| Part I(Basic Study)Objective: To observe the effect of temperature on the density and viscosity of cerebrospinal fluid diluted with 0.5% bupivacaine spinal anesthesia solution(SAS),and to provide some basic theoretical guidance for clinical practice.Method: Twenty women were randomly selected for cesarean delivery under combined spinal epidural anesthesia(CSEA),and 3 ml of cerebrospinal fluid(CSF)was taken from each woman(CSF from 10 women was used to measure density-related indexes,and CSF from 10 women was used to measure viscosity-related indexes).Density-related indexes were measured: 2 ml of CSF was taken to measure the density of CSF in women at 37℃ during labor;1 ml of CSF was mixed with 2 ml of 0.75% bupivacaine to measure the density from 20℃ to 40℃;the viscosity was measured in the same way as density.Results:(1)The density of CSF in term females was 1.00034±0.00008 g/ml(37℃)and the viscosity was 0.6487±0.0110 m Pa·s(37℃).(2)Temperature showed a significant negative correlation with SAS density(r =-0.993),the density of SAS gradually decreased as the temperature increased(when the temperature was less than 35℃ as hyperbaric SAS,isobaric SAS from 35℃ to 37℃,and hypobaric SAS at temperatures greater than 37℃).(3)Temperature showed a significant negative correlation with SAS viscosity(r =-0.924),the viscosity of SAS gradually decreased as the temperature increased,and the viscosity of 0.75% bupivacaine 2ml mixed with CSF 1ml from 35℃ to 40℃ was closest to CSF.Conclusion: The temperature of SAS showed a significant negative correlation with density,and the temperature of SAS showed a significant negative correlation with viscosity,and the density and viscosity of SAS were most similar to that of CSF at 37℃ when the temperature of SAS was at body temperature environment.Part II(Clinical Study)Objective: To observe the effect of ABC groups of SAS on the effect of anesthesia during cesarean section,groups as follows: group A,0.75% bupivacaine(room temperature,22 to 24°C)2 ml + 50% dextrose solution 0.1 ml + CSF 0.9 ml;group B,0.75% bupivacaine(room temperature,22 to 24°C)2 ml + CSF 1 ml;group C,0.75% bupivacaine(body temperature,36 to 37°C)2 ml + CSF 1 ml.Method: 111 maternities with elective cesarean section to be performed under CSEA were collected and randomly divided numerically into three groups of ABC,37 maternities in each group.Primary indicators: incidence of intraoperative hypotension,dose of vasopressors used.Secondary indicators: muscle relaxation satisfaction of the attending surgeon,the time of SAS onset,the earliest site of SAS onset,incidence of adverse events such as intraoperative drowsiness,nausea and vomiting,chest tightness and shortness of breath,pulling and firing,transient neurological symptom,limb phantom,chills,etc.,incidence of intraoperative heart rate >130 beats/min or <60 beats/min.The height of the sensory nerve block plane was recorded at 5 min(T1),10 min(T2),20 min(T3)and at the end of the operation(T4)after anesthesia,intraoperative fluid volume,urine volume and blood loss,and neonatal Apgar score(1 min,5 min).Results:(1)The incidence of hypotension and dopamine use,compared with group A,the incidence of intraoperative hypotension was significantly lower in group B(P < 0.05)and in group C(P < 0.05);compared with group C,the intraoperative dose of dopamine use was greater in group A than in group C(P < 0.05)and in group C than in group B(P < 0.05).(2)Satisfaction with muscle relaxation: compared with group B,the intraoperative myorelaxation satisfaction scores were significantly higher in groups A,group B is smaller than group C(P < 0.05).(3)Height of sensory nerve block: compared with group B,the T1 to T4 sensory nerve block planes were significantly higher in group A than in group B(P < 0.05),and the T1 to T3 block planes were significantly higher in group C than in group B(P < 0.05).(4)Time to onset of SAS and earliest site of action.Compared with group B,the time of SAS onset was(9.1±4.6)s and(12.1±7.3)s in groups A and C than(21.8±6.6)s in group B(P < 0.05),and there was no difference between groups A and C.Compared with group C,the incidence of earliest onset of action in the left hip/left lower extremity was greater in groups A and B than in group C(P < 0.05);the incidence of earliest onset of action in the bilateral hip/bilateral lower extremity was greater in group C than in groups A and B(P < 0.05).(5)Occurrence of intraoperative adverse events and neonatal Apgar score: compared with group B,the incidence of additional intraoperative epidural drugs in groups A and C,4(11.4%)and 6(16.7%),was less than that in group B 13(39.4%),P < 0.05;compared with group B,the incidence of intraoperative pull reflex in group C 4(11.1%)was less than that in group B 12(36.4%),P < 0.05;there was no difference in the occurrence of intraoperative drowsiness,nausea and vomiting,chest tightness and shortness of breath,chills,transient neurological syndrome,limb phantom and abnormal heart rate in the three groups of ABC;There was no difference in neonatal Apgar scores(1 min,5 min).Conclusion: Cerebrospinal fluid diluted body temperature bupivacaine SAS has a lower incidence of hypotension,good intraoperative muscle relaxation,rapid onset of action,and good anesthetic blocking planes,and is more suitable for anesthesia for cesarean section. |
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