Effect of different thermal interventions on body temperature in elderly patients following total hip replacement operation

Abstract

Objective To investigate the effect of different thermal interventions on body temperature and thermal comfort of patients undergoing total hip replacement operation. Methods Inclusion criteria: diagnosis of femoral neck fracture by imaging examination, age not less than 65, American Society of Anes- thesiologists (ASA) statusⅠ~Ⅱ, no difficulty in verbal communication, postoperative anesthesia recovery room (PACU) for anesthesia resuscitation. Exclusion criteria: abnormal coagulation function, suffering from ear canal disease, thyroid dysfunction, immune dysfunction, pathological obesity, patients with fever or infection four weeks before surgery. A total of 120 patients with total hip replacement operation were randomly divided into four groups, 30 cases in each group: forced-air warming system group (group A), fluid warming group (group B), forced-air warming system combined with fluid warming group (group M) and control group (group C). The tympanic membrane temperatures at admission (T1), skin incision (T2), the end of operation (T3) and exited from operating room (T4) were recorded and compared among the four groups. The incidence of inadvertent perioperative hypothermia and shivering, thermal comfort and the durationin post-anesthesia care unit (PACU) were recorded and compared.The Kolmogorov-Smirnov method was used first to test the normality of all the variables. Variance analysis and t-test were used to analyze the normal distribution data, the Mann–Whitney U-test was used to analyze the skewed distribution data. Chi-square test and Fisher's exact probability method were used to analyze thenumeration data. Results The tympanic membrane temperature at T1 had no statistical significance among four groups ( F=0.461, P>0.05). The temperature in the group A (T2-T4: t=11.504, 10.056, 14.205)and group M(T2-T4: t=13.710, 12.086, 19.101) had statistically significant difference when compared with that in group C in T2-T4 (P 0.05) and also no difference in group A and group M ( P>0.05). There was no significant difference of inadvertent perioperative hypothermia, shivering, PACU duration and the thermal comfort score in group C and group B (P>0.05). Group A and group M had lower incidence of inadvertent perioperative hypothermia (group C vs A: χ2=5.963, group C vs M: χ2=4.356)and shivering (group C vs A: χ2=6.667, group C vs M: χ2=6.667)than those in group C (P<0.05), and the PACU duration (group C vs A: t=-3.701, group C vs M: t=-4.023)in group A and group M were significantly shorten than those in group C (P<0.05), the thermal comfort (group C vs group A: U=206.500, group C vs group M: U=211.500)score was higher in group A and group M than thosein group C (P<0.05). Conclusion The forced-air warming system can maintain the patient’s body temperature, shorten the PACU duration, reduce the occurrence of shivering, improve the thermal comfort, and provide an effective temperature protection strategy for elder patients when undergoing total hip replacement operation. Key words: Arthroplasty, replacement, hip; Tympanic membrane; Body temperature; Patient comfort