Effects of intraoperative hypothermia on stress hormon response in surgical patients

Background/Aim. Surgical stress itself, as well as hypothermia induced by general anaesthesia, and low ambient temperature activate stress hormone response with changes in catecholamines and counter regulatory hormones. The aim of this study is to investigate the acute hormone stress response in patients who underwent major surgical procedures and the efficiency of external and internal warming methods in alleviation of these changes. Methods. 60 patients who underwent major open abdominal surgical procedures were randomly divided in 4 groups: control non-warmed (C), externally warmed using forced-air warming mattress (W), internally warmed using intravenous amino acids (A), and warmed with combination of external and internal method (A+W). Oesophageal temperature was used as measure of core temperature. Blood samples for hormone measurement were obtained in 2 time points for catecholamines: 90 minutes before and 120 minutes after finishing the surgery; and in additional 2 time points for cortisol, prolactin and testosterone: (24 and 48 hours after surgery). Results. In W and A+W group the temperatures did not significantly differ between time points, but in C and A groups decreased constantly, with statistically significant difference between the anaesthesia induction and 120th minute (35,61±0,42 vs 33,86±0,71 °C; p<0,000 and 35,81±0,54 vs 34,45±0,41 °C; p<0,000 , respectively). Catecholamine concentrations in all groups showed significant increase during surgery, with highest values recorded in non-warmed group (777,07±800,08 after vs 106,13±89,63 pg/mL before surgery for epinephrine and 1349,67±984,16 vs 580,53±465,38 for norepinephrine, p<0,000). Concentrations of cortisol and prolactine also showed significant increase at the same time point, with tendency to normalization after 48 hours. Contrary, testosterone concentrations showed decrease after 120 minutes without normalization throughout the entire period of observation. Except for testosterone, changes in all stress hormones were attenuated in warmed groups compared to controls. Conclusions. Regarding both features of surgical stress investigated in this study (hypothermia and stress hormone response), combination of endogenous amino acid-induced hermogenesis and external air warming mattress is most effective.