Hyperbaric gaseous cryotherapy: effects on skin temperature and systemic vasoconstriction

Evaluation of thermal shock therapy for reducing pain during intense pulsed light therapy: An intrapatient randomized controlled study

BACKGROUND

Intense pulsed light (IPL) is used for the treatment and improvement of various skin issues. However, patients often experience local skin burning and pain after IPL treatment. Cooling and analgesic measures are indispensable.

AIMS

To investigate the clinical effect of thermal shock therapy on pain relief and reduction of adverse reactions during IPL therapy.

PATIENTS/METHODS

A total of 60 female patients with facial photoaging who received IPL therapy were enrolled in the study. As a comparative split-face study, one side of the face was randomly selected as the control side. The other side was given thermal shock therapy before and after the IPL treatment immediately as analgesic side. The visual analog scale (VAS) was used to evaluate the pain degree of the patients. The telephone follow-ups regarding the occurrence of adverse reactions were conducted respectively on the 2nd day, 7th day, and 1 month after treatment.

RESULTS

The VAS score and skin temperature of analgesia side was lower than that of control side at different stages of treatment. In terms of adverse reactions, the incidence of transient facial redness on the analgesic side was lower than that on the control side. Two patients showed slight secondary pigmentation on the control side, and the other patients showed no other adverse reactions on both sides.

CONCLUSIONS

Thermal shock therapy assisted IPL therapy can reduce skin temperature during treatment, effectively relieve patients' pain, reduce the occurrence of adverse reactions caused by heat injury, and improve patients' comfort level.

Is Whole-Body Cryostimulation an Effective Add-On Treatment in Individuals with Fibromyalgia and Obesity? A Randomized Controlled Clinical Trial

Pain severity, depression, and sleep disturbances are key targets for FM rehabilitation. Recent evidence suggests that whole-body cryostimulation (WBC) might be an effective add-on treatment in the management of FM. The purpose of this study was to evaluate the effects of an add-on WBC intervention to a multidisciplinary rehabilitation program on pain intensity, depressive symptoms, disease impact, sleep quality, and performance-based physical functioning in a sample of FM patients with obesity. We performed a randomized controlled trial with 43 patients with FM and obesity undergoing a multidisciplinary rehabilitation program with and without the addition of ten 2-min WBC sessions at −110 °C over two weeks. According to our results, the implementation of ten sessions of WBC over two weeks produced additional benefits. Indeed, both groups reported positive changes after the rehabilitation; however, the group that underwent WBC intervention had greater improvements in the severity of pain, depressive symptoms, disease impact, and quality of sleep. On the contrary, with respect to performance-based physical functioning, we found no significant between-group differences. Our findings suggest that WBC could be a promising add-on treatment to improve key aspects of FM, such as pain, depressive symptoms, disease impact and poor sleep quality.

Direct Effect of Local Cryotherapy on Muscle Stimulation, Pain and Strength in Male Office Workers with Lateral Epicondylitis, Non-Randomized Clinical Trial Study

Background: Local cryotherapy (LC) is one of the physiotherapeutic methods used in the conservative treatment of lateral epicondylitis (LE). The aim of the study was to verify the direct effect of a single LC procedure on the clinical symptoms of lateral epicondylitis enthesopathy (pain, pain free grip, PFG) and its effect on the bioelectrical properties of the wrist extensor muscles at rest, on maximal contraction and isometric contraction during fatigue. Methods: The study group was 28 men (35.4 ± 6.13 years) with confirmed unilateral epicondylitis. The performed procedures included the assessment of pain (visual analogue scale, VAS), PFG and ARMS (root-mean-square amplitude) and mean frequencies (MNF) of the sEMG signal before (T0) and after (T1) LC on the side with enthesopathy (ECRE) and without enthesopathy (ECRN/E). Results: There was an increase in the ARMS values of the signals recorded during rest and MVC from the ECR muscles both with and without enthesopathy (p = 0.0001, p = 0.006), an increased PFG after LC only on the side with LE (p < 0.0001) and decreased pain (p < 0.0001). During isometric fatigue contraction, a higher ARMS on both the ECRE side (p < 0.0001) and the ECRN/E side (p < 0.0001) was observed after LC treatment, and a lower MNF was observed on both the ECRN/E side (p < 0.0001) and the ECRE side (p < 0.0001) after LC. Conclusions: LC reduces the pain and increases PFG and muscle excitation expressed by ARMS and seems to delay muscle fatigue.

