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Updated: Aug 31, 2025
In vitro Assessment of Myocardial Protection following Hypothermia-Preconditioning in a Human Cardiac Myocytes Model
Published on: October 27, 2020
Mild hypothermia during cardiopulmonary bypass assisted CABG is associated with improved short- and long-term
K D W Hendriks1, J N Castela Forte1, W F Kok1
1Department of Clinical Pharmacy and Pharmacology, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands.
Insights
Optimal patient body temperature during cardiac surgery is crucial for survival. Mild hypothermia (32-35°C) during cardiopulmonary bypass was associated with improved 30-day and 5-year survival rates in CABG patients.
Area of Science:
- Cardiovascular Surgery
- Physiology
- Medical Thermoregulation
Background:
- Optimal patient body temperature during cardiac operations requiring cardiopulmonary bypass is not well-established.
- Existing data lacks clear guidelines for temperature management during these procedures.
- Understanding temperature's impact on survival is critical for improving patient outcomes.
Purpose of the Study:
- To investigate the association between intraoperative patient temperature management and 30-day and 5-year survival.
- To determine the optimal temperature range during cardiopulmonary bypass for coronary artery bypass grafting (CABG) surgery.
- To identify patient subgroups that may benefit from specific temperature strategies.
Main Methods:
- Retrospective analysis of 5,672 adult patients undergoing CABG between 1997 and 2015.
- Continuous monitoring of intraoperative nasopharyngeal temperatures.
- Multivariate Cox regression and machine learning-based cluster analysis to assess temperature's impact on mortality and identify patient subgroups.
Main Results:
- Mild hypothermia (32-35°C) was independently associated with improved 30-day (98%) and 5-year (88%) survival compared to other temperature categories.
- Severe hypothermia (<30°C) showed lower survival rates (93% 30-day, 80% 5-year).
- Normothermia (35-37°C) was associated with the lowest survival (93% 30-day, 72% 5-year).
- Highest survival across all patient subgroups was observed at 32°C.
Conclusions:
- Mild hypothermia, particularly around 32°C, appears optimal for patient survival during cardiopulmonary bypass in CABG.
- Patient subgroups defined by gender, age, kidney function, and weight did not alter the survival benefit of mild hypothermia.
- Further prospective randomized controlled trials are warranted to confirm optimal patient temperatures during cardiopulmonary bypass.
Abstract:
Data substantiating the optimal patient body temperature during cooling procedures in cardiac operations are currently unavailable. To explore the optimal temperature strategy, we examined the association between temperature management and survival among patients during cardiopulmonary bypass assisted coronary artery bypass grafting (CABG) procedures on 30-days and 5-year postoperative survival. Adult patients (n = 5,672, 23.6% female and mean (SD) age of 66 (10) years) operated between 1997 and 2015 were included, with continuous measured intraoperative nasopharyngeal temperatures. The association between mortality and patient characteristics, laboratory parameters, the lowest intraoperative plateau temperature and intraoperative cooling/rewarming rates were examined by multivariate Cox regression analysis. Machine learning-based cluster analysis was used to identify patient subgroups based on pre-cooling parameters and explore whether specific subgroups benefitted from a particular temperature management. Mild hypothermia (32-35°C) was independently associated with improved 30-days and 5-year survival compared to patients in other temperature categories regardless of operation year. 30 days and 5-year survival were 98% and 88% in the mild hypothermia group, whereas it amounted 93% and 80% in the severe hypothermia (<30°C). Normothermia (35-37°C) showed the lowest survival after 30 days and 5 years amounting 93% and 72%, respectively. Cluster analysis identified 8 distinct patient subgroups principally defined by gender, age, kidney function and weight. The full cohort and all patient subgroups displayed the highest survival at a temperature of 32°C. Given these associations, further prospective randomized controlled trials are needed to ascertain optimal patient temperatures during CPB.
