ASATT National Certification Exam (NCE) Practice Exam

A sudden decrease in end tidal CO2 during a laparoscopic cholecystectomy can indicate the presence of a gas embolus. This condition occurs when gas, often from the carbon dioxide used to create the pneumoperitoneum for laparoscopic surgery, enters the venous system and travels to the right side of the heart and then to the pulmonary circulation.

When a gas embolus occurs, there is an interruption in the normal circulation of blood and gas exchange in the lungs, which can lead to a rapid decrease in the amount of CO2 being exhaled. This results in a sudden drop in end tidal CO2 readings. This finding is significant and may require immediate intervention, as a gas embolus can lead to serious complications, including cardiovascular collapse and respiratory distress.

While hypoventilation might lead to an increase in end tidal CO2 rather than a decrease, conditions such as medication errors or pneumothorax would typically manifest with different physiological signs. For example, a medication error could produce various alterations in patient vitals based on the drug involved, but it wouldn't specifically be indicated by a decrease in end tidal CO2. Similarly, a pneumothorax might lead to other respiratory changes that are not characterized solely by a sudden