Whole-Body Cryostimulation: A Rehabilitation Booster in Post-COVID Patients? A Case Series

Given the severity and prevalence of post-COVID-19 symptoms in the general population, the identification of boosters for rehabilitation programs appears to be of paramount importance. The purpose of this case series is to provide some preliminary evidence about the role of whole-body cryostimulation (WBC) as an effective adjuvant for the recovery of patients with the post-COVID-19 condition (PCC). We recruited seven patients with previously confirmed SARS-CoV-2 infection and symptoms of PCC of different severities for a comprehensive rehabilitation program, including WBC. The main symptoms were dyspnea, chronic and muscular fatigue, chronic pain, and poor sleep quality. Moreover, some patients presented high levels of hematological markers of inflammation. Because we provided a range of interventions, including nutritional and psychological support along with physical exercise and physiotherapy, we could not determine to what extent WBC may per se have accounted for the clinical and functional improvements. However, for all reported cases, it was observed that the introduction of WBC sessions represented a turning point in the patient’s subjective and objective improvements related to health and functioning.

Hyperbaric gaseous cryotherapy for postoperative rehabilitation enhances functional recovery of canine stifle joint: a report on a short-term study

Background

Hyperbaric gaseous cryotherapy (HGC) is a type of cryotherapy used in human medicine for rehabilitation after orthopedic surgeries. Because HGC is known to reduce acute or chronic pain, research is needed to prove its effectiveness in veterinary medicine.

Objectives

To compare the effects of HGC between the HGC treatment group and the nontreatment (NT) group on postoperative swelling, range of motion, lameness score, postoperative pain, and kinetic measurements after stifle joint surgery in dogs.

Methods

Dogs were randomized in an HGC group or NT groups. In the HGC group, HGC was applied once a day for a total of 2 days after surgery. All parameters were measured postoperatively and at 1, 2, 10, and 28 days after surgery.

Results

Twenty dogs were enrolled: 10 in the HGC group and 10 in the NT group. Soft tissue swelling was not significantly different between groups at any time point. In the HGC group, pain scores decreased significantly 24 h after surgery and 48 h after surgery. Dogs in the HGC group showed a significantly decreased lameness and improvement for all kinetic measurements beginning 48 h after surgery. In addition, the HGC group indicated a significant increase in range of motion as compared with the NT group at 28 days after surgery.

Conclusions

HGC plays a powerful role in decreasing initial postoperative pain. Furthermore, the improvement in pain affects the use of the operated limb, and the continued use of the limb eventually assists in the quick recovery of normal function.

Is it time to put traditional cold therapy in rehabilitation of soft-tissue injuries out to pasture?

Cold therapy has been used regularly as an immediate treatment to induce analgesia following acute soft-tissue injuries, however, a prolonged ice application has proved to delay the start of the healing and lengthen the recovery process. Hyperbaric gaseous cryotherapy, also known as neurocryostimulation, has shown the ability to overcome most of the limitations of traditional cold therapy, and meanwhile promotes the analgesic and anti-inflammatory effects well, but the current existing studies have shown conflicting results on its effects. Traditional cold therapy still has beneficial effect especially when injuries are severe and swelling is the limiting factor for recovery after soft-tissue injuries, and therefore no need to be entirely put out to pasture in the rehabilitation practice. Strong randomized controlled trials with good methodological quality are still needed in the future to evaluate the effects of different cryotherapy modalities.

