Felix Ramon Montes, MD

PRO:

Recent changes in health care have focused attention on cost. This attention has motivated clinicians and hospitals administrators to develop and implement strategies to contain or reduce costs, particularly in high-cost areas such as cardiac surgery. One popular strategy known as the fast-track surgery pathway, uses modified anesthetic management that facilitates early extubation at 1 to 6 hours after surgery. This approach has proved to be safe and cost beneficial by reducing Intensive Care Unit stay and has been successfully adopted in many hospitals around the globe (1,2). An extension of this approach is immediate tracheal extubation after cardiac surgery.

In spite of reports of favorable outcome with this technique, it has not been universally adopted. Lichtenthal (3), Hutter (4), Turfrey (5), Jindani (6) and Royse (7) described the safe management of a large number of cardiac patients extubated in the operating room after uncomplicated cardiac surgery. Common in those studies was the use of limited doses of opioids, inhalational anesthesia for maintenance, use of non-narcotic analgesia, and a great deal of attention to temperature control and postoperative sedation. In the studies there were no detectable adverse effects attributable to earlier extubation and it did not result in an increase in postoperative morbidity. Opponents to immediate extubation argue that extubation in the operating room can augment respiratory and cardiac workload, and potentially increase the incidence of postoperative ischemia and myocardial infarction. To date, no study has demonstrated a statistically higher incidence of myocardial infarction in patients extubated in the operating room. In those studies the incidence of myocardial infarction and cardiac complications, including mortality was not different than the individual normally expected at centers (3-8).

The rate of reintubation has varied from 0% in the study of Royse (7) up to 8% in the study of Montes et al (8). This complication should not be viewed as a failure but as a possibility when a more liberal tracheal extubation criteria is used. Need for reintubatuion could be explained in part by the anesthesia technique or most importantly, by the anesthesiologist´s learning curve. We believe that reintubation per se does not have a deleterious effect in the general status of the patient, and that it is not associated with an adverse outcome if expert personnel perform the procedure.

Some authors believe that tracheal extubation in the operating room causes a delay in the operating room and would increase the operating room cost. No study has shown that this practice does significantly increase these variables because in general, the patient is promptly evaluated, and the patient who does not meet the extubation criteria for any reason (i.e. neurologic deficit) is transferred to the intensive care unit where his treatment is continued. It is important to point out that extubation in the operating room does not necessarily result in a significantly shorter intensive care unit or hospital stay. The cost reductions that could be achieved with that practice, depends on the particular hospital and the method to deliver postoperative care.

Operating room extubation has been disregarded as an option in uncomplicated cardiac surgery, based on no evidence. The timing of extubation postoperatively depends on both medical and "cultural" practices. Apart from medical consider-ations, there may be entrenched or cultural factors that may lead anesthesiologists and ICU staff to resist immediate tracheal extubation.

References

1. Westaby S, Pillai a, O'Regan D, Giannopoulos K, et al. Does modern cardiac surgery require conventional intensive care? Eur J Cardiothorac Surg 1993; 7: 313-18

2. Cheng DCH, Karski J, Peniston C, Asokumar B. Morbidity outcome in early versus conventional tracheal extubation after coronary artery bypass surgery: a prospective randomized controlled trial. J Thorac Cardiovasc Surg 1996; 112: 755-64

3. Lichtenthal PR, Wade LD, Niemyski PR, Shapiro BA. Respiratory management after cardiac surgery with inhalational anesthesia. Crit Care Med 1983; 11: 603-5

4. Hutter JA, Aps C, Hernsi D, Williams BT. The management of cardiac surgical patients in a general surgical recovery ward. J Cardiovasc Surg (Torino) 1989; 30: 273-6

5. Turfrey DJ, Ray DA, Sutcliffe NP, Ramayya P, et al. Thoracic epidural anaesthesia for coronary artery bypass graft surgery. Effects on postoperative complications. Anaesthesia 1997; 52: 1090-5

6. Jindani A, Aps C, Neville E, Sonmez B, et al. Postoperative cardiac surgical care: an alternative approach. Br Heart J 1993; 69: 59-63

