The Science Journal of the American Association for Respiratory Care

2010 OPEN FORUM Abstracts

USE OF CAPNOGRAPHY TO ASSURE AIRWAY PATENCY DURING INHALED VASODILATOR DELIVERY WITH NITRIC OXIDE FOR VASOREACTIVITY TESTING IN THE CARDIAC CATHERIZATION LAB

John T. Murphy1, Bryce Click1, Scott Wischmeyer1, Carl L. Rouch2; 1Respiratory Therapy, St Francis Hospital, Indianapolis, IN; 2Cardiovascular Care Center, St. Francis Hospital, Indianapolis, IN

Background: Cardiovascular labs (CVL) perform Vasoreactivity (VR) tests with inhaled nitric oxide (NO) and not IV nifetipine. IV pumps monitor vasodilator flow disruption. No routine method has assured airway patency for NO delivery to the lower airways required to elicit a response. With moderate sedation, hypoventilation, partial airway obstruction and apneas occur as patients breathe abnormally. This occurs by observation evidence and oximetry. With abnormal breathing, airway patency is uncertain; a VR response may not be verified, wasting expensive NO. Methods: EtCO2 monitoring via nasal interface sidestream device was used to alert for abnormal breathing conditions. RT used alarm events to improve airway status and breathing with verbal or tactile stimulation. Low RR was set to 7. Low and high EtCO2 was set to 30 and 50mmHg. Delivery of 40 ppm NO for 5 minutes occurred when ordered. Supplemental 02 flowrates needed were supplied via separate nasal cannula. Average sedation dose for comfort was 60 mg for fentanyl and 3 mg for midazolam. Results: RT used capnography to monitor 17 patients for VR testing in the CVL. NO delivery was supplied to those who had increased mean PA and qualifying wedge pressures. NO delivery assurance was monitored by RT observing normal and abnormal capnography waveforms. Limit violations for RR and EtCO2 alerted RT to stimulate drowsy patients to increase breathing efforts. If patients given 40 ppm NO for 5 minutes did not produce a 10 torr decrease in mean PA pressure, they were often given 80 ppm NO for 5 minutes. Capnograms were observed with EtCO2 and RR values compared to their baseline values. All cases exhibited abnormal capnograms during testing. The average RR drop was 9 bpm or 48%. The average EtCO2 drop was 6 mmHg or 19% and increases averaged 10%. Hypoventilation, bradypnea, partial obstructions, or apneas were abnormal breathing patterns observed or recorded in all cases. Alarm conditions permitted RT the ability to predict partial obstructions degrading to apneas from complete obstructions, allowing RT stimulation of the patient to improve breathing effort. Conclusion: The team knows capnography is more accurate and faster in hypoventilation recognition than oximetry. Capnography can assure breathing variance for airway patency with inhaled NO. Capnography in the CVL is the facility standard method for assurance of airway patency before and after delivery of inhaled NO during VR testing. Sponsored Research - None

Vasoreactivity Testing with Sedation - EtCO2 and RR data