Cardiovascular parameters and liver blood flow after infusion of a colloid solution and epidural administration of ropivacaine 0.75%: the influence of age and level of analgesia

BACKGROUND AND OBJECTIVE: Lumbar epidural anaesthesia induces cardiovascular changes and decreases liver blood flow (Qh). We studied the effects of age on haemodynamics, blood volumes and Qh before and after epidural anaesthesia. METHODS: Thirty-six patients were enrolled as follows: group 1, 20-44 years; group 2, 45-70 years; group 3, >70 years. Using pulse dye densitometry, in addition to heart rate and arterial blood pressure (arterial BP), cardiac output, total blood volume, central blood volume and Qh were measured, before and after colloid infusion (500 ml hydroxyethyl starch, 6%) and after epidural administration of 15 ml of 0.75% ropivacaine. RESULTS: With age the level of analgesia [median (range)] increased from T7 (L2-T4) in group 1 to T4 (T10-C7) in group 3 (P = 0.04). After colloid infusion, heart rate (mean difference +/- SE; 2.1 +/- 0.7 beats min(-1)), systolic BP (4.1 +/- 2.2 mmHg) and Qh 162 ml min(-1) (ratio 0.90, 95% confidence interval 0.81-0.99) increased slightly but significantly, and were unaffected by age. Epidural anaesthesia induced a significant decrease in Qh (265 ml min(-1); ratio 1.20, 95% confidence interval 1.07-1.35) and arterial pressure (for systolic BP: P = 1 x 10(-7)). A significantly larger decrease in systolic BP occurred in the older, compared with the middle, age group (P = 0.04). Age did not affect epidural-induced changes in cardiac output, total and central blood volumes, and Qh. CONCLUSION: Age increases the level of analgesia after epidural ropivacaine and is associated with a more pronounced decrease in arterial pressure. A colloid preload mildly increases haemodynamics, but this insufficiently prevents younger and elderly patients from a decrease in Qh after lumbar epidural anaesthesia.