ABSTRACT
 

Introduction:  Early extubation after cardiac operations is an important aspect of fast-track cardiac anesthesia. In order to reduce or eliminate the adverse effects of prolonged ventilation, the concept of early extubation in pediatric patients has been examined at our institution.

Material and methods: To allow rapid emergence from anesthesia post cardiac surgery, low-dose opioids, supplemented with continuous propofol infusion and low concentration of inhaled agent was used. Intercostal nerve block was used in thoracotomy operations. Contraindications to early extubation were: cardiopulmonary bypass (CPB) > 2.5 hours, hemodynamic instability, uncontrolled bleeding, severe pulmonary hypertension and congestive heart failure.

Results: Eighty-two consecutive patients were reviewed. The age range was 6 months – 14 years with mean of 3.3 years. Closed cardiac procedures were performed in 15 (18.3%) patients, and operations with Cardio-pulmonary bypass in 67 (81.7%) patients. No patient required re-intubation during the first 24 hours after operation. One patient was re-intubated 48 hours after extubation for sputum retention. There was no mortality, and the incidence of perioperative morbidity was low.

Conclusion: Early extubation after pediatric cardiothoracic operations can be achieved safely, and is possible in the majority of such patients. Heart Views 2007; 8(2)40-42.© Gulf Heart Association 2007.

Key Words: ¨ Early extubation ¨ pediatric anaesthesia ¨ postoperative management



Introduction


  
     With the escalating number of patients requiring cardiac surgery, efficient use of limited facilities by fast-track cardiac anesthesia and efficient resources utilization resulted in the adoption of early tracheal extubation techniques in cardiac surgery1,2. Early extubation has been documented in adults3 and children4,5 to avoid the potentially deleterious effects of mechanical ventilation such as laryngotracheal trauma, barotrauma, pneumothorax, mucus plugging, incorrect positioning or kinking of endotracheal tube, accidental extubation, infection and pulmonary hypertensive crises secondary to manipulation or suctioning of the endotracheal tube6. In addition, the postoperative use of sedative and analgesic drugs, to facilitate tolerance of the endotracheal tube, may prolong the duration of intubation6.

     In order to reduce or eliminate the adverse effects of prolonged intubation, the concept of early extubation (in the operating room, or within one hour in intensive care unit) in pediatric age group was examined at our institution.


Materials and methods


     
    This is a prospective study of 82 consecutive pediatric patients undergoing cardiothoracic operations between October 2005 and February 2007 at the Queen Alia Heart Institute in Amman, Jordan. Complex congenital heart diseases, CPB > 2.5 hours and neonates were excluded from the study. The essential aspects of early extubation included: choice of anesthetic agents, hemodynamic stability and good postoperative analgesia. Midazolam was used as a premedication at 0.07 – 0.1 mg/kg intravenously, 30 – 50 minutes before induction of anesthesia.
The patients were induced with midazolam 0.1 mg/kg, fentanyl 5 – 10 mcg/kg and pancronium 0.1 mg/kg. Maintenance anesthesia consisted of low dose fentanyl at 1 – 2 mcg/kg, and low concentration of inhaled agents as clinically indicated, along with midazolam at 0.1mg/kg and propofol infusion of 2 – 5 mg/kg/hour. Muscle relaxants were not used after the first dose, unless there was patient movement.

    Meticulous myocardial protection during aortic cross clamp is a necessary prerequisite for stable myocardial function after CPB. In the absence of severe pulmonary dysfunction, hemodynamic instability, excessive bleeding, or concerns regarding the airways, the patient’s neuromuscular blockade was reversed at the conclusion of operation and the patient was allowed to be awake. Upon evidence of adequate ventilatory effort and satisfactory gas exchange, the patient was extubated, either immediately in the operating room, or within one hour in intensive care unit (ICU). Post operative vital signs, electrocardiogram, x-ray chest, blood gases and signs of low cardiac output were monitored in ICU.

    Postoperative pain was managed using either fentanyl at 0.1 mcg/kg/hour in incremental doses, meperidine (pethidine) 0.5 – 1 mg/kg intramuscular or Acetaminophen/diclofenac suppositories as needed. All patients with lateral thoracotomy incision received intercostal nerve block. In the ICU, inotropic medications and oxygen were provided as needed.


                                       

Results


  
     
     Of the 82 patients, 61 (74%) were males and 21 (26%) were females. The age range was 6 months – 14 years with mean of 3.3 years. Closed cardiac operations were performed in 15 (18.2%) patients that included: Blalock-Taussig shunt in 10; division of PDA in 4; and division of vascular ring in one patient. Sixty seven (81.7%) patients were done under CPB, and this group included: ventricular septal defect (VSD) in 20; VSD with atrial septal defects in 20; tetralogy of Fallot in 15; double outlet right ventricle in 8; and mitral valve replacement in 4 patients.
 
   The CPB time ranged from 27 – 60 minutes with mean of 45.7 minutes and the aortic cross clamp time ranged from 15 – 35 with mean of 25.8 minutes. The age range for these patients was 1 – 14 years with mean of 3.9 years. The average total operation time for all cases ranged from 65 – 156 minutes with mean of 122 minutes.

    All patients continued to have normal sinus rhythm in ICU, with evidence of right bundle branch block in the right ventriculotomy patients.

    Fourteen (17%) patients didn’t require postoperative analgesia, while 54 (66%) patients required paracetamol/diclofenac suppository. Twenty seven (33%) patients required meperidine injection and 5 (6%) required fentanyl and paracetamol/diclofenac suppository. None of the patients needed re-intubation during first 24 hours post extubation in ICU, while one patient was re-intubated after 48 hours due to retention of secretions. There was no mortality, and the incidence of perioperative morbidity was 3 (3.7%).

