The Use of lactate as a marker of occult hypoperfusion and outcome following adult cardiac surgery

Ahmed Sobhy; Khadiga Fathy; Ibrahim Kasb; Yousry  Shaheen; Mohammed El Gazzar

Ahmed Sobhy Department of Cardiothoracic Surgery, Faculty of Medicine, Banha University, Banha, Egypt
Khadiga Fathy Department of Cardiothoracic Surgery, Faculty of Medicine, Banha University, Banha, Egypt
Ibrahim Kasb Department of Cardiothoracic Surgery, Faculty of Medicine, Banha University, Banha, Egypt
Yousry Shaheen Department of Cardiothoracic Surgery, Faculty of Medicine, Banha University, Banha, Egypt
Mohammed El Gazzar Department of Cardiothoracic Surgery, Faculty of Medicine, Banha University, Banha, Egypt

Keywords: Coronary Artery Bypass Grafting, Hyperlactaemia, Cardiopulmonary bypass, Aortic cross-clamp

Abstract

Background: Hyperlactaemia (HL) is a hypoperfusion marker associated with increased mortality. We aimed to determine whether postoperative serial arterial lactate (AL) measurements after cardiac surgery could predict mortality, atrial fibrillation, wound infection, prolonged ventilation, ICU stay duration, and renal failure.

Methods: Between September 2020 and November 2022, this prospective cohort study was conducted on 100 patients who were split into two groups: Group 1 (n= 17) had low lactate levels, and Group 2 (n= 83) had high lactate levels equivalent to or greater than 4 mmol/L.

Results: Body mass index (BMI) (26± 2.6 vs. 23.2 ±1.4, P 0.001), diabetes mellitus (59% vs. 29.4%, P = 0.026), and smoking (57.8% vs. 17.6%, P = 0.003) were all significantly higher in Group 2. Group 2 had a significantly longer cross-clamp time (77 22 vs. 64 26; P = 0.043). Atrial fibrillation (39.8% vs. 0%, P = 0.001), ventilation time (24 (8- 150) vs. 8 (6- 12) hours, P = 0.001), renal dysfunction (26.5% vs. 0%, P = 0.016), length of ICU stay (4 (1- 10) vs. 2 (2- 3) days, P = 0.001), and mortality (28.9% vs. 0%, P = 0.04) were all significantly higher in Group 2. Peak intraoperative lactate showed moderate significant positive correlations with BMI (r = 0.349, p < 0.001), cross-clamp (r = 0.483, P < 0.001), cardiopulmonary bypass time (r = 0.426, P < 0.001), and length of ICU stay (r = 0.468, P < 0.001).

Conclusion: Hyperlactatemia could be associated with higher postoperative morbidity and mortality. Hyperlactemia and its causes should be treated once diagnosed to improve the outcomes.