Which CO2-related change tends to be greatest in the first 20 minutes of pneumoperitoneum?

Which CO2-related change tends to be greatest in the first 20 minutes of pneumoperitoneum?

• A. Blood pH falls most after 2 hours
• B. White blood cell count rises
• C. Platelet count decreases
• D. End tidal CO2 increases the most

Answer: (D)

During pneumoperitoneum with CO2, the gas is absorbed across the peritoneal surfaces into the bloodstream. In the first 20 minutes, this rapid diffusion raises arterial CO2 levels, and the amount of CO2 being exhaled per breath (end-tidal CO2) increases accordingly. Capnography tracks this closely, so the end-tidal CO2 rises most early on. Other changes, like WBC or platelet shifts, are not immediate responses to CO2 insufflation, and a pH drop due to hypercapnia tends to develop later rather than right at the 20-minute mark. So the most pronounced early CO2-related change is the rise in end-tidal CO2.

During pneumoperitoneum with CO2, the gas is absorbed across the peritoneal surfaces into the bloodstream. In the first 20 minutes, this rapid diffusion raises arterial CO2 levels, and the amount of CO2 being exhaled per breath (end-tidal CO2) increases accordingly. Capnography tracks this closely, so the end-tidal CO2 rises most early on. Other changes, like WBC or platelet shifts, are not immediate responses to CO2 insufflation, and a pH drop due to hypercapnia tends to develop later rather than right at the 20-minute mark. So the most pronounced early CO2-related change is the rise in end-tidal CO2.