ADVERSE EFFECTS OF EXTRADURAL AND INTRATHECAL OPIATES: REPORT OF A NATIONWIDE SURVEY IN SWEDEN

The Swedish Society of Anaesthetists conducted a nationwide retrospective survey of clinical experience with extradural and intrathecal opiates Special interest was focused on the frequency and type of ventilatory depressfon. The questionnaire was answered by 84 of 93 departments (90%). Up to May 1981 extradural morphine had been given to approximately 6000-9150 patients, extradural pethidine to 220-450 and intrathecal morphine to 90-150 patients Ventilatory depression requiring treatment with naloxone was reported in 23 patients treated with extradural morphine (0.25-0.40%) and in six given uitrathecal morphine (4_7%). In 22 patients the administration of extradural morphine was considered as a major contributory factor for the occurrence of ventilatory depression Only two of these 22 patients experienced ventilatory depression later than 6h after the last dose of opiates (s.c, i.m., i.v. or extradural). Patients aged 70yror more, those receiving thoracic extradural puncture and those with reduced ventilatory capacity seemed to be oyerrepresented In 1979 it was demonstrated that small doses of morphine given intrathecally and extradurally pro-duced long-lasting relief of chronic and postopera-tive pain in man (Bahar et al., 1979; Wang, Nauss and Thomas, 1979). The practice of this promising technique to achieve selective spinal analgesia has been hampered by the lack of controlled clinical studies (Editorial, 1980) and by reports of adverse reactions (Editorial, 1980; Reiz and Westberg, 1980; Yaksh, 1981). Pruritus and urinary retention are frequent side-effects (Reiz and Westberg, 1980; Samii, Chauvin and Viars., 1981). An alarmingly high frequency of late respiratory depression after intrathecal administration (Davies