Hyperbaric spinal ropivacaine for cesarean delivery: a comparison to hyperbaric bupivacaine.

We evaluated the clinical efficacy and safety of spinal anesthesia with 0.5% hyperbaric ropivacaine compared with 0.5% hyperbaric bupivacaine for elective cesarean delivery. Sixty healthy, full-term parturients were randomly assigned to receive either 12 mg of 0.5% hyperbaric bupivacaine or 18 mg of 0.5% hyperbaric ropivacaine intrathecally. There were no significant differences in demographic or surgical variables or neonatal outcomes between groups. Onset time of sensory block to T10 or to peak level was later in the Ropivacaine group (P < 0.05). The median (range) peak level of analgesia was T3 (T1-5) in the Bupivacaine group and T3 (T1-4) in the Ropivacaine group. Time for sensory block to recede to T10 did not differ between groups. Duration of sensory block was shorter in the Ropivacaine group (188.5 +/- 28.2 min vs 162.5 +/- 20.2 min; P < 0.05). Complete motor block of the lower extremities was obtained in all patients. Ropivacaine also produced a shorter duration of motor blockade than bupivacaine (113.7 +/- 18.6 min vs 158.7 +/- 31.2 min; P < 0.000). The intraoperative quality of anesthesia was excellent and similar in both groups. Side effects did not differ between groups. Eighteen milligrams of 0.5% hyperbaric ropivacaine provided effective spinal anesthesia with shorter duration of sensory and motor block, compared with 12 mg of 0.5% hyperbaric bupivacaine when administered for cesarean delivery Implications: Eighteen milligrams of 0.5% hyperbaric ropivacaine provided effective spinal anesthesia with shorter duration of sensory and motor block, compared with 12mg of 0.5% hyperbaric bupivacaine when administered for cesarean delivery.     

Comparison of hyperbaric and plain bupivacaine with hyperbaric cinchocaine as spinal anaesthetic agents

In a double-blind study, 90 patients (ASA 1 or 2) received spinal anaesthesia with 2 ml hyperbaric cinchocaine 0.5%, 4 ml hyperbaric bupivacaine 0.5% or 4 ml plain bupivacaine 0.5%. All injections were made in the left lateral position, and the patients turned supine immediately. Hyperbaric bupivacaine produced a significantly faster and a higher dermatomal level of bilateral complete sensory blockade than the other solutions (p less than 0.005 for each). The duration of sensory blockade was significantly longer with plain bupivacaine than with either hyperbaric solution (p less than 0.0005). The intensity of sensory blockade was significantly greater with both bupivacaine solutions than with hyperbaric cinchocaine (p less than 0.05). Onset and intensity of motor blockade were similar with all agents, but motor blockade was of significantly shorter duration with hyperbaric bupivacaine than the other agents (p less than 0.0005). Hyperbaric bupivacaine appears to be the best agent for rapid and intense sensory blockade of intermediate duration. Plain bupivacaine is more appropriate if a longer duration of action but a lower height of blockade are required, and has the advantage of less cardiovascular disturbance.     

