Validity, Reliability, and Inertia of Four Different Temperature Capsule Systems.

PURPOSE: Telemetric temperature capsule systems are wireless, relatively non-invasive and easily applicable in field conditions, and have therefore great advantages for monitoring core body temperature. However, the accuracy and responsiveness of available capsule systems have not been compared previously. Therefore, the aim of this study was to examine the validity, reliability and inertia characteristics of four ingestible temperature capsule systems (i.e. CorTemp, e-Celsius, myTemp and VitalSense). METHODS: Ten temperature capsules were examined for each system in a temperature controlled water bath during three trials. The water bath temperature gradually increased from 33°C to 44°C during Trial 1 and 2 to assess the validity and reliability, and from 36°C to 42°C in Trial 3 to assess the inertia characteristics of the temperature capsules. RESULTS: A systematic difference between capsule and water bath temperature was found for CorTemp (0.077°C±0.040°C), e-Celsius (-0.081°C±0.055°C), myTemp (-0.003°C±0.006°C) and VitalSense (-0.017°C±0.023°C) (p0.05). Comparable inertia characteristics were found for CorTemp (25±4 sec), e-Celsius (21±13 sec) and myTemp (19±2 sec), while the VitalSense system responded more slowly (39±6 sec) to changes in water bath temperature (p<0.001). CONCLUSION: Although differences in temperature and inertia were observed between capsule systems, an excellent validity, test-retest reliability, and inertia was found for each system between 36°C and 44°C after removal of outliers

Trainability of cold induced vasodilatation in fingers and toes

Subjects that repeatedly have to expose the extremities to cold may benefit from a high peripheral temperature to maintain dexterity and tissue integrity. Therefore, we investigated if repeated immersions of a hand and a foot in cold water resulted in increased skin temperatures. Nine male and seven female subjects (mean 20.4; SD 2.2 years) immersed their right (trained) hand and foot simultaneously in 8°C water, 30 min daily for 15 days. During the pre and post-test (days 1 and 15, respectively) the left (untrained) hand and foot were immersed as well. Pain, tactile sensitivity and skin temperatures were measured every day. Mean (SD) toe temperature of the trained foot increased from 9.49°C (0.89) to 10.03°C (1.38) (p < 0.05). The trained hand, however, showed a drop in mean finger temperature from 9.28°C (0.54) to 8.91°C (0.44) (p < 0.001) and the number of cold induced vasodilation (CIVD) reactions decreased from 52% during the first test to 24% during the last test. No significant differences occurred in the untrained extremities. Pain diminished over time and tactile sensitivity decreased with skin temperature. The combination of less CIVD responses in the fingers after training, reduced finger skin temperatures in subjects that did show CIVD and the reduced pain and tactile sensitivity over time may lead to an increased risk for finger cold injuries. It is concluded that repeated cold exposure of the fingers does not lead to favorable adaptations, but may instead increase the injury risk

Cross Adaptation - Heat and Cold Adaptation to Improve Physiological and Cellular Responses to Hypoxia

To prepare for extremes of heat, cold or low partial pressures of O2, humans can undertake a period of acclimation or acclimatization to induce environment specific adaptations e.g. heat acclimation (HA), cold acclimation (CA), or altitude training. Whilst these strategies are effective, they are not always feasible, due to logistical impracticalities. Cross adaptation is a term used to describe the phenomenon whereby alternative environmental interventions e.g. HA, or CA, may be a beneficial alternative to altitude interventions, providing physiological stress and inducing adaptations observable at altitude. HA can attenuate physiological strain at rest and during moderate intensity exercise at altitude via adaptations allied to improved oxygen delivery to metabolically active tissue, likely following increases in plasma volume and reductions in body temperature. CA appears to improve physiological responses to altitude by attenuating the autonomic response to altitude. While no cross acclimation-derived exercise performance/capacity data have been measured following CA, post-HA improvements in performance underpinned by aerobic metabolism, and therefore dependent on oxygen delivery at altitude, are likely. At a cellular level, heat shock protein responses to altitude are attenuated by prior HA suggesting that an attenuation of the cellular stress response and therefore a reduced disruption to homeostasis at altitude has occurred. This process is known as cross tolerance. The effects of CA on markers of cross tolerance is an area requiring further investigation. Because much of the evidence relating to cross adaptation to altitude has examined the benefits at moderate to high altitudes, future research examining responses at lower altitudes should be conducted given that these environments are more frequently visited by athletes and workers. Mechanistic work to identify the specific physiological and cellular pathways responsible for cross adaptation between heat and altitude, and between cold and altitude, is warranted, as is exploration of benefits across different populations and physical activity profiles

