126 S. Diop et al.: J Extra Corpor Technol 2025, 57, 123--128
Table 2. Blood gas analysis at the beginning and the end of the circulatory arrest. Variables
ABG at the beginning of circulatory arrest
ABG at the end of circulatory arrest
Alpha stat |
pH stat |
Alpha stat |
pH stat |
FiO 2(%) |
92.7(± 9.6) |
pH |
7.31(± 0.09) |
7.56(± 0.09) |
7.51(± 0.14)* |
7.79(± 0.16)* |
PaCO 2( mmHg) |
43.2(± 9.9) |
19.5(± 4.7) |
23.4(± 11.9)* |
11.3(± 5.8)* |
PaO 2( mmHg) |
735(± 74) |
602(± 124) |
692(± 187)* |
612(± 161)* |
SaO 2(%) |
99.9(± 0.16) |
99.9(± 0.5) |
HCO � 3( mmol / L) |
20.9(± 2.9) |
19.8(± 3.9) |
Excess Base( mmol / L) |
�3.5(± 5.8) |
�4.5(± 3.9) |
Lactate( mmol / L) |
3.3(± 1.0) |
3.4(± 0.8) |
Sodium( mmol / L) |
139(± 3.0) |
137(± 2.9)** |
Chloride( mmol / L) |
112(± 3.5) |
114(± 3.5) |
Potassium( mmol / L) |
4.5(± 0.8) |
4.7(± 0.7) |
Calcium( mmol / L) |
1.15(± 0.04) |
1.13(± 0.07)** |
Strong ion difference( mmol / L) |
31.6(± 4.4) |
28.7(± 4.3)** |
Hemoglobin( g / dL) |
9.7(± 1.0) |
9.6(± 1.0) |
Results are expressed in mean(± SD). * p < 0.0001 compared to initial value. ** p < 0.05 compared to initial value. PaO 2: arterial partial pressure of O 2; PaCO 2: arterial partial pressure of CO 2; SaO 2: arterial oxygen saturation. Figure 1. Spearman correlation analysis between pH( alpha-stat analysis), PaCO 2 at the end of the circulatory arrest, and the gas sweep inflow set up on the CPB. Figure 2. Spearman correlation analysis between first, the pH( alpha-stat analysis) at the end of the circulatory arrest and the duration of the circulatory arrest, and second, the pH( alpha-stat analysis) at the end of the circulatory arrest and the arterial shunt line flow.
Discussion
In this pilot study, we investigated the dynamic evolution of the acid-base balance and electrolyte status of the blood contained in the cardiotomy reservoir, between the beginning and the end of the deep hypothermic circulatory arrest, in patients undergoing PAE surgery.
Our results showed that the pH significantly increases and that the PaCO 2 decreases during DHCA. The gas sweep inflow was well correlated with the post-DHCA pH, whereas the arterial shunt line flow and the duration of DHCA were not. In some cases, the pH was as high as 7.8 at the end of the DHCA( alpha-stat). The rise in pH and the drop in PaCO 2 are related to the continuous elimination of CO 2 from the blood contained in