Effect of pre-emptive analgesia on self-reported and biological measures of pain after tonsillectomy

This prospective, double-blind, randomized study assessed effect of pre-emp tive peritonsillar block in 30 ASA-I children, aged 6-12 years, of both sex es, scheduled for tonsillectomy. Patients were divided into three groups: t hose in group I received a sham block, whereas peritonsillar blocks with bu pivacaine 0.25% were given to the children before tonsillectomy (group II) or immediately after surgery had been completed (group III). Constant pain, pain on swallowing, blood glucose, serum epinephrine and norepinephrine co ncentrations were measured immediately after surgery and 4 h after operatio n. Patients in group experienced more pain (P < 0.05) than those in groups II and III, both in the immediate postoperative period and over the next 4 h. Patients in groups ii and III experienced similar pain (P > 0.05). The p ain experienced when water was swallowed was similar to that of the constan t pain. The rise of serum norepinephrine concentration in group II was sign ificantly less (Pe 0.05) compared to groups I and III. We found both pre-em ptive and postoperative block to be equally effective in treating postopera tive pain, with pre-emptive block being more effective in preventing the ri se in norepinephrine concentration.