The Science Journal of the American Association for Respiratory Care

1998 OPEN FORUM Abstracts

AN IN VITRO COMPARISON OF TWO METHODS OF AEROSOLIZED BRONCHODILATOR DELIVERY TO INTUBATED MECHANICALLY VENTILATED NEONATES

Beth Brown, MS. RRT, Macon State College, Macon, Georgia, & Bob Harwood, MSA, RRT, Georgia State University, Atlanta, Georgia.

Mechanically ventilated neonates are often candidates for aerosol therapy because of pre-existing lung conditions. We report here the results of two methods of aerosol delivery to mechanically ventilated neonates.

Method: A Sechrist IV neonatal ventilator in the IMV mode was used to ventilate a lung model with standard settings: IMV mode, PIP 25cmH2O, respiratory rate 25 bpm, inspiratory time of 0.5 seconds, and PEEP of 5 cm H2O. A disposable neonatal circuit was attached to a 3.0 ETT and test lung. The ETT was attached to a template that simulated the curvature of the upper airway fashioned from a lateral neck radiograph of a neonate. A heated humidifier was used. In method one 2.5mg of albuterol was delivered by a MiniHeart ^{TM} nebulizer at 2 L/M in line through the inspiratory limb of the patient circuit 18 inches from the wye adapter. In method two 25 puffs from an MDI attached to a spacer and placed between the wye adapter and the inspiratory limb of the patient circuit was delivered. Drug exiting the ETT was captured by a filter attached to the end of the ETT, dissolved with alcohol and measured by spectrophotometer.

The results are as follows:

Trial MiniHeart % of Total MDI % of Total

(mcg) Dose (mcg) Dose

1 145.5 5.8 197.1 8.8

2 50 2.0 182.5 8.1

3 53 2.12 158.3 7.0

4 42 1.68 129.7 5.8

5 115 4.6 184.8 8.2

Mann-Whitney U Test, a non parametric test for unpaired samples, showed that each method differed significantly from each other (p=0.016).

Conclusion: Use of an MDI with spacer device has a greater % of dose at the end of the ETT as compared to the MiniHeart nebulizer when placed in line on the inspiratory limb with a heated humidifier.

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

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