7. Royse CF, Royse AC, Soeding PF. Routine immediate extubation after cardiac operation: a review of our first 100 patients. Ann Thorac Surg 1999;68:1326-9

8. Montes FR, Sanchez SI, Giraldo JC, Rincon JD, et al. The lack of benefit of tracheal extubation in the operating room after coronary artery bypass surgery. Anesth Analg 2000; 91: 776-80

Felix Ramon Montes, MD
Department of Anesthesiology
Fundacion Cardio-Infantil
Universidad del Rosario
Bogota, Colombia

CON:

Cost containment issues in the 1990's have promoted the implementation of fast-track cardiac surgery programs. A perioperative anesthetic management that facilitates early tracheal extubation is a key element of this process. (1,2) Early extubation following cardiac surgery has been possible with the use of short-acting drugs and reduced doses of narcotics, improved surgical techniques and myocardial protection, postoperative analgesia, and a paradigm shift in postoperative cardiac surgical care with the establishment of Intensive Care Units (ICU) with dedicated medical teams and flexible clinical pathways. Early extubation, i.e. when performed within 1-6 hours after arrival to the ICU, does not increase postoperative cardiorespiratory morbidity, sympathoadrenal stress or mortality, and significantly reduces costs and improves resource utilization. (3,4) Fast-track intraoperative management allows extubation in the Operative Room (OR) possible for the majority of patients, (5-7) but we must consider the potential benefits and disadvantages associated with this practice. (8,9)

Potential Benefits

Advocates of immediate extubation in the operating room following cardiac surgery claim a reduction in perioperative costs related to the avoidance of the use of a ventilator in the ICU, as well as the possibility of patients being transferred to an intermediate-level observation area, completely bypassing the ICU. (5,7,9) However, the cost of respiratory therapy services and ventilator use postoperatively accounted for less than 0.1% of the total charges. (3) It is unlikely that the services of a respiratory therapist can be completely avoided with extubation in the OR, making these savings even lower.

The establishment of a Cardiac Recovery Area has allowed uncomplicated patients to be recovered in a less expensive setting than an ICU. (5,7,9) But we need to analyze if we are indeed saving resources and not shifting the cost of care to a different service. The concept of providing graded levels of care for post cardiac surgery patients can be categorized by patient flow and postoperative recovery (10): (I) Conventional Model: usual flow of patients from the OR to the ICU, and then to a free standing unit and ward. (II) Parallel Model: there is a free standing unit that admits less severely ill postoperative cardiac patients and functions in parallel to an independent ICU. (III) Integrated Model: this is a fully integrated ICU that admits all postoperative patients, then recovers them with flexible nursing ratios for different acuity levels. Because nursing staff salaries represent the major cost in any ICU or intermediate care area, flexibility in nurse scheduling is a prerequisite for efficient resource utilization. A parallel model will decrease costs only if its nursing staff can adapt to variations in workload, by either sharing personnel between units or by having a pool of part-time nurses to complement the scheduled ones. Furthermore, it involves a capital and staffing investment to set up a duplicated intermediate unit separate from the pre-existing ICU. In the integrated model with a properly working fast-track cardiac surgery program, uncomplicated patients are quickly extubated and their acuity level reduced, with the consequent lower nurse to patient ratio and better resource utilization. The flexibility of nurse scheduling in this integrated system allows maximum cost savings, and this lowers the service workload cost per patient. (3,11) A parallel system lacks predictability, and the unexpected ICU admission could force the cancellation of elective cases.

In a recent study of 100 consecutive CABG patients enrolled in a fast track cardiac surgery pathway, (6) fifty percent of patients were extubated in the OR (median time, 15 min) and 50% of patients were extubated in the ICU (median time 182 min). This study reaffirms that OR extubation is possible in selected CABG patients, but a moderate rate of morbidity such as reintubation should be expected. No improvement in ICU or hospital LOS was found. The authors concluded that OR extubation did not provide any benefit when compared to extubation in the ICU 1-6 hr later.

