Epidural diamorphine for post-caesarean pain: a dose response study.

The effectiveness of postoperative pain relief and the frequency of side effects with three different doses of epidural diamorphine (2.0, 3.5 and 5 mg) was investigated. The study was carried out double-blind in 30 women undergoing awake elective caesarean section. Postoperative pain intensity was measured on a linear analogue scale. The time to onset of analgesia (TOA), time taken to reach a pain score of zero or become comfortable, and time to next analgesia (TNA) were not significantly different between groups. Three patients in the 2 mg group failed to achieve scores of zero but were comfortable. No nausea or vomiting was seen but the incidence of itching was 0, 30% and 80% in the 2.0, 3.5 and 5 mg groups respectively. We conclude that epidural diamorphine 2 mg is adequate for relief of post-caesarean pain and higher doses may increase the incidence of unwanted side-effects.

Tracheal tube resistance and airway and alveolar pressures during mechanical ventilation in the neonate.

The relationship between peak airway pressure, alveolar pressure and respiratory frequency was calculated for the range of compliances and airway resistances which might be encountered during mechanical ventilation of a 3-kg neonate. The pressure/flow relationships of 2.5, 3.0, 3.5 and 4-mm tracheal tubes were determined at a series of flows from 0.5 to 4 litres/minute. Peak airway and alveolar pressures were then measured at various frequencies and inspiratory:expiratory ratios with the tubes incorporated in a model lung. Large differences between peak airway and alveolar pressures developed when frequency was increased or inspiratory time decreased; the differences were greatest with the smaller tubes. Shortening expiratory time by increasing the frequency or altering the inspiratory:expiratory ratio resulted in increased end-expiratory pressure because of incomplete emptying of the lung.

Triazolam premedication. A comparison with lorazepam and placebo in gynaecological patients.

A randomised, double blind study, of 58 female patients undergoing laparoscopic investigation was carried out to compare triazolam 0.25 mg, lorazepam 2 mg, or placebo as oral premedication. Each patient was assessed by only one of the authors both pre- and postoperatively with regard to anxiolysis, sedation and rapidity of recovery. Triazolam and lorazepam were each associated with a significant reduction in anxiety compared to the initial assessment, whereas placebo had no anxiolytic effect. Sixty minutes after premedication, patients who had received triazolam were significantly more sleepy than patients given placebo or lorazepam. Two hours after the operation, the patients who had had triazolam or lorazepam were significantly more sleepy than those who received placebo. However, at 6 hours postoperatively there was no difference between triazolam and placebo, whilst those who had been given lorazepam were still significantly more sleepy than those given placebo. Triazolam appears to offer advantages over either lorazepam or placebo in patients who require rapid recovery, sedation and reduction in pre-operative anxiety.