Morbidity outcome in early versus conventional tracheal extubation after coronary artery bypass grafting: a prospective randomized controlled trial

Non-steroidal anti-inflammatory drugs in treatment of postoperative pain after cardiac surgery

PURPOSE

Non-steroidal anti-inflammatory drugs (NSAIDs) are used as analgesic in postoperative pain to reduce opioid side effects, such as drowsiness and nausea. However, NSAIDs have not been used extensively in cardiac surgical patients due to the fear of untoward effects on gastric, renal, and coagulation parameters. This study will evaluate the efficacy and safety of three NSAIDs for pain control in CABG patients.

METHODS

One hundred and twenty patients scheduled for elective CABG surgery were enrolled in randomized, double blind, controlled study. Standardized fast track cardiac anesthesia was used. One dose of drug (75 mg diclofenac, 100 mg ketoprofen, 100 mg indomethacin, or placebo) was given pr one hour before tracheal extubation and a second dose 12 hr later. Pain was treated with morphine iv and acetaminophen po. Visual analogue pain scores were recorded at baseline, 3, 6, 12 and 24 hr after the first dose of drug.

RESULTS

There were no differences among the groups in pain scores. Only patients who received diclofenac required less morphine than patients in the control group (P < 0.05). When the total amounts of pain medications were computed to morphine equivalents, only patients in the diclofenac group received less pain medications than the placebo group (P < 0.05). Proportion of patients with postoperative increase of creatinine level (20% and over) did not differ between placebo and drug groups.

CONCLUSION

Non-steroidal anti-inflammatory drugs may be used for analgesia management post CABG surgery in selected patients. Diclofenac appears to have the best analgesic effects by reducing the morphine and other analgesic requirement postoperatively.

The lack of benefit of tracheal extubation in the operating room after coronary artery bypass surgery

Although early tracheal extubation in cardiac anesthesia is safe and cost beneficial, questions still remain regarding how early after cardiac surgery patients should be tracheally extubated (TE). Our objective was to determine the effects on resource use if patients scheduled for coronary artery bypass grafting have TE in the operating room (OR). We studied 100 consecutive patients undergoing elective coronary artery bypass grafting, requiring extracorporeal circulation, and those eligible for a fast-track pathway. At the end of the procedure, the patients were evaluated for TE in the OR if they were hemodynamically stable, were without significant bleeding, and fulfilled clinical and blood gas analysis variables. Patients who did not meet the requirements had TE in the intensive care unit (ICU). Fifty patients had TE in the OR and 50 patients in the ICU. Time in the OR after skin closure, ICU length of stay, and postoperative length of stay were similar between the groups. Four patients (8%) in the OR group were tracheally reintubated secondary to respiratory depression (P = 0.11). Three patients (6%) in the OR group had postoperative myocardial infarction, and one postoperative myocardial infarction (2%) occurred in the ICU group (P = 0.61). All four patients recovered satisfactorily. The incidences of other complications were similar between groups.

Prophylactic nitroglycerin did not reduce myocardial ischemia during accelerated recovery management of coronary artery bypass graft surgery patients

OBJECTIVE

To evaluate the use of a high dose of nitroglycerin (NTG) for prophylaxis against myocardial ischemia and infarction in patients undergoing coronary artery bypass graft (CABG) surgery with accelerated recovery.

DESIGN

Prospective, double-blind, placebo-controlled randomized study.

SETTING

A university-based medical center.

PARTICIPANTS

Forty adult patients presenting for elective CABG surgery.

INTERVENTIONS

Forty patients were divided into 2 blinded study groups. Twenty patients received 2 microg/kg/min of NTG starting before induction of anesthesia and continuing for 6 hours after extubation in the intensive care unit. The placebo group (n = 20) received normal saline during this same interval.

MEASUREMENTS AND MAIN RESULTS

Hemodynamics, incidence and severity of myocardial ischemia, and myocardial infarction rates were determined. There were no differences in hemodynamic parameters between groups. The incidence of ischemia was approximately 35% in each group. Myocardial infarction (as determined by elevated creatine kinase-MB fraction, troponin I, and electrocardiogram criteria) was 10% in the placebo group and 5% in the NTG group (p = 0.234).

CONCLUSIONS

This study shows a high incidence of myocardial ischemia and infarction in patients presenting for CABG surgery with an accelerated recovery management scheme. NTG was well tolerated clinically; however, it was not found to be protective against myocardial ischemia or infarction in this setting.

Clinical outcomes and resource usage in 100 consecutive patients after off-pump coronary bypass procedures

BACKGROUND

Cardiopulmonary bypass initiates a cascade of inflammatory processes that may result in end-organ damage, leading to the increased prevalence of noncardiac complications. Therefore, off-pump coronary artery bypass graft (OP-CAB) procedures have recently been introduced into clinical practice.

METHODS

This study was a case-controlled study that compared the outcomes and cost of 100 consecutive OP-CAB procedures with a control group of 100 contemporary matched conventional coronary artery bypass grafting procedures. All operations were performed by a single surgeon (J.H.L. ) and complete revascularization that used off-pump techniques was achieved with the use of innovative exposure techniques to the lateral and posterior wall vessels.

RESULTS

An average of 3.1 grafts per patient were performed in the OP-CAB group (range, 1-5). The incidence of conversion to conventional coronary artery bypass grafting was 1%. The overall mortality rate was 2.0%. There were no instances of stroke, renal failure, or sternal infections in the OPCAB group. Thus, the OP-CAB group had a shorter length of stay (6.1+/-2.5 versus 7.1+/-3.3 d; P =.003), with a corresponding reduction in variable direct cost per case of 29% (P<.001).

CONCLUSION

Our experience suggests that OP-CAB procedures are feasible for most patients who currently require complete revascularization. It is associated with very a low morbidity rate and may represent the ideal revascularization strategy for patients at high risk for undergoing cardiopulmonary bypass.

Total intravenous anesthesia with a propofol-ketamine combination during coronary artery surgery

OBJECTIVE

To evaluate the cardiovascular effects of a propofol-ketamine combination in patients undergoing coronary artery surgery.

DESIGN

Prospective, randomized study.

SETTING

Tertiary care teaching hospital, single center.

PARTICIPANTS

Seventy-eight adult patients.

INTERVENTIONS

Patients were randomly allocated to receive propofol-ketamine for induction and maintenance of anesthesia (n = 36) or fentanyl-enflurane (controls, n = 42).

