Changes in blood pressure and heart rate variability during dental surgery.

The objective of the present study was to determine the changes in blood pressure, pulse rate, and heart rate variability during dental surgery. The study included 40 patients, 19 to 74 years of age (mean age: 42.7+/-3.0 years), who underwent tooth extraction at our hospital. Holter electrocardiographic monitoring was used to determine the power spectrum of R-R variability before and during dental surgery. The low frequency (LF: 0.041 to 0.140 Hz), high frequency (HF: 0.140 to 0.500 Hz), and total spectral powers (TF; 0.000 to 4.000 Hz) were calculated, and the ratio of LF to HF and percentage of HF relative to TF (%HF: HF/TF x 100) were used as indices of sympathetic and parasympathetic activities, respectively. The baseline blood pressure and pulse rate were 121+/-3/70+/-2 mm Hg and 70+/-1 beats/min, respectively. After the administration of local anesthetic (2% lidocaine) containing 1:80,000 epinephrine, both the blood pressure and pulse rate increased. During dental surgery, blood pressure increased further to 132+/-3/73+/-2 mm Hg. The increase in blood pressure was greater in middle-aged and older patients (> or =40 years old). In young patients (<40 years old), the %HF decreased and the LF/HF increased during local anesthesia. In contrast, in middle-aged and older patients, the LF/HF decreased during local anesthesia. These results suggest 1) that middle-aged and older patients have a greater increase in blood pressure during dental surgery than younger patients, and 2) that the regulation of the autonomic nervous system during dental surgery differs between younger and older patients.