Perivascular axillary block VII: the effect of a supplementary dose of 20 ml mepivacaine 1% with adrenaline to patients with incomplete sensory blockade.

Perivascular axillary blockade was performed on 233 patients with the aid of a catheter technique. All patients received a primary injection of 50 ml of mepivacaine 1% with adrenaline. Sensory blockade was evaluated 20, 30 and 40 min after injection, and a complete sensory blockade was found in 90 (39%), 131 (57%) and 146 (63%), respectively. The blockade effect of a supplementary perivascular injection of 20 ml of the same agent was investigated on the remaining 87 blockades, which could be divided into three categories: blockades which at 20 min showed lack of analgesia in several cutaneous segments of the hand (34 patients); blockades which at 30 min showed a total lack of sensory blockade within a limited area (29 patients); and blockades which at 40 min showed signs of blockade of all cutaneous segments, but one or several segments were not blocked with an intensity compatible with surgery (24 patients). Blockades of categories 1 and 2 were at 20 and 30 min, respectively, randomly allocated to control or to perivascular supplementation groups, while blockades of category 3 all had supplementation at 40 min. Sensory blockade was reevaluated 10 and 20 min after group allocation, and it was found that perivascular supplementation had no significant effect on the sensory blockade in category 1 and 2, while 68% of the blockades in category 3 improved to a complete blockade.(ABSTRACT TRUNCATED AT 250 WORDS)

Perivascular axillary block VI: the distribution of gelatine solution injected into the axillary neurovascular sheath of cadavers.

Axillary perivascular injection of 50 ml blue-stained gelatine was made in 20 cadavers, and a total dissection of the axilla was performed. The distribution of injected gelatine and the contact between nerves and gelatine were examined on cross-sections of the neurovascular bundle. The spread of gelatine was characterized by: restriction of gelatine to the neurovascular bundle, an upper border of the gelatine which was constantly found to be proximal to the coracoid process, and bulging of the gelatine towards the medial part of the axillary space. Cross-sections of the neurovascular bundle showed the nerves and vessels to be located in the periphery of the gelatine and in close contact with the lateral wall of the axillary space. The median and the ulnar nerves were in all dissections found to be in direct contact with the gelatine, whereas the radial, the musculocutaneous, and the axillary nerves did not always have direct contact with the gelatine. Abduction of the arm to 90 degrees brings the stretched neurovascular bundle close to the lateral wall of the axilla and this compromises perivascular circumferential spread of the injected gelatine. On the basis of the present investigation, it is hypothesized that insufficient circumferential spread is the cause of incomplete axillary blockades, and the perivascular injection of local anaesthetic should consequently be made with the arm along the side of the body.

Perivascular axillary block V: blockade following 60 ml of mepivacaine 1% injected as a bolus or as 30 + 30 ml with a 20-min interval.

Perivascular axillary blockade was performed on 60 patients with the aid of a catheter technique. The patients were randomly allocated to two groups. All patients received the same dose of local anaesthetic: 60 ml of mepivacaine 1% with adrenaline, but one group received the dose as a bolus injection, whereas the other group received the dose as fractional injections of 30 + 30 ml with an interval of 20 min. Blood concentrations of mepivacaine were measured up to 90 min after injection of local anaesthetic. Sensory and motor blockade were evaluated 20, 30 and 40 min after injection. Forty minutes after the last injection of local anaesthetic, there was no difference between the blockades of the two groups, except for the sensory blockade of the lower lateral cutaneous nerve of the arm, in which the frequency of analgesia was 90% after bolus injection and 63% after fractional injections. There was no difference in blood concentrations of mepivacaine between the two groups. None of the 60 patients showed any sign of systemic toxic reactions. Fractional injection of local anaesthetic in perivascular axillary blockade does not offer any advantage over bolus injection with regard to the resulting blockade.

Perivascular axillary block III: blockade following 40 ml of 0.5%, 1% or 1.5% mepivacaine with adrenaline.