MEASUREMENTS AND MAIN RESULTS

Hemodynamics and other variables were recorded during and after surgery and for 24 hours in the intensive care unit. Before cardiopulmonary bypass (CPB), there was similar incidence of treatment for hypotension (42% of patients in both groups), tachycardia (propofol-ketamine, 6%; controls, 5%), and myocardial ischemia (propofol-ketamine, 3%; controls, 12%). In the propofol-ketamine group, there was a decreased requirement for inotropic agents after CPB (22% of patients) compared with controls (49% of patients; p = 0.02). There was a reduced incidence of myocardial infarctions (creatine kinase myocardial band >133 U/L) in the propofol-ketamine group compared with the control group (0% v 14%; p = 0.02; Fisher's exact test). Patients in the propofol-ketamine group were more likely to have their tracheas extubated within 8 hours of arrival in the intensive care unit compared with controls (33% v 7%; p = 0.01; Cochran-Mantel-Haenzel test).

CONCLUSIONS

The propofol-ketamine combination was associated with a similar incidence of pre-CPB hypotension and ischemia, a decreased need for inotropes after CPB, an earlier time to tracheal extubation, and a reduced incidence of myocardial infarctions compared with controls.

Predictive accuracy study: comparing a statistical model to clinicians' estimates of outcomes after coronary bypass surgery

BACKGROUND

The purpose of this study was to compare clinicians' prior probability estimates of operative mortality (OM) and prolonged intensive care unit stay (ICU) length of stay greater than 48 hours after coronary artery bypass graft surgery (CABG) with estimates derived from statistical models alone.

METHODS

Nine clinicians estimated the predicted probability of OM and ICU stay greater than 48 hours from an abstract of information for each of 100 patients selected from the 1996 to 1997 database of 1,904 patients who underwent isolated CABG. Logistic regression models were used to calculate the predicted probability of OM and ICU stay greater than 48 hours for each patient. The study sample was split into two parts; clinicians were randomly given access to a predictive rule to guide their judgements for one part of the study.

RESULTS

Clinicians' estimates were similar with or without access to the rule, and both parts of the study were therefore pooled. Clinicians significantly overestimated the probability of OM (model 6.3% +/- 1%, clinicians 7.6% +/- 3%, p = 0.0001) and ICU stay greater than 48 hours (model 25% +/- 2%, clinicians 28% +/- 1%, p = 0.0012). Clinicians' estimates of OM were not significantly higher than the model's for nonsurvivors (0.8% +/- 0.7%, p = 0.2), but were significantly higher for survivors (1.4% +/- 0.3%, p = 0.039).

CONCLUSIONS

Clinicians trusted their own empiric estimates rather than a predictive rule and overestimated the probability of OM and ICU stay greater than 48 hours.

Optimizing timing of early extubation in coronary artery bypass surgery patients

BACKGROUND

This study was designed to assess the safety and efficacy of extubation performed within 4 hours of the patient's arrival in the surgical intensive care unit after coronary artery bypass graft surgery.

METHODS

A matched retrospective cohort study was performed including 412 consecutive patients undergoing isolated coronary artery bypass graft surgery between January 1996 and December 1997, constituting the experience of a single surgeon (J.H.L.). Early extubation (defined as extubation within 8 hours of arrival at the surgical intensive care unit) was achieved in 308 of 412 patients (75%). Patients extubated in fewer than 4 hours after arrival (n = 200) were compared with patients extubated within 4 to 8 hours (n = 108).

RESULTS

Four deaths occurred in 412 patients, for an overall operative mortality rate of 1.0%. Patients extubated in fewer than 4 hours were younger than those extubated 4 or more hours after admission (62 versus 67 years old, respectively; p = 0.001), more likely to be male (74% versus 63%, p < 0.05), and had shorter aortic cross-clamp times (49.4 +/- 15.0 versus 53.5 +/- 14.0 minutes, p < 0.05) and cardiopulmonary bypass (CPB) times (65.2 +/- 18.6 versus 72.1 +/- 19.1 minutes, p < 0.05) compared to patients extubated later. Moreover, patients extubated in fewer than 4 hours had a shorter surgical intensive care unit length of stay (33.8 +/- 25.7 versus 43.1 +/- 43.0 hours, p < 0.05) and shorter postoperative length of stay (5.4 +/- 2.4 versus 6.2 +/- 2.6 days, p = 0.01) than those extubated later.

CONCLUSIONS

Extubation in fewer than 4 hours may offer a substantial advantage in terms of accelerated recovery compared with extubation within 4 to 8 hours. Very few differences in clinical parameters were noted between the two groups we studied, suggesting that efforts to reduce extubation times further might be worthwhile.

Insulin cardioplegia for elective coronary bypass surgery

BACKGROUND

Improved methods of myocardial preservation are required to reduce the morbidity and mortality of coronary bypass surgery for high-risk subgroups. Metabolic stimulation with insulin, glucose solutions, or both has been proposed as a method to preserve the ischemic myocardium. We performed a prospective, double-blind, randomized trial to evaluate the effects of insulin and glucose as cardioplegic additives when used as part of a tepid continuous blood cardioplegic strategy.

METHODS

We randomized 56 male patients undergoing elective isolated coronary bypass surgery to 1 of 4 cardioplegic groups containing either 42 or 84 mmol/L glucose with or without 10 IU/L of insulin. Perioperative assessments of myocardial metabolism and left ventricular function were performed.

RESULTS

Insulin-enhanced cardioplegia was associated with beneficial effects on both myocardial metabolic and functional recovery after cardioplegic arrest. Insulin's effect was independent of the ambient glucose concentration.

CONCLUSIONS

Cardioplegic formulations containing a 42 mmol/L concentration of glucose and a 10 IU/L concentration of insulin provide significant benefit to patients undergoing isolated coronary bypass surgery. The clinical effect of these formulations will need to be assessed in high-risk subgroups of patients, such as those with unstable angina, recent myocardial infarction, or poor left ventricular function.

Continuous infusion of remifentanil and target-controlled infusion of propofol for patients undergoing cardiac surgery: a new approach for scheduled early extubation

OBJECTIVE

To assess hemodynamic stability, postoperative pain management, and the control and timing of early extubation of a total intravenous anesthetic technique using propofol target-controlled infusion (TCI) and remifentanil in cardiac surgery.

DESIGN

Prospective study.

SETTING

University hospital.

PARTICIPANTS

Fifty patients scheduled for elective cardiac surgery.

INTERVENTIONS

Premedication consisted of oral midazolam, 0.1 mg/kg. Anesthesia was induced with propofol TCI at a target concentration of 1.5 to 2 microg/mL; remifentanil, 1 microg/kg; and rocuronium. Anesthesia was maintained with propofol at the same target concentration and remifentanil titrated between 0.25 and 1 microg/kg/min. Thirty minutes before the end of surgery, a 0.1-mg/kg bolus of morphine was administered intravenously. Postoperative sedation was achieved by maintaining the propofol infusion until the patient was deemed ready for extubation. Postoperative pain relief was evaluated using a visual analog scale. The intervals between arrival in the intensive care unit, spontaneous ventilation, and extubation were recorded.

