Lidocaine and prilocaine with vasoconstrictors as cause for cardiovascular reactions. A pulse oximetric study. Preliminary report

Cardiovascular effects of two local anesthetic agent solutions containing 2% lidocaine with 1:80,000 epinephrine (LE) and 3% prilocaine with 0.54 microgram/ml felypressine (PF) used separately and in combination were observed. We made 38 separate monitoring sessions (30 minutes each) with healthy voluntary dental students. Participants were monitored with Cardiocap multiparameter physiological monitor. The monitored values were heart rate, systolic and diastolic blood pressure, SaO2 and peripheral blood flow. Values were registered into computer memory for further analysis. Group 1 received 7.2 ml of PF to the buccal sulcus just distal of the second upper right molar and 7.2 ml of LE to the left buccal sulcus ten minutes later. Group 2 had the same injection positions but they received 3.6 ml of PF to both sides of maxilla and then, ten minutes later, 3.6 ml of LE to each side.

There were no radical changes in systolic or diastolic blood pressure. The blood oxygen saturation values were constant and the displayed SaO2 values were between 96-98% during the measurement period. Mean heart rate decreased about 10 beats/min after PF injection and increased about 10 beats/min after injection of LE in both groups. The peripheral blood flow (pbf) was the most sensitive parameter in our measurements. In general, pbf diminished in the period preceding the injection. It showed lowest values during the injection phases in both groups.

Despite large doses of local anesthetics SaO2, systolic and diastolic blood pressure showed no clinically important changes, which suggests that local anesthetics have only a minimal effect on parameters mentioned above. This means that if the effect of one local anesthesia preparate (PF) is not sufficient, it is possible to safely reinforce the anesthesia with another substance (LE) in young healthy patients. Additionally, heart rate and pbf demonstrated quite clearly the symphatetic stimulation effect of the stress of injection and the stimulating action of epinephrine was seen clearly in heart rate values in both groups.