Unilateral spinal anaesthesia with hyperbaric bupivacaine

Background: The dosage of local anaesthetic and the time the patient must be kept in the lateral decubitus position for a unilateral spinal anaesthesia is not known. The aim of this study was to determine the ideal dosage of hyperbaric bupivacaine and the time required for the lateral decubitus position for a unilateral spinal block. Methods: Ninety patients who were scheduled to receive spinal block for surgery in the lower extremity were randomised into 9 groups (n=10). The spinal block was performed through the L₄–L₅ intervertebral space with the patient in the lateral decubitus position. Patients in groups Ia, Ib, Ic; IIa, IIb, IIc; IIIa, IIIb, IIIc received 1.5 ml of 0.5%, 2 ml of 0.5%, and 2.5 ml of 0.5% hyperbaric bupivacaine solutions, respectively. The patients were turned to the supine position for 5 min after the injection in groups Ia, IIa, IIIa, 10 min after the injection in groups Ib, IIb, IIIb, and 15 min after the injection in groups Ic, IIc, IIIc. The onset and regression of sensory and motor block were checked and compared between the dependent and non-dependent sides in each group. Results: The rate of block progression of the non-dependent side was higher in the groups receiving 2.5 ml 0.5% hyperbaric bupivacaine solution than in the other groups; at the same time the level of block was higher and the duration of block was longer. The incidence of hypotension was 10–20% in these groups. In the 2 ml 0.5% hyperbaric bupivacaine solution groups, a satisfactory block level and duration of anaesthesia for surgery was obtained. The rate of block progression to non-dependent side in the groups receiving 1.5 ml of 0.5% hyperbaric bupivacaine solution was lower than the other groups, but the duration of block was shorter and the level of block was lower than the other groups. Conclusion: For unilateral spinal anaesthesia in lower extremity operations, 2ml 0.5% hyperbaric bupivacaine solution for operations above the knee and 1.5 ml 0.5% hyperbaric bupivacaine solution for operations below the knee and keeping the patients for 10 min in the lateral decubitus position were found to be appropriate.     

Low dose hyperbaric bupivacaine for unilateral spinal anaesthesia

Purpose

To evaluate the effects of hyperbaric bupivacaine concentration in producing unilateral spinal anaesthesia.

Methods

With Ethical Committee approval and written consent, 60 patients undergoing lower limb surgery were placed in the lateral position with the side to be operated on dependent. After durai puncture (25-gauge Whitacre spinal needle), the needle hole was turned toward the dependent side and patients were randomly assigned to receive 8 mg of either 0.5% (Group_05%, n = 30) or 1% (Group_1%, n = 30) hyperbaric bupivacaine. The lateral position was maintained for 15 min, while a blinded observer recorded loss of pinprick sensation and degree of motor block on both sides until two segment regression of sensory level on the dependent side.

Results

At the end of the 15 min lateral position spinal anaesthesia was more frequently unilateral in Group_0.5% (80%) than in Group_1%(53%)(P < 0.05). However, 30 min after patients were turned supine, unilateral spinal anaesthesia decreased to 60% of cases in Group_0.5% and 40% of cases in Group_1%(P = NS). The maximum sensory level on the dependent side [T₁₀(L₁ ? T₂) in Group_0.5% and T₈ (T₁₂ ? T₃) in Group_1%], time to reach it [20 (5–30) min in Group_0.5% and 25 (10–35) min in Group_1%], and time to two segment regression of sensory level [80 (30–135) min in Group_0.5% and 75 (20–135) min in Group_1%] were similar in both groups.

Conclusion

Highly concentrated solutions of hyperbaric bupivacaine are not advantageous in obtaining a unilateral spinal anaesthesia, when a small anaesthetic dose is injected slowly through a Whitacre spinal needle.     

Unilateral spinal anaesthesia for outpatient surgery: a comparison between hyperbaric bupivacaine and bupivacaine–clonidine combination

Backround: Low-dose hyperbaric bupivacaine has been used to produce unilateral spinal anaesthesia for outpatient surgery. Unilateral spinal anaesthesia is associated with reduction of hypotension, faster recovery and increased patient satisfaction. Small doses of clonidine have shown effectiveness in intensifying spinal anaesthesia. We investigated the effect of adding 15 μg of clonidine to 5 mg hyperbaric bupivacaine on unilaterality.
Methods: Sixty patients undergoing outpatient knee arthroscopy were randomly allocated to receive either 1.2 ml (6 mg) of hyperbaric bupivacaine or a 1.2 ml solution containing 1.0 ml (5 mg) hyperbaric bupivacaine, 0.1 ml (75 μg) clonidine and 0.1 ml sterile water. The motor block was assessed by a modified Bromage scale and the sensory block by a pinprick.
Results: There was a significant difference in the spread of anaesthesia between the operated and contralateral sides in both groups. Seventy-seven per cent of the blocks were unilateral in group B and 73% in group B-C. There was no significant difference between the groups, in unilaterality. The motor block was prolonged in group B-C but it did not affect home-readiness. Patients receiving clonidine needed more vasopressors. There was a significant difference in blood pressures between the groups, being lower in group B-C after 1 h 45 min.
Conclusion: Using 5 mg hyperbaric bupivacaine with 15 μg of clonidine, the unilaterality can be achieved and spinal anaesthesia intensified without affecting home-readiness. More vasopressors are needed in the beginning, but after the surgery patients experienced less pain.     

