Brachial plexus block

A supraclavicular brachial plexus block was performed which resulted in unilateral sensory and motor blockade of the thoracic and abdominal walls. General anaesthesia was therefore used and postoperatively it was noticed that analgesia of the upper limb had developed. It is likely that the blockade resulted from an intrapleural injection of local anaesthetic.     

Intravenous regional anaesthesia of the arm

The effects of different techniques of exsanguination of the upper arm during intravenous regional anaesthesia on prilocaine plasma concentrations, quality of anaesthesia, toxic symptoms after deflation of the tourniquet and injection pressure of the anaesthetic were studied in 10 healthy male volunteers. The nondominant arm was exsanguinated using either Esmarch's bandage or elevation of the arm for 2 minutes plus arterial occlusion by compression of the brachial artery. The injection pressure after the prilocaine dose (3 mg/kg) was significantly higher in the elevation group (maximally 98 mmHg). There were no statistically significant differences in the onset of, or recovery from, anaesthesia between the groups. Various mild toxic symptoms were experienced in the central nervous system after deflation of the tourniquet. However, there was no correlation between the two techniques and the degree of severity of the toxic symptoms. The highest single venous plasma concentration (total) of prilocaine was 2.3 micrograms/ml measured from the contralateral cubital vein (elevation group, 2 minutes). The differences in prilocaine concentrations between the groups were not statistically significant.     

A comparison of lignocaine with prilocaine in axillary brachial plexus anaesthesia

Twenty patients received either lignocaine 1.5% with 1/200,000 adrenaline (group L), or prilocaine 1.5% plain (group P) as a brachial plexus block for surgery to the upper limb, in a randomised double-blind study. The two groups were comparable in age, weight and duration of surgery and there were no significant differences between the two groups with regard to onset, pattern or degree of sensory loss. The degree of motor loss was also comparable. The group L patients had a statistically significant longer duration of sensory loss than those in group P. All the blocks were performed using the same technique and provided complete surgical anaesthesia. Prilocaine 1.5% plain provides adequate sensory and motor blockade for brachial plexus anaesthesia and is a suitable agent for medium duration surgery to the upper limb.     

Comparison of lumbar plexus block versus conventional opioid analgesia after total knee replacement

A randomised controlled study was undertaken to assess the analgesic efficacy of continuous lumbar plexus block for the first 48 hours after total knee replacement surgery. Boluses of 0.5% bupivacaine with adrenaline 1 in 200,000 (0.3 ml/kg) were administered through a cannula inserted into the neurovascular sheath of the femoral nerve. Thirteen patients who received this block required significantly less morphine than a control group of 16 patients. Pain scores were similar and there were no complications related to this technique.     

Incidence of diaphragmatic paralysis following supraclavicular brachial plexus block and its effect on pulmonary function

Thirty unpremedicated ASA physical status 1-3 patients aged between 18 and 69 years, scheduled for upper limb surgery, received a conventional supraclavicular brachial plexus block using a nerve stimulator and bupivacaine 0.375% 0.5 ml.kg-1. Spirometric measurements of pulmonary function and ultrasonographic assessments of diaphragmatic function were made before the block and at 10-min intervals after injection until full motor block of the brachial plexus had developed. Complete paralysis of the ipsilateral hemidiaphragm occurred in 50% of patients. Seventeen per cent of patients had reduced diaphragmatic movement and the rest (33%) had no change in diaphragmatic movement. Those with complete paralysis all showed significant decreases in pulmonary function, whereas those with reduced or normal movement had minimal change. All patients remained asymptomatic throughout, with normal oxygen saturation on room air.     

Effect of transcutaneous electrical nerve stimulation on onset of axillary plexus block

We examined the effect of high frequency transcutaneous electrical nerve stimulation on the onset of brachial plexus block. Three groups of patients scheduled for surgery of the hand had a local anaesthetic block performed with 40 ml mepivacaine 1.5% using the axillary approach. After injection of the local anaesthetic transcutaneous electrical nerve stimulation was applied for 15 min either to the median nerve or the ulnar nerve; no stimulation was applied in the control group. Before and for 45 min after, the injection of local anaesthetic touch perception, pin prick, motor strength andskin temperature were tested by a blinded investigator in the areas supplied by the median, musculocutaneous, radial and ulnar nerves. There were no differences in the onset of block between the groups. Thus, the frequency-dependent action of local anaesthetics could not be demonstrated.     

Latency of brachial plexus block The effect on onset time of warming local anaesthetic solutions

A double-blind study was set up to investigate the effect of warming local anaesthetic solutions on the latency of onset of subclavian perivascular brachial plexus blocks. Twenty-four adult patients were randomly allocated into two equal groups. In group A the local anaesthetic was injected at room temperature, while in group B the local anaesthetic solution was prewarmed to 37 degrees C in a thermostatically controlled heating block. All blocks were performed using 0.5 ml/kg of a solution prepared by mixing equal volumes of 0.5% bupivacaine with adrenaline 1:200,000, and 1% prilocaine. The speed of onset of sensory blockade was significantly increased when the temperature of the local anaesthetic solution was increased to 37 degrees C. There were no adverse side effects in either group.     

