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

Evaluation of dexmedetomidine versus propofol-based sedation therapy in mechanically ventilated cardiac surgery patients at a tertiary academic medical center

Management of pain and sedation therapy is a vital component of optimizing patient outcomes; however, the ideal pharmacotherapy regimen has not been identified in the postoperative cardiac surgery population. We sought to evaluate efficacy and safety outcomes between postoperative mechanically ventilated cardiac surgery patients receiving dexmedetomidine versus propofol therapy upon arrival to the intensive care unit (ICU). We conducted a single center, descriptive study of clinical practice at a 20-bed cardiac surgery ICU in a tertiary academic medical center. Adult mechanically ventilated postcardiac surgery patients who received either dexmedetomidine or propofol for sedation therapy upon admission to the ICU between October 20, 2006 and December 15, 2006 were evaluated. A pharmacy database was used to identify patients receiving dexmedetomidine or propofol therapy for perioperative sedation during cardiac surgery. Patients were matched according to surgical procedure type. Fifty-six patients who received either dexmedetomidine (n = 28) or propofol (n = 28) were included in the analysis. No differences in the ICU length of stay (58.67 ± 32.61 vs. 61 ± 33.1 hours; P = 0.79) and duration of mechanical ventilation (16.21 ± 6.05 vs. 13.97 ± 4.62 hours; P = 0.13) were seen between the propofol and dexmedetomidine groups, respectively. Hypotension (17 [61%] vs. 9 [32%]; P = 0.04), morphine use (11 [39.3%] vs. 1 [3.6%]; P = 0.002), and nonsteroidal anti-inflammatory use (7 [25%] vs. 1 [3.6%]; P = 0.05) occurred more during dexmedetomidine therapy versus propofol. Dexmedetomidine therapy resulted in a higher incidence of hypotension and analgesic consumption compared with propofol-based sedation therapy. Further evaluation is needed to assess differences in clinical outcomes of propofol and dexmedetomidine-based therapy in mechanically ventilated cardiac surgery patients.

Heparinized cardiopulmonary bypass circuits and low systemic anticoagulation: an analysis of nearly 6000 patients undergoing coronary artery bypass grafting

OBJECTIVE

Heparin coating of cardiopulmonary bypass circuits reduces the inflammatory response and increases the thromboresistance during extracorporeal circulation. These properties enables a lower systemic heparin dose, which has been shown to reduce the need for blood transfusions. Experience with this technique accumulated over 11 years has been analyzed.

METHODS

All patients underwent on-pump coronary artery bypass grafting with heparin-coated circuits. Apart from some patients receiving a high intraoperative dose of aprotinin, the systemic heparin dose was reduced, with a lower level of an activated clotting time of 250 seconds during extracorporeal circulation. The overall strategy aimed at a fast-track regimen, with early extubation, minimal use of blood transfusions, and rapid postoperative recovery.

RESULTS

Altogether, 5954 patients were included; 1131 (19.0%) were female (median age, 70 years), and 4823 were male (median age, 65 years). The median additive EuroSCORE was 3 (range, 0-14; mean 3.5 ± 2.5). No significant signs of clotting were seen in any part of the extracorporeal circuit. Bank blood products were given to 427 (7.2%) patients. Median extubation time was 1.7 hours. The stroke rate was 1.0%, transient neurologic deficits occurred in 0.7%, and perioperative myocardial infarction occurred in 1.2%. On the fifth day, 88.1% of the patients were physically rehabilitated and ready for discharge. Thirty-day mortality was 0.9% (54 patients).

CONCLUSIONS

The experience with this patient cohort including mostly low- to medium-risk patients with a relatively short cardiopulmonary bypass time indicates that coronary artery bypass grafting performed with heparin-coated circuits and reduced level of systemic heparinization is safe and results in a very satisfactory clinical course. No signs of clotting or other technical incidents were recorded.

Clinical guideline for nurse-led early extubation after coronary artery bypass: an evaluation

AIM

This paper is a report of an investigation of the development, implementation and outcomes of a clinical guideline for nurse-led early extubation of adult coronary artery bypass graft patients.

BACKGROUND

Healthcare knowledge translation and utilization is an emerging but under-developed research area. The complex context for guideline development and use is methodologically challenging for robust and rigorous evaluation. This study contributes one such evaluation.

METHODS

This was a mixed methods evaluation, with a dominant quantitative study with a secondary qualitative study in a single UK cardiac surgery centre. An interrupted time series study (N = 567 elective coronary artery bypass graft patients) with concurrent within person controls was used to measure the impact of the guideline on the primary outcome: time to extubation. Semi-structured interviews with 11 clinical staff, informed by applied practitioner ethnography, explored the process of guideline development and implementation. The data were collected between January 2001 and January 2003.

RESULTS

There was no change in the interrupted time series study primary outcome as a consequence of the guideline implementation. The qualitative study identified three themes: context, process and tensions highlighting that the guideline did not require clinicians to change their practice, although it may have helped maintain practice through its educative role.

CONCLUSION

Further investigation and development of appropriate methods to capture the dynamism in healthcare contexts and its impact on guideline implementation seems warranted. Multi-site mixed methods investigations and programmes of research exploring knowledge translation and utilization initiatives, such as guideline implementation, are needed.

Health-related quality of life after fast-track treatment results from a randomized controlled clinical equivalence trial

PURPOSE

This randomized clinical equivalence trial was designed to evaluate health-related quality of life (HRQoL) after fast-track treatment for low-risk coronary artery bypass (CABG) patients.

METHODS

Four hundred and ten CABG patients were randomly assigned to undergo either short-stay intensive care treatment (SSIC, 8 h of intensive care stay) or control treatment (care as usual, overnight intensive care stay). HRQoL was measured at baseline and 1 month, and one year after surgery using the multidimensional index of life quality (MILQ), the EQ-5D, the Beck Depression Inventory and the State-Trait Anxiety Inventory.

RESULTS

At one month after surgery, no statistically significant difference in overall HRQoL was found (MILQ-score P-value=.508, overall MILQ-index P-value=.543, EQ-5D VAS P-value=.593). The scores on the MILQ-domains, physical, and social functioning were significantly higher at one month postoperatively in the SSIC group compared to the control group (P-value=.049; 95%CI: 0.01-2.50 and P-value=.014, 95% CI: 0.24-2.06, respectively). However, these differences were no longer observed at long-term follow-up.

CONCLUSIONS

According to our definition of clinical equivalence, the HRQoL of SSIC patients is similar to patients receiving care as usual. Since safety and the financial benefits of this intervention were demonstrated in a previously reported analysis, SSIC can be considered as an adequate fast-track intensive care treatment option for low-risk CABG patients.

