2Heat is commonly classified into 3 major categories Chemical action associated with cell metabolismElectrical or magnetic currents as those found in diathermy devicesMechanical action as found with ultrasoundThe application of heat modalities is known as thermotherapy, and methods of heating are classified as being superficial or deep.
3Superficial heating agents must be capable of increasing skin temp within a range of 104-113°F. The transfer of heat to underlying tissues occurs via conduction, but superficial heating agents are limited to a depth of less than 2cm.The use of heat is indicated in the subacute and chronic inflammatory stages of injury.
4Because the effects of heat application are essentially opposite to those of cold, its use in the treatment of acute injuries should be avoided.Applying heat to an active inflammatory cycle will ↑ the rate of cell metabolism and accelerate the amount of hypoxic injury
6Local effects of heat application Vasodilation↑rate of cell metabolism↑ capillary permeablilty↑delivery of leukocytesEdema formationRemoval of metabolic waste↑ elasticity of ligaments, capsules, and muscleAnalgesia and sedation of nerves↑nerve conduction↓muscle tone↓ muscle spasmPerspiration
7Some systemic effects of Heat exposure* ↑ body temp↑ pulse rate↑ respiratory rate↓ blood pressure
8General Indications/Contraindications Subacute or chronic inflammatory conditionsReduction of subacute or chronic painSubacute or chronic muscle spasm↓ ROMHematoma resolutionReduction of Joint contracturesContraindicationsAcute injuriesImpaired circulationPoor thermal regulationAnesthetic areasNeoplasmsAbnormal tissue, such as a tumor, that grows at the expense of healthy tissues
9Effects on the injury response Despite heat and cold produce many of the same outcomes, decreased pain, for example, the timing of when to begin using heat modalities is much more criticalIf heat is applied too soon in the injury response cycle, the ↑cell metabolism causes an increase in the number of cells injured or destroyed because of hypoxia.↑ the inflammatory rate may possibly extend the acute and subacute stages
10Cellular responseFor each ↑ of 18°F in skin temp, the cells metabolic rate ↑ by a factor of 2-3.As the cell’s metabolic rate ↑, so does its demand for oxygen and nutrients.As with living organisms that consume energy, the amount of waste excreted from the cell ↑ as its activity ↑Also, ↑ metabolic rate ↑ tissue temp.
11Blood and fluid Dynamics Response of the body to heat is dilating local blood vesselsThe amount of dilation being greater in superficial vessels than in the deeper vessels↑ capillary flow results in an ↑ supply of oxygen, nutrients, and antibodies to the effected area
12The amount of edema is ↑, but the capability of removing it is greater ↑ capillary pressure forces edema and harmful metabolites from the injured area↑ permeability aids in the re-absorption of edema and the dissolution of hematomas.These wastes can drain into the venous or lymphatic systemsIf venous and lymphatic return is not encouraged, further edema occurs.
13Effects on inflammation Local application of heat accelerates inflammationSoft tissue repair is facilitated through an accelerated metabolic rate and ↑ blood supplyBlood flow must be ↑ to encourage the removal of cellular debris and to ↑ delivery of the nutrients necessary for the healing of tissues
14↑ oxygen stimulates the breakdown and removal of tissue debris and inflammatory metabolites Nutrients are delivered to the area to fuel the cells, and there is also an ↑ in the delivery of leukocytes, encouraging phagocytosis.
