Inverse correlation between seasonal changes in home blood pressure and atmospheric temperature in treated-hypertensive patients.

We examined the relationships between home blood pressure (BP) and atmospheric temperature in 20 treated-hypertensive patients. A significant correlation between morning and evening BP and atmospheric temperature was found. For morning systolic blood pressure (SBP), the maximal seasonal difference was 13.2 mmHg with 25.5 degrees C temperature difference. Morning SBP increased by approximately 0.41 mmHg with a 1 degrees C decrease in atmospheric temperature. A similar but weaker correlation with temperature was observed for morning diastolic, evening systolic and diastolic blood pressure (DBP). The present study provides important information in respect to BP changes with atmospheric temperature that should be taken into account in the analysis and treatment of hypertension.

Heart rate variability for evaluating surgical stress and development of postoperative complications.

Heart rate variability (HRV) has recently been used to detect autonomic nerve tone, which is affected by various stresses. To test out hypothesis that HRV can determine surgical stress, we examined perioperative HRV in 30 patients with surgical treatment. Relations between HRV and factors of surgical stresses, such as duration of the operation, amount of blood loss at the operation, and developments of complications, were evaluated. Mean heart rate (HR) increased and other HRV indices decreased postoperatively. Most indices correlated significantly to the duration of the operation and amount of blood loss at the operation on postoperative day 1. Only the standard deviation of normal to normal RR intervals (SDNN) and HRV triangular index showed significantly low values in complicated patients. HRV measurement in the perioperative period showed a significant relation to surgical stress. The present results indicated that HRV may provide useful information with respect to surgical stress.