Research Of Dexmedetomidine Patient-controlled Sedation In Spinal-epidural Anesthesia For Lower Limb Surgey

OBJECTIVETo investigate the feasibility of dexmedetomidine patient-controlled sedation inspinal-epidural anesthesia for lower limb surgey, and observe its safety and effectiveness.Preliminary study the correlation between Narcotrend and dexmedetomidinepatient-controlled.METHOD(1) Feasibility Research of Dexmedetomidine Patient-controlled Sedation in CombinedSpinal Anesthesia for Lower Limb SurgeryA total of160cases of ASAⅠ~Ⅱ, lower limb surgery patients as subjects, dividedinto PCS group (82cases) and conventional group (75cases). After combined spinalanesthesia, the PCS group began patient-controlled sedation with dexmedetomidine,loading dose2ml,background infusion volume1.5ml/h, single dose0.5ml, lock time20s.Conventional group according to the instructions infusion dexmedetomidine,loading dose1μg/kg, maintenance dose0.5μg·kg-1·h-1).Recorded PCS group and C group of HR MAP, SpO2, Ramsay sedation score, airwayscore (Airway) at the time of before pumped drug (T0), after pumped drug1min (T1),3min (T2),5min (T3),7min (T4),10min (T5), the beginning of surgery (T6), after thesurgery began10min (T7), end of surgery (T8). PCS group of patients without pressingPCS device within1min, were considered to achieve appropriate sedation. If BIS less than80, the regular group of patients were considered entering the appropriate sedation state.(2) Clinical Applications of Dexmedetomidine Patient-controlled Sedation inSpinal-epidural Anesthesia for Lower Limb SurgeryChoose150cases ASAⅠ~Ⅲ, lower limb surgery with spinal-epidural anesthesia,randomly divided into patient-controlled sedation group (PCS group) and control group(group C),75cases each group. Open peripheral venous access after entered the operatingroom, infusion-demand balanced salt solution and artificial colloid solution, connect the monitor to monitor BP, HR, SpO2. At L3-4lumbar intervertebral space punctured and madespinal-epidural anesthesia, injection of0.5%bupivacaine10~15mg (0.75%bupivacaine2mL+10%glucose1mL) to subarachnoid, block-level adjustment about at T10.After the block-level fixed, C group patients with constant speed (10mL/h) pumpedsaline as a placebo. PCS group patients used electronic pump (Rythmic Plus)patient-controlled sedation, the drug was dexmedetomidine, and formulated at aconcentration of4μg/mL, the parameter was set to: load2mL, background transfusions1.5mL, single dose0.5mL, lock time20s.Observed PCS group of pressing times/effective times (N/E), dexmedetomidinedoses (Dose). Recorded PCS group and C group of HR MAP, SpO2, Ramsay sedationscore, airway score (Airway) at the time of before pumped drug (T0), after pumped drug1min (T1),3min (T2),5min (T3),7min (T4),10min (T5), the beginning of surgery (T6),after the surgery began10min (T7), end of surgery (T8).(3) The Correlation of Narcotrend and Patient-controlled Sedation of DexmedetomidineA total of40patients with lower limb surgery in our hospital were selected. UntilCSEA block fixed, the electronic pump ran the patient-controlled sedation ofdexmedetomidine. The parameter of electronic pump was set: load dose2ml+backgrounddose1.5ml/h+single dose0.5ml+locktime20s, and then connected the Narcotrend tomonitor patient’s EEG of sedation depth. Recorded the heart rate, mean arterial pressure,pressing times, effective times, OAA/S sedation scores and NI values.RESULT(1) Research of Patient-controlled Sedation of Dexmedetomidine in Combined SpinalAnesthesia for lower limb surgeryThere were not significantly difference in two groups of general information. Twogroups of heart rate, mean arterial pressure (MAP) compared no significant difference,P>0.05. Compared with T0, two groups of patients’ heart rate at T1~T8were significantlydecreased, MAP at T1~T3is gradually increased, T5~T8is gradually reduced, airway scoreand BIS at T3~T7was significantly decreased, P<0.05. Compared with the conventionalgroup, the patient-controlled sedation group at T1~T8airway scores were not significantlydifferent, at T3~T7BIS significantly higher (P<0.05). The end of surgery, thedexmedetomidine doses of the patient-controlled sedation group and the conventionalgroup were (16.1±3.0) ml and (26.7±4.6) ml, BIS values were (95.6±3.2) and(93.3±2.7). There was one case appear airway score4points in both groups. The airway score nosignificant difference in contrast, and did not appear serious adverse reactions of airway.Two group of oxygen saturation (SpO2) at each time were higher than96%, had nosignificant difference in contrast, P>0.05. There was one patients in conventional groupappear SpO2minimum of92%, due to airway obstruction after the patient fell asleep. Andawaked the patient then the SpO2could be increased to100%. Others could maintain SpO2between96to100percent, no patients need intervention.