Summary The American Society of Anesthesiologists (ASA) physical status is a tool commonly used to classify a patient's physical fitness before surgery. Since its introduction in 1941 it has undergone very few modifications to improve its reliability and to eliminate subjectivity, despite vast changes in both surgical and anaesthetic technique. We present the history of the ASA physical status and review the literature on its applicability to contemporary anaesthetic practice.

European Society of Anaesthesiology.

We have studied the pharmacokinetics of a single bolus dose of tramadol 2 mg kg-1 injected either i.v. or into the caudal epidural space in 14 healthy children, aged 1-12 yr, undergoing elective limb, urogenital or thoracic surgery. Serum concentrations of tramadol and its metabolite O-demethyl tramadol (MI) were measured in venous blood samples at various intervals up to 20 h by non-stereoselective gas chromatography with nitrogen-selective detection. All pharmacokinetic variables were evaluated using a non-compartmental model. After a single i.v. injection (n = 9), the mean elimination half-life of tramadol was 6.4 (SD 2.7) h, with a volume of distribution of 3.1 (1.1) litre kg-1 and total plasma clearance of 6.1 (2.5) ml kg-1 min-1. All of these pharmacokinetic variables were similar to those reported previously in adults. After caudal epidural administration (n = 5), mean elimination half-life was 3.7 (0.9) h, volume of distribution was 2.0 (0.4) litre kg-1 and total clearance was 6.6 (1.9) ml kg-1 min-1. The caudal/i.v. quotient of the AUC was 0.83, which confirms that there is extensive systemic absorption of tramadol after caudal administration. Serum concentrations of MI showed a time course typical of a metabolite after both modes of administration. Serum concentrations of MI after caudal administration were lower than those after i.v. injection.

Short postoperative stay after hip arthroplasty can be achieved without intensive patient preparation or post-discharge care and without compromising short-term patient outcome or increasing health care costs. Longer term follow-up is needed.