Modifiable and nonmodifiable risk factors for postoperative delirium after cardiac surgery with cardiopulmonary bypass

OBJECTIVES

Postoperative delirium after cardiac surgery is associated with increased morbidity and mortality as well as prolonged stay in both the intensive care unit and the hospital. The authors sought to identify modifiable risk factors associated with the development of postoperative delirium in elderly patients after elective cardiac surgery in order to be able to design follow-up studies aimed at the prevention of delirium by optimizing perioperative management.

DESIGN

A post hoc analysis of data from patients enrolled in a randomized controlled trial was performed.

SETTING

A single university hospital.

PARTICIPANTS

One hundred thirteen patients aged 65 or older undergoing elective cardiac surgery with cardiopulmonary bypass.

INTERVENTIONS

None. MEASUREMENTS AND MAINS RESULTS: Screening for delirium was performed using the Confusion Assessment Method (CAM) on the first 6 postoperative days. A multivariable logistic regression model was developed to identify significant risk factors and to control for confounders. Delirium developed in 35 of 113 patients (30%). The multivariable model showed the maximum value of C-reactive protein measured postoperatively, the dose of fentanyl per kilogram of body weight administered intraoperatively, and the duration of mechanical ventilation to be independently associated with delirium.

CONCLUSIONS

In this post hoc analysis, larger doses of fentanyl administered intraoperatively and longer duration of mechanical ventilation were associated with postoperative delirium in the elderly after cardiac surgery. Prospective randomized trials should be performed to test the hypotheses that a reduced dose of fentanyl administered intraoperatively, the use of a different opioid, or weaning protocols aimed at early extubation prevent delirium in these patients.

Impact of dexmedetomidine on analgesic requirements in patients after cardiac surgery in a fast-track recovery room setting

STUDY OBJECTIVE

To compare postoperative opioid requirements in patients who received dexmedetomidine versus propofol after cardiac surgery.

DESIGN

Retrospective cohort study.

SETTING

Large, community teaching hospital that uses a fast-track cardiovascular recovery unit (CVRU) model.

PATIENTS

One hundred adults who underwent coronary artery bypass graft surgery and/or valvular surgery, and who received either dexmedetomidine (50 patients) or propofol (50 patients) for perioperative sedation.

MEASUREMENTS AND MAIN RESULTS

Patients were matched according to surgery type and left ventricular ejection fraction. Opioid requirements were assessed over two time intervals: from arrival in the CVRU to discontinuation of the sedative infusion, and from CVRU arrival to CVRU discharge, up to a maximum of 72 hours if admission to the intensive care unit was necessary. All postoperative opioid doses were converted to morphine equivalents. Length of mechanical ventilation, quality of sedation, adverse drug events, and sedation-related costs were determined. Opioid requirements were significantly lower during the sedative infusion period for dexmedetomidine-treated patients than for propofol-treated patients (median [range] 0 [0-10 mg] vs 4 mg [0-33 mg], p<0.001), but not through the entire CVRU admission (median [range] 26 mg [0-119 mg] vs 30 mg (0-100 mg], p=0.284). The proportion of patients who did not require opioids during the infusion was significantly higher in the dexmedetomidine group compared with the propofol group (32 [64%] vs 13 [26%], p<0.001). No significant differences were noted between the groups for length of mechanical ventilation, quality of sedation, or adverse events. Sedation-related costs were significantly higher (approximately $50/patient higher) with dexmedetomidine (p<0.001).

CONCLUSION

Dexmedetomidine resulted in lower opioid requirements in patients after cardiac surgery versus those receiving propofol, but this did not result in shorter durations of mechanical ventilation, using a fast-track CVRU model.

Anesthesia in adult cardiac surgery without maintenance of muscle relaxants: a randomized clinical trial

There may be no need for muscle paralysis during cardiac surgery when adequate anesthesia is provided. We studied intra- and post-operative conditions during cardiac surgery without maintenance muscle relaxant therapy. Eighty adult patients who were candidates for elective coronary artery bypass graft surgery were randomly allocated into two groups. In the noMR or study group (noMR group; n = 40) only an intubation dose of cisatracurium (0.15 mg kg(-1)) was administrated, as opposed to the control group (MR group; n = 40), who had a continuous infusion added to the intubation dose. The anesthesia level was maintained at a Bispectral score of 40-50 using a propofol infusion. A remifentanil infusion was titrated to control patient hemodynamic response. During surgery, any minor (fine body or respiratory muscle movements) or major (coarse body movements or bucking/caught) movements were recorded. Postoperatively, analgesia was provided by remifentanil. The surgical condition was classified into three states: good (no movement), acceptable (minor movements), or poor (major movements). Anesthesia, surgery and postoperative characteristics were compared between the two groups. Statistical analysis was performed in only 78 patients (noMR = 38, MR = 40). The demographic and preoperative characteristics of the two groups were comparable. Intra-operative propofol consumption was the same, but significantly more remifentanil was used in the noMR group (p = 0.001). Post-operative characteristics and complication rates did not differ between the two groups. There were no movements in the MR group patients, while in the noMR group one patient had major movement and three had minor movements. We concluded that omitting maintenance muscle relaxants in adult cardiac surgery or eliminating residual muscle paralysis at the end of the surgery without improving early outcome can increase patient intra-operative movement risk.

The pharmacokinetic profile of recombinant human erythropoietin is unchanged in patients undergoing cardiac surgery

BACKGROUND

In anticipation of future studies, we examined the pharmacokinetics profile of erythropoietin (EPO) in patients undergoing cardiac surgery.

METHODS

Cardiac surgical patients were enrolled into one of six groups: four cardiopulmonary bypass (CPB) groups [placebo (n = 6), 250 IU/kg EPO (n = 3), 500 IU/kg EPO (n = 3), and 500 IU/kg EPO, two doses (n = 6)] and two off-pump coronary artery bypass (OPCAB) groups [placebo (n = 3) and 500 IU/kg EPO (n = 3)]. The EPO was administered prior to anesthesia and 10 min after CPB (if required). Blood samples for serum EPO were collected at baseline, 10 min after dosing, 5 min after sternotomy, during CPB or the equivalent for OPCAB (5, 15, 45, 60 min), and post-CPB (5, 15, 45, and 60 min, 6, 12 and 24 h, and daily until day 5).

