The Science Journal of the American Association for Respiratory Care

1998 OPEN FORUM Abstracts

AEROSOLIZED ALBUTEROL DELIVERY BY HIGH FREQUENCY OSCILLATION AND BY CONVENTIONAL VENTILATION: A BENCH STUDY.

William Quinn RRT RPFT, Mary McGettigan MD, Ochsner Foundation Hospital, New Orleans, LA.

We sought to determine whether a small volume nebulizer (SVN) placed in line with a high frequency oscillator (HFO) delivered as much albuterol to a test lung as it did when placed in line with a conventional ventilator (CV.) We also sought to distinguish how much of the delivered albuterol was instilled in the lung from large droplets which form on the interior of the endotracheal tube (ETT.) Our hypothesis was that less total albuterol would be delivered with HFO than with CV. Methods and materials: An SVN was attached to the temperature port on the inspiratory side of a ventilator circuit which was in turn attached to a 3.0 mm ETT held in brackets in a curved position. The other end of the ETT was attached via a set of 15x22 mm adapters to a 1 ml/cm H2O test lung. Trials A anc C were performed with a CV (Sechrist 1000IV) set at a rate of 60, a PIP of 30 cm H_{2}O, CPAP of 4 cm H_{2}O, and T_{i} of 0.4 seconds. Trials B and D were performed with an HFO (Sensormedics 3100a) set at a rate of 15 Hz, a [DELTA]P of 33 cm H_{2}O, and a P_{aw} of 15 cm H_{2}O. In trials A and B a cotton ball was placed inside the adapters directly on the end of the ETT. In trials C and D the adapters between the ETT tube and the test lung were arranged so that a "drip trap" was below the ETT tube opening and gas went through a right angle turn before reaching a cotton ball. Ten repetitions of each trial were done. In all trials the nebulizer was operated at 7 L/minute with 2.5 mg of albuterol in a 3 ml solution. The nebulizer was run until exhausted, after which the cotton ball was removed and washed with 20 ml of saline solution. This solution was analyzed by spectrophotometry to measure the albuterol content, which was then expressed as a percentage of total albuterol in the nebulizer. Results (see table) were subjected to ANOVA and the Krusskal-Wallis H test. A and B were NSD (P-value >.4.) C was significantly less than A and B, and D was significantly less than all other trials (P-value < .01.)

Conclusion: Roughly equal amounts of albuterol reach the lung from an SVN whether HFO or CV is employed, but when HFO is used, more of the drug is instilled at the carina instead of being delivered as a mist.

(See Original for Figure)

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

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