Blood level of marcaine (LAC-43) in axillary plexus blocks, intercostal nerve blocks and epidural anaesthesia

A new axillary approach for continuous brachial plexus block. A clinical and anatomic study

Catheter insertion in the neurovascular space by axillary approach allows a continuous brachial plexus block and/or postoperative analgesia. We developed a perivenous technique whereby the approach to the neurovascular sheath is guided under fluoroscopy by a preopacified axillary vein. A randomized study compared this technique to the technique of Selander in ASA grade I-II patients scheduled for surgery or painful physiotherapy of the hand. The study was performed in 36 patients randomly divided into two groups. In Group 1 (n = 18), the catheter was placed according to the technique described by Selander. In Group 2 (n = 18), the catheter was placed using our perivenous technique. A complete block was obtained in all the patients of Group 2 vs only 50% of the patients in Group 1 (P < 0.05). In Group 1 a partial block was observed in 17%, with failure in 33% of the patients. There was no difference in the two groups regarding the time required to perform either technique, the duration of the complete block, the pain score, or the amount of continuously administrated bupivacaine during the first 48 h postoperatively. The plasma concentrations of total bupivacaine (high-performance liquid chromatography) were low in successful blocks, with no differences in the two groups; the median value was 0.68 microgram/mL (95% confidence interval: 0.62-0.89). The concentrations were higher (P < 0.01) in failed blocks; the median value was 1.69 micrograms/mL (95% confidence interval: 0.58-2.8). A complementary anatomic study of three arms from fresh cadavers allowed verification of the correct localization of the Teflon cannula and flexible catheter, as well as homogeneous diffusion of the methylene blue inside the brachial plexus. The perivenous technique for continuous axillary brachial plexus block may improve the success rate due to its radiologic and accurate location of the neurovascular sheath.

Postoperative analgesia with intrapleural administration of bupivacaine-adrenaline

Twenty-one patients who underwent elective cholecystectomy were studied with regard to the effect of intrapleural administration of bupivacaine-adrenaline solution on postoperative pain and ventilatory capacity. Administration of 10 or 20 ml of 2.5 mg/ml or 5 mg/ml bupivacaine solution resulted in complete analgesia in 143 of 159 administrations. Most patients experienced the maximal pain-relieving effect within 1-2 min and analgesia persisted as a rule for 3-5 h. Forced vital capacity and forced expiratory volume in 1 s increased after intrapleural analgesia on average by 56% and 46%, respectively, on the first postoperative day and by 35% and 51%, respectively, on the second day. There was no significant difference in the analgesic effect or in the effect on the ventilatory capacity between the 2.5 mg/ml or the 5 mg/ml solution, in either the 10 ml or the 20 ml dose. Placebo (NaCl) given intrapleurally had no effect on pain or on the ventilatory capacity. The plasma concentration of bupivacaine after intrapleural administration showed a wide interindividual variation, with considerably higher average values when the 5 mg/ml solution had been used than for the 2.5 mg/ml solution. Although no toxic effects were noted, a 2.5 mg/ml solution, which can be given in an initial dose of 20 ml and top-up doses of 10 ml at 3-6 h intervals, is recommended. In four patients minor pneumothorax developed when the catheter was introduced. The pneumothorax was easily evacuated, but underlines the need for great care when introducing the catheter.

Plasma bupivacaine concentrations after axillary block in children

Venous plasma concentrations of bupivacaine were measured in children following axillary brachial plexus block with either 2 mg/kg (n = 21) or 3 mg/kg (n = 20) of bupivacaine. Absorption was very rapid with a mean time to peak concentrations of 0.37 hours for both doses. Mean peak plasma concentration was 1.35 mg/l after the 2 mg/kg dose and 1.84 mg/kg after the 3 mg/kg dose. Even after a 30% allowance for anticipated higher arterial concentrations, the plasma levels found in the present study were well below those at which toxicity is considered likely (greater than 4 mg/l).

Plasma bupivacaine concentrations following lumbar epidural anaesthesia in children

Plasma levels of bupivacaine were measured following lumbar epidural administration of 3 mg/kg of 0.5% plain solution in sixteen children. The peak levels were generally between 1.0 and 2 micrograms/ml, the highest being 2.9 micrograms/ml. No manifestations of toxicity were observed. There was a significant positive correlation between peak plasma levels and increasing age.

