Epidural anesthesia with bupivacaine: effects of age on neural blockade and pharmacokinetics

Effects of aging after epidural administration of 0.5% bupivacaine without epinephrine were studied in two groups of patients, between 20 and 55 yr old and older than 55 yr, respectively. All patients received 95 mg bupivacaine HCl. The onset of analgesia in caudad segments decreased with age and the upper level of analgesia increased with age. Effects of age on duration of anesthesia could not be demonstrated. The total plasma clearance of bupivacaine decreased and the terminal half-life increased with age. Age had no effect on the peak plasma concentrations and time to peak concentrations.     

Epidural anesthesia with 0.5% bupivacaine: influence of age on sensory and motor blockade

To determine the influence of age on epidural blockade, 10 elderly male patients (mean age, 73 yr) and 11 young male volunteers (mean age, 25 yr) received epidural anesthesia with 20 mL of 0.5% bupivacaine with epinephrine at the L2-3 interspace. Median cephalad analgesia level (pinprick) was T-4 in the elderly and T-10 in the young subjects (P less than 0.01). The duration of analgesia at the L-1 to S-3 segments was about 60 min shorter in the older patients than in the young volunteers (P less than 0.05). Motor blockade was evaluated quantitatively by isometric muscle force measurements in the lower extremities and by electromyographic recordings from the abdominal and quadriceps muscles. Motor blockade in the lower extremities was also assessed qualitatively by the Bromage scale. The intensity of motor blockade was not influenced by age. The mean duration of maximal motor blockade of the lower abdominal muscles was 69 min in elderly patients and 140 min in young subjects (P less than 0.05). The corresponding mean duration in the lower extremities was approximately 1.5 h in the older patients and 3 h in the young subjects (P less than 0.01). The elderly patients could be mobilized 2 h earlier than the young volunteers. Duration of Bromage grade 1 was about 1.5 h shorter in the elderly than in the young subjects (P less than 0.01). Not until 1.5-2 h after attainment of Bromage grade 0 was the muscle force in the lower extremities restored to 90% of baseline value. The authors conclude that cephalad spread was more extensive and duration of epidural blockade was shorter in elderly patients versus younger volunteers.     

The effects of age on neural blockade and hemodynamic changes after epidural anesthesia with ropivacaine

We studied the influence of age on the neural blockade and hemodynamic changes after the epidural administration of ropivacaine 1.0% in patients undergoing orthopedic, urological, gynecological, or lower abdominal surgery. Fifty-four patients were enrolled in one of three age groups (Group 1: 18-40 yr; Group 2: 41-60 yr; Group 3: > or=61 yr). After a test dose of 3 mL of prilocaine 1.0% with epinephrine 5 microg/mL, 15 mL of ropivacaine 1.0% was administered epidurally. The level of analgesia and degree of motor blockade were assessed, and hemodynamic variables were recorded at standardized intervals. The upper level of analgesia differed among all groups (medians: Group 1: T8; Group 2: T6; Group 3: T4). Motor blockade was more intense in the oldest compared with the youngest age group. The incidence of bradycardia and hypotension and the maximal decrease in mean arterial blood pressure during the first hour after the epidural injection (median of Group 1: 11 mm Hg; Group 2: 16 mm Hg; Group 3: 29 mm Hg) were more frequent in the oldest age group. We conclude that age influences the clinical profile of ropivacaine 1.0%. The hemodynamic effects in older patients may be caused by the high thoracic spread of analgesia, although a diminished hemodynamic homeostasis may contribute. IMPLICATIONS: Analgesia levels after the epidural administration of 15 mL of ropivacaine 1.0% increase with increasing age. This is associated with an increased incidence of hypotension in the elderly, although an effect of age on the hemodynamic homeostasis may have contributed. It appears that epidural doses should be adjusted for elderly patients.     

