What effect does the addition of surfactant have on the airflow? how well did the results compare with your prediction?

Surfactant increases airflow. It has this effect on airflow because it reduces resistance to lung inflation.  Airflow increased as predicted.

Explanation:

Pulmonary surfactant is a complex mixture of lipids and proteins secreted by the Type II alveolar cells. The major component of surfactant, dipalmitoyl-phosphatidylcholine (DPPC), is an amphiphatic phospholipid. The main function of the pulmonary surfactant is to reduce the surface tension at the air/liquid interface in the lungs by forming lining layer between the aqueous airway liquid and the inspired air. prevents alveolar and airway collapse at end-expiration and thus allows cyclic ventilation of the lungs. It decreases surface tension in the alveoli making it easier for the alveoli to increase surface area for gas exchange. By lowering alveolar surface tension, pulmonary surfactant provides two important benefits:

(1) it increases pulmonary compliance, reducing the work of inflating the lungs; and

(2) it reduces the lungs’ tendency to recoil, so they do not collapse as readily.