We compared patient-controlled analgesia (PCA) and continuous infusion (CI) morphine delivery in a randomized controlled trial in adolescents during oropharyngeal mucositis pain after bone marrow transplantation. Results from 20 patients who completed 7 or more days on study (10 PCA, 10 CI) were evaluated. The group means for age, weight and height were comparable. Daily measures were morphine intake, self-report of pain intensity and side effect scores. Over 10 study days, the mean cumulative morphine dose to subjects in each group was 4.94 mg/kg (PCA) vs. 12.17 mg/kg (CI); the difference is significant (P less than 0.01). No significant differences were found between the groups for patient ratings of pain intensity or side effect scores despite the large difference in mean morphine intake, but the PCA group tended to report less intense sedation and less difficulty concentrating. Adolescents can use PCA effectively and safely for 1-3 weeks. Morphine intake of adolescent patients using PCA morphine intake is significantly lower than that of similar patients receiving staff-controlled CI.

Summary A case in which a mediastinal tumour caused complications including airway obstruction unrelieved by intubation during inhalational induction is described. Other case reports are reviewed and the anasthetic management of patients with mediastinal tumours is discussed.

1 We compared the effects of dopexamine, dopamine and dobutamine on the heart rate, blood pressure and renal blood flow of six healthy volunteers in an open triple crossover trial. 2 The results suggest that at the dose ranges investigated dopamine was the most effective agent for increasing renal blood flow.

Microprocessor-controlled infusion pumps, which allow a patient to self-administer bolus doses of an analgesic to relieve pain, are becoming commonplace. While these patient-controlled analgesia (PCA) systems overcome the large interpatient variations in pharmacokinetics, they do not provide steady relief from pain since they rely on delivering a drug in small, incremental doses. To overcome this problem, the authors developed an algorithm and computer-pump system that allows patients to control their own plasma concentration of analgesic. This approach uses individually predetermined pharmacokinetic parameters to provide steady plasma opioid concentrations that can be increased or decreased by the patient in line with the need for more pain relief or fewer side effects. The control software uses a novel, recursive algorithm to compute the pump rates necessary to maintain constant plasma drug (e.g. morphine) concentrations at desired values and to reach a new steady concentration in response to patient requests. This report describes the mathematical approach to the problem of control of plasma opioid concentration, the application of this new drug delivery system to management of persistent pain in cancer patients undergoing bone marrow transplantation, and the magnitude of pharmacokinetic variability with morphine in this patient population. Results are presented from individual patients using this adjustable drug delivery system continuously for up to 2 weeks to control pain from oral mucositis.