Heat and cold applications promote offer comfort by reducing tissue swelling and promote healing and are ordered to relieve pain, fight local infection, swelling, or inflammation, control bleeding, and reduce body temperature (Acello & Hegner, 2021). Regulated healthcare professionals (nurses, physiotherapists, physicians) use heat and cold applications to reduce tissue swelling and promote healing and comfort for injuries and post-operations. Even though heat and cold are effective interventions, there are risks associated with these. Therefore, hot and cold applications should only be used if part of the client’s care plan and only for a specific length of time. Some facilities allow only professional personnel to apply heat and cold, so be sure to follow the agency policies. HCAs should only apply if the task has delegated to them by the RN.

Hot and Cold Effects

Think back to a time when you were really hot and you started sweating and your fingers were swollen. Now think about a time when you were really cold and you started to shiver and maybe your lips turned a little blue. What you experienced are the effects of heat and cold. Heat and cold have opposite effects on body functions. Heat increases blood flow by vasodilating blood vessels. When heat is applied to an area, the blood vessels in that area will dilate to increase blood flow (Fig. 1). However, when cold blood flow is slowed by vasoconstricting blood vessels to conserve body heat (Fig. 1). Applying a cold pack to an area will constrict blood flow in that area to reduce swelling.

An aquathermia pad is a pad with tubes inside. The pad is attached to a cooling/heating unit with two hoses. The cooling/heating unit is filled with distilled water to bring to desired temperature. The water flows through one of the hoses and into the tubes in the pad. Then the water flows through the other hose and back into the cooling/heating unit to maintain the desired water temperature before flowing back into the pad.

4. Hot Pack

Hot packs can be hot water bags, heating pads, and hot aquamatic pads.   Some hot packs are filled with hot fluid. Hot packs may be heated by heating them in the microwave or in hot water or by striking or squeezing them to activate chemicals. Hot packs are applied to the area of the body being treated. They may be reusable or disposable. The water temperature of a hot pack should not exceed 110°F, or 43°C.  A hot pack such as an electric heating pad or an aquathermia pad, which produces dry heat, is used to treat muscle sprains and mild inflammations and for pain relief. K-pads use Temperature-controlled, distilled water that flows through the waterproof pad. The water temperature of a hot aquamatic pad is typically 95° to 105°F, or 35° to 41°C (Acello & Hegner, 2021; Sorrentino, et al., 2019). 

5. Warm Compresses

Description automatically generated Compresses such as 4 X 4 gauze or Telfa pads, are used to apply moist heat to a small area. Large warm, moist packs of cotton or terry cloth are used to apply heat over a larger area. Commercially prepared warm packs are also available and may be used to apply either dry or moist heat. Covering any hot pack with heavy, dry material helps it retain heat longer. Application of an Aqua-K pad over a pack enables the pack to remain heated almost indefinitely. The water temperature of a hot compress is typically 100° to 105°F, or 38° to 41°C. Compresses and hot packs are usually not sterile. However, if there is a break in the client’s skin, sterile dressings may be used (Acello & Hegner, 2021; Sorrentino, et al., 2019). 

6. Hot Soak

A hot soak is a type of moist heat application that consists of immersing the client’s affected body part in warm water or medicated solution for a prescribed time. The area of the body being treated is placed in a basin filled with hot water.  The water temperature of a hot soak is typically 105° to 120°F, or 41° to 49°C (Acello & Hegner, 2021; Sorrentino, et al., 2019). 

7. Sitz Bath

A sitz bath is a type of moist heat application. The pelvic, perineal, and rectal areas of the body are placed in hot water. The water temperature of a sitz bath is typically 105°F, or 41°C. Disposable sitz basins are often used or a regular bathtub with enough water to cover the client’s hips and perineum (Acello & Hegner, 2021; Sorrentino, et al., 2019). 

Heat Applications

Heat relieves pain, relaxes muscles, promotes healing, reduces tissue swelling, and decreases joint stiffness. When heat is applied to the skin blood vessels in the area dilate. Blood flow increases bringing more oxygen and nutrients to the surrounding tissue for healing. The vasodilation allows for excess fluid to be removed from the area faster. On observation, the skin will be red and warm to the touch (Acello & Hegner, 2021; Sorrentino, et al., 2019).  Heat applications are also comforting. And the sensation of heat may decrease the transmission of pain signals to the brain which can relieve pain and discomfort. In addition, heat applications relax muscles and joints which can decrease stiffness. Heat applications are used for chronic, or ongoing, conditions. These include back pain and arthritis. Heat applications may also be used only after the first two to three days following an acute, or sudden, injury (Acello & Hegner, 2021).

There are two types of heat applications: Dry and moist. Dry heat applications are dry against the skin and no water touches the skin. Dry heat applications include hot packs, hot water bags, heating pads, and hot aquathermia pads. A dry application stays at the desired temperature longer. Moist heat applications are moist against the skin where the moisture or water touches the skin. Moist heat applications include hot compresses, hot soaks, and sitz baths. Moist heat applications Moist heat has greater and faster effects and are more penetrating than dry heat applications (Acello & Hegner, 2021; Sorrentino, et al., 2019). 