Digital Rewarming Patterns After Median and Ulnar Nerve Injury

Purpose Posttraumatic cold intolerance (CI) is a frequent and important sequel after peripheral nerve injury. In this study, it is hypothesized that altered rewarming patterns after peripheral nerve injury are related to the degree of posttraumtic CL This hypothesis is tested by quantitatively comparing rewarming patterns of the digits in controls and in median or ulnar nerve injury patients and by investigating relationships between rewarming patterns, sensory recovery, and CI. Methods Twelve median or ulnar nerve injury patients with a follow-up of 4 to 76 months after nerve repair and 13 control subjects had isolated cold stress testing of the hands. Video thermography was used to analyze and compare rewarming patterns of the injured and uninjured digits after cold stress testin. Temperature curves were analyzed by calculating C the Q value as an indicator of heat transfer (temperature added during the first 10 minutes after start of active rewarming) and the maximum slope. Results Test-retest reliability was 0.64 and 0.79, respectively, for the Q value and maximum slope. High Q values and maximum slopes were interpreted as the presence of active rewarming. Patients with return of active rewarming had better sensory recovery and lower C, Blond McIndoe Cold Intolerance Severity Scale (CISS) scores. Better sensory recovery was correlated with lower CISS scores. Conclusions Test-retest reliability of cold stress testing was good, and we found a difference in rewarming patterns between nerve injury patients and controls. The presence of active rewarming in the nerve injury patients was related to sensory recovery and fewer complaints of posttraumatic CI. (J Hand Surg 2009;34A:54-64. Copyright (C) 2009 by the American Society for Surgery of the Hand. All rights reserved.

Cold-induced vasodilatation in cold-intolerant rats after nerve injury

Purpose: Cold-induced vasodilatation (CIVD) is a cyclic regulation of blood flow during prolonged cooling of protruding body parts. It is generally considered to be a protective mechanism against local cold injuries and cold intolerance after peripheral nerve injury. The aim of this study was to determine the role of the sympathetic system in initiating a CIVD response. Methods: Eight rats were operated according to the spared nerve injury (SNI) model, eight underwent a complete sciatic lesion (CSL) and six underwent a sham operation. Prior to operation, 3, 6 and 9 weeks postoperatively, both hind limbs were cooled and the skin temperature was recorded to evaluate the presence of CIVD reactions. Cold intolerance was determined using the cold plate test and mechanical hypersensitivity measured using the Von Frey test. Results: No significant difference in CIVD was found comparing the lateral operated hind limb for time (preoperatively and 3, 6 and 9 weeks postoperatively; p = 0.397) and for group (SNI, CSL and Sham; p = 0.695). SNI and CSL rats developed cold intolerance and mechanical hypersensitivity. Conclusion: Our data show that the underlying mechanisms that initiate a CIVD reaction are not affected by damage to a peripheral nerve that includes the sympathetic fibres. We conclude that the sympathetic system does not play a major role in the initiation of CIVD in the hind limb of a rat. Clinical relevance: No substantial changes in the CIVD reaction after peripheral nerve injury imply that the origin of cold intolerance after a traumatic nerve injury is initiated by local factors and has a more neurological cause. This is an important finding for future developing treatments for this common problem, as treatment focussing on vaso-regulation may not help diminish symptoms of cold-intolerant patients. (C) 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons