Extubation in the Operating Room After Cardiac Surgery in Children: A Prospective Observational Study With Multidisciplinary Coordinated Approach Rajnish Garg, MD, Shekhar Rao, MCh, Colin John, MCh, Chinnaswamy Reddy, MCh, Rajesh Hegde, MD, Keshava Murthy, MD, and PVS Prakash, BSc Objective: This prospective observational study was undertaken to determine the feasibility of extubation of children in the operating room after cardiac surgery. Design: A prospective observational study compared with historic controls. Setting: A single tertiary care referral hospital. Participants: One thousand consecutive pediatric patients requiring cardiac surgery aged 1 day to 18 years. Patients with spinal deformity, neurologic problems, coagulopathy as diagnosed by high international normalized ratio (INR) more than 1.5, and patients preoperatively on mechanical ventilation were excluded from the study. Data were also reviewed for another 1,000 patients operated before the beginning of this study, which constituted historic controls. Interventions: All 1,000 patients were considered as potential candidates for extubation in the operating room after cardiac surgery and managed by a combination of general anesthesia and neuraxial analgesia with a mixture of caudal morphine and dexmedetomidine, and extubation in the operating room was attempted after completion of the surgical procedure. These comprised the study group (SG). Data also were reviewed for another 1,000 patients before the beginning of this study when extubation in the operating room was not attempted and compared with this group to study the impact of extubation in the operating room on

intensive care unit (ICU) stay and resource utilization. This data comprised the before-study group (BSG). Measurements and Main Results: Eight hundred seventyone (87.1%) patients were extubated in the operating room. This included 40% of neonates and 70%, 85%, and 91% of patients aged between 1 and 3 months, 3 months to 1 year, and more than 1 year, respectively. Forty-five patients (4.5%) required re-intubation within 24 hours, and 9 patients died among those extubated in the OR, but for reasons thought not to be related to extubation. The ICU stay was significantly less in the study group (2.56 ⫾ 1.84 v 5.4 ⫾ 2.32 days, p o 0.0001) as compared to before-study group (BSG). The number of patients in the ICU (34.76 ⫾ 3.19 v 59.98 ⫾ 4.92, p o 0.0001) and the number of patients on a ventilator (5.1 ⫾ 1.24 v 24.5 ⫾ 2.88, p o 0.0001) on a daily basis were significantly less in the study group, reflecting positive impact on resource utilization. Conclusion: Extubation in the operating room was successful in 87.1% of the patients without any increase in mortality and morbidity, but with a decrease in ICU length of stay and less use of hospital resources. & 2014 Elsevier Inc. All rights reserved.

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children with coordination among the surgeon, anesthesiologist, perfusionist and intensivist. All the patients were managed as potential candidates for extubation in the OR. The decision to extubate was made at the end of surgery by the surgeon and the anesthesiologist. The factor responsible for deferring extubation in a particular patient was noted. The data in this study group (SG) were compared with the before-study group (BSG).

HE PRACTICE OF EXTUBATION after pediatric cardiac surgery differs from institution to institution. Many institutions advocate continued ventilation, high-dose narcotic sedation, and often paralysis during initial postoperative recovery to minimize the stress response to surgery, prevent pulmonary artery hypertension (PAH) episodes, and improve outcome.1–4 With continued improvement in anesthetic, surgical, and perfusion management of patients undergoing surgery for congenital heart disease, the need to routinely continue ventilation in the postoperative period can be reduced. Extubation in the operating room (OR) after surgery for congenital heart disease in children has been reported as early as in 1980 when Barash5 and colleagues published their experience. They studied 197 patients younger than 3 years (including neonates) and were able to successfully extubate 61% of them in the operating room. Recently, several retrospective6–11 and 1 prospective study by Preisman and colleagues12 has shown the feasibility and safety of early extubation of pediatric cardiac patients, including neonates who were at high risk for a complicated postoperative course. The proposed benefits of early extubation include fewer pulmonary complications, shorter intensive care unit (ICU) and hospital stay, reduced costs, and better resource utilization.13–17 The authors hypothesized that extubation in the operating room may be accomplished safely by managing the patients with a multidisciplinary coordinated approach involving the surgeon, anesthesiologist, perfusionist, and intensivist. The authors undertook this prospective observational study to evaluate the feasibility and safety of extubation in the operating room after surgery for congenital heart disease in

KEY WORDS: early extubation, congenital heart surgery, safety

pediatric

anesthesia,

METHODS After institutional review board approval and informed consent from the patients’ parents, the authors enrolled 1,000 consecutive children, aged between 1 day to 18 years, scheduled for elective cardiac surgery for congenital heart disease with or without cardiopulmonary bypass (CPB) between October 1, 2012 to May 21, 2013. All the patients were managed as potential candidates for extubation in the OR. Patients with pulmonary artery hypertension (PAH) also were considered as potential candidates for extubation. Patients who had anatomical abnormalities of the sacrum or neural tube defects and raised