Spinal anesthesia with hyperbaric lidocaine and bupivacaine: effects of epinephrine on the plasma concentration profiles

The effects of epinephrine on the plasma concentration profiles and some derived pharmacokinetic parameters were studied after subarachnoid injection of hyperbaric lidocaine and bupivacaine solutions. Addition of epinephrine to the local anesthetic solution reduced the mean peak plasma concentration of lidocaine from 526 to 376 ng/ml, but did not significantly reduce the mean peak plasma concentration of bupivacaine (70 vs 56 ng/ml). Epinephrine did not affect the times at which the peak concentrations were reached, the terminal half-lives, or the total plasma clearances. The observed effects of epinephrine on the peak plasma concentrations are consistent with the vascular activity of lidocaine and bupivacaine, respectively.     

Spinal-induced hypotension in elderly patients with hip fracture. A comparison of glucose-free bupivacaine with glucose-free bupivacaine and fentanyl

Intraoperative hypotension is a common and potentially deleterious event in elderly patients undergoing spinal anaesthesia for repair of hip fractures. The synergism between intrathecal opioids and local anaesthetics may allow a reduction in the dose of local anaesthetic and cause less sympathetic block and hypotension, while still maintaining adequate anaesthesia. We studied 40 elderly patients having either an insertion of a dynamic hip screw or a hemiarthroplasty and compared 9.0 mg glucose-free bupivacaine with added fentanyl 20 microg (group BF) with 11.0 m glucose-free bupivacaine alone (group B). Hypotension was defined as a fall in systolic blood pressure to less than 75% baseline or less than 90 mmHg. The incidence and frequency of hypotension in group BF were less than in group B. Similarly, falls in systolic, diastolic and mean blood pressures were all less in group BF than in group B. However, there were four failed blocks in group BF and one in group B.     

Spinal anesthesia with isobaric bupivacaine for percutaneous nephro-ureterolithotomy

The duration of analgesia and the cardiovascular changes during anesthesia of spinal blockade with isobaric bupivacaine were examined in 36 patients between 21 and 75 years old undergoing percutaneous nephro-ureterolithotomy. Injection of 0.25% or 0.5% bupivacaine 3.0-4.0 ml through the L3-4 or L2-3 intervertebral space in the horizontal posture resulted in spread of hypalgesia to T6 in 30 patients and of analgesia to T6 in about a half of the patients. In six patients, another intrathecal injection of 2 ml of bupivacaine was performed because their analgesia level had been under T8. Although the operation took 32-141 min. (mean 77.7 +/- 27.5 min.), there was no case requiring exigent exchanging anesthesia for general anesthesia. The frequencies of the hypotension, bradycardia and nausea in spinal blockade with isobaric bupivacaine were not so different from those of the previous epidural anesthesia in 29 patients undergoing the same operation. Most of the cardiovascular changes in the spinal blockade with isobaric bupivacaine happened within 20-30 min. after intrathecal injection of bupivacaine. Spinal anesthesia with isobaric bupivacaine proved satisfactory for percutaneous nephro-ureterolithotomy.     

Spinal anesthesia with plain bupivacaine 0.5%: regression of sensory and motor blockade with different temperatures of the anesthetic solution

Onset (defined as the time between injection and achievement of the highest level of sensory blockade), duration, and regression of sensory and motor blockade after the intrathecal administration of 3 mL plain bupivacaine 0.5%, previously equilibrated to either 37 degrees C or 20 degrees C, were studied in two groups of 20 patients. In patients receiving the solution equilibrated to 37 degrees C, the maximum level of sensory blockade was significantly higher (T 4.6 vs T 7.5), variability was smaller (SEM 0.33 vs 0.58), and duration of the sensory level of blockade at or above T 6, T 8, and T 10 was significantly longer (56 min vs 20 min, 101 min vs 59 min, and 131 min vs 77 min, respectively). There were no significant differences with regard to onset of sensory and motor blockade or either the time needed both for the sensory level of blockade to regress two segments from its highest level and to the first lumbar segment, or the duration of complete motor blockade of the lower limbs. It is concluded that the intrathecal administration of a bupivacaine solution previously equilibrated to 37 degrees C as compared with a solution injected at room temperature results in a higher, more predictable maximum sensory level of blockade with longer duration at or above T 6, T 8, and T 10.     