Disadvantages

OR time is the most expensive direct variable cost of CABG surgery (3), and attempting to extubate a post-cardiac surgery patient in the OR undoubtedly increases OR time and delays turnover. This may increase OR nursing overtime costs and results in the cancellation of subsequent cardiac cases. This would easily negate any potential savings associated with decreased ventilator use in the ICU.

Extubation in the OR may increase respiratory and cardiac workload and potentially increase the incidence of cardiorespiratory complications such as myocardial ischemia, tracheal re-intubation, hypothermia, shivering, inadequate analgesia, and mortality. Most cardiac events resulting from perioperative myocardial ischemia or infarction, or inadequate myocardial protection during CPB, will manifest within the first postoperative hour. Before extubation, a period of observation with hemodynamic monitoring in an ICU setting should detect which patients will need intensive postoperative hemodynamic support. It has been demonstrated that the first hour after extubation is most crucial in respiratory care, as reflected by the apnea index and the return to baseline of the tidal volume. (6) Weaning should start only when gas exchange has been confirmed to be adequate and pain is well controlled. Premature extubation in the OR may increase respiratory morbidity in these patients. However, early tracheal extubation (1 to 6 hours) after CABG has been demonstrated not to increase perioperative cardiac or respiratory morbidity, and to be well tolerated by the nursing staff recovering these patients. (4)

Excessive mediastinal bleeding requiring re-exploration is a potential problem in any cardiac surgical patient. The incidence after CABG surgery varies from 1.5 _ 3% (12,13), and may be higher in centers where surgeons are being trained. Concealed bleeding may lead to cardiac tamponade and catastrophic cardiovascular collapse, requiring emergent reopening of the chest. (14) A secured airway is obviously desirable in these circumstances.

Thermoregulation is impaired during anesthesia for cardiac surgery. Despite adequate rewarming, core temperature decreases after the operation ("afterdrop") due to persistent temperature gradients between the core and the periphery. (15)

Postoperative hypothermia increases morbidity and can cause shivering, which leads to increased metabolic rate and potentially to myocardial ischemia. (16)

Central nervous system dysfunction is an unavoidable complication following cardiac surgery. The incidence of focal neurologic events is reported to be between 0.4 and 9%, with a strong correlation to age (less than 1% for patients under 65 years, 7 to 9 % in patients over 75 years). (17,18) Patients suffering a neurologic event have a ninefold increase in mortality (18), and often need increased respiratory care and longer ventilatory support. Extubation in the OR precludes the critical period of observation required to diagnose and assess the severity of the deficit, thus increasing the risks of aspiration and other respiratory complications.

Risk factors for delayed extubation following CABG surgery have been identified (19). These include increased age, female gender, intra-aortic balloon pump or inotrope use postoperatively, bleeding and atrial arrhythmia. Risk factors for prolonged ICU LOS include the above mentioned in addition to preoperative myocardial infarction and postoperative renal insufficiency.

Furthermore, practical issues that would need to be addressed are: How do we pre-select the patients to be extubated in the OR? For how long can we afford to delay the OR turnover just to ensure that these patients are safely extubated? What would the process of postoperative care be if these patients could not be extubated as planned? Do we keep two sets of nursing staff in the ICU and PACU? Which service decides on the admission policy for these patients?

During the last several years new surgical techniques have been developed that allow certain cardiac surgical procedures to be performed through smaller incisions and sometimes without CPB (20). The use of off-pump coronary artery bypass surgery (OPCAB) is increasing rapidly, and with the combined use of regional anesthesia this technique could potentially allow certain patients to be extubated in the OR. But to date there is no published long-term, prospective, randomized study indicating that OPCAB with ultra-fast tracking is either safe or cost-effective in comparison to on-pump CABG surgery.

Conclusion

Fast-track cardiac surgery programs have been established as the standard of cardiac surgical care. Early tracheal extubation (i.e., between 1 _ 6 hours after arrival to the ICU) is a key element of this process, and has been proven to be safe and cost-effective. In controlling costs, we must understand the different components of the total cost of care, and focus our efforts appropriately. The economic consequences of post-CABG complications are far more costly than an uncomplicated recovery. It is more important to optimize the postoperative process of care than to create potential risks by extubating these patients on the OR table. The risks of pushing the limit to extubate on-pump CABG patients in the OR outweigh the potential marginal gain.

