The Science Journal of the American Association for Respiratory Care

1999 OPEN FORUM Abstracts


Theresa Ryan Schultz, BA, RRT, CPFT, P/P Spec., H. Marc Watzman, MD, R. Lin, MD, R. Hales, BS, RRT, P/P Spec., S. Durning, BS, RRT, P/P Spec., L. Napoli, BS, RRT, RPFT, P/P Spec., L. Corbley, AS, RRT, P/P Spec., T. Dominquez, MD, R. I. Godinez, MD, PhD. The Children's Hospital of Philadelphia, Philadelphia, PA

Introduction: Mechanical ventilation remains a critical component in the management of respiratory insufficiency. Weaning from mechanical ventilation accounts for as much as 40% of the time a patient receives mechanical ventilation.1 Traditionally, this process has required the physicians presence to strategically manage and monitor the patient's response to the reduction of ventilatory support. A patient's recovery of respiratory function, either from resolution of the patient's illness or a reduction in anesthetic effects in post-operative patients, is often unpredictable. With other clinical responsibilities, the physician may not be available at such times. Delays in weaning from mechanical ventilation may lead to unnecessary discomfort in the intubated patient. Increased risk of complications related to tracheal intubation and mechanical ventilation such as tracheitis, volu/barotrauma, subglottic stenosis, and vocal cord paralysis may occur. We hypothesize that a protocol-directed weaning strategy results in a decrease in total mechanical ventilation time with no increase in morbidity when compared to physician-directed weaning of pediatric patients.

Methods: This was a prospective, randomized control trial. Patients were randomized to one of two groups at the onset of mechanical ventilation or upon admission to our Intensive Care Unit if mechanical ventilation was initiated prior to admission. Protocol-directed (study) and physician-directed (control) patients were recruited from the pediatric intensive care unit and cardiac intensive care unit. Patients were enrolled if they received mechanical ventilation via tracheal intubation at any time during their intensive care unit hospitalization. Initiation of weaning began when: FiO2 < 0.6, PEEP <8 cm H20, total (patient + ventilator) respiratory rate (RR) < 1.5 ´ predicted value for age using the mean value, ratio of actual VE to predicted VE > 2, pH > 7.35 when available, and Sp02 was within normal limits as established for that patient. Criteria for beginning weaning also included maximum inspiratory force -20 cm H20, and spontaneous initiation of breath for ten consecutive minutes. When these criteria were met, the Respiratory Care Practitioner reduced the amount of pressure support administered to the least level of pressure support necessary to maintain the patient's RR less than or equal to 1.5 times the mean predicted RR for age. The study endpoint was reached when pressure support was £ 5 cm H20 with PEEP £ 5 cm H20. Exclusion criteria included hyperventilation of head-injured patients and marginal cardiac function.

Results: 55 patients have been enrolled to date: 30 male, 25 female. Age in years averaged 6.7. 12 hour Prism III scores averaged 5.7 +/- 5 for study patients and 7.4 +/- 6.1 for control patients. 24 hour Prism III scores averaged 6.7 +/- 5.4 for study patients and 8.3 +/- 7.4 for control patients. Prism III at 12 and 24 hours were not statistically significant between groups.

Protocol-Directed Physician-Directed
Time prior to weaning (hours) 58.5 +/- 115.9 (median=12) 122.5 +/- 249.3 (median=13)
Duration of weaning (hours) * 10.5 +/- 25.4 44.5 +/- 67.4
Duration of FiO2 >.4 (hours) 2.6 +/- 4.2 34.9 +/- 163.6
represents mean data +/- standard deviation *indicates p-value <.05

Conclusions and Recommendations: Protocol-Directed weaning seemed to be valuable in the weaning of our ICU patients. Utilizing a protocol-directed plan of care can shorten weaning time.

1. Esteban A, Aslfa I., Ibanez J, Benito S, Tobin MJ: Spanish Lung Failure Collaborative Group. Modes of mechanical ventilation and weaning: a national survey of Spanish hospitals. Chest 1994:106: 1188-93.