Respiratory performance after upper abdominal surgery. A comparison of pain relief with intercostal blocks and centrally acting analgesics

The respiratory capacity was studied during the first 2 days postoperatively in 94 patients, aged 19 to 75 years and undergoing surgery through an upper abdominal incision. Postoperative pain relief was randomly administered, either by intercostal block (i.c.b.) and centrally acting analgesics on demand, or by centrally acting analgesics alone. Respiratory studies comprising forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow rate (PEF) and analysis of arterial blood gases were made. Bilateral i.c.b. given after surgery performed through a midline incision did not improve the respiratory function, whereas unilateral i.c.b. after surgery through a subcostal incision had positive effects. Thus postoperative i.c.b. following cholecystectomy performed through a subcostal incision resulted in higher FVC, FEV1 and PEF values than without i.c.b. at least during the time of effective nerve block. I.c.b. after subcostal incision also improved arterial oxygen tension. The patients undergoing cholecystectomy and receiving a second i.c.b. 8 h after the first one had better respiratory function than the patients without any block during the first 2 days postoperatively.

Factors influencing the respiratory capacity after upper abdominal surgery

The analgesic requirement and some factors influencing the respiratory capacity after upper abdominal surgery were studied during the first 2 days postoperatively in 417 patients, aged 17 to 84 years, undergoing surgery in the upper part of the abdomen. The operations were cholecystectomy or choledocholithotomy through a subcostal incision, partial gastric resection, repair of a diaphragmatic hernia or vagotomy through a midline incision. Pain relief was achieved in a random order either by intercostal block (i.c.b.) and centrally acting analgesics on demand, or by centrally acting analgesics alone. The analgesic demand was recorded, and the respiratory capacity was monitored by the peak expiratory flow rate (PEF). A smaller analgesic requirement and a smaller change in PEF were found after cholecystectomy than after any other kind of surgery. The demand for analgesics was age-dependent, and patients under 60 years of age demanded more than those aged 60 years and older. Bilateral i.c.b. given after surgery through a midline incision had few advantages, but unilateral i.c.b. following cholecystectomy and choledocholithotomy with a subcostal incision had positive effects. Thus it decreased the demand for centrally acting analgesics and resulted in higher PEF values than without i.c.b. for cholecystectomy during the period of effective nerve block and for choledocholithotomy for 2 whole days postoperatively. Smokers seemed to benefit from i.c.b. for 2 postoperative days. The reduction of PEF after cholecystectomy also seemed to be related to the duration of treatment with centrally acting analgesics.

Splanchnic turn-over of some energy metabolites and acid-base balance during intravenous infusion of lidocaine, bupivacaine or etidocaine

The splanchnic turn-over of energy metabolites in circulating blood has been studied in four groups of young, healthy volunteers, receiving intravenous infusions of physiological saline (n = 5), lidocaine 4 mg/min (n = 7), bupivacaine 2 mg/min (n = 7) and etidocaine 2 mg/min (n = 8). The results showed that the local anaesthetic agents increased the splanchnic blood flow and oxygen consumption, the uptake of glycerol and lactate, and the release of 3-hydroxybutyrate. These effects are adrenaline-like but cannot be explained by one single mechanism involving increased activity of the sympathetic nervous system. Only a minor part of the increased oxygen uptake could be attributed to the energy cost of drug metabolism.

Bupivacaine (Marcaine): an evaluation of its tissue and systemic toxicity in humans

In countries other than the U.S.A., dosages of bupivacaine have been limited to 100 mg without epinephrine and 150 mg with epinephrine. A review of 7,688 regional block procedures employing bupivacaine in concentrations of 0.25, 0.5, and 0.75%, and in dosages as high as 600 mg, indicated that such stringent restrictions: (1) are unwarranted, (2) make comparisons with other local anesthetic agents difficult, and (3) are in need of revision.

The control of postoperative wound pain with the use of bupivacaine injections

In a study of 50 operative cases 0.5% bupivacaine hydrochloride solution was injected in the area of the subcostal nerves at the time of closure of the wound except in 2 with previously noted infection. In the latter 2 cases the solution was injected when the wound was opened. No untoward results were noted from these injections and a definite decrease in the use of analgesics was required. In addition, there is preliminary evidence that peristalsis and flatus occur much earlier in cases in which the solution was used compared to a control group. Respiration was enhanced, earlier patient mobility was noted and the general depression from injectable analgesics was avoided.

Intercostal block for post operative pain relief

Intercostal nerve blocks with 0-5 per cent bupivicaine were used for post operative pain relief in 100 patients having upper abdominal operations. The blocks were very effective in 86 patients and had an average duration of 11 hours. Two asymptomatic pneumothoraces occurred.

Combined axillary plexus block and basal sedation for cardiac catheterization in young children

A technique for the management of cardiac catheterization in children is described which combines axillary plexus block with basal sedation. The technique offers a quiet still arm with pronounced vasodilatation, permitting the use of larger catheters than usual, making sampling easier, and giving undamped pressure records. These factors, together with the absence of venospasm, make catheterization of an arm vein in young chīldren a feasible proposition; in addition arterial sampling via the brachial artery may be performed without further inconvenience to the child.