Aprotinin and perioperative complications in cardiac surgery.

AIM: Recently, the clinical significance of aprotinin-induced renal dysfunction and other end-organ complications in patients undergoing cardiac surgery has engendered substantial controversy. Therefore, we assessed the effect of aprotinin on end-organ complications in patients undergoing cardiac surgery. METHODS: Data of 674 patients (mean age 65.4 +/- 11.0 years, 457 males) undergoing cardiac surgery between January 1 and December 31, 2005 at Semmelweis University were used for the analyses. Preoperative, intraoperative and postoperative clinical and surgical variables were recorded. Patients administered aprotinin received the drug either as a low-dose regimen, a loading dose of 1 million kallikrein-inhibitor units (KIU), 1 million KIU in pump, and 1 million KIU post pump (or continuous infusion of 0.25 million KIU per hour); or a high-dose regimen, a loading dose of 2 million KIU, 2 million KIU in pump, and 2 million KIU post pump (or continuous infusion of 0.5 million KIU per hour). The outcomes were renal complications defined as a 25% reduction in postoperative calculated creatinine clearance compared to the preoperative baseline or renal failure requiring dialysis; and the composite of renal, cardiovascular and cerebrovascular complications and all-cause mortality. RESULTS: Patients underwent coronary artery bypass surgery (63%), valvular (27%) or a combination (5%) and surgery on the ascending aorta (5%). There were 550 patients (81.6%) who received aprotinin treatment. In multivariate regression analyses when the relation between high or low dose aprotinin compared to no aprotinin was evaluated, the likelihood of renal complications [high dose: odds ratio (OR)=1.4, 95% confidence interval (CI), 0.6-3.0, P=0.4; low dose: OR=1.2, 95%CI, 0.7-2.3, p=0.5], and the composite outcome variable (high dose: OR=1.6, 95%CI, 0.8-3.4, P=0.2; low dose: OR=1.3, 95%CI, 0.7-2.3, P=0.4) were not significantly increased. CONCLUSION: Our analysis suggests that aprotinin use in either a high or low dose regimen was not associated with an increase in adverse end-organ complications.

Myocardial ischemia. Monitoring to diagnose ischemia: how do I monitor therapy?

Diagnosis of myocardial ischemia requires integration of ECG, pulmonary artery pressures, and TEE data. ST depression of 1 mV or elevation of 2 mV remains the mainstay of diagnosis of ischemia. Increases of pulmonary artery pressures of 5 mm Hg are common but not reliably diagnostic of ischemia. Transesophageal echocardiography is the most sensitive monitor of ischemia, where the spectra of SWMA evolve. Diastolic dysfunction (elevations in LVEDP) is a more sensitive marker of ischemia, but requires measurement of several Doppler patterns. After diagnosis, treatment should include optimization of hemodynamics (beginning with beta-blockers and nitrates), anesthesia, and oxygen-carrying capacity (e.g., normothermia, oxygen saturation, hematocrit more than 28%).

Association of fast-track cardiac management and low-dose to moderate-dose glucocorticoid administration with perioperative hyperglycemia.

