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Early Extubation in Adults Undergoing Surgery for Congenital Heart Disease
ORIGINAL ARTICLES Early Extubation in Adults Undergoing Surgery for Congenital Heart Disease Constance G. Weismann, MD,* Shiayin F. Yang, BA,† Carol Bodian, DrPH,‡ Ingrid Hollinger, MD,‡ Khanh Nguyen, MD,§ and Alexander J.C. Mittnacht, MD‡ Objectives: Early extubation in adults undergoing surgery for congenital heart disease has not been described. The authors report their experience with extubation in the operating room (OR), including factors associated with the decision to defer extubation to a later time. Design: A retrospective chart review. Setting: A tertiary-care teaching hospital. Participants: This study included adults undergoing surgery for congenital heart disease using cardiopulmonary bypass. Exclusion criteria were as follows: preoperative mechanical ventilation, age >70 years, inotrope score >20 after surgery, and surgical risk (Risk Adjustment for Congenital Heart Surgery [RACHS] score >4). Interventions: A stepwise logistic regression model was used to test for the independent influence of the various factors on extubation in the OR. Measurements and Main Results: Sixty-seven patients (age 18-59 years, median ⴝ 32 years) were included. Overall,
79% of patients were extubated in the OR. The RACHS score was the strongest predictor of deferring extubation (RACHS 3 v 1 or 2: odds ratio ⴝ 16.7; 95% confidence interval, 3.384.2; p ⴝ 0.0006). Further exploration of the high-risk group (RACHS 3) showed that 75% of the RACHS 3 patients with a body mass index <25 were extubated compared with only 20% of patients who had a body mass index >25 (p ⴝ 0.01). Other factors included in the analysis did not contribute any additional independent information. Conclusions: Extubation of adult patients in the OR after surgery for congenital heart disease is feasible in most cases. Surgical risk (RACHS score) and body mass index predict the decision for OR extubation in this patient population. © 2012 Elsevier Inc. All rights reserved.
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all patients except those undergoing simple procedures had central venous access established before skin incision. A multiplane transesophageal echocardiographic probe (Siemens Medical Solutions USA, Inc, Malvern, PA) was inserted for intraoperative hemodynamic monitoring and to evaluate the surgical repair. After the administration of heparin (300 U/kg), the ascending aorta and inferior and superior vena cava were cannulated, and full CPB was established. A potent inhalation agent (eg, isoflurane or sevoflurane) was administered throughout the case including while the patient was on CPB. At the end of the surgical procedure, after the discontinuation of CPB, modified ultrafiltration was performed in all patients followed by heparin reversal with protamine based on a protamine-titration assay. The practice standard was to extubate all eligible patients in the OR. However, the final decision to attempt extubation in the OR was made by the attending surgeon and anesthesiologist at the end of the procedure. Patients were considered for extubation if they were hemodynamically stable without excessive inotropic support (total inotrope score ⱕ20 and epinephrine or norepinephrine each ⱕ0.05 g/kg/min), had a core body temperature ⬎35°C, had no signs of upper-airway edema, and showed no evidence of coagulopathy requiring continuous administration of blood products. In patients in whom these criteria were met, residual neuromuscular blockade was reversed with neostigmine and glycopyrrolate. Additional extubation criteria applied included the following parameters: an
HE NUMBER OF adult patients presenting for surgery for congenital heart disease (CHD) has increased.1,2 Although fast-tracking is practiced routinely in adult patients undergoing cardiac surgery not related to CHD,3 this approach is more controversial and has not been reported in adults undergoing surgery for CHD, and mechanical ventilation typically is continued postoperatively in the intensive care unit (ICU). At the authors’ institution, it has become routine practice to consider patients undergoing surgery for CHD for fast-tracking, including extubation in the operating room (OR). In this study, the authors report their experience with OR extubation in the adult CHD surgery patient population and discuss the factors associated with deferring extubation to a later time. METHODS After institutional review board approval, a retrospective database review of adult patients undergoing surgery for CHD at a tertiary-care teaching hospital between June 2003 and April 2009 was conducted. Inclusion criteria were as follows: patients ⱖ18 years of age and patients who had CHD surgery using cardiopulmonary bypass (CPB). Exclusion criteria were age ⬎70 years, surgery not requiring CPB, preoperative mechanical ventilation, thoracic organ transplantation, and a Risk Adjustment for Congenital Heart Surgery (RACHS)4 score ⱖ4. Excessive inotrope use after CPB is considered a contraindication for early extubation in the authors’ institution, and patients with an inotrope score ⬎205,6 also were excluded from the analyses. Anesthesia was induced with etomidate, 0.2 mg/kg, or propofol, 2 to 3 mg/kg intravenously, supplemented with fentanyl, 2 to 3 g/kg intravenously, and vecuronium, 0.1 mg/kg, for neuromuscular blockade and maintained with a potent volatile agent (isoflurane, sevoflurane, or desflurane) in air/oxygen. Unless contraindications applied, preservative-free morphine (7-10 g/kg) was administered intrathecally. Additional intravenous fentanyl was administered as needed and limited to a maximum cumulative dose of 5 g/kg. All patients had their arterial blood pressure monitored continuously with an indwelling catheter, and
