摘要
目的:传统的上肢平均动脉压计算是以1/3脉压加舒张压。作者对该公式的普通适用性提出质疑。方法:使用57例受试者先前记录的静息肱动脉内压和Riva-Rocci Korotkoff血压(研究A)以及22例非卧床受试者的24h动脉内压记录(研究B)进行评估。结果:研究A中,所有受试者动脉内测量的"真正"平均压为舒张压加上39.5%±2.5%的脉压,即水平高于预期的33.3%脉压。该结果与年龄、血压、脉压或心率均无关。因此,当根据动脉内压读数计算时,采用传统的1/3法计算的平均压低估了"真正"平均压5.0±2.3mm H g(P【
OBJECTIVES: Mean arterial pressure at the upper arm is traditionally calculated by adding one-third of the pulse pressure to the diastolic pressure. We questioned the general validity of this formula. METHODS: We used previously recorded resting intrabrachial pressure and Riva-Rocci Korotkoff blood pressure measurements in 57 subjects(study A) and 24-h intraarterial recordings obtained in 22 ambulant subjects(study B). RESULTS: In study A the intra-arterially measured ‘ real’ mean pressure was found at 39.5± 2.5% of pulse pressure above diastolic pressure, namely at a level higher than the expected 33.3% of pulse pressure, in all individuals. Results were not related to age, blood pressure, pulse pressure or heart rate levels. Mean pressure calculated with the traditional one-third rule therefore underestimated ‘ real’ mean pressure by 5.0± 2.3 mmHg(P< 0.01) when calculated from intra-arterial pressure readings, and by 4.9± 5.3 mmHg(P< 0.01) when calculated from Riva-Rocci Korotkoff readings. In study B we showed activity-related variations in the relative level of the ‘ real’ mean pressure, which increased by 1.8± 1.4% (P< 0.01) during sleep, and decreased by 0.5± 0.9% during walking(P< 0.05) and by 0.8± 1.3% during cycling(P< 0.01). CONCLUSION: The mean pressure at the upper arm is underestimated when calculated using the traditional formula of adding one-third of the pulse pressure to the diastolic pressure. This underestimation can be avoided by adding 40% of pulse pressure to the diastolic pressure. The proposed approach needs to be validated through larger scale studies.