OBJECTIVE: To delineate associations between preoperative risk factors and clinical processes of care and perioperative glucose tolerance in patients managed on a fast-track cardiac surgery clinical pathway with prebypass methylprednisolone administration. DESIGN: Retrospective sequential cohort study. SETTING: University-affiliated Department of Veterans Affairs medical center. PARTICIPANTS: Fast-track patients (n = 293; n = 72 low-dose methylprednisolone [100-125 mg]; n = 221 moderate-dose methylprednisolone [500 mg]) plus pre-fast-track patients (n = 258; no methylprednisolone) undergoing cardiac surgery with cardiopulmonary bypass. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Multivariate linear regression was used to model the association of 17 preoperative risk and intraoperative process-of-care variables with serum glucose concentration on arrival in the intensive care unit. Preoperative serum glucose concentrations were not significantly different among the pre-fast-track, fast-track with low-dose methylprednisolone, and fast-track with moderate-dose methylprednisolone cohorts (129 +/- 54, 137 +/- 55, 127 +/- 46 mg/dL [mean +/- SD]). Postoperative serum glucose concentrations were significantly different (171 +/- 58, 223 +/- 56, 250 +/- 75 mg/dL; p < 0.03, for all pairwise comparisons). Using backward elimination from the full 17-variable multivariate model (R-square = 0.63), 4 variables remained significant (all p < 0.0001; R-square = 0.60): (1) Preoperative diabetes status (adjusted mean post-operative glucose level, mg/dL; [95% confidence interval (CI)]): no treatment, 193 (188-199); oral agent, 276 (262-291); insulin requiring, 301 (283-320); (2) steroid group: pre-fast-track, 201 (195-209), fast-track with low-dose methylprednisolone, 271 (256-287); fast-track with moderate-dose methylprednisolone, 295 (284-306); (3) volume of glucose-containing cardioplegia (beta coefficient, 95% CI): 2.22% (1.37-3.10) increase per 100 mL; and (4) intraoperative epinephrine infusion: none, 231 (224-239); yes, 276 (264-288). No significant interactions were identified. No significant effect of opioid dose was observed. CONCLUSION: At this institution, implementation of the fast-track pathway was associated with a deterioration of glucose tolerance. Preoperative diabetes, pre-cardiopulmonary bypass administration of steroids, volume of glucose-containing cardioplegia solution administered, and use of epinephrine infusions were significantly associated multivariate factors.

Stroke in cardiac surgical patients: determinants and outcome.

BACKGROUND: Despite improving outcomes in cardiac surgical patients, stroke continues to remain a major complication. Few prospective studies are available on postoperative stroke. The present study was conducted to elucidate the incidence and predictors of stroke in a large group of cardiac surgical patients. METHODS AND RESULTS: Prospective data collected on 4,941 patients undergoing cardiac surgery were subjected to univariate and logistic regression analyses (98.4% men; 72% older than 60 years; 9.1% with history of prior stroke; 80.4% underwent isolated coronary artery bypass grafting). Stroke predictors include history of stroke and hypertension, older age, systolic hypertension, bronchodilator and diuretic use, high serum creatinine, surgical priority, great vessel repair, use of inotropic agents after cardiopulmonary bypass, and total cardiopulmonary bypass time (p < 0.05 for all comparisons). Median intensive care unit and hospital stays were longer, and hospital mortality and 6-month mortality were higher for patients with stroke (p < 0.001). CONCLUSIONS: Stroke after cardiac surgical procedures is a morbid event. Identification of predictors and development of strategies to modify these factors should lead to a lower incidence of stroke.

Early extubation following cardiac surgery in a veterans population.