Hyperbaric spinal ropivacaine: a comparison to bupivacaine in volunteers

BACKGROUND: Ropivacaine is a newly introduced local anesthetic that may be a useful alternative to low-dose bupivacaine for outpatient spinal anesthesia. However, its relative potency to bupivacaine and its dose-response characteristics are unknown. This double-blind, randomized, crossover study was designed to determine relative potencies of low-dose hyperbaric spinal ropivacaine and bupivacaine and to assess the suitability of spinal ropivacaine for outpatient anesthesia. METHODS: Eighteen healthy volunteers were randomized into three equal groups to receive one spinal administration with bupivacaine and a second with ropivacaine, of equal-milligram doses (4, 8, or 12 mg) of 0.25% drug with 5% dextrose. The duration of blockade was assessed with (1) pinprick, (2) transcutaneous electrical stimulation, (3) tolerance to high tourniquet, (4) electromyography and isometric force dynamometry, and (5) achievement of discharge criteria. Differences between ropivacaine and bupivacaine were assessed with linear and multiple regression. P < 0.05 was considered significant. RESULTS: Ropivacaine and bupivacaine provided dose-dependent prolongation of sensory and motor block and time until achievement of discharge criteria (R2 ranges from 0.33-0.99; P values from < 0.001 through 0.01). Spinal anesthesia with ropivacaine was significantly different from bupivacaine and was approximately half as potent for all criteria studied. A high incidence of back pain (28%; P = 0.098) was noted after intrathecal ropivacaine was given. CONCLUSION: Ropivacaine is half as potent and in equipotent doses has a similar profile to bupivacaine with a higher incidence of side effects. Low-dose hyperbaric spinal ropivacaine does not appear to offer an advantage over bupivacaine for use in outpatient anesthesia.     

Hyperbaric prilocaine vs. hyperbaric bupivacaine for spinal anaesthesia in women undergoing elective caesarean section: a comparative randomised double-blind study

Hyperbaric bupivacaine spinal anaesthesia remains the gold standard for elective caesarean section, but the resultant clinical effects can be unpredictable. Hyperbaric prilocaine induces shorter motor block but has not previously been studied in the obstetric spinal anaesthesia setting. We aimed to compare duration of motor block after spinal anaesthesia with prilocaine or bupivacaine during elective caesarean section. In this prospective randomised, double-blind study, women with uncomplicated pregnancy undergoing elective caesarean section were eligible for inclusion. Exclusion criteria included: patients aged < 18 years; height < 155 cm or > 175 cm; a desire to breastfeed; or a contra-indication to spinal anaesthesia. Patients were randomly allocated to two groups: the prilocaine group underwent spinal anaesthesia with 60 mg intrathecal prilocaine; and the bupivacaine group received 12.5 mg intrathecal heavy bupivacaine. Both 2.5 µg sufentanil and 100 µg morphine were added to the local anaesthetic agent in both groups. The primary outcome was duration of motor block, which was assessed every 15 min after arriving in the post-anaesthetic care unit. Maternal haemodynamics, APGAR scores, pain scores, patient satisfaction and side-effects were recorded. Fifty patients were included, with 25 randomly allocated to each group. Median (IQR [range]) motor block duration was significantly shorter in the prilocaine group, 158 (125–188 [95–249]) vs. 220 (189–250 [89–302]) min, p < 0.001. Median length of stay in the post-anaesthetic care unit was significantly shorter in the prilocaine group, 135 (120–180 [120–230]) vs. 180 (150–195 [120–240]) min, p = 0.009. There was no difference between groups for: maternal intra-operative hypotension; APGAR score; umbilical cord blood pH; maternal postoperative pain; and patients’ or obstetricians’ satisfaction. We conclude that hyperbaric prilocaine induces a shorter and more reliable motor block than hyperbaric bupivacaine for women with uncomplicated pregnancy undergoing elective caesarean section.     