KEY WORDS: congenital heart defects, cardiac surgery, fasttracking, cardiac anesthesia, ventilator, mechanical, intubation, tracheal, intensive care unit
From the *Division of Pediatric Cardiology, Yale University School of Medicine, New Haven, CT; †University of Toledo College of Medicine, Toledo, OH; and Departments of ‡Anesthesiology and §Cardiothoracic Surgery, The Mount Sinai School of Medicine, New York, NY. Address reprint requests to Alexander J.C. Mittnacht, MD, Department of Anesthesiology, The Mount Sinai Medical Center, Box 1010, One Gustave L Levy Place, New York, NY 10029. E-mail: [email protected] © 2012 Elsevier Inc. All rights reserved. 1053-0770/2605-0004$36.00/0 http://dx.doi.org/10.1053/j.jvca.2012.04.009
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adequate level of consciousness, intact protective airway reflexes, adequate pain control, arterial blood gas results indicating adequate oxygenation, and a tidal volume ⱖ6 mL/kg. Once the patient was breathing spontaneously with adequate respiratory parameters, the endotracheal tube was removed, and oxygen was administered via a nasal cannula. A continuous infusion of dexmedetomidine (0.4-0.8 g/kg/h) was started before transfer to the cardiac ICU, and intravenous fentanyl or morphine was given to patients with signs of inadequate analgesia. Patients in whom the attending anesthesiologist and surgeon made the decision not to proceed with extubation were transferred to the ICU intubated. The primary outcome was defined as deferring planned immediate OR extubation. Continuous variables were grouped, and each potential perioperative risk factor was screened individually to determine any association with not proceeding using the chi-square, Fisher exact, or the Cochran-Armitage test for trend as appropriate. Stepwise logistic regression was used to identify independent factors. When it became evident that almost all the patients with RACHS scores of 1 or 2 were extubated in the OR, the analyses were repeated for the subgroup of patients with an RACHS score of 3 alone. Characteristics of the patients with an RACHS score of 3 were compared with those of patients with an RACHS score of 1 or 2 using the Wilcoxon or chi-square tests. Statistical significance was defined as p ⬍ 0.05. The following perioperative factors were tested: age, body surface area, body mass index (BMI), sex, CPB time, aortic cross-clamp time, procedure length, anesthesia length, inotrope score, surgical risk (RACHS score), and prior cardiac surgery (reoperation). RESULTS
The chart review identified 72 patients who met the preoperative inclusion criteria. Five of these were excluded from the final analysis because of significant inotrope use after separation from CPB (inotrope score ⬎20). A total of 67 patients (age 18-59 years, median ⫽ 32 years) were included in the analysis. Overall, 79% (53/67) of patients were extubated at the end of the surgical procedure in the OR. Table 1 lists the type of
Table 1. Procedure Complexity, Cases/Procedures Performed, and the Patients Extubated in the OR RACHS
1 2
3
Case/Procedure
n
OR Extubation
ASD (secundum) ASD (sinus venosus) ASD (primum) VSD PVR RVOT reconstruction TOF Conduit revision Fontan TV repair Asc Ao/Ao root replacement AVR MV repair Unroofing of ACA DORV cAVC
16 4 4 5 9 2 1 5 3 6 4 1 4 1 1 1
16 4 3 5 8 2 1 3 2 2 2 0 2 1 1 1
Abbreviations: ASD, atrial septal defect; VSD, ventricular septal defect; PVR, pulmonary valve replacement; RVOT, right ventricular outflow tract; TOF, tetralogy of Fallot; TV, tricuspid valve; Asc, ascending; Ao, aorta; AVR, aortic valve replacement; MV, mitral valve; ACA, anomalous coronary artery; DORV, double-outlet right ventricle; cAVC, complete atrioventricular canal defect.
Table 2. Factors Included in the Analysis Factor
RACHS 1, 2 (n ⫽ 41)
RACHS 3 (n ⫽ 26)
p Value
Age BMI ⱖ25 (%) Men (%) Reoperation (%) Inotrope use (%) AoX time (min) CPB time (min) Procedure time (min) Anesthesia time (min)
32 (18-59) 21 (51) 17 (41) 11 (27) 6 (15) 17 (0-173) 66 (7-203) 224 (121-443) 339 (195-576)
23 (18-54) 10 (38) 17 (65) 15 (58) 17 (65) 91 (0-326) 162 (86-391) 356 (202-812) 467 (334-943)
0.05 0.31 0.06 0.01 ⬍0.0001 0.002 ⬍0.0001 ⬍0.0001 ⬍0.0001
NOTE. Data displayed as median (minimum, maximum) or number (%); p values included when groups were compared. Abbreviation: AoX, aortic cross-clamp.
