D. A. Cozanitis

Bradycardia associated with the use of vecuronium. A comparative study with pancuronium with and without glycopyrronium

One hundred and twenty patients undergoing anaesthesia for elective surgery received either pancuronium or vecuronium for muscle relaxation. Within each of these two groups, half were given glycopyrronium and the remainder an inert placebo. The incidence of bradycardia or bradydysrhythmias was higher in the group having vecuronium compared with those given pancuronium. Glycopyrronium afforded protection against undesirable vagal activity.

Galanthamine hydrobromide versus neostigmine. A plasma cortisol study in man.

Galanthamine hydrobromide (Nivalin, Pharmachim, Sophia, Bulgaria), the result of Bulgarian and Russian work, is an anticholinesterase drug whose chemical structure closely resembles that of morphine (Fig. 1). Possession of a tertiary ammonium group enables the drug to traverse the blood-brain barrier, giving it central action in addition to its peripheral activity. Naumenko, llyuchenko & Nesterenkol found that a subcutaneous injection of galanthamine hydrobromide caused an increase in 17-hydroxycorticosteroid blood levels in guinea-pigs and, in another study, conscious epileptic volunteers receiving

The oculocardiac reflex in adults.: A dose response study of glycopyrrolate and atropine

Ninety adult patients about to undergo strabismus surgery received glycopyrrolate or atropine intramuscularly. Three doses of each anticholinergic were studied. Cardiac rate and rhythm were recorded during halothane anaesthesia. The oculocardiac reflex, defined as a fall of 20% in heart rate during traction of the extraocular muscle was inhibited in a dose‐dependent manner by the drugs studied. The potency ratio of glycopyrrolate to atropine according to the oculocardiac reflex was established as 1:2.

A clinical study into the possible intrinsic bradycardic activity of vecuronium

Forty female patients received a standardised anaesthetic technique with thiopentone sodium and enflurane. Half of the patients received, under double‐blind conditions, either physiological saline or glycopyrronium before induction of anaesthesia; 10 minutes after induction of anaesthesia, all patients received vecuronium 0.1 mg/kg. A further 10 patients received neither glycopyrronium nor vecuronium. The results show that vecuronium per se does not produce a decrease in heart rate.

Bradycardia in patients receiving atracurium or vecuronium in conditions of low vagal stimulation

Four groups of 20 patients each received either vecuronium or atracurium together with either glycopyrronium or saline, and underwent anaesthesia free of vagolytic drugs, and surgery devoid of vagal activity. Determinations of plasma histamine concentrations were made to examine the possible correlation between these levels and changes in heart rate and blood pressure as well as a possible relationship with skin reactions after the administration of the relaxants. Patients who received vecuronium without the anticholinergic drug, glycopyrronium, showed a greater tendency towards bradycardia (though not statistically significant) than those given atracurium. More cutaneous reactions were observed with patients who received atracurium than in those with vecuronium, but there was no correlation with plasma histamine concentrations of either relaxant group. There was no correlation either between histamine concentrations and heart rate or blood pressure associated with atracurium. The incidence of bradycardia with either relaxant is low if the anaesthetic technique and the surgery are devoid of vagal activity.

Precurarisation in infants and children less than three years of age

Sixty patients less than three years of age about to undergo adenoidectomy or endoscopy were divided into three groups of 20 each according to age (0-11 months, 12-23 months, 24-35 months). Before the induction of anaesthesia with thiopentone, either tubocurarine 0.05 mg.kg-1 or normal saline was given at random in a double-blind fashion. Three minutes later, the children received succinylcholine 1.5 or 1 .Omg.kg-1, respectively. Muscle movements were graded according to a four-point scale. Blood was sampled for creatine kinase (CK) activity before anaesthesia and on the following morning. When all age groups were combined, there was a significant reduction of muscle movements in patients who had received tubocurarine pretreatment. Serum CK activity rose significantly when saline pretreatment was used in children over the age of one year but not in the infants, despite the presence of muscle movements following succinylcholine administration.RésuméSoixante patients tous âgés de moins de trois ans et devant subir une adénoidectomie ou une endoscopie, ont été divisés selon ľâge en trois groupes de 20. Avant ľinduction de ľanesthésie avec thiopentone, soit de la DTC 0.05 mg-kg-1 ou du salin physiologique a été administré au hasard et à double insu. Trois minutes plus tard les enfants ont reçu respectivement de la succinylcholine 1.5 ou 1.0 mg-kg-1. Les mouvements musculaires ont été gradés ďaprès une échelle à quatre points. Du sang a été retiré pour ľactivité de la creatinine kinase (CK) avant ľanesthésie et le lendemain matin. Quand tous les groupes ont été combinés on a noté une diminution significative des mouvements musculaires avec le pré-traitement à la DTC. Ľactivité sérique de la CK s’éleva significativement quand le pré-traitement au salin physiologique était utilisé pour les enfants dont ľâge est supérieur à un an et non chez ceux âgés de moins ďun an malgré les fasciculations musculaires.

