Efficacy of lignocaine in the suppression of the intra-ocular pressure response to suxamethonium and tracheal intubation.

The effect of lignocaine pretreatment on the intra-ocular pressure response to suxamethonium and tracheal intubation was studied in 80 adult patients, divided randomly into four groups of 20 each. These groups received respectively normal saline (10 ml), lignocaine 1 mg/kg, 1.5 mg/kg and 2 mg/kg as pretreatment, in a double blind manner, one minute before anaesthetic induction with thiopentone and suxamethonium 1.5 mg/kg. Lignocaine pretreatment caused a significant decrease in intra-ocular pressure. Suxamethonium caused a significant increase, but lignocaine pretreatment in doses of 1.5 mg/kg and 2 mg/kg effectively kept the postsuxamethonium pressure below control values. Tracheal intubation further aggravated the postsuxamethonium increase in intra-ocular pressure. Lignocaine, in doses of 1.5 mg/g and 2 mg/kg also effectively kept the postintubation pressure values below control levels. Lignocaine, in dose of 1 mg/kg, only partially attenuated the postsuxamethonium and postintubation increase in intra-ocular pressure. In conclusion, lignocaine pretreatment, in a dose of 1.5 mg/kg, offers protection against suxamethonium- and tracheal-intubation initiated increases in intra-ocular pressure, without causing any significant decrease in arterial pressure.