RESPIRATORY MECHANICS IN ANESTHETIZED PATIENTS AFTER NEOSTIGMINE-ATROPINE - A COMPARISON BETWEEN PATIENTS WITH AND WITHOUT CHRONIC OBSTRUCTIVE PULMONARY-DISEASE

The aim of this study was to compare the effects of pharmacological re versal of neuromuscular blockade on static compliance and resistance i n patients with and without chronic obstructive pulmonary disease (COP D). Twenty patients were studied: 12 patients were free of respiratory disease (NCOPD) and had normal pulmonary function tests. Eight subjec ts (COPD) had a clinical history of chronic bronchitis and a FEV1 <70% of the predicted value. All patients were anaesthetised with a contin uous infusion of methohexitone and alfentanil. Airway pressure (Paw) w as recorded continuously. Static compliance (Crs) was calculated from the relationship between 2 1 syringe volume (250 ml step) and Paw. Tot al respiratory resistance (Rrs) was measured at two levels of inspirat ory flow and tidal volume, These measurements were made before vecuron ium (control), after injection of vecuronium to abolish the first neur omuscular response to train of four, 5 and 15 min after administration of neostigmine 40 mug . kg-1 and atropine 10 mug . kg-1. In COPD pati ents Crs and Rrs were significantly greater (1450 +/- 580 ml . kPa-1 a nd 1.06 +/- 0.68 kPa . l-1 . s-1) than in normal patients (1000 +/- 38 0 ml . kPa-1 and 0.58 +/- 0.22 kPa . l-1 . s-1) (P<0.01). In both grou ps Crs and end-expiratory pulmonary volume were similar before injecti on of vecuronium and after neostigmine-atropine administration. In bot h groups, Rrs was not altered significantly by neostigmine-atropine fo r the two inspiratory flows. These results suggest that neostigmine-at ropine mixture is associated with small changes in respiratory mechani cs, and the changes are similar in COPD compared with normal patients.