Assessment of the Dynamics of Temperature Changes in the Knee Joint Area in Response to Selected Cooling Agents in Thermographic Tests

Although local cryotherapy (LC) is performed with various cooling agents (C_Ag) such as ice, water, and gasses, in clinical practice, it is mostly performed with cooling gasses. Presently, LC with cooling gasses is very popular but the inference about the thermal (stimulus) effect on the tissues is mainly based on research carried out using ice packs. The proposed objective of the study was to evaluate the dynamics of temperature changes in the knee joint area in response to a 3-min exposure to liquid nitrogen vapors (LNVs), cold air (CA) and ice bag (IB). The study group included 23 healthy volunteers with an average age of 26.67 ± 4.56. The exposed (ROI_E) and contralateral (ROI_NE) areas of the knee joint after exposure to C_Ag were observed. Immediately after 3 min of LC, the ROI_E temperature dropped by 10.11 ± 0.91 °C after LNV, 7.59 ± 0.14 °C after IB and 6.76 ± 1.3 °C after CA. Significant tissue cooling was maintained up to 15 min after LNV (p < 0.01), 10 min after IB (p < 0.05) and 5 min after CA (p < 0.05). LC causes significant temperature changes both in ROI_E and ROI_NE. The greatest cooling potential was demonstrated for LNV and the lowest for CA.

Serial whole-body cryotherapy in fibromyalgia is effective and alters cytokine profiles

Introduction

Whole-body cryotherapy (WBC) has shown to be beneficial in the treatment of fibromyalgia (FM). There is cumulative evidence that cytokines play a crucial role in FM. It’s unknown whether clinical effects of WBC can be demonstrated at the molecular level and how long the effects last.

Methods

We compared effects of serial WBC (6 sessions (− 130 °C in 6 weeks) in FM patients and healthy controls (HC). Primary outcome was the change in pain level (visual analogue scale 0–100 mm) after 6 sessions. Secondary outcomes were a change in disease activity (revised Fibromyalgia Impact Questionnaire) and pain after 3 sessions and 3 months after discontinued therapy and in cytokine levels (interleukin (IL-)1, IL-6, tumor necrosis factor α (TNF-α) and IL-10). The patients’ opinions on the satisfaction, effectiveness and significance of WBC were evaluated.

Results

Twenty-three FM patients and 30 HC were enrolled. WBC resulted in a significant reduction in pain and disease activity after 3 and 6 sessions. No clinical benefit could be measured 3 months after discontinued treatment. Overall, probands were satisfied with WBC and considered WBC to be important and effective. FM patients had significantly different levels of IL-1, IL-6, TNF-α and IL-10 at each reading point compared to HC. Levels of IL-1, IL-6 and IL-10 were significantly altered over time in FM patients. Compared to HC FM patients showed a significantly different response of IL1, − 6 and − 10 to WBC.

Conclusion

Serial WBC is a fast acting and effective treatment for FM. Proven effects of WBC may be explained by changes in cytokines.

Should ice application be replaced with neurocryostimulation for the treatment of acute lateral ankle sprains? A randomized clinical trial

Study design

Single-blind parallel group randomized clinical trial.

Objectives

To compare the effects of neurocryostimulation (NCS) with those of traditional ice application on functional recovery, pain, edema and ankle dorsiflexion range of motion (ROM) in individuals receiving physiotherapy treatments for acute lateral ankle sprains (LAS).

Background

Ankle sprain is a very common injury and its management is often costly, with important short- and long-term impacts on individuals and society. As new methods of therapy using cold (cryotherapy) are emerging for the treatment of musculoskeletal conditions, little evidence exists to support their use. NCS, which provokes a rapid cooling of the skin with the liberation of pressured CO², is a method believed to accelerate the resorption of edema and recovery in the case of traumatic injuries.

Methods

Forty-one participants with acute LAS were randomly assigned either to a group that received in-clinic physiotherapy treatments and NCS (experimental NCS group, n = 20), or to a group that received the same in-clinic physiotherapy treatments and traditional ice application (comparison ice group, n = 21). Primary (Lower Extremity Functional Scale - LEFS) and secondary (visual analog scale for pain intensity at rest and during usual activities in the last 48 h, Figure of Eight measurement of edema, and weight bearing lunge for ankle dorsiflexion range of motion) outcomes were evaluated at baseline (T0), after one week (T1), two weeks (T2), four weeks (T4) and finally, after six weeks (T6). The effects of interventions were assessed using two-way ANOVA-type Nonparametric Analysis for Longitudinal Data (nparLD).

