninvasive, near infrared spectroscopic-measured muscle pH and PO2 indicate tissue perfusion for cardiac surgical patients undergoing cardiopulmonary bypass.

OBJECTIVE: To determine whether near infrared spectroscopic measurement of tissue pH and Po2 has sufficient accuracy to assess variation in tissue perfusion resulting from changes in blood pressure and metabolic demand during cardiopulmonary bypass. DESIGN: Prospective clinical study. SETTING: Academic medical center. SUBJECTS: Eighteen elective cardiac surgical patients. INTERVENTION: Cardiac surgery under cardiopulmonary bypass. MEASUREMENTS AND MAIN RESULTS: A near infrared spectroscopic fiber optic probe was placed over the hypothenar eminence. Reference Po2 and pH sensors were inserted in the abductor digiti minimi (V). Data were collected every 30 secs during surgery and for 6 hrs following cardiopulmonary bypass. Calibration equations developed from one third of the data were used with the remaining data to investigate sensitivity of the near infrared spectroscopic measurement to physiologic changes resulting from cardiopulmonary bypass. Near infrared spectroscopic and reference pH and Po2 measurements were compared for each subject using standard error of prediction. Near infrared spectroscopic pH and Po2 at baseline were compared with values during cardiopulmonary bypass just before rewarming commenced (hypotensive, hypothermic), after rewarming (hypotensive, normothermic) just before discontinuation of cardiopulmonary bypass, and at 6 hrs following cardiopulmonary bypass (normotensive, normothermic) using mixed-model analysis of variance. Near infrared spectroscopic pH and Po2 were well correlated with the invasive measurement of pH (R2 =.84) and Po2 (R 2 =.66) with an average standard error of prediction of 0.022 +/- 0.008 pH units and 6 +/- 3 mm Hg, respectively. The average difference between the invasive and near infrared spectroscopic measurement was near zero for both the pH and Po2 measurements. Near infrared spectroscopic Po2 significantly decreased 50% on initiation of cardiopulmonary bypass and remained depressed throughout the bypass and monitored intensive care period. Near infrared spectroscopic pH decreased significantly during cardiopulmonary bypass, decreased significantly during rewarming, and remained depressed 6 hrs after cardiopulmonary bypass. Diabetic patients responded differently than nondiabetic subjects to cardiopulmonary bypass, with lower muscle pH values (p =.02). CONCLUSIONS: Near infrared spectroscopic-measured muscle pH and Po2 are sensitive to changes in tissue perfusion during cardiopulmonary bypass.