From the Division of Pediatric Cardiac Sciences, Narayana Institute of Cardiac Sciences, Bangalore, India. Address reprint requests to Rajnish Garg, MD, Senior Consultant Cardiac Anesthesiologist, Narayana Institute of Cardiac Sciences, Division of Pediatric Cardiac Sciences, 258/A Bommasandra Industrial Area, Hosur Road, Bangalore, India 560099. E-mail: gargrajnish11@ gmail.com © 2014 Elsevier Inc. All rights reserved. 1053-0770/2601-0001$36.00/0 http://dx.doi.org/10.1053/j.jvca.2014.01.003

Journal of Cardiothoracic and Vascular Anesthesia, Vol ], No ] (Month), ]]]]: pp ]]]–]]]

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international normalized ratio (INR) of more than 1.5 were not included in the study, as the authors used neuraxial analgesia in the form of caudal epidural morphine and dexmedetomidine. Patients preoperatively on mechanical ventilation also were excluded from the study. In the intraoperative period there was a close coordination among the surgeon, anesthesiologist, and perfusionist. Particular attention was paid to pain management, intraoperative fluid balance, and surgical repair and their assessment by transesophageal echocardiography and hemostasis. The goal of the surgeon was to ensure good corrective/ palliative surgical repair without any residual defect and good surgical hemostasis. The anesthesiologist’s goal was to provide balanced surgical anesthesia. The goal of the perfusionist was to avoid excessive increase in body water, which was achieved by reducing prime volume and miniaturization of the circuit and by utilizing conventional (CUF) and modified ultrafiltration (MUF). In the postoperative period, the goal of the intensivist in the ICU was to ensure hemodynamic and arterial blood gas (ABG) monitoring, sedation, and analgesia. After transferring to the ICU, every patient would undergo transthoracic echocardiography by a cardiologist as baseline for assessment of surgical repair, cardiac function, diaphragm movement, and pulmonary artery pressure in patients with pulmonary artery hypertension. Transthoracic echocardiography would be repeated within 6-8 hours for reassessment. In addition, in the event of echocardiographic finding of deteriorating cardiac function the intensivist would re-intubate even though hemodynamic and biochemical parameters remained stable. The staff nurse was well informed of the protocol, and her goal was to ensure continuous monitoring of the vital signs. The respiratory physiotherapist’s role was to ensure a clear airway by gentle suctioning of the nasopharynx and oropharynx every 2 hours and to start chest physiotherapy as early as possible after discussion with the intensivist. In all patients with reported PAH, mean pulmonary artery pressure (MPAP) was compared with mean systemic arterial pressure (MSAP) before and after the surgical repair. The authors divided the patients into 3 categories: Patients with MPAP/MSAP less than 0.4 as mild, between 0.4 and 0.7 as moderate, and more than 0.7 as severe PAH. Patients with MPAP/MSAP more than 0.7 would be given oral sildenafil, 0.5 to 1.0 mg/kg, via a nasogastric tube in the ICU. In addition, transthoracic echocardiography would be done to assess pulmonary artery pressure, right ventricular function, left ventricular function, and interventricular septum. Anesthetic management in all patients consisted of mask induction of anesthesia with sevoflurane in a nitrous oxide/oxygen mixture. After intravenous access was secured, fentanyl was administered in a dose of 3 μg/kg. Tracheal intubation was facilitated by 0.1 mg/kg of pancurnium bromide. After tracheal intubation, a mixture of preservative-free morphine, 100 μg/kg and dexmedetomidine, 1 μg/kg diluted in normal saline solution to 1 mL/kg were administered in a single-shot injection with a 22-g to 24-g needle in the caudal epidural space. Detrimental side effects like bradycardia and decrease in systemic vascular resistance, especially in right-to-left shunt patients, have been described after intravenous administration of dexmedetomidine. Although not typically seen with single-shot epidural administration, the authors were still prepared to manage these with the help of atropine and phenylephrine. An indwelling catheter for continuous arterial blood pressure monitoring and a central venous catheter for monitoring filling pressure and administration of inotropes and drugs was inserted before skin incision. Anesthesia was maintained with isoflurane 0.5% to 1%, titrated on the basis of clinical indicators of depth of anesthesia and minimal narcotic limited to less than 5 mcg/kg of fentanyl. During CPB, isoflurane was continued by means of a vaporizer inserted in the gas supply line of the extracorporeal circuit. An additional dose of pancuronium, 0.02 mg/kg, was given if required during the surgery. A pediatric multiplane transesophageal echocardiography (TEE) probe (Philips