Complications

High temperature can cause burns (See Table 13.2.1). When heat is applied too long, blood vessels will start to constrict. Persons at risk for complications include older adults, fair-skinned persons, those with decreased sensation to heat and pain. Persons with dementia and those who have metal implants are also at risk for injury. Others at risk for complications include:

COLD APPLICATIONS

Cold applications are used for acute or sudden injuries such as treat sprains, fractures, or fevers and are therefore useful right after an injury. Cold applications have numbing effect so relieves or reduces pain. When the blood vessels vasoconstrict blood flow to the area and as a result, less blood is able to come to the area. This in turn, decreases bleeding and reduces swelling. Cold is applied during the first two to three days following an injury.

There are two types of cold applications: Dry and moist. Dry cold applications are dry against the skin and no water touches the skin. Dry cold applications include cold packs, ice bags, and cold aquathermia pads. Moist heat applications are moist against the skin where the moisture or water touches the skin. Moist cold applications include cold compresses and cold soaks. Moist cold applications are more penetrating than dry cold applications (Acello & Hegner, 2021; Sorrentino, et al., 2019). 

Complications

Cold temperature can cause burns, pain, blisters, and poor circulation (See Table 13.2.1 above). When cold is applied for a long time, blood vessels dilate; this occurs as the body tries to warm the body temperature. Persons at risk for complications include older adults,  fair-skinned persons, those with decreased sensation to heat and pain. Persons with dementia and those who have metal implants are also at risk for injury. Others at risk for complications include:

Loss of consciousness

• Scarring of the skin
• Use of some medications
• Spinal cord injuries
• Stroke
• Diabetes
• Aging, which can cause decreased sensations due to changes in body function
• Clients with dementia or confusion
• Clients with metal implants (pacemaker, joint replacement)

A Word about Hypo- and Hyperthermia

Hypothermia is when the core body temperature drops below 35°C. While hyperthermia is when the core body temperature is excessively higher than normal. Under normal circumstances, the body is able to maintain its core body temperature within 1°C of 37°C. These excessively high or low body temperatures are managed and treated in acute care facilities. Hypothermia-hyperthermia blankets (Aquathermia blankets) are placed over and under the clients to maintain temperature regardless of changes in the client’s body temperature. The healthcare team monitors the client’s temperature through a rectal, skin, or esophageal probe with the goa to maintain body temperature (Acello & Hegner, 2021).

Role of an Assistant Health Care Assistants in Cold and Heat Applications

When performing cold and heat applications, HCAs must follow the client’s care plan. Specifically, HCAs need the following information:

In some health authorities and agencies, only physicians, therapists, and nurses may perform cold and heat applications. Health care assistants should only perform cold and heat applications if their agency permit them to do so. While performing a cold or heat application, HCAs must immediately report any problems to their supervisor. After performing a cold or heat application, HCAs must report and document all of the actions taken, including any observations and if the application resulted in pain relief, decreased stiffness, or reduced swelling.

Any client receiving a heat or cold application should be frequently checked for any signs of problems related to their use. Inspect the skin beneath the application frequently, according to the care plan. It is advisable to check the skin every 5 minutes for the first two checks, and at least every 15 minutes after that (Sorrentino et al., 2013)). Because not every client may report having any discomfort, you should be particularly aware of signs such as restlessness, agitation, or other changes in behaviour and when performing cold and heat applications, HCAs must follow these guidelines (Acello & Hegner, 2021; Sorrentino, et al., 2019):

• Make sure the application is the temperature authorized in the client’s care plan
• Never place an application directly on a patient’s skin. Protect skin with a cloth as appropriate
• Check the patient frequently.   If skin discoloration, swelling, or blisters occur, remove the application and tell the supervisor immediately.
• If patients complain of discomfort, pain, or numbness, remove the application and tell the supervisor immediately.
• If patients complain of weakness, dizziness, drowsiness, or faintness, remove the application and tell the supervisor immediately.
• Apply the application only for the amount of time authorized in the patient’s care plan.

Because heat and cold applications produce different effects, HCAs must thoroughly understand the purposes, effects, and complications of these applications. There are  risks involved, some employers allow only nurses to do the heat and cold applications. You, as the HCA, must be certain that this is within your scope of practice for the agency you work for.

• Your employer’s policies allow you to perform the procedure
• The procedure is in your job description
• Apply only when ordered by a professional and allowed by your employer, and you are assigned to do so.
• You have the necessary training (Delegation of Task)
• You are familiar with the equipment
• You have reviewed the procedure with the RN
• An RN is available to answer questions and to supervise you
• Measure the temperature of moist applications before applying, according to your employer policy
• Follow employer policies for safe temperature ranges.
• Do not apply hot applications above 41.1°C (106°F) because tissue damage can occur. Only a nurse can apply a very hot application
• Confirm what the temperature of the application should be
• Know the precise site of the application
• Cover dry heat or cold applications with cloth before applying them. Use a flannel or terrycloth cover, towel, or pillowcase, according to your employer policy.
• Do not leave clients at risk unattended
• Observe the client’s skin, at least every 5 minutes, for signs of complications
• Observe for changes in the client’s behaviour, which may indicate the client is in pain
• Remind the client not to change the temperature of the application
• Ask your supervisor how long to leave the application in place. Carefully watch the time. Heat and cold are applied for no longer than 15-minute periods.
• If it is safe to leave, place the call bell within the client’s reach, or remain within easy hearing distance
• Follow Standard Practicesmoved after 20 minutes?

Acello, B., & Hegner, B. (2021).  Nursing Assistant: A Nursing Process Approach, 12th ed. Cengage. 

Sorrentino, S., Remmert, L., & Wilks, M. (2019). Mosby’s Canadian textbook for the support worker (4th ed.).