Limited maximal flow rate of target-controlled remifentanil infusion and induced cough.

This study evaluated the effect of limiting maximal infusion-pump flow rate on suppression of remifentanil-induced cough during target-controlled infusion. Two hundred and ten patients were randomly assigned to receive remifentanil at an effect-site concentration of 4.0 ng. ml) 1 with maximal flow rate limited to 100 (group R100), 200 (group R200), or 1200 ml. h) 1 (group R1200). The number of episodes of cough were recorded and graded as mild (1-2), moderate (3-4), or severe (5 or more). The incidence of cough was 2.9% in group R100, 5.7% in group R200 and 25.7% in group R1200. Patients in group R100 and R200 had a significantly lower incidence of cough than those in group R1200 (p < 0.05). Zero, two and five patients coughed a moderate amount in groups R100, R200 and group R1200, respectively (p < 0.05). Limiting maximal infusion rate during remifentanil TCI suppressed remifentanil-induced cough.