Neuropeptide Y response to tracheal intubation in anaesthetized children: effects of clonidine vs midazolam as premedication

We have determined if tracheal intubation causes an increase in neuropeptid e Y (NPY), a marker of major adrenergic activation, and investigated if rec tal premedication with clonidine 2.5 mu g kg(-1) might be capable of attenu ating the stress response to tracheal intubation compared with midazolam 30 0 mu g kg(-1), in 20 paediatric patients (1-9 yr). Prospective randomizatio n was performed in a double-blind manner. After induction of anaesthesia wi th 1% isoflurane, tracheal intubation was performed, and norepinephrine, NP Y concentrations and haemodynamic variables were recorded. Tracheal intubat ion did not increase NPY plasma concentrations, despite transient increases in norepinephrine concentrations, heart rate and arterial pressure. There was no significant difference between the two groups. We conclude that the adrenergic stress reaction in response to tracheal intubation in children w as short-lived and of limited magnitude, as indicated by the lack of NPY re lease.