Superficial heat: Conductive and Conversive agents

1. How do hot packs work? How long should they be applied for? What are the advantages and disadvantages?
2. What is a Kenny pack?
3. What is the peak temperature for a heating pad? What is the risk when used with moist towels?
4. What is a paraffin bath? What is it used for?
5. What are three methods for using paraffin baths?
6. What is radiant heat? Who is it most useful in? What are precautions to radiant heat?

Answers:
1. A hot pack such as a hydrocollator is a canvas bag filled with silicon dioxide immersed in tanks of heated water. It is a conductive agent. It is applied for 30 min, over several layers of insulated towels. Advantages are that it's low cost, requires minimal maintenance, and ease of use. Disadvantages include skin mottling with prolonged use (erythema abigne), characterized by reticular pigment and telangiectasia.
2. A Kenny pack is a wool cloth soaked in 60C water, then spun dried.
3. A heating pad is a conductive agent with circulating heated fluid such as water. Peak temperature is 52C. If used with most towels, there can be an electric shock.
4. A paraffin bath is a conductive agent, using paraffin wax and mineral oil in a 6-7:1 ratio. It is common used in irregular surfaces such as distal extremities and have been helpful with contractures, RA, and scleroderma.
5. Dipping is most common and involves placing body part in paraffin bath, then remove and allow wax to harden, then insulate wax for 20-30 mins. Immersion involves serial dips done to form a thin glove, followed by immersion in bath for 30 mins. Brushing involves using a brush to apply paraffin to larger body parts.
6. Radiant heat such as infrared lamps is a conversive agent in which energy is absorbed through the skin and converted to superficial heat. It is used in patients who can't tolerate heat packs. Precautions include general heat precautions, light sensitivity, skin drying, and photosensitive medications.