GARG ET AL

Ultrasound, Bothell, WA) was inserted for intraoperative monitoring and evaluating the surgical repair in the OR. After a minimum of 60 minutes of caudal block, heparin, 400 U/kg, was administered. CPB was initiated after aortic bicaval cannulation and included a hard-shell venous reservoir and low-prime membrane oxygenator (Medtronic, Inc., Minneapolis, MN). Cold blood cardioplegia (St. Thomas Hospital cardioplegic solution), 20 mL/kg, was administered in a ratio of 4 parts blood to 1 part crystalloid cardioplegia solution into the aortic root and repeated every 20 minutes. Priming fluids consisted of lactated Ringer’s solution and heparin and supplemented with 5 mL to 10 mL of 20% albumin to help coating of the circuit. Fresh whole blood (less than 48 hours old) was added to the priming solution in appropriate amounts to achieve a hematocrit of 25% to 30% during CPB. The pump flow rate was maintained at 150 mL/kg/ min to 200 mL/kg/min, and alpha-stat strategy was used for blood gas management. According to the authors’ institutional protocol, all the children underwent continuous ultrafiltration during CPB and modified ultrafiltration after termination of CPB for 10 to 15 minutes. The target for CUF was to remove all excess volume more than the minimum operating volume in the venous reservoir. Patients were rewarmed to 36° centigrade. At the end of the surgical procedure, surgical repair was assessed with the help of TEE after discontinuation of CPB. MUF was done for 10 to 15 minutes by withdrawing blood from the aorta at a rate of 5 mL/kg to 7 mL/kg/min up to a maximum of 30 mL/min, and the target after MUF was to achieve a hematocrit of 35% to 40%. During MUF, however, the patient’s temperature dropped by 0.5 to 1.0° centigrade, and care was taken to maintain temperature with the help of a water blanket connected to circulating warm water through a heater-cooler unit. The head and limbs were covered with a cotton pad, and warm air was blown under the surgical drapes. Keeping a low rate of withdrawing blood from the aorta helped in achieving a slower fall and less of a fall in nasopharyngeal temperature. After MUF, heparin was reversed with protamine. At the end of the surgery, the decision to extubate the patients was made after discussion with the surgeon. If any one of the following conditions was present by the end of the operation, extubation was not pursued: (1) primary closure of the sternum was not done, (2) arterial oxygen tension (PaO2) less than 80 mmHg in patients in whom total correction was done and 55 mmHg in patients in whom palliative procedure was done with an inspired oxygen fraction of 0.50 and arterial carbon dioxide tension (PaCO2) more than 55 mmHg, (3) unsatisfactory hemostasis requiring transfusion of packed red blood cells more than 20% of blood volume during the post-bypass period, (4) any other surgical concern due to patient factors such as suboptimal native morphology due to which the surgeon feels the need for observation in the intensive care unit for some time to assess the postoperative behavior, and (5) hemodynamic instability requiring more than 7.5 μg/kg/min of dobutamine and 0.075 μg/kg/min of epinephrine (equivalent to inotrope score18 of more than 15). In the absence of the above-mentioned factors, if the patient was hemodynamically stable, neuromuscular blockade was reversed with neostigmine, 0.05 mg/kg, and glycopyrrolate, 0.005 mg/kg. As soon as the patient had good ventilatory effort as assessed by respiratory rate less than 30/minute, tidal volume 8 mL/kg to 10 mL/kg and absence of accessory respiratory muscle recruitment along with satisfactory gas exchange with pH more than 7.30, bicarbonate (HCO3) between 22 mmol/L and 27 mmol/L and PaO2 and PaCO2 according to abovementioned criteria, depending upon the lesion, the endotracheal tube was removed and oxygen was administered via nasal cannula. If any patient was agitated, intravenous midazolam, 0.1 mg/kg, was administered. In the ICU, these patients were assessed by the intensivists and given sedatives and analgesics. Either intravenous bolus midazolam or dexmedetomidine/fentanyl infusion was titrated to maintain a face, legs, activity, crying, consolation (FLACC) score19 of less than 2.

