Sunday, 26 September 2010


A blanket-sized aquathermia pad, the hyperthermia-hypothermia blanket raises, lowers, or maintains body temperature through conductive heat or cold transfer between the blanket and the patient. It can be operated manually or automatically.


Hyperthermia-Hypothermia Blanket

In manual operation, the nurse or physician sets the temperature on the unit. The blanket reaches and maintains this temperature regardless of the patient's temperature. The temperature control must be adjusted manually to reach a different setting. The nurse monitors the patient's body temperature with a conventional thermometer.
In automatic operation, the unit directly and continually monitors the patient's temperature by means of a thermistor probe (rectal, skin, or esophageal) and alternates heating and cooling cycles as necessary to achieve and maintain the desired body temperature. The thermistor probe also may be used in conjunction with manual operation but isn't essential.
The unit is equipped with an alarm to warn of abnormal temperature fluctuations and a circuit breaker that protects against current overload.
The blanket is most commonly used to reduce high fever when more conservative measures—such as baths, ice packs, and antipyretics—are unsuccessful. Its other uses include maintaining normal temperature during surgery or shock; inducing hypothermia during surgery to decrease metabolic activity and thereby reduce oxygen requirements; reducing intracranial pressure; controlling bleeding and intractable pain in patients with amputations, burns, or cancer; and providing warmth in cases of severe hypothermia.
Hyperthermia-hypothermia control unit • operation manual • fluid for the control unit (distilled water or distilled water and 20% ethyl alcohol) • thermistor probe (rectal, skin, or esophageal) • patient thermometer • one or two hyperthermia-hypothermia blankets • one or two disposable blanket covers (or one or two sheets or bath blankets) • lanolin or a mixture of lanolin and cold cream • adhesive tape • towel • sphygmomanometer • gloves, if necessary • optional: protective wraps for the patient's hands and feet.
Disposable hyperthermia-hypothermia blankets are available for single-patient use.
Preparation of equipment
First, read the operation manual. Inspect the control unit and each blanket for leaks and the plugs and connecting wires for broken prongs, kinks, and fraying. If you detect or suspect malfunction, don't use the equipment.
Review the physician's order, and prepare one or two blankets by covering them with disposable covers (or use a sheet or bath blanket when positioning the blanket on the patient). The cover absorbs perspiration and condensation, which could cause tissue breakdown if left on the skin. Connect the blanket to the control unit, and set the controls for manual or automatic operation and for the desired blanket or body temperature. Make sure the machine is properly grounded before plugging it in.
Turn on the machine and add liquid to the unit reservoir, if necessary, as fluid fills the blanket. Allow the blanket to preheat or precool so that the patient receives immediate thermal benefit. Place the control unit at the foot of the bed.
  • Assess the patient's condition, and explain the procedure to him. Provide privacy, and make sure the room is warm and free of drafts. Check facility policy and, if necessary, make sure the patient or a responsible family member has signed a consent form.
  • Wash your hands thoroughly. If the patient isn't already wearing a patient gown, ask him to put one on. Use a gown with cloth ties rather than metal snaps or pins to prevent heat or cold injury.
  • Take the patient's temperature, pulse, respirations, and blood pressure to serve as a baseline, and assess his level of consciousness, pupil reaction, limb strength, and skin condition.
  • Keeping the bottom sheet in place and the patient recumbent, roll the patient to one side and slide the rolled blanket halfway underneath him, so that its top edge aligns with his neck. Then roll the patient back, and pull and flatten the blanket across the bed. Place a pillow under the patient's head. Make sure his head doesn't lie directly on the blanket because the blanket's rigid surface may be uncomfortable and the heat or cold may lead to tissue breakdown. Use a sheet or bath blanket as insulation between the patient and the blanket.
  • Apply lanolin or a mixture of lanolin and cold cream to the patient's skin where it touches the blanket to help protect the skin from heat or cold sensation.
  • In automatic operation, insert the thermistor probe in the patient's rectum and tape it in place to prevent accidental dislodgment. If rectal insertion is contraindicated, tuck a skin probe deep into the axilla, and secure it with tape. If the patient is comatose or anesthetized, insert an esophageal probe. Plug the other end of the probe into the correct jack on the unit's control panel.
  • Place a sheet or, if ordered, the second hyperthermia-hypothermia blanket over the patient. This increases the thermal benefit by trapping cooled or heated air.
  • Wrap the patient's hands and feet if he wishes to minimize chilling and promote comfort. Monitor vital signs and perform a neurologic assessment every 5 minutes until the desired body temperature is reached and then every 15 minutes until temperature is stable or as ordered.
  • Check fluid intake and output hourly or as ordered. Observe the patient regularly for color changes in skin, lips, and nail beds and for edema, induration, inflammation, pain, and sensory impairment. If they occur, discontinue the procedure and notify the physician.
  • Reposition the patient every 30 minutes to 1 hour, unless contraindicated, to prevent skin breakdown. Keep the patient's skin, bedclothes, and blanket cover free of perspiration and condensation, and reapply cream to exposed body parts as needed.
  • After turning off the machine, follow the manufacturer's directions. Some units must remain plugged in for at least 30 minutes to allow the condenser fan to remove water vapor

    from the mechanism
    . Continue to monitor the patient's temperature until it stabilizes because body temperature can fall as much as 5° F (2.8° C) after this procedure.
  • Remove all equipment from the bed. Dry the patient and make him comfortable. Supply a fresh patient gown, if necessary. Cover him lightly.
  • Continue to perform neurologic checks and monitor vital signs, fluid intake and output, and general condition every 30 minutes for 2 hours and then hourly or as ordered.
  • Return the equipment to the central supply department for cleaning, servicing, and storage.
Special considerations
  • If the patient shivers excessively during hypothermia treatment, discontinue the procedure and notify the physician immediately. By increasing metabolism, shivering elevates body temperature.
  • Avoid lowering the temperature more than 1 degree every 15 minutes to prevent premature ventricular contractions.
  • Don't use pins to secure catheters, tubes, or blanket covers because an accidental puncture can result in fluid leakage and burns.
  • With hyperthermia or hypothermia therapy, the patient may experience a secondary defense reaction (vasoconstriction or vasodilation, respectively) that causes body temperature to rebound and thus defeat the treatment's purpose.
  • If the patient requires isolation, place the blanket, blanket cover, and probe in a plastic bag clearly marked with the type of isolation so that the central supply department can give it special handling. If the blanket is disposable, discard it, using appropriate precautions.
  • To avoid bacterial growth in the reservoir or blankets, always use sterile distilled water and change it monthly. Check to see if facility policy calls for adding a bacteriostatic agent to the water. Avoid using deionized water because it may corrode the system.
  • To gradually increase body temperature, especially in postoperative patients, the physician may order a disposable warming system. (See Using a warming system.)
Use of a hyperthermia-hypothermia blanket can cause shivering, marked changes in vital signs, increased intracranial pressure, respiratory distress or arrest, cardiac arrest, oliguria, and anuria.
Record the patient's pulse, respirations, blood pressure, neurologic signs, fluid intake and output, skin condition, and position change. Record the patient's temperature and that of the blanket every 30 minutes while the blanket is in use. Also document the type of hyperthermia-hypothermia unit used; control settings (manual or automatic and temperature settings); date, time, duration, and the patient's tolerance of treatment; and signs of complications.