(2) Clinical Applications of Dexmedetomidine Patient-controlled Sedation inSpinal-epidural Anesthesia for Lower Limb SurgeryThere were not significantly difference in two groups of gender, age, weight, type ofsurgery and operative time.After the patient-controlled sedation began, the HR of PCSgroup decreased. The decreasing range was within30%. Compared with T0, PCS grouppatients’ HR at T1~T8slower significantly (P <0.05). Compared with group C, PCS grouppatients’ HR at T1~T8slower significantly (P <0.05).PCS group after patient-controlled sedation began, MAP biphasic trend decreasedafter an initial increase. When comparing with T0, PCS group patients at T1~T3MAP wassignificantly higher (P <0.05); MAP at T5~T8was significantly lower (P <0.05), but thedecline was less than20%. Compared with C group, PCS group patients at T5~T8MAPwas significantly lower (P <0.05).Before the began of PCS group dexmedetomidine patient-controlled sedation, therewere64patients with Ramsay score of1; after that, at the time T3~T7there were51,72,74,73,72patient respectively with Ramsay score of3to4; Ramsay sedation scoregreater than5did not appear.After the began of PCS group dexmedetomidine patient-controlled sedation, theinterval of pressing times was [17,317], with an average (112.10±65.79) times. Theinterval of effective pressing times was [9,63], and the average times was (21.00±9.07).The interval of drug of actual given was [9,25] ml, average (15.12±3.19) ml. The intervalof dose when sedation reach Ramsay3~4was [7,20] ml, average (11.29±2.16) ml.Theinterval of required time when sedation reach Ramsay3~4was [3,10] min, average (7.55±1.53) min.After the began of PCS group dexmedetomidine patient-controlled sedation, Ramsayscore and Airway score gradually increased, and before surgery recovered to pre-sedationlevel of patient-controlled sedation. Ramsay sedation score up to5points was2cases, Airway score up to4points was3cases. PCS group of patients with Ramsay score scoreand Airway linear correlation.PCS group’s HR and cumulative dose, pressing times, effective pressing timesshowed a linear correlation respectively r=0.8813,0.9100,0.8183. Using multiple linearregression analysis the effect of cumulative dose, pressing times, effective pressing timesto HR, and considered that maximum effect to HR was effective pressing times, thecumulative dose followed, the pressing times of minimal effect.(3) The Correlation of Narcotrend and Patient-controlled Sedation of DexmedetomidineAfter the dexmedetomidine patient-controlled sedation began, the HR graduallydecreased. The MAP was biphasic trend of first increased and then decreased. The SpO2was no significant change and maintained at95%above.At T4point, the patient OAA/S scores up to3points and reached appropriatesedation, thereafter, remained relatively stable of sedation appropriate (OAA/S scores3to4). From T5point, NI values showed significantly decreased. When compared with thetime to reach the appropriate sedation, NI values laged time (3.1±1.8) min, and remainedrelatively stable of NI values (60to70) after the T7points.OAA/S scores and NI values reached a plateau time were (7.5±1.8) min and (13.1±3.4) min, OAA/S scores of1,2,3,4, respectively, corresponded roughly with NI values(95to100),(90to94),(65to89),(40to64). The correlation of OAA/S scores and NIvalues in the patient-controlled sedation of dexmedetomidine was y=-0.06x+7.71,r=0.58.The time of NI values significant decreased in the younger group and the elderlygroup were (10.2±1.6)min and (14.4±2.2)min. In T5~T9point, NI values of theyounger group was significantly lower than the elderly group. The dexmedetomidineconsumption in the younger group and the elderly group were (15.3±2.8)ml and (11.5±2.7)ml. After the patient-controlled sedation of dexmedetomidine began, the pressingtimes of (203.9±107.1) times, the effective times of (23.9±7.1) times, the actuallyadministration dose of (13.8±3.6)ml.CONCLUSION1.Dexmedetomidine patient-controlled sedation is feasibility and safety underparameter of load2ml, background infusion1.5ml/h, single dose0.5ml, lock time20s.2.Dexmedetomidine patient-controlled sedation in spinal-epidural anesthesia forlower limb surgey is effective and safety.It can achieve personalized medicine, avoid excessive sedation and inadequate sedation by the self-administered.3.There is linear correlation between NI values and dexmedetomidinepatient-controlled sedation depth. OAA/S scores of1,2,3,4, respectively, correspondedroughly with NI values (95to100),(90to94),(65to89),(40to64).