Atracurium for intubation in man. A clinical and electromyographic study.

Atracurium is a new competitive neuromuscular blocking agent. We prospectively studied intubating conditions 2.5 minutes after atracurium doses of 0.4 or 0.5 mg/kg. For comparison, we evaluated conditions 1 minute after suxamethonium 1.0 mg/kg, there being 10 patients in each group. The same anaesthetist evaluated conditions during laryngoscopy and intubation in all patients. Intubating conditions were excellent in 33% of patients receiving atracurium 0.4 mg/kg and 60% of those receiving atracurium 0.5 mg/kg after 2.5 minutes; conditions were excellent in 80% of patients 1 minute after suxamethonium. The incidence of successful intubation on the first attempt was 67%, 90%, and 100%, respectively, in the three groups. Atracurium may be a suitable alternative to suxamethonium when speed of intubation is not critical.

Atracurium during halothane anesthesia in humans.

The neuromuscular effects of atracurium were studied in 20 patients anesthetized with 0.8% end-tidal halothane. Neuromuscular blockade was monitored by recording the electromyographic activity of the adductor pollicis muscle resulting from stimulation of the ulnar nerve. Four groups of five patients received single atracurium doses of 0.1, 0.15, 0.2, or 0.4 mg/kg, respectively. The block produced by 0.1 mg/kg was 25-72% and lasted 6-21 min. The block produced by 0.15 mg/kg was 69-93% and lasted 16-32 min. The blocks produced by 0.2 and 0.4 mg/kg were 95% or greater and lasted 42-84 min and 55-104 min, respectively. When indicated, intubation was easily performed in all patients receiving 0.2 and 0.4 mg/kg. The block could be readily antagonized by neostigmine and atropine. Changes in heart rate and blood pressure following atracurium administration averaged less than 5%.

Modification of atracurium blockade by halothane and by suxamethonium. A review of clinical experience.

The effects of halothane and of prior administration of suxamethonium on atracurium neuromuscular blockade have been investigated. Halothane potentiated the intensity of block produced by atracurium 0.1 or 0.15 mg kg-1. Duration of block was prolonged (27%) by halothane with a small dose of atracurium (0.15 mg kg-1) and was also prolonged (29%) with larger doses of atracurium (0.4 mg kg-1). Prior suxamethonium 1 mg kg-1 increased the intensity of block after atracurium 0.15 mg kg-1 from 52% (control) to 84%, but caused minimal change in duration of atracurium blockade.

Comparison of i. m. diazepam and hydroxyzine as premedicants.

The effectiveness of diazepam as premedication when administered by two different i.m. techniques was compared with hydroxyzine in 84 male and 101 female patients. Variables studied were relief of anxiety, sedation, acceptance by both patient and anaesthetist and pain at the injection site. Diazepam 20 mg in male and diazepam 10 mg in female patients administered by a Z-track injection technique were as effective premedicants as hydroxyzine 100mg i.m. In men diazepam was good as hydroxyzine regardless of the injection technique. In women the technique of injection of the diazepam was critical to achieving good results. The Z-track injection method decreased the amount of severe pain on injection in both sexes to levels similar to those achieved with hydroxyzine.

Lorazepam and morphine for i.v. surgical premedication.

The effect of i.v. lorazepam alone, in doses of 2 mg and 4 mg, and combined with morphine 5 mg, were studied. Sedation, relief of anxiety, lack of recall, patient acceptance, physician acceptance and side-effects were evaluated. The addition of morphine to lorazepam significantly improved sedation and relief of anxiety. Physician acceptance and patient acceptance showed no significant difference between any of the combinations. Lack of recall was enhanced by increasing the dose of lorazepam from 2 mg to 4 mg, independent of the addition of morphine. The only significant side-effect was restlessness which occurred in 15% of patients receiving lorazepam 4 mg and 3% of patients receiving lorazepam 2 mg, again independent of the addition of morphine.

Diazepam and droperidol as i.v. premedicants.

The effects of i.v. diazepam and droperidol both alone and in combination administered as premedication were studied in 240 patients. Relief of anxiety, sedation, lack of recall, acceptance by both patient and physician and side-effects were evaluated. Overall, the combination of droperidol 2.5 mg with diazepam 5 mg produced better ratings of these variables than could be achieved with either droperidol 10 mg or diazepam 10 mg alone. Larger doses of droperidol with diazepam produce an increased frequency of anxiety; larger doses of diazepam with droperidol may cause over-sedation.

Droperidol, fentanyl and morphine for i.v. surgical premedication.

Fentanyl 0.1 mg and morphine 10 mg alone and in combination with droperidol 2.5 and 5.0 mg were studied for i.v. surgical premedication in 240 patients. Relief of anxiety, sedation, lack of recall, patient acceptance and side-effects were evaluated. The addition of droperidol to fentanyl and morphine produced greater sedation and relief of anxiety before operation, but did not improve patient acceptance or lack of recall.

Lorazepam, hyoscine and atropine as i.v. surgical premedicants.

Lorazepam 2 and 4 mg alone and in combination with atropine 0.4 mg and hyoscine 0.4 mg were studied as i.v. surgical premedicants in 150 patients. Relief of anxiety, sedation, patient acceptance, lack of recall and side-effects were evaluated. Hyoscine was found to improve the relief of anxiety and sedation associated with lorazepam, but did not significantly increase lack of recall or patient acceptance. The addition of atropine to lorazepam did not significantly alter its effects. A high frequency of agitation and restlessness in patients receiving lorazepam and hyoscine make this combination undesirable for surgical premedication.

Comparison of i.v. diazepam and hydroxyzine as surgical premedicants.

Diazepam and hydroxyzine as i.v. surgical premedicants were compared. A double-blind randomized sequence was used employing 7.5 and 15 mg of diazepam v. 75 and 150 mg of hydroxyzine. Each group consisted of 35 patients. Anxiety relief, sedation, lack of recall and patient acceptance were the principal assessments. Diazepam was superior to hydroxyzine in all respects. No serious side-effects were noted with either drug.