1997 OPEN FORUM Abstracts
PULSE DOSED INHALED NITRIC OXIDE THERAPY FOR A PATIENT WITH PRIMARY PULMONARY HYPERTENSION
Michael Tracy RRT, Robert Chatburn RRT, Lia Lowrie MD, Kingman Strohl MD. Rainbow Babies and Childrens Hospital, Case Western Reserve University, Cleveland, Ohio.
INTRODUCTION Inhaled nitric oxide (NO) is a selective pulmonary vascular smooth muscle relaxant. It readily crosses the alveolar endothelial membrane to cause relaxation in the underlying vascular smooth muscle. This decreases the pulmonary artery pressure and improves the ventilation-perfusion relationship without adversely affecting the systemic vascular resistance. NO then passes through the alveolar capillary membrane and is deactivated as it binds to hemoglobin.
CASE SUMMARY The subject is a 47 year old female who was diagnosed with primary pulmonary hypertension in 1986. Her condition deteriorated and she was listed for lung transplantation. The patient declined lung transplantation) secondary to improvement with medical management and transtracheal oxygen. She was referred for a trial of pulse dosed inhaled nitric oxide in June 1996 after her condition progressively deteriorated following general anesthesia and surgery for an unrelated condition. She was admitted to the SICU where a Swan-Ganz catheter was placed and she was given a trial of pulse dosed inhaled nitric oxide (NO) via nasal canula. A standard oxygen pulse dose delivery system (PDDS) (DeVilbiss OMS-50) was modified according to Channick et al (Chest1996;109:6:1545-1549) and attached to an 80 PPM source of nitric oxide. The actual calculated delivery is equal to 20 PPM +/- 5 PPM based on changes in respiratory rate, tidal volume and inspiratory flow rate.
Administration of NO resulted on a 16% decrease in mean Pulmonary artery pressure. The patient was discharged home with NO and instructed to use it 24 hrs/day. Our home based NO equipment includes one PPDS on a 4,100 L NO tank for use in the home and one PDDS on a 580 L NO tank as a portable system for use outside the home. 4,100 L tanks have lasted an average of 10 days (average cost $36/day). 580 L tanks have lasted an average of 24 hours (average cost $5.80/hour) Objective measures of continuing success of NO include a 26% increase in distance walked in a standard 6 min. walk test and 16% decrease in systolic pulmonary artery pressure per echocardiogram at the six month follow up. The patient indicates marked improvement in the quality of her life, as assessed by standardized questionnaire (Rand Health Sciences Program)
DISCUSSION We have shown that that patient's resting oxygen requirement has been reduced from 3 L to 1 L, her quality of life has improved and she has resumed activities she had become physically unable to do. Additionally, we have been able to trigger the PDDS through a transtracheal oxygen catheter (while delivering oxygen through a nasal cannula). In conclusion we have shown that long term NO therapy is safe and effective with the use of a pulsed dose system. Greater savings may be possible with NO via transtracheal catheter.