15Muscle Spasm and Tissue Elasticity ↑ temperature reduces the primary and secondary muscle spindles’ sensitivity to stretch↓ the amount of muscle spasm presentIncreasing blood flow and reducing local muscle metabolites further alleviate spasmMost muscular tissues are not directly heated by superficial heating agents
16ROM is subsequently improved by ↑ the extensibility of collagen and the viscosity and plastic deformation of tissuesThis effect alone is not sufficient to ↓ contractures or ↑ the elasticity of healthy tissuesNeither anterior laxity of the knee nor hamstring flexibility has been shown to be affected by heat modalities aloneTension, in the form of gentle stretching, is necessary to elongate muscle and capsular tissues while the tissues are still within the therapeutic range
17Pain ControlMechanical deformation and/or chemical irritation of nerve endings stimulate pain transmissionIn acute injuries, the primary cause of pain is the mechanical damage done to the tissue in the area.In the subacute and chronic stage of injury, ischemia and irritation cause chemical pain from certain chemical mediatorsMechanical pain is caused by increased swelling and the tension placed on the nerves by muscle spasm
18Mechanical pain is decreased by reducing the pressure on the nerves , thus lessening the pain-spasm-pain cycle.By encouraging venous and lymphatic return through the use of elevation and muscle contraction, the swelling is removed, decreasing interstitial pressureAn increase in temperature leads to a state of analgesia and sedation in the injured area by acting of free nerve endings.Nerve fiber are stimulated, blocking the transmission of pain with a conterirritant effect.This effect appears to last only as long as the stimulus of heat is applied
19Dissipation of heatWhen therapeutic heat is applied to the body, there is a rapid rise in skin temperatureThis rise occurs because energy is being absorbed faster than the cool blood delivered to the area can remove it.After approximately minutes of exposure, the temperature gradient begins to even out.At that point, the body is able to counteract the energy being applied by supplying an adequate amount of blood to cool the area
20At this time, the patient may claim that the modality has cooled down when, in fact, its intensity is unchanged.When a maximal vasodilation has occurred and the intensity of the treatment stays constant (or increases), the vessels begin to constrict.The phenomenon, known as rebound vasoconstriction, will occur approx 20 min into the treatment.This is the body’s attempt to save underlying tissues by sacrificing the superficial layer.If the intensity of the tx is too great or if the duration is to long, burns will resultMottling of the skin is a warning sign that tissue temp are rising to a dangerously high level.In this case, ghost white areas and beet-red splotches mark the patients skinWhen this occurs, the tx should be discontinued immediately
21Heat vs Cold How do you know when to use heat and when to use cold?? There are no clear cut answers to this question.Many articles have given definitive time frames, such as:Use cold for the first 24 hrsAnd use heat for the next 48 hrsUnfortunately, statements like these are incorrect and unjustified.
22One of this first statements made in this class was that the body heals an injury at its own rate. Not only does this rate vary from person to person but also it may vary from injury to injury in the same personThe patients physical and psychological state, as well as the type and amount of tissue damaged, factor into the time frame for required for healing.
23The decision-making process is similar to the steps involved when a pipe ruptures in the basement of a houseBefore bailing out the water and cleaning up the mess, you have to stop the leak.Likewise, before encouraging as increase in the rate of cell metabolism in an injured area, the active process of inflammation must be calmed down first.
24Remember cold is indicated under 3 conditions In the acute stages of the inflammation reactionBefore ROM exercisesAfter physical activityHeat application is indicated under 5 conditionsTo control inflammation reaction in its subacute or chronic stagesTo encourage tissue healingTo reduce edema and ecchymosisTo improve ROM before physical activity or rehabilitationTo promote drainage from an infected site
25Deciding whether to use heat or cold Does the body area feel warm to the touch?Is the injured area still sensitive to light or moderate touch?Does the amount of swelling continue to increase over time?Does swelling increase during activity?Does pain limit the joint’s ROM?Would you consider the acute inflammation process to still be active?Does the patient continue to display improvement with the use of cold modalities?If the answers to these questions are “No” heat can safely be used. As the number of “yes” answers increases, so does the indication for use of cold
26Paraffin BathA paraffin bath contains a mixture of was and mineral oil in the ratio of 7 parts wax to 1 part oilMelted paraffin is kept at a constant temperature of °FTemps for tx given to the lower extremity are decreased ( °F) because circulation is less efficientBecause of its low specific heat paraffin can provide approx 6 times the amount of heat as water
