Clinical research on the dexmedetomidine applied for patient-controlled sedation during the lower limbs operation under combined spinal-epidural anesthesia

To investigate the effect and safety of dexmedetomidine applied for patient-controlled sedation under combined spinal anesthesia. 150 cases who would be implemented lower limbs operations were randomly divided into patient-controlled sedation group (Group PCS) and control group (Group C) and 75 cases for each group. The ages of patients were between 18 and 65 years old and patients were with American Society of Anesthesiologists (ASA) or level. After being implemented combined spinal anesthesia, patients of Group PCS were undergone patient-controlled sedation by using dexmedetomidine (4 mu g/mL) with 2mL of load quantity, 1.5ml of background infusion quantity, 0.5mL of single dose and 20s of locking time; patients of Group C were constantly infused the normal saline at the rate of 10ml/h by pump injection. HR, MAP, SpO2, Ramsay sedation scores and airway scores before the pump injection (To), 10 min (T-1), 3 min (T-2), 5 min (T-3), 7min (T-4) and 10min (T-5) after the pump injection, at the beginning of operations (T-6), 10min(T-7) after the operations and in the end of operations (T-8) of patients of two groups were respectively recorded. At the same time, the pressing numbers and doses of dexmedetomidine of patients of Group PCS were observed. Compared with the HR at To, HR in Group PCS obviously decreased between T1 and T-8 (P<0.05). Compared with HR in Group C, HR in Group PCS obviously slowered between T1 and T-8 (P<0.05). Compared with the MAP at T-0, MAP in Group PCS gradually increased between T-1 and T-3 and gradually reduced between T-5 and T-8 (P<0.05). MAP between T-5 and T-8 in Group PCS were significantly lower than those in Group C (P<0.05). Between T-3 and T-7, there were 51, 72, 74, 73, 72 patients in Group PCS whose Ramsay scores were from 3 to 4 points respectively. During the process of patient controlled sedation of patients in Group PCS, the pressing times were 112.10 +/- 65. 79 times. The effective pressing numbers were 21.00 +/- 9. 07 times. The patient-controlled dosages were (15.12 +/- 3.19) ml; The dosages were 11.29 +/- 2.16m1 when the level of sedation achieved 3 to 4 scores in Ramsay sedation scores; And the required time to achieve 3 to 4 scores in Ramsay sedation scores was 7.55 +/- 1.53 min. In the lower limbs operations, the usage of dexmedetomidine applied for patient-controlled sedation under combined spinal anesthesia can effectively approach to the personalized medicine and is effective in clinical application.