Pulmonary function and head lift during spontaneous recovery from pipecuronium neuromuscular block

We have studied in seven healthy conscious volunteers the correlation between the electro-myographic (EMG) and clinical criteria used to identify adequate recovery from sub-paralysing doses of pipecuronium. Pipecuronium (mean dose 1.88 (range 0.92–3.16) mg) was administered to reach a T4/T1 ratio of 0.5; full recovery to 1.0 was produced in a mean time of 25.3 (14–39) min. During recovery from neuromuscular block, we measured tidal volume, forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1) negative inspiratory pressure (NIP), peak expiratory flow rate (PEFR), mid-expiratory flow rate (MEFR) and 5-s head lift. The assessments were started when the train-of-four (TOF) ratio reached 0.5 ± 0.001 and repeated at each 0.1 ± 0.001 increase up to a ratio of 1.0. All volunteers showed ptosis and diplopia after the first dose and difficulty in swallowing with subsequent doses. They also experienced a pleasant, relaxing sedative sensation. All could sustain head lift for 5 s at a TOF ratio of 0.5 and higher, except for one subject who could not lift his head only at a ratio of 0.5. There was a statistically significant decrease in FVC, FEV, and PEFR with a nonsignificant decrease in other pulmonary measurements, except for NIP which only decreased significantly at a ratio of 0.5. These changes are probably of no clinical importance. All the measured respiratory variables returned to control values at a TOF ratio of 0.9. (Br.J. Anaesth. 1995; 74: 16–19)