Final answer:
Improper head and airway positioning while performing positive pressure ventilation can lead to airway obstruction, creating a physiological shunt, impacting breathing, and altering gas exchange by causing a V/Q mismatch.
Step-by-step explanation:
Failure to properly position the head and airway when attempting positive pressure ventilation will likely lead to problems such as airway obstruction, which can severely impact breathing and reduce the surface area available for gas diffusion. This can result in the development of what is known as a physiological shunt, where the ventilation of an area of the lung is decreased but perfusion is not affected, leading to a change in the V/Q ratio and affecting gas exchange. In such a case, the oxygen level in the blood may decrease, and the carbon dioxide level may increase, potentially causing severe complications such as hypoxemia or hypercapnia.