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EXTUBATION IN CHILDREN AFTER CARDIAC SURGERY

Patients who were not extubated in the operating room due to concerns like bleeding, pulmonary dysfunction, or cardiac dysfunction were shifted to the ICU and placed on a regimen of sedation and paralysis. According to the standard extubation criteria,20 these patients were extubated in the ICU by intensivists, and the time to extubation was noted. The factor responsible for deferring extubation in the operating room was noted in these patients. To study the impact of extubation in the operating room on resource utilization, the authors recorded the total number of patients and the number of patients on a ventilator in the ICU on a daily basis. The length of ICU stay of each patient also was recorded. All these patients comprised the study group (SG). In addition to the study group, the records of 1,000 consecutive patients with similar demographic and perioperative characteristics in the preceding period (February 27, 2012 through September 30, 2012) were reviewed. These patients were routinely sedated, paralyzed and ventilated postoperatively. The anesthetic protocol as described in the study group also was followed in these patients except that fentanyl, 20 to 40 μg/kg, was used intraoperatively instead of neuraxial analgesia. In the immediate postoperative period, patients were sedated with 1 to 3 μg/kg/h of fentanyl and intermittently paralyzed with vecuronium bromide. Weaning from mechanical ventilation was commenced early morning on the first postoperative day, as per institutional practice of precluding weaning during the nightshift, due to workforce constraints. These patients were extubated in the ICU by intensivists according to the standard extubation criteria.20 The total number of patients and the number of patients on a ventilator, on a daily basis, were noted from ICU records. Patients’ records were also reviewed for the length of ICU stay. These data comprised the beforestudy group (BSG). Data analysis was done with the help of a computer using Epidemiological Information Package (EPI 2010) developed by the Centers for Disease Control, Atlanta, GA. Using this software range, frequencies, percentages, means, standard deviations and p values were calculated. Student t test was used to test the significance of difference among quantitative variables. A p value less than 0.05 was taken to denote significant relationship. RESULTS

The recorded data of all 1,000 patients were analyzed. The perioperative characteristics of the patients are shown in Table 1. Figure 1 shows the flow chart for the outcome of all the patients. Overall, 87.1% of the patients were extubated in the OR. Tables 2 and 3 list the details of patients extubated out of the total along with the percentage depending upon the type of case/procedure performed and the age, respectively. Out of the 871 patients extubated in the OR, none of the patients required re-intubation for respiratory-related complication such as respiratory depression, inadequate oxygenation, and lung atelectasis; whereas 45 patients were reintubated for other reasons. Most of the patients extubated in the OR showed mild respiratory acidosis (PaCO2 50-55 mmHg) with pH in the range of 7.28-7.32 in the first arterial blood gas (ABG) in the ICU, which normalized in the subsequent ABGs within 1 to 2 hours without any intervention. Pao2 and HCO3 were within normal limits. Patients did not require additional analgesia for at least 6 hours in the ICU after which, in children more than 1 year of age, parenteral ketorolac was administered prophylactically for analgesia, although the effect of caudal morphine may last up to 24 hours, and an intermittent bolus of 0.1 mg/kg of intravenous midazolam was administered for sedation. In patients younger than 1 year, a low dose of dexmedetomidine

Table 1. Perioperative Characteristics of the Patients Age

Neonates 1-3 months 3-6 months 6 months-1 year 1-2 years 2-5 years 5-10 years More than 10 years Total Sex (male/female) Weight(kg) range(mean) CPB time (minutes) range(mean) Aortic cross-clamp time (minutes) range(mean) Number of surgeries using CPB Number of surgeries without CPB

Number of Patients

20 99 126 102 243 175 138 97 1,000 603/397 1.4-73 (11.94) 35-245 (83) 18-195 (49) 912 88

Abbreviations: CPB, cardiopulmonary bypass.

(0.2-0.5 μg/kg/h) infusion or fentanyl infusion (1-2 μg/kg/h) was administered for overnight sedation and analgesia up to 12 hours and later continued with parenteral ketorolac. Forty-five (5.1%) patients required reintubation within 24 hours in the ICU. Of these 45, 15 were reintubated for surgical re-exploration within 4 hours and 16 for diaphragmatic plication for diaphragmatic palsy within 12 hours. All 15 of those upon whom an operation was performed for bleeding and 14 of 16 upon whom an operation was performed for diaphragmatic palsy were extubated in the ICU after observation and stabilization; while 2 of those upon whom an operation was performed for diaphragmatic palsy died with sepsis and were never extubated. One patient was reintubated because of tachyarrhythmia; whereas 7 were reintubated because of congestive heart failure, 4 for sepsis and 2 for ventricular dysfunction. The incidence of extubation in the OR increased as the age increased (Table 3). Forty percent of the neonates were extubated in the OR, whereas the rate of extubation in the OR increased with increasing age. Of the 129 patients who were not extubated in the OR, the authors analyzed the factor responsible for not proceeding with the extubation in the OR (Table 4). Seventeen patients were never extubated, and they died on a ventilator, whereas 112 patients subsequently were extubated in the ICU. Low oxygen tension was a responsible factor in 48 patients for not extubating them in the OR. Seventeen patients had left ventricular dysfunction requiring a high dose of inotropes, and 33 patients needed observation for bleeding, as surgeons were concerned about hemostasis, of whom 11 patients were redo-sternotomy patients. The sternum was kept open in another 23 patients because of either left ventricular dysfunction or a respiratory compromise upon approximating the sternum leading to high airway pressure, desaturation, and eventual hemodynamic instability. Eight patients were not extubated because of the patient’s native anatomic considerations that needed observation in the ICU. Out of these, 4 patients had narrowing of the branch pulmonary artery in whom pulmonary artery plasty was not done, but it needed observation for differential lung flow; 2 patients after total

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GARG ET AL

Fig 1.

