Question

You are ventilating a patient with a​ bag-valve mask. Under which circumstance would you not follow the three inches rule for this​ patient?

Answer 1

The three inches rule refers to compressing the bag-valve mask during manual ventilation. However, there may be exceptions to this rule, such as when the patient has a physiological shunt or is experiencing hyperpnea.

Step-by-step explanation:

The three inches rule refers to the practice of compressing the bag-valve mask by approximately three inches during manual ventilation of a patient. This rule ensures adequate air exchange and prevents excessive lung inflation. However, there may be circumstances where the three inches rule should not be followed, such as:

1. If the patient has a physiological shunt, which is a condition where ventilation is decreased but perfusion is not affected. In this case, the V/Q ratio changes, and gas exchange is affected. The three inches rule may need to be adjusted based on the patient's specific condition.
2. Another circumstance where the three inches rule may not be followed is when the patient is experiencing hyperpnea, which is an increased rate and depth of ventilation due to an increase in oxygen demand that does not significantly alter blood oxygen or carbon dioxide levels. In this case, the bag-valve mask may need to be compressed further than three inches to meet the patient's increased respiratory needs.