RESULTS

Endogenous EPO increased within 24 h of surgery in the placebo group and remained elevated. There was approximately a 40% decrease in serum EPO concentration at the initiation of CPB due to an increase in circulatory blood volume. There were no differences in apparent volume of distribution in the plasma (Vc) (42.2 +/- 9.9, 39.8 +/- 6.3, 42.3 +/- 14.0 mL/kg), clearance (CL) (4.63 +/- 1.14, 3.44 +/- 0.68, 4.27 +/- 0.52 mL h/kg), and t((1/2)) (16.4 +/- 8.0 16.9 +/- 10.6, 22.4 +/- 9.3 h) between the CPB treatment groups. The pharmacokinetic profile of EPO in the OPCAB group was similar to that for the CPB groups: Vc = 39.3 +/- 7.0 mL/kg, CL = 4.98 +/- 0.17 mL h/kg and t((1/2)) = 17.1 +/- 18.1 h.

CONCLUSIONS

CPB had no apparent effect on the pharmacokinetics of EPO.

Optimizing early extubation after coronary surgery

Early extubation after isolated coronary artery bypass surgery was assessed retrospectively in 545 of 779 patients treated by the same surgical team over one year. All underwent extubation within 10 hr of arrival at the cardiothoracic intensive care unit: 343 in < 6 hr and 202 in 6-10 hr. Operative mortality was 2.2%. Group comparisons revealed that patients who had earlier extubation were younger (61 vs. 66 years; p < 0.001), more likely to be male (72.5% vs. 61.3%; p < 0.05), with a shorter aortic crossclamp time (49.2 +/- 15.0 vs. 53.3 +/- 14.0 min; p < 0.05), cardiopulmonary bypass time (65 +/- 18.4 vs. 72.2 +/- 19.2 min; p < 0.05), intensive care unit stay (18.8 +/- 5.6 vs. 22.4 +/- 3.2 hr; p < 0.05) and postoperative hospital stay (5.2 +/- 2.2 vs. 6.0 +/- 2.4 days; p = 0.01). Extubation < 6 hr after cardiopulmonary bypass may accelerate recovery. The finding of no significant differences in clinical parameters between the groups suggests that efforts to further reduce the time to extubation might be worthwhile.

Cardiovascular effects of mechanical ventilation and weaning

Because of their anatomic position in the closed thoracic cavity, the heart and lungs interact during each ventilation cycle. The application of mechanical ventilation and subsequent removal changes normal ventilatory mechanics and produces alterations in cardiac preload and afterload that influence global hemodynamic state and delivery of oxygen and nutrients. Adverse cardiovascular responses to mechanical ventilation and weaning from ventilation include hemodynamic alterations and instability, myocardial ischemia, autonomic dysfunction, and cardiac dysrhythmias. Clinicians must have a clear understanding of the cardiovascular effects of mechanical ventilation and weaning so they may anticipate, recognize, and effectively manage negative effects and improve patient outcomes.

Feasibility of the fast-track recovery program after cardiac surgery in Japan

OBJECTIVES

The purpose of this study was to determine if a fast-track recovery protocol that is applied in other countries can be used in the present Japanese medical system. Second, we wanted to evaluate the differences if the protocol was adapted from the viewpoint of cost saving, postoperative hospital stay, and adverse complications.

METHODS

We retrospectively analyzed 94 consecutive patients who underwent cardiovascular surgery with conventional techniques on cardiac arrest requiring cardiopulmonary bypass between July 1, 2004 and June 30, 2006. We started our fast-track recovery protocol from July 1, 2005. We compared the results of the conventional group (before July 1, 2005) and the fast-track recovery protocol group (after July 1, 2005). Moreover, we used a unique questionnaire and investigated how the patients in the fast-track group felt about the short hospital stay postoperatively.

RESULTS

The mean postoperative hospital stay was 36.7 +/- 6.0 days for the conventional group and 15.0 +/- 12.4 days for the fast-track group, with a statistically significant difference (P = 0.01). The mean cost fell by almost half, from 712545 yen to 383268 yen (P = 0.038). The difference in complication rates was not statistically significant.

CONCLUSION

A fast-track recovery protocol can be safely adapted to patients in the Japanese system without increasing the mortality or morbidity rate. Based on our unique questionnaires, the most important factor was sufficient and repeated explanations preoperatively to the patients and their family members. Second, good pain control with routine use of acetaminophen and sporadic morphine orally has a great effect on the patients' recovery.

Impact of the opening of a specialized cardiac surgery recovery unit on postoperative outcomes in an academic health sciences centre

PURPOSE

It is controversial as to whether cardiac surgery patients are optimally managed in a mixed medical-surgical intensive care unit (ICU) or in a specialized postoperative unit. We conducted a prospective cohort study in an academic health sciences centre to compare outcomes before and following the opening of a specialized cardiac surgery recovery unit (CSRU) in April 2005.

METHODS

The study cohort included 2,599 consecutive patients undergoing coronary artery bypass grafting (CABG), valve and combined CABG-valve procedures from April 2004 to March 2006. From April 2004 to March 2005 (year 1) all patients received postoperative care in mixed medical-surgical ICUs at two different sites staffed by critical care consultants, fellows and residents. From April 2005 until March 2006 (year 2) patients were cared for in a newly-established CSRU on one site staffed by cardiac anesthesiology fellows, a nurse practitioner and consultants in critical care, cardiac anesthesiology and cardiac surgery. The effect of this change on in-hospital mortality, the incidence of ten major postoperative complications, postoperative ventilation hours, readmission rates and case cancellations due to a lack of capacity was assessed using Chi-square or Wilcoxon tests, where appropriate.

RESULTS

Coronary artery bypass grafting, valve and combined CABG-valve mortality rates were similar in years 1 and 2. There was a significant reduction in the composite major complication rate (16.3% to 13.0%, P=0.02) and in median postoperative ventilation hours (8.8 vs 8.0 hr, P=0.005) from year 1 to 2. On multivariable logistic regression analysis, the pre-merger interval (year 1) was a significant independent predictor of the occurrence of death or major complications.

CONCLUSION

A specialized CSRU with a multi-disciplinary consultant model was associated with stable or improved outcomes postoperatively, when compared to a mixed medical- surgical ICU model of cardiac surgical care.

Logistic Risk Model for Prolonged Ventilation After Adult Cardiac Surgery

BACKGROUND

The aim of this study was to develop a multivariate risk prediction model for prolonged ventilation after adult cardiac surgery.

METHODS

This is a retrospective analysis of prospectively collected data on 12,662 consecutive patients undergoing adult cardiac surgery between April 1997 and March 2005. Data were randomly split into a development dataset (n = 6,000) and a validation dataset (n = 6,662). A multivariate logistic regression analysis was undertaken using a forward stepwise technique to identify independent risk factors for prolonged ventilation (defined as ventilation greater than 48 hours). The area under the receiver operating characteristic (ROC) curve and the Hosmer-Lemeshow goodness-of-fit statistic were calculated to assess the performance and calibration of the model, respectively. Patients were split into low-, medium-, and high-risk groups based on their predicted probability of prolonged ventilation.

