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Study Title and Description

Influences of caffeine, acetazolamide and cognitive stimulation on cerebral blood flow velocities.



Key Questions Addressed
1 For [population], is caffeine intake above [exposure dose], compared to intakes [exposure dose] or less, associated with adverse effects on cardiovascular outcomes?
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Primary Publication Information
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TitleData
Title Influences of caffeine, acetazolamide and cognitive stimulation on cerebral blood flow velocities.
Author CG Haase,M Becka,J Kuhlmann,G Wensing,
Country
Year 2005
Numbers

Secondary Publication Information
There are currently no secondary publications defined for this study.


Extraction Form: Cardiovascular Design
Design Details
Question... Follow Up Answer Follow-up Answer
What outcome is being evaluated in this paper? Cardiovascular
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What is the objective of the study (as reported by the authors)? In order to assess the influence of caffeine and AA on cognition as well as on cerebral blood flow velocities, we examined healthy male volunteers at rest and during psychometric testing under the influence of either caffeine, acetazolamide and placebo in a double-blind, double dummy cross-over design.
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Provide a general description of the methods as reported by the authors. Information should be extracted based on relevance to the SR (i.e., caffeine related methods) A total of 18 right-handed male healthy subjects participated in this study. Mean age was 31.6 +/- 6.0 years, with a range of 21–41 years and a mean weight of 83.7 +/- 8.2 kg. Exclusion criteria included multiple lifestyle medical history, and physiological factors, including use of caffeine-containing beverages 24 h before the study day; caffeine-containing forms exceeding a daily consumption of 7 cups/day (3 mg/kg body weight). The study was conducted under fasting condition. Heart rate, and respiratory rates were measured continuously, blood pressures were recorded in parallel to TCD measurements and up to 4 h after administration of the study drugs. Study periods of this cross-over study were performed at least 1 week apart to avoid carry-over effects. In order to ensure subject’s compliance to remain abstinent to caffeine for ca. 24 h before the study, plasma samples for the measurement of caffeine concentrations were taken at the morning of the study day at each of the periods and 4 h after study drug administration. Analyses were performed using a sensitive enzyme immunoassay technique. Sequence of Measurements Subjects were randomized to the different treatment groups and evaluated for safety (EKG, clinical chemistry, hematology). After they had been cognitively trained, by repeating the cognitive test for three times, two 2-mHz-transcranial Doppler ultrasound (TCD)-probes were fixed bilaterally to the temples. Signals of middle cerebral arteries (MCA) were detected at depth of around 50 mm and continuos recording of Doppler wave spectra was performed and stored on hard disk of a MultiDopT (DWL, Sipplingen). After baseline values (t0 min) had been recorded, study medication was administered in a double-blind design. All subjects received as orange juice with or without (placebo) one resolved 200 mg tablet of caffeine (Merck KGaA, Darmstadt). 30 min later (t30 min), TCD continuous measurements were recorded and analyzed at t32 and t34 min during the verbal memory test and at t40 min, after finalization of the test. Adverse events, vital signs, ECG, laboratory, parameters, physical examination, and subjective well being as well as plasma caffeine measurements were assessed up to 4 h after the last administration of the study medications. Statistical Analysis Electronically transferred TCD data and differences to baseline were summarized by treatments using arithmetic mean, standard deviation. "Stimulated" was defined by the mean of observations at minutes 32, 34. "Unstimulated" was defined by the observations at 30 and 40 min. Differences between treatment groups were analyzed using Student’s paired t -test, significance was set at p < 0.05.
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How many outcome-specific endpoints are evaluated? 3
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What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) Blood pressure (SBP, DBP)
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List additional health endpoints (separately). 2 Heart rate
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List additional health endpoints (separately).3 Cerebral blood flow velocities (CBFV; reported as Vmean and Vmin)
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List additional health endpoints (separately).4
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List additional health endpoints (separately).5
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List additional health endpoints (separately).6
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Clinical, physiological, other Physiological
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What is the study design? Controlled Trial
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Randomized or Non-Randomized? RCT
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What were the diagnostics or methods used to measure the outcome? Objective
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Optional: Name of Method or short description EKG using two 2-mHz-transcranial Doppler ultrasound (TCD)-probes fixed bilaterally to temples
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Caffeine (general) Caffeine (general)
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Coffee, Chocolate, energy drink, gum, medicine/supplement, soda, tea, other?
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Measured or self reported? Measured
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Children, adolescents, adults, or pregnant included? Adults
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What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.) Subjects served as their own controls
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What were the listed confounders or modifying factors as stated by the authors? (e.g. multi-variable components of models.  Copy from methods) None
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What conflicts of interest were reported? The authors would like to thank U. Artmeier-Brandt, MD for technical support and disclose any commercial and other associations that might pose a conflict of interest in connection with the submitted material.
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Refid 15866357
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What were the sources of funding? No information provided
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Results & Comparisons

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