Spinal anesthesia with isobaric 0.5% bupivacaine for lower limb surgery: effects of different volumes

BACKGROUND: The effects of different volumes (2.4, 2.6, 2.8 and 3.0 ml) of isobaric 0.5% bupivacaine used for spinal anesthesia were compared in 206 patients scheduled for lower limb surgery. METHODS: The spinal anesthesia was performed with the patients in the lateral position and the isobaric 0.5% bupivacaine was injected intrathecally at the L3-4 interspace. RESULTS: The time to maximum cephalad spread of anesthesia (loss of cold sensation) varied between 25 and 40 min. A significant difference was found in cephalad spread between 2.4 ml group and 3.0 ml group (T11 vs T7), and between 2.6 ml group and 3.0 ml group (T11 vs T7). Severe hypotension did not occur during the study. CONCLUSIONS: Spinal anesthesia with 2.8 ml of isobaric 0.5% bupivacaine proved satisfactory for lower limb surgery.     

重比重布比卡因蛛网膜下腔阻滞用于高龄患者人工髋关节置换手术

目的　介绍重比重布比卡因脊麻用于高龄患者人工髋关节置换手术的体会。方法　 19例ASAⅡ～Ⅲ级 80岁以上的高龄患者 ,按 0 12～ 0 15mg/kg于L3～ 4间隙行重比重布比卡因脊麻 ,记录术中BP、HR、SpO2 、呼吸、升压药使用情况及并发症。结果　 19例脊麻全部成功 ,阻滞平面T8～ 10 以下 ,面罩吸氧下SpO2 均>97% ,除 3例SBP下降超过术前 3 99kPa需处理外 ,余例BP、HR均较平稳 ,术中、术后未见其他并发症。结论　只要控制药物用量、管理得当 ,脊麻用于高龄患者髋部手术是安全可行的。     

碱化丁哌卡因硬膜外阻滞的药效学与药代动力学观察

目的:观察碱化与非碱化丁哌卡因硬膜外阻滞的药效学与药动学。方法:选择ASA Ⅰ～Ⅱ级行下肢手术患者60例。随机分成两组,每组30例。均用0.75％丁哌卡因1.5mg/kg行硬膜外阻滞,对比观察麻醉效果,并对碱化组中的8例,对照组中的6例作药代动力学研究。结果:与对照组比,碱化组起效时间和阻滞完善时间短,镇痛时间长,感觉神经阻滞节段数多(P<0.01)。两组药代动力学指标无显著差异(P>0.05)。结论:碱化丁哌卡因用于硬膜外阻滞,其效果优于非碱化丁哌卡因。     

The influence of baricity on differential blockade with 0.5% bupivacaine spinal anesthesia

We evaluated the influence of baricity on differential blockade during spinal anesthesia using isobaric or hyperbaric 0.5% bupivacaine. Forty ASA-PS I-II patients scheduled for elective surgery (orthopedic, lower abdominal and urologic) were divided into two groups; group H, using hyperbaric 0.5% bupivacaine, and group I, using isobaric 0.5% bupivacaine. Spinal anesthesia was performed in lateral decubitus position, using a 25-gauge Quincke needle at L2-3 interspace, and 0.5% bupivacaine 2.0 ml was injected for 10 seconds. Patients were turned to supine position soon after the spinal anesthesia and the block levels were examined every 5 min for 30 min. Sympathetic blockade was detected by observer's hand, the loss of cold sensation by alcohol sponge and the loss of pain sensation by pinprick. Complete motor blockade was detected by modified Bromage scale. Significant higher sensory blockade and large number of complete motor block were observed in group H. Differential blockade between sympathetic and sensory was significant and lasted 30 min in group I, but lasted only 15 min in group H.     