Results

No significant group-time interaction or group effect was observed for all outcomes (0.995 ≥ p ≥ 0.057) following the intervention. Large time effects were however observed for all outcomes (p <  0.0001).

Conclusion

Results suggest that neurocryostimulation is no more effective than traditional ice application in improving functional recovery, pain, edema, and ankle dorsiflexion ROM during the first six weeks of physiotherapy treatments in individuals with acute LAS.

Level of evidence

Therapy, level 1b.

Trial registration

ClinicalTrials.gov, NCT02945618. Registered 23 October 2016 - Retrospectively registered (25 participants recruited prior to registration, 17 participants after).

Preliminary study on the effect of sex on skin cooling response during whole body cryostimulation (-110 °C): Modeling and prediction of exposure durations

In order to determine the required duration of whole-body exposure to extreme cold (-110 °C) in males and females for achieving the same cold-induced response, a mathematical model of skin cooling kinetics was developed. This modeling is derived from the implementation of a new experimental cryotherapy protocol to obtain continuous skin temperature maps over time. Each 3-min whole-body cryostimulation session was divided into six incremental sessions of 30 s carried out over six consecutive days. Seventeen young, healthy subjects (8 males aged 22.6 ±3.0 years and 9 females aged 23.7 ±4.7 years) agreed to participate in this study. The smallest sex-related difference in temperature was found in the trunk area (2.93 °C after 3 min) while the greatest temperature drop was found in the lower limbs (5.92 °C after 3 min). The largest temperature variation was observed between the trunk and the lower limbs, and peaked at 2.67 °C in males and 6.99 °C in females. For both sexes, skin cooling kinetics showed a strong transient exponential type decrease followed by linear regression behavior. It appeared that for achieving the same cold-induced response, the required duration of cryostimulation is longer for males. For example, a trunk skin cooling of -12 °C could be achieved in 125s for females vs 170s for males (+36% longer); for the lower limbs, the same skin cooling magnitude could be reached after 87s for females vs 140s for males (+62% longer).

Affective response to whole-body cryotherapy: Influence of sex, body mass index, age, time of day, and past experience

OBJECTIVE

Whole-Body Cryotherapy (WBC) has seen a recent surge in popularity with patients with inflammatory conditions, athletes, and even people seeking to improve general health and quality of life. WBC treatment usually requires participation in a dozen of 3-min long sessions. But compliance is considered difficult due to possible cold-induced unpleasant sensations. Based on hedonic psychology assumptions, ratings of pleasure-displeasure experienced during a taks or activity may be important to understand individual differences in attendance.

METHODS

Two hundred fifty nine customers from two French cryocenters took the Feeling Scale immediately after their first WBC session.

RESULTS

End affect appeared to be negatively valenced (M = -1.85, SD = 1.38, 95 % confidence interval: -2.02 to -1.68). Additional statistical analyses revealed a moderating influence of past experience, in women only. Similarly, BMI was found to be negatively associated with displeasure in women, but not in men.

CONCLUSION

These findings are discussed and further research directions are suggested.

Local ice cryotherapy decreases synovial interleukin 6, interleukin 1β, vascular endothelial growth factor, prostaglandin-E2, and nuclear factor kappa B p65 in human knee arthritis: a controlled study

Background

The aim of this study was to assess the anti-inflammatory effects of local cryotherapy in human non-septic knee arthritis.

Methods

In the phase I of the study, patients were randomized to receive either ice (30 min; N = 16) or cold CO₂ (2 min; N = 16) applied twice during 1 day at an 8-h interval on the arthritic knee. In phase II, 16 other ice-treated arthritic knees according to the same protocol were compared to the contralateral non-treated arthritic knees (N = 16). The synovial fluid was analyzed just before the first cold application, then 24 h later. IL-6, IL-1β, TNF-α, IL-17A, VEGF, NF-kB-p65 protein, and PG-E2 levels were measured in the synovial fluid and compared before/after the two cold applications.

