hyperbaric chamber

Hyperbaric Chamber

Definition

A hyperbaric chamber is a room that allows an individual to breathe 100% pure oxygen at greater than 1 standard atmosphere of pressure.

Purpose

Hyperbaric chambers are used to deliver hyperbaric oxygen therapy (HBOT). HBOT was developed to treat underwater divers suffering from decompression sickness (the bends). It has since been approved by the Undersea and Hyperbaric Medical Society for 13 conditions including:

air or gas embolism
carbon monoxide (CO) poisoning
smoke inhalation
gas gangrene caused by certain bacteria
decompression sickness
radiation tissue damage
thermal burns
non-healing skin grafts
crush injuries
wounds that fail to heal through conventional treatment
serious blood loss
intracranial abscess.

Although hyperbaric therapy has become increasingly popular for other uses, especially in sports medicine, its use is controversial. Terrell Owens of the Philadelphia Eagles used HBOT for an ankle injury prior to playing in the Super Bowl in 2005, but medical professionals questioned the appropriateness of this treatment.

Precautions

Individuals who have lung disease including asthma, emphysema, obstructive lung disease, or any condition in which air is trapped in the lungs, are poor candidates for this therapy and should discuss the relative benefits and drawbacks of HBOT with their doctor. Individuals who have had chest surgery or who have had a central venous catheter implanted are also at higher risk for complications. People with seizure disorders should be carefully monitored, as this treatment may increase the risk and severity of seizures. People with colds or clogged ears may want to wait to undergo HBOT, as they may experience difficulties with pressure equalization that can cause damage to the middle or inner ear. HBOT in pregnancy is controversial. Individuals with diabetes may need to adjust their glucose and insulin balance, since HBOT slows the absorption of insulin.

Description

At normal atmospheric pressure, oxygen binds with a molecule in red blood cells called hemoglobin. The oxygen is carried through the body to tissues where it is needed as the blood circulates. Under normal conditions, almost all (about 97%) of the available hemoglobin carries oxygen. Increasing the atmospheric pressure does little to increase the oxygen-carrying capacity of the blood. However, under normal conditions, only a small amount of oxygen is dissolved in the fluid that carries the red blood cells (blood plasma). Increasing the atmospheric pressure to two to three times normal and breathing 100% oxygen forces more oxygen to dissolve into the blood plasma. In this way, hyperbaric chambers increase the amount of oxygen circulating in the body. This can promote healing in areas that are not receiving adequate oxygen. The extra oxygen can also help to cure certain infections caused by anerobic bacteria that can live only in the absence of oxygen.There are two types of hyperbaric chambers—monoplace and multiplace. Monoplace chambers accommodate a single person. The patient enters the chamber, then it is closed and the pressure is increased. The advantages of a monoplace chamber are that the patient does not have to wear a mask or a hood to receive the oxygen and the treatment regimen is designed specifically for each individual. The major disadvantages are that the patient is inaccessible to the staff during treatment should an emergency arise, and the pure oxygen atmosphere creates an increased fire hazard. In multiplace chambers, several patients use the same chamber simultaneously. Each person is given oxygen through a face mask or hood, but all patients receive the same treatment. A staff member remains in the chamber throughout the procedure.Hyperbaric chambers can be associated with hospitals, but are increasingly part of free-standing clinics. Insurance may cover the cost of treatment for approved indications such as carbon monoxide poisoning, but may reject payment for uses that are considered experimental or controversial. The American Board of Medical Specialists certifies physician competency in the undersea medicine, including the use of hyperbaric chambers. The Baromedical Nurses Association offers three levels of certification for hyperbaric nurses, and the National Board of Hyperbaric Medicine Technology certifies hyperbaric technicians. Individuals considering hyperbaric therapy should seek facilities run by health care providers credentialed by these organizations.

Preparation

No special preparation is needed to use a hyperbaric chamber other than educating patients about what to expect during treatment.

Aftercare

After HBOT is complete, a period of decompression in the chamber is required until the pressure in the chamber is equal to the pressure outside. Serious complications can occur if decompression occurs suddenly.

Risks

Hyperbaric chambers, because of their use of 100% oxygen, present a potential fire risk. In addition, although hyperbaric oxygen therapy is very safe when used correctly, complications can occur. Oxygen poisoning, also called oxygen toxicity, can occur when an individual is exposed to high doses of oxygen for a prolonged period. Excess oxygen causes chemical changes in the body that negatively affect cells and metabolic processes. Symptoms of oxygen poisoning include nausea, vomiting, dry cough, seizures, chest pain, sweating, muscle twitching, ringing of the ears, hallucinations, dizziness, shortness of breath and a decreased level of consciousness.Other complications can occur as the result of increased pressure within the chamber. These include pain and bloody discharge from congested sinuses, ear pain, rupture of the eardrum, and bleeding from the ear if the Eustachian tube that connects the ear to the back of the throat is clogged and pressure on either side of the eardrum is not equalized. Teeth that are infected or have been repaired may become painful or explode if gas is trapped within them. A few individuals develop pneumothorax. This is a serious condition where air is trapped between the lungs and the chest cavity.

Normal results

HBOT is expected to promote healing and improve the health of individuals with conditions for which it is approved.

Abnormal results

Under some conditions HBOT fails to cause improvement or complications occur.

Key terms

Embolism — An obstruction in a blood vessel, often caused by gas or a blood clot.Eustachian tube — A tube of cartilage that connects the middle ear to the back of the throat. Its purpose is to equalize the pressure on either side of the eardrum.

Resources

Organization

Undersea and Hyperbaric Medicine Society. 10531 Metropolitan Avenue, Kensington, MD 20895. 310-942-7804. 〈www.uhns.0rg〉.

Other

Moder, Cheryl. Hyperbaric Oxygen Therapy: Where Medicine Meets the Deep Blue Sea, 20 February 2005 [cited 20 February 2005]. http://www.emedicine.com/plastic/topic526.htm.Neumeister, Michael. Hyperbaric Oxygen Therapy, 11 November 2004 [cited 16 February 2005]. http://www.emedicine.com/plastic/topic526.htm.Prince, Mark. Hyperbaric Oxygen, 27 October 2004 [cited 16 February 2005]. http://www.emedicine.com/ent/topic733.htm.

chamber

[chām´ber] an enclosed space.

Chambers of the eye. From Dorland's, 2000.anterior chamber the part of the aqueous humor-containing space of the eyeball between the cornea and iris.counting chamber the part of a hemacytometer consisting of a microscopic slide with a depression whose base is marked in grids, and into which a measured volume of a sample of blood or bacterial culture is placed and covered with a cover glass. The number of cells and formed blood elements in the squares is counted under a microscope and used as a representative sample for calculating the unit volume.drip chamber the expanded portion of intravenous tubing into which fluid falls, where the rate of flow can be monitored if necessary. See also intravenous infusion.hyperbaric chamber an enclosed space in which gas (oxygen) can be raised to greater than atmospheric pressure; see also hyperbaric oxygenation.ionization chamber an enclosure containing two or more electrodes between which an electric current may be passed when the enclosed gas is ionized by radiation; used for determining the intensity of x-rays and other rays.posterior chamber that part of the aqueous humor–containing space of the eyeball between the iris and the lens.vitreous chamber the vitreous humor–containing space in the eyeball, bounded anteriorly by the lens and ciliary body and posteriorly by the posterior wall of the eyeball.