RESULTS

Three hundred thirty-three patients had prolonged ventilation (5.5%). Independent variables, identified with prolonged ventilation, are shown with relevant coefficient values and p values as follows: (1) age 65 to 75 years, 0.7831, p < 0.001; (2) age 75 to 80 years, 1.5605, p < 0.001; (3) age greater than 80 years, 1.7115, p < 0.001; (4) forced expiratory volume less than 70% predicted, 0.3707, p = 0.013; (5) current smoker, 0.5315, p = 0.001; (6) serum creatinine 125 to 175 micromol/L, 0.6371, p < 0.001; (7) serum creatinine greater than 175 micromol/L, 1.3817, p < 0.001; (8) peripheral vascular disease, 0.6212, p < 0.001; (9) ejection fraction less than 0.30, 0.7839, p < 0.001; (10) myocardial infraction less than 90 days, 0.7415, p < 0.001; (11) preoperative ventilation, 1.3540, p = 0.004; (12) prior cardiac surgery, 0.8946, p < 0.001; (13) urgent surgery, 0.4414, p = 0.004; (14) emergency surgery, 0.7421, p = 0.005; (15) mitral valve surgery, 0.7715, p < 0.001; (16) aortic surgery, 1.7043, p < 0.001; and (17) use of cardiopulmonary bypass, 0.4052, p = 0.025; intercept, -4.7666. The ROC curve for the predicted probability of prolonged ventilation was 0.79, indicating a good discrimination power. The prediction equation was well-calibrated, predicting well at all levels of risk. A simplified additive scoring system was also developed. In the validation dataset, 5.1% of patients had prolonged ventilation compared with 5.4% expected. The ROC curve for the validation dataset was 0.75.

CONCLUSIONS

We developed a contemporaneous multivariate prediction model for prolonged ventilation after cardiac surgery. This tool can be used in day-to-day practice to calculate patient-specific risk by the logistic equation or a simple scoring system with an equivalent predicted risk.

Influence of fast-track recovery after coronary artery bypass in the elderly

We retrospectively analyzed 711 consecutive patients who had isolated coronary artery bypass grafting between January 2000 and December 2004; 572 younger patients (< 70 years) were compared with 139 elderly patients (> or = 70 years). A rapid recovery program based on an anesthetic protocol for early extubation was applied to all patients. The overall hospital mortality rate was 3.3% for the younger group and 4.3% for the elderly group. There were no significant differences in rates of hospital mortality and postoperative complications between the two groups. Early extubation was achieved in significantly more younger (71%) compared to elderly (57%) patients. Rapid recovery with discharge before the 5(th) postoperative day was achieved in 19% of the elderly compared to 48% of the younger patients. Patients in the younger group were discharged from hospital earlier (6.8 +/- 0.3 vs 8.0 +/- 8.5 days). Application of fast-track treatment in an elderly population appears to be a safe and effective approach if used on a selective basis when criteria for early extubation are met.

Determinants of Early Discharge From the Intensive Care Unit After Cardiac Operations

BACKGROUND

The length of stay in the intensive care unit is one of the factors limiting operating room utilization in cardiac surgery. We investigated the impact of a goal-oriented program aimed at discharging the patients from the intensive care unit the morning after the operation within a comprehensive model including other explanatory variables.

METHODS

A multivariable predictive model for early discharge from the intensive care unit was established using a stepwise forward logistic regression. The analysis was retrospectively conducted on 9120 consecutive patients undergoing cardiac surgical procedures at our institution.

RESULTS

A total of 1874 patients were discharged early from the intensive care unit. Factors associated with early discharge were ejection fraction, lowest hematocrit on cardiopulmonary bypass, lowest temperature on cardiopulmonary bypass, and the presence of the goal-oriented strategy (odds ratio, 5.5; 95% confidence interval, 4.8 to 6.3). Factors associated with late discharge were age, preoperative serum creatinine value, unstable angina, congestive heart failure, redo operation, combined operation, and cardiopulmonary bypass duration. An extubation time of 4 hours after the arrival in the intensive care unit was associated with the peak rate of early discharge. Patients being early discharged according to the goal-oriented strategy did not demonstrate a different complication rate compared with patients treated with a standard strategy.

CONCLUSIONS

Early discharge from the intensive care unit depends on a combination of preoperative and intraoperative factors, but most of all on the presence of a goal-oriented strategy. A very early extubation is not required for an early discharge from the intensive care unit.

Fast-track failure after cardiac surgery: Development of a prediction model*

OBJECTIVE

Risk factors for unsuccessful fast-tracking of cardiac surgery patients have not been collectively defined in the literature. The aim of this study was to determine risk factors for fast-track failure and incorporate them into a predictive fast-track failure score.

DESIGN

Prospective observational study.

SETTING

Cardiothoracic Department of St Mary's Hospital, London.

PATIENTS

Data were collected from April 2003 to April 2005 including 1,084 patients undergoing heart surgery who were admitted into the fast-track unit.

INTERVENTIONS

Multifactorial logistic regression was used to develop a propensity score for estimating the likelihood of fast-track failure.

MEASUREMENTS AND MAIN RESULTS

One hundred and sixty-nine patients failed fast-track management (15.6%). Independent predictors for fast-track failure were impaired left ventricular function with or without recent acute coronary syndrome (odds ratios 2.89 and 1.65 respectively), re-do operation (one, two, or more vs. none, odds ratio 1.75, 7.98), extracardiac arteriopathy (odds ratio 2.63), preoperative intra-aortic balloon pump (odds ratio 3.09), raised serum creatinine in micromol/L (120-150, >150 vs. <120, odds ratio 1.57, 11.24), and nonelective (odds ratio 3.43) and complex surgery (odds ratio 2.70). Model validation showed very good discrimination (area under the curve = 0.815) and calibration (ĉ statistic = 8.527, p = .129).

CONCLUSIONS

The fast-track failure score incorporates several preoperative factors and has been successfully internally validated; after undergoing external validation and possible recalibration it may be used as a tool to facilitate planning and flow of cardiac surgery patients, based on the predicted probability of failure. Application of this score may limit fast-track failure rates and help to reduce morbidity and cost.

Hemodynamic Changes During Discontinuation of Mechanical Ventilation in Medical Intensive Care Unit Patients

• Background Cardiac dysfunction can prevent successful discontinuation of mechanical ventilation. Critically ill patients may have undetected cardiac disease, and cardiac dysfunction can be produced or exacerbated by underlying pathophysiology.