Results

Forty-seven patients were included (17 gouts, 11 calcium pyrophosphate deposition diseases, 13 rheumatoid arthritides, 6 spondyloarthritides). Local ice cryotherapy significantly reduced the IL-6, IL-1β, VEGF, NF-kB-p65, and PG-E2 synovial levels, especially in the microcrystal-induced arthritis subgroup, while only phosphorylated NF-kB-p65 significantly decreased in rheumatoid arthritis and spondyloarthritis patients. Cold CO₂ only reduced the synovial VEGF levels. In the phase II of the study, the synovial PG-E2 was significantly reduced in ice-treated knees, while it significantly increased in the corresponding contralateral non-treated arthritic knees, with a significant inter-class effect size (mean difference − 1329 [− 2232; − 426] pg/mL; N = 12).

Conclusions

These results suggest that local ice cryotherapy reduces IL-6, IL-1β, and VEGF synovial protein levels, mainly in microcrystal-induced arthritis, and potentially through NF-kB and PG-E2-dependent mechanisms.

Trial registration

Clinicaltrials.gov, NCT03850392—registered February 20, 2019—retrospectively registered

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1965-0) contains supplementary material, which is available to authorized users.

Effects of microcurrent and cryotherapy on C-reactive protein levels and muscle tone of patients with rotator cuff reconstruction

[Purpose] The purpose of the present study was to apply early intervention via microcurrent and cryotherapy in patients who underwent rotator cuff reconstruction surgery, and to investigate the effects of such interventions on pain and inflammation levels based on the analysis of C-reactive protein (CRP) levels, and on changes in muscle tone. [Subjects and Methods] The study population consisted of 30 patients who had undergone rotator cuff reconstruction surgery, with 10 patients each assigned to the control, experimental I (E-1), and experimental II (E-II) groups. On the day after surgery, muscle tone, blood CRP level, and pain were measured. For the following two weeks, continues passive motion (CPM), icing, cryotherapy, and microcurrent were applied to the each group. After the respective interventions, CRP levels, pain, and muscle tone near the shoulder area were measured again. [Results] In the post-hoc test of between-group comparison, a statistically significant difference in CRP level was found in the cryotherapy group. A difference in shoulder muscle tone appeared only in the supraspinatus muscle, with post-hoc test results showing that the biggest change occurred in the cryotherapy group. [Conclusion] Cryotherapy may be able to help stabilize inflammation as well as reduce pain and muscle tension when applied in patients following rotator cuff reconstruction.

Theoretical modeling of time-dependent skin temperature and heat losses during whole-body cryotherapy: A pilot study

This article establishes the basics of a theoretical model for the constitutive law that describes the skin temperature and thermolysis heat losses undergone by a subject during a session of whole-body cryotherapy (WBC). This study focuses on the few minutes during which the human body is subjected to a thermal shock. The relationship between skin temperature and thermolysis heat losses during this period is still unknown and have not yet been studied in the context of the whole human body. The analytical approach here is based on the hypothesis that the skin thermal shock during a WBC session can be thermally modelled by the sum of both radiative and free convective heat transfer functions. The validation of this scientific approach and the derivation of temporal evolution thermal laws, both on skin temperature and dissipated thermal power during the thermal shock open many avenues of large scale studies with the aim of proposing individualized cryotherapy protocols as well as protocols intended for target populations. Furthermore, this study shows quantitatively the substantial imbalance between human metabolism and thermolysis during WBC, the explanation of which remains an open question.

Cryotherapy on postoperative rehabilitation of joint arthroplasty

PURPOSE

The effectiveness of cryotherapy on joint arthroplasty recovery remains controversial. This systematic review was conducted to assess the effectiveness of cryotherapy in patients after joint arthroplasty.

METHODS

Comprehensive literature searches of several databases including Cochrane Library (2013), MEDLINE (1950-2013), and Embase (1980-2013) were performed. We sought randomised controlled trials that compared the experimental group received any form of cryotherapy with any control group after joint arthroplasty. The main outcomes were postoperative blood loss, adverse events, and pain. Analyses were performed with Revman 5.0. Results were shown as mean differences (MD) and standard deviations or as risk difference and 95 % confidence intervals (CIs).

