歯科診療時の患者体位に関する研究 循環器系への影響

Abstract

This study was designed to examine the influence of posture on dental stress.The subjects were seventeen healthy male volunteers who were divided into two groups: ten subjects aged 22-29 years (‘young’ group) and seven aged 45-69 years (‘old’ group). Four measurements were performed, in the supine (0°C), semi-supine (45°C) and sitting (85°C) positions. Dental stress was induced by injecting 2 ml of saline into the upper incisal gingiva over two minutes ; blood pressure, heart rate and systolic time intervals were measured before injection as control values, during injection, and 1, 3, 5, 10 and 20 minutes after injection. The concentration of plasma catecholamines was also measured by the HPLC-ECD method.The results are as follows.1. Before injection higher value of plasma norepinephrine (55.6% in higher ‘young’ group, 77.6% in higher ‘old’ group) was recognized in the sitting position as compared with the supine position, and higher value of pre-ejection phase (PEP)/left ventricular ejection time (LVET)(45.2% in higher ‘young’ group, 38.6% in higher ‘old’ group) was recognized. The more upright posture, the less left ventricular ejection time index (LVETI) was recognized.2. After injection the concentration of plasma norepinephrine increased in the sitting position (65.2% in ‘young’ group, 103.4% in ‘old’ group). Increase of PEP and PEP/LVET was recognized in each position.3. In ‘old’ group individual variation of the concentration of plasma catecholamines was remarkable. Increase of PEP and PEP/LVET after injection was greater and the recovery time was longer.In the sitting position the acceleration of sympatico adrenomedullar system and the inhibition of myocardial contractility due to low preload was recognized before injection. In the sitting position the more myocardial contractility inhibition due to increase of afterload was recognized after injection. In ‘old’ group the capacity of myocardial contractility was considered to be low.Therefore posture during dental treatment is important for prevention of shock, and, the supine position is the most effective especially for older patients.