• Objective To describe and compare hemodynamic function and cardiac rhythm during baseline mechanical ventilation with function and rhythm during a trial of continuous positive airway pressure in medical intensive care patients.

• Methods A convenience sample of 43 patients (53% men; mean age 51.1 years) who required mechanical ventilation were recruited for this pilot study. Cardiac output, stroke volume, arterial blood pressure, heart rate, cardiac rhythm, and plasma catecholamine levels were measured during mechanical ventilation and during a trial of continuous positive airway pressure.

• Results One third of the patients had difficulty discontinuing mechanical ventilation. Successful patients had significantly increased cardiac output and stroke volume without changes in heart rate or arterial pressure during the trial of continuous positive airway pressure. Unsuccessful patients had no significant changes in cardiac output, stroke volume, or heart rate but had a significant increase in mean arterial pressure. The 2 groups of patients also had different patterns in ectopy. Concurrently, catecholamine concentrations decreased in the successful patients and significantly increased in the unsuccessful patients during the trial.

• Conclusions Patterns of cardiac function and plasma catecholamine levels differed between patients who did or did not achieve spontaneous ventilation with a trial of continuous positive airway pressure. Cardiac function must be systematically considered before and during the return to spontaneous ventilation to optimize the likelihood of success.

The decision-making processes of nurses when extubating patients following cardiac surgery: An ethnographic study

BACKGROUND

The movement towards research and evidence-based practice in health care demands that the best available evidence is applied to practice. At the same time, changes to role boundaries mean that nurses are assuming increased responsibility, especially in relation to decision making. While increasing, there has been limited consideration about the application of best evidence and decision making by nurses in the context of their clinical work.

OBJECTIVES

This study sought to explore the realities of research and evidence-based practice through an examination of the decision making of nurses when extubating patients following cardiac surgery.

DESIGN

The tradition of qualitative research and, more specifically, ethnography were used for the study.

SETTING

Data were gathered over an 18-month period during 1998 and 1999 within a Cardiothoracic Intensive Care Unit (CICU).

PARTICIPANTS

The sample comprised 43 nursing, 16 medical and two managerial staff. A purposive sample of five nurses, a cardiac surgeon, intensivist, CICU manager and Deputy Divisional Manager were included in interviews.

METHODS

All staff were included in participant observation. Semi-structured interviews were conducted with a purposive sample of nurses during the 6th and 14th months and with a purposive sample of other staff during the 16th month. Data were analysed using progressive focusing, data source triangulation and sensitising concepts to identify themes and categories.

RESULTS

The findings indicated that, despite the use of an unwritten physiologically based protocol for weaning and extubation, factors other than best evidence were significant in nurses' decision making. A range of personal, cultural and contextual factors including relationships, hierarchy, power, leadership, education, experience and responsibility influenced their decision making.

CONCLUSION

This study revealed, often disregarded, cultural, contextual and personal characteristics which combined to form a complex process of decision making. Providing new insight into research and evidence-based practice, the findings have implications for policy makers, educators, managers and clinicians and for the continued professional development of nursing.

Does fast-track treatment lead to a decrease of intensive care unit and hospital length of stay in coronary artery bypass patients? A meta-regression of randomized clinical trials*

OBJECTIVE

Evaluation of randomized, controlled clinical trials studying fast-track treatment in low-risk coronary artery bypass grafting patients.

DESIGN

Meta-regression.

PATIENTS

Low-risk coronary artery bypass grafting patients.

INTERVENTIONS

Fast-track treatments including (high or low) anesthetic dose, normothermia vs. hypothermia, and extubation protocol (within or after 8 hrs).

MEASUREMENTS

Number of hours of intensive care unit stay, number of days of hospital stay, prevalence of myocardial infarction, and death. Furthermore, quality of life and cost evaluations were evaluated. The epidemiologic and economic qualities of the different trials were also assessed.

MAIN RESULTS

A total of 27 studies evaluating fast-track treatment were identified, of which 12 studies were with major and 15 were without major differences in extubation protocol or anesthetic treatment or both. The use of an early extubation protocol (p=.000) but not the use of a low anesthetic dose (p=.394) or normothermic temperature management (p=.552) resulted in a decrease of the total intensive care unit stay of low-risk coronary artery bypass grafting patients. Early extubation was found to be an important determinant of the total hospital stay for these patients. An influence of the type of fast-track treatment on mortality or the prevalence of postoperative myocardial infarction was not observed. In general, the epidemiologic and economic qualities of included studies were moderate.

CONCLUSIONS

Although fast-track anesthetics and normothermic temperature management facilitate early extubation, the introduction of an early extubation protocol seems essential to decrease intensive care unit and hospital stay in low-risk coronary artery bypass grafting patients.

Reduced Atrial Fibrillation in Patients Immediately Extubated After Off-Pump Coronary Artery Bypass Grafting

BACKGROUND

We analyzed data from patients undergoing off-pump isolated coronary artery bypass grafting surgery (OPCABG) to determine if immediate extubation in the operating room affected the incidence of postoperative atrial fibrillation.

METHODS

The study group comprised 2,376 consecutive OPCABG patients operated on between January 1, 2000, and December 31, 2004, by 22 surgeons at 18 hospitals. The data were subjected to univariate, multivariate analysis of variance, and logistic analysis. Logistic regression of matched groups was used to eliminate the effect of some confounding variables.

RESULTS

Patients immediately extubated after surgery had a reduced incidence of atrial fibrillation (10.6% versus 18.5%; p < 0.001), shorter length of stay (4.8 +/- 3.5 versus 6.3 +/- 5.2 days; p < 0.001), and also reduced mortality (1.1% versus 2.4%; p = 0.04). Logistic analysis identified as significant factors for postoperative atrial fibrillation, postoperative ventilator usage (p < 0.001; odds ratio [OR] = 1.63; 95% confidence interval [CI]: 1.24 to 2.14), male sex (p = 0.002; OR = 1.51; 95% CI: 1.17 to 1.96), previous CABG (p = 0.005; OR = 0.43; 95% CI: 0.24 to 0.78). Congestive heart failure may also be a contributing factor. In patient groups matched for their risk of mortality, postoperative ventilator use (p < 0.001; OR = 1.80; 95% CI: 1.31 to 2.47), increasing age, and male sex were all statistically significant risk factors. When patient groups were matched on a combination of factors including preoperative beta-blocker usage, pulmonary disease, and smoking, postoperative ventilator use (p = 0.005; OR = 1.66; 95% CI: 1.16 to 2.38), along with increasing age, male sex, and previous CABG (reduced odds of atrial fibrillation developing) were statistically significant.

CONCLUSIONS

Immediate extubation after OPCABG appears to reduce the incidence of postoperative atrial fibrillation independent of comorbidities.