27Paraffin is a superficial heating agent used for delivering heat to small, irregular shaped areas FingersWristHandFootAlthough its use in sports medicine is limited, it is an effective method for delivering heat, and this form of application of paraffin is beneficial in chronic conditions in which ROM is not an essential part of the tx protocolArthritisChronic inflammatory conditions
28Effects on the IRCIn addition to the standard effects of heat, paraffin increases perspiration in the treated area which soften and moisturizes the skin
29Setup and ApplicationSeveral methods of application, each with its own advantages and disadvantagesParaffin can act as an insulator is allowed to dry on the skinWith this in mind, the amount of heat delivered can be adjusted by increasing or decreasing the wax layers
30Prep for treatmentTo avoid contamination of the mixture, the body part to be treated should be thoroughly cleaned and dried before treatment.Immersion bathThoroughly clean skinThe patient begins by dipping the body part into the paraffin and removing it. Allow this coat to dryDip the extremity into the wax 6-12 times to develop the amount of insulation necessary. Allow wax to dry between dips
31Instruct the patient to avoid touching the sides and bottom of the heating unit because burns may resultInstruct the patient who is receiving an immersion not to move the joints that are in the liquid. The cracking of the wax will allow fresh paraffin to touch the skin, increasing the risk of burnsAfter the treatment, scrape off the hardened paraffin and return it to the unit for reheating, or discard it
32Pack (glove) MethodThe glove method is the safest but least effective way for delivering heat to the body with paraffin waxThis method is recommended for those patients who are in the subacute stages of healing or have a vascular or nerve condition that would predispose them to burningThe body part may also be elevated during this form of paraffin application
33Thoroughly clean the body part Begin treatment by immersing the extremity in the wax so that it becomes completely covered. Remove the body part and allow wax to dryContinue dipping for 7-12 times allowing wax to dry between dipsAfter the final dip, cover the extremity with a plastic bag, aluminum foil, or wax paper. Then wrap and secure a terry cloth towel around the areaIf indicated, the body part may be elevated.Following the treatment, remove the towel and the inner layering. Scrape off the hardened paraffin and return it to the bath for reheating, or discard it
34Duration of treatmentParaffin treatments are given for minutes and may be repeated several times daily
35PrecautionsThe sensation of the paraffin is misleading as to the actual temp of the treatment. The temp of the paraffin is sufficient to cause burns, but its specific heat and thermal capacity requires a longer period of time to transfer the energyAvoid using paraffin with athletes who are required to catch or throw a ball or workers who are required to maintain a good grip after the treatment.
36Indications/contraindications Subacute or chronic inflammatory conditionsSkin infectionsPeripheral nerve injuries before electrical stimulationAnother modality should be considered if the patient lacks temp perceptionContraindicationsAcute conditionsPeripheral vascular diseaseAreas with sensory loss or scaringsunburns
38Infrared LampProvide radiant energy for superficial heating of the skinThey are considered radiant modalities because no medium is required to transmit energy2 typesNear infrared (luminous)Far infrared (nonluminous)Treatment energy is produced by passing an electrical current through a carbon or tungsten filament
39Luminous generators produce some degree of visible light The intensity of the treatment is controlled by adjusting the current flow through the filament or by changing the distance between the lamp and the tissuesLuminous generators produce some degree of visible lightWhich places them on the “near” end of the infrared spectrumBecause visible light is present, some of the treatment energy is reflected by the surface of the skinNonluminous generators do not produce visible lightPlacing them on the “far” end of the infrared spectrum
40Nonluminous infrared radiation is less penetrating than luminous It has effects at 2mm and at 5-10mm beneath the surface of the skinBecause nonluminous infrared is less penetrating, the skin being treated will feel warmer than with luminousNot commonly used in a clinical setting, because of the wide range of heating modalities availableHowever, it was once thought to assist in the healing of open wounds, such as turf burnsbut it actually deters the healing process because it dehydrates the tissues
41Effect on the IRC Heats the skin almost exclusively Deeper tissues are heated by conduction to depths up to 1 cm.Primary physiological effects occur almost entirely in the superficial skinHyperemia occurs as a result of increased capillary flow and increased capillary pressure