Perivascular axillary blockade was performed on 90 patients with the aid of a catheter technique. All blockades were performed by the same anaesthetist, who practised perivascular axillary blockade three or four times a day. The patients were randomly allocated to three groups. The injected volume of local anaesthetic was constant in each group: 40 ml mepivacaine with adrenaline. The concentration and, consequently, the amount (mg) were variable factors: 1/2% (200 mg), 1% (400 mg) and 1 1/2% (600 mg). Sensory and motor blockade were tested 30 min after each injection. All three groups showed a high incidence of analgesia (70%-100%) in all cutaneous segments, and none of the blockades showed total failure of the sensory blockade. The lowest incidence of sensory blockade was found in the areas innervated by the axillary, the radial and the musculocutaneous nerves, but no difference was found between the groups. However, the motor blockade was found to improve with increasing concentration of local anaesthetic solution.

Perivascular axillary block IV: blockade following 40, 50 or 60 ml of mepivacaine 1% with adrenaline.

Perivascular axillary blockade was performed on 90 patients with the aid of a catheter technique. The patients were randomly allocated to receive either 40, 50 or 60 ml of 1% mepivacaine with adrenaline 1:200,000. Blood concentrations of mepivacaine were measured up to 90 min after injection in seven, eight and ten of the patients from the three groups. Sensory and motor blockade was evaluated 20, 30 and 40 min after injection. All groups showed the same temporal development of the blockade, i.e. improval of the blockade during the period from 20 to 40 min after injection, but no difference was found in the sensory or motor blockade between the three groups. However, a further analysis of the incomplete blockades showed a better quality of the sensory blockade in the groups given 50 and 60 ml than in the group given 40 ml. None of the 90 patients showed any signs of systemic toxic reactions. The mean peak values of blood concentrations were 0.5-1.0 microgram/ml higher in the groups given 50 ml and 60 ml than in the group given 40 ml. On the basis of the present and two previous investigations on the dose response in perivascular axillary blockade, a dose of 50 ml 1% mepivacaine with adrenaline or another equivalent drug with vasoconstrictor is recommended.

Electroconvulsive therapy and intracranial aneurysm. Prevention of blood pressure elevation in a normotensive patient by hydralazine and propranolol.

A 42-year-old normotensive woman developed a severe mental depression 6 months after an operation for intracranial aneurysm. The use of electroconvulsive therapy (ECT) was judged to be of vital importance. By concurrent administration of intravenous hydralazine and propranolol before induction of anaesthesia the normally occurring ECT-induced blood pressure elevation was completely prevented, and the patient received a series of ten ECTs without complications.

Perivascular axillary block II: influence of injected volume of local anaesthetic on neural blockade.

Perivascular axillary blockade was performed on 150 patients with the aid of a catheter technique. Blockade failure due to injection outside the neurovascular sheath was found in 5.7% of the subject material. The patients were randomly allocated to three groups. The amount of local anaesthetic was constant in each group: 400 mg mepivacaine with adrenaline. However, the injected volume was a variable factor, namely 20, 40 or 80 ml. Sensory and motor blockade was tested 30 min after each injection. The following results were obtained: 1) Apart from the axillary, musculocutaneous and radial nerves, a high frequency of analgesia was found in all cutaneous areas (over 85%). 2) In the axillary area, improvements were found with increasing volume. 3) Analgesia in the musculocutaneous area occurred in 52% of the patients in group 1 (20 ml) and improved to 75% in group 2 (40 ml). However, no difference was found between group 2 and group 3 (80 ml). 4) Volume had no influence on analgesia in the radial area. 5) Motor blockade was intensified with decreasing volume, i.e. with an increase of concentration of local anaesthetic solution.

Epidural morphine for postoperative pain relief.

In a clinical, double-blind study including 45 patients, who all underwent lower abdominal or urological surgery, the analgesic effect, latency and duration of epidural application of morphine were investigated in doses of 2 and 4 mg, respectively, compared to placebo. No significant difference was found in the effect of 2 mg morphine, compared to placebo. A significant decrease in pain score was found in the group of patients who received 4 mg morphine administered epidurally; however, this effect did not occur until 60 min after epidural administration. The effect of 4 mg morphine was found to be of long duration, as eight out of 15 patients did not require any supplementary analgesics within the first 24 h, compared to two out of 14 and three out of 15 patients, respectively, in the placebo and 2-mg groups.

Respiratory depression and morphine concentration in serum after epidural and intramuscular administration of morphine.