Core and skin surface temperature course after normothermic and hypothermic cardiopulmonary bypass and its impact on extubation time

BACKGROUND AND OBJECTIVE

Cardiopulmonary bypass is associated with temperature pertubations that influence extubation time. Common extubation criteria demand a minimum value of core temperature only. The aim of this prospective study was to test the hypothesis that changes in core and skin surface temperature are related to extubation time in patients following normothermic and hypothermic cardiopulmonary bypass.

METHODS

Forty patients undergoing cardiac surgery were studied; 28 patients had normothermic cardiopulmonary bypass (nasopharyngeal temperature >35.5 degrees C) and 12 had hypothermic cardiopulmonary bypass (28-34 degrees C). In the intensive care unit, urinary bladder temperature and skin surface temperature gradient (forearm temperature minus fingertip temperature: >0 degrees C = vasoconstriction, < or =0 degrees C = vasodilatation) were measured at 30-min intervals for 10 h postoperatively. At the same intervals, the patients were evaluated for extubation according to common extubation criteria.

RESULTS

On arrival in the intensive care unit the mean urinary bladder temperature was 36.8 +/- 0.5 degrees C in the normothermic group and 36.4+/-0.3 degrees C in the hypothermic group (P = 0.014). The skin surface temperature gradient indicated severe vasoconstriction in the both groups. The shift from vasoconstriction to vasodilatation was faster in normothermic cardiopulmonary bypass patients (138+/-65 min) than in patients after hypothermic cardiopulmonary bypass (186+/-61 min, P = 0.034). There was a linear relation between the time to reach a skin surface temperature gradient = 0 degrees C and extubation time (r2 = 0.56, normothermic group; r2 = 0.82, hypothermic group).

CONCLUSIONS

The transition from peripheral vasoconstriction to vasodilatation is related to extubation time in patients following cardiac surgery under normothermic as well as hypothermic cardiopulmonary bypass.

Patient-controlledversus nurse-controlled analgesia after cardiac surgery — a meta-analysis

BACKGROUND

Patient-controlled analgesia (PCA) has been advocated as superior to conventional nurse-controlled analgesia (NCA) with less risk to patients. This systematic review and meta-analysis sought to determine whether PCA improves clinical and resource outcomes when compared with NCA.

METHODS

A comprehensive search was undertaken to identify all randomized controlled trials of PCA vs NCA. Medline, Cochrane Library, Embase, and conference abstract databases were searched from the date of their inception to August 2005. The primary postoperative outcome was defined as mean visual analogue scale (VAS) scores. Secondary postoperative outcomes included cumulative morphine equivalents, intensive care unit (ICU) and hospital length of stay, postoperative nausea and vomiting, sedation, respiratory depression, and all-cause mortality. Odds ratios or weighted mean differences (WMD) and their 95% confidence intervals (CI) were calculated for discrete and continuous outcomes, respectively.

RESULTS

Ten randomized trials involving 666 patients were included. Compared to NCA, PCA significantly reduced VAS at 48 hr (WMD -0.73, 95% CI -1.19, -0.27), but not at 24 hr (WMD -0.19, 95% CI -0.61, 0.24). Cumulative morphine equivalents consumed were significantly increased at 24 hr (WMD 6.84 mg, 95% CI 0.97, 12.72 mg), and at 48 hr (WMD 10.46 mg 95% CI 2.02, 18.9 mg) for PCA compared with NCA. Ventilation times, length of ICU stay, length of hospital stay, patient satisfaction scores, sedation scores, and incidence of postoperative nausea and vomiting, respiratory depression, severe pain, discontinuations, and death were not significantly different between groups, but these outcomes were generally under-reported.

CONCLUSIONS

In postcardiac surgical patients, PCA increases cumulative 24 and 48 hr morphine consumption, and improves 48-hr VAS compared with NCA.

Short-stay intensive care after coronary artery bypass surgery: Randomized clinical trial on safety and cost-effectiveness*

OBJECTIVE

To evaluate the safety and cost-effectiveness of short-stay intensive care (SSIC) treatment for low-risk coronary artery bypass patients.

DESIGN

Randomized clinical equivalence trial.

SETTING

University Hospital Maastricht, the Netherlands.

PATIENTS

Low-risk coronary artery bypass patients.

INTERVENTIONS

A total of 600 patients were randomly assigned to undergo either SSIC treatment (8 hrs of intensive care treatment) or control treatment (care as usual, overnight intensive care treatment).

MEASUREMENTS

The primary outcome measures were intensive care readmissions and total hospital stay. The secondary outcome measures were total hospital costs, quality of life, postoperative morbidity, and mortality. Hospital costs consisted of the cost of hospital admission or admissions and outpatient costs.

MAIN RESULTS

The difference in intensive care readmission between the two groups of 1.13% was very small and not significantly different (p = .241; 95% confidence interval, -0.9% to 2.9%). The total hospital stay (p = .807; 95% confidence interval, 1.2 to -0.4) and postoperative morbidity were comparable between the groups. The SSIC group's quality of life improved more compared with the control group's quality of life (p = .0238; 95% confidence interval, 0.0012 to 0.0464). The total hospital costs for SSIC were significantly lower (95% confidence interval, -1,581 to -174) compared with those for the control group (4,625 and 5,441, respectively). The estimated incremental cost-effectiveness ratio (cost/delta quality-adjusted life months) thus showed the dominance of SSIC. Bootstrap and sensitivity analyses confirm the robustness of the study findings.

CONCLUSIONS

Compared with usual care, SSIC is a safe and cost-effective approach. SSIC can be considered as an alternative for conventional postoperative intensive care treatment for low-risk coronary artery bypass graft patients.