A flow chart of the outcome in the study group.

correction of TOF required observation for increased pulmonary blood flow due to additional residual muscular VSD. In these patients, the surgeon felt that there was no need for surgical intervention. All of these patients were extubated in the ICU without surgical re-intervention. Another 2 patients, both neonates, were shifted to the ICU because 1 of them underwent coarctation of the aorta repair, and he had to be assessed for the need to do balloon aortic valvotomy, as he had congenital bicuspid aortic valve, and the other patient with VSD and coarctation of the aorta also underwent coarctation of the aorta repair, and VSD was not closed. Both these patients were extubated in the ICU without any intervention. Table 5 shows the details of high-risk patients depending on multiple variables like age, presence of Down’s syndrome, complexity of the lesion, and preoperative PAH . Sixty percent to ninety percent of these high-risk patients were extubated in the OR without any adverse event related to extubation. The data of the SG were compared with BSG, and the impact on resource utilization due to extubation in the OR is shown in Table 6. The ICU stay was significantly less in the study group (2.56 ⫾ 1.84 v 5.4 ⫾ 2.32 days, p o 0.0001) as compared to before-study group (BSG). The number of patients in the ICU (34.76 ⫾ 3.19 v 59.98 ⫾ 4.92, p o 0.0001) and the number of patients on a ventilator (5.1 ⫾ 1.24 v 24.5 ⫾ 2.88, p o 0.0001) on a daily basis were significantly fewer in the study group, reflecting a positive impact on resource utilization. None of the patients had bradycardia or hypotension following caudal administration of dexmedetomidine. The mortality rate in the study population was 3% (30/1,000), which is similar to the authors’ institutional mortality rate of 3% to 4%. Out of these, 17 patients were never extubated, whereas 13 patients died after extubation, 9 of whom were extubated in the OR and 4 in the ICU. None of the 9 patients extubated in the OR died because of early extubation, 2 died of sepsis after re-intubation because of diaphragmatic palsy, 1 following AVCD repair, and 1 after bi-directional Glenn shunt. Three

patients died of sepsis because of flaring of a preoperative infection in spite of preoperative antibiotic treatment, 1 after VSD closure, and 2 following B-T shunt. Three patients died of congestive heart failure, 1 following REV procedure, and 2 after total correction of TOF. One patient died of low cardiac output following a large ventricular septal defect closure. DISCUSSION

The management of pediatric cardiac surgery has improved significantly in the past few years due to improvements in surgical skills, perfusion technique, anesthetic management, and postoperative care.6 The use of high-dose narcotic anesthesia during the perioperative period had been recommended to blunt the stress response during surgery, avoid pulmonary vasoconstriction and hemodynamic instability related to endotracheal suctioning, improve cardiovascular stability and improve the outcome in these patients.1–4 This led to the practice of continued ventilation, sedation, and occasional intermittent paralysis in the postoperative period.3,4 Similar practice of continuing ventilation, sedation, and paralysis was followed in the authors’ institution. The potentially deleterious effects of mechanical ventilation include laryngotracheal trauma, kinking of the endotracheal tube, mucus plugging, accidental extubation, oversedation, and increased incidence of ventilator-associated pneumonias. Pulmonary hypertensive crisis can be triggered during tracheal suctioning, and positive-pressure ventilation increases the pulmonary vascular resistance and may lead to reduced pulmonary blood flow.5,21–23 Early extubation can help in reducing many of these complications24 and may improve cardiac performance by increasing stroke work and cardiac output after cardiac surgery.25 Early extubation also helps in reducing ICU stay as well as better utilization of resources.13–17 Considering the benefits of early extubation and the literature supporting the

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EXTUBATION IN CHILDREN AFTER CARDIAC SURGERY

Table 2. Details of Procedures Performed Along With Percentage of Patients Extubated in the OR and Mortality

Procedure

Total correction for TOF VSD closure ASD closure ASO AVCD repair Partial AVCD repair TAPVC repair Truncus arteriosus repair Rastelli procedure Fontan REV procedure B-T shunt Bi-directional Glenn shunt PA banding ALCAPA AP window closure PDA ligation Coarctation of aorta repair Double switch operation VSD closure and coarctation of aorta repair VSD closure and aortic valve repair Senning procedure Ross procedure Miscellaneous Total

Number of Patients Extubated

Percentage (%) of Patients

Mortality Among OR Extubated/Not OR

in the OR/Total Patients

Extubated in the OR

Extubated/ Total (Total Number of Patients in SG)

170/186 268/292 130/130 13/34 27/34 13/13 35/53 3/4 11/13 8/10 6/7 61/75 18/20 16/17 1/1 3/8 26/27 11/13 1/1 5/5 5/7 4/5 1/3 35/42 871/1000

