Associations between oxygen delivery and cardiac index with hyperlactatemia during cardiopulmonary bypass.

ABSTRACT:

Objective

Metabolism management plays an essential role during cardiopulmonary bypass (CPB). There are different metabolic management devices integrated to heart-lung machines; the most commonly used and accepted metabolic target is indexed oxygen delivery (DO_2i) (280 mL/min/m²) and cardiac index (CI) (2.4 L/min/m²), which can be managed independently or according to other metabolic parameters. Our objective was to compare lactate production during CPB procedures using different metabolic management: DO_2i in relation to indexed oxygen extraction ratio (O₂ER_i) and CI in relation to mixed venous oxygen saturation (SvO₂).

Methods

Data on 500 CPB procedures were retrospectively collected in a specialized regional tertiary cardiac surgery center in Italy between September and 2012 and November 2019. In group A, the DO_2i with 280 mL/min/m² target in relation to O₂ER_i 25% was used; in group B, CI with 2.4 L/min/m² target in relation to SvO₂ 75% was used. During CPB, serial arterial blood gas analyses with blood lactate and glucose determinations were obtained. Hyperlactatemia (HL) was defined as a peak arterial blood lactate concentration >3 mmol/L. The postoperative outcome of patients with or without HL was compared.

Results

Eight pre- and intraoperative factors were found to be significantly associated with peak blood lactate level during CPB at univariate analysis. HL (>3 mmol/L) was detected in 15 (6%) patients of group A and in 42 (16.8%) patients of group B (P = .022); hyperglycemia (>160 mg/dL) was found in 23 (9.2%) patients of group A and in 53 (21.2%) patients of group B (P = .038). Patients with HL during CPB had a significant increase in serum creatinine value, higher rate of prolonged mechanical ventilation time and intensive care unit stay. A cutoff of DO_2i <270 mL/min/m² in relation to O₂ER_i >35% in group A and a cutoff of CI <2.4 L/min/m² in relation to SvO₂ <65% in group B were found to have a positive predictive value of 80% and 75% for HL, respectively. A cutoff of DO_2i >290 mL/min/m² in relation to O₂ER_i 24% in group A and a cutoff of CI >2.4 L/min/m² in relation to SvO₂ >75% in group B were found to have a negative predictive value of 78% and 62% for HL, respectively.

Conclusions

This retrospective observational analysis showed that management of DO_2i in relation to O₂ER_i was 16% more specific in terms of negative predictive value for HL during CPB compared with the use of CI in relation to SvO₂. Group A reported a significant reduction in the incidence of intraoperative lactate peak, correlated with postoperative reduction of serum creatinine value, mechanical ventilation time, and intensive care unit stay, compared with group B.

SUBMITTER: Condello I 

PROVIDER: S-EPMC8299069 | biostudies-literature |

REPOSITORIES: biostudies-literature