MEASUREMENTS AND MAIN RESULTS

Included in this study were 36 men and 14 women (American Society of Anesthesiologist = III; New York Heart Association = II) scheduled for cardiac surgery. All patients remained hemodynamically stable throughout the perioperative period. Thirty-seven patients were successfully extubated during the first 4 postoperative hours. Spontaneous breathing was achieved at a mean interval of 15+/-5 minutes after propofol discontinuation. The mean interval to extubation was 163+/-45 minutes after arrival in the intensive care unit. Extubation was performed 48+/-12 minutes after patients were considered ready to awaken. During spontaneous ventilation, 36 patients received additional boluses of morphine (mean, 2.5+/-1 mg). Subsequently, all patients achieved a visual analog scale less than 40 mm.

CONCLUSION

The combination of remifentanil and propofol TCI resulted in hemodynamic stability and good postoperative analgesia. This technique allows physicians to schedule the time of extubation in patients undergoing cardiac anesthesia.

Effect of a nursing-implemented sedation protocol on the duration of mechanical ventilation

OBJECTIVE

To compare a practice of protocol-directed sedation during mechanical ventilation implemented by nurses with traditional non-protocol-directed sedation administration.

DESIGN

Randomized, controlled clinical trial.

SETTING

Medical intensive care unit (19 beds) in an urban teaching hospital.

PATIENTS

Patients requiring mechanical ventilation (n = 321).

INTERVENTIONS

Patients were randomly assigned to receive either protocol-directed sedation (n = 162) or non-protocol-directed sedation (n = 159).

MEASUREMENTS AND MAIN RESULTS

The median duration of mechanical ventilation was 55.9 hrs (95% confidence interval, 41.0-90.0 hrs) for patients managed with protocol-directed sedation and 117.0 hrs (95% confidence interval, 96.0-155.6 hrs) for patients receiving non-protocol-directed sedation. Kaplan-Meier analysis demonstrated that patients in the protocol-directed sedation group had statistically shorter durations of mechanical ventilation than patients in the non-protocol-directed sedation group (chi-square = 7.00, p = .008, log rank test; chi-square = 8.54, p = .004, Wilcoxon's test; chi-square = 9.18, p = .003, -2 log test). Lengths of stay in the intensive care unit (5.7+/-5.9 days vs. 7.5+/-6.5 days; p = .013) and hospital (14.0+/-17.3 days vs. 19.9+/-24.2 days; p < .001) were also significantly shorter among patients in the protocol-directed sedation group. Among the 132 patients (41.1%) receiving continuous intravenous sedation, those in the protocol-directed sedation group (n = 66) had a significantly shorter duration of continuous intravenous sedation than those in the non-protocol-directed sedation group (n = 66) (3.5+/-4.0 days vs. 5.6+/-6.4 days; p = .003). Patients in the protocol-directed sedation group also had a significantly lower tracheostomy rate compared with patients in the non-protocol-directed sedation group (10 of 162 patients [6.2%] vs. 21 of 159 patients [13.2%], p = .038).

CONCLUSIONS

The use of protocol-directed sedation can reduce the duration of mechanical ventilation, the intensive care unit and hospital lengths of stay, and the need for tracheostomy among critically ill patients with acute respiratory failure.

The Economics of Cardiac Fast Tracking

Extubation within a few hours of cardiac surgery is possible in the majority of patients and is not associated with an increased risk for perioperative complications. Duration of intubation is an important factor in overall postoperative length of stay, and when early extubation is instituted as part of a comprehensive clinical pathway, it contributes to significant reductions in both intensive care unit and hospital length of stay. In association with reductions in direct variable costs, these reductions in length of stay have been shown in several studies to significantly reduce overall cost or charge.

Intrathecal morphine for coronary artery bypass graft procedure and early extubation revisited

OBJECTIVE

To determine the dose of intrathecal (IT) morphine (along with the intraoperative baseline anesthetic) that provides significant analgesia yet does not delay extubation in the immediate postoperative period in patients undergoing cardiac surgery and early extubation.

DESIGN

Prospective, randomized, double-blinded, placebo-controlled clinical study.

SETTING

Single university hospital.

PARTICIPANTS

Forty patients undergoing elective coronary artery bypass graft procedure and early extubation.

INTERVENTIONS

Twenty patients received 10 microg/kg of IT morphine, and 20 patients received IT placebo. Perioperative anesthetic management was standardized and included postoperative patient-controlled morphine analgesia.

MAIN RESULTS

Of the patients tracheally extubated during the immediate postoperative period, mean time to extubation was similar in patients who received IT morphine (6.8+/-2.8 h) or IT placebo (6.5+/-3.2 h). Four patients who received IT morphine had extubation substantially delayed because of prolonged ventilatory depression. There was no difference between groups in postoperative patient-controlled morphine analgesia use.

CONCLUSION

Even when used in conjunction with an intraoperative baseline anesthetic that allows early extubation, IT morphine (10 microg/kg) was unable to provide substantial postoperative analgesia. The risks of using IT morphine in patients undergoing cardiac surgery and early extubation may outweigh the potential benefits.

Structural models for intermediate care areas

OBJECTIVE

To describe structural models of intermediate care units used for critically ill patients.

DATA SOURCES

Three multidisciplinary units with varying structures and functions of intermediate care areas (ICAs) are described.

DATA SYNTHESIS

Advantages and limitations for each of the three models are outlined. The structural models described are the conventional isolated ICA model, the parallel model, and the integrated model of ICA.

CONCLUSION

Each structural model has advantages and limitations. Selection of the appropriate ICA model for an institution depends on the specific circumstances and needs of the institution. Each of the three models can facilitate improved utilization of critical care resources.

Fast-track cardiac anesthesia in patients with sickle cell abnormalities

We conducted a retrospective review of 10 patients with sickle cell trait (SCT) and 30 patients (cohort control) without SCT undergoing first-time coronary artery bypass graft surgery with cardiopulmonary bypass. Demographic, perioperative management, and outcome data were collected. Both groups were matched according to age, weight, duration of surgery, and preoperative hemoglobin (Hb) concentration. Distribution of gender, medical conditions, pharmacological treatment, and preoperative left ventricular function were similar between the groups. The comparisons were analyzed in respect to postoperative blood loss and transfusion rates, as well as duration of intubation, intensive care unit, and hospital length of stay (LOS). All patients underwent fast-track cardiac anesthesia. A combination of cold crystalloid and blood cardioplegia was used. The lowest nasopharyngeal temperature was 33 degrees C. There were no episodes of significant hypoxemia, hypercarbia, or acidosis. None of the patients had sickling crisis during the perioperative period. The postoperative blood loss was 687 +/- 135 vs 585 +/-220 mL in the SCT and control groups, respectively. The trigger for blood transfusion during cardiopulmonary bypass was hematocrit <20% and Hb <75 g/L postoperatively. Three SCT patients (30%) and 10 control patients (33%) received a blood transfusion. Median extubation time was 4.0 vs 3.9 h; intensive care unit LOS was 27 vs 28 h; and hospital LOS was 6.0 vs 5.5 days in the SCT and control groups, respectively. There were no intraoperative deaths. One patient in the SCT group died from multiorgan failure 2 mo after surgery.

