A clinical study of the efficacy of automated intermittent boluses for continuous fascia iliaca block

To compare two different regimens of continuous ultrasound-guided fascia iliaca compartment block (FICB) for postoperative analgesia after total hip arthroplasty (THA).Approved by the Peking University Third Hospital ethics committee, sixty patients undergoing selective single total hip replacement in Peking University Third Hospital from May.2015 to Mar.2016 were included. Before neuraxial block, continuous ultrasound-guided FICB were administered. Patients were randomly divided into the continuous infusion group(n=30) and the automated intermittent boluses group(n=30). 10 ml/h of 0.2% ropivacaine was continuously infused for 48 hours in the continuous infusion group. 10 ml of 0.2% ropivacaine was automated injected every 60 mins in the automated intermittent boluses group. Numerical Rating Pain Scale(NRPS)was used to assess pain intensity at 4, 8, 12, 24, 36, 48 h after block at rest and during functional exercise. The usage of pethidine postoperatively, the incidence of opioid related adverse effect and patient satisfaction scores at 48 h were also recorded.The pain score at rest 8, 12, 24, 36 h of the automated intermittent boluses group were 2 (1-3), 2 (1-3), 2 (1-3), 2 (1-3) score, which were lower than the continuous infusion group: 4 (2-6), 3 (2-5), 4 (3-5), 2 (1-4) score, the differences were statistically significant (Z=-6.493, -6.267, -6.235, -3.244, all P<0.05). The pain score during active and passive functional exercise at 8, 12, 24, 36 h of the automated intermittent boluses group were 4 (3-5), 4 (3-5), 2 (1-3), 1(0-3) score, which were lower than the continuous infusion group: 6 (4-7), 5 (4-7), 4 (2-6), 4 (2-5) score, the differences were statistically significant (Z=-6.499, -6.499, -5.081, -6.667, all P<0.05). The usage of pethidine postoperatively and the incidence of opioid related adverse effect of the automated intermittent boluses group were 10.0% and 3.3%, which were lower than the continuous infusion group: 33.3% and 26.7% , the differences were statistically significant (χ(2)=5.057, 4.500, all P<0.05). Patient satisfaction score at 48 h of the automated intermittent boluses group was (8.3±0.7)score, which was higher than the continuous infusion group: (7.4±0.7)score, the difference was statistically significant (t=-5.632, P<0.05).Both regimens can provide effective analgesia after total hip arthroplasty. Compared with the continuous infusion group, the automated intermittent boluses group for continuous fascia iliaca block can provide better analgesic effect , with less remedial analgesia.