42Setup and application Warm up the lamp if necessary To prevent the concentration of heat, clean the area of any sweat, dirt, or oils, and remove any jewelryPosition the patient in a comfortable manner. Drape the body part so that only the area to be treated is exposedIf a moist heat treatment is desired, place a damp terry cloth towel over the area
43Place the lamp so that the source of heat is approx 24 inches away from the patient. Adjust the lamp so the energy will strike the tissues at a right angle (inverse square law)To prevent burns, instruct the patient not to moveCheck the patients comfort periodically. The intensity may be adjusted by moving the lamp toward the skin (increasing temp) or away from the skin (decreasing temp)Instruct the patient to summon assistance if the intensity of the treatment becomes too great
44Duration of treatment20-30 minutesGiven as needed
45Indications/contraindications Subacute or chronic inflammatory conditionsSkin infectionsPeripheral nerve injuries before electrical stimulationAnother modality should be considered if the patient lacks temp perceptionContraindicationsAcute conditionsPeripheral vascular diseaseAreas with sensory loss or scarringsunburns
46Shortwave Diathermy A deep-heating modiality Uses energy that is similar to broadcast radio waves but has a shorter wave lengthThe energy is delivered to the body is acutally a high-frequency alternating current, but lacks the properties needed to depolarize motor or sensory nerves.The Federal communication Commission has reserved the frequencies of 13.56, 27.12, and for medical use
47Structures with high water content, like adipose tissue, blood, and muscle, are selectively heated at depths of 2-5cm.Local tissue temp may reach 107°, but the subcutaneous fat layer dissipates a significant portion of the energyThis leads to a secondary heating of the superficial muscle layer by heat conducted from the adipose tissueThe amount of intramuscular temp increase compares favorably with that seen during ultrasound applicationProducing an increase of more than 7 degrees F
482 units that are commonly used Because of the relatively large area affected by diathermy, the deep heating effects are longer lasting than those experienced with ultrasoundHowever, it is less effective on those persons who have a large amount of subcutaneous fat.2 units that are commonly usedThe condenser unitThe conduction unit
49Condenser unitApplication by way of a condenser unit places the patient within the actual circuit of the machines unit2 insulated plates are place on either side of the site being treatedThe flow of electromagnetic energy passes through the tissues, which act as electrical resistors and produce frictional heatingHeating occurs at depths of cm but is uneven because of differences in the resistance to energy transportation of various tissuesWhen condenser plates or pads are used, heating tends to occur in the subcutaneous tissues and the superficial muscle layer
50Induction UnitDoes not place the patient directly in the units circuit.Tissues are affected by radiation emitted form the electromagnetic field created by the electrodeThe effects of the induction method may heat tissues up to 5cm beneath the skinBut the primary temp increase occurs in the superficial and middle muscle layers
51The tissues are place in the electromagnetic field by the use of an insulated cable electrode The cable may be wrapped around the extremity or coiled flat like a pancake and placed on the skinAnother method ahs the cable in a self-contained drum
52Effects on the IRCHeating properties are similar to those of other forms of heat applicationBut tend to occur deeper within the tissues and are based on the treatment intensityDuring vigorous heating skin temp in the treated area increases 4.3 degrees, and the intra-articular temp of the knee increases 2.5 degrees.Blood flow in the deeper tissues increases, and fibroblastic activity, collagen deposition, and new capillary growth are stimulated.
53Muscle spasm is reduced by the sedation of sensory and motor nerves As with all heat applications, there is a local increase in cellular metabolic rate and in perspiration, which must be removed during the treatment
54General prepThere must be no metal within the immediate treatment area. The presence of metal will collect and concentrate the energy from the treatment in the same manner that an antenna collects radio wavesFor personal safety, the clinician should remove any rings, watches, bracelets, and so onCover the area to be treated with a dry terry cloth towel to absorb perspiration. A portion of the treatment area must remain visible to check for burns during treatment. Avoid any moisture buildup during the treatment because water tends to collect heat. The intensity must be turned to “zero” before drying the area
55Condenser method Plate setup Adjust the plates so that they are parallel to the skin, 1 inch above the patient. On most units, it is essential that both plates be placed at an equal distance above the tissue. This adjustment can be accomplished by using a spacer, such as a piece of wood. Place the spacer on the patient and lower the plate until the plate and the spacer touch. Remove the spacer and repeat for the other plate. The spacer must be removed before the treatment is started.
