DEX, a long-acting glucocorticoid with strong anti-inflammatory characteristics, is widely used to reduce perioperative inflammatory response, relieve postoperative pain and fatigue and reduce the incidence of PONV13,14. Some randomised controlled trials and meta-analyses have demonstrated the efficacy of DEX in preventing inflammatory stress, with no reports of increased complications, such as SSI or GIB after THA5,14,15,16. However, postoperative pain sometimes occurs even after the administration of a dose of DEX after 24 h9. Based on these findings, we considered that an additional dose of DEX may still be required after 48 h.
Postoperative hypothermia is a common complication that is easily ignored after surgery. This hypothermia is often caused by operating room hypothermia, anaesthesia, infusion, or surgery17,18. In postoperative hypothermia, core body temperature after anaesthesia generally ranges from 32 to 36 °C, but its incidence has been rarely reported and fluctuates markedly from 20 to 74%19,20. Hypothermia disrupts and aggravates the coagulation mechanism, increases perioperative blood loss and the risk of blood transfusion, reduces the postoperative recovery rate and degree of patient satisfaction, and even increases the risk for postoperative death17,21,22. The effect of DEX combined with aggressive warming has not been mentioned in the accelerated rehabilitation surgery strategies for THA. We hypothesised that a repeat dose of DEX at 48 h postoperatively along with aggressive warming during surgery may reduce postoperative fatigue, accelerate postoperative recovery, and improve patient satisfaction.
Common complications of THA include pain and PONV. Moderate-to-severe postoperative pain, which is most prevalent during the first three days after surgery, is closely related to inflammatory responses23. DEX can effectively reduce the postoperative inflammatory response and postoperative pain9,24,25. However, only the first 24 h after surgery have been examined in most of the studies9,24. Lei et al.9 conducted a prospective randomised controlled trial in patients who received THA. DEX (10 mg) administered at the beginning of anaesthesia and 24 h after anaesthesia effectively reduced postoperative inflammatory response and pain. However, many patients still had obvious pain and other discomfort on the third day after surgery. In a prospective study conducted in The West China Hospital of Sichuan University, repeated doses of DEX up to 48 h could further reduce pain and inflammation after THA; further, repeated application of DEX (10 mg) at 48 h after THA on POD3 was found effective14. In the present study, postoperative inflammation and pain levels of patients in group B were significantly lower than those in group A, thus confirming the effectiveness of repeated administration of DEX (10 mg) 48 h following surgery. However, we failed to detect a difference in the pain levels between group A and B participants at rest on POD3. We believe this could be attributed to the generally lower pain score at rest on POD3; the pain perception of the patients might not have been sensitive enough to detect the potential relief of pain at rest. PONV is a common complication after THA that affects the degree of patient satisfaction, delays postoperative recovery, and increases psychological and economic burdens26. In this study, no difference in PONV was detected among the three groups after surgery. The most probable reason for this would be that most cases of PONV occurred within 24 h after surgery, consistent with the observations in a previous study27. Therefore, the repeated application of DEX at 48 h may have had a limited effect on PONV reduction.
