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-Disk®, November 7 - 10, 1998, Atlanta, Georgia.