56Consult the user’s manual for the minimum and maximum distance allowed between the condenser plates. Condenser pad setupCover the area to be treated with six layers of towelingPlace the condenser pads on the toweling. If the pads are used on the same side of the body, place them as far apart as possible. If they are used on the opposite side of the body part (anterior or posterior, medial or lateral), avoid having the patient lie on the padSecure the pads in place with sandbags or something like that.
57Induction Method Cable setup Place six layers of toweling around the body partUsing spacers, wrap the cable around the body part, leaving a minimum of 1” between the coils. The leads to and from the coil should be of equal lengthSecure the cable ends so that they do not touch each other, the patient, or the shortwave unit itself
58Coil setupUsing spacers, form a coil of at least three circles approximately equal to the area being treated. There should be a minimum of 1” between the circles, and the leads should be of equal length. Use an insulator or 1” of padding to separate the end of the inner coil from the coil itselfInsulate the skin with at least 6 layers of towelingPlace the coil on the patient and lightly secure in place with sandbagsPosition the leads so they do not come in contact with each other, the patient, or the unit.
59Drum setupPosition the drum approx .5-1” above the toweling. There is a direct relationship between the distance of the drum from the patient and the intensity of energy required for the treatment.
60Application Turn the unit on: allow it to warm up if necessary Some units must be turned to allow for maximal energy transfer. If tuning is necessary, consult the user’s manual and follow the manufacturer’s instructions.Instruct the patient not to move until the machine is turned off.Increase the intensity until the athlete feels mild warmth
61If the electrodes must be moved or if it becomes necessary to dry the area, return the intensity to zero before making any adjustmentsCheck patient regularly. Observe the skin for signs of burns, and inquire as to any unusual sensations. Adjust as necessaryAfter the treatment, return the intensity dial to “zero” and shut off the unit.
62Duration of treatmentAt moderate intensities, treatments may be given for minutes and may be repeated as needed for 2 weeks. When higher treatment temps are used, decrease the duration of treatment and apply on alternate days.
63PrecautionsMany states require a physician’s prescriptions for the application of SWD.Never allow the cables to touch each other. This may create a short circuitThe skin exposed to the treatment must always be covered by at least .5” of towelingDo not allow perspiration to collect in the treatment field
64Never allow the skin to come into direct contact with the heating unit or cables. Severe burns may result.Excessive amounts of adipose tissue overlying the treatment area can result in overheating the skinOverheating of the patients tissues may cause tissue damage without any immediate signs. Deep-tissue burning can cause destruction of muscular tissue of subcutaneous fat necrosis.A deep, aching sensation may be a symptom of overheating the tissues
65It is difficult to heat only localized areas It is difficult to heat only localized areas. Water pathways within the tissues dissipate heat formed in the treated areaThe electromagnetic energy is not localized to the treatment area, radiating 2 to 3 feet from the source of continuous SWD and 2 feet from the source of pulsed diathermy. Clinicians may be placed in the field of this scattering radiation, possibly overexposing them to diathermy. A distance of 3 feet from the source of the energy should be maintained to ensure the operator’s safety.
66IndicationsJoint inflammation (bursitis, tendinitis, synovitis) Use with caution as the deep heating may cause collagen destruction within the joint.Large areas, such as the paraspinal muscles, that cannot be effectively heated through other methods because of the size of the target tissuesFibrositisMyositisSubacute and chronic inflammatory conditions in deep-tissue layersosteoarthritis
67ContraindicationsIschemic areas: the increased metabolic rate increases the need for oxygen, causing further hypoxiaPeripheral vascular diseaseMetal implants or metals such as jewelry. The metal collects and concentrates the energy, potentially causing burnsPerspiration and moist dressings. The water collects and concentrates the heat
68Tendency to hemorrhage, including menstruation. Cancer Fever Sensory lossCardiac pacemakersAreas of particular sensitivityEpiphyseal plates in children, the genitals, sites of infection, the abdomen with an implanted intrauterine device (IUD), the eyes and face