Thermal Biophysical Agents Overview

Thermal Biophysical Agents Study Notes

• Healing Phases: Three phases of healing follow injury:
  • Initial Injury/Inflammation (up to 48 hours): Characterized by vasoconstriction followed by vasodilation, hemostasis, and phagocytosis. Focus on preventing further injury, minimizing inflammation, pain, and functional deficits through passive care.
  • Proliferative Phase (1-2 weeks): Fibroblast arrival, epithelialization, collagen production, closure, and revascularization are key processes. Active care focusing on increasing circulation, cellular metabolism, range of motion, and movement ease is critical.
  • Maturation Phase (up to 1 year): Focus shifts to collagen balance (synthesis and lysis), and collagen remodeling. Active care with increasing load and intensity are used for increasing circulation, cellular metabolism, range of motion, and movement ease.

Cryotherapy

• Mechanism of Action: Transfer of heat through conduction, convection, and evaporation.
• Types:
  • Conduction: Ice massage, cold packs, ice immersion.
  • Convection: Cold immersion baths.
  • Evaporation: Cooling spray.
• Indications (First 24-48 hrs): Pain reduction; decrease edema; muscle relaxation; secondary hypoxic tissue injury prevention, post-operative situations. Ice massage targets myofascial trigger points..
• Contraindications: Cold hypersensitivity (urticaria), cold intolerance, cryoglobulinemia (vascular blockage).
• Precautions: History of Hypertension (HTN), thermoregulatory conditions (MS), open wounds requiring caution around infection. Poor circulation, impaired cognition, young/old, cold aversion. Consider tissue regeneration & vascular compromise.
• Progression of Sensation: Cold, burning, aching, analgesia (numbness).
• Duration: 10-30 minutes, with 20 minutes on, cooling 2cm deep. Ice massage: 5-10 minutes. Cold bath: 15-20 minutes.
• Objective Measures: Edema; Pain (NPRS); ROM; Function ("show me the task"); muscle guarding assessments.
• Risk Factors: Age (65+), Diabetes Mellitus, and poor sensation are high risk factors for burns. Precaution- cognitive impairment.

Thermotherapy

• Mechanism of Action: Conduction, convection, radiation, conversion, and evaporation transfer of energy.
• Contraindications: Recent/potential hemorrhage, DVT, Impaired sensation, Vascular insufficiency, Impaired cognition, malignancy, untreated infection.
• Precautions: Acute injury/inflammation, pregnancy, impaired circulation/thermal regulation, edema, open wounds, cardiac conditions, topical counter irritants, demyelinated nerves.
• Effect on Delayed-Onset Muscle Soreness (DOMS): Reduced eccentrically induced DOMS by 30 minutes post-heat application compared to cold and control groups.
• Effects on Strength & Endurance: Short burst heat (diathermy, whirlpool) may transiently reduce isometric strength followed by improvement over time.
• Temperature Elevation: Greater for skin/subcutaneous tissue (0.5-2cm) than muscle (1-2cm). Adipose influences sensitivity.
• Tissue Damage Threshold: Tissue damage begins at 113°F.
• Paraffin Baths: Low melting point (129°F), 8-10 dips, 15-20 min; safer than moist heat.
• PEACE & LOVE: Framework for managing musculoskeletal injuries: P-protection, E-elevation, A-avoid anti-inflammatories/ice, C-compression, E-education; and L-load, O-optimism, V-vasculature, E-exercise