References

1. Cheng DCH: Fast Track Cardiac Surgery Pathways: Early Extubation, Process of Care, and Cost Containment. Editorial: Anesthesiology 1998; 88:1429-1433

2. Cheng DCH. Anesthetic techniques and early extubation: does it matter? J Cardiothorac Vasc Anesth 2000; 14: 627-30

3. Cheng DCH, Karski J, Peniston C, et al: Early Tracheal Extubation after Coronary Artery Bypass Surgery Reduces Costs and Improves Resource Use: A Prospective, Randomized, Controlled Trial. Anesthesiology 1996; 85:1300-1310

4. Cheng DCH, Karski J, Peniston C, et al: Morbidity outcome in early versus conventional tracheal extubation after coronary artery bypass grafting: a prospective randomized controlled trial. J Thorac Cardiovasc Surg 1996; 112:755-764

5. Royse CF, Royse AG, Soeding PF: Routine immediate extubation after cardiac operation: A review of our first 100 patients. Ann Thorac Surg 1999; 68:1326-1329

6. Montes FR, Sanchez SI, Giraldo JC, et al: The lack of benefit of tracheal extubation in the operating room after coronary artery bypass surgery. Anesth Analg 91: 776-80, 2000

7. Westaby S, Pillai R, Parry A: Does modern cardiac surgery require conventional intensive care? Eur J Cardiothorac Surg 1993; 7:313-318

8. Peragallo RA, Cheng DCH: Con: Tracheal extubation should not occur routinely in the operating room after cardiac surgery. J Cardiothorac Vasc Anesth 2000; 14: 611-13 9. Lee TWR, Jacobsohn E: Pro: Tracheal extubation should occur routinely in the operating room after cardiac surgery. J Cardiothorac Vasc Anesth 2000; 14: 611-13

10. Cheng DCH, Byrick RJ, Knobel E: Structural models for intermediate care areas. Crit Care Med 1999; 27:2266-2271

11. Cheng DCH: Does early extubation of coronary artery bypass graft surgery patients truly decrease perioperative costs? Appropriate analysis of direct variable costs. Anesthesiology 1997; 87:182

12. Cheng DCH, David TE: Perioperative Care in Cardiac Anesthesia and Surgery. Austin, TX, Landes, 1999, pp 2

13. Munoz JJ, Birkmeyer NJO, Dacey LJ, et al: Trends in rates of reexploration for hemorrhage after coronary artery bypass surgery. Ann Thorac Surg 1999; 68:1321-1325

14. Yau TM: Chest Reopening, in Cheng DCH, David TE (ed): Perioperative Care in Cardiac Anesthesia and Surgery. Austin, TX, Landes, 1999, pp 201-206

15. Leslie K, Sessler DI: The Implications of Hypothermia for Early Tracheal Extubation Following Cardiac Surgery. J Cardiothorac Vasc Anesth 1998; 12:30-34

16. Frank S, Beattie C, Christopherson R, et al: Unintentional hypothermia is associated with postoperative myocardial ischemia. Anesthesiology 1993; 78:468-476

17. Gardner TJ, Horneffer PJ, Manolio RA, et al: Stroke following coronary artery bypass grafting: A ten-year study. Ann Thorac Surg 1985; 40:574-581

18. Tuman KJ, McCarthy RJ, Najafi H, Ivankovich AD: Differencial affects of advanced age on neurologic and cardiac risks of coronary artery operations. J Thorac Cardiovasc Surg 1992; 104:1510-1517

19. Wong DT, Cheng DC, Kustra R, et al: Risk factors of delayed extubation, prolonged length of stay in the intensive care unit, and mortality in patients undergoing coronary artery bypass graft with fast-track cardiac anesthesia: a new cardiac risk score. Anesthesiology 1999; 91:936-944

20. Acuff TE, Landreneau RI, Griffith SP, et al: Minimally invasive coronary artery bypass grafting. Ann Thorac Surg 1996; 61:135-137

Davy C. H. Cheng, MD, MSc, FRCPC
Toronto General Hospital
University of Toronto
Toronto, ON, Canada