ObjectiveTo investigate the effects of B-ultrasound-guided lumbar plexus block("clover" method) combined with bispectral index(BIS) in monitoring the laryngeal mask general anesthesia with different depths of anesthesia in the perioperative period of elderly total hip arthroplasty(THA) patients.

MethodsA total of 82 elderly patients treated with THA were divided into the group A and group B according to the random number table method(41 cases in each group).On the basis of ultrasound-guided lumbar plexus block("clover" method), the BIS value in group A and group B were maintained at 55-65 and 40-50, respectively.The resting pain score and movement pain score(VAS) before and after 6, 12, 24 and 48 h of operation, perioperative stress levelsincluding the heart rate(HR), respiratory rate(RR) and mean arterial pressure(MAP), self-control analgesia after surgery(including the postoperative first application time, times of use, effective compression rate and sufentanil dosage), postoperative recovery(including waking time, extubation time and directional force recovery time), preoperative and intraoperative cognitive function(MMSE) score before and after 1, 3 and 7 days of operation in two groups were counted.

ResultsFor pain and self-controlled analgesia, the resting VAS and movement VAS scores in two groups after 6, 12, 24 and 48 h of surgery were decreased compared with before operation, and the difference of which between two groups was not statistically significant(P>0.05).The differences of the first application time, times of use after 0-24 h and 24-48 h of operation, effective press rate and sufentanil dosage between two groups were not statistically significant(P>0.05).For surgical stress, the levels of RR, HR and MAP in two groups at T₁, T₂, T₃ and T₄ were lower than those at T₀(P < 0.05), but the difference of which between two groups was not statistically significant(P>0.05).For postoperative recovery, the reults of postoperative statistical results showed that the recovery time, extubation time and orientation recovery time in group A were shorter than those in group B(P < 0.01).For cognitive function, the MMSE scores in two groups decreased at 1 day after operation compared with before opertaion(P < 0.05).The differences of the MMSE scores after 1, 3 and 7days of operation between two groups were not statistically significant(P>0.05).For pulmonary infection and adverse reactions of anesthesia, the differences of the incidence rates of lung infection and adverse reactions between two groups were not statistically significant after operation(P>0.05).

ConclusionsThe "clover" method B-ultrasound-guided lumbar plexus block combined with implementation of BIS monitoring shallow laryngeal mask general anesthesia can achieve the same anesthetic analgesia effect as deep laryngeal mask general anesthesia.It does not increase the risk of cognitive impairment, pulmonary infection and adverse reactions to anesthesia, and is conducive to postoperative recovery of patients.It can be used appropriately according to the actual situation.