Guinard J P, Mulroy M F, Carpenter R L
Service d'Anesthésiologie, Clinique de Genolier, Switzerland.
Reg Anesth. 1995 May-Jun;20(3):193-8.
The authors recently determined that intravascular injection of an epinephrine test dose reliably produced an increase in heart rate > or = 20 beats/min in young individuals. However, aging is associated with a significant reduction in beta-adrenergic responsiveness. This study was designed to determine whether aging decreases the magnitude of heart rate (HR) increase after intravascular injection of epinephrine.
Heart rate and systolic blood pressure were recorded during randomized and double-blind injections of 3 mL lidocaine plain or lidocaine with 10 or 15 micrograms epinephrine in 30 elective surgical patients between 21 and 81 years old.
Increasing age was associated with smaller increases in HR after intravascular injection of epinephrine. The reduction in HR increase was statistically significant after 10 micrograms (P = .006, r2 = .24), but not after 15 micrograms (P = .25, r2 = .05) of epinephrine. Heart rate increases were of greater magnitude for patients younger than 40 years old (P = .01 for 10 micrograms epinephrine, and P = .03 for 15 micrograms epinephrine). One patient (of 11) over 60 did not respond to the 15 micrograms test dose with tachycardia. Aging did not alter systolic blood pressure increases after 10 or 15 micrograms epinephrine (P = .27, r2 = .04 and P = .4, r2 = .03, respectively).
Aging is associated with a reduction in the magnitude of HR increase after intravenous injection of epinephrine. The results suggest that to detect an intravascular injection in healthy people, a test dose containing 10 micrograms epinephrine will suffice before the age of 40. However, even 15 micrograms epinephrine will not be totally reliable in older patients, owing to decreased beta-adrenergic responsiveness.
作者最近确定，血管内注射肾上腺素试验剂量能使年轻人心率可靠地增加≥20次/分钟。然而，衰老与β-肾上腺素能反应性显著降低有关。本研究旨在确定衰老是否会降低血管内注射肾上腺素后心率（HR）增加的幅度。
在30例年龄在21至81岁之间的择期手术患者中，随机双盲注射3毫升单纯利多卡因或含10或15微克肾上腺素的利多卡因时，记录心率和收缩压。
血管内注射肾上腺素后，年龄增加与心率增加幅度减小有关。注射10微克肾上腺素后心率增加幅度的降低具有统计学意义（P = 0.006，r² = 0.24），但注射15微克肾上腺素后无统计学意义（P = 0.25，r² = 0.05）。40岁以下患者的心率增加幅度更大（注射10微克肾上腺素时P = 0.01，注射15微克肾上腺素时P = 0.03）。60岁以上的患者中有1例（共11例）对15微克试验剂量未出现心动过速反应。注射10或15微克肾上腺素后，衰老并未改变收缩压的升高幅度（分别为P = 0.27，r² = 0.04和P = 0.4，r² = 0.03）。
衰老与静脉注射肾上腺素后心率增加幅度降低有关。结果表明，为了在健康人群中检测血管内注射情况，40岁之前，含10微克肾上腺素的试验剂量就足够了。然而，由于β-肾上腺素能反应性降低，即使是15微克肾上腺素在老年患者中也并非完全可靠。
