Asian Cardiovasc Thorac Ann 2007;15:144-148
© 2007 Asia Publishing EXchange Ltd
Influence of Fast-Track Recovery after Coronary Artery Bypass in the Elderly
Nicholas Charokopos, MD,
Polychronis Antonitsis, MD,
Michalis Toumbouras, MD,
John Konstantinopoulos, MD,
Efthymia Rouska, MD
First Department of Thoracic and Cardiovascular Surgery, Aristotle University of Thessaloniki, AHEPA University Hospital, Thessaloniki, Greece
For reprint information contact: Nicholas Charokopos, MD Tel: 30 23 1034 0034 Fax: 30 23 1099 4871 Email: charokoposnick{at}hotmail.com, 22, Grigoriou E’ St., Panorama, 55 236 Thessaloniki, Greece.
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ABSTRACT
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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 (
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 5th 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.
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INTRODUCTION
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Clinical rapid recovery protocols, so-called "fast-track" protocols, based on early extubation and fast-track treatment of cardiac surgical patients, are being increasingly incorporated by cardiac surgery centers worldwide.1,2 Early reports excluded elderly patients (> 70 years) from these protocols because they represent increased operative risk.3 However, recent reports of encouraging results of fast-track treatment in an elderly population stimulated us to apply a rapid recovery protocol, with some modifications, to a consecutive series of patients undergoing isolated coronary artery bypass grafting (CABG).4–6 Results in un-selected elderly (70 years) patients were compared with those of the younger (< 70 years) population.
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PATIENTS AND METHODS
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Approval for this study was obtained from our institutional review board. From January 2000 to December 2004, 711 consecutive patients underwent isolated CABG under cardiopulmonary bypass (CPB). Their data were reviewed retrospectively. All patients were treated comparably by the same team of surgeons. There were 531 males and 180 females. Their median age was 61.3 years (range, 50–79 years); 572 (80%) patients were less than 70 years of age, and 139 (20%) were aged 70 years or older. Patients who had minimally invasive CABG without CPB were excluded from this study.
The fast-track recovery program consisted of an anesthetic protocol for early extubation, reduced CPB time, early identification and management of postoperative atrial fibrillation, proactive maintenance of a negative fluid balance, rapid return of bowel function, mobilization of the patient, and aggressive use of an intra-aortic balloon pump preoperatively.1 For the purpose of this study, early extubation was defined as removal of the endotracheal tube within 8 hr of arrival in the surgical intensive care unit (ICU), as used in previous reports.7 Operative death was defined as death occurring within 30 days of operation or during the same hospital stay. The anesthesia was standardized and consisted of increased use of inhalational agents and propofol, and decreased dosages of narcotics. Anesthesia was induced with intravenous fentanyl (10–15 µg ·kg–1), midazolam (15 µg ·kg–1), and vecuronium bromide (0.1 mg ·kg–1). All of the fentanyl was administered before sternotomy. Approximately 70% of the calculated midazolam dose was administered before sternotomy, and the balance was given during rewarming. Anesthesia was maintained during the operation with midazolam (0.05 mg ·kg–1), pancuronium (0.1 mg ·kg–1) and propofol (1.5 to 2.0 mg ·kg–1) as a continuous drip. Propofol was discontinued postoperatively within 4 hr, provided that the patient was hemodynamically stable without surgical bleeding.
