The Research On Relative Between Preoperative Pain Tolerance And TCI Sedative Dose Of Propofol

Objectives To explore correlative changes between preoperative pain tolerance and propofol TCI sedation, and provide information to administrate anesthetics for Individual.Methods Seventy patients(ASAⅠ～Ⅱ)aged 25～79, undergoing electively abdominal surgery were included. Pain sensitivity was measured by electrical stimulation preoperatively, including pain threshold and pain tolerance; A Sate-Trait Anxiety Inventory was used to assess patients'anxiety before surgeries. Electrocardiogram(ECG) and heart rate(HR), pulse, spo2 , arterial pressure(including systolic blood pressure, diastolic blood pressure, mean arterial pressure) were recorded before induction and remifentanil injection. General anesthesia was induced intravenously with a TCI of propofol and remifentanil injection, and ringer lactate was infused intravenously at 10ml/kg before anesthesia. Patients breathed spontaneously before their spo2 dropped to 85% and sedative depth was assessed to 1 point by OAA/S. The target-controlled concentration of propofol in effect site was set at 1μg/ml until it was maintained equilibrium for 2min between the target-controlled concentration in plasma and the target-controlled concentration in effect site. Then the target-controlled concentration in effect site was increased by 0.5μg/ml each time until OAA/S reached to 1 point. Endotracheal intubation was executed when Vecuronium was injected at 0.1 ml/kg and the concentration of TCI of remifentanil is 4ng/ml. Blood pressure and heart rate, spo2, apnea duration were recorded respectively after the patient was sent into operating room and calmed down for 10 min, and when the target-controlled concentration in plasma and the target-controlled concentration in effect site reached balance every time after the concentration in effect site was increased. At the same time, sedative depth was assessed by OAA/S. The target-controlled concentration in effect site, blood pressure, heart rate were recorded respectively when sedative depth was assessed as 3 point and 1point. Blood pressure and heart rate were recorded at baseline, after intubation and skin incision to calculate their means as indicators of blood pressure and heart rate respectively. Statistical results of measurement data analyzed by SPSS13.0 were represented by mean plus or minus standard deviation. Using Pearson correlative analysis refer to correlation between scores of Zung's self-rating depression scale, Zung's self-rating anxiety scale, pain threshold, pain tolerance and the target-controlled concentration in effect site when sedative depth reached 1 point, 3 point by using OAA/S. There is a statistical correlation when p value is less than 0.05.Results 1. Patients'psychological state (anxiety, depression) was not significantly related with preoperative pain threshold, pain tolerance (all p> 0.05); 2. Preoperative pain threshold was positive related significantly with the target-controlled concentration in effect site when sedative depth was assessed as 1 point, 3 point by using OAA/S, (r1point=0.845, r3point =0.727, all p<0.01), which means the higher the pain threshold, the higher the target-controlled concentration in effect site when sedative depth reached 1 point, 3 point. 3. Pain tolerance was negative related significantly with changes of blood pressure and heart rate after injecting anesthetics after intubation and after skin incision(P<0.05), which means the higher the pain tolerance, the smaller changes of blood pressure and heart rate after intubation and skin incision. 4. There was no significant correlation between preoperative pain threshold and the target-controlled concentration in effect site when sedative depth reached 1 point, 3 point by using OAA/S, (all p>0.05), and changes of blood pressure and heart rate after,after intubation and after skin incision (all p>0.05). 5. There were the linear regression equations : the formula of the target- controlled concentration in effect site when sedative depth was assessed as 3 point: y=0.454x+0.515; when sedative depth was assessed as 1 point: y=0.626x+0.587; (all x=pain tolerance, all y=the target- controlled concentration in effect site). The formula of pain tolerance and difference of mean arterial pressure at baseline and after intubation: y=-8.076x+46.051; after skin incision: y=-8.546x+ 50.290. The formula of pain tolerance and difference of heart rate at baseline and after intubation: y=-8.561x+48.558. after skin incision: y=-11.146x+ 51.095.Conclusion By using the TCI of propofol, preoperative pain tolerance of patients was positive related significantly with the target-controlled concentration in effect site when sedative depth was assessed as 1 point, 3 point by using OAA/S ; Pain tolerance was negative significantly related significantly with changes of blood pressure and heart rate after administration, intubation and skin incision.