CHAPTER 8 Superficial Cold and Heat

Week 2 + CHAPTER 8: Superficial Cold and Heat

Prepared by: Sherman Mercado

CHAPTER 8: Superficial Cold and Heat

Prepared by: Michelle H. Cameron

Introduction to Cryotherapy and Thermotherapy

• Classification:

  • Deep vs. Superficial

    • Basis of application and depth of temperature change.

• Superficial Cooling/Heating Agents:

  • Conduction: Cold packs, hot packs, paraffin wax.

  • Convection: Whirlpool therapy, Fluidotherapy.

  • Radiation: Infrared lamps.

• Note: Deep-heating agents (e.g., ultrasound, diathermy) are not covered.

  • Focus on superficial heating agents in this chapter.

Cryotherapy

Definition and Clinical Applications

• Cryotherapy: Use of cold for therapeutic purposes.

  • Applications include rehabilitation and tissue destruction (benign/malignant).

• Whole-body therapeutic hypothermia:

  • Used post-cardiac arrest, severe stroke, or neurological trauma.

  • Target Body Temperature: 32°C to 35°C (89.6°F to 95°F).

  • Benefits include decreased tissue temperature and muscle soreness prevention.

Effects of Cold

Hemodynamic Effects

Initial Decrease in Blood Flow

• Mechanism: Initial cold application causes:

• Vasoconstriction of skin vessels.

• Reduced blood flow (approx. 40% decrease) in applied area.

• Lasting effects during and after cooling session.

Mechanisms of Vasoconstriction:

• Activation of cold receptors; increase in blood viscosity; reduced release of vasodilators (e.g., histamine, prostaglandins).

• Reflex activation of sympathetic neurons leading to regional vasoconstriction.

Temperature Regulation

Body Response to Cold

• Body decreases blood flow in response to cold to protect core temperature and prevent excessive cooling of tissues.

• Increased localized cooling leads to reduced circulation elsewhere in the body.

Later Increase in Blood Flow

• Cold-Induced Vasodilation (CIVD):

  • Occurs when cooling extends over periods or tissue temperature falls below 10°C (50°F).

  • First reported by Sir Thomas Lewis (1930); cyclic temperature changes occur after prolonged cold exposure.

  • Phenomenon mediators include:

    • Axon reflex due to pain from prolonged cold.

    • Reflexive vasodilation response in distal extremities, primarily fingers and toes.

Neuromuscular Effects of Cold

Decreased Nerve Conduction Velocity

• Nerve conduction velocity decreases due to reduced temperature; effects vary based on time and duration of cooling.

• Recovery time after cooling is relatively quick (15-30 minutes).

Pain Reduction Mechanisms

• Cold application activates gate control mechanisms, reduces muscle spasm, and overall decreases post-injury edema.

Muscle Strength Changes

• Isometric muscle strength may increase:

  • After brief cooling but decrease with prolonged cooling (over 15 minutes).

  • Strength assessment recommended before cryotherapy.

Decreased Spasticity

• Cryotherapy can briefly reduce spasticity and alter stretch reflexes.

• Longer applications (10-30 min) can lead to sustained effects on muscle tone, useful during therapeutic activities.

Facilitation of Muscle Contraction

• Brief cryotherapy can trigger alpha motor neuron activity assisting in muscle contraction in cases of flaccidity.

Metabolic Effects of Cold

Decreased Metabolic Rate

• Cryotherapy slows metabolic reactions, beneficial for inflammation control but should be used cautiously if healing is delayed.

Clinical Indications

Inflammation Control

• Reduces inflammation symptoms: heat, redness, edema, pain, and function loss within tissue healing phases.

• Counteracts microvascular damage from inflammation.

Edema Control

• Effective immediately post-acute trauma combined with compression and elevation.

Pain Control

• Modifies sensation through direct cold effects and by addressing underlying causes (e.g., inflammation).

Clinical Indications for Cryotherapy

Spasticity Modification

• Brief cold applications reduce deep tendon reflexes, while longer applications can eliminate clonus.

Multiple Sclerosis (MS)

• Patients may present heat sensitivity; controlled cooling alleviates symptoms.

Contraindications for Cryotherapy

• Cold hypersensitivity, intolerance, cryoglobulinemia, Raynaud’s phenomenon, and over areas with circulatory compromise or regenerating nerves.

Specific Conditions

• Cold hypersensitivity: Itchy, red patches; cold intolerance may result in pain and numbness.

• Raynaud’s: Characterized by vasospasm and skin color changes.

Precautions for Cryotherapy

• Apply caution in patients with impaired sensation or at extremes of age; monitoring for adverse effects is critical.

Application Techniques

General Cryotherapy

• Tools include cold packs, ice cups, contrast baths. Sequence of sensations: cold > burning > aching > numbness.

Specific Techniques

• Ice massage: 5-10 minutes; useful in motor pattern facilitation.

• Controlled cold compression units: Effective in cooling and assisting recovery.

Vapocoolant Sprays

• Used before stretching for myofascial pain syndromes.

Thermotherapy: Heat Application

Effects of Heat

Hemodynamic Effects

• Vasodilation increases blood flow, impacts distal cutaneous vessels, and stimulates thermoreceptors.

Neuromuscular Effects

Changes in Nerve Conduction Velocity

• Increases speed of nerve conduction; may reduce pain perception.

Clinical Indications for Superficial Heat

• Relief for joint stiffness, increased range of motion, pain control via sensory pathways, and assistance in healing processes.

Precautions and Contraindications

• Avoid in recent hemorrhage, thrombosis, impaired sensation, etc.

Adverse Effects of Thermotherapy

Burns and Tissue Damage

• Protein denaturation at high temperatures can lead to cell death; ensure proper application duration and monitoring.

Documentation of Cryotherapy and Thermotherapy

• Essential to record treated areas, type of agent, duration, and patient response.

Example Documentation

• Detailed records of interventions, patient symptoms, and outcomes are crucial for ongoing treatment planning.