91.39 91.78 100 38.23 79.41 100 66.03 75 84.61 80 85.71 81.33 90 94.11 100 37.5 96.29 84.61 100 100 71.42 80 33.33 83.33 87.1

2/0/2 2/1/3 0/6/6 1/2/3 0/3/3

1/1/2 2/3/5 1/0/1

0/1/1 0/1/1

0/1/1 0/2/2 9/21/30 (1000)

Abbreviations: ALCAPA, anomalous origin of left coronary artery from pulmonary artery; AP, aortopulmonary; ASD, atrial septal defect; ASO, arterial switch operation; AVCD, atrioventricular canal defect; B-T, Blalock-Taussig; OR, operating room; PA, pulmonary artery; PDA, patent ductus arteriosus; REV, reparation a I’Etage ventriculaire; SG, study group; TAPVC, total anomalous pulmonary venous connection; TOF, tetralogy of Fallot; VSD, ventricular septal defect.

feasibility of extubation in the operating room in pediatric cardiac patients, including patients at a high risk for a complicated postoperative course, the authors adopted a policy of considering extubation in the operating room for all children undergoing cardiac surgery except those excluded according to the exclusion criteria. The next challenge of changing from a routine of overnight ventilation to extubation in the OR required a multidisciplinary coordinated approach, in which the surgeon, anesthesiologist, perfusionist, intensivists, ICU staff nurses, and respiratory therapists work together in a coordinated manner. It was necessary to revise some protocols, and everyone involved in the care of the patient was made aware of the new protocol. This study reviewed the authors’

experience with extubation in the OR and showed that 87% of the entire group of patients were extubated safely in the OR. To make an attempt to extubate patients in the OR, the anesthesia technique was modified. Anesthesia was induced and maintained with an inhalation technique, and the use of narcotics was limited to no more than 5 μg/kg of fentanyl. After induction, morphine and dexmedetomidine were administered in a single-shot caudal epidural technique. Caudal opiates have been shown to provide superior analgesia and decreased need for supplemental postoperative analgesia,26,27 blunt the stress response to surgery and CPB,28–30 shorten time to extubation,31,32 and improve pulmonary function.33 In addition, dexmedetomidine, an alpha-2 agonist, also provides

Table 3. Age-wise Details of Patients Extubated in the OR in the Study Population Number of Patients Age

Less than 1 month 1-3 months 3 months-1 year 1-3 years 3-5 years 5-10 years More than 10 years Total

Extubated in OR/Total Number

Percentage (%) of Patients Extubated in OR

8/20 69/99 195/228 288/313 99/105 128/138 84/97 871/1000

40 69.7 85.5 92.01 94.28 92.75 86.59 87.1

Abbreviation: OR, operating room.

Table 4. Showing Factor Responsible for Deferring Extubation in the OR Factor Responsible for Not Extubating in the OR

Low PaO2 Open sternum LV dysfunction requiring high dose inotropes Observe for bleeding Patient’s native anatomic concern

Number of Patients Not Extubated in OR (Total 129)

48 23 17 33 8

Abbreviations: PaO2, partial pressure of oxygen; LV, left ventricle; OR, operating room.

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Table 5. Details of High-risk Category of Patients Based on Multiple Variables Number of Patients Extubated in High-Risk Category

the OR/Total Patients (Percentage)

TAPVC, age o1year, Severe PAH AVCD with Down's syndrome, severe PAH

22/37 (59.5%) 8/10 (80%)

AVCD without Down’s syndrome, severe PAH

19/24 (79.1%)

VSD , age o1 year, severe PAH Rastelli procedure Total correction for TOF , age less than 1 year ASO Neonate 1-3 months 3-6 months 6-12 months 1-2 years Truncus arteriosus repair 1 month 2 months 9 months 10 months

99/113 (87.6%) 11/13 (84.6%) 16/20 (80%) 4/9 5/16 3/4 1/3 0/2

(44.4%) (31.2%) (75%) (33.3%) (0%)

1/1 1/1 1/1 0/1

(100%) (100%) (100%) (0%)

Re-intubation/Mortality

2 re-intubated for diaphragmatic palsy/ no mortality 1 re-intubated for diaphragmatic palsy/same patient died of sepsis 1 re-intubation for surgical re-exploration for bleeding/no mortality 4 re-intubations: 1 each for LV dysfunction, diaphragmatic palsy, tachyarrhythmia, bleeding/1 mortality due to sepsis No re-intubation/no mortality No re-intubation/no mortality 2 re-intubations for diaphragmatic palsy, no mortality

No re-intubations, no mortality

Abbreviations: ASO, arterial switch operation; AVCD, atrioventricular canal defect; LV, left ventricle; OR, operating room; PAH, pulmonary artery hypertension; TAPVC, total anomalous pulmonary venous connection; TOF, tetralogy of Fallot; VSD, ventricular septal defect.

