Observation The Diffusion Of Local Anesthetic In Epidural Space By Imaging Technique In Elder Patients

Objective:The anatomic changes of epidural space with oldpeople,included bone hyperplasia, ligament calcification, degenerative joint,These lead to spinal canal stenosis.High blood pressure, vascularsclerosis,permeability reduce of endorhachis reduce the absorption of localanesthetics.Local anesthetics was easy to widely spread in the epiduralspace,lead to high block plane.The purpose of the research, through theepidural canvity imaging technology,observed the diffusion of localanesthetics in elderly patients's epidural space, investigated the characteristicsof epidural anesthesia medication.Methods：The study protocol was approved by Ethics Committee ofHebei Medical University Third Hospital. Written informed consent wasobtained from each patient after a detailed explanation of the protocol.Sixtypatients (ASA physical status Ⅰ to Ⅲ) were enrolled in this study.All patientsenrolled in this study were divided into two groups on the basis of age:(Ⅰ) the elderlygroup (65~74yr of age,13female and15male patients)(Ⅱ)the young group (25~34yr of age,12female and17male patients).They wereplaced in the left lateral position on a horizontal operating table. Epiduralpuncture was performed aseptically by an attending anesthetist at the L2-L3level of the lumbar intervertebral space using a reusable16G winged Tuohyneedle by a paramedian approach with the loss of resistance(LOR) to air using0.3ml.On entering the epidural space,the bevel of the needle was pointedcephalad.The epidural catheter was advanced3cm in the cephalad directioninto the epidural space.After confirming negative aspiration of cerebrospinalfluid and blood,5ml of2%chloroprocaine with3ml Omnipaque was injectedat the rate of5ml.min-1(5%chloroprocaine was diluted with sterilizationinjection water into10ml. Take2ml of (5%chloroprocaine and3ml of iohexol(nonionic300mgI/ml) made up with5ml of2%chloroprocaine) in theleft lateral position. Five minutes after injection of the anesthetic,the spreadwas studied by taking X-rays after both injections in the left lateral position.The spread of contrast medium were recorded by epidurograms after5mlinjection of2%chloroprocaine through the epidural catheter. Five minutesafter the anesthetics injection,assessment of the spread of hypesthesia to coldand pain on both sides of the body according to a dermatomal chart,usingcotton soaked in rubbing alcohol and pinprick,was performed by an individualblinded to determine the sensory blockade.The extent of the hypesthesia wascalculated as the average dermatome of both side.Results:1No statistically significant differences were found between the elderlygroup and the young group on sex, weight, height(P>0.05).2The total radiographic length of2%chloroprocaine in epidural canvitywere13.0±2.8cm in the elderly group. The total radiographic length of2%chloroprocaine were9.0±2.1cm in the young group.The total radiographiclength of2%chloroprocaine was significantly greater in the elderly groupthan in the young group.(P<0.05).3The spread segments of2%chloroprocaine in epidural canvity were5.3±1.2segments in the elderly group.The spread segments of2%chloroprocaine in epidural canvity were3.3±0.8segments in the younggroup.The spread segments of2%chloroprocaine was significantly greater inthe elderly group than in the young group.(P<0.05).4The dose of one spinal segment were1.0±0.2ml in the elderly group,The dose of one spinal segment were1.6±0.4ml in the young group. The doseof one spinal segment was statistically lesser in the elderly group than in theyoung group (P<0.05).5In the elderly group, the number of spinal segments with hypesthesiafor prinprick were6.6±0.7dermatomes, the number of spinal segments withhypesthesia for coldness were6.3±0.7dermatomes. In the young group, thenumber of spinal segments with hypesthesia for prinprick were3.3±0.4 dermatomes, the number of spinal segments with hypesthesia for coldnesswere2.8±0.3dermatomes. the number of spinal segments with hypesthesia forprinprick and the number of spinal segments with hypesthesia for coldnesswas significantly greater in the elderly group than in the younggroup(p<0.05).6In the elderly group, the number of spinal segments with hypesthesiafor prinprick were6.6±0.7dermatomes, the number of spinal segments withhypesthesia for coldness were6.3±0.7dermatomes.The spread segments of2%chloroprocaine in epidural canvity were5.3±1.2segments.There were nosignificant differences between the number of spinal segments withhypesthesia for coldness and prinprick (p>0.05). There were no significantdifferences between the number of spinal segments with hypesthesia forprinprick and the spread segments of2%chloroprocaine(p>0.05). There wereno significant differences between the number of spinal segments withhypesthesia for coldness and the spread segments of2%chloroprocaine(p>0.05).7In the young group, the number of spinal segments with hypesthesiafor prinprick were2.8±0.3dermatomes, the number of spinal segments withhypesthesia for coldness were3.3±0.4dermatomes, the spread segmentsofof2%chloroprocaine in epidural canvity were3.3±0.2segments. There wereno significant differences between the number of spinal segments withhypesthesia for coldness and the spread segments of2%chloroprocaine(p>0.05). There were no significant differences between the number of spinalsegments with hypesthesia for prinprick and the spread segments of2%chloroprocaine (p>0.05). The number of spinal segments with hypesthesiafor coldness was significantly wider than the number of spinal segments withhypesthesia for prinprick in the young group(p<0.05).Conclusion:1The spread of local anesthetics in epidural space was significantlygreater in the elderly group than in the young group with the same volum ofanesthetic solution,the dosage of epidural anesthesia should reduce in the elderly patients.2The dose of one spinal segment were1.0±0.2ml in the elderly patientsgroup, The dose of one spinal segment were1.6±0.4ml in the young paients.