cases/procedures performed, their RACHS classification, and the number of patients who were extubated in the OR. Logistic regression analysis of each factor on all 67 eligible patients revealed that surgical risk classified by the RACHS score was the strongest predictor of deferring endotracheal extubation (RACHS 3 v 1 or 2: odds ratio ⫽ 16.7; 95% confidence interval, 3.3-84.2, p ⫽ 0.0006). Further examination of the data found that patients who were classified as RACHS category 1 or 2 differed markedly from the RACHS category 3 patients in most factors under consideration. When compared with the RACHS 1 and 2 patients, patients in the RACHS 3 group were younger (p ⫽ 0.05); had longer CPB, aortic cross-clamp, procedure, and anesthesia times (p ⬍ 0.0001, p ⫽ 0.002, p ⱕ 0.0001, and p ⬍ 0.0001, respectively); and required more inotropic support after CPB (p ⬍ 0.0001) (Table 2). Most importantly, all 20 RACHS 1 patients and all but 2 (90%) of the 21 RACHS 2 patients were extubated in the OR compared with only 14 (54%) of the 26 RACHS 3 patients. Therefore, only RACHS 3 patients could be considered in investigating additional independent factors. Each of the factors listed in Table 2 was then tested to see if it distinguished the chance of extubation among the RACHS 3 patients. The only factor that showed any evidence of such an association was BMI; 75% of the 16 RACHS 3 patients with a BMI ⬍25 were extubated in the OR compared with 20% of the 10 RACHS 3 patients who had a BMI ⱖ25 (p ⫽ 0.01) (Fig 1). 100 90 80 70 60 50 40 30 20 10 0 RACHS 1+2
Fig 1. BMI.
RACHS 3, BMI <25
RACHS 3, BMI ≥25
The extubation rate based on the RACHS score and
ADULTS UNDERGOING SURGERY FOR CHD
It should be noted that among the RACHS 1 or 2 patients, half had a BMI ⬍25 and half ⱖ25, and 1 patient was not extubated in each of these groups. High inotrope use was explored in several ways, including as a continuous variable as well as comparing any inotrope use with no inotrope use. Inotrope use was not an independent predictor of OR extubation in the present patient population. All patients with a CPB time of ⬍60 minutes were extubated in the OR; however, once surgical risk (RACHS) was accounted for neither inotrope use nor CPB time contributed additional independent information. Similarly, none of the other factors included in the analysis (ie, age, reoperation, aortic cross-clamp time, procedure length, anesthesia length, body surface area, and sex) were associated independently with outcome. None of the patients who were extubated at the end of the procedure required reintubation either in the OR or at any time in the postoperative period in the ICU for respiratory-related complications. Hospital length of stay was significantly longer for the RACHS 3 group compared with the patients undergoing lower risk surgical procedures (median ⫽ 5.0 and 3.0 days, respectively, p ⫽ 0.01). Hospital length of stay was longer in patients in whom extubation was deferred regardless of RACHS classification. The length of stay for RACHS 3 patients with a BMI ⱖ25 was longer (median ⫽ 5.5) than for RACHS 3 patients with a BMI ⬍25 (median ⫽ 4.0), but this difference did not quite reach statistical significance (p ⫽ 0.07). There was no evidence that BMI influenced the length of stay of RACHS 1 and 2 patients (p ⫽ 0.65). DISCUSSION
Extubation in the OR in adult patients undergoing surgery for CHD is not common practice. Unlike the pediatric CHD surgery setting in which fast-tracking, including early extubation, routinely is performed in some institutions,7-10 data regarding this practice in adult patients undergoing cardiac surgery are limited to non-CHD cases. In the present study, the authors showed for the first time that extubation in the OR as part of a fast-tracking strategy is feasible and did not lead to an increase in reintubation rate in selected adult patients presenting for surgery for CHD. Fast-tracking in cardiac surgery typically refers to patient management that includes day-of-surgery admission, early extubation (removal of the endotracheal tube within 6-8 hours after surgery, including extubation in the OR at the end of the surgical procedure), rapid patient mobilization, and early ICU and hospital discharge. At this time, some form of fast-tracking, including early extubation, frequently is practiced in many routine adult cardiac surgery cases, such as on- and off-pump coronary artery bypass graft (CABG) surgery.3,11-13 To help select patients who are good candidates for fast-tracking, predictors for failure of such a strategy and factors associated with prolonged mechanical ventilation have been published. More than a decade ago, London et al14 found age, opioid dose, platelet transfusion, and inotrope use to be associated with the time to extubation in adult patients undergoing CABG surgery. Other risk factors frequently cited for the failure of an early extubation strategy include long CPB and aortic crossclamp times and very young or old age.7,15-17 In this analysis on adult CHD patients, RACHS alone predicted patients who eventually were extubated in the OR. It seems that the surgical risk classification (RACHS) “captures” possible ef-
775
