Canadian journal of anaesthesia = Journal canadien d'anesthésie
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The effects of dobutamine on diaphragmatic contractility were studied in 24 dogs anaesthetized with secobarbital and receiving mechanical lung ventilation. The phrenic nerves were stimulated supramaximally for two seconds with electrodes placed around the fifth and sixth cervical roots when the airway was closed at the level of FRC. The stimulating frequency ranged from 10 to 100 Hz. ⋯ The Edi was not altered by dobutamine infusion. This enhancement of Pdi by dobutamine was abolished by simultaneous infusion of nicardipine, a Ca-channel blocker, but was not affected by prostaglandin E1. These results suggest that dobutamine has a stimulating effect on canine diaphragmatic contraction, and this action may be related to the increased inward movement of extracellular calcium.