Explain the physiological factors that affect airway resistance.
It was expected candidates cover the breadth of the factors that affect airway resistance. Generally, as a concept the type of flow (laminar vs turbulent) was answered well by most candidates, however many failed to mention the other factors that affect airway resistance. Airway diameter as a primary determinant of airway resistance was commonly omitted. Better answers which covered the factors affecting airway diameter classified them broadly and included examples such as physical compression/external obstruction, broncho-motor tone and local cellular mechanisms. Some answers did not explain these factors in enough detail and often with incorrect facts.
Factors which affect airway resistance
Other factors which affect respiratory resistance as a whole:
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Bruno Marciniak, in A Practice of Anesthesia for Infants and Children (Sixth Edition), 2019