Readmission and mortality in patients undergoing off-pump coronary artery bypass surgery with fast-track recovery protocol

The development of less invasive methods for myocardial revascularization such as "off-pump" cardiac surgery, and new methods of anesthesia and postoperative care protocols such as "fast-track recovery" (FTRC), have contributed to a significant reduction in postoperative intensive care unit (ICU) and hospital length of stay after cardiac surgical procedures. The objectives of this study were to identify perioperative risk factors of prolonged hospital stay, hospital mortality, and readmission rates in off-pump coronary artery bypass surgery (CABG) patients undergoing the FTRC protocol. Eighty consecutive patients undergoing off-pump coronary artery bypass surgery with FTRC protocol were included in the study. For the first purpose of this protocol, early extubation is defined as removal of the endotracheal tube within 6 h of arrival at the surgical ICU. The second purpose was to obtain a minimal length of stay in the ICU (<24 h) and hospital discharge within 5 days. We analyzed the influence of the preoperative, intraoperative, and postoperative variables on prolonged hospital stay, hospital mortality, and hospital readmission. Three patients died during hospitalization, giving a hospital mortality rate of 3.75%. The causes of hospital death were massive stroke and sepsis. Using multivariate logistic regression analysis, hypertension (P = 0.0185), postoperative stroke (P = 0.0001), and sternal infection (P = 0.0007) were identified as independent predictors of hospital mortality. Mean hospital length of stay was 4.23 +/- 0.75 days. Univariate and multivariate logistic regression analysis revealed that postoperative blood use (P = 0.0095) was the major independent predictor of prolonged hospital stay. During the 30-day observation period, seven patients were readmitted. One of these patients died on postoperative day 45 from mediastinitis and sepsis. Multivariate logistic regression analysis identified age (P = 0.0033) and hypertension (P = 0.045) as independent predictors of hospital readmission. FTRC protocols can be performed safely in patients with off-pump CABG, and the mortality and readmission rates following this protocol were found to be within acceptable ranges.

Opioid-sparing effects of diclofenac and paracetamol lead to improved outcomes after cardiac surgery

OBJECTIVE

This study assessed the analgesic efficacy, side effects, time to extubation, and oxygenation of 3 analgesic regimens after coronary artery bypass surgery using diclofenac, paracetamol, and placebo suppositories.

DESIGN

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

SETTING

Referral center for cardiothoracic surgery at a university hospital.

PARTICIPANTS

Sixty consenting adults scheduled for elective coronary artery bypass grafting (CABG).

INTERVENTIONS

Patients were divided into 3 groups postoperatively: diclofenac/paracetamol: diclofenac, 100 mg rectally, and paracetamol, 1 g rectally. Diclofenac was repeated after 18 hours and paracetamol every 6 hours for 24 hours; diclofenac: diclofenac as in diclofenac/paracetamol, with placebos replacing paracetamol; and placebo: 2 placebo suppositories at same times as diclofenac/paracetamol. All patients received morphine patient-controlled analgesia.

RESULTS

Twenty-four hour morphine consumption with diclofenac/paracetamol was 12 +/- 6 mg, diclofenac 22 +/- 13 mg, and placebo 37 +/- 15 mg (diclofenac/paracetamol and diclofenac, p = 0.0003 and p = 0.0159 compared with placebo). Patients in the placebo group had significantly greater pain scores at 12 and 24 hours compared with diclofenac/paracetamol and diclofenac. Extubation time was significantly prolonged in the placebo group compared with the diclofenac/paracetamol and diclofenac groups (mean [SD] minutes diclofenac/paracetamol, diclofenac, and placebo 478 [150], 487 [257], and 710 [326], respectively). Oxygenation following extubation was significantly lower in the placebo group compared with the diclofenac/paracetamol and diclofenac groups (mean [SD] mmHg: diclofenac/paracetamol, diclofenac, and placebo 175 [44], 157 [43], and 117 [22], respectively). Episodes of nausea and vomiting were significantly less in the diclofenac/paracetamol and diclofenac groups than in the placebo group (46% and 51% reduction, respectively). all groups had similar blood loss and change in serum creatinine.

CONCLUSION

Diclofenac alone or with paracetamol has a significant opioid-sparing effect after CABG, producing more rapid extubation and better oxygenation.

Routine Immediate Extubation After Off-Pump Coronary Artery Bypass Surgery: 514 Consecutive Patients

OBJECTIVE

The purpose of this study was to evaluate the feasibility of routine immediate extubation in patients undergoing off-pump coronary artery bypass surgery.

DESIGN

Case series.

SETTING

Private hospital.

PARTICIPANTS

Five hundred forty-eight consecutive patients undergoing off-pump coronary bypass surgery, representing 5 years of a single anesthesiologist's practice, were evaluated for routine immediate extubation. Thirty-four patients were excluded because they were already intubated, in preoperative cardiogenic shock, or converted to on-pump during the procedure.

INTERVENTION

Patients received general anesthesia or general anesthesia plus thoracic epidural analgesia (25%) and underwent off-pump coronary bypass surgery.

MEASUREMENTS AND MAIN RESULTS

All 514 patients who were intended to be immediately extubated were expeditiously extubated in the operating room. The numbers of reintubations, morbidity, and mortality were low.

CONCLUSIONS

Routine immediate extubation of most off-pump coronary artery bypass patients appears feasible and most probably safe.

Reporting unplanned extubation

Between 1995 and 2002 seven clinical audits were undertaken in consecutive periods over twelve months to determine the frequency and risk factors associated with reported unplanned extubation (UE) within a 22-bed general and surgical Intensive Care Unit (ICU). Nursing and medical staff provided information on the patient's age, diagnosis, mental status, precipitating causes and investigations/treatment ordered. Following the first audit, modifications were made to include anonymous reporting. Additional information was also obtained on the patient's position, sedation regimen, method of endotracheal tube (ETT) placement and the use of physical restraints. A clinical indicator was established to monitor the UE incidence based as a rate of UE per 100 patients. Audit results were between 1.06% and 4.86% with an aggregate rate from 1995 to 2002 of 2.6%. This rate compares favourably with the range of 2.8-22.5% reported in the literature. Over the survey periods, 28-60% of patients were assessed as being confused or agitated, 47-67% restrained and 53-70% sedated. The UE reported rate initially increased when anonymous reporting was introduced from 1.06% to 4.86%. Unplanned extubation incidence subsequently decreased in Surgical ICU following the introduction of clinical pathways, early weaning and nurse led extubation. Monitoring UE in ICU provides important information on the quality of care. We would recommend a system of anonymous reporting to more freely reflect incidence.

[Continuous infusion of remifentanil and target-controlled infusion of propofol for coronary surgery in elderly patients: comparison with continuous infusion of remifentanil and propofol]

OBJECTIVES

Comparison of the length of mechanical ventilation and postoperative complications after coronary surgery in elderly patients anaesthetised with propofol associated with either alfentanil or remifentanil.

STUDY DESIGN

Retrospective study with an historic control group.

PATIENTS

Three hundred thirty-eight consecutive patients (75-year-old or more) undergoing isolated coronary surgery. One hundred and fifty seven patients operated between January 1998 and June 2000 received alfentanil (1 microg/kg/minute) with a manually control infusion of propofol, 181 operated between July 2000 and 2002, remifentanil 0.25 microg/kg/minute with target controlled infusion of propofol (target blood concentration: 1.5 to 2 microg/ml).

METHODS

The two groups were compared for preoperative and surgical data. The length of mechanical ventilation, stay in ICU and the main postoperative complications were compared between the two groups.