Spinal anesthesia with hypobaric bupivacaine for knee arthroscopies: effect of posture on motor block

BACKGROUND AND OBJECTIVES: The clinical impact of patient positioning on motor block during unilateral spinal anesthesia was the focus of our study. It was assumed that a 45 degrees rotation toward the prone position would minimize blocking the ventral motor roots compared with using the conventional lateral decubitus position. METHODS: Spinal anesthesia with 3.4 mL of hypobaric 0.18% bupivacaine via a 27-gauge Whitacre needle was administered to 70 patients undergoing knee arthroscopy. The patients were kept either in a lateral decubitus position (group I) or rotated approximately 45 degrees toward the prone position (group II). No prophylactic vasopressors or infusions were used. The intensity of motor block (modified Bromage scale) was assessed for both the operative and the contralateral side. RESULTS: The patients in group I had a slightly more pronounced motor block, but statistical significance could be shown only 20 minutes following the block. There was no statistical difference between the groups in the need of additional analgesics during the operation. None of the patients needed general anesthesia. The hemodynamics were stable and none of the patients developed postspinal headache or backache. CONCLUSIONS: The position of the patient affects the spread of the spinal anesthesia when clearly hypobaric agents are used. However, this small modification in positioning of the patient did not lead to a clinically meaningful difference in the spread of the motor block.     

Spinal anesthesia in children: comparative study of hyperbaric bupivacaine with or without clonidine

OBJECTIVE: To evaluate the effect of intrathecal clonidine in children. STUDY DESIGN: A prospective randomised study. PATIENTS AND METHODS: 45 children, 6 to 15 years old, were randomised in two groups; receiving either 0.5% hyperbaric bupivacaine or 0.5% hyperbaric bupivacaine added to clonidine 2 micrograms.kg-1. We assessed quality and length of motor and sensory blocks and side effects of clonidine: hypotension, bradycardia and sedation. RESULTS: Clonidine was associated with prolongation of motor block. 190 +/- 42 min vs 150 +/- 35 min (p < 0.01), but the difference was not significant. Postoperative analgesia was longer in clonidine group, 490 +/- 35 min vs 200 +/- 50 min (mean +/- SD), p < 0.001. Clonidine was associated with higher incidence of hypotension 54 vs 36% and bradycardia 30 vs 0%. CONCLUSION: These data suggest that intrathecal clonidine 2 micrograms.kg-1 is associated with extending duration of postoperative analgesia but with moderate side effects.     

Effects of age on blood pressure, heart rate, and sensory blockade by spinal anesthesia with plain 0.5% bupivacaine]

To discover the influence of age on spinal blockade with plain bupivacaine, 23 patients were administered a subarachnoid injection of approximately 4.0 ml of 0.5% bupivacaine. The patients were divided into two groups. One group consists of patients with ages under 65 years (younger group, n = 13), and the other group consists of patients older than 65 years (elder group, n = 10). The following results were obtained. The time to onset of anesthetic effects (pinprick discrimination, temperature discrimination, and light touch discrimination) decreased with age. At 180 min after the administration, spinal blockade level did not have a significant difference. The degree of the decrease of systolic arterial pressure was greater in the elder group than in the younger group. However, the degree of the decrease of heart rate was greater in the elder group than in the younger group.     

Spinal anesthesia with bupivacaine. Comparative study of 2 hyperbaric and isobaric solutions

This study compared two isobaric and hyperbaric solutions of 0.4% bupivacaine used for carrying out spinal anaesthesia in 264 patients more than 70 years old undergoing comparable surgical procedures. With the hyperbaric solution, the mean time of onset of analgesia was shorter: 8.4 +/- 4 min (11.5 +/- 5.1 min with the isobaric solution), the level of analgesia higher by two dermatomes and the mean duration of analgesia longer: 147.3 +/- 24.8 min (121.1 +/- 24.8 min with the isobaric solution). Blood pressure fell more often with the hyperbaric solution. The motor block, assessed by the inability to move the legs and abdominal wall paralysis, was more complete with the hyperbaric solution. Lastly, there were less failures: 3.4% with hyperbaric solution and 12.1% with isobaric solution.