AUTHOR=Zhang Sheng , Zheng Dan , Chu Xiao-Qiong , Jiang Yong-Po , Wang Chun-Guo , Zhang Qiao-Min , Qian Lin-Zhu , Yang Wei-Ying , Zhang Wen-Yuan , Tung Tao-Hsin , Lin Rong-Hai 

TITLE=ΔPCO2 and ΔPCO2/C(a−cv)O2 Are Not Predictive of Organ Dysfunction After Cardiopulmonary Bypass

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=8

YEAR=2021

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2021.759826

DOI=10.3389/fcvm.2021.759826

ISSN=2297-055X

ABSTRACT=<p><bold>Background:</bold> Cardiac surgery is associated with a substantial risk of major adverse events. Although carbon dioxide (CO<sub>2</sub>)-derived variables such as venous-to-arterial CO<sub>2</sub> difference (ΔPCO<sub>2</sub>), and PCO<sub>2</sub> gap to arterial–venous O<sub>2</sub> content difference ratio (ΔPCO<sub>2</sub>/C<sub>(a−cv)</sub>O<sub>2</sub>) have been successfully used to predict the prognosis of non-cardiac surgery, their prognostic value after cardiopulmonary bypass (CPB) remains controversial. This hospital-based study explored the relationship between ΔPCO<sub>2</sub>, ΔPCO<sub>2</sub>/C<sub>(a−cv)</sub>O<sub>2</sub> and organ dysfunction after CPB.</p><p><bold>Methods:</bold> We prospectively enrolled 114 intensive care unit patients after elective cardiac surgery with CPB. Patients were divided into the organ dysfunction group (OI) and non-organ dysfunction group (n-OI) depending on whether organ dysfunction occurred or not at 48 h after CPB. ΔPCO<sub>2</sub> was defined as the difference between central venous and arterial CO<sub>2</sub> partial pressure.</p><p><bold>Results:</bold> The OI group has 37 (32.5%) patients, 27 of which (23.7%) had one organ dysfunction and 10 (8.8%) had two or more organ dysfunctions. No statistical significance was found (<italic>P</italic> = 0.84) for ΔPCO<sub>2</sub> in the n-OI group at intensive care unit (ICU) admission (9.0, 7.0–11.0 mmHg), and at 4 (9.0, 7.0–11.0 mmHg), 8 (9.0, 7.0–11.0 mmHg), and 12 h post admission (9.0, 7.0–11.0 mmHg). In the OI group, ΔPCO<sub>2</sub> also showed the same trend [ICU admission (9.0, 8.0–12.8 mmHg) and 4 (10.0, 7.0–11.0 mmHg), 8 (10.0, 8.5–12.5 mmHg), and 12 h post admission (9.0, 7.3–11.0 mmHg), <italic>P</italic> = 0.37]. No statistical difference was found for ΔPCO<sub>2</sub>/C<sub>(a−cv)</sub>O<sub>2</sub> in the n-OI group (<italic>P</italic> = 0.46) and OI group (<italic>P</italic> = 0.39). No difference was detected in ΔPCO<sub>2</sub>, ΔPCO<sub>2</sub>/C<sub>(a−cv)</sub>O<sub>2</sub> between groups during the first 12 h after admission (<italic>P</italic> &gt; 0.05). Subgroup analysis of the patients with two or more failing organs compared to the n-OI group showed that the predictive performance of lactate and Base excess (BE) improved, but not of ΔPCO<sub>2</sub> and ΔPCO<sub>2</sub>/C<sub>(a−cv)</sub>O<sub>2</sub>. Regression analysis showed that the BE at 8 h after admission (odds ratio = 1.37, 95%CI: 1.08–1.74, <italic>P</italic> = 0.009) was a risk factor for organ dysfunction 48 h after CBP.</p><p><bold>Conclusion :</bold> ΔPCO<sub>2</sub> and ΔPCO<sub>2</sub>/C<sub>(a−cv)</sub>O<sub>2</sub> cannot be used as reliable indicators to predict the occurrence of organ dysfunction at 48 h after CBP due to the pathophysiological process that occurs after CBP.</p>