Background and purpose: The study aimed to verify the efficacy and safety of morphine in the management of dyspnoea in patients with terminal amyotrophic lateral sclerosis (ALS). A further aim was to assess the effect of morphine on ventilation and the potential diminishing effect of nasal O(2)-insufflation preceding morphine administration on the intensity of dyspnoea.
Methods: Six dyspnoeic ALS patients were included in a prospective, non-randomized study. The intensity of dyspnoea was measured with a Numeric Rating Scale (NRS 0-10). Transcutaneous carbon dioxide partial pressure (tcpaCO(2)), oxygen saturation (SaO(2)) and pulse frequency were continuously monitored during the nasal insufflation of O(2) preceding the first morphine dose and also afterwards.
Results: A significant decrease was seen in both respiratory rate (from 42.0 +/- 6.0/min to 29.0 +/- 4.0) (P = 0.027) and the intensity of dyspnoea (from 7.5 +/- 1.9 to 1.8 +/- 0.8) (P = 0.027) 120 min after the morphine administration. Neither a significant tcpaCO(2) increase nor a SaO(2) decrease were seen. O(2)-insufflation did not significantly decrease the intensity of dyspnoea. The anxiety of choking correlated highly significantly with the intensity of dyspnoea (r = 0.861, P = 0.028) in all patients. There were no cases of respiratory depression.
Discussion: Therapeutic doses of morphine were effective and safe in the management of dyspnoea in ALS patients.