Analysis of Red Blood Cell Concentration in the Digits of the Hand of Controls and Participants with Carpal Tunnel Syndrome: A Response to Cold Temperature

Background Impaired microcirculation in response to cold is a feature of multiple hand disorders. This study aimed to quantify red blood cell concentration changes in the digits of the hands of controls and carpal tunnel syndrome patients after cold exposure. Methods Patients with CTS (n = 7) and controls (n = 27) were tested in a pre-test-post-test design. Superficial microcirculation of distal palmar area of the digits of the hand was quantified using the TiVi600 Polarization Spectroscopy Camera, which photographed participants' hands for 12 minutes. At two minutes, photography was paused as participants underwent the Ice Immersion Test (ICE). Photographs resumed post-ICE for 10 minutes. Analysis of variance was conducted to determine differences in blood flow, pain perception, and temperature recovery. Results Statistically significant increases in blood flow were observed immediately post-ICE in controls (dominant hand µ_{blood flow pre-ICE} = 274.69AU σ = 47.22, µ_{blood flow post-ICE} = 305.97AU σ = 67.13; nondominant hand µ_{blood flow pre-ICE} = 286.34AU σ =65.22, µ_{blood flow post-ICE} = 321.83AU σ = 76.78), and in nondominant hands of CTS participants (µ_{blood flow post-ICE} = 266.00AU σ = 49.72, µ_{blood flow post-ICE} = 323.93AU σ = 37.01). The CTS participants consistently reported their pain as being lower than controls, and all participants recovered to baseline temperatures post-ICE. Conclusions Research on blood flow response to prolonged cold temperatures is needed to inform longer-term responses. This study identifies potential for future research on using cold water immersion as a therapeutic cooling intervention.