Aerosol delivery in models of pediatric high flow nasal oxygen and mechanical ventilation

BackgroundAerosol drug delivery during high flow nasal oxygen (HFNO) and invasive mechanical ventilation (IMV) are key respiratory care strategies available for the treatment of pediatric patients. We aimed to quantify the impact of different HFNO and IMV set-ups on tracheal drug delivery via a vibrating mesh nebuliser (VMN). MethodsPercent tracheal dose via VMN was quantified during HFNO therapy and IMV in a benchtop model of a 9-month-old infant. Under HFNO, 3 cannula sizes were used at 3 flow rate settings with the VMN placed at the dry side of the humidifier. Under IMV, tracheal dose when VMN was placed at the dry side of the humidifier, 15 cm from the wye and between the wye and endotracheal tube (ETT) was assessed. Salbutamol at 2.5 mg/2.5 ml (1 mg/ml) was used for each test (N = 5). The impact of VMN refill on circuit pressure under HFNO and IMV was also assessed. ResultsTracheal dose was highest during HFNO with the largest cannula size (OPT318) set to the lowest flow rate setting of 2 L/min (liter per minute) (5.80 +/- 0.17%). Increasing flow rate reduced tracheal drug delivery for all cannulas. For IMV, VMN on the dry side of the humidifier and between the wye and ETT gave optimal drug delivery (4.49 +/- 0.14% vs. 4.43 +/- 0.26% respectively). VMN refill did not impact circuit pressure for either HFNO therapy or IMV. ConclusionsGas flow rate and cannula size during HFNO and VMN position during IMV has a significant effect on tracheal drug delivery in a pediatric setting.

Automated summary

This study aimed to evaluate the impact of different set-ups of high flow nasal oxygen (HFNO) and invasive mechanical ventilation (IMV) on tracheal drug delivery using a vibrating mesh nebuliser (VMN). The results showed that tracheal drug delivery was highest during HFNO when using the largest cannula size and the lowest flow rate setting. For IMV, optimal drug delivery was achieved when the VMN was placed between the dry side of the humidifier and the wye or endotracheal tube.