Development of acidosis in human beings during closed-chest and open-chest CPR

We studied the development of acidosis, as measured by blood gases, in a convenience sample of 16 patients undergoing five minutes of closed-chest CPR (CC-CPR) followed by five minutes of open-chest CPR (OC-CPR). To eliminate the influence of variable pCO2 on serum pH, all blood gas values were adjusted to a pCO2 of 40 mm Hg. Adjusted pH fell a mean of 0.09 U (SEM +/- 0.03, P = .02) with five minutes of CC-CPR and then 0.05 U (SEM +/- 0.02, P = .05) with five minutes of OC-CPR. The decline in adjusted pH during CC-CPR was statistically comparable to the decline that occurred during OC-CPR. The development of acidosis as measured by blood gases does not appear to be significantly different for patients undergoing five minutes of CC-CPR versus five minutes of OC-CPR when OC-CPR follows CC-CPR.