INTRATHECAL MORPHINE FOR POST-STERNOTOMY PAIN IN PATIENTS WITH MYASTHENIA-GRAVIS - EFFECTS ON RESPIRATORY-FUNCTION

Background: Thymectomy can induce a remission or at least an improveme nt in myasthenia gravis (MG) patients. After sternotomy MG patients wi th compromised muscle strength need an excellent postoperative pain re lief. This study was designed to evaluate the efficacy of intrathecal morphine (ITM) on ventilatory function among MG patients undergoing tr ans-sternal thymectomy, when intravenous morphine served as control. M ethods: Twenty consecutive MG patients were randomised to receive eith er morphine (10 mu g/kg) intrathecally at induction or intravenous mor phine (30 mu g/kg) with a patient-controlled analgesia (PCA) device. A naesthesia was standardised. Forced vital capacity (FVC), forced expir atory volume in 1 s (FEV1), respiratory rate, oxygen saturation, arter ial blood gases, pain intensity and morphine consumption were assessed during 48 hours. Results: The mean age of the patients was 35+/-3.4 y ears and the mean duration of the disease 1.9+/-0.5 years. According t o Osserman's classification 70% of the patients belonged to Class IIA and 30% to Class IIB. ITM restored ventilatory function significantly better than iv PCA morphine. FVC recovered to 60% and FEV1 to 57% of t he baseline values in the ITM group compared with 32% (P<0.05) and 37% in the PCA morphine group, respectively. Postpuncture headache occurr ed in 4/10 patients. Conclusion: Intrathecal morphine provided effecti ve postoperative analgesia and significantly improved ventilatory func tion when compared with intravenous morphine. (C) Acta Anaesthesiologi ca Scandinavica 41 (1997).