IMPLICATIONS

Fast-track cardiac anesthesia can be used safely in patients with sickle cell trait undergoing first-time coronary artery bypass graft surgery. Extubation time and intensive care unit and hospital length of stay are comparable to those of matched controls, and blood loss and transfusion requirements are not increased. A hematocrit of 20% seems to be a safe transfusion trigger during cardiopulmonary bypass in these patients.

Influence of fast-track anesthetic technique on cardiovascular infusions and weight gain

OBJECTIVE

To evaluate whether cardiac surgical patients receiving conventional versus fast-track anesthetic management are statistically significantly different with regard to cardiovascular drug infusions, weight gain, cardiac and pulmonary morbidity, length of intubation, and length of stay.

DESIGN

Retrospective, (partially) sequential, cohort design.

SETTING

Surgical suite and intensive care unit (ICU) at a community hospital.

PARTICIPANTS

Two hundred seven patients who presented for coronary artery bypass graft and/or cardiac valve replacement.

INTERVENTIONS

None

MEASUREMENTS AND MAIN RESULTS

Group comparisons of the seven individual cardiovascular drug infusions showed less frequent use in the fast-track patients for lidocaine (9% v 28%; p = 0.00046) only. However, the fast-track group received fewer combinations of cardiovascular drug infusions overall for the first 24-hour postoperative period (p < 0.0005). Hourly comparisons of inotropes showed significantly fewer combinations of dobutamine, norepinephrine, and epinephrine for the first postoperative hour and for postoperative hours 7 through 12 (p < 0.01 for each hour). Fast-track patients had less postoperative weight gain for days 1 through 4 (p < 0.01 for each day), shorter length of ICU stay (p < 0.00005), and shorter total length of postoperative hospital stay (p = 0.0004). No differences were found with respect to myocardial infarction, death, pulmonary complications, rate of reintubation, or length of hospital stay once discharged from the ICU.

CONCLUSIONS

Fast-track anesthetic management may be associated with decreased need for inotropic and antiarrhythmic drug infusions and decreased weight gain.

[Minimally invasive cardiac surgery: surgical techniques and anesthetic problems]

OBJECTIVE

To review current data on minimally invasive cardiac surgery.

DATA SOURCES

Search through the Medline data base of French or English articles.

DATA EXTRACTION

The articles were analysed to make a synthesis of the various techniques with their main indications and contra-indications.

DATA SYNTHESIS

Minimally invasive cardiac surgery includes various surgical procedures. The usual techniques are described, their major benefits and drawbacks are discussed. The main goals of anaesthetic management are preservation of ventricular function and systemic perfusion, detection and treatment of myocardial ischaemia, prevention of hypothermia in case of coronary artery bypass grafting on the beating heart via sternotomy, intermittent selective ventilation of the collapsed lung using CPAP in case of limited thoracotomy. Expertise in transoesophageal echocardiography is essential for insertion and checking the accurate positioning of the various catheters of the endovascular CPB Heartport system (pulmonary vent, endosinus catheter, venous cannula, endoaortic clamp) allowing coronary artery bypass grafting and mitral valve surgery through limited thoracotomy and finally, detection of retained intracardiac air and assessment of complete clearing of cardiac cavities after mitral valve surgery through limited thoracotomy and aortic valve surgery via ministernotomy. Short-acting anaesthetic agents allow rapid recovery from anaesthesia, early extubation and discharge to the surgical ward within 24 h, whereas overall time spent in the operating room is often longer than with conventional cardiac surgery.

Fast track recovery of elderly coronary bypass surgery patients

BACKGROUND

To ascertain whether early extubation and fast-track treatment protocols are feasible in elderly patients, we analyzed 487 consecutive patients who had isolated coronary artery bypass grafting between January 1995 and June 1997, constituting the experience of a single surgeon.

METHODS

Management consistently applied to all patients emphasized early extubation protocol, tepid cardioplegia and normothermic bypass to reduce pump times, early mobilization and chest tube removal, and protocol treatment of atrial fibrillation. Elderly patients at least 70 years old (n = 176, mean age 75 years) were compared with younger patients (n = 311, mean age 58 years).

RESULTS

The hospital mortality rate was 0.8% (4 of 487 patients), and there was no difference in the operative mortality rate of the older cohort versus the younger cohort (0.6% versus 0.9%; p > 0.05). Older patients had a higher incidence of peripheral vascular disease, congestive heart failure, prior strokes, renal failure, and cerebrovascular disease (p < 0.05). Early extubation was achieved in 71% of younger patients versus 57% of older cohort (95% confidence interval, 14%+/-9%; p = 0.002). Older patients had significantly higher incidence of postoperative atrial fibrillation (27% versus 14%; 95% CI, 13%+/-7%; p < 0.001), a factor responsible for shorter length of stay among younger patients (5.6+/-2.8 days versus 7.2+/-3.7 days; 95% CI, 1.6+/-0.3 days; p < 0.001). Nonetheless discharge before the fifth postoperative day was achieved in 34% of the elderly patients.

CONCLUSIONS

Although elderly patients have a higher acuity of illness, critical pathways for accelerated discharge are safe and feasible in most elderly patients.

Who goes to the ICU postoperatively?

OBJECTIVE

To describe changes in ICU postoperative management strategies utilized for patients undergoing cardiac surgery. The treatment of these patients serves as a useful illustration of the changing patterns of ICU utilization and care associated with contemporary surgery.

DESIGN

Evidence-based review of the clinical literature following a MEDLINE search, direct observation of rapid recovery programs following surgery, and informal inquiry of others utilizing similar approaches to postoperative cardiac surgery care.

SETTING AND PATIENTS

The reports reviewed are from a diverse set of hospitals providing cardiac surgery services in both Europe and the United States. Most reports focus efforts on patients undergoing coronary artery revascularization.

MEASUREMENTS

Outcome measures used to gauge the effectiveness of postoperative ICU care typically include time to extubation, ICU and hospital length of stay, postoperative complications including reintubation and ICU readmission, patient satisfaction, and health resource savings.

