The effect of intratracheal and intravenous lidocaine in hydrochloric acid-induced acute lung injury in rabbits

The aim of this study was to show the effect of intratracheal (IT) and intravenous (IV) lidocaine on haemodynamic and arterial blood gas values in hydrochloric acid (HCl) induced-acute lung injury (ALI) in rabbits.

Twenty New Zealand rabbits were randomly divided into for groups of five. An endotracheal tube was placed through a tracheostomy in all animals following ketamine hydrochloride (50 mg/kg, intramuscularly) induced anaesthesia. Maintenance of anaesthesia was achieved by the use of ketamine hydrochloride 10 mg/kg/h and atracurium besylate 1 mg/kg/h. The animals were ventilated with Pressure Control mod for 3 hours and the parameters of ventilation were FiO₂: 1.0, RR: 80/min, Vt: 8 ml/kg, I/E: 1/2, PEEP: 5 cmH₂O. Intratracheal HCl (2 ml/kg), was given following tracheostomy in all animals. Five minutes after the application of HCl the group 1 received IV lidocaine (2 mg/kg), group 2 received IT lidocaine (2 mg/kg), group 3 received IV lidocaine (4 mg/kg) and group 4 received IT lido-caine (4 mg/kg). We recorded mean arterial blood pressures (MAP), heart rate (HR) every 60 min. We measured arterial blood gas values (PaO₂, PaCO₂, pH) at beginning of the study, at 90th and 180th minutes. Data were compared by Mann–Whitney U-test. A P value of less than 0.05 was considered to indicate statistical significance.

MAP levels of group 2 and group 4 were higher than group 1 and group 3 at 120th and 180th minutes (P < 0.05). HR levels of group 2 were lower than the other groups at 120th and 180th minutes (P < 0.05). PaO₂ levels of group 1 were higher than the other groups at 180th minute (P < 0.001). There was no significant difference between four groups regarding PaCO₂, pH.

In conclusion, IT and IV lidocaine (2 mg/kg) given after 5 min of HCl application had a beneficial effect on the haemodynamic and arterial blood gas values in acute lung injury in rabbits model.