RESULTS

Length of mechanical ventilation was significantly reduced in the remifentanil group (6 +/- 9 h vs. 13 +/- 63 h ; p <0.0001), 70% of the patients were extubated before the 6th postoperative hours against 53% in the alfentanil group (p =0.0023). This was not associated with a reduction of stay in ICU or postoperative complications. During surgery, an increased used of vasopressor was observed in the remifentanil group (40.2% vs 2.4% ; p <0.0001) with a postoperative elevation of blood concentration of CKMb (35.7 +/- 38.2 microg/l, vs. 27.7 +/- 31.9 microg/l, p =0.02).

CONCLUSION

Elderly patients undergoing coronary surgery were extubated earlier with remifentanil. However, this had no effect on duration of ICU stay but was associated with an increased used of vasopressor.

Parasternal Block and Local Anesthetic Infiltration with Levobupivacaine After Cardiac Surgery with Desflurane: The Effect on Postoperative Pain, Pulmonary Function, and Tracheal Extubation Times

Early tracheal extubation has become common after cardiac surgery. Anesthetic techniques designed to achieve this goal can make immediate postoperative analgesia challenging. We conducted this randomized, placebo-controlled, double-blind study to investigate the effect of a parasternal block on postoperative analgesia, respiratory function, and extubation times. We enrolled 20 patients having cardiac surgery via median sternotomy; 17 patients completed the study. A de-sflurane-based, small-dose opioid anesthetic was used. Before sternal wire placement, the surgeons performed the parasternal block and local anesthetic infiltration of sternotomy and tube sites with either 54 mL of saline placebo or 54 mL of 0.25% levobupivacaine with 1:400,000 epinephrine. Effects on pain and respiratory function were studied over 24 h. Patients in the levobupivacaine group used significantly less morphine in the first 4 h after surgery (20.8 +/- 6.2 mg versus 33.2 +/- 10.9 mg in the placebo group; P=0.013); they also had better oxygenation at the time of extubation. Four of nine in the placebo group needed rescue pain medication, versus none of eight in the levobupivacaine group (P=0.08). Peak serum levobupivacaine concentrations were below potentially toxic levels in all patients (0.64 +/- 0.43 microg/mL; range, 0.24-1.64 microg/mL). Parasternal block and local anesthetic infiltration of the sternotomy wound and mediastinal tube sites with levobupivacaine can be a useful analgesic adjunct for patients who are expected to undergo early tracheal extubation after cardiac surgery.

[Anaesthesia and intensive care for cardiac surgery in France: results of the three days national survey realised in 2001 by the club of Anaesthesia, Intensive Care and Technics in Cardiac Surgery (ARTECC)]

OBJECTIVES

Ageing of the surgical population and the evolution in anaesthetic techniques have led the Club d'anesthésie-réanimation et techniques en chirurgie cardiaque (ARTECC) to conduct a survey among French cardiac surgery centers. The aim was to profile patient population undergoing cardiac surgery and perioperative techniques employed.

STUDY

National prospective study including all adult patients undergoing cardiac surgery on January 23rd, 24th and 25th, 2001. Data were collected during the first 48 postoperative hours.

MATERIAL AND METHODS

Seven referent centers drafted a record form. Sixty-one centers sent back 425 patient forms, 399 were analyzed. The following were statistically studied: type of surgery, patient characteristics, preoperative treatment, monitoring, anaesthesia, cardio-pulmonary bypass (CPB) characteristics, duration of mechanical ventilation, length of stay in intensive care unit, postoperative complications.

RESULTS

Patient mean age was 64.3 +/- 13.3 years. Patients over 80-year-old represented 2.5% of the population. Beating heart coronary aortic bypass grafts (13% surgery) and preoperative transoesophagal echography were not frequent. Propofol and sufentanil were the main anaesthetic agents used. There was a marked trend for fast-track procedures.

CONCLUSIONS

The ARTECC study pointed out some reserve in practices and that the impact of new techniques seems limited. Regular use of studies of that kind will provide an effective tool to compare national practices.

Time to tracheal extubation after coronary artery surgery with isoflurane, sevoflurane, or target-controlled propofol anesthesia: A prospective, randomized, controlled trial

OBJECTIVES

To determine if anesthesia with sevoflurane or target-controlled propofol reduced the time to tracheal extubation after coronary artery bypass graft surgery compared with isoflurane anesthesia.

DESIGN

A 3-arm (isoflurane, sevoflurane, or propofol), randomized, controlled trial with patients and intensive care staff blinded to the drug allocation.

SETTING

A single, tertiary referral hospital affiliated with the University of Melbourne.

PARTICIPANTS

Three hundred sixty elective coronary artery surgery patients.

INTERVENTIONS

Patients received either isoflurane (control group, 0.5%-2% end-tidal concentration), sevoflurane (1%-4% end-tidal concentration), or target-controlled infusion of propofol (1-8 microg/mL plasma target concentration) as part of a balanced, standardized anesthetic technique including 15 microg/kg of fentanyl.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was time to tracheal extubation. The median time to tracheal extubation for the propofol group was 10.25 hours (interquartile range [IQR] 8.08-12.75), the sevoflurane group 9.17 hours (IQR 6.25-11.25), and the isoflurane group 7.67 hours (IQR 6.25-9.42). Intraoperatively, the propofol group required less vasopressor (p = 0.002) and more vasodilator therapy (nitroglycerin p = 0.01, nitroprusside p = 0.002). There was no difference among the groups in time to intensive care unit discharge.

CONCLUSIONS

The median time to tracheal extubation was significantly longer for the target-controlled propofol group. A significantly greater number in this group required the use of a vasodilator to control intraoperative hypertension.

Evidence-based practice - an incomplete model of the relationship between theory and professional work

RATIONALE, AIMS AND OBJECTIVES

Current day realities of diminishing resources, reductions in spending and organizational change within health care systems have resulted in an increased emphasis on a multidisciplinary team approach to quality patient care. The movement of nursing towards more autonomous practice combined with the current trend towards 'evidence-based practice' in health care demands increased accountability in clinical decision making. This paper focuses on one aspect of nurses' clinical decision making within the demands of evidence-based practice and cardiac surgery. In this field recent advances, combined with increasing demands on health care institutions, have promoted early extubation of post-operative cardiac patients. While this remains a medical role in many institutions, an increasing number of intensive care units now consider it as a nursing role.

METHOD

This paper explores the realities of nurses' clinical decision making through a discussion of current practice in the extubation of patients following cardiac surgery. In addition, it considers the implications of current practice for both nurse education and the continued development of clinical nursing practice.

CONCLUSION

The findings indicate that evidence-based practice appears to be an incomplete model of the relationship between theory and professional work.