Canadian Anaesthetists' Society journal
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Clinical Trial Controlled Clinical Trial
Epidural morphine prophylaxis of postoperative pain: report of a double-blind multicentre study.
In a double-blind placebo-controlled trial, 154 subjects, having intraperitoneal surgery or Caesarean section, and 53 patients undergoing lower limb orthopaedic surgery, received epidural morphine, 5 mg in 10 ml 0.9 per cent NaCl, or placebo, 10 ml 0.9 per cent NaCl, intraoperatively to determine duration of action and efficacy in preventing postoperative pain. Epidural morphine gave significantly longer postoperative analgesia (greater than 11 h) than placebo (3-6 h) in both groups (p less than 0.05) and patients who received morphine required less postoperative analgesic. Obstetric subjects experienced longer pain relief (18.3 +/- 1.3 h) than patients undergoing non-obstetric intraperitoneal surgery (9.2 +/- 1.2 h) (p less than 0.001). ⋯ Respiratory depression occurred in 2-7 per cent of subjects who received morphine; unpredictable in onset, it responded rapidly to naloxone. Epidural bupivacaine, if employed for the surgical procedure, appeared to prolong epidural morphine analgesia. We consider epidural morphine useful in preventing postoperative pain, but its use demands close observation of respiratory rate in a high density nursing area.
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It has been suggested that the size of the base of the tongue is an important factor determining the degree of difficulty of direct laryngoscopy. A relatively simple grading system which involves preoperative ability to visualize the faucial pillars, soft palate and base of uvula was designed as a means of predicting the degree of difficulty in laryngeal exposure. The system was evaluated in 210 patients. The degree of difficulty in visualizing these three structures was an accurate predictor of difficulty with direct laryngoscopy (p less than 0.001).
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To determine the effect of intravenous lidocaine on the intraocular pressure (IOP) response to laryngoscopy and intubation, twenty unpremedicated children, ages one to ten years were studied. After administration of either intravenous sterile water (control) (n = 10) or preservative-free lidocaine (1.5 mg X kg-1) (n = 10), anaesthesia was induced with pancuronium (0.15 mg X kg-1), thiopentone (5 mg X kg-1), and atropine (0.02 mg X kg-1), and maintained with halothane, nitrous oxide and oxygen. The trachea was intubated one minute after administration of thiopentone. ⋯ At each measurement (except time 0), IOP was significantly greater in the control group than in the lidocaine group (p less than 0.05). Heart rate and systolic blood pressure did not increase significantly in either group after intubation. We conclude that intravenous lidocaine (1.5 mg X kg-1) significantly attenuates the IOP response to laryngoscopy and intubation in children anaesthetized with pancuronium, thiopentone, and atropine.
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This study determined which variables affected endotracheal tube "leak" pressures in 80 surgical patients, two weeks to 11 years of age, intubated with uncuffed tracheal tubes. We defined "leak" pressure as the inspiratory pressure needed to cause an audible escape of gas around the endotracheal tube. "Leak" pressure was measured after varying either head position, tracheal tube depth within the trachea, fresh gas flow rate, or degree of neuromuscular block. "Leak" pressure increased progressively from 16.9 +/- 1.3 cmH2O with complete patient paralysis to 30.6 +/- 1.4 cmH2O following 100 per cent recovery of neuromuscular function. ⋯ Thus, there may be marked variability in "leak" pressure, depending on head position and degree of neuromuscular blockade. Keeping the patient fully paralyzed with the head in a neutral position provides a reliable and consistent method for measuring "leak" pressures.