CARDIOVASCULAR EFFECTS OF AN INTUBATING DOSE OF ROCURONIUM 0.6 MG KG(-1) IN ANESTHETIZED PATIENTS, PARALYZED WITH VECURONIUM

We have studied, in adult patients, ASA I-II, the cardiovascular effec ts of an intubating dose of rocuronium 0.6 mg kg(-1). After induction, patients were paralysed with vecuronium and the trachea intubated. He art rate (HR) and non-invasive mean arterial pressure (MAP) were measu red every 1 min. After stabilization of HR and MAP, defined as <3% cha nge over three measurements, rocuronium (n=20) or saline (n=10) was in jected at random. Mean HR increased initially from 66.6 to 72.1 beat m in(-1), 4 min after rocuronium, and then decreased gradually to 69.6 b eat min(-1), that is a net increase of 3.3 beat min(-1) over 10 min (P <0.001), whereas after saline there was a gradual decrease from 65.8 t o 60.9 beat min(-1) (P<0.001) over 10 min. From the third minute, HR w as significantly higher in the rocuronium group. Mean MAP decreased in both groups within 10 min to a similar extent after rocuronium and sa line, that is from 74.9 to 72.1 mm Hg and from 74.7 to 72.2 mm Hg, res pectively (both P<0.001). There were no differences in MAP at any time between the rocuronium and saline groups. We conclude that an intubat ing dose of rocuronium, in the absence of haemodynamic effects related to paralysis itself, resulted in a limited increase in HR without cha nge in MAP, probably because of its weak vagolytic activity.