Introduction

Fast-tracking is a form of care which encourages a rapid recovery from CABG and early discharge from the hospital in a medically safe and efficacious manner. Fast-tracking usually involves specific protocols or care maps which set expectations of care for the staff and define the procedures, laboratory tests and consultations which are appropriate and expected for a given day of hospitalization. Such a care map usually starts with intensive preoperative teaching about the hospitalization, what to expect and a statement of the care team’s objective to provide a short hospital stay for the patient. It is important to involve both the patient and the family in this education as it sets the foundation for an early discharge. This teaching may be done in the hospital for patients admitted the night before surgery, or may be done in the preoperative screening and testing area for same-day admitted CABG patients. Setting goals and realistic expectations for the patients, the patients’ families, the staff and the responsible physicians encourages a multidisciplinary effort to reduce hospital length of stay as well as reduce morbidity and associated hospital costs.

The second goal of FT is a safe and short cardiac operation using short-acting anesthetics. This involves short cross-clamp times, short cardiopulmonary bypass (CPB) times and warming patients at the end of surgery. It also requires that patients have minimal need for inotropic support and are provided with good analgesia to facilitate waking shortly after the operation. The next goal is a hemodynamically stable patient without bleeding who can undergo EE in the operating room (OR) or shortly after arrival to the intensive care unit (ICU). Early extubation has been discussed in the literature since the late 1970s and 1980s but has only been effectively and widely implemented in the 1990s [1-3]. Stated advantages include shorter ICU stays with less need for mechanical ventilation (less risk of pneumonia, fewer arterial blood gas analyses, less risk of endotracheal tube and ventilator malfunction), greater patient comfort in the ICU, and decreased intrapleural pressures with resultant improvement in ventricular filling and cardiac output [4]. Early extubation allows for a shorter ICU stay with, perhaps, fewer respiratory system disturbances (such as less atelectasis), less significant decreases in spirometric values (FEV1, FVC, FEV1/FVC ratio) [5] and improved intrapulmonary shunt fraction [6]. In a more aggressive protocol, some have advocated for EE with subsequent step-down unit care and not ICU care for CABG patients [7]. Others have stated that EE and FT are not goals to be pursued at all [8].

Postoperatively, once the patient is on the ward, management goals include early mobilization (out of bed on day 1, walking on day 2 and perhaps stairs on day 3), adequate analgesia without sedation, early return of bowel function (using agents such as metaclopramide, docusate, ranitidine) and further education of the patient and family with respect to cardiac rehabilitation, diet and activity recommendations. The ultimate goal is discharge of the patient within 3 to 5 days following CABG.

Clearly, EE and FT practices are, at least in part, economically driven. One study examined the costs of FT versus non-FT CABG patients [9]. The FT patients had a 6 day LOS and incurred approximately $12, 400 in costs, whereas the non-FT patients had an 8.2 day LOS and incurred approximately $18,400 in costs. In a separate cost analysis, another group found a difference of approximately $2,000 in total hospital costs between patients managed with EE versus conventional extubation [10].

LOS and Predictive Factors

Many investigators have examined LOS with respect to identification of predictive factors for LOS. Preoperative and postoperative factors have been identified which correlated with a LOS >7 days [11]. These factors included redoing surgery, combined CABG and valve surgery, congestive heart failure (CHF), preoperative ICU stay, renal failure, insulin-dependent diabetes (IDDM) (but not non-insulin-dependent diabetes) [12]. Postoperative risk factors included development of arrhythmia, respiratory insufficiency, pneumonia, and wound infection. Others have proposed further risk factors for prediction of perioperative morbidity and LOS >12 days [13]. One group found the following risk factors: emergency surgery, IDDM, arrhythmia, ejection fraction (EF) <49%, cerebrovascular disease, and obesity. In another paper, it was stated that EF was not a predictor of LOS but was a predictor for resource utilization [14]. The development of atrial fibrillation (AF) also increases ICU stay, hospital LOS and hospital costs [15-17]. Others have also suggested that transaminase levels after surgery, pneumo- or hydrothorax development after surgery and number of cerebral emboli all predicted greater LOS [18, 19].

The point of examining the perioperative predictive factors for LOS is so that patients can be identified as being at higher risk for longer LOS and interventions can be made to modify these risk factors. Further interventions that have been suggested for success in FT include: aggressive use of preoperative intraaortic balloon pump (although this has also been identified as a risk factor for a longer LOS), use of intraoperative steroids, use of half-dose aprotinin [20], achieving a postoperative negative fluid balance, prevention and treatment of atrial fibrillation, and administration of thyroid hormone [21].

Length of stay outcomes have also been examined. Many investigators have found no difference or less occurrence of cardiac morbidity and perioperative complications in early discharge patients [6,22]. Further, many have found no differences in 30 day morbidity or mortality [23].