BACKGROUND: Early tracheal extubation is an important component of the "fast track" cardiac surgery pathway. Factors associated with time to extubation in the Department of Veterans Affairs (DVA) population are unknown. The authors determined associations of preoperative risk and intraoperative clinical process variables with time to extubation in this population. METHODS: Three hundred four consecutive patients undergoing coronary artery bypass graft, valve surgery, or both on a fast track clinical pathway between October 1, 1993 and September 30, 1995 at a university-affiliated DVA medical center were studied retrospectively. After univariate screening of a battery of preoperative risk and intraoperative clinical process variables, stepwise logistic regression was used to determine associations with tracheal extubation < or = 10 h (early) or > 10 h (late) after surgery. Postoperative lengths of stay, complications, and 30-day and 6-month mortality rates were compared between the two groups. RESULTS: One hundred forty-six patients (48.3%) were extubated early; one patient required emergent reintubation (0.7%). Of the preoperative risk variables considered, only age (odds ratio, 1.80 per 10-yr increment) and preoperative intraaortic balloon pump (odds ratio, 7.88) were multivariately associated with time to extubation (model R) ("late" association is indicated by an odds ratio >1.00; "early" association is indicated by an odds ratio <1.00). Entry of these risk variables into a second regression model, followed by univariately significant intraoperative clinical process variables, yielded the following associations (model R-P): age (odds ratio, 1.86 per 10-yr increment), sufentanil dose (odds ratio, 1.54 per 1-microg/kg increment), major inotrope use (odds ratio, 5.73), platelet transfusion (odds ratio, 10.03), use of an arterial graft (odds ratio, 0.32), and fentanyl dose (odds ratio, 1.45 per 10-microg/kg increment). Time of arrival in the intensive care unit after surgery was also significant (odds ratio, 1.42 per 1-h increment). Intraoperative clinical process variables added significantly to model performance (P < 0.001 by the likelihood ratio test). CONCLUSIONS: In this population, early tracheal extubation was accomplished in 48% of patients. Intraoperative clinical process variables are important factors to be considered in the timing of postoperative extubation after fast track cardiac surgery.

Cardiac entrapment during minimally invasive aortic valve replacement.

Reduced exposure during minimally invasive valve operations poses new difficulties in intraoperative management. Transesophageal echocardiography improves intraoperative management. During a minimally invasive aortic valve replacement, we encountered unexpected hypotension due to mechanical compression of the right ventricle against the sternum. Transesophageal echocardiography facilitated rapid diagnosis of this problem. Surgeons performing these procedures should be aware of this potential problem.

Fast-track cardiac surgery in a Department of Veterans Affairs patient population.

BACKGROUND: "Fast-track" (FT) cardiac surgery is popular in the private and university sectors. This study was designed to examine its safety and efficacy in the Department of Veterans Affairs elderly, male patient population, a population with multiple comorbid risk factors, often decreased social functioning, and impaired support systems. METHODS: Time to extubation, hospital length of stay, perioperative morbidity, and mortality were studied in two consecutive cohorts undergoing cardiac operations requiring cardiopulmonary bypass before (pre-FT: n = 255, January 1992 to September 1993) and after (FT: n = 304, October 1993 to October 1995) institution of an FT protocol at a university-affiliated teaching Department of Veterans Affairs medical center. Preoperative risk factors, including a Department of Veterans Affairs risk-adjusted estimate of operative mortality, and perioperative surgical and anesthetic processes of care were evaluated. RESULTS: The mean Department of Veterans Affairs risk estimate of perioperative mortality was not different between the pre-FT and FT cohorts (3.5% versus 3.7%, p = 0.13). In the FT cohort, median time to extubation decreased significantly (19.2 versus 10.2 hours; p < 0.001) along with median surgical intensive care unit stay (96 versus 49 hours; p < 0.001) and total postoperative length of stay (222 versus 167 hours; p < 0.001). Median postoperative day of hospital discharge decreased from day 10 to 7 (p < 0.001). One patient (0.3%) required emergent reintubation directly related to early extubation. Reintubation for medical reasons was unchanged between pre-FT and FT groups (6.3% versus 5.0%; p = 0.48). Postoperative morbidity was similar between groups except for nosocomial pneumonia, the rate of which decreased significantly in the FT cohort (14.7% versus 7.3%; p < 0.005). Thirty-day (3.9% versus 4.6%; p = 0.69) and 6-month mortality (6.7% versus 6.9%; p = 0.91) were unchanged. CONCLUSIONS: An FT cardiac surgery protocol has been instituted in a university-affiliated teaching Department of Veterans Affairs medical center, with decreased length of stay and no significant increase in postoperative morbidity, 30-day mortality, or 6-month mortality. It was associated with a lower rate of nosocomial pneumonia, a finding that must be validated in a prospective study.

Changes in blood coagulation during and following cardiopulmonary bypass: lack of correlation with clinical bleeding.