MAIN RESULTS

The literature regarding current practice for postoperative ICU management in cardiac surgery consists primarily of grade 2 and 3 literature.

CONCLUSIONS

Despite the paucity of controlled data, rapid recovery, extubation, and discharge from the ICU following cardiac surgery is an approach to care that is growing in acceptance. The goals include reduction in the utilization of resources and costs associated with cardiac surgery and maintenance of quality of care and patient satisfaction. Assessment of outcomes requires a program to monitor outcomes. Success does not appear to be linked to preoperative risk for most patients but does relate directly to the anesthetic management delivered in the operating room. Few adverse consequences from this approach have been reported. Experience to date suggests that programs designed to truncate ICU admission following cardiac surgery can be implemented with the cooperation between the health delivery team including surgeon, anesthesiologist, intensivist where available, nursing, respiratory care, and patient and family. These programs can serve as useful models for reassessing the utilization and role of the ICU in the postoperative treatment of routine surgical patients.

Effect of low-dose propofol infusion on total-body oxygen consumption after coronary artery surgery

OBJECTIVE

To investigate the effect of low-dose propofol infusion on total-body oxygen consumption (VO2) after coronary artery bypass grafting (CABG) surgery.

DESIGN

A prospective, randomized, placebo-controlled, double-blind study.

SETTING

Cardiovascular intensive care unit in a university hospital.

PARTICIPANTS

Thirty patients after elective, uncomplicated CABG surgery.

INTERVENTION

Patients were administered a continuous infusion of propofol with a fixed rate of 1 mg/kg/h (n = 15) or placebo (n = 15) during the spontaneous rewarming period of approximately 5 hours after surgery. A light level of sedation (Ramsay sedation score > or =2) was maintained by administering small doses of diazepam, 0.1 mg/kg, as required. Morphine, 0.05 mg/kg, was administered for analgesia as required.

MEASUREMENTS AND MAIN RESULTS

Total-body VO2 was measured by indirect calorimetry. In addition, shivering (on a five-grade scale), hemodynamics, and plasma catecholamine and serum cortisol concentrations were measured. Diazepam, 5.6+/-7.4 mg (mean +/- standard deviation), was administered to the patients receiving propofol, and 16.1+/-12.2 mg was administered to the patients receiving placebo (p < 0.05). There was no difference in the dose of morphine between the groups (3.2+/-3.9 v 4.2+/-5.5 mg in the propofol and placebo groups, respectively). At any time during the study, VO2 was not different between the groups. VO2 increased from 130+/-29 to 172+/-29 mL/min/m2 in the propofol group and from 118+/-24 to 167+/-27 mL/min/m2 in the placebo group. Mean arterial pressure and heart rate were lower in the propofol group (p < 0.05). Stress hormone levels did not differ between the groups.

CONCLUSION

Low-dose propofol infusion and additional diazepam as required does not decrease total-body VO2 compared with a pure diazepam bolus-dose technique when administered for light sedation during the immediate recovery period after CABG surgery.

Early versus late extubation after coronary artery bypass grafting: effects on cognitive function

OBJECTIVE

To compare the effects of a short period of mechanical ventilation and sedation and a longer one on cognitive functioning of patients exposed to cardiopulmonary bypass (CPB).

DESIGN

A randomized, prospective study.

SETTING

Tertiary-care university hospital.

PARTICIPANTS

Forty-eight adult patients with surgical coronary artery disease.

INTERVENTION

Elective coronary artery bypass surgery.

MEASUREMENT AND MAIN RESULTS

Patients (n = 48; mean age, 60.12+/-9.30 years) were randomized to either group I (mean delay, 3.49+/-2.21 hours) or group II (mean delay, 10.32+/-1.75 hours). Cognitive functioning was evaluated before surgery, postoperatively, and at the 8-week follow-up. Tests included measures of central nervous system integrity, attention/concentration and psychomotor performance, verbal fluency, visual scanning speed, mental flexibility, auditory and visual attention, and verbal memory. Covariance analyses were used for group comparisons. Covariates were age, education, and baseline or postoperative performance. No differences in cognitive functioning were found between the two groups. Globally, performance deteriorated for 34.1% of the patients at the posttest evaluation, whereas 2.3% improved and 63.6% remained unchanged. At follow-up, nearly 40.5% of the patients showed an improvement from baseline, 2.4% still had deficits, and 57.1% had no change. None of the cognitive functions appeared to be more affected than others.

CONCLUSION

Early extubation and a shortened period of anesthesia/analgesia do not appear to positively or negatively affect cognitive functioning at 3 to 5 days and 8 weeks postoperatively. Early extubation is suggested because it has no deleterious effect (besides the low risk for reintubation) and it may facilitate patients' care in the intensive care unit.

Perioperative predictors of extubation failure and the effect on clinical outcome after cardiac surgery

OBJECTIVES

To determine perioperative predictors of extubation failure (requirement for reintubation and mechanical ventilation after prior successful weaning from ventilator support and extubation) after cardiac surgery and the effect on clinical outcome.

DESIGN

Cohort study.

SETTING

A tertiary-care, 54-bed, cardiothoracic intensive care unit (ICU).

PATIENTS

ICU admissions (n = 11,330) after cardiac surgery over a 42-month period.

INTERVENTIONS

Collection of preoperative, operative, and ICU data from a database.

MEASUREMENTS AND MAIN RESULTS

Frequency of extubation failure, total duration of mechanical ventilation, length of stay in ICU and hospital, and death. There were 748 (6.6%) patients who were weaned from mechanical ventilation after cardiac surgery and required reintubation and ventilator support. The predictors of extubation failure were: age of > or =65 yrs; inpatient hospitalization before surgery; arterial vascular disease; chronic obstructive pulmonary disease; pulmonary hypertension; severe left ventricular dysfunction; cardiac shock; hematocrit of < or =34%; blood urea nitrogen of > or =24 mg/dL; serum albumin concentration of < or =4.0 g/dL (< or =40.0 g/ L); systemic oxygen delivery of < or =320 mL/min/m2; redo operation; surgical procedures involving the thoracic aorta; transfusion of blood products of > or =10 units; and cardiopulmonary bypass time of > or =120 mins. Extubation failure prolonged the length of total mechanical ventilation, as well as ICU and hospital stay, independent of the frequency of organ dysfunction or nosocomial infections but did not increase the risk of death after cardiac surgery.

CONCLUSIONS

Extubation failure after cardiac surgery is uncommon. Although extubation failure increased the utilization of ICU and hospital resources, it did not affect mortality after cardiac surgery. Protocols for early extubation and ICU discharge should be modified in the presence of certain preoperative and operative predictors of extubation failure to avoid unnecessary increase in the cost of care after cardiac surgery.

