Neuromuscular blockade provides no benefit over adequate sedation in ventilated dogs.

PURPOSE

To investigate the effect of pharmacological paralysis on systemic oxygen consumption to determine whether pharmacological paralysis offers a physiological benefit over adequate sedation in ventilated animals.

METHODS

Nine dogs with normal pulmonary function were mechanically ventilated and sedated with alpha-chloralose while paralysis was induced with vecuronium. Oxygen consumption was determined via indirect calorimeter in each animal repeatedly in the presence or absence of paralysis with seven paired observations in each animal. Sixty-three pairs of data from nine animals were analyzed by analysis of variance with correction for multiple comparisons.

RESULTS

Oxygen consumption was 4.3% higher in the unblocked state compared with the blocked state (5.39 +/- 0.32 v 5.16 +/- 0.34 mL/kg-min, P < .001). Carbon dioxide production was 3.0% higher in the unblocked state compared with the blocked state (4.92 +/- 0.24 v 4.77 +/- 0.23 mL/kg-min, P < .01). No other physiological effects were noted.

CONCLUSIONS

Pharmacological paralysis of mechanically ventilated animals with normal pulmonary function that are sedated and resting comfortably produces a statistically significant reduction in oxygen consumption; however, the magnitude of this change is so small that little genuine clinical benefit would be anticipated.