Purpose: The aim of the study was to assess thermal effects and cardiovascular autonomic control with application of a gaseous cryotherapy device to the hand.
Material and methods: Before, during and after cooling of the left hand, we continuously evaluated cutaneous temperature of the right and left hands, as well as heart rate (HR) and arterial blood pressure (BP) and their neurovegetatif control (HR and BP variability) in 8 healthy subjects. Comparison of cooling caused by projection of CO(2) microcrystals (2 min) under high pressure (75 bar) and low temperature (-78 degrees C) to that with application of a latex ice pack (15 min). Assessment of whether cooling triggered any changes in cardiovascular autonomic control, especially as compared with responses by the hand cold-pressure test (2 min).
Results: CO(2) projection in the left hand induced a steep decrease (-26 degrees C) in temperature followed by a rapid increase and a cutaneous vasoconstriction of the right hand, with significant increases in BP and cardiac parasympathetic activity. Cardiovascular responses were similar to those with application of the hand cold-pressure test. Application of an ice pack decreased cutaneous temperature to a lesser extent (-19 degrees C) and more slowly, without changing BP or indices of HR and BP variability.
Conclusion: CO(2) projection caused "thermal shock" and triggered a systemic cutaneous vasoconstriction response, with activation of indices of both ortho- and parasympathetic activity, as with the hand cold-pressure test. Vascular responses during ice pack cooling appeared solely localised to the cooled area, without any significant change in autonomic cardiovascular control.