RESULTS

Ten trials comprised 660 total knee arthroplastys and three trials comprised 122 total hip arthroplastys (THAs) met the inclusion criteria. Blood loss was significantly decreased by cryotherapy (MD = -109.68; 95 % CI -210.92 to -8.44; P = 0.03). Cryotherapy did not increase the risk of adverse effect (n.s.). Cryotherapy decreased pain at the second day of postoperative (MD = -1.32; 95 % CI -2.37 to -0.27; P = 0.0003), but did not decreased pain at the first and third day of postoperative (n.s.).

CONCLUSIONS

Cryotherapy appears effective in these selected patients after joint arthroplasty. The benefits of cryotherapy on blood loss after joint arthroplasty were obvious. However, the subgroup analysis indicated that cryotherapy did not decreased blood loss after THA. Cryotherapy did not increase the risk of adverse effect. Cryotherapy decreased pain at the second day of postoperative, but did not decreased pain at the first and third day of postoperative.

LEVEL OF EVIDENCE

II.

Effects of crushed ice and wetted ice on hamstring flexibility

Flexibility, which is the ability to move freely through a full range of motion (ROM), is desired to enhance the performance and decrease the likelihood of muscle injury. There are different techniques used to increase ROM and cryotherapy techniques to facilitation flexibility gains. However, the combination of stretching and type of cryotherapy agents are still confounding. The purpose was to determine which type of cryotherapy, crushed or wetted ice, would produce the greatest gains in hamstring ROM when followed by proprioceptive neuromuscular facilitation (PNF) stretching. Fifteen healthy subjects underwent 3 treatment conditions: crushed ice bag (crushed ice), wetted ice bag (wetted ice), and no ice bag (no ice). Subject's hamstring ROM was measured at baseline, then again after a 20-minute cryotherapy treatment session. Subjects were then stretched using a slow-reversal-hold-relax PNF technique followed by a final ROM measurement. A repeated measures analysis of variance showed significant differences between cryotherapy and measurement conditions. Post hoc testing indicated that no ice (75.49 ± 12.19° C) was significantly different from wetted ice (81.73 ± 10.34° C) and crushed ice (81.62 ± 13.19° C) at the end of the treatment session, and that no ice (85.27 ± 13.83° C) was significantly different than wetted ice (89.44 ± 11.31° C) and crushed ice (89.16 ± 13.78° C) after the stretching session. However, there were no differences between wetted ice and crushed ice. Results indicate that strength and conditioning specialists can increase ROM with both forms of ice in combination with PNF stretching more so than when using no ice at all.

Cryotherapy in inflammatory rheumatic diseases: a systematic review

The aim of this article was to review current evidence about cryotherapy in inflammatory rheumatic diseases (therapeutic and biological effects). For therapeutic effects, we performed a systematic review (PubMed, EMBASE, Cochrane Library, LILACS databases, unpublished data) and selected studies including non-operated and non-infected arthritic patients treated with local cryotherapy or whole-body cryotherapy. By pooling 6 studies including 257 rheumatoid arthritis (RA) patients, we showed a significant decrease in pain visual analogic scale (mm) and 28-joint disease activity score after chronic cryotherapy in RA patients. For molecular pathways, local cryotherapy induces an intrajoint temperature decrease, which might downregulate several mediators involved in joint inflammation and destruction (cytokines, cartilage-degrading enzymes, proangiogenic factors), but studies in RA are rare. Cryotherapy should be included in RA therapeutic strategies as an adjunct therapy, with potential corticosteroid and nonsteroidal anti-inflammatory drug dose-sparing effects. However, techniques and protocols should be more precisely defined in randomized controlled trials with stronger methodology.

Comparison of gaseous cryotherapy with more traditional forms of cryotherapy following total knee arthroplasty

OBJECTIVE

The aim of this study was to assess the efficacy of gaseous cryotherapy following total knee arthroplasty (TKA) and to compare it to routinely used strategies for applying cold therapy.