fects of the other factors typically associated with delayed endotracheal extubation, including CPB time and aortic cross-clamp time, so that they did not add any additional independent information once RACHS had been considered. This is an important finding because it shows that a simple preoperatively known surgical risk classification can help predict good candidates for early extubation and fast-tracking. This also confirms the results from studies in children undergoing surgery for CHD in which RACHS predicted patients who required prolonged mechanical ventilation18,19 and adult patients undergoing CABG surgery in whom the European System for Cardiac Operative Risk score was associated with successful early extubation.20 The RACHS scoring system was developed by a panel of pediatric cardiologists and cardiac surgeons and is based on their clinical judgment of the complexity of the surgical procedure. Obviously, less complex, lower-risk surgery (lower RACHS scores) typically requires less time spent on CPB, which helps to explain why patients with low RACHS scores can be extubated early more frequently. It seems plausible that simple procedures, such as the repair of a secundum atrial septal defect (RACHS score 1) or the resection of a subaortic membrane (RACHS score 2), even in adult patients, should not require prolonged periods of postoperative mechanical ventilation, and in most cases those patients can be extubated in the OR. Fewer patients were extubated in the RACHS 3 group; however, it can be shown that adults undergoing even more complex CHD surgery do not necessarily need to be excluded from a fast-tracking strategy. Among the RACHS 3 patients, the endotracheal tube still was removed successfully at the end of the procedure in almost half of the cases. Within the RACHS 3 group, BMI further distinguished patients at high risk for deferred extubation at the end of the procedure in this patient population. It is interesting that being overweight had a significant impact in higher-risk surgical procedures, but it apparently did not affect early extubation for low-risk cardiac surgeries. Obesity has been identified as a common problem in children with CHD21 and is an additional factor contributing to cardiovascular morbidity in this population. Although there are no studies on perioperative complications in obese patients with CHD, obese adults undergoing CABG surgery have a higher failure rate of attempted early extubation compared with nonobese patients.22 Because the RACHS category and BMI generally are known at the time of preoperative counseling, the findings of this study add to the understanding of the individual’s chance of being fast-tracked, and this can be discussed with the patient. The practicability and benefits of fast-tracking have been discussed in detail in the literature; however, the data in adults are limited to non-CHD surgery. Benefits cited include the avoidance of the typical complications associated with prolonged endotracheal intubation such as accidental extubation, laryngotracheal trauma, mucous plugging of the endotracheal tube, and pulmonary hypertensive crisis secondary to suctioning of the endotracheal tube as well as ventilator-associated barotrauma, ventilator-associated infections, and atelectasis.9,12 Patients on mechanical ventilation require more sedation, often necessitating pharmacologic hemodynamic support. Patients who are extubated early usually can be mobilized much sooner after surgery, oral feeding can be commenced sooner, and regular bowel function resumes faster.
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All the aforementioned points help to discharge the patient earlier from the ICU and consequently from the hospital, with an overall reduction in resource use, higher OR throughput, and potential cost savings.23-25 Study Limitations The limitations of this study were that this study was based on a single center, had a relatively small sample size, and was retrospective. As such, it can only be concluded that OR extubation in this group of patients was feasible and was not associated with complications. For generalized recommendations about the safety of extubating adult CHD patients in the OR, larger possibly multicenter studies would be required. Also, this study did not aim to challenge established extubation criteria or to assess if extubation could have been accomplished in the few patients in whom the decision was made to defer the removal of the endotracheal tube to a later time. Such an investigation would have required extubating patients who clearly did not fulfill commonly accepted extubation criteria
and was considered unethical. The RACHS classification was developed for CHD patients under 18 years of age. In the present series, the authors chose to include the RACHS classification as a possible factor because there is no risk classification available specifically for adult CHD surgery and because of the ease of use and data availability. The finding that RACHS predicts OR extubation over other factors that were included in the present analysis is attractive because it is based solely on the type of CHD and planned surgery. CONCLUSIONS
Most of the adult patients in the present study presenting for surgery for CHD were extubated successfully at the end of the procedure in the OR. The strongest risk factor for deferring extubation was surgical risk classified with the RACHS score. BMI further helped distinguish patients in the higher surgical risk group who are more likely to fail this part of a fast-tracking strategy. The authors concluded that extubation in the OR after CHD surgery in adults is feasible.
