Lai Yuan, Zhang Jin, Li Kai
Objective To explore the effect and safety of dexmedetomidine with different ways of administration on nerve block anesthesia in elderly patients undergoing untensioned repair of inguinal hernia. Methods The elderly patients who underwent untensioned repair of inguinal hernia in Shenyang Fourth People′s Hospital from June 2017 to June 2019 and met the inclusion criteria were randomly divided into local nerve block by ropivacaine+dexmedetomidine group (local anesthesia group) and local nerve block by ropivacaine+intravenous pumping of dexmedetomidine group (local anesthesia+intravenous pumping group) using random number table. Local anesthesia group: 15-ml of solution obtained by a certain dose of dexmedetomidine （calculated by 1-μg/kg） diluted in a suitable volume of 0.9% sodium chloride injection+15-ml of 0.375% ropivacaine were injected locally among iliohypogastric nerve and ilioinguinal nerve under the guidance of ultrasound, and meanwhile 0.9% sodium chloride injection were pumped intravenously at the speed of 1-ml/(kg·h) until the end of operation. Local anesthesia+intravenous pumping group: a dose of dexmedetomidine (calculated by 1-μg/kg) was intravenous pumped, 30-ml of 0.375% ropivacaine were injected among iliohypogastric nerve and ilioinguinal nerve under the guidance of ultrasound 10-minutes later, and at the same time, dexmedetomidine was pumped intravenously at the speed of 0.25-μg/(kg·h) until the end of operation. The patients′ basic information including sex, age, body weight, body height, grade determined by American Society of Anesthesiologists Physical Status Classification, and the operation time were recorded. The changes of heart rate and mean arterial blood pressure (MAP) at different time points ［before anesthesia (T0), anesthesia completion (T1), beginning of operation (T2), 15-minutes after anesthesia (T3), 30-minutes after anesthesia (T4)］, the onset and maintenance time of sensory nerve block, the analgesic effect during the operation, the patient analgesia satisfaction score at the 24th hour after operation, the visual analogue scale (VAS) scores at 0, 3rd, 6th, 9th, and 12th hour after operation in resting state, and the occurrence of adverse reactions were compared between the 2 groups. Results The differences of basic information in patients between the 2 groups were not statistically significant (P>0.05 for all). The heart rate of patients at T2 and T3 in the local anesthesia+intravenous pumping group were lower than those in the local anesthesia group ［(62.55±5.66) beats/min vs. (76.70±6.47) beats/min, (53.83±5.07) beats/min vs. (74.98±5.40) beats/min, P<0.001 for both］. Intra-group comparison showed that the heart rate of patients at T2 and T3 were lower than that at T0 in the local anesthesia+intravenous pumping group ［(62.55±5.66) beats/min vs. (72.50±7.14) beats/min, (53.83±5.07) beats/min vs. (72.50±7.14) beats/min, P<0.001 for both］. The differences of MAP at different time points between the 2 groups and in intra-group comparison were not statistically significant (P>0.05 for all). The onset time of anesthesia in the local anesthesia group was shorter than that in the local anesthesia+ intravenous pumping group ［(5.2±1.1) min vs. (12.5±0.7) min, P=0.010］, while the maintenance time of anesthesia was longer ［(742.5±3.5) min vs. (631.0±1.4) min, P=0.010］. There were 38(95%), 2(5%), and 0(0) patients having good, fine, and bad analgesic effect in the local anesthesia group, and 30(75%), 8(20%), and 2(5%) in the local anesthesia+intravenous pumping group, respectively. The difference of analgesic effect between the 2 groups was statistically significant (χ2=6.541, P=0.038). The patients′ anesthesia satisfaction score at the 24th hour after operation in the local anesthesia group was higher than that in the local anesthesia+intravenous pumping group ［(9.5±0.7) vs. (7.0±1.4), P=0.030］. The VAS scores at 0, 3rd, 6th, 9th, and 12th hour after operation in resting state in the local anesthesia+intravenous pumping group were higher than those in the local anesthesia group (P<0.05 for all). Intra-group comparison showed that the VAS scores at the 5 time points above-metioned in the local anesthesia group were no statistically significant (P>0.05 for all), the VAS scores at 9th and 12th hour after operation in the local anesthesia+intravenous pumping group were higher than that at 3rd hour, the differences were statistically significant (P<0.05 for both). The dif- ference of the incidence of adverse reactions after operation between the 2 groups was not statistically significant (χ 2=0.697, P=0.410). Conclusions The analgesic effect of local injection of ropivacaine+dexmedetomidine is better than that of local nerve block of ropivacaine+intravenous pumping of dexmedetomidine. Thus the anesthesia program of local nerve block with ropivacaine+dexmedetomidine is recommended in the elderly patients undergoing untensioned repair of inguinal hernia.
