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Backpack straps decrease upper extremity blood flow
Author(s) -
Neuschwander Timothy,
Macias Brandon,
Hargens Alan
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.957.28
Subject(s) - medicine , backpack , blood flow , brachial artery , artery , anesthesia , surgery , cardiology , blood pressure , archaeology , history
Adults in professions such as the military, firefighting, and mountain rescue routinely carry packs loaded with 60% body weight. Backpack straps are typically situated in a region where they may compress the axillary vein, causing venous hypertension and subsequently decreasing upper extremity blood flow. We hypothesize that upper extremity macro and microvascular blood flow will decrease while wearing a loaded backpack. Eight healthy volunteers (6 men, 2 women, age range: 18 – 30 years) had the right brachial artery measured with ultrasound Doppler. Index finger pulp microvascular flow was measured using photoplethysmography. Baseline flows were measured immediately before and 10 min after donning a 12kg backpack. Baseline microvascular flow was normalized to 100%; data are presented as means±SE. After wearing the pack for 10 min, brachial artery blood flow decreased from 2.66±0.36 to 1.52±0.27 mL/s (p<0.05, paired T‐test), and index finger microvascular flow decreased from 100% to 46±6% (p<0.05, paired T‐test). Even light backpack loads such as 12kg decrease upper extremity macrovascular and microvascular blood flows and may result in a loss of fine motor control and increased fatigue. Redesigning backpack straps to prevent compression of the axillary vein about the clavicle may maintain normal blood flow. Supported by UCSD Dept. of Orthopaedic Surgery Discretionary Funds.