REFERENCES 1. Opotowsky AR, Siddiqi OK, Webb GD: Trends in hospitalizations for adults with congenital heart disease in the U.S. J Am Coll Cardiol 54:460-467, 2009 2. Padalino MA, Cogo PE, Daliento L, et al: Congenital heart disease in adults: An 8-year surgical experience in a medium-volume cardiac center. J Cardiovasc Med 11:175-181, 2010 3. Myles PS, Daly DJ, Djaiani G, et al: A systematic review of the safety and effectiveness of fast-track cardiac anesthesia. Anesthesiology 99:982-987, 2003 4. Jenkins KJ, Gauvreau K, Newburger JW, et al: Consensus-based method for risk adjustment for surgery for congenital heart disease. J Thorac Cardiovasc Surg 123:110-118, 2002 5. Wernovsky G, Wypij D, Jonas RA, et al: Postoperative course and hemodynamic profile after arterial switch surgery in neonates and infants: A comparison of low-flow cardiopulmonary bypass and circulatory arrest. Circulation 92:2226-2235, 1995 6. Hoffman TM, Wernovsky G, Atz AM, et al: Efficacy and safety of milrinone in preventing low cardiac output syndrome in infants and children after corrective surgery for congenital heart disease. Circulation 107:996-1002, 2003 7. Vricella LA, Dearani JA, Gundry SR, et al: Ultra fast track in elective congenital cardiac surgery. Ann Thorac Surg 69:865-871, 2000 8. Mittnacht AJ, Thanjan M, Srivastava S, et al: Extubation in the operating room after congenital heart surgery in children. J Thorac Cardiovasc Surg 136:88-93, 2008 9. Neirotti RA, Jones D, Hackbarth R, et al: Early extubation in congenital heart surgery. Heart Lung Circ 11:157-161, 2002 10. Heinle JS, Diaz LK, Fox LS: Early extubation after cardiac operations in neonates and young infants. J Thorac Cardiovasc Surg 114:413-418, 1997 11. Djaiani GN, Ali M, Heinrich L, et al: Ultra-fast-track anesthetic technique facilitates operating room extubation in patients undergoing off-pump coronary revascularization surgery. J Cardiothorac Vasc Anesth 15:152-157, 2001 12. Cheng DC, 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 112:755-764, 1996 13. Svircevic V, Nierich AP, Moons KGM, et al: Fast-track anesthesia and cardiac surgery: A retrospective cohort study of 7989 patients. Anesth Analg 108:727-733, 2009
14. London MJ, Shroyer AL, Coll JR, et al: Early extubation following cardiac surgery in a veterans population. Anesthesiology 88: 1447-1458, 1998 15. Davis S, Worley S, Mee RBB, et al: Factors associated with early extubation after cardiac surgery in young children. Pediatr Crit Care Med 5:63-68, 2004 16. Harrison AM, Cox AC, Davis S, et al: Failed extubation after cardiac surgery in young children: Prevalence, pathogenesis, and risk factors. Pediatr Crit Care Med 3:148-152, 2002 17. Bandla HPR, Hopkins RL, Beckerman RC, et al: Pulmonary risk factors compromising postoperative recovery after surgical repair for congenital heart disease. Chest 116:740-747, 1999 18. Kin N, Weismann C, Srivastava S, et al: Factors affecting the decision to defer endotracheal extubation after surgery for congenital heart disease: A prospective observational study. Anesth Analg 113:329-335, 2011 19. Shi S, Zhao Z, Liu X, et al: Perioperative risk factors for prolonged mechanical ventilation following cardiac surgery in neonates and young infants. Chest 134:768-774, 2008 20. Sato M, Suenaga E, Koga S, et al: Early tracheal extubation after on-pump coronary artery bypass grafting. Ann Thorac Cardiovasc Surg 15:239-242, 2009 21. Pinto NM, Marino BS, Wernovsky G, et al: Obesity is a common comorbidity in children with congenital and acquired heart disease. Pediatrics 120:1157-1164, 2007 22. Parlow JL, Ahn R, Milne B: Obesity is a risk factor for failure of “fast track” extubation following coronary artery bypass surgery. Can J Anaesth 53:288-294, 2006 23. vanMastrigt GA, Maessen JG, Heijmans J, et al: Does fast-track treatment lead to decrease of intensive care unit and hospital length of stay in coronary artery bypass patients? A meta-regression of randomized clinical trials. Crit Care Med 34:1624-1634, 2006 24. Cheng DC, Karski J, Pensiton C, et al: Early extubation after coronary artery bypass graft surgery reduces costs and improves resource use: A prospective, randomized, controlled trial. Anesthesiology 85:1300-1310, 1996 25. Chamchad D, Horrow JC, Nachamchik L, et al: The impact of immediate extubation in the operating room after cardiac surgery on intensive care and hospital length of stay. J Cardiothorac Vasc Anesth 24:780-784, 2010
79% of patients were extubated in the OR. The RACHS score was the strongest predictor of deferring extubation (RACHS 3 v 1 or 2: odds ratio ⴝ 16.7; 95% confidence interval, 3.384.2; p ⴝ 0.0006). Further exploration of the high-risk group (RACHS 3) showed that 75% of the RACHS 3 patients with a body mass index <25 were extubated compared with only 20% of patients who had a body mass index >25 (p ⴝ 0.01). Other factors included in the analysis did not contribute any additional independent information. Conclusions: Extubation of adult patients in the OR after surgery for congenital heart disease is feasible in most cases. Surgical risk (RACHS score) and body mass index predict the decision for OR extubation in this patient population. © 2012 Elsevier Inc. All rights reserved.