Operative techniques included standard CPB with a membrane oxygenator and normothermia. Myocardial preservation was undertaken in all cases with potassium crystalloid cardioplegia (St. Thomas’ Hospital solution) delivered by an antegrade technique into the aortic root. The temperature was allowed to drift to 34°C–32°C routinely; active cooling to a lower temperature was reserved for complex reconstructions. Early initiation of CPB occurred only in the case of hemodynamic instability or in re-operations when decompression of the heart further aided dissection. Each distal anastomosis was performed after cardioplegic arrest. Conduits for myocardial revascularization were the left internal thoracic artery and saphenous vein exclusively. On completion of each distal anastomosis, additional warm blood cardioplegia was delivered through each vein graft. On completion of all distal anastomoses, the aortic cross clamp was released and the proximal anastomoses were completed under partial aortic occlusion. Patients were transferred to the ICU where postoperative care was standardized, and tracheal extubation was accomplished at the earliest clinically appropriate time by the anesthesiologist or the cardiothoracic resident on-call. Criteria for extubation in our ICU included: patient responsive and cooperative, vital capacity > 10 mL ·kg–1, arterial oxygen tension > 80 mm Hg, fraction of inspired O2 < 0.50, cardiac index > 2.0 L ·min–1 ·m–2, oropharyngeal temperature > 36.0°C, pH > 7.30, chest tube drainage < 100 mL ·hr–1 in the previous 2 hr, and absence of uncontrolled arrhythmia. Active diuresis was started within 24 hr with the use of loop diuretics to establish an early negative fluid balance. All patients without evidence of conduction abnormalities were given digitalis postoperatively. Frequent premature atrial contractions or new-onset atrial fibrillation were treated with an intravenous loading dose of 1,250 mg of amiodarone, followed by continuous infusion of a solution of amiodarone 600 mg in 250 mL at 50–70 mL ·hr–1. After chemical conversion, oral amiodarone 200 mg 3-times daily was administered for a period of 4 weeks. After early extubation, a vigorous rehabilitation program was started the day after the operation. Ambulation began at 36 hr postoperatively under the supervision of a physiotherapist. Rapid convalescence was emphasized, and progress was assessed regularly by the surgeon and clinical specialists.
Results are expressed as mean ± standard deviation or as percentages. Clinical and operative differences between the two groups were tested for statistical significance using the t test, whereas differences in percentages were tested with the chi-squared test.
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RESULTS
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Preoperative patient characteristics are shown in Table 1
. The elderly group represented higher-risk patients with a greater proportion of women, more congestive heart failure, and a less favorable EuroSCORE. The 30-day mortality rate for the entire series was 3.5% (25/711 patients). There was no significant difference in 30-day mortality between the two groups. The operative variables are listed in Table 2. Elderly patients required slightly fewer bypass grafts and consequently had a shorter duration of operation than the younger patients. Table 3 compares the postoperative complications between the age groups. There was no significant difference in the number of postoperative complications between the two groups. The postoperative patient data described in Table 4 helps define the effect of our fast-track approach. The impact of age in 469 of 711 patients who were extubated within 8 hr is depicted in Figure 1. Early extubation declined with increasing age. Nonetheless, more than half of the patients over 70-years old were extubated early. The main factors that contributed to failure of early extubation in both groups were postoperative complications, such as hemodynamic instability that required use of an intra-aortic balloon pump and increased doses of inotropics, excessive bleeding (> 300 mL ·hr–1), and atrial or ventricular arrhythmias.
Reintubation rates were negligible in both groups. Early discharge at 5 days was achieved in 48% of younger patients (263/553) and 19% of the elderly (25/133; p < 0.001). This had no significant adverse effect on the incidence of any complications, such as arrhythmias, infection, or mortality. The frequency of hospital readmission within 30 days was 7% (39/553) for the younger group and 8% (11/133) for the elderly patients. The reasons for readmission were many; the most frequent being treatment of pleural effusion, recurrent chest pain, wound infection, congestive heart failure, and adjustment of medications. Remarkably, therapy for arrhythmia management was not a frequent reason for readmission. In the analysis of reasons for readmission, there were no significant differences between the groups, and the numbers were very small.