Morbidity outcome in patients with hypertrophic obstructive cardiomyopathy undergoing cardiac septal myectomy: early-extubation anesthesia versus high-dose opioid anesthesia technique

OBJECTIVE

Anesthetic management of patients with hypertrophic obstructive cardiomyopathy (HOCM) undergoing septal myectomy is challenging. The morbidity outcome of early-extubation anesthesia (EEA), or fast tracking, versus high-dose opioid (HDO) anesthesia was studied.

DESIGN

Retrospective study.

SETTING

University teaching hospital.

PARTICIPANTS

One hundred seventy-five cardiac septal myectomy patients (EEA, n = 53; HDO, n = 122).

INTERVENTIONS

EEA technique consisted of low-dose fentanyl, 10 to 15 microg/kg; propofol infusion; midazolam; and inhalation agent. HDO technique consisted of fentanyl, 50 to 100 microg/kg, and benzodiazepines, with or without an inhalation agent. Demographic data, preoperative symptoms, and data on anesthesia management and postoperative complications were recorded.

MEASUREMENTS AND MAIN RESULTS

There were no differences between the groups (EEA v HDO, respectively) regarding age, sex, preoperative symptoms (dyspnea, 89% v 79%; palpitations, 28% v 26%; angina, 47% v 61%; syncope, 47% v 41%), redo surgery, or combined surgery. Mean +/- standard deviation time to tracheal extubation was 7.2 +/- 5.3 hours in EEA versus 19.4 +/- 10.5 hours in HDO patients (p < 0.0001). Intensive care unit (ICU) stay was significantly shorter in EEA versus HDO patients (2.2 v 3.0 days; p < 0.005), with the trend toward earlier hospital discharge (9.7 v 11.3 days; p = 0.09). There was a high requirement for temporary pacing in both groups immediately postoperatively (EEA, 60% v HDO, 48%; p > 0.08). Permanent pacemaker insertion postoperatively was required in 7 of 53 patients (13%) in the EEA group and 11 of 122 patients (9%) in the HDO group (p > 0.25). Atrial arrhythmias occurred postoperatively in 25% of EEA patients versus 34% of HDO patients (p > 0.08).

CONCLUSION

EEA facilitates earlier tracheal extubation by 12 hours in patients with HOCM undergoing septal myectomy, significantly shortening ICU stay by 1 day without increasing perioperative cardiac morbidity or mortality.

An institution's initial experience with port-access minimally invasive cardiac surgery

OBJECTIVE

To assess the learning curve associated with Port-Access minimally invasive cardiac surgery.

DESIGN

Retrospective.

SETTING

Single university hospital.

PARTICIPANTS

Initial 10 patients undergoing Port-Access minimally Invasive cardiac surgery.

INTERVENTION

Minimally invasive cardiac surgery.

MEASUREMENTS AND MAIN RESULTS

All 10 patients experienced an uneventful intraoperative and immediate postoperative course. Only one patient experienced postoperative cardiovascular morbidity, which was an episode of new-onset atrial fibrillation after mitral valve surgery that was successfully treated with pharmacologic therapy. Extubation times and postoperative discharge times were less than historic controls receiving the same anesthetic technique at the same institution.

CONCLUSION

This institution's initial experience with 10 patients undergoing Port-Access minimally invasive cardiac surgery suggests an acceptable learning curve and decreased extubation and postoperative discharge times, which should translate into reduced health care costs.

Computer simulation of changes in nursing productivity from early tracheal extubation of coronary artery bypass graft patients

STUDY OBJECTIVE

To determine whether the results from a clinical trial, which showed that early extubation of elective coronary artery bypass graft (CABG) patients can reduce hospital costs by more rapid discharge of patients from the intensive care unit (ICU), are likely to apply to other hospitals.

DESIGN

Discrete-event computer simulation.

MEASUREMENTS AND MAIN RESULTS

We (1) generated simulated CABG patients, (2) had them "flow" from one condition to the next according to specified rules, and (3) calculated the labor productivity of simulated nurses who would be caring for the patients. We defined nursing labor productivity as the number of patients undergoing elective CABG cared for each year per nursing full-time equivalent working 40 hours per week. Our simulations predict that the increase in nursing labor productivity achieved by early extubation of CABG patients is sensitive to the number of elective CABG cases performed each year at the hospital and the method of compensating nurses. Hospitals with an "hourly workforce" and many cases per year are predicted to achieve a greater increase in productivity from early extubation than are hospitals with a "salaried workforce" and less active volume. At hospitals with a salaried workforce, increasing the percentage of patients extubated early may have no effect on labor productivity.

CONCLUSIONS

Although "fast-tracking" protocols may offer benefits other than increasing nursing labor productivity (i.e., saving money), the results of clinical trials that demonstrate cost savings from clinical pathways that include early tracheal extubation are likely to apply only to hospitals that have similar annual CABG volume and method of compensating nurses as those in the clinical trial. To estimate the likely economic impact from early extubation protocols, a hospital should complete a simulation study with parameter values appropriate to its institution.

Circulatory arrest under moderate systemic hypothermia and cold retrograde cerebral perfusion

BACKGROUND

Profound hypothermia is used for circulatory arrest during cardiovascular operations. Cold retrograde cerebral perfusion enhances cerebral protection during circulatory arrest. This study examines the results of circulatory arrest under moderate systemic hypothermia and cold retrograde cerebral perfusion.

METHODS

Circulatory arrest under moderate systemic hypothermia (nasopharyngeal temperatures of 19 degrees to 28 degrees C, mean of 23 degrees C) and cold (10 degrees C) retrograde cerebral perfusion were employed in 104 consecutive patients for operation on the proximal aorta (103 patients) or for a venous tumor invading the heart (1 patient). Aortic operations consisted of replacement of the entire transverse arch in 49 patients, hemiarch in 16, ascending aorta in 37, and an extraanatomic aortic bypass in 1. Most patients (83%) also had other procedures such as coronary artery bypass or an aortic valve operation. Sixteen patients had had previous aortic operations. The mean circulatory arrest time was 27 minutes (range, 6 to 105 minutes).

RESULTS

There were eight in-hospital deaths. Preoperative shock, peripheral vascular disease, and previous aortic operations were independent predictors of operative mortality. There were eight strokes; clinical assessment and computed tomographic scans of the brain suggested that the strokes were embolic in 6 patients. Atherosclerosis/laminated thrombi in the aorta and the duration of circulatory arrest were independent predictors of stroke. Four patients had seizures without neurologic deficit. No patient had development of paraplegia or paraparesis.

