title: Subcutaneous and Intramuscular Hemodynamics and Oxygenation After Cold-Spray Application as Monitored by Near-Infrared Spectroscopy.
abstract: BACKGROUND
  Vapocoolant spray, commonly known as cold spray (CS), is a cryotherapy modality used in sports medicine, athletic training, and rehabilitation settings. Proposed physiologic effects of cryotherapy modalities include reductions in tissue blood flow, oxygenation, and cell metabolism in addition to attenuation of pain perception attributed to reduced superficial nerve conduction velocity.
  
  
  OBJECTIVE
  To examine the effects of CS on subcutaneous and intramuscular blood flow and oxygenation on the thigh muscle using near-infrared spectroscopy, an optical method to monitor changes in tissue oxygenated (O2Hb), deoxygenated (HHb), and total (tHb) hemoglobin.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Muscle Biophysics Laboratory.
  
  
  METHODS
  Participants were 13 healthy adults (8 men, 5 women; age = 37.4 ± 6 years, body mass index = 27.4 ± 2.6, adipose tissue thickness = 7.2 ± 1.8 mm).
  
  
  METHODS
  Conventional CS was applied to the vastus medialis muscles.
  
  
  METHODS
  Changes in chromophore concentrations of O2Hb, HHb, and tHb at superficial and deep layers were monitored for 5 minutes using a 2-channel near-infrared spectroscopy.
  
  
  RESULTS
  Thirty seconds after CS application, we observed a decrease from baseline in O2Hb and tHb only in the superficial layer that was maintained for 3 minutes.
  
  
  CONCLUSIONS
  Application of CS induced a transient change in blood flow and oxygenation of the superficial tissues with no change in deeper tissues over the healthy vastus medialis muscle. The limited physiologic effect of CS on the superficial hemodynamics and oxygenation of limb muscles may limit the therapeutic benefit of this cryotherapy modality to a temporary analgesic effect, a hypothesis that warrants a clinical trial on traumatized muscles.
authors.forename: Babak
authors.initials: B
authors.lastname: Shadgan
authors.affiliation: Centre of International Collaborations on Repair Discoveries, University of British Columbia, Vancouver, Canada.
authors.forename: Sports
authors.initials: S
authors.lastname: Med
authors.affiliation: Cambridge University Hospital, United Kingdom. Dr Reid is now at Department of Physical Therapy, University of Toronto, ON, Canada.
authors.forename: Amir H
authors.initials: AH
authors.lastname: Pakravan
authors.affiliation: Department of Physical Therapy, University of British Columbia, Vancouver, Canada.
authors.forename: Alison
authors.initials: A
authors.lastname: Hoens
authors.affiliation: Department of Physical Therapy, University of British Columbia, Vancouver, Canada.
authors.forename: W Darlene
authors.initials: WD
authors.lastname: Reid
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D017679:Cryotherapy; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption / Q000502:physiology; D010108:Oxyhemoglobins / Q000378:metabolism; D052097:Quadriceps Muscle / Q000098:blood supply* / Q000502:physiology; D012879:Skin Physiological Phenomena; D019265:Spectroscopy, Near-Infrared
chemical_list: D006454:Hemoglobins; D010108:Oxyhemoglobins; D010100:Oxygen
keywords: analgesics; blood flow; cryotherapy; muscle injury