EMLA patch for spinal puncture. A comparison of EMLA patch with lignocaine infiltration and placebo patch

We have prospectively assessed pain and anxiety of spinal puncture in 180 adult patients randomly allocated to one of three equal groups. On the morning of surgery group 1 had an EMLA patch, whereas group 2 and 3 had placebo patches. Group 2 also had infiltration analgesia with 2 ml lignocaine 2% with adrenaline, immediately before the block. Spinal anaesthesia was performed with 25 gauge sharp needles without introducer or 25,27 gauge blunt needles with 20,22 gauge introducers. Patients assessed the spinal puncture pain on a 10-cm visual analogue scale immediately after removal of the needle. Pain scores were significantly lower in group 1 (EMLA), median 0.75, than in group 2 (placebo, infiltration analgesia), median 1.75, and group 3 (placebo), median 1.80, p < 0.0001. Pain intensity was less than expected in more patients in the EMLA group than in the other two groups, p = 0.034. However, the decision to accept/reject spinal anaesthesia in the future was not influenced by the pain of lumbar puncture. We conclude that application of an EMLA patch is a simple and effective method to provide adequate analgesia for spinal puncture, which also helps to allay patients' fears of spinal anaesthesia.     

Blood flow in the upper limb during brachial plexus anaesthesia

Changes in finger blood flow, arm blood flow and cardiac output were measured using electrical impedance plethysmography in 20 patients after brachial plexus anaesthesia. The anaesthetic solution used in all patients was 1% lignocaine with adrenaline 1:200,000. Significant increases in cardiac output and blood flow to the unanaesthetised arm were observed immediately after anaesthesia had become effective. A highly significant increase in the blood flow to fingers of the blocked hand was observed throughout the period of anaesthesia but there was no overall increase in the blood flow to the arm. It is suggested that the adrenaline contained in the local anaesthetic solution increased the cardiac output and caused arterial vasoconstriction at the site of injection.     

A comparison of three methods of axillary brachial plexus anaesthesia

One hundred patients scheduled for elective outpatient hand surgery had blockade of the axillary brachial plexus by one of three techniques; insertion of a catheter into the brachial plexus sheath (n = 25), use of paraesthesia (n = 50) or use of the nerve stimulator (n = 25) to localise the plexus. Only two patients required general anaesthesia for the planned surgery. Assessment of the dermatomes blocked did not demonstrate a statistical difference between the success rates of the three groups. The more nerves detected in the paraesthesia and the nerve stimulator groups before injection of local anaesthetic the higher the success rate of the block. We advocate use of the nerve stimulator technique in view of the possible risk of neurological damage associated with paraesthesia and the technical difficulties with the catheter technique, for routine brachial plexus blockade.     

Plasma concentrations of bupivacaine during extradural anaesthesia for Caesarean section

The clinical effects and plasma levels associated with the use of 0.5% bupivacaine with and without the addition of 1:200,000 adrenaline (5 micrograms/ml) were studied in 30 patients who underwent extradural anaesthesia for elective Caesarean section. The addition of adrenaline to bupivacaine prolongs analgesia, reduces the degree of hypotension and delays its onset. Plasma bupivacaine levels were consistently lower when adrenaline was added, but this difference was significant only at 10 minutes after the initial dose. Prolonging the interval between increments seems to be a more reliable way to reduce plasma concentration than the addition of the catecholamine.     

Enhanced brachial plexus blockade. Effect of pain and muscular exercises on the efficiency of brachial plexus blockade

Three groups each of 20 patients scheduled to undergo operations on hand or forearm, received supraclavicular brachial plexus blocks with 25 ml lignocaine 1.5%. Patients in the control group did not suffer from pain and were not asked to do muscular exercise. Patients with acute trauma of the upper limb formed the pain group and showed significantly decreased latency for onset of analgesia, partial and complete muscle paralysis. Patients in the muscle exercise group were free of pain and were asked to do muscular exercise for 5 minutes after injection of the lignocaine. Onset of analgesia, partial and complete muscle paralysis was significantly more rapid than in both control and pain groups. Changes in the duration of block were not significant. It is concluded that pain and muscular exercise enhance the onset of brachial plexus blockade.     

Continuous blockade of the lumbar plexus after knee surgery—postoperative analgesia and bupivacaine plasma concentrations

In a double blind, randomised, controlled investigation the analgesic effect of a continuous block of the lumbar plexus with bupivacaine compared with sodium chloride was examined in 20 patients with postoperative pain after knee-joint surgery. The infusion was given through a catheter inserted in the neurovascular fascial sheath of the femoral nerve, according to the three-in-one block technique. The patients treated with bupivacaine had significantly lower pain scores and a significantly lower demand for morphine. Side effects related to the catheters or the infusions of bupivacaine were not observed.