Nervous regulation of breathing in opiate dependent patient. Part I. Respiratory system efficiency and breathing regulation in the first stage of controlled abstinence.

Neurotoxic properties of opioid drugs which are the central nervous system depressant may have also depressive action on the brain stem complex responsible for the breathing control. Disorders of breathing regulation are reflected in respiratory efficiency. The aim of this study was to evaluate the regulation of breathing by measuring of respiratory pattern parameters, occlusion pressure and also to estimate the respiratory efficiency in opiate abusers. There were 76 persons under examination: group I--36 opiates abusers (29 men and 7 women; mean age 22.6 years) treated in the Detoxification Unit of the Department of Clinical Toxicology; group II (control group)--40 healthy persons (25 men and 15 women; mean age 28 years) not dependent of opiates and never treated at the Department. During hospitalisation the functional state of respiratory system was monitored. Ventilation efficiency was determined on the basic of the results from a "flow-volume" curve, spirometry and the measurements of the respiratory tract resistance in a computerised system Lungtest-MES company (Poland). Respiratory regulation was evaluated by means of synchronic measurements of the respiratory pattern (according to the assumption of Milic-Emili) and occlusion pressure P 0.1 (according to Whitlaw assumptions). In the examination performed directly after admission to the Unit the normal respiratory efficiency was noted in 24 persons. 12 persons (33.3%) suffered from the bronchi obturation. In the examination performed after hospitalisation and 9 days of total abstinence the normal ventilatory efficiency was found in 23 persons. In 13 of the patients (38.5%) respiratory obturation was still observed. After treatment in group of opiate abusers compared to control group values of respiratory resistance, occlusion pressure, minute ventilation and VT/T(in) index describing the activity of the central breathing regulation were increased, while the time of expiration and time of total breathing cycle were shorter.