Thermal intervention has been indicated to effectively reduce perioperative blood loss, thus reducing the blood transfusion rate17. In a prospective trial, Reina et al.28 observed over 900 patients who underwent THA to explore the effects of tranexamic acid (TXA) under mild hypothermia and recorded the occurrence and frequency of blood transfusions and associated complications. The incidence of hypothermia in THA was as high as 84.2%; however, mild hypothermia did not affect the efficacy of TXA, which effectively reduced perioperative blood loss and blood transfusion rate. Winkler et al.29 studied the changes in core temperature, blood transfusion rate, and length of hospital stay in 143,157 patients during THA. The core temperature decreased during the first hour and increased thereafter. Nearly 50% of the patients had a low core temperature below 36 °C, while that of 20% of the patients was below 35.5 °C for more than 1 h. Moreover, 20% of patients had a core temperature below 36 °C, among which 8% had a core temperature below, 35.5 °C for more than 2 h. Kurz et al.19 reported that maintaining normothermia intraoperatively probably decreased the incidence of infectious complications in patients undergoing colorectal resection and shortened their hospital stay. Hypothermia is a normal phenomenon during the first hour after anaesthesia even at high body temperatures, which confirms that hypothermia would increase the transfusion rate, and aggressive warming could reduce blood loss during THA and reduce complications. In our study, the average temperature of patients in group C was significantly higher than that in groups A and B at 30 and 60 min after the operation and at the end of the operation, because of thermal intervention, thus confirming the effectiveness of the thermal insulation measures. We statistically analysed the IBL, PDV, and transfusion rates of the patients in the three groups. The IBL and PDV of patients in group C were (252.00 ± 43.43) mL and (421.30 ± 44.34) mL, respectively, which were significantly lower than the corresponding values of patients in groups A and B (P < 0.001), consistent with the findings from previous studies17,29. Therefore, we conclude that warming intervention is effective in reducing IBL and PDV in THA. However, no difference was found in blood transfusion rates among the three groups. This could be attributed to surgical improvements, choice of anaesthesia technology, and optimal management of blood conservation during the perioperative period of THA. Owing to these aspects, the blood transfusion rate of conventional THA has gradually decreased, and no difference could be detected among the three groups.
ROM, p-LOS, and ICFS can be important reference indicators to comprehensively reflect the postoperative recovery rate of patients13. Improving patient satisfaction is an urgent issue to resolve. In a meta-analysis of the relationship among pain, sleep, and fatigue, Whibley et al. 30 pointed out that these three factors influence and interact with each other. Only when each factor is positively controlled can a virtuous circle be established to promote early recovery of patients, shorten the average length of stay, and improve their degree of satisfaction. In our study, ROM and ICFS of patients in group B were superior to the values of patient in group A on POD3 (P < 0.05). Thus, we could administer an additional dose of DEX at 48 h to effectively relieve fatigue and improve the ROM. By comparing groups B and C, we conclude that DEX combined with aggressive warming can effectively relieve postoperative fatigue and improve short-term ROM. Based on this conclusion, we considered that the use of aggressive warming during the operation reduced the incidence of postoperative hypothermia and chills as well as perioperative blood loss, thus improving the recovery speed of the body and the initiation of postoperative rehabilitation of patients29. However, there was no significant difference in the p-LOS among the three groups; nevertheless, we presume that the stay was short enough that the effect of an additional dose of DEX was not obvious. In addition, the satisfaction degree of patients in the three groups did not differ significantly (χ2 = 8.12, P = 0.23); thus, one additional dose of DEX may not significantly improve the satisfaction of patients (group A vs. B). However, based on aggressive warming, adding an additional dose of DEX at 48 h did significantly improve patient satisfaction unexpectedly (group A vs. C, χ2 = 8.10, P = 0.04). Therefore, aggressive warming can be deemed a necessary procedure.
In our study, no serious complications, including SSI or GIB, occurred in any patient. However, the potential for SSI and GIB with DEX use is not negligible31. Hannon et al.32 performed a meta-analysis that demonstrated that single or multiple doses of intravenous DEX help reduce postoperative pain, opioid consumption, and PONV. However, the analysis highlighted the insufficient evidence on the risk of postoperative adverse events. Owing to the relatively small sample size (50 cases in each group) and short follow-up time (3 months), our study may lack sufficient strength to measure events that are infrequent33. Therefore, our findings should be interpreted with caution, and further large-scale prospective studies are necessary.
This study has some limitations. First, the follow-up time was too short to adequately assess the efficacy and safety of DEX after the three-month-follow-up. Second, as mentioned, we included 50 patients in each group and the small sample size weakened the persuasive power of the study. Third, the complications in this study focused only on SSI and GIB. Other complications, such as blood glucose changes, were not closely followed. Finally, there is a scope for errors during axillary temperature measurements.