Comparison of the effects on thermoregulation of lung protection ventilation and traditional high tidal volume ventilation on thermoregulation

Objective: Perioperative hypothermia is unintended fall of patient temperature and this led to many side effects on patients. The aim of this study is to compare temperature loss by mechanical ventilation types with restriction other factors effecting body temprature. Materials and methods: Approval for the study was granted by the Ethics Commitee of Afyon Kocatepe University (no:58, dated 11.11. 2016) and written informed consent was obtained from each patient. A total of 40 patients with American Society of Anesthesiologists (ASA) physical status I–II, aged 20- 65 years, undergoing lomber disk surgery were enrolled in this study. The patients were randomly allocated into two groups: Lung protective Ventilation Group (Group A) and Classical Convantionel Mechanical Ventilation Group (Group K). Standart anesthesia induction was performed for two groups. After intubation thermometers placed to patients for measuring core temperature. Also two temperature probes were installed to forearm and fingertip for measuring peripheral temperature. Intermittent temperature measurements were recorded throughout the operation. At the minute that the fingertip temperature was lower than the temperature in the forearm, the patient was interpreted as developing peripheral vasoconstriction, and at that minute the patient's internal temperature was recorded as the vasoconstriction threshold. In both groups, the temperatures of the operation room temperatures and the liquids supplied were kept constant. PEEP of 5 mmHg with 6ml/kg tidal volume was applied to lung protective ventilation group (Group A) patients. In classical mechanical ventilation group (Group K) patients, 8-10 ml / kg tidal volume was applied without PEEP, with peak pressures not exceeding 30 mmHg. - 65 - hypertension were excluded, in addition to those we need to use vasoactive drugs for hemodynamic stability were exluded too. Results: No significant differences were found in the age, heigh, weight, anesthetic duration, and the total fluid injection between the two groups. There was also no significant difference between room temperatures and hemoglobin values for operation. There were no patients who developed hypotension during the operation or who were left out of the study for another reason. There was no significant difference between the number of patients with peripheral vasoconstruction and the time of vasoconstriction development (vasoconstriction threshold) in both groups (p=0.33). There was no significant difference between groups heat loss during operation. Discussion and Conclusion: The application of PEEP with lung protective ventilation has no adventages to high tidal volume classical mechanical ventilation over the keeping final core temperature. We believe that further studies should be conducted with wider patient groups on the subject, as compared with publications showing that PEEP administration improves peripheral vasoconstriction earlier and has a more positive outcome in protecting the patient's temperature. Keywords: Lung Protective Ventilation, Positive End Expratory Pressure (PEEP), Perioperative Hypothermia.