Another group stated that complex patients can be fast-tracked if one sets the goal and works to meet it [24]. They examined two groups of patients: those intended for FT preoperatively and those not intended for FT (non-FT). The FT group had 48% discharge by day 3-5, with 77% patient satisfaction. The non-FT group had 26% discharge at day 3-5, with 54% patient satisfaction. There was no difference in infection, operative mortality, and 30-day readmission rates. Others examined patients with poor left ventricular function and found that when FT goals were set for these patients, approximately 50% were able to be extubated within 6 hours, discharged from the ICU on postoperative day (POD) 1, and discharged from the hospital by POD 5. No adverse effects were attributed to FT pathway expectations. Others have tried to mimic the success of minimally invasive surgery with aggressive FT protocols. They state that the success with decreased LOS in "off-pump" cases can be achieved in "on-pump" CABG cases with an aggressive FT protocol and with the goal of a 3-day discharge [25].

The role of the anesthesiologist is important to EE, which in and of itself contributes to decreases in LOS [26]. One needs to have a warm patient, who is potentially extubatable by 0-6 hours postoperatively. Thus, the patient should have adequate analgesia (fentanyl, morphine, and intrathecal narcotics have all been used) [27], be able to spontaneously breathe (neuromuscular blockade (NMB) gone or reversed), be hemodynamically stable, and have adequate oxygenation. One study stated that the type of NMB agent used did not affect the ICU LOS after tracheal extubation [28]. Thus, how one uses NMB agents, and not which agent one uses, is important. In this study, use of a short-acting opioid was associated with earlier extubation but no difference in ICU LOS. Others have found that intraoperative clinical variables affect the time to extubation (not all of which are under the control of the anesthesiologist) [29]. These included age, sufentanil dose, major inotrope use, platelet transfusion, use of an arterial graft, and fentanyl dose.

CABG in the Elderly

As our population ages, more patients are presenting for cardiac surgery at an advanced age. As FT has been found to be successful in decreasing ICU LOS, hospital LOS and hospital costs without increased morbidity and mortality, the question has been asked about whether this approach can be used in the elderly patient. In 1996, one group found that ninety-year-old patients had a mean LOS of 26 days with an acceptable morbidity and mortality rate and concluded that cardiac surgery was justifiable in this age group [30]. Others found that cardiac operations can also be successful in most 80-year-old patients, but with increased mortality, stroke and longer LOS (31-51% having LOS >14 days) [31]. Another group examined the impact of an EE and FT protocol in elderly patients [32]. They found that 48% of the elderly vs. 59% of the younger patients met the goal of extubation within 8 hours. Of those extubated within 8 hours, the younger group had a mean LOS of 5.5 days and the elderly had a mean LOS of 8.4 days. They concluded that the elderly have more comorbid conditions, but that a significant number could still follow an EE and FT protocol safely. In a similar study it was found that 19% of elderly patients, compared to 48% of younger patients, met the goal of discharge by POD 5 and that on average younger patients had a LOS of 5.7 days vs. 8 days for older patients [33]. There were no differences in 30-day mortality rates or postoperative complications between the elderly and younger groups. Using a rapid recovery protocol, one group achieved a 71% discharge rate by POD 10 in octogenarians [34]. Clearly, elderly patients have longer LOS than younger patients but can still benefit from EE and FT protocols. It has also been suggested that interventions designed to reduce preoperative CHF and aggressively treat other comorbidities may also improve elderly patients’ recovery and reduce costs [35].

Role of Minimally Invasive Cardiac Surgery

Minimally invasive cardiac surgery has been touted to reduce hospital LOS and costs, and many studies have explored this theory. The main issue with minimally invasive cardiac surgery is how many vessels can be done during an operation and what the long-term patency rates are compared to conventional CABG. The answers to these questions are not yet entirely known. Most studies have examined minimally invasive direct coronary artery bypass (MIDCAB) or "off-pump" CABG. Several groups have found low LOS for patients undergoing MIDCAB, with LOS ranging from 2.7 to 5.9 days and good postoperative patency rates [36-41]. Some studies have compared MIDCAB with conventional CABG using CPB and percutaneous coronary angioplasty (PTCA). One group found a 2.7 day and 2.6 day LOS for MIDCAB and PTCA patients, respectively, as compared to a 4.8 day LOS for conventional CABG [42]. Further, MIDCAB and later PTCA have been combined for a reported 5.9 day LOS [43]. MIDCAB is being used more frequently in higher risk patients and in cases of multivessel disease with good patency results [44].

In summary, EE and FT are viable methods for encouraging safe, efficacious and expedient care of the patient presenting for cardiac surgery. The factors affecting LOS, use of these protocols in the elderly and the role of minimally invasive surgery have been fairly well studied, as discussed above.