Respiratory function in children during recovery from neuromuscular blockade

Residual neuromuscular blockade is a major risk factor for respiratory insufficiency. We examined the relationship between neuromuscular and respiratory function in 18 ASA I or II children aged 2-4 years. Lung function was measured by pneumotachography and transpulmonary pressure, neuromuscular transmission by first twitch response ratio (T1:T1) and train-of-four ratio (TOFR), before and at specific points in recovery from vecuronium paralysis. The tidal volume was directly related to maximal inspiratory pressure at occlusion (P I OCC), P<0.001, whereas the minute ventilation (V E ) was related to the respiratory drive (P0.1), P<0.001. The best predictors of minute ventilation were the P0.1 (r=0.57), and the TOFR (r=0.62). P 1 OCC and P0.1 correlated closely (r=0.889, P=0.002) but TOFR and T1:T1 did not correlate with either. Our results show that the occlusion pressure measurements, P0.1 and P I OCC, were good predictors of both V E .kg -1 and respiratory work.