2007 OPEN FORUM Abstracts
USING PROPORTIONAL ASSIST VENTILATION TO WEAN A PATIENT WITH SEVERE COPD: A CASE REPORT
M. Kragten1, J. Bard2, R. Hase1, M. Westley2
Introduction: Proportional Assist Ventilation (PAV) is advocated as a spontaneous mode of ventilation that allows the patient to maintain control of flow and volume throughout the respiratory cycle, regardless of the level of support desired. We used PAV to diminish dyspnea for a patient who had not responded favorably to any prior type of positive pressure ventilation.
Case Summary: A 68 year old male with HIV and severe COPD was admitted through our ED with progressive dyspnea. He was tachypneic (RR 40-60) with 100% O2 mask, temperature 40.2 C, BP of 202/103, and HR of 131. Breath sounds had diffuse wheezes with a prolonged expiratory phase. Blood gas during BiLevel ventilation by mask revealed respiratory acidemia, and the patient was intubated with an 8.0 ETT and ventilated using a Puritan Benett 840 machine set to AC 16, 600Vt, 100% and 5 PEEP. Pseudomonas was cultured from sputum obtained by bronchoscopy. The initial peak airway pressures (PAW) were 25 cm H2O with the patient sedated and paralyzed; however, despite the use of bronchodilators and steroids. The PAW increased to upper 40s as sedation wore off. The second ICU day, a Spontaneous Breathing Trial (SBT) was attempted but lasted only 5 minutes secondary to tachypnea, tachycardia, air hunger, and hypertension. Sedation continued to be required to manage the patient’s air hunger, tachypnea, and ventilator dysynchrony, in spite of multiple attempts to improve the patientâs work of breathing by modifying set flow, volume, mode, and/or adding pressure support. Finally, PAV was instituted at 70% support. The patient’s dyspnea and dysynchrony immediately improved and stabilized, and maintained within acceptable levels over the next 24 hours. Only one episode of dyspnea briefly required the PAV support level to be increased to 80%, which was returned to 70% following light sedation and within a few hours decreased again to 60%. He then remained comfortable on PAV for two more days. After passing a standard spontaneous breathing trial he was extubated on ICU day 4.
Discussion: PAV provided comfortable ventilation for a patient who previously had increased WOB and air hunger unresponsive to other ventilatory options. Sedation requirements decreased and we observed a smooth transition to routine spontaneous breathing trials and eventual extubation. PAV may be a useful ventilation adjunct for tachypneic, dyspneic COPD patients when other ventilation modes do not provide adequate patient comfort.