Bupivacaine Plain Solution Research Articles

Density of spinal anaesthetic solutions of bupivacaine, levobupivacaine, and ropivacaine with and without dextrose

Spread of intrathecal local anaesthetics is determined principally by baricity and position of the patient. Hypobaric solutions of bupivacaine are characterized by an unpredictable spread of sensory block whereas addition of dextrose 80 g ml(-1) provides a predictable spread but to high thoracic levels. In contrast, dextrose concentrations between 8 and 30 g ml(-1) have shown reliable and consistent spread for surgery. Hence, the aim of this study was to determine the density of bupivacaine, levobupivacaine, and ropivacaine with and without dextrose at both 23 and 37 degrees C before embarking on clinical studies. Density (g ml(-1)) was measured using the method of mechanical oscillation resonance, accurate to five decimal places on 1250 samples. 500 density measurements were performed in a randomized, blind fashion at 23 and 37 degrees C on 10 plain solutions of bupivacaine (2.5, 5, and 7.5 g ml(-1)) levobupivacaine (2.5, 5, and 7.5 g ml(-1)) and ropivacaine (2, 5, 7.5, and 10 g ml(-1)). Following this, 750 density measurements were taken at 23 and 37 degrees C on the 5 g ml(-1) solutions of bupivacaine, levobupivacaine, and ropivacaine with added dextrose (10, 20, 30, 50, and 80 g ml(-1)). There was a linear relationship between density and dextrose concentration for all three local anaesthetics (R(2)=0.99) at 23 and 37 degrees C. The mean density of levobupivacaine 5 g ml(-1) was significantly greater than the densities of bupivacaine 5 g ml(-1) and ropivacaine 5 g ml(-1) after adjusting for dextrose concentration using analysis of covariance. This difference existed both at 23 and 37 degrees C. The mean (sd) density of levobupivacaine 7.5 g ml(-1) was 1.00056 (0.00003) g ml(-1), the lower 0.5% percentile (1.00047 g ml(-1)) lying above the upper limit of hypobaricity for all patient groups. The density of local anaesthetics decreases with increasing temperature and increases in a linear fashion with the addition of dextrose. Levobupivacaine 5 g ml(-1) has a significantly higher density compared with bupivacaine 5 g ml(-1) and ropivacaine 5 g ml(-1) at 23 and 37 degrees C both with and without dextrose. Levobupivacaine 7.5 g ml(-1) is an isobaric solution within all patient groups at 37 degrees C [corrected]

Plasma concentrations of bupivacaine following single needle lumbar sympathectomy using two volumes of 0.25% bupivacaine plain solution

Plasma concentrations of bupivacaine following single needle lumbar sympathectomy using two volumes of 0.25% bupivacaine plain solution

Local analgesic and vascular effects of intradermal ropivacaine and bupivacaine in various concentrations with and without addition of adrenaline in man

Ropivacaine, a new long-acting amino-amide local anaesthetic agent, and bupivacaine, in various concentrations with or without addition of adrenaline, were tested in a randomized, double-blind study using intradermal wheals. Ten non-smoking, healthy, young male volunteers participated. In series I plain solutions of ropivacaine (0.25%, 0.5%, 0.75% and 1%) and bupivacaine (0.25%, 0.5% and 0.75%) were injected intradermally and in series II the same concentrations, with the addition of adrenaline 5 ug.ml-1 (1:200,000), were used. The same volunteers took part in both series, with an interval of at least three weeks between the experiments. Saline was included as control in both series. Pin-pricking was used to assess the dermal analgesia. Plain solutions of ropivacaine produced significantly longer durations of dermal analgesia than did plain solutions of bupivacaine, in all tested concentrations. A significant increase in duration was seen for both local anaesthetics when adding adrenaline. Local vascular effects at the injected areas were determined by visual inspection (nil, pink, pale). Local blanching (pale) was significantly more frequent for plain solutions of ropivacaine, in all tested concentrations. Local redness (pink) was significantly more frequent with plain bupivacaine, in a dose-dependent relation. An initial redness was frequently observed for both local anaesthetics containing adrenaline, followed by blanching at most sites.

Effect of Increasing Amounts of Epinephrine during Isobaric Bupivacaine Spinal Anesthesia in Elderly Patients

The effects of adding epinephrine to isobaric bupivacaine spinal anesthesia were investigated in 96 ASA class II-III patients aged 75 yr or more scheduled for lower extremity surgery. The subjects were randomly allocated into six groups. All patients received 15 mg bupivacaine plain solution in 4 ml, in the horizontal position. Patients in group 1 received bupivacaine plus 1 ml normal saline; patients in other groups received bupivacaine plus increasing dosages of epinephrine: 0.1 mg (group 2), 0.2 mg (group 3), 0.3 mg (group 4), 0.4 mg (group 5), 0.5 mg (group 6). The segmental level of sensory loss was tested using forceps. The time required for maximal spread of the sensory blockade was significantly 50% greater in group 5 than in group 1. No difference was observed, however, between mean highest levels. Addition of 0.2 mg epinephrine prolonged by a significant 25% regression time to L-2 level. Addition of 0.3 and 0.4 mg epinephrine significantly prolonged two-segment regression time by 36 and 53%, respectively, and regression to L-2 level by 29 and 44%, respectively. Addition of 0.5 mg epinephrine did not result in further prolongation of anesthesia. Motor blockade was also increased by addition of epinephrine. It is concluded that addition of 0.3 mg epinephrine may be useful to increase duration of isobaric bupivacaine spinal anesthesia.

EXTRADURAL ANALGESIA: THE INFLUENCE OF VOLUME AND CONCENTRATION OF BUPIVACAINE ON THE MODE OF DELIVERY, ANALGESIC EFFICACY AND MOTOR BLOCK

Five hundred and seventeen women in labour receiving extradural analgesia, using bupivacaine plain solution, were randomly allocated to one of three groups. Group A received 6-8ml of 0.5% solution, group B 10-14ml of 0.25% solution, and group C 6-8 ml of 0.25% solution. Spontaneous delivery occurred in 31.7% of patients in group A, 38.7% in group B and 53% in group C (P less than 0.001). The percentage of rotational forceps, ventouse and Caesarean section deliveries was similar in the three groups. Analgesia was most effective in group A, and at least in group C, both during labour and at delivery, although assessment by linear analogue score suggested that the differences between the three groups were slight. Motor block was most frequent and rapidly progressive in groups A, but was progressive in all groups, and after five or more top-up injections, was similar in the three groups. Difficulties with micturition following delivery were significantly more common in group A.