Question
Tube shown below causes resistance which is primarily because of
| A. |
Curvature
|
| B. |
Circumference
|
| C. |
Length
|
| D. |
Diameter
|
Show Answer
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Correct Answer » D
Explanation
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|
According to Poiseuille’s law, resistance to laminar flow is inversely proportional to the fourth power of the radius:
Resistance ∝ 1/r⁴
Therefore, even a small reduction in the internal diameter of an endotracheal tube causes a marked increase in resistance.
Why other options are incorrect
- A. Curvature: Has comparatively little effect on resistance.
- B. Circumference: Not the primary determinant used to describe airway resistance.
- C. Length: Resistance is directly proportional to length, but diameter has a much greater effect.