Final answer:
Difficult mask ventilation can result from decreased lung compliance due to diseases such as fibrosis or increased resistance from conditions like asthma, leading to V/Q mismatch and impacted gas exchange.
Step-by-step explanation:
Difficult mask ventilation is often caused by changes in lung compliance and resistance, leading to issues with breathing and gas exchange. Decreased compliance may be due to restrictive diseases like fibrosis, where the lungs stiffen and cause the airways to collapse upon exhalation, trapping air. This results in lowered forced functional vital capacity (FVC) and prolonged exhalation times. Increased resistance, seen in conditions like asthma or emphysema, leads to obstruction and trapped air in the lungs.
Alterations in the ventilation of the airways or perfusion of the arteries can also contribute to V/Q mismatch (ventilation-perfusion mismatch), which can be due to anatomical or physiological changes, such as physiological shunts caused by infections or edema in the lungs. This affects gas exchange as the obstructed areas decrease ventilation without affecting perfusion. The narrowing of airways during an asthma attack can also escalate resistance, making it more difficult for air to flow and resulting in increased effort for gas exchange.