CONCLUSIONS

Systemic hypothermia of 23 degrees C (nasopharyngeal) and cold retrograde cerebral perfusion (10 degrees C) appear to be safe for circulatory arrest times of less than 30 minutes. This strategy of cerebral protection may also be adequate for longer circulatory arrest times.

Change in anaesthesia practice and postoperative sedation shortens ICU and hospital length of stay following coronary artery bypass surgery

We randomized prospectively 144 patients, undergoing elective coronary artery bypass surgery, to either early or to routine extubation [mechanical ventilatory support for 4-7 h (Group A), or 8-14 h (Group B)]. Anaesthesia was modified for both groups. The groups were well matched in terms of sex, age, NYHA class, preoperative left ventricular ejection fraction, bypass time and aortic cross-clamp time, number of grafts used, and blood units transfused. All patients had normal preoperative respiratory, renal, hepatic and cerebral functions. Mechanical ventilatory support (mean +/- SD) was 6.3 +/- 0.7 h for Group A and 11.6 +/- 1.3 h for Group B. Mean ICU stay was 17 +/- 1.3 h for Group A and 22 +/- 1.2 h for Group B, while the mean hospital stay was 7.3 +/- 0.8 days and 8.4 +/- 0.9, respectively. There were no statistically significant differences in the frequency of all postoperative complications among the two groups. There were no reintubation, readmission to the ICU or death in either group. We concluded that change in anaesthesia practice and early postoperative sedation in patients undergoing elective coronary artery bypass graft (CABG) surgery resulted in earlier tracheal extubation, shorter ICU and hospital length of stay without organ dysfunction or postoperative complications. Early extubation was only possible due to the modification of anaesthesia and ICU sedation regime.

The use of continuous i.v. sedation is associated with prolongation of mechanical ventilation

STUDY OBJECTIVE

To determine whether the use of continuous i.v. sedation is associated with prolongation of the duration of mechanical ventilation.

DESIGN

Prospective observational cohort study.

SETTING

The medical ICU of Barnes-Jewish Hospital, a university-affiliated urban teaching hospital.

PATIENTS

Two hundred forty-two consecutive ICU patients requiring mechanical ventilation.

INTERVENTIONS

Patient surveillance and data collection.

MEASUREMENTS AND RESULTS

The primary outcome measure was the duration of mechanical ventilation. Secondary outcome measures included ICU and hospital lengths of stay, hospital mortality, and acquired organ system derangements. A total of 93 (38.4%) mechanically ventilated patients received continuous i.v. sedation while 149 (61.6%) patients received either bolus administration of i.v. sedation (n=64) or no i.v. sedation (n=85) following intubation. The duration of mechanical ventilation was significantly longer for patients receiving continuous i.v. sedation compared with patients not receiving continuous i.v. sedation (185+/-190 h vs 55.6+/-75.6 h; p<0.001). Similarly, the lengths of intensive care (13.5+/-33.7 days vs 4.8+/-4.1 days; p<0.001) and hospitalization (21.0+/-25.1 days vs 12.8+/-14.1 days; p<0.001) were statistically longer among patients receiving continuous i.v. sedation. Multiple linear regression analysis, adjusting for age, gender, severity of illness, mortality, indication for mechanical ventilation, use of chemical paralysis, presence of a tracheostomy, and the number of acquired organ system derangements, found the adjusted duration of mechanical ventilation to be significantly longer for patients receiving continuous i.v. sedation compared with patients who did not receive continuous i.v. sedation (148 h [95% confidence interval: 121, 175 h] vs 78.7 h [95% confidence interval: 68.9, 88.6 h]; p<0.001).

CONCLUSION

We conclude from these preliminary observational data that the use of continuous i.v. sedation may be associated with the prolongation of mechanical ventilation. This study suggests that strategies targeted at reducing the use of continuous i.v. sedation could shorten the duration of mechanical ventilation for some patients. Prospective randomized clinical trials, using well-designed sedation guidelines and protocols, are required to determine whether patient-specific outcomes (eg, duration of mechanical ventilation, patient comfort) can be improved compared with conventional sedation practices.

A comparison of clonidine with conventional preanesthetic medication in patients undergoing coronary artery bypass grafting

In this controlled study, we compared clonidine with conventional premedication in 35 patients undergoing coronary artery bypass grafting (CABG). After premedication with clonidine 5 microg/kg p.o. (Group C, n = 11), lorazepam 60 microg/kg p.o. (Group L, n = 13), or morphine 0.1 mg/kg plus scopolamine 6 microg/kg i.m. (Group M, n = 11), sedation, anxiety, and quality of premedication were graded. After the administration of sufentanil 2.0 microg/kg over 12.5 min, a computer-assisted infusion device targeted a sufentanil effect-site concentration of 0.75 ng/mL. Hemodynamic variables, end-tidal isoflurane concentration (ET-ISO), the electroencephalographic spectral edge, and the serum sufentanil concentration (SUF) were measured. There were no intergroup differences in anxiety, sedation, quality of premedication, the dose of sufentanil causing unconsciousness, or the electroencephalographic (EEG) response to induction. Intraoperative SUF was stable, with no intergroup difference. The average prebypass ET-ISO was lower in Group C than in Group M. The ET-ISO and peak ET-ISO after intense surgical stimulation were lower in Group C versus Groups L and M. Mean arterial blood pressure was lower in Group C versus Groups L and M. There were no intergroup differences in pharmacologic intervention, time to extubation, or intensive care unit stay. Clonidine produces sedation, anxiolysis, and quality of premedication comparable to conventional premedication. Compared with other drugs, clonidine does not alter the dose of sufentanil inducing unconsciousness or EEG slowing, but it uniquely reduces isoflurane requirements.

IMPLICATIONS

In patients undergoing coronary artery bypass grafting, clonidine produces sedation and relieves anxiety as effectively as conventional premedication. Clonidine does not uniquely alter the dose of sufentanil inducing unconsciousness or electroencephalographic slowing, but it significantly reduces isoflurane requirements.

Safety and efficacy of early extubation of elderly coronary artery bypass surgery patients

OBJECTIVE

Early extubation and fast-track management protocols on younger, low-risk patients result in shorter hospital stays and decreased costs. The impact of such protocols on elderly patients undergoing coronary artery bypass graft (CABG) surgery is not presently known.

DESIGN

A matched retrospective cohort study.

SETTING

A university teaching hospital.

PARTICIPANTS

Six hundred ninety-eight consecutive patients undergoing isolated CABG between January 1995 and September 1996.

INTERVENTIONS

Three hundred seventy-seven patients underwent early extubation, defined as extubation within 8 hours of arrival in the intensive care unit. They were divided into groups of patients 70 years of age and younger (n = 263) and patients older than 70 years of age (n = 114).