A prospective randomised trial comparing spinal anaesthesia using hyperbaric cinchocaine with general anaesthesia for lower limb vascular surgery

One hundred and one patients were randomly allocated to have their peripheral vascular surgery performed under general anaesthesia (51 patients) or spinal anaesthesia (50 patients). Intraoperative haemodynamic changes were markedly different between the two groups with a higher incidence of hypotension in the spinal group (72% vs 31%) and a higher incidence of hypertension in the general anaesthesia group (22% vs 0%). Blood loss was significantly less in the spinal group (560, SD 340, ml vs 792, SD 440, ml). Postoperatively three patients from the general anaesthesia group died from causes unrelated to the anaesthesia, and one had a myocardial infarct. Two patients in the spinal group had myocardial infarcts, both had been treated for bradycardia and hypotension intraoperatively, and one died. There was a significantly higher incidence of postoperative chest infection in the general anaesthesia group (33% vs 16%). There was no significant difference between the groups in the incidence of postoperative confusion, or lower limb amputation rate or need for further surgery prior to hospital discharge.     

Spinal anaesthesia using hyperbaric 0.75% vs hyperbaric 1% bupivacaine: a double blind comparison

AIM: The aim of this study was to compare the anesthetic effects, potency and postoperative outcome of 0.75% and 1% concentrations of hyperbaric bupivacaine in selective spinal anesthesia. METHODS: We enrolled 40 patients in a double blind fashion in 2 groups (A= 0.75% bupivacaine; B= 1% bupivacaine). Demographic data were respectively for Groups A and B: age 40.6+/-16 and 67+/-16, weight 74+/-14.4 and 68+/-10.2; sex 10M/10F and 6M/14F; ASA I-II 11/9 and 14/6. All patients received 11.25 mg bupivacaine. In all cases a 27G Whitacre needle was introduced at L1-L2, L2- L3, L3-L4 introduced with a midline approach. Time to onset and offset of sensitive and motor block, dermatomeric extension non invasive blood pressure, heart rate, ephedrine dose, deambulation time, diuresis time and request for supplemental analgesia were recorded. RESULTS: No statistically significant differences between the 2 groups for demographic data were found. Group B revealed a faster onset and a more adequate dermatomeric extension (4.1+/-0.8 min vs 6.5+/-1.2 min). Both concentrations guaranteed good hemodynamic stability. Motor offset times were 115.8+/-145 min and 142+/-4.8 min respectively in groups A and B. Sensitive offset times were 197.5+/-12 min and 168+/-5.2 min respectively in groups A and B. No statistically relevant differences were noticed for intraoperative Bromage, sensitive block or for postoperative motor and sensitive offset time, diuresis time and deambulation time. There are no advantages of 1% hyperbaric bupivacaine over 0.75% for selective spinal anesthesia, while several disadvantages presented shorter duration of postoperative analgesia and higher incidence of headache.     

Hyperbaric spinal levobupivacaine: a comparison to racemic bupivacaine in volunteers.

