Cough Reflex Test Practice 2025 – Complete Exam Prep

In a jet nebulizer, the entrainment setting determines the ratio of air to oxygen that is mixed for aerosol delivery. If the nebulizer is set to an entrainment setting of 35%, one would typically expect an oxygen concentration that reflects that blend, not significantly higher concentrations like 45%.

The presence of water in the tubing can obstruct and alter the airflow and gas mixture dynamics, leading to a higher concentration of oxygen being delivered than what the entrainment setting would predict. Water accumulation can create a resistance to airflow, reducing the amount of room air that is entrained, thereby concentrating the oxygen in the mixture delivered to the patient. This explains why a higher-than-expected oxygen concentration might be observed under those conditions.

Other factors, such as flow rates or oxygen supply, could also influence oxygen concentration but are less directly related to the immediate mechanical setup of the nebulizer itself compared to the effect of water in the tubing. A malfunctioning nebulizer could result in varying outcomes depending on the nature of the malfunction, while an inadequate oxygen supply generally affects pressure and flow rather than entrainment ratios specifically.