The ventilatory response to carbon dioxide and the serum level of free morphine were measured in six adult patients scheduled for operation under lumbar epidural analgesia. The investigation was performed on 2 consecutive days before the operation. The measurements were performed before, and 30 and 90 min after the intramuscular administration of morphine chloride (0.15 mg/kg body weight) as well as lumbar epidural administration of morphine chloride (5 mg morphine chloride diluted in 10 ml isotonic saline). The ventilatory response to carbon dioxide was depressed significantly both 30 and 90 min after epidurally administered morphine compared to the control value, while the depression of the ventilatory response was demonstrated in only five of six patients 30 min after intramuscularly administered morphine. The peak serum levels of free morphine were reached within 20 min of administration and it seemed that the injected quantity of morphine and not the method of administration determined the serum level.

Perivascular axillary block. I: blockade following 40 ml 1% mepivacaine with adrenaline.

Perivascular axillary block was performed on 80 patients by a catheter technique. All patients had a standard dose of 40 ml mepivacaine 1% with adrenaline. Thirty minutes after the injection, the motor and sensory blockade was determined. Eighty-six per cent of the patients had a distinct motor blockade, whereas the remaining 14% had only a slight motor blockade. The sensory blockade was complete in 63%, whereas 37% had lack of analgesia in one or several cutaneous areas. Lack of analgesia was most often found in the cutaneous area of the axillary, musculocutaneous and radial nerves. The frequency of analgesia in the three areas of innervation was analysed with reference to the influence of the age, height and weight of the patient, and of differences in technique: paraesthesias, position of catheter, and unintended puncture of blood vessels. None of these variables seems to be important for the low frequency of analgesia in the three areas of innervation.

Interscalene brachial plexus block: area of analgesia, complications and blood concentrations of local anesthetics.

In a prospective clinical study including 100 patients, the consequences of using the interscalene approach to block the brachial plexus were investigated according to the area of analgesia, complications, and blood concentrations of local anesthetics. Sufficient analgesia of the shoulder and the upper part of the arm was obtained in 98-99% of the cases, whilst the area of analgesia in the forearm and the hand was more variable. In two groups, with 10 patients in each group, the blood concentration was measured during the first 50 min after injection in the neurovascular sheath by either the interscalene or the axillary approach. The peak values were at the same level in the two groups, but there was a much more rapid rise in concentration in the interscalene group. No toxic reactions were seen. The complications were in accordance with those reported in other publications.

Influence of epidural analgesia on the catecholamine and cyclic AMP responses to surgery.

The effects of neurogenic block on plasma concentrations of adrenaline, noradrenaline and cyclic AMP were studied. Eighteen patients were subjected to surgery of moderate or minor extent under enflurance anesthesia with or without epidural analgesia. The results show that adrenaline secretion during surgical stress is a response to neurogenic stimuli, since the increase found in patients subjected to hysterectomy under general anesthesia is blocked by the addition of epidural analgesia. Furthermore, plasma adrenaline after neurogenic block is comparable with adrenaline levels during minor surgical stress. The plasma noradrenaline concentration does not correlate with the extent of trauma. In contrast to adrenaline levels, noradrenaline concentrations varied insignificantly during and after surgery. However, the addition of epidural block induced a postoperative increase in noradrenaline apparently unrelated to changes in heart rate or blood pressure. Simultaneous measurements of the catecholamines and cyclic AMP indicate that adrenaline is of minor importance for plasma cyclic AMP in resting patients, whereas the increase in cyclic AMP elicited by surgery reflects adrenaline-stimulated beta-adrenergic activity.

Cyclic AMP, adrenaline and noradrenaline in plasma during surgery.

Plasma concentrations of cyclic AMP, adrenaline and noradrenaline were measured in 6 patients undergoing hysterectomy from before induction of anaesthesia to 6 h after skin incision. Noradrenaline did not vary significantly during the observation period, whereas cyclic AMP and adrenaline increased after skin incision. A significant correlation was found between plasma concentrations of cyclic AMP and adrenaline (r = 0.84, P less than 0.01), suggesting that the latter is responsible for the increase in plasma cyclic AMP which is observed in relation to surgical procedures. Peak concentrations of cyclic AMP and adrenaline were seen in the early postoperative phase. This indicates that the most pronounced acute endocrine stress response to surgery of moderate severity occurs after termination of anaesthesia.