Influence of laryngoscope design on heart rate and rhythm changes during intubation

One hundred and twenty adult patients about to undergo surgery were premedicated with either meperidine or meperidine and atropine. After anaesthesia was induced with thiopentone and succinylcholine given, tracheal intubation was performed with the use of either a Magill or a Macintosh laryngoscope. There were no statistical differences in changes of heart rate and rhythm between the groups, as regards the type of premedication given or the design of laryngoscope used.RésuméCent-vingt patients devant subir une chirurgie ont été prémédiqués avec de la mépéridine ou de la mépéridine et de l’atropine. Ensuite on débutait Vanesthésie avec du thiopenial et de la succinylchoiine puis on procédait à l’intubation endotracheale avec une lame Macintosh ou une lame Magill. ll n’y a eu aucune différence significative dans les changements de la fréquence et du rythme cardiaque dans les différents groupes peu importe le type de prémédication ou le type de lame utilisé.

Skin reactions to the newer non-depolarising neuromuscular blocking drugs.

was probably only a few millilitres on each occasion. This time the catheter passed easily and a satisfactory block was produced with 8 mlO.S% plain bupivacaine (4 ml on each side). The patient obtained good pain relief. One top-up of 8 ml was required. A forceps delivery of a healthy infant was performed. No supplementary analgesia was needed. The next day the patient complained of a strange crackling sensation on turning her head. On examination she was found to have surgical emphysema in the extensor muscle compartment on the right side of her neck, beneath the deep cervical fascia. This was confirmed by neck x-ray. Chest x-ray was normal: there was no pneumomediastinum nor pneumothorax. The emphysema disappeared over the next 3 days. The patient remained well apart from the fifth day after delivery, when she complained of severe backache radiating to her neck. Her temperature remained normal. These symptoms resolved and mother and baby were discharged home the next day. Pneumomediastinum is an unusual but well recognised complication of labour, resulting from alveolar rupture caused by high intrathoracic pressure generated by ‘bearing down’ efforts. This presents during labour with chest pain, and widespread subcutaneous emphysema of the face, neck, trunk, and arms. Chest x-ray confirms pneumomediastinum. 1.2 This patient presented in a different manner: she had no chest pain, and the emphysema was not subcutaneous but was limited to the deep tissues of the back of her neck on palpation. She had no x-ray evidence of pneumomediastinum. The epidural was effective so that she did not strain at delivery, and there was a delay of some hours before onset of symptoms. These points led the writer to believe the epidural may have been responsible. A consideration of the epidural space and the factors affecting it during pregnancy and labour (as set out below) lends support to this view. Firstly, the anatomy: in 1947 Macintosh and Mushin3 demonstrated that the epidural space is not a closed cavity but communicates freely with the paravertebral spaces via the intervertebral foramina. Bum4 confirmed, using contrast media, that solutions spread easily thoughout the epidural space and that leakage through intervertebral foramina is common, particularly in young subjects. Secondly, the pressures in the epidural space: during ‘bearing down’ in the second stage dramatic pressure increases of 2-6 kPa can o c c ~ r . ~ . ~ Injections into the epidural space can also cause pressure increases of about 3.0 kPa.’ Finally, complex changes in the structure of connective tissue occur towards the end of pregnancy: collagen fibres which are normally packed tightly together become widely scattered. These changes are most evident in the birth canal, but they also occur t o some extent in all connective tissue structures,8 presumably including those in and around the vertebral column. Thus the epidural space, which is not normally a closed cavity, may be more ‘open’ than usual at tern, and is subjected to unusually high increases in pressure. Under these conditions pressure changes in the lumbar epidural space could be transmitted, with little attenuation, to the thoracic and cervical regions and thence to the paravertebral tissues via the intervertebral foramina. In the neck an escape of air by this route would occur directly into the extensor muscle compartmenL9 The air would remain trapped here since this compartment is tightly bound by the prevertebral fascia anteriorly and the deep cervical fascia posteriorly. The writer would be pleased to hear whether anyone else has observed emphysema in the neck following an obstetric epidural: if so, it would lend support to the above hypothesis.

Aneurysm of ventilator tubing. A warning.

In the Third Surgical Clinic of Helsinki University Central Hospital, six Engstrom ventilators (Model 200) have been in use for the past five years for administering anaesthesia. During this period five cases of internal ‘aneurysm’ have been noted in the patients’ tubing. In four of the cases, the fault was detected in the routine checking of the ventilator which is undertaken before each operation (figure 1). However, in the fifth case, the ‘aneurysm’ occurred spontaneously while the patient was being ventilated (figures 2 and 3).

Ulnar nerve stimulation in the thick arm

Dr Hunter and her colleagues (Anaesthesia 1985; 40: 916) raise an interesting point about stimulation of the ulnar nerve in the forearm of oedematous, and also in obese or muscular, patients. The use of needle electrodes might conceivably result in direct stimulation of the muscle or damage to the nerve. My practice in this circumstance is to connect the positive electrode of the neurostimulator to a paste electrode over the medial epicondyle, rather than to the orthodox position of the wrist region. The ulnar nerve passes in close proximity to the electrode at the elbow and the response of the muscles, if it is to be seen at all, is good.