Levobupivacaine is the isolated S-enantiomer of bupivacaine and may be a favorable alternative to spinal bupivacaine. However, its clinical efficacy relative to bupivacaine and its dose-response characteristics, in spinal anesthesia, must first be known. This double-blinded, randomized, cross-over study was designed to compare the clinical efficacy of hyperbaric levobupivacaine and bupivacaine for spinal anesthesia. Eighteen healthy volunteers were randomized into three equal groups to receive two spinal anesthetics, one with bupivacaine and the other with levobupivacaine, of equal-milligram doses (4, 8, or 12 mg). We assessed blockade quality and duration with pinprick, transcutaneous electrical stimulation, thigh tourniquet, abdominal and quadriceps muscle strength, modified Bromage scale, and time until achievement of discharge criteria. Sensory and motor block were similar between the same doses of levobupivacaine and bupivacaine (P > 0.56 to 0.86). For example, in the 12-mg groups of levobupivacaine versus bupivacaine, mean duration of tolerance to transcutaneous electrical stimulation at T12 was 100 min for both. The duration of motor block at the quadriceps was 71 versus 73 min, and time until achievement of discharge criteria was 164 min for both. Hyperbaric spinal levobupivacaine has equivalent clinical efficacy to racemic bupivacaine for spinal anesthesia in doses from 4 to 12 mg. IMPLICATIONS: Hyperbaric spinal levobupivacaine has equivalent clinical efficacy to hyperbaric spinal bupivacaine over the 4-12-mg ranges.     

Hyperbaric vs. isobaric bupivacaine for spinal anaesthesia for elective caesarean section: a Cochrane systematic review

Both isobaric and hyperbaric bupivacaine have been used for spinal anaesthesia for elective caesarean section, but it is not clear if one is better than the other. The primary objective of this systematic review was to determine the effectiveness and safety of hyperbaric bupivacaine compared with isobaric bupivacaine administered during spinal anaesthesia for elective caesarean section. We included 10 studies with 614 subjects in the analysis. There was no evidence of differences either in the risk of conversion to general anaesthesia, with a relative risk (95%CI) of 0.33 (0.09–1.17) (very low quality of evidence), or in the need for supplemental analgesia, the relative risk (95%CI) being 0.61 (0.26–1.41) (very low quality of evidence). There was also no evidence of a difference in the use of ephedrine, the amount of ephedrine used, nausea and vomiting, or headache. Hyperbaric bupivacaine took less time to reach a sensory block height of T4, with a mean difference (95%CI) of ?1.06 min (?1.80 to ?0.31). Due to the rarity of some outcomes, dose variability, use of adjuvant drugs and spinal technique used, future clinical trials should look into using adequate sample size to investigate the primary outcome of the need for supplemental analgesia.     

A low-dose bupivacaine: a comparison of hyperbaric and hypobaric solutions for unilateral spinal anesthesia

BACKGROUND AND OBJECTIVES: The injection of small doses of local anesthetic solutions through pencil-point directional needles and maintaining the lateral decubitus position for 15 to 30 minutes after the injection have been suggested to facilitate the unilateral distribution of spinal anesthesia. We evaluated the effects of hypobaric and hyperbaric bupivacaine in attempting to achieve unilateral spinal anesthesia for patients undergoing lower limb orthopedic surgery. METHODS: Fifty patients were randomly allocated into 2 groups to receive either 1.5 mL hyperbaric bupivacaine 0.5% (7.5 mg; n = 25) or 4.2 mL hypobaric bupivacaine 0.18% (7.5 mg; n = 25). Drugs were administered at the L3-4 interspace with the patient in the lateral position. Patients remained in this position for 15 minutes before turning supine for the operation. Spinal block was assessed by pinprick and modified Bromage scale on both sides. RESULTS: Unilateral spinal block was observed in 20 patients in the hyperbaric group (80%) and in 19 patients in the hypobaric group (76%) while in the lateral position. However, 15 minutes after patients were turned supine, unilateral spinal anesthesia decreased to 68% of cases in the hyperbaric group and 24% of cases in the hypobaric group (P <.05). The motor block was more intense during the first 5 and 10 minutes (P <.05), but at the end of operation there was no difference between the groups. The hemodynamic changes were similar between the groups. CONCLUSION: As a result, unilateral spinal anesthesia with hyperbaric and hypobaric bupivacaine provided a rapid motor and sensory recovery and good hemodynamic stability, but more unilateral spinal block was achieved in patients in the hyperbaric group when compared with patients in the hypobaric group.     

