The Science Journal of the American Association for Respiratory Care

1996 OPEN FORUM Abstracts

TRACHEAL GAS INSUFFLATION (TGI) AS AN ADJUNCT TO WEANING IN VENTILATOR DEPENDENT INDIVIDUALS: A STUDY DURING RAPID SUPPORT WITHDRAWAL.

J. Hoyt, A McKibben, AB Adams, F Indihar, JJ Marini, A Nahum. University of Minnesota, Bethesda Lutheran Medical Center and St. Paul Ramsey Medical Center. Mpls./St. Paul, MN.

TGI flushes the deadspace free of CO_{2} from the catheter tip to the airway opening. This effect may decrease minute ventilation requirements of ventilator dependent individuals and allow them to tolerate less or no ventilator support. To our knowledge, TGI has not been evaluated as a technique to assist weaning from the ventilator. In a chronic ventilator unit, we obtained consent for such an assessment from 10 individuals deemed ventilator dependent after multiple unsuccessful weaning attempts. Methods: Pressure support ventilation (PSV) was set to provide a tidal volume of 10 mL/Kg. Pressure support level was then reduced by 15% every 15 minutes until intolerance developed. This served as a weaning "stress test" to assess length and ease of ventilator support withdrawal. Each patient was randomized to begin either TGI or no TGI, and to cross over to the other limb after an hour of rest with full ventilator support. Monitoring during the study included airflow, airway pressure, esophageal pressure, respiratory inductance plethysmography, oximetry, capnography, and EKG. Intolerance to a reduction in PSV was assessed by preestablished criteria. Expiratory TGI was delivered at 10 L/min (blended to the F_{1}O_{2} of the ventilator) with the catheter positioned 1 cm above the carina. Results: With TGI, the subjects tolerated reduction from full support for a mean of 67.2 ± 26.7 minutes while tolerating 60.5 ± 19.2 minutes during the control limb (p=0.29). One patient with a narrowed upper airway (confirmed by bronchoscopy) demonstrated intolerance within 21 minutes of TGI (compared to 44 minutes during the control limb) by increased breathing frequency. During TGI, all patients inspired part of their tidal volume from TGI gas flow prior to triggering the ventilator. Several patients took shallow breaths entirely from TGI gas flow without triggering the ventilator. Conclusions: Patients tolerated gradual withdrawal of ventilator support with TGI but their tolerance was not significantly different during PSV alone (without TGI). In some patients, TGI may impair ventilator triggering.

Reference: OF-96-184

You are here: RCJournal.com » Past OPEN FORUM Abstracts » 1996 Abstracts » TRACHEAL GAS INSUFFLATION (TGI) AS AN ADJUNCT TO WEANING IN VENTILATOR DEPENDENT INDIVIDUALS: A STUDY DURING RAPID SUPPORT WITHDRAWAL.