sedation and analgesia via the caudal route34 and potentiates the analgesia provided by opiates.35–37 This is very helpful in spontaneously breathing patients in the ICU as part of an anesthetic regimen suited for early extubation.38 Similar results were observed in this study with the use of caudal morphine and dexmedetomidine, which helped in early extubation and provided analgesia and sedation in the postoperative period. The authors observed analgesia and sedation in the postoperative period for approximately 12 hours from the time of administration of caudal analgesia, after which they administered additional analgesia prophylactically although the effect of caudal morphine may last up to 24 hours. Intensivists assessed the time to initiate supplemental postoperative analgesia in the ICU. In addition, ultrafiltration,39–41 both conventional (CUF) and modified (MUF), was used to remove priming and cardioplegia volume, reduce concentration of inflammatory mediators, avoid postoperative edema, decrease extravascular lung water, and, therefore, potentially improve pulmonary compliance and cardiac function. A good surgical repair followed by assessment with the TEE helped to proceed with the decision to extubate in the OR. The various factors that prevent early extubation in children following surgery for CHD mentioned in various retrospective studies are age,8,9,11,42 complexity of the surgery,10,11 long CPB time,11,42,43 higher inotrope use,11 postCPB low oxygen tension,43 pulmonary hypertension,42,44 and Down’s syndrome.44 The authors reported the results of the prospective study in which every patient was a candidate for extubation in the OR. The factors that led them to defer extubation in the OR were low oxygen tension, the use of high inotropes secondary to ventricular dysfunction, and an open sternum. Although the incidences of low oxygen tension and an open sternum were higher in neonates and infants between

1 month and 3 months, which may be manifestations of increased inflammatory response with generalized edema, decreased lung compliance and acute lung injury, the authors were able to extubate 40% of neonates and 70% of infants between 1 month and 3 months who underwent complex surgical repairs like TAPVC, arterial switch operation, Senning procedure, and truncus arteriosus repair without any unfavorable incident related to extubation as similarly reported by Heinle et al.48 These patients had good gas exchange and good cardiac function, and primary closure of the sternum was achieved in them. Although age, complexity of the surgery, and longer CPB time are important factors to consider, these did not prevent extubation in the OR. Left ventricular dysfunction requiring a high dose of inotropes remained an important factor that prevented the authors from deciding to extubate in the OR. The presence of preoperative PAH has been perceived as a contraindication for early extubation, but the authors found that patients with preoperative PAH could be extubated safely in the OR as supported by the literature.10 In the authors’ study, patients with MPAP/MSAP less than 1 were extubated in the OR, and patients with MPAP/MSAP more than 0.7 were given oral sildenafil via a nasogastric tube in the ICU. These patients were monitored in the postoperative period with serial echocardiography for assessment of MPAP and right and left ventricular function. None of the patients with PAH, as shown in Table 5, was reintubated because of pulmonary artery hypertension or pulmonary crisis in the postoperative period. The authors felt that the triggering factors for increase in pulmonary artery pressure or pulmonary hypertensive crisis were pain and suctioning through the endotracheal tube, which eliminated analgesia and early extubation, respectively. None of the patients had pulmonary hypertensive crisis in the study.

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Table 6. Comparison Between Study Group (SG) and Before Study Group BSG). Value ( Mean ⫾ SD) Variable

Number of patients in ICU (daily) Number of patients on Ventilator (daily) ICU Stay (in days)

BSG

SG

59.98 ⫾ 4.92 24.5 ⫾ 2.88 5.4 ⫾ 2.32

34.76⫾ 3.19 5.1 ⫾ 1.24 2.56 ⫾ 1.85

P value

0.0001 0.0001 0.0001

Abbreviations: ICU, intensive care unit.