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all patients except those undergoing simple procedures had central venous access established before skin incision. A multiplane transesophageal echocardiographic probe (Siemens Medical Solutions USA, Inc, Malvern, PA) was inserted for intraoperative hemodynamic monitoring and to evaluate the surgical repair. After the administration of heparin (300 U/kg), the ascending aorta and inferior and superior vena cava were cannulated, and full CPB was established. A potent inhalation agent (eg, isoflurane or sevoflurane) was administered throughout the case including while the patient was on CPB. At the end of the surgical procedure, after the discontinuation of CPB, modified ultrafiltration was performed in all patients followed by heparin reversal with protamine based on a protamine-titration assay. The practice standard was to extubate all eligible patients in the OR. However, the final decision to attempt extubation in the OR was made by the attending surgeon and anesthesiologist at the end of the procedure. Patients were considered for extubation if they were hemodynamically stable without excessive inotropic support (total inotrope score ⱕ20 and epinephrine or norepinephrine each ⱕ0.05 g/kg/min), had a core body temperature ⬎35°C, had no signs of upper-airway edema, and showed no evidence of coagulopathy requiring continuous administration of blood products. In patients in whom these criteria were met, residual neuromuscular blockade was reversed with neostigmine and glycopyrrolate. Additional extubation criteria applied included the following parameters: an
HE NUMBER OF adult patients presenting for surgery for congenital heart disease (CHD) has increased.1,2 Although fast-tracking is practiced routinely in adult patients undergoing cardiac surgery not related to CHD,3 this approach is more controversial and has not been reported in adults undergoing surgery for CHD, and mechanical ventilation typically is continued postoperatively in the intensive care unit (ICU). At the authors’ institution, it has become routine practice to consider patients undergoing surgery for CHD for fast-tracking, including extubation in the operating room (OR). In this study, the authors report their experience with OR extubation in the adult CHD surgery patient population and discuss the factors associated with deferring extubation to a later time. METHODS After institutional review board approval, a retrospective database review of adult patients undergoing surgery for CHD at a tertiary-care teaching hospital between June 2003 and April 2009 was conducted. Inclusion criteria were as follows: patients ⱖ18 years of age and patients who had CHD surgery using cardiopulmonary bypass (CPB). Exclusion criteria were age ⬎70 years, surgery not requiring CPB, preoperative mechanical ventilation, thoracic organ transplantation, and a Risk Adjustment for Congenital Heart Surgery (RACHS)4 score ⱖ4. Excessive inotrope use after CPB is considered a contraindication for early extubation in the authors’ institution, and patients with an inotrope score ⬎205,6 also were excluded from the analyses. Anesthesia was induced with etomidate, 0.2 mg/kg, or propofol, 2 to 3 mg/kg intravenously, supplemented with fentanyl, 2 to 3 g/kg intravenously, and vecuronium, 0.1 mg/kg, for neuromuscular blockade and maintained with a potent volatile agent (isoflurane, sevoflurane, or desflurane) in air/oxygen. Unless contraindications applied, preservative-free morphine (7-10 g/kg) was administered intrathecally. Additional intravenous fentanyl was administered as needed and limited to a maximum cumulative dose of 5 g/kg. All patients had their arterial blood pressure monitored continuously with an indwelling catheter, and
KEY WORDS: congenital heart defects, cardiac surgery, fasttracking, cardiac anesthesia, ventilator, mechanical, intubation, tracheal, intensive care unit
From the *Division of Pediatric Cardiology, Yale University School of Medicine, New Haven, CT; †University of Toledo College of Medicine, Toledo, OH; and Departments of ‡Anesthesiology and §Cardiothoracic Surgery, The Mount Sinai School of Medicine, New York, NY. Address reprint requests to Alexander J.C. Mittnacht, MD, Department of Anesthesiology, The Mount Sinai Medical Center, Box 1010, One Gustave L Levy Place, New York, NY 10029. E-mail: [email protected] © 2012 Elsevier Inc. All rights reserved. 1053-0770/2605-0004$36.00/0 http://dx.doi.org/10.1053/j.jvca.2012.04.009
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adequate level of consciousness, intact protective airway reflexes, adequate pain control, arterial blood gas results indicating adequate oxygenation, and a tidal volume ⱖ6 mL/kg. Once the patient was breathing spontaneously with adequate respiratory parameters, the endotracheal tube was removed, and oxygen was administered via a nasal cannula. A continuous infusion of dexmedetomidine (0.4-0.8 g/kg/h) was started before transfer to the cardiac ICU, and intravenous fentanyl or morphine was given to patients with signs of inadequate analgesia. Patients in whom the attending anesthesiologist and surgeon made the decision not to proceed with extubation were transferred to the ICU intubated. The primary outcome was defined as deferring planned immediate OR extubation. Continuous variables were grouped, and each potential perioperative risk factor was screened individually to determine any association with not proceeding using the chi-square, Fisher exact, or the Cochran-Armitage test for trend as appropriate. Stepwise logistic regression was used to identify independent factors. When it became evident that almost all the patients with RACHS scores of 1 or 2 were extubated in the OR, the analyses were repeated for the subgroup of patients with an RACHS score of 3 alone. Characteristics of the patients with an RACHS score of 3 were compared with those of patients with an RACHS score of 1 or 2 using the Wilcoxon or chi-square tests. Statistical significance was defined as p ⬍ 0.05. The following perioperative factors were tested: age, body surface area, body mass index (BMI), sex, CPB time, aortic cross-clamp time, procedure length, anesthesia length, inotrope score, surgical risk (RACHS score), and prior cardiac surgery (reoperation). RESULTS
The chart review identified 72 patients who met the preoperative inclusion criteria. Five of these were excluded from the final analysis because of significant inotrope use after separation from CPB (inotrope score ⬎20). A total of 67 patients (age 18-59 years, median ⫽ 32 years) were included in the analysis. Overall, 79% (53/67) of patients were extubated at the end of the surgical procedure in the OR. Table 1 lists the type of
Table 1. Procedure Complexity, Cases/Procedures Performed, and the Patients Extubated in the OR RACHS
1 2
3
Case/Procedure
n
OR Extubation
ASD (secundum) ASD (sinus venosus) ASD (primum) VSD PVR RVOT reconstruction TOF Conduit revision Fontan TV repair Asc Ao/Ao root replacement AVR MV repair Unroofing of ACA DORV cAVC
16 4 4 5 9 2 1 5 3 6 4 1 4 1 1 1
16 4 3 5 8 2 1 3 2 2 2 0 2 1 1 1
Abbreviations: ASD, atrial septal defect; VSD, ventricular septal defect; PVR, pulmonary valve replacement; RVOT, right ventricular outflow tract; TOF, tetralogy of Fallot; TV, tricuspid valve; Asc, ascending; Ao, aorta; AVR, aortic valve replacement; MV, mitral valve; ACA, anomalous coronary artery; DORV, double-outlet right ventricle; cAVC, complete atrioventricular canal defect.
