Is a Low-Cost Home Pulse Oximeter Helpful in Blood Flow Restriction Training?

Confirm the validity of low-cost home pulse oximetry (POx) for determining arterial occlusion pressure (AOP) and compare blood flow (BF) responses to externally applied pressures.

Cross-sectional study.

Forty-two subjects were recruited. AOP was registered with POx and a high-resolution Doppler ultrasound. Peak (anterograde peak blood flow velocity and retrograde peak blood flow velocity) and mean blood velocity and BF were assessed in 5 different externally applied pressures: 0%, 25%, 50%, 75%, and 90% of AOP in upper and lower limbs.

Significant differences between POx and Doppler ultrasound were found (P < .001) in upper and lower limbs. In addition, the ability to identify AOP with POx was poor in both limbs (receiver operating characteristic curve: 0.644 and 0.477 in the upper and lower limbs, respectively). Moreover, BF in the upper limb decreased significantly in all conditions except 0% AOP (nonrestriction; P < .012); however, in the lower limb, BF decreased only in the 90% and 75% AOP condition (P = .010) compared with 0% AOP condition (P < .001). Thus, BF decreases in a nonlinear manner under relative externally applied pressures. Mean blood velocity decreased significantly in all conditions compared with 0% AOP (P < .05) in the upper limb, but in the lower limb, mean blood velocity was higher in the 90% AOP condition than in the 25% AOP condition (P = .008).

The results suggest that a low-cost home POx is not a useful device for estimating AOP. Furthermore, BF does not decrease linearly with the application of relative external pressure in the upper and lower limbs.