2004 OPEN FORUM Abstracts
COMPARISON OF DRUG DELIVERY BY VARIOUS MDI SPACERS IN A NEONATAL LUNG MODEL
Rick Amato, BS,
RRT-NPS, James Johnson, BS, CRTT, Shelly Smith, RRT Cincinnati
Children’s Hospital Medical Center, Cincinnati, Ohio
Introduction: MDI
delivery during mechanical ventilation requires a spacer, involving
opening of the circuit and added dead space. We created an in line
MDI adapter for the inspiratory limb of the neonatal circuit. This
adaptor eliminates opening of the circuit and dead space, and the
circuit acts as the reservoir. We measured drug delivery using our
new MDI adaptor and different spacers or adaptors in a neonatal lung
model to see if our MDI adaptor provided comparable drug delivery.
Materials and
Methods: Our lung model was a Siemens™ Servo 300®
ventilator and Ingmar Medical™ Neonatal Demonstration Lung.
Ventilator settings were: Pressure Control (PC) mode, Rate 40 bpm,
Peak Inspiratory Pressure (PIP) 20 cm H2O, PEEP 5 cm H2O,
Inspiratory Time (Ti) 0.4 seconds.
Spacers tested were
placed between the patient wye and a filter located proximal to a
4.5mm ETT connected to the lung model, while our MDI adaptor was
placed in the inspiratory limb of the circuit proximal to the patient
wye. Two puffs of Albuterol MDI (17grams/ 90mcg per actuation) 30
seconds apart were given using each spacer and filters were changed
and identified to each spacer. Drug levels were measured with a
Beckman 640 spectrophotometer at a wavelength of 276 nm. A sample of
HCL solution was used as a placebo, and zeroed.
(Disposable supplies
used were: Pall™ Breathing Circuit Filters (cat# BB50T),
Airlife™ isothermal breathing circuit (cat# 9048-4H2),
Monaghan™ AeroChamber® MV, Airlife™ Dual Spray
Minispacer (cat# 002090), Airlife™ Minispacer (cat# 002092),
Airlife™ Minispacer (cat# 002063), Airlife™ T-Adaptor
(cat# 5941-504), and an actuator from an Airlife™ Minispacer
(cat# 002063), modified to place the actuator in the inspiratory
stream.)
Results: Averages
were obtained, Monaghan™ AeroChamber® MV was found
to deliver 0.0276mg/ml. Airlife™ Dual Spray Minispacer (cat#
002090) delivered 0.0322mg/ml. Airlife™ Minispacer (cat#
002092) delivered 0.0277mg/ml. Airlife™ Minispacer (cat#
002063) delivered 0.0244mg/ml. The “home made” MDI
adaptor delivered 0.0270mg/ml.
Conclusion: While
our “home made” MDI adaptor did not deliver the highest
concentration of medication, the patient safety factors played an
important role in our decision to use it. There was no increase in
dead space, and our patients tolerated treatments better than using
the adaptor that delivered the most medication. The circuit only had
to be broken into once, and the adaptor could be left in-line. This
enabled us to deliver an MDI with out disturbing the patient, or
removing them from the ventilator.