Table 2. Factors Included in the Analysis Factor
RACHS 1, 2 (n ⫽ 41)
RACHS 3 (n ⫽ 26)
p Value
Age BMI ⱖ25 (%) Men (%) Reoperation (%) Inotrope use (%) AoX time (min) CPB time (min) Procedure time (min) Anesthesia time (min)
32 (18-59) 21 (51) 17 (41) 11 (27) 6 (15) 17 (0-173) 66 (7-203) 224 (121-443) 339 (195-576)
23 (18-54) 10 (38) 17 (65) 15 (58) 17 (65) 91 (0-326) 162 (86-391) 356 (202-812) 467 (334-943)
0.05 0.31 0.06 0.01 ⬍0.0001 0.002 ⬍0.0001 ⬍0.0001 ⬍0.0001
NOTE. Data displayed as median (minimum, maximum) or number (%); p values included when groups were compared. Abbreviation: AoX, aortic cross-clamp.
cases/procedures performed, their RACHS classification, and the number of patients who were extubated in the OR. Logistic regression analysis of each factor on all 67 eligible patients revealed that surgical risk classified by the RACHS score was the strongest predictor of deferring endotracheal extubation (RACHS 3 v 1 or 2: odds ratio ⫽ 16.7; 95% confidence interval, 3.3-84.2, p ⫽ 0.0006). Further examination of the data found that patients who were classified as RACHS category 1 or 2 differed markedly from the RACHS category 3 patients in most factors under consideration. When compared with the RACHS 1 and 2 patients, patients in the RACHS 3 group were younger (p ⫽ 0.05); had longer CPB, aortic cross-clamp, procedure, and anesthesia times (p ⬍ 0.0001, p ⫽ 0.002, p ⱕ 0.0001, and p ⬍ 0.0001, respectively); and required more inotropic support after CPB (p ⬍ 0.0001) (Table 2). Most importantly, all 20 RACHS 1 patients and all but 2 (90%) of the 21 RACHS 2 patients were extubated in the OR compared with only 14 (54%) of the 26 RACHS 3 patients. Therefore, only RACHS 3 patients could be considered in investigating additional independent factors. Each of the factors listed in Table 2 was then tested to see if it distinguished the chance of extubation among the RACHS 3 patients. The only factor that showed any evidence of such an association was BMI; 75% of the 16 RACHS 3 patients with a BMI ⬍25 were extubated in the OR compared with 20% of the 10 RACHS 3 patients who had a BMI ⱖ25 (p ⫽ 0.01) (Fig 1). 100 90 80 70 60 50 40 30 20 10 0 RACHS 1+2
Fig 1. BMI.
RACHS 3, BMI <25
RACHS 3, BMI ≥25
The extubation rate based on the RACHS score and
ADULTS UNDERGOING SURGERY FOR CHD
It should be noted that among the RACHS 1 or 2 patients, half had a BMI ⬍25 and half ⱖ25, and 1 patient was not extubated in each of these groups. High inotrope use was explored in several ways, including as a continuous variable as well as comparing any inotrope use with no inotrope use. Inotrope use was not an independent predictor of OR extubation in the present patient population. All patients with a CPB time of ⬍60 minutes were extubated in the OR; however, once surgical risk (RACHS) was accounted for neither inotrope use nor CPB time contributed additional independent information. Similarly, none of the other factors included in the analysis (ie, age, reoperation, aortic cross-clamp time, procedure length, anesthesia length, body surface area, and sex) were associated independently with outcome. None of the patients who were extubated at the end of the procedure required reintubation either in the OR or at any time in the postoperative period in the ICU for respiratory-related complications. Hospital length of stay was significantly longer for the RACHS 3 group compared with the patients undergoing lower risk surgical procedures (median ⫽ 5.0 and 3.0 days, respectively, p ⫽ 0.01). Hospital length of stay was longer in patients in whom extubation was deferred regardless of RACHS classification. The length of stay for RACHS 3 patients with a BMI ⱖ25 was longer (median ⫽ 5.5) than for RACHS 3 patients with a BMI ⬍25 (median ⫽ 4.0), but this difference did not quite reach statistical significance (p ⫽ 0.07). There was no evidence that BMI influenced the length of stay of RACHS 1 and 2 patients (p ⫽ 0.65). DISCUSSION
Extubation in the OR in adult patients undergoing surgery for CHD is not common practice. Unlike the pediatric CHD surgery setting in which fast-tracking, including early extubation, routinely is performed in some institutions,7-10 data regarding this practice in adult patients undergoing cardiac surgery are limited to non-CHD cases. In the present study, the authors showed for the first time that extubation in the OR as part of a fast-tracking strategy is feasible and did not lead to an increase in reintubation rate in selected adult patients presenting for surgery for CHD. Fast-tracking in cardiac surgery typically refers to patient management that includes day-of-surgery admission, early extubation (removal of the endotracheal tube within 6-8 hours after surgery, including extubation in the OR at the end of the surgical procedure), rapid patient mobilization, and early ICU and hospital discharge. At this time, some form of fast-tracking, including early extubation, frequently is practiced in many routine adult cardiac surgery cases, such as on- and off-pump coronary artery bypass graft (CABG) surgery.3,11-13 To help select patients who are good candidates for fast-tracking, predictors for failure of such a strategy and factors associated with prolonged mechanical ventilation have been published. More than a decade ago, London et al14 found age, opioid dose, platelet transfusion, and inotrope use to be associated with the time to extubation in adult patients undergoing CABG surgery. Other risk factors frequently cited for the failure of an early extubation strategy include long CPB and aortic crossclamp times and very young or old age.7,15-17 In this analysis on adult CHD patients, RACHS alone predicted patients who eventually were extubated in the OR. It seems that the surgical risk classification (RACHS) “captures” possible ef-
