Aerosol Delivery and Humidification With the Boussignac Continuous Positive Airway Pressure Device

Abstract

BACKGROUND: A simple method for effective bronchodilator aerosol delivery while administering continuing continuous positive airway pressure (CPAP) would be useful in patients with severe bronchial obstruction. OBJECTIVE: To assess the effectiveness of bronchodilator aerosol delivery during CPAP generated by the Boussignac CPAP system and its optimal humidification system. METHODS: First we assessed the relationship between flow and pressure generated in the mask with the Boussignac CPAP system. Next we measured the inspired-gas humidity during CPAP, with several humidification strategies, in 9 healthy volunteers. We then measured the bronchodilator aerosol particle size during CPAP, with and without heat-and-moisture exchanger, in a bench study. Finally, in 7 patients with acute respiratory failure and airway obstruction, we measured work of breathing and gas exchange after a ␤ 2 -agonist bronchodilator aerosol (terbutaline) delivered during CPAP or via standard nebulization. RESULTS: Optimal humidity was obtained only with the heat-and-moisture exchanger or heated humidifier. The heat-and-moisture exchanger had no influence on bronchodilator aerosol particle size. Work of breathing decreased similarly after bronchodilator via either standard nebulization or CPAP, but P aO 2 increased significantly only after CPAP aerosol delivery. CONCLUSIONS: CPAP bronchodilator delivery decreases the work of breathing as effectively as does standard nebulization, but produces a greater oxygenation improvement in patients with airway obstruction. To optimize airway humidification, a heat-and-moisture exchanger could be used with the Boussignac CPAP system, without modifying aerosol delivery.

Effects of Fill Volume and Humidification on Aerosol Delivery During Single-Limb Noninvasive Ventilation

“…Although the humidity change results were far different from most of the previously published in vitro studies, which recommend switching off the humidifier when delivering aerosol to ventilated patients, 9,19,20,[42][43][44][45] the results were very close to our previous findings of the effects of humidity change on aerosol delivery in auto-CPAP ventilated subjects 16 and invasively ventilated subjects. 21,22 This finding shows that there is no need to discomfort the patient by switching off the humidifier for aerosol delivery because the dry gas could potentially be harmful to the lung and the increase in delivered aerosol was insignificant.…”

Nocturnal continuous positive airway pressure in severe non‐apneic asthma. A pilot study

“…Another mechanism to explain the amelioration of PEF variability in severe asthmatics after the CPAP treatment might be the improvement of the delivery of bronchodilators by ventilation compared with conventional inhalation techniques . However, the patients received their inhaled medications at least 1 h before and 2 h after the CPAP treatment to avoid any interference with the deposition of drugs.…”

Effects of Heat and Humidification on Aerosol Delivery during Auto-CPAP noninvasive Ventilation

“…Humidifi cation of the ventilator circuit is one of the factors that were well studied for optimization of aerosol delivery in NIV patients [5][6][7][8][9][10][11]. Optimal humidifi cation of the inhaled gas could improve patient comfort, facilitate use of the mask, and improve bronchodilator effects in those requiring NIV [2].…”

“…Most studies of humidifi cation effects on aerosol delivery were in-vitro and all of them recommend switching off the humidifi er while delivering aerosol to NIV patients for better delivery [5][6][7][8][9][10][11]. However, the undesirable effect of inhaled dry gas, e.g.…”

“…The source of confl ict among the previous researches is between the impact of adding humidity to the circuit to prevent airway dryness and resistance [2,13] humidity would decrease the inhaled drug aerosol in the tested lung [5][6][7]14] So, the aim of this study was to evaluate the effect of humidifi cation on the relative pulmonary and systemic bioavailability of salbutamol delivery to Auto-CPAP noninvasively ventilated COPD patients via different inhalation methods.…”