Hemodynamic Effects Of General Anesthesia In Elderly Undergoing Total Hip Replacement

Total hip replacement (THR) is primarily performed on elderly patient of femoral head necrosis and femoral neck fracture with the striking feature of severe damage, more blood loss, and in need of bone cement. The population at risk is, by and large, elderly who often have multiple comorbidities. Thus, significant perioperative morbidity and mortality may occur in this population. Therefore the selection of anesthetic techniques is key point to ensure anesthetic security, more successful operations and decrease perioperative morbidity and mortality. General or regional (spinal and epidural) anesthetic techniques are used in the procedure, but which one offers a significantly better effect over the other has been controversial. Updated evidence-based guidelines for managing elderly patients with hip fractures support the use of regional anesthesia over general anesthesia when possible. However researchers have found no superiority in regional anesthesia recently because of increased levels of anesthesia, operation and perioperative care. Relevant research has assembled in the effects of regional anesthesia on perioperative blood loss and transfusion requirement, hemorheology, postoperative complications and perioperative morbidity and mortality. In the study, we collect 143 THR cases with the population older than 65 yr and retrospectively study the effects of general anesthesia and epidural anesthesia on hemodynamic changes and correlated influential factors in elderly patients undergoing THR.Objective To study the effects of general anesthesia and epidural anesthesia on hemodynamic changes and correlated influential factors in elderly undergoing THR and discuss the feasibility and safety of general anesthesia for the elderly undergoing THR to provide clinical evidence for anesthetic techniques selection.Methods 143 patients of ASAⅡ～Ⅲwhose age ranged from 65 to 83 yrs were collected. They have undergone THR, including general anesthesia group (group G, n=54) and epidural anesthesia group (group E, n=89). Data of blood pressure, heart rate, SpO2 were recorded right after they entered OR (operating room) (T0), when they got induction (T1), before (T2) and after (T3) bone cement implantation, stitching wound (T4) and turn over (T5). Ephedrine and atropine dosage, blood loss, fluids transfusion, operative time and postoperative complication were also monitored and recorded. All data was analyzed by SPSS 14 statistical software and expressed as X±s. Paired samples t-test was used within one group, Chi square test and two independent sample t-test were used to compare the two groups. P<0.05 displays a significant difference.Results 1.Blood pressure was markedly decreased after anesthesia (P<0.05) in both two groups, while there is no significant difference between two groups at T1 and T2. Blood pressure decreased 12.8～20.5 mmHg further after bone cement implantation (T3)(compared to T2, P<0.05) in two groups, and blood pressure in group E decreased more than that of group G (P<0.05); Blood pressure decreased suddenly when patients were turned over from lateral to supine position (compared to T4, P<0.05) in group E, but it was steady in group G, there was significant difference between two groups (P<0.05); 2. In group G, heart rate was obviously slower at T1,T2 and T3 than T0 (P<0.05), then it returned to the level of T0 at the end of the surgery (T4, T5). In group E, heart rate 10 min after epidural administration (T1) was significantly faster than T0 (P<0.05), but it was slower after bone cement implantation (T3) than that of before (T2) (P<0.05). The difference between the two groups in heart rate after anesthesia was notable (P<0.05). 3. There was no significant difference in blood loss, while the fluid transfusion in group E was 313.6 ml more than that of group G (2113.6 ml versus 1800.0 ml). 4. Serious hypotension (systolic blood pressure decreased more than 30% of base level) mostly appeared at 1～2 min just after bone cement implantation. Hypotension occurred to 14 patients (26%) in group G and 45 (51%) in group E, the result was significantly different between the two groups (P<0.05). 5. The result of atropine administration was not obviously different, but the number of patients needing ephedrine in group E was significantly different from that of group G (35% versus 62%, P<0.05). 6. The operative time of group E was 21 minutes longer than group G (P<0.05). 7. There were no significant differences between the two groups throughout the study period in terms of SpO2, postoperative myocardial ischemia, pneumonia, cognitive dysfunction and ileus.Conclusion 1. General anesthesia offers steady hemodynamics and less incidence of hypotension, so the risk of inadequate tissue perfusion and organ embolism is decreased. 2. General anesthesia probably inhibits the endocrine hormone caused by surgical stress reaction. Meanwhile not only does general anesthesia avoid excessive fluids transfusion, but it also reduces vasoactive agent requirement, so general anesthesia shows superiority in cardiac protection. 3. Bone cement implantation syndrome is easy to induce adverse events, such as severe bradycardia and cardiac arrest. The cement reaction is slightly under general anesthesia and the inducement of heart failure and sudden death decreased.