Vital parameters. Systolic and diastolic blood pressure, the heart rate and saturation over time for the alfentanil and placebo group. * indicates a significant difference.Statistical differences were calculated between the reference measurement 1 ½ minutes after spasmolytic and 5/10 minutes after alfentanil injection. The heart rate was significantly higher after 5 minutes for both placebo and alfentanil group. No other significant differences were observed.