Although previous studies have documented a wide variety of derangements in laboratory measurements of blood coagulation and platelets during cardiopulmonary bypass, limited data are available concerning the magnitude of these changes and any association with excessive bleeding. To determine whether abnormalities in commonly available laboratory tests for the evaluation of coagulation, fibrinolysis and hemostasis correlate with postoperative blood loss and transfusion requirements as measures of clinical outcome, 47 consecutive patients undergoing coronary artery bypass grafting with hypothermic cardiopulmonary bypass (CPB) were studied prospectively at 12 time points before, during, and following CPB. Routine blood coagulation tests, coagulation factor levels (fibrinogen, V, VII, VIII, and IX) and fibrinolysis (FDP) became abnormal within 15 minutes after patients were placed on CPB, remained abnormal for the duration of CPB, and recovered at varying rates after discontinuation of CPB. Mean factor V levels declined by the greatest percentage, to 15% of normal, followed by factor VIII which decreased to 30%. Platelet counts declined to below 100 x 10(9)/L after the initiation of CPB and remained low in the postoperative period. Twenty-eight percent of patients had mediastinal output > or = 100 mL per hour during the immediate postoperative period, and were considered to be "bleeders." There were no clinically relevant differences in any of the laboratory measurements between patients with normal postoperative blood loss and those defined as bleeders. Thus, the absence of significant correlations between various laboratory measurements of hemostasis and actual postoperative bleeding indicates that these laboratory derangements are transient, are not predictive of clinically important hemostatic abnormalities, and should not be used in isolation to guide the use of blood components in these patients. Furthermore, although bleeders received more blood components, there was surprisingly little effect on the coagulation factor levels measured.

Validation testing of the SEER real-time digital holter monitor.

OBJECTIVES: Perioperative myocardial ischemia, detected by off-line Holter ST-segment monitoring, has been associated with adverse cardiac outcome. Technical advances in digital signal processing have facilitated development of digital Holter recorders that allow 24- to 48-hour recording, full disclosure storage, and "real-time" quantitative analysis of ST-segment levels. These recorders may be useful for "on-line" clinical detection of perioperative ischemia. However, little data are available, independent of manufacturers' claims, to validate their accuracy. Using a previously validated digital electrocardiogram (ECG) simulator, a commercially available device was evaluated. DESIGN: Laboratory bench study. SETTING: Not applicable. PARTICIPANTS: Not applicable. INTERVENTIONS: Not applicable. MEASUREMENTS AND MAIN RESULTS: Custom digital ECG waveform templates were programmed for use with a commercially available ECG simulator (M311 ECG simulator; Fogg Systems, Inc, Aurora, CO). For each template, ST-segment morphology (horizontal elevation or depression, downsloping depression), QRS duration (80 v 120 msec) and the presence or absence of a P wave were manipulated, yielding six unique QRS shapes. For each shape, the degree of ST-segment deviation was altered over a wide range. ST-segment values from the simulator (measured at 60 msec after the J point) ranged from +10 to -18 mm. The SEER digital Holter recorder (Marquette Electronics, Milwaukee, WI) was tested. One hundred twenty-six measurements of ST-segment deviation were input to the SEER at each of two testing sessions. The ST-segment value from the recorder in the "noninteractive" analysis mode was obtained, and the two results averaged for comparison with the expected simulator value. Variability of ST-segment measurement over a continuous 1-hour period of simulator input was also assessed. Sixty-seven percent of measurements were within 95% to 100% of expected, whereas 90% were within 90% to 110%. The regression equation for the complete dataset was SEER output (mm) = -0.47 + 1.015 * simulator input, R2 = 0.99. The mean observed-to-expected value ratio was 100% +/- 6% (+/-SD), range 80% to 114%. The mean deviation in millimeters from expected for all measurements was 0.10 +/- 0.20 mm, median 0.05 mm, range -0.25 to +0.60 mm. For the 72 measurements obtained by 5-minute sampling over 1 hour of continuous simulator input for each of the six QRS shapes, the mean percent difference between observed and expected values was 0.5% +/- 4.5%, median 0.0%, with a mean coefficient of variation of 2.7% (median 1.9%). CONCLUSIONS: Using a digital ECG simulator, it was found that the SEER recorder analyzed ST-segment deviation with a high degree of accuracy. These findings, along with its full disclosure reporting capabilities, suggest it may be useful in perioperative risk stratification. However, accuracy in the clinical setting remains to be validated.

