Ragab Suzanne, Lunt Michael, Birch Anthony, Thomas Peter, Jenkinson Damian F
Poole Hospital NHS Trust, Elderly Medicine, Poole, Dorset, UK.
Age Ageing. 2004 May;33(3):299-303. doi: 10.1093/ageing/afh091.
Caffeine is present in a variety of beverages and food and is widely consumed. In a previous study of patients recovering from an acute ischaemic stroke using transcranial Doppler ultrasound we demonstrated a fall in middle cerebral artery blood velocity of 12% following ingestion of 250 mg caffeine. The aim of this study was to investigate if this velocity change reflected a change in cerebral blood flow.
The study used a randomised, double blind, cross-over design. Nineteen patients recovering from an acute ischaemic stroke in the middle cerebral artery territory and 10 controls attended two sessions, having abstained from caffeine for 48 hours previously. At each session cerebral blood flow was measured four times using xenon clearance, twice before the oral administration of 250 mg caffeine or matched placebo, and twice after. Similarly, three middle cerebral artery blood velocity readings using transcranial Doppler were made prior to administration and four after.
The caffeine resulted in a significant fall in cerebral blood flow and middle cerebral artery blood velocity compared to placebo.
Since caffeine is present in the diet of most patients recovering from an acute ischaemic stroke this effect may have adverse clinical consequences.
咖啡因存在于多种饮料和食物中，被广泛食用。在之前一项对急性缺血性中风康复患者使用经颅多普勒超声的研究中，我们发现摄入250毫克咖啡因后大脑中动脉血流速度下降了12%。本研究的目的是调查这种速度变化是否反映了脑血流量的变化。
本研究采用随机、双盲、交叉设计。19名大脑中动脉区域急性缺血性中风康复患者和10名对照者参加了两个阶段的研究，此前已禁食咖啡因48小时。在每个阶段，使用氙清除法测量脑血流量4次，在口服250毫克咖啡因或匹配的安慰剂之前测量两次，之后测量两次。同样，在给药前使用经颅多普勒进行三次大脑中动脉血流速度读数，给药后进行四次。
与安慰剂相比，咖啡因导致脑血流量和大脑中动脉血流速度显著下降。
由于大多数急性缺血性中风康复患者的饮食中都含有咖啡因，这种影响可能会产生不良临床后果。
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