Plasma catecholamine and haemodynamic responses to surgical endodontic anaesthetic protocols

The effects of varying clinically relevant patterns of anaesthetic-vasoconstrictor combinations used for peri-radicular surgery on plasma concentrations of catecholamines and haemodynamic responses was studied in the canine model. Five mongrel dogs were anaesthetized with sodium pentobarbital. A femoral canula was inserted to measure central blood pressure and an ECG was used to monitor heart rate and any associated arrhythmias. Femoral venous blood samples were drawn before initial injection and at 3 and 10 min after injections. Plasma catecholamine concentrations were determined using high pressure liquid chromatography (HPLC). Injection protocols used three time periods, 30, 60 and 90s, with solutions containing 1:100000 and 1:50000 adrenaline. No significant changes in heart rates or presence of arrythymias were noted over the experimental protocol. Catecholamine levels in pico moles mL^-1 were within the normal range at the 3-min sample level. At the 10-min sample time there was a more erratic range of concentrations, with most samples within the normal range. This may have been due to endogenous release of catecholamines in specific animals. The data identified trends in both the haemodynamic parameters and plasma catecholamine levels that can legitimately support the careful use of higher levels of a vasoconstrictor when patient profiles and surgical needs dictate.