Comparison of the hemodynamic changes following tourniquet use in orthopedic surgeries in two different age groups

Abstract

Over time, several physiological changes have been made to improve the safety of tourniquet use, but there are still no precise guidelines, partly because there is no collective agreement. The aim of this study is the comparison of the hemodynamic changes following tourniquet use in orthopedic surgeries in two different age groups. Materials and Methods: This study was a clinical trial and the target population was all patients over 18 years of age who had an indication for upper or lower limb orthopedic surgery with the possibility of using a tourniquet at Shohada Hospital of Tabriz in 2023-2024. 260 people were included in the study. The sampling method was a census. The determined sample size was divided proportionally between patients under 65 years of age and over 65 years of age (65 patients in each group) and randomization was performed separately within each age group using a block randomization method with blocks of 4 and 6. All patients were examined in the ward and a complete history was taken and if they had consent and had an indication for surgery, they were included in the study. A questionnaire designed for this purpose was filled out for all patients. After entering the operating room and performing routine ward monitoring including: SBP, DBP, MBP, HR, SaO2, the patients were placed under the same anesthesia. The questionnaire recorder and the surgeon were unaware of the tourniquet pressure. A standard calibrated tourniquet was used in all surgeries. The patient's systolic blood pressure was determined before filling the tourniquet, and then 100-130 mmHg was added to it in the lower limb and the tourniquet was filled with that pressure. Also, in the upper limb, the tourniquet was filled 50-70 mmHg above the systolic blood pressure and the variables studied were recorded in the questionnaire. If the surgeon complained of bleeding at the surgical site, 20% was added to the tourniquet pressure. Results: In this study, among hemodynamic factors, the frequency of increase in all hemodynamic variables, including SBP (P=0.001), DBP (P<0.001), MAP (P<0.001), and HR (P=0.002), compared to before tourniquet filling, was significantly higher in patients with routine tourniquet pressure over 65 and under 65 years of age than in patients with modified tourniquet pressure over 65 and under 65 years of age. Also, the decrease in SBP compared to baseline (P=0.001) in patients with modified tourniquet pressure over 65 and under 65 years was significantly higher than in patients with routine tourniquet pressure over 65 and under 65 years, and the increase in HR compared to baseline (P=0.004) in patients with routine tourniquet pressure over 65 and under 65 years was significantly higher than in patients with modified tourniquet pressure over 65 and under 65 years. Among hemodynamic factors, there was no statistically significant difference in the onset time of changes in any of the variables SBP, DBP, MAP, and HR after tourniquet filling compared to before tourniquet filling and baseline between the routine and modified tourniquet pressure groups in people over 65 years of age and under 65 years of age (P<0.05).