Validation testing of the spacelabs PC2 ST-segment analyzer.

OBJECTIVES: Recent studies have demonstrated that perioperative myocardial ischemia, detected by electrocardiography, is a risk factor for myocardial infarction. ST-segment analyzers and hemodynamic monitors may be useful for on-line detection in perioperative and critical care environments. However, independent performance and accuracy standards for these devices have not been established. Therefore, a testing protocol was developed using an electrocardiogram (ECG) simulator that allowed selectively altered ST-segment displacement, in a calibrated fashion over a wide range. DESIGN: Laboratory bench study. SETTING: Not applicable. PARTICIPANTS: Not applicable. INTERVENTIONS: Not applicable. MEASUREMENTS AND MAIN RESULTS: Custom digital ECG waveform templates were programmed for use with a commercially available ECG simulator (M311 ECG simulator; Fogg Systems, Inc., Aurora, CO). For each template, ST-segment morphology (horizontal elevation or depression, downsloping depression), QRS duration, and the presence or absence of a P wave were manipulated, resulting in seven different QRS shapes. Within each shape, the degree of ST-segment deviation was altered over a wide range. A PC2 Bedside Monitor (SpaceLabs Inc., Redmond, WA) was tested. One hundred forty-eight measurements of ST-segment deviation input from the simulator were made at each of two testing sessions. The first ST-segment value displayed by the analyzer was recorded, and the two measurements averaged for comparison. Placement of the J-point, J + 60 msec, and isoelectric reference points by the analyzer were evaluated. Simulator output was validated for accuracy and stability. Subtle errors in placement of the J-point marker were observed in all seven QRS shapes. These errors usually did not alter placement of the isoelectric marker before, but not exactly at the beginning of, the R-wave upstroke. Thus, ST-segment values returned by the monitor (J + 60 msec - isoelectric reference value) were unaffected. However, in two QRS shapes, the isoelectric point was displaced onto the upstroke of the R wave, resulting in erroneous ST-segment values. In one, the error may have been caused by the difference in QRS duration of that template (120 msec) relative to the fixed 115-msec interval from the J point used by the analyzer and was present in all points tested. In the second (normal QRS duration), the error was present in some, but not all points tested (4/21, 24%). All QRS shapes with proper placement of the isoelectric point returned ST-segment values within +/- 0.5 mm of expected, and 98% were within +/- 0.25 mm of expected. The mean difference between observed and expected ST-segment values for 100 measurements with normal QRS duration and proper isoelectric point placement was 0.08 mm +/- 0.07 mm (SD). CONCLUSIONS: The bench results suggest that visual confirmation of ST-segment analyzer values may be advisable in the clinical setting. Although most complexes with normal conduction and a P wave are likely to be accurately analyzed, those with prolonged QRS duration were problematic. The simulator protocol may be helpful in ensuring accuracy of ST-segment analyzers, especially in their early development stages.

The Processes, Structures, and Outcomes of Care in Cardiac Surgery study protocol.