RESULTS

The mean length of stay (LOS) for all patients extubated within 8 hours or less was 5.5 days versus 8.4 days for patients who underwent later extubation (p < 0.0001). The percentage of patients undergoing early extubation was greater for the younger cohort (59% v 48%; p < 0.003) compared with the older cohort of patients. Analysis of demographics showed the older patients to have a greater incidence of peripheral vascular disease, congestive heart failure, and prior strokes (p < 0.05). Although the intensive care unit LOS was similar, postoperative LOS was 5.3 +/- 1.8 days for the younger patients versus 6.1 +/- 2.6 days for the older patients (p = 0.001). The overall surgical mortality rate was 2.6% (18/698), and there were no deaths among patients undergoing early extubation. Reintubation rate was negligible in both groups of patients.

CONCLUSION

This study confirms the safety and efficacy of early extubation among elderly patients undergoing CABG. Elderly patients have more comorbid conditions, yet a significant number can be extubated early, with resultant shortened LOSs.

Early extubation following coronary artery bypass surgery: a prospective randomized controlled trial. The Fast Track Cardiac Care Team

STUDY OBJECTIVES

To determine the safety of early extubation (EE) after coronary artery surgery.

DESIGN

Prospective randomized controlled trial.

SETTING

The cardiac surgery operating room and ICU of a university-affiliated teaching hospital.

PATIENTS

One hundred eligible patients presenting for elective coronary artery surgery.

INTERVENTIONS

Patients randomized to the EE group were administered a reduced dose of fentanyl (15 microg/kg) and an anesthetic compatible with EE, while patients randomized to the conventional extubation (CE) group were given fentanyl (50 microg/kg).

MEASUREMENTS AND RESULTS

The time to extubation in the EE group (median, 240 min; range, 30 to 930 min) was significantly less than the CE group (median, 420 min; range, 125 to 1,140 min) (p<0.01). Twenty patients were withdrawn from the study according to protocol guidelines. There were no cases of reintubation or complications attributable to EE.

CONCLUSIONS

By using an appropriate anesthetic technique and postoperative management, EE can be achieved following coronary artery bypass surgery without major complications.

Propofol-based versus fentanyl-isoflurane-based anesthesia for cardiac surgery

OBJECTIVE

To evaluate drug costs, time of mechanical ventilation, complications, and hospital length of stay comparing propofol-based with fentanyl-isoflurane-based anesthesia.

DESIGN

A prospective, randomized study.

SETTING

A university-affiliated, tertiary care community hospital.

PARTICIPANTS

Seventy patients undergoing primary coronary artery bypass surgery.

INTERVENTIONS

Patients were randomized to either a low-dose fentanyl-isoflurane or a lower-dose fentanyl-isoflurane anesthetic supplemented with a continuous infusion of propofol.

MEASUREMENTS AND MAIN RESULTS

Fentanyl-isoflurane anesthesia was significantly less expensive ($50.03+/-$27.26 v $121.69+/-$31.40) for anesthesia drugs and ($58.08+/-$27.39 v $129.91+/-$31.52) for total drug costs. There was also a trend for patients in the fentanyl-isoflurane group to be extubated slightly sooner (388+/-202 v 449+/-252 min) and go home sooner (5.1+/-1.8 v 6.0+/-3.0 days).

CONCLUSION

Fentanyl-isoflurane provides an inexpensive anesthetic that permits as prompt an extubation as propofol, thus conserving resources for other patients.

Fast-track cardiac surgery: economic implications in postoperative care

Economics is the main driving force in changing health care delivery in the 90s. The motto is to "do more with less." Cost containment and efficient resource utilization swing the pendulum back to the debate of early tracheal extubation in cardiac surgical patients. Recently, it has been confirmed that fast-track cardiac anesthesia is both safe and cost-effective. This article describes the economic implications in postoperative care of fast-track cardiac surgery. First, the developments of early extubation postcardiac surgery and the factors that influence costs of cardiac surgery are reviewed. Second, the morbidity outcome, utilization, and cost implications of early extubation in cardiac surgery are summarized. The perioperative cost analysis in fast-track cardiac surgery, including the cost of complications and resource utilization, is outlined. Lastly, it is important to realize that early extubation does not necessarily mean earlier intensive care unit or hospital discharge. To achieve a maximum cost benefit from early extubation, team organization of a fast-track cardiac surgery program for the perioperative management of these patients is detailed.

Light versus heavy sedation after cardiac surgery: myocardial ischemia and the stress response. Maritime Heart Centre and Dalhousie University

The influence of light versus heavy sedation after coronary artery bypass graft (CABG) surgery on the development of postoperative myocardial ischemia has not been described. After uncomplicated CABG surgery, 50 patients were randomly assigned to receive LOW (n = 24; target Ramsay Sedation Score [RSS] = 2) or HIGH (n = 26; target RSS = 4) sedation with propofol. Analgesia was provided to maintain a visual analog scale (VAS) pain score <7. Myocardial ischemia was identified perioperatively using continuous 3-lead Holter monitoring. By measuring creatine kinase (CK) MB levels preoperatively, at entry to the intensive care unit (ICU), and every 12 h for 48 h; and by obtaining serial 12-lead electrocardiograms (ECG) (preoperatively; 2, 4, 12, 24, and 48 h after ICU admission, 8:00 AM the morning after surgery; and 5 min pre- and postextubation), myocardial infarction was identified. Endocrine stress response was assessed by measuring serum cortisol levels preoperatively, on admission to the ICU, and 24 h postoperatively. In a subset of patients (LOW n = 10, HIGH n = 11), plasma and urinary catecholamine levels were also measured. There were no between-group differences in demographics, operative course, hemodynamic variables, or cortisol levels while in the ICU. The VAS pain score and target RSS were achieved and sustained, and they differed between groups. There were three myocardial infarctions in each group by CKMB criteria alone. No ECG-identifiable myocardial infarction occurred. The ST segment versus time curve (LOW 187 +/- 295 versus HIGH 1071 +/- 2137 mm/min) differed between groups. Urinary and plasma catecholamine levels were similar between groups over the observation period. We conclude that the use of a reduced sedation regimen in combination with adequate analgesia did not result in an increased endocrine stress response or risk of myocardial ischemia.

IMPLICATIONS

This randomized study of patients after coronary artery bypass surgery examined whether light (versus heavy) sedation with propofol in the intensive care unit was associated with an increased degree of myocardial ischemia. Using techniques to detect myocardial ischemia, including Holter monitoring, electrocardiogram, and myocardial enzyme measurements, no differences were found. We conclude that light sedation does not increase the endocrine stress response or the risk of myocardial infarction.