PATIENTS AND METHODS

Sixty-six patients undergoing primary unilateral TKA were randomized into three groups and received "gaseous cryotherapy (GC)", "cold pack" and "cryocuff" applications, respectively throughout the hospital stay. Primary outcomes (knee pain intensity, mobility and girth measurements) were recorded on preoperative day 1 as well as on postoperative day (POD) 7. Cutaneous temperature of the knee sides were also measured on POD7 just before and immediately after cold application.

RESULTS

Although skin temperature dropped to 14°C following GC versus 22 to 24°C for the other two applications (P<0,05), the three groups did not differ at POD7 regarding the three primary outcomes. No adverse effects were observed with any of the ways of application.

CONCLUSIONS

Gaseous cryotherapy was not more beneficial than routinely used strategies for applying cold therapy. Further studies with larger sample size and with a more frequent and closer gaseous cryotherapy applications are needed to confirm our results.

Temperature changes in rheumatoid hand treated with nitrogen vapors and cold air

The aim of the study was the thermovisual comparison of mean temperature of hand surface changes after local cryotherapy with vapors of nitrogen (−160°C) and cold air (−30°C). Forty-seven patients with rheumatoid arthritis (39 women and 8 men; average age 56.2 ± 10.5 years) were included in the study. They had the application of topic cryotherapy using nitrogen vapors or cold air on one hand. Main outcome measure was surface temperature of dorsal sides of the cooled and contralateral hands. Thermal images of both hands were taken before and up to 3 h after the treatment. One minute after application, nitrogen vapors induced decrease in surface skin temperature of the cooled hand from 28.9 ± 1.8°C to 17.9 ± 2.2°C, P < 0.05, whereas cold air from 29.4 ± 2.4°C to 23.1 ± 2.2°C, P < 0.05. However, significantly lower temperature was obtained with vapors of nitrogen (P < 0.05). Just after the treatment, a rapid rewarming occurred and hands reached baseline temperature in 15 min in both applications and they did not differ till the end of the procedure. Both nitrogen vapors and cold air induce similar temperature changes in hands with the exclusion of temperature obtained 1 min after the treatment. Changes in non-cooled hands indicate contralateral reaction.

The effect of quantity of ice and size of contact area on ice pack/skin interface temperature

OBJECTIVE

To determine the effect of quantity of ice and contact area on ice pack/skin interface temperature during a 20-minute cooling period.

DESIGN

Repeated measures.

SETTING

Laboratory setting in an educational institution.

PARTICIPANTS

Twenty healthy males aged between 18 and 22 years.

INTERVENTIONS

An ice pack was applied to the right thigh with compression using an elastic bandage. The effects of three packs measuring 18 cm x 23 cm containing 0.3, 0.6 and 0.8 kg of ice, and one pack measuring 20 cm x 25 m containing 0.6 kg of ice were compared.

MAIN OUTCOME MEASURE

The reduction in temperature at the ice pack/skin interface during 20-minute ice applications was monitored at 1-minute intervals.

RESULTS

The application of 0.8-kg and 0.6-kg ice packs led to a significantly greater decrease in the interface temperature compared with the 0.3-kg ice pack [0.8 kg vs. 0.3 kg: -2.35 degrees C, 95% confidence interval (CI) of the difference -3.36 to -1.34 degrees C; 0.6 kg vs. 0.3 kg: -2.95 degrees C, 95% CI -4.07 to -1.83 degrees C]. No significant difference in temperature was found between the 0.6-kg and 0.8-kg ice packs (0.8 kg vs. 0.6 kg: 0.6 degrees C, 95% CI -0.12 to 1.32 degrees C, P>0.05). The size of the contact area did not alter the degree of cooling significantly (difference between smaller and larger pack: 0.05 degrees C, 95% CI -0.93 to 1.03 degrees C, P>0.05). The lowest temperature during ice application was reached after 8-9 minutes of cooling.

CONCLUSION

Application of an ice pack containing at least 0.6 kg of ice leads to a greater magnitude of cooling compared with application of a 0.3-kg ice pack, regardless of the size of the contact area. Thus, clinicians should consider using ice packs weighing at least 0.6 kg for cold treatment.