Hyperbaric bupivacaine affects the doses of midazolam required for sedation after spinal anaesthesia

BACKGROUND AND OBJECTIVE: Patients having spinal anaesthesia with hyperbaric bupivacaine may become sensitive to sedative drugs but no data exists about any dose-related effect of the local anaesthetic on the sedative requirement. We aimed to investigate whether hyperbaric bupivacaine dose in spinal anaesthesia has any effect on midazolam requirements. METHODS: Sixty unpremedicated patients were allocated to three equal groups. Patients in Groups I and II received hyperbaric bupivacaine 0.5% 10 and 17.5 mg respectively for spinal anaesthesia and Group III was a control group without spinal anaesthesia. In Groups I and II, after the evaluation of sensory block, patients received intravenous midazolam 1 mg per 30 s until the Ramsay sedation score reached 3 (drowsy but responsive to command). In Group III, general anaesthesia was induced after sedation score had reached 3 using midazolam. The total dose of midazolam (mg kg(-1)) given to each patient, the level of sensory block and complications were recorded. RESULTS: The level of sensory block was higher in Group II (T7) than Group I (T9) (P < 0.01). The doses of midazolam were 0.063 mg kg(-1) in Group I, 0.065 mg kg(-1) in Group II and 0.101 mg kg(-1) in Group III (P < 0.001). There was no correlation between level of sensory block and dose of midazolam in Group I (r = -0.293, P = 0.21) and Group II (r = 0.204, P = 0.39). CONCLUSIONS: Different doses of hyperbaric bupivacaine for spinal anaesthesia do not affect the midazolam requirements for sedation. However, spinal anaesthesia with hyperbaric bupivacaine with a maximum spread in the middle thoracic dermatomes may be associated with sedative effects and thus a reduced need for further sedation with midazolam.     

Comparison of hyperbaric solutions of bupivacaine and tetracaine during continuous spinal anaesthesia

The aim of this study was to compare two equipotent solutions of hyperbaric bupivacaine and tetracaine in 30 elderly patients undergoing elective hip surgery under continuous spinal anaesthesia. With the patient in the supine position, 2 ml (8 mg) of either hyperbaric solution (density 1.030) were administered in a double-blind and randomized fashion. The median maximum sensory and temperature discrimination levels (T5 and T4) were similar with both solutions. The duration of analgesia was not different (114 +/- 23 min for bupivacaine and 125 +/- 35 min for tetracaine). Thirteen out of fifteen patients receiving bupivacaine and all 15 patients receiving tetracaine had complete motor blockade. The haemodynamic changes and vasopressor requirements were comparable. The plasma catecholamine levels measured at four different times remained unchanged and were not different between the two groups at any time. The authors conclude that, during continuous spinal anaesthesia, equipotent hyperbaric solutions of bupivacaine and tetracaine have similar anaesthetic and haemodynamic effects.     

Home-readiness after spinal anaesthesia with small doses of hyperbaric 0.5% bupivacaine

Fifty-four patients were studied prospectively to evaluate home-readiness after a small dose (1 or 2 ml) of subarachnoid hyperbaric 0.5% bupivacaine. The block regressed significantly earlier in the 1 ml group than in the 2 ml group (p < 0.05). The patients were also able to walk significantly earlier in the 1 ml group (median 161 min and 231 min in the 1 ml and 2 ml groups, respectively) (p < 0.05). However, there were no significant differences between the groups in time of ability to void. We conclude that adequate surgical anaesthesia can be achieved with small doses of hyperbaric bupivacaine used for spinal anaesthesia. Although the sensory and motor block after 1 or 2 ml hyperbaric bupivacaine recovered within a reasonable time for day-case surgery, in some patients recovery of the ability to void was delayed to an undesirable extent.