      
         
 
Discussion


      Ventilation of postoperative patients undergoing cardiac operations has been a standard practice for the past three decades7. Initially, it was justified because of the high incidence of respiratory insufficiency, low cardiac output state after cardiac operations and the use of high-dose anesthesia techniques7. This practice has been a driving force for fast-tract cardiac anesthesia3,8. It was realized that patients who got early extubation, had shorter ICU and hospital stay and therefore lower cost of care10.

    The potential benefits of early extubation include cost saving7, lower nursing dependency, reduced airway and lung trauma11, improved cardiac output and renal perfusion with spontaneous respiration12 and reduced stress and discomfort of endotracheal suctioning and weaning from the ventilator13. The opponents to early extubation argue that the immediate perioperative period is the most critical for myocardial ischemia, hemodynamic instability and sympathetic nervous system activation14. The concern about immediate or early extubation is the possibility of reintubation and ventilation for respiratory failure in the immediate postoperative period. The low incidence of perioperative morbidity in our series suggests that early extubation methodology in post operative cardiac patients is safe and effective.

    Neonates and infants were excluded from the study because they are at a tremendous disadvantage when it comes to their base line respiratory function. Neonatal lungs behave physiologically like geriatric emphysematous lungs in that they are overly compliant and prone to premature airway closure15. The respiratory muscles of infants are less endurance oriented and less fatigue resistant than adults, and thus are prone to muscle fatigue. Respiratory control is also immature and do not respond to hypoxia and to hypercarbia effectively as in adults. The immature myocardium of neonates is more susceptible to ischemia, as demonstrated in some studies, and it recovers slowly from the insult of surgery and cardiopulmonary bypass16.

    In this series, no patient required reintubation in the first 24 hours after operation. The probability of re-intubation will be increased if the patients are hemodynamically unstable, cold, hypovolemic, or required considerable opiate medications15. The challenge is to have a stable, warm, hemodynamically stable and awake patient at the completion of operation, which is possible in the majority of patients undergoing such cardiac operations

         

Conclusion


   
        Early extubation after pediatric cardiothoracic operations can be safely achieved in selected patients provided that all the parameters are indicative of safe extubation. The younger the patient, the more difficult the decision of early extubation will be. But excluding neonates and early infants would make it an easier decision to take, provided that the above mentioned policy is followed.¨


References:


1. Cheng DCH: fast-track cardiac surgery. Economic implications in posterative care. J Cardiothorac Vasc Anesth 12:72-79, 1998.

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

3. Karski JM: Practical aspects of early extubation in cardiac. J Cardiothorac Vasc Anesth 9:30-33, 1995.

4. Barash PG, Lescovich F, Katz JD, Talner NS, Stansel HC: Early extubation following Pediatric Cardiothoracic Operation: A Viable Alternative. Ann Thorac Surg Vol 29 No 3, 1980.

5. Schuller JL, Bovill JG, Nijvel A, and Patrick MR, Marcelletti C: Early Extubation of the Trachea after Open Heart Surgery for Congential Heart Disease. A review of 3 years experience. Br. J. Anesth. 56:1101, 1984.

6. Heinle JS, Diaz LK, and Fox LS: Early Extubation after Cardiac Operation in Neonates and Young infants. J Thor Cardiovac Surg 1997; 114.

7. Shapiro B, Lichtenthal P. Inhalational-based anesthetic techniques are the key to early extubation of cardiac surgical patient. J Cardiothorac Vasc Anesth 1993; 7: 135-6.

8. Higgins TL, Safety issues regarding early extubation after cornary artery bypass surgery. J Cardiothorac Vasc anesth 9:24-29, 1995.

9. Chong J, Pillai R, Fisher A, Grebenik C, Sinclair M, Westaby S, Cardiac surgery: moving away from intensive care. Br Heart J 1992; 68:430-3.

10. Chong J, Grebenik C, Sinclair M, Fisher A, Fillai R, Westaby S, The effect of a cardiac surgical area on the timing of exrubation. J Cardiothorac Vasc Anesth 1993; 7:137-41.

11. Quash A, Loeber N, Freeley T, et al. Post respiratory care; A control trial of early and late extubation following coronary artery hypass grafting. Anesthesia 1980; 52:135-41.

12. Higgans T. Pro: early extubation is preferable to late extubation in patient following coronary artery surgery. J Cardiothorac Vasc Anesth 1992; 6:488-93.

13. Colin F. royse, FANZCA, Alistair G. Royse, FRACS, and Paul F. Soeding, FANZCA. Routing immediate extubation after cardiac operation: A review of our first 100 patients. Ann Thorac Surg 1999; 68: 1326-9.

14. Siliciano D. Con: early extubation is not preferable to late extubation in patients undergoing cardiac surgery. J Cardiothorac Vasc Anesth 1992; 6: 494-8.

15. Motoyama EK. Respiratory physiology in infants and children in: Simth's anesthesia for infants and children. Mosby, Philadelphia, 1996.

16. Casteneda AR, Jones RA, Mayer et al. Perioperative care In: Cardiac surgery of the neonates and infant. WB Saunders, Philadelphia, 1994..


 

Two horses Two horses were carrying two loads. The front Horse went well but the rear Horse was lazy. The men began to pile the rear Horse’s load on the front Horse; when they had transferred it all, the rear horse found it easy going, and he said to the front Horse: “Toil and sweat! The more you try, the more you have to suffer.” When they reached the tavern, the owner said, “Why should I fodder two horses when I carry all on one? I had better give the one all the food it wants, and cut the throat of the other; at least I shall have the hide.” And so he did.                                                                                                           Fables                                                                                                           Leo Tolstoy, 1828-1910