Anatomical Determinants of Forearm

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Anatomical Determinants of Forearm Upper Arm
OscillometricBlood Pressure Differences

• Kathleen Schell, PhD, RN, Associate Professor,
  Nursing
• William Rose, PhD, Assistant Professor, Health
  Exercise Science
• In Collaboration with Angela Di Sabatino, RN, MS
  Cardiovascular Clinical Trials Program, CCHS

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Background Significance

• Accurate BP measurement is essential to providing
  appropriate healthcare.
• Increased use of forearm BP when upper arm
  inaccessible or when available cuff does not fit.
• Past research demonstrates that forearm and upper
  arm automatic BPs differ for many individuals.
  Size of differences varies.
• Unclear what factors influence the differences.

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Aims

• Aim 1 Compare forearm and upper arm automatic
  BPs and central arterial pressure in adults
  undergoing non-emergent cardiac catheterization
  or coronary intervention.
• Hypothesis 1A Upper arm BP will be within 5 mm
  Hg of central arterial pressure.
• Hypothesis 1B Forearm BP will be within 10 mm
  Hg of central arterial pressure.
• Hypothesis 1C Forearm BP will be within 5 mm
  Hg of corresponding upper arm BP.

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Aims

• Aim 2 Determine effects of anatomical structures
  on differences in forearm and upper arm automatic
  BPs in adults undergoing non-emergent cardiac
  catheterization or coronary intervention.
• Hypothesis 2 Body mass index, arm circumference,
  biceps skin-fold measurement, vessel diameter,
  and vessel depth will predict the differences
  between forearm and upper arm automatic BP
  readings.

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Aims

• Aim 3 Compare central aortic pressure waveform
  with brachial and radial pressure waveforms and
  with waveform predicted by a computer model.
• Hypothesis 3 A quantitative model of pressure
  wave propagation and reflection will predict the
  differences between central aortic, brachial, and
  radial pressure waveforms.

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Subject Eligibility Convenience Sample

• Inclusion Criteria
• Able to read and speak English or Spanish
  (consent will be translated into Spanish)
• Age 18 years
• Exclusion Criteria
• Non-intact skin where BP cuffs would be placed
• Arm injury or surgery within the last month
• Atrial fibrillation or atrial flutter (as
  recommended by BP device manufacturers due to
  device inaccuracy)
• International Normalized Ratio (INR) gt 1.7
• Intravenous catheters in both arms
• Hemodynamic instability or need for immediate
  cardiac surgery or emergency treatment

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Procedure

• In the Cardiac Intervention Room
• BP cuffs placed on right forearm and upper arm
  prior to draping of patient
• Obtain simultaneous central aortic pressure
  waveform and forearm and upper arm cuff BP
  measurements X 2
• Radial and brachial artery tonometry
• Data collection via laptop computer
• Remove cuffs after cardiac procedure completed
• Cart with Dinamap ProCare and laptop computer
  positioned on right side of patient, away from
  table, superior and to the right of patients head

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Tonometry

• Tonometry
• Position tonometry probe on radial artery
  measure waveform for 20 seconds
• Repeat with brachial artery

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Data Collection Timeline

• Time (minutes)

Ao Central aortic blood pressure via catheter
UAC, FAC Upper arm cuff pressure, forearm cuff
pressure
RT, BT Radial artery tonometry, brachial artery
tonometry
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FUNDING

• University of Delaware
• Research Foundation Grant