Cardiovascular surgery is the most common cause of acquired diaphragmatic palsy. Patients undergoing surgery for CHD have a varying incidence of diaphragmatic palsy depending on the type of surgical procedure.45,46 In the authors’ study, 16 patients were re-intubated because of diaphragmatic palsy within 12 hours. They felt that extubation in the OR helped in early diagnosis and treatment of this condition. This is beneficial in children less than 1 year old when diaphragmatic plication is electively planned in the authors’ institution. The authors observed that in their control group, the diagnosis of diaphragmatic palsy was delayed up to 48 to 96 hours after multiple attempts of weaning failed. In their study, 14 patients had good outcome after diaphragmatic plication. The remaining 2 patients could not be weaned. (One of them had bilateral diaphragmatic palsy.) Both of them died of sepsis. The important considerations in the decision to extubate in the OR are postoperative pain control with sedation and without respiratory depression. The various neuraxial interventions that have been used in pediatric cardiac anesthesia include thoracic epidural, caudal epidural, and subarachnoid approaches administering single bolus or continuous infusion of local anesthetics, opioids, and α2-agonists.34 Most have shown a definite benefit in outcome, be it attenuation of surrogate markers of stress response, hemodynamic stability, time to extubation or length of stay in the intensive care unit.26–33, 35–37 Both morphine27 and dexmedetomidine34 have been shown to provide good analgesia and sedation through the caudal route. Alpha2-adrenoceptor agonists have been used as an adjuvant to regional anesthesia. Dexmedetomidine is a highly specific and selective α2-adrenoceptor agonist with a high ratio of α2/α1 activity (1620:1 as compared with 220:1 for clonidine). Dexmedetomidine has detrimental cardiac effects like bradycardia and decrease in systemic vascular resistance, especially in right-toleft shunt patients after intravenous administration. Although the authors did not experience any of these side effects with caudal administration, they were prepared to manage them with the help of atropine and phenylephrine. The addition of dexmedetomidine with morphine has multiple benefits as it has been shown to increase the efficacy and duration of postoperative analgesia and sedation and to decrease the stress response to surgery.34 In the authors’ study, they observed that sedation and analgesia continued for at least 6 to 8 hours postoperatively. The reintubation rate in the study was 5.1%, which was similar to various other studies,6,11,48 although they included all high-risk patients, indicating the safety of this approach. The mortality in this study was similar to the authors’ institutional mortality of 3% to 4% before starting this study, which proved the safety of extubation in the OR .

Many studies have shown that early extubation and fasttracking result in shorter ICU and hospital stay leading to reduced costs.8,10,12,17,48–50 In the authors’ study, they did not calculate the cost benefit but compared length of ICU stay in the SG with the BSG. They also compared the difference in resource utilization, as assessed by the number of patients in the ICU and number of patients on the ventilator on a daily basis in the 2 groups. They found significantly favorable outcomes in all 3 variables. This helped in better resource utilization, both in terms of manpower and consumables, which indirectly reduced overall costs. The limitation of the present study was of making a comparison between the OR extubated group utilizing neuraxial analgesia to elective sedation and the paralysis group with high intraoperative dose narcotics as the control group. Resource utilization may be the same in the OR extubation group and early extubation group (within 6 hours in the ICU) utilizing the same anesthesia technique, but in the authors’ institution, the practice of precluding weaning in the nightshift due to workforce constraints and a large number of patients in the ICU led to sedation and ventilation until the next morning. This led to the trial of practicing OR extubation in which a dedicated anesthesiologist was available for weaning, observation, and stabilization before transferring to the ICU. When historic controls are used to compare the outcome, there may be influence of multiple factors within the observed time period, which often extends over years, which may affect the cost benefit and ICU length of stay. The authors acknowledge this limitation, but since their data were collected from a large number of patients in a very short time period due to a highvolume center, it was much less likely that factors other than early extubation might have impacted the outcome. Ideally, a well-designed prospective randomized study of adequate size is required to prove the cost benefit and shorter ICU stay. Lawrence et al17 showed cost reduction and shorter length of stay of patients after implementing fast-tracking to a nationwide cohort in the same time period. Another limitation of the authors’ study was the non-blinding nature of the study, which they felt to be difficult to design, considering the patient care and safety. This leads to potential for bias and motivation of the team to move patients up and out of the ICU. However, the same standard treatment according to the existing practice of the ICU was followed for transferring the patients out of the ICU to the ward; it can be assumed that this bias is nullified, but this limitation may be overcome by predetermined criteria for weaning and transfer from the ICU to the surgical ward. Further limitation of the study was that the authors had not done direct cost benefit analysis or the

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GARG ET AL

parental satisfaction survey, which they plan to do in the next study. Another important point in the present study was its applicability and the need to extubate in the OR to the practice of other centers that have a smaller number of patients, and the patients could be extubated early in the ICU. The authors feel that if the early extubation within 2 to 4 hours in the ICU can be practiced, then the re-intubations for re-exploration for surgical bleeding and diaphragmatic palsy can be avoided. The important message the authors want to convey is that the perioperative course can be planned in such a way that many patients can be extubated safely at the completion of the surgery either in the OR or early in the ICU, depending on the applicability in that particular center, instead of planning

elective ventilation. At the completion of the surgery, if it is felt that it is not safe to extubate the patient in the OR or early in the ICU, then the patient can be sedated and ventilated until stabilized in the ICU. To conclude, extubation in the OR after surgery for CHD was successful in all patient groups and procedures. The main factors responsible for deferring the decision to extubate were low oxygen tension and ventricular dysfunction. The authors concluded that every patient should be approached as a potential candidate for extubation in the OR and managed with a multidisciplinary coordinated approach with vigilant monitoring in the postoperative period so that there can be a safe and more positive convalescence for the patient and the family, better resource utilization for the hospital, and, indirectly, reduced costs.47

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