Effects of Salted ice bags on surface and intramuscular cooling and rewarming rates

1. Effects of Salted ice bags on surface and intramuscular cooling and rewarming rates Presented by: Eric Hunter and Caitlyn Crowley

2. Literature review • Cryotherapy is used among healthcare providers to treat acute injuries by reducing pain and limiting the formation of swelling. 1,2 • Lowers the metabolic rate decreasing the amount of oxygen needed. • No optimal temperature has been set to effectively limit the negative effects of inflammation.3,4 • Colder the tissues the better….. No benefit found below 5°C. 4

3. Literature review • Ice bags have been shown to be the most effective at cooling tissue when compared to other packs (gel, chemical). 5,6, 7 • They cool intra-muscular temperature the fastest and get the coldest. • Skin/intramuscular tissue continue cooling longer after the modality has been removed • Skin/intramuscular tissuetake longer to re-warm to normal temperature • Wetted Ice bags are the most effective at decreasing skin and intramuscular temperature when compared with normal cubed or crushed ice bags. 3 • Continued research has looked at most effective ways to cool tissues. • No one has looked at adding salt to an ice bag

4. Theory • Using knowledge of basic science • Adding salt to H2O decreases freezing points • Pilot study has demonstrated ability to decrease water temperature by adding salt

5. Pilot data • Control Condition: 2000 mL wetted ice  0.5 C • Experimental Conditions: 2000 mL ice + uniodized salt

6. Why important to AT Field • Decreased tissue temperature • Decrease effects of secondary hypoxic injury • Potentially decreased treatment times • Faster numbing (less cold pain) • Better patient compliance if treatment doesn’t take as long? • Potentially longer re-warming time • Secondary hypoxic injury is reduced for a longer time • May result in less time loss from injury

7. Study design • Repeated-measures • Counterbalanced • ABC, ACB, BCA, BAC, CAB, CBA • Three treatment groups • Wetted cubed ice (A) • Current best practice • Salted cubed ice (B) • Salted crushed ice (C) • Independent variable • Time • Group • Dependent variable • Temperature • Skin • Intramuscular

8. Participants 24 subjects Exclusion Criteria 18-26 Healthy Male and Female No known vascular disease in lower leg No injury to lower leg in the last month or during the study No sensitivity to cold Not allergic to cold/ice No compromised circulation of the lower leg

9. recruitment • Fliers • Tear offs • QR Scan • Announcements in class

10. Measurement tools • Skinfold calipers • Skyndex, Cadwell, Justiss and Co, Inc., Fayetteville, AR • Surface thermocouple • SST-1, Physitemp Instruments, Inc, Clifton, NJ OR Omega thermocouples • 26-gauge hypodermic needle microprobe • Physitemp MT-26/4, Physitemp Instruments, Inc, Clifton, NJ • Microprocessor thermometer • Model HH23, Omega Engineering, Inc, Stamfort, CT)

11. conditions • Wetted ice bag • Cramer ice bag • 2000 mL cubed ice • 300 mL room temperature water • Salted crushed ice bag • Cramer ice bag • 1 TbspMorton Unionized Salt • 2000 mL crushed ice • Salted cubed ice bag • Cramer ice bag • 1 Tbs Morton Uniodized Salt • 2000 mL cubed ice

12. Anticipated Procedures • Training on insertion at BYU by Dr. David Draper & colleagues • Calf measurements taken to determine location of largest girth where microprobe will be inserted on the posterior lateral portion of the calf. • Skinfold measurements will be taken 3 times and then the average will be used • Divide mean measurement by 2 for amount of subcutaneous fat • For intramuscular depth measure a vertical distance of 2 cm plus the ½ mean skinfold • Mark the lateral aspect of the lateral head of the gastrocnemius using a fabricated template labeled to the nearest millimeter to ensure proper insertion point • Insertion of microprobe and placement of surface thermocouple on participants by the same two researchers

13. Anticipated Procedures • Insertion area will be shave and cleaned prior to insertion • Baseline period of 20 minutes for intramuscular temperatures to reach plateau (participants lying prone on table for entire process) • Ice condition applied • Treatment time of 20 minutes • Ice removed • Recovery time of 45 minutes • Surface thermocouple, treatment template and microprobe will be removed • Area will be cleaned and covered with a self-adhesive bandage ** Temperatures will recorded every 30 seconds throughout the study

14. Timeline • Spring semester 2013 • Training in microprobe insertion techniques • Secure funding • Subject recruitment period • Beginning September 2013 • Data collection period • September - November 2013 • Data analysis period • November 2013 • Prepared to defend/prepare manuscript for publication!! • Spring 2014

15. Statistical analysis • Repeated measure ANOVA • Skin temperature • Baseline, 30-second intervals for 20-minute treatment time, 30-second intervals for 45 minute rewarming period • Intramuscular temperature • Baseline, 30-second intervals for 20-minute treatment time, 30-second intervals for 45 minute rewarming period • Microprocessor thermometer will be video recorded to ensure accurate temperature capture at desired intervals

16. Null Hypotheses • There will be no difference in surface and intramuscular cooling and rewarming rates between the three treatment conditions.

17. Research Hypotheses • Both salted crushed/cubed will decrease skin temperature more than wetted ice • Both salted crushed/cubed will decrease intramuscular temperature more than wetted ice • Both salted crushed/cubed will have longer skin temperature rewarming times than wetted ice • Both salted crushed/cubed will have longer intramuscular temperature rewarming times than wetted ice • Salted cubed ice will decrease skin temperature more than salted crushed ice • Salted cubed ice will decrease intramuscular temperature more than salted crushed ice

18. Challenges/limitations • Ice bag falling off • Template on skin • Limited rewarming time • Initial/exploratory study

19. Funding • NATA grant • $1,000 • University grant • Moyes Academic Support & Technology Endowment Committee • Funds used for • Microprobes • Thermocouples • Ice bags • Salt • Sanitizing and sterilizing materials • Adhesive bandages • Subject incentive

20. References • 1. Dolan MG, Thornton RM, Fish DR, Mendel FC. Effects of Cold Water Immersion on Edema Formation After Blunt Injury to the Hind Limbs of Rats. J Athl Train. 1997;32(3):233–237. • 2. Meeusen R, Lievens P. The use of cryotherapy in sports injuries. Sports Med. 1986;3(6):398–414. • 3. Merrick MA, Jutte LS, Smith ME. Cold Modalities With Different Thermodynamic Properties Produce Different Surface and Intramuscular Temperatures. J Athl Train. 2003;38(1):28–33. • 4. Sapega AA, Heppenstall RB, Sokolow DP, et al. The bioenergetics of preservation of limbs before replantation. The rationale for intermediate hypothermia. J Bone Joint Surg Am. 1988;70(10):1500–1513. • 5. Dykstra JH, Hill HM, Miller MG, Cheatham CC, Michael TJ, Baker RJ. Comparisons of Cubed Ice, Crushed Ice, and Wetted Ice on Intramuscular and Surface Temperature Changes. J Athl Train. 2009;44(2):136–141. • 6. Kennet J, Hardaker N, Hobbs S, Selfe J. Cooling Efficiency of 4 Common Cryotherapeutic Agents. J Athl Train. 2007;42(3):343–348. • 7. Myrer JW, Draper DO, Durrant E. Contrast Therapy and Intramuscular Temperature in the Human Leg. J Athl Train. 1994;29(4):318–322.

21. Any questions?