Recently, a growing interest has arisen in defining and measuring health care outcomes. Although outcome measures may be used as potential quality-of-care screens, outcomes cannot indicate directly how care might be improved. Thus, the Processes, Structures, and Outcomes of Care in Cardiac Surgery (PSOCS) study was designed to investigate the linkages between the processes and structures of care with risk-adjusted outcomes for cardiac surgery care. Data are being collected on a comprehensive array of risk factors, processes, structures, and outcomes of care at 14 Veterans Affairs Medical Centers for this prospective, observational study. Approximately 6,000 cardiac surgery patients will be enrolled in this study over a 4.5-year period. Patient selection is based on a 6 workday rotating sampling frame with an oversampling of emergent patients. During the study, a register of all patients undergoing cardiac surgery at these centers is being maintained to assess the overall context of patient recruitment. The study will continue to enroll patients through December 1996. Major study end points extend beyond traditional measures of 30-day mortality and morbidity to encompass more innovative intermediate outcome measures, including changes in physical functional status and health-related quality of life.

Relationships between patient-related risk factors, processes, structures, and outcomes of cardiac surgical care. Conceptual models.

The processes, Structures, and Outcomes of Care in Cardiac Surgery (PSOCS) study involves data collection on a comprehensive array of patient risk factors, processes, structures, and short-term outcomes of care at 14 participating Veterans Administration medical centers. This article summarizes the PSOCS conceptual models that serve as the theoretical framework for analyzing the hypothesized risk-process-structure-outcome relationships being investigated. The PSOCS data set includes more than 1,100 variables related to each patient and more than 300 variables related to provider-specific and facility-specific characteristics. This massive data set presents a formidable analytic challenge. The conceptual modeling process involved four-steps: 1) establishing a vision of the general conceptual model defining the overall risk-process-structure-outcome relationships, 2) developing specific hypotheses or subhypotheses, 3) visualizing a hierarchical set of dimensions and subdimensions, and 4) uniquely assigning each variable collected in the study to a dimension or subdimension for purposes of testing the study's primary hypotheses. A multidisciplinary team participated in this modeling process. The goal of the conceptual modeling process is to identify clearly the actions (ie, the changes in either processes or structures that are linked to risk-adjusted patient outcomes) that can be taken by clinicians, management, and policymakers to improve the quality of cardiac surgical care.

Variations in the processes and structures of cardiac surgery nursing care.

Nurses play an invaluable role as key members of the cardiac surgery patient's medical care team. Over the last century, the nursing profession has become more independent and autonomous. Despite the widespread use of nursing quality indicators, the effect of nursing-specific processes and structures of care on patient outcomes is unknown. Thus, the Processes, Structures, and Outcomes of Care in Cardiac Surgery (PSOCS) study was initiated, in part, to determine the potential effect of nursing processes and structures of care on cardiac surgery patients' risk-adjusted outcomes. In this article, the authors summarize the key components of nursing structures of care incorporated in the PSOCS study. Nursing process variables were not sufficiently designed into the study to address hypotheses relating nursing care processes to patient outcomes. An analysis of the pilot test data from September 1992 to September 1993 demonstrated potentially important variations between the six pilot centers regarding nursing care provider profiles (eg, educational preparation, specialty certification, and experience levels) and nursing staff ratios (eg, within the surgical intensive care unit). When linked to risk-adjusted patient outcomes, these variations in nursing structure of care may offer important insights toward improving the quality of care of cardiac surgery patients.

Evaluating anesthesia health care delivery for cardiac surgery. The role of process and structure variables.

Anesthesia care is an integral component of cardiac surgery. Emphasis on cost-effectiveness and decreased hospital stay has prompted reevaluation of anesthesia practice. However, the role of anesthesia process and structure variables in relation to patient outcomes is largely unknown. Processes, Structures and Outcomes of Care in Cardiac Surgery is the first epidemiologic study to collect data on anesthesia processes, such as the pharmacologic components of anesthesia and types of cardiovascular monitors used. Structures of care, such as resident staffing, supervision, completeness of documentation, and training and experience of care providers, are also being assessed. Pilot data collected from September 1992 to September 1993 demonstrate substantial variation between the six study sites in selected processes and structures. Despite the near-universal use of narcotic anesthesia as the primary anesthetic technique, variation in the type of opioid and adjuvant benzodiazepine used was observed. Regarding invasive hemodynamic monitoring, most centers used only one type of catheter. Intraoperative transesophageal echocardiography was used commonly at several centers for valve surgery, whereas other centers did not use it at all. Its use during coronary artery bypass grafting was less common. Assessment of the preoperative anesthesia note revealed that coronary anatomy and ventricular function were noted in nearly all instances. However, a clear notation that risks and benefits of anesthesia were discussed was less frequent. Structures related to anesthesia attending staffing, board certification, and experience revealed variation. Some sites had smaller and/or more experienced attending staffs, whereas others had larger and/or less experienced staffs. These pilot findings appear to validate the authors' hypotheses that variations in anesthesia practice are present within the Veterans Affairs system. They suggest that the variable set is robust enough to relate processes and structures of anesthesia care to patient outcome.

Self-report measures for assessing treatment outcomes in cardiac surgery patients.

Patient self-report measures are increasingly valued as outcome variables in health services research studies. In this article, the authors describe the Functional Status, Health Related Quality of Life, Life Satisfaction, and Patient Satisfaction scales included in the Processes, Structures, and Outcomes of Cardiac Surgery (PSOCS) cooperative study underway within the Department of Veterans Affairs health care system. In addition to reporting on the baseline psychometric characteristics of these instruments, the authors compared preoperative Medical Outcomes Study SF-36 data from the study patients with survey data from a probability sample of the US population and with preoperative data on cardiac surgery patients from a high volume private sector surgical practice. Descriptive analyses indicate that the SF-36 profiles for all of the cardiac patients are highly similar. The Veterans Affairs and private sector patients report diminished physical functioning, physical role functioning, and emotional role functioning as well as reduced energy relative to an age-matched comparison sample. At the same time, however, the Veterans Affairs patients evidenced lower levels of capacity on most of the SF-36 dimensions relative to the private sector patients.

Advances in anesthesia monitoring.

Technological advances in monitoring for anesthesia continue to provide clinicians with an increasing amount of physiologic information for critical intraoperative decision making. This expanded set of physiologic data not only makes routine surgery safer from rare, but potentially fatal, anesthetic or surgical mishaps; it also facilitates surgery on very high risk patients. However, it must be emphasized at the onset that anesthesia monitoring is probably more appropriately termed perioperative or critical care monitoring, since many of these advances are applicable in the critical care units as well.

The safety and efficacy of ten percent pentastarch as a cardiopulmonary bypass priming solution. A randomized clinical trial.

