The Science Journal of the American Association for Respiratory Care

1998 OPEN FORUM Abstracts


William R. Howard, MBA, RRT. Respiratory Care, New England Medical Center, Boston, MA.

BACKGROUND: Mechanically ventilated patients diagnosed with pulmonary hypertension and hypoxemic respiratory failure have received Nitric oxide (NO) therapy at our institution for approximately 5 years. The non-neonatal group has received this therapy using a PB-7200 ventilator. There is a problem however, in transporting these patients within the institution for various diagnostic procedures. This problem is of concem especially when patient's ventilatory requirements exceed the limits of a manual resuscitation device, e.g. during PCV or with FIO_{2} > 85%. TBird-AVSIII, Bird Medical Products, Palm Springs, CA, has solved this problem by providing a convenient and safe method of uninterrupted mechanical ventilation, regardless of mode and FIO_{2}. We wanted to determine if this ventilator could also provide a reasonable means of providing NO outside of the ICU environment. We will evaluate the capability of providing NO in conjunction with transport using the TBird-AVSIII. Methods: A standard patient circuit was connected to a TBird-AVSIII. Oxygen from 2 E size cylinders was fitted and connected with high-pressure hoses connected to a high-pressure tee. The tee was connected to one of the oxygen inlets on the TBird. A continuous flow of nitric oxide, BOC Gases, Murray Hill, NJ, was supplied to the inspiratory limb of the TBird patient circuit, from a 400ppm source tank using a Timeter Classic 200 model low-flow flowmeter, Allied Healthcare Products, Inc., St. Louis, MO. We bench tested using a test lung, BioTek VT-2, Winooski, VT, set for a compliance of 15 ml/cmH20 in the AC and PCV modes with desired NO concentrations of 5, 10, and 20ppm at flowrates of 200, 400 and 800 ml/min. In the AC mode, settings were: exhaled VE adjusted to achieve 8, 12, 16, and 20 liters, RR 10, 15, and 20BPM, FIO_{2} 95%, PEEP- 5 and 10 cmH_{2}0. In PCV target pressure adjusted to achieve exhaled minute volume of 8, 12, 16, and 20 liters, at RR of 10, 15, and 20BPM, FIO_{2} 95%, PEEP- 5 and 10 cmH_{2}0. Testing consisted of 10-minute runs at each setting. The delivered NO concentration was continuously sampled with an electrochemical measurement device, Pulmonox II-RT, Pulmonox Medical Corporation, Canada, using a side stream analysis method. The analyzer was calibrated per manufacturer's instructions. Measurements were recorded at 10-minute intervals. Results: The mean measurements of NO with SD are in the following table for the total group, the PCV group, and the AC group separately.

Dose (cc/min) 200 400 800

MEAN Total 6.1 11.0 20.1

STDEV Total 1.8 3.3 4.9

MEAN PCV 6.4 12.3 21.3

STDEV PCV 1.8 3.5 5.3

MEAN AC 5.7 8.9 18.4

STDEV AC 1.8 1.6 3.6

CONCLUSION: NO administration with TBird-AVSIII was acceptable at desired concentrations of 5-20 ppm. Stable NO concentrations were delivered at minute volumes ranging from 8-20 L/M using I:E ratios of 1:2 to 2:1 in either AC or PCV modes. Continuance of identical life support delivery needs outside the ICU, inclusive of NO administration, is possible with the TBird-AVSIII ventilator.

The 44th International Respiratory Congress Abstracts-On-DiskĀ®, November 7 - 10, 1998, Atlanta, Georgia.