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fects of the other factors typically associated with delayed endotracheal extubation, including CPB time and aortic cross-clamp time, so that they did not add any additional independent information once RACHS had been considered. This is an important finding because it shows that a simple preoperatively known surgical risk classification can help predict good candidates for early extubation and fast-tracking. This also confirms the results from studies in children undergoing surgery for CHD in which RACHS predicted patients who required prolonged mechanical ventilation18,19 and adult patients undergoing CABG surgery in whom the European System for Cardiac Operative Risk score was associated with successful early extubation.20 The RACHS scoring system was developed by a panel of pediatric cardiologists and cardiac surgeons and is based on their clinical judgment of the complexity of the surgical procedure. Obviously, less complex, lower-risk surgery (lower RACHS scores) typically requires less time spent on CPB, which helps to explain why patients with low RACHS scores can be extubated early more frequently. It seems plausible that simple procedures, such as the repair of a secundum atrial septal defect (RACHS score 1) or the resection of a subaortic membrane (RACHS score 2), even in adult patients, should not require prolonged periods of postoperative mechanical ventilation, and in most cases those patients can be extubated in the OR. Fewer patients were extubated in the RACHS 3 group; however, it can be shown that adults undergoing even more complex CHD surgery do not necessarily need to be excluded from a fast-tracking strategy. Among the RACHS 3 patients, the endotracheal tube still was removed successfully at the end of the procedure in almost half of the cases. Within the RACHS 3 group, BMI further distinguished patients at high risk for deferred extubation at the end of the procedure in this patient population. It is interesting that being overweight had a significant impact in higher-risk surgical procedures, but it apparently did not affect early extubation for low-risk cardiac surgeries. Obesity has been identified as a common problem in children with CHD21 and is an additional factor contributing to cardiovascular morbidity in this population. Although there are no studies on perioperative complications in obese patients with CHD, obese adults undergoing CABG surgery have a higher failure rate of attempted early extubation compared with nonobese patients.22 Because the RACHS category and BMI generally are known at the time of preoperative counseling, the findings of this study add to the understanding of the individual’s chance of being fast-tracked, and this can be discussed with the patient. The practicability and benefits of fast-tracking have been discussed in detail in the literature; however, the data in adults are limited to non-CHD surgery. Benefits cited include the avoidance of the typical complications associated with prolonged endotracheal intubation such as accidental extubation, laryngotracheal trauma, mucous plugging of the endotracheal tube, and pulmonary hypertensive crisis secondary to suctioning of the endotracheal tube as well as ventilator-associated barotrauma, ventilator-associated infections, and atelectasis.9,12 Patients on mechanical ventilation require more sedation, often necessitating pharmacologic hemodynamic support. Patients who are extubated early usually can be mobilized much sooner after surgery, oral feeding can be commenced sooner, and regular bowel function resumes faster.
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All the aforementioned points help to discharge the patient earlier from the ICU and consequently from the hospital, with an overall reduction in resource use, higher OR throughput, and potential cost savings.23-25 Study Limitations The limitations of this study were that this study was based on a single center, had a relatively small sample size, and was retrospective. As such, it can only be concluded that OR extubation in this group of patients was feasible and was not associated with complications. For generalized recommendations about the safety of extubating adult CHD patients in the OR, larger possibly multicenter studies would be required. Also, this study did not aim to challenge established extubation criteria or to assess if extubation could have been accomplished in the few patients in whom the decision was made to defer the removal of the endotracheal tube to a later time. Such an investigation would have required extubating patients who clearly did not fulfill commonly accepted extubation criteria
and was considered unethical. The RACHS classification was developed for CHD patients under 18 years of age. In the present series, the authors chose to include the RACHS classification as a possible factor because there is no risk classification available specifically for adult CHD surgery and because of the ease of use and data availability. The finding that RACHS predicts OR extubation over other factors that were included in the present analysis is attractive because it is based solely on the type of CHD and planned surgery. CONCLUSIONS
Most of the adult patients in the present study presenting for surgery for CHD were extubated successfully at the end of the procedure in the OR. The strongest risk factor for deferring extubation was surgical risk classified with the RACHS score. BMI further helped distinguish patients in the higher surgical risk group who are more likely to fail this part of a fast-tracking strategy. The authors concluded that extubation in the OR after CHD surgery in adults is feasible.
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