Multidrug Aerosol Delivery During Mechanical Ventilation

Abstract

Background: Continuous nebulization of pulmonary vasodilators is an off-label therapy for hypoxemia. Patients may require additional aerosol therapies such as bronchodilators and antibiotics. This study evaluates delivery of concurrent therapy of multiple medications during continuous nebulization without interruption or circuit disconnection.

Methods: One i-AIRE dual-port breath-enhanced jet nebulizer (BEJN) or two Aerogen Solo vibrating mesh nebulizers (VMN) were installed on the dry side of the humidifier. VMN were stacked; one for infusion, the second for bolus drug delivery. The BEJN was powered by air at 3.5 L/min, 50 psig. Radiolabeled saline was infused at 5 & 10 mL/h with radiolabeled 3 mL and 6 mL bolus injections at 30 and 120 min respectively. Two adult breathing patterns (duty cycle 0.13 and 0.34) were tested with an infusion time of 4 h. Inhaled Mass expressed as % of initial syringe activity (IM %/min) was monitored in real time with a ratemeter. All delivered radioaerosol was collected on a filter at the airway opening. Transients in aerosol delivery were documented.

Results: IM %/h during continuous infusion was linear and predictable, mean ± SD: 3.63 ± 2.02%, 3.54 ± 2.78% for BEJN and VMN, respectively. BEJN functioned without incident. VMN continuous aerosol delivery stopped spontaneously in 4 of 8 runs (50%); bolus delivery stopped spontaneously in 9 of 16 runs (56%). Tapping restarted VMN function during 3 of 4 continuous runs and 7 of 9 bolus delivery runs. Bolus delivery IM% (mean ± SD): 22.17 ± 7.65%, 14.37 ± 10.62% for BEJN and VMN, respectively.

Conclusions: Simultaneous continuous and bolus nebulization without circuit disconnection is possible for both jet and mesh technology. Monitoring of VMN devices may be necessary in case of spontaneous interruption of nebulization.