Ten percent pentastarch is a low-molecular-weight hydroxyethyl starch with greater oncotic pressure and shorter intravascular persistence than 6% hetastarch. To evaluate its safety and efficacy as a component of cardiopulmonary bypass priming solution, we prospectively studied 90 patients undergoing coronary artery bypass grafting or valve replacement necessitating cardiopulmonary bypass (bubble oxygenator and moderate systemic hypothermia). Sixty patients were randomized to receive 75 gm of either 10% pentastarch (group P) or 25% albumin (group A), and 30 patients received lactated Ringer's solution alone (group C). Intravascular colloid osmotic pressure during cardiopulmonary bypass was highest with either of the colloid primes (15-minute measurement: group P, 15.7 +/- 2.2 mm Hg (mean +/- standard deviation); group A, 15.2 +/- 2.0 mm Hg; group C, 11.3 +/- 1.7 mm Hg; p less than 0.05, groups P and A compared with group C). This was associated with a lower volume requirement during cardiopulmonary bypass to maintain the venous reservoir (group P, 333 +/- 318 ml; group A, 483 +/- 472 ml; group C, 1332 +/- 1013 ml; p less than 0.05, groups P and A compared with group C). Urine output during cardiopulmonary bypass was similar in each group. Net intraoperative fluid balance was lowest in the colloid groups (groups P and A, 5.7 +/- 1.4 L; group C, 6.9 +/- 1.3 L; p less than 0.05, groups P and A compared with group C). Cardiac index shortly after weaning from cardiopulmonary bypass was greatest in group P (group P, 3.2 +/- 0.9; group A, 2.8 +/- 0.8; group C, 2.7 +/- 0.6 dyne.sec.cm-5; p less than 0.05, group P compared with group C). Changes in alveolar-arterial oxygen gradients, shunt fraction, and effective compliance were similar in all groups. During cardiopulmonary bypass, pentastarch appeared to cause the greatest degree of hemodilution, as suggested by the lowest hemoglobin, factor VII and IX levels and platelet count. The activated partial thromboplastin time was significantly prolonged during and immediately after cardiopulmonary bypass in group P relative to groups A and C (p less than 0.05), although there were no significant differences in the activated clotting time before cardiopulmonary bypass, during cardiopulmonary bypass, or after heparin neutralization. As well, clinical indices of hemostasis, including mediastinal drainage, red cell, platelet, and fresh frozen plasma requirements, and reoperation for excessive postoperative bleeding, were similar. We conclude that pentastarch, when used in cardiopulmonary bypass prime, is as safe as either albumin or Ringer's solution alone.(ABSTRACT TRUNCATED AT 400 WORDS)

Monitoring for myocardial ischemia during noncardiac surgery. A technology assessment of transesophageal echocardiography and 12-lead electrocardiography. The Study of Perioperative Ischemia Research Group.

OBJECTIVE: Transesophageal echocardiography (TEE) and 12-lead electrocardiography (ECG) are sophisticated techniques that are increasingly being used to monitor for myocardial ischemia during noncardiac surgery. We examined whether the routine use of these techniques has incremental clinical value in identifying patients at high risk for perioperative ischemic outcomes when compared with preoperative clinical data and intraoperative monitoring using continuous two-lead bipolar ECG. DESIGN: Cohort study. SETTING: Veterans Affairs medical center. PATIENTS: A total of 332 men undergoing noncardiac surgery who had or were at high risk for coronary artery disease. INTERVENTIONS: TEE, 12-lead ECG, and two-lead ECG were performed continuously during noncardiac surgery (47% vascular, 53% nonvascular). Monitoring results were not available to anesthesiologists or surgeons, and data were blindly analyzed after surgery. MAIN OUTCOME MEASURE: Perioperative ischemic outcomes (cardiac death, nonfatal myocardial infarction, unstable angina). RESULTS: In a subset of 285 patients who were adequately studied by all three techniques, 111 patients (39%) were identified as having intraoperative myocardial ischemia (by one or more monitoring techniques). By univariate analysis, intraoperative ischemia was associated with all perioperative cardiac outcomes, including ischemic outcomes, congestive heart failure, and ventricular tachycardia (P less than or equal to .02 for each of the three monitoring techniques). However, when monitoring results for TEE and 12-lead ECG were added to a multivariate model that included preoperative clinical data and continuous two-lead ECG results, the incremental value of TEE was small (odds ratio, 2.6; 95% confidence interval [CI], 1.2 to 5.7; P = .02) and that of 12-lead ECG was not significant (odds ratio, 1.5; 95% CI, 0.6 to 3.8). Furthermore, when the multivariate analysis was repeated with only ischemic outcomes, neither TEE nor 12-lead ECG retained significant associations (odds ratio, 2.2; 95% CI, 0.5 to 9.4, and odds ratio, 1.1; 95% CI, 0.2 to 6.1, respectively). CONCLUSION: When compared with preoperative clinical data and intraoperative monitoring using two-lead ECG, routine monitoring for myocardial ischemia with TEE or 12-lead ECG during noncardiac surgery has little incremental clinical value in identifying patients at high risk for perioperative ischemic outcomes.