Pulmonary Doppler flow velocity pattern during caudal epidural anaesthesia in children

Haemodynamic effects of caudal anaesthesia in children have not been fully investigated. In the present study, we evaluated pulmonary haemodynamics during caudal anaesthesia in otherwise healthy children using Doppler-echocardiography.

Fifteen children undergoing elective lower abdominal surgery were randomly divided into two groups: nine children received 1.5% lidocaine and six physiological saline in the caudal epidural space. General anaesthesia was slowly induced and maintained using nitrous oxide and sevoflurane in oxygen. An epidural catheter was inserted into the caudal epidural space. Haemodynamic data including those with echocardiography were measured before and after epidural administration of lidocaine or saline.

Mean blood pressure, end diastolic diameter of the left ventricle, ejection fraction of the left ventricle and mean velocity circumferential fibre shortening did not change in either group following caudal epidural block. Indices of pulmonary Doppler flow velocity, including peak velocity of pulmonary flow and acceleration-to-ejection time ratio, demonstrated a significant decrease after caudal lidocaine, but not after saline.

Our data suggest that pulmonary Doppler flow velocity changes during caudal epidural anaesthesia, probably due to an increase in the pulmonary arterial resistance.