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DISCUSSION
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Although much is known about the efficacy of fast-track treatment protocols on outcomes among young patients, the success of such protocols when applied to the older high-risk population has not been thoroughly validated.8 In this study, we demonstrated that current techniques that emphasize the use of low-dose opiate balanced anesthesia permitting early extubation, and a surgical approach that promotes a reduction of operative time, can be applied to older patients undergoing CABG, with promising results. The elderly are generally more sensitive to drugs that depress the central nervous system. As a result, these drugs should be administered in reduced dosages. Since the elimination half-lives of fentanyl and midazolam are prolonged 3 to 4 times in the elderly, the doses were reduced by approximately 50%.7,9 Early extubation continues to be a dynamic process, and although more than half of the elderly patients in this study were extubated early, we believe that with further refinements of dosages among elderly patients, a higher percentage can be extubated early. According to Cheng and colleagues,10 fast-track anesthesia is safe and does not increase perioperative morbidity. There is an improvement in postextubation intrapulmonary shunt fraction and reduced ICU and hospital lengths of stay. Due to the known cost benefits of fast-track protocols combined with concomitant changes in operating room scheduling, there seems to be no compelling reason to use high-dose opioid regimens in anesthesia for elective cardiac surgery with CPB.
The negative circulatory effects on cardiac output of prolonged mechanical ventilation, positive-pressure ventilation, and positive end-expiratory pressure, are clearly documented and require extending the duration of ICU stay.10–13 There are convincing data that early extubation is not only feasible but preferable in most patients undergoing cardiac operations. The potential benefits of early extubation include improved ciliary function and earlier ability to cough.14,15 This was best shown by Westaby and colleagues16 whose early extubation protocol succeeded in accelerating recovery and minimizing ICU stay. Normothermic CPB is closer to the physiological circulatory situation of the whole patient and the heart than hypothermic CPB.6 In this study, all procedures were performed under normothermia. Cooling to temperatures lower than 34°C–32°C was not undertaken. With this approach, a perfusion temperature of 37°C was reached at the time of completion of the proximal anastomoses.
Prolonged CPB, particularly in the elderly, is frequently associated with dysfunction of various end organs. Postoperative renal insufficiency and prolonged mechanical ventilation secondary to pulmonary dysfunction are consequences of a prolonged operative procedure.17 It has therefore been advocated that every effort should be made to simplify the operation by reducing any steps that unnecessarily prolong operative time.2,5 Georghiou and colleagues18 reported earlier extubation rates with reduced CPB time. We aimed to make the best possible effort to reduce CPB time without compromising completeness of revascularization. All coronary arteries and their branches greater than 1.2 mm, which were jeopardized, were revascularized. The average number of bypass grafts in the younger group of patients was 3.2, compared to 2.9 in the elderly; these numbers are consistent with other series.5,19
In this study, postoperative morbidity was similar in both groups. Amongst our criteria for discharge we sought absence of pyrexia, but not stable sinus rhythm. Solomon and colleagues19 showed that patients with new-onset arrhythmia after CABG may be discharged in atrial fibrillation without any adverse morbidity in terms of readmission, thromboembolic or hemorrhagic events. The 10% overall incidence of new-onset atrial fibrillation in our series is comparable with other reports.5–7,20 Application of the fast-track protocol to elderly patients helped expedite recovery, but not to the same extent with respect to early extubation and short ICU stay as that achieved in younger patients. Despite the significant difference in comorbidities, 57% of elderly patients had early extubation and were discharged from the ICU the day after the operation. Failure of early extubation was mainly attributed to postoperative complications in our series. According to Wong and colleagues,12 perioperative variables were more closely associated with delayed extubation than preoperative variables alone. Thus, a fast-track protocol can be applied carefully and selectively in elderly patients who are hemodynamically stable and fulfill the early extubation criteria. Although younger patients were discharged from the ICU earlier than older patients, the elderly patients in this series had a very short hospital stay, which was comparable with other published series.2,5 The absence of any associated difference in morbidity or complication rates in elderly compared to younger patients clearly supports the benefits of applying fast-track treatment in the older population. Age should not be a determinant of the appropriateness of early extubation and subsequent fast-track recovery.
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ABSTRACT
INTRODUCTION
