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Hyperbaric Oxygen Therapy
AORN J O U R N A L
JUNE 1988, VOL. 47, NO 6
Hyperbaric Oxygen Therapy A GUIDE FOR THE PERIOPERATIVE NURSE
Michelle Glowacki, R N Norma Chew, RN
H
yperbaric oxygen (HBO) therapy, which is the administration of 100% oxygen by inhalation within a chamber with greater than atmospheric pressure, was developed to relieve “the bends” experienced by deepsea divers. It has been more than 20 years since the therapy made a mark on the medical field, and its acceptance as an effective mode of treatment for various conditions is apparent by the fact that more medical centers in the United States are providing HBO therapy facilities for those patients it will benefit. At Jackson Memorial Hospital, Miami, HBO therapy is used in the otolaryngology, oral and maxillofacial surgery, orthopedic surgery, plastic and reconstructive surgery, general surgery, and medical departments. More than 1,600 “dives” were administered to a total of more than 100 patients between January 1987 and December 1987. HBO therapy is used spedically for problem wounds and help in the healing process, according to an oral surgeon at that hospital. He emphasizes that the therapy will not accelerate normal healing, but when it is used in conjunction with debridement and/or reconstructive surgery, it enhances healing (Fig 1). Another physician claims that one of the keys to success in HBO therapy is the physician’sjudgment in selecting patients who will benefit from treatment. The bends and problematic wounds will remain the two major uses of HBO therapy, but with more research and experimental studies, it could be used in other areas such as sports medicine, and spinal cord and head injuries, he said. In the future, HBO therapy will be a more defined, quantitative, sophisticated mode of treatment. 1370
This article addresses the indications, patient selection and preparation,risks, and mt-effectiveness of HBO therapy. The basic principles of HBO therapy can be explained with three laws of physics. Henry’s law: At a given temperature, the amount of gas that will dissolve in a liquid is directly proportional to the pressure of the gas. Under such great pressure, then, HBO therapy saturates plasma with oxygen. Dalton’s law: The total pressure of a mixture of gases is the sum of the partd pressure of each of the gases. Oxygen administered at 3 atmospheres absolute (ATA) would, therefore, produce a partial pressure of oxygen (PO3 of approximately 2,000 mm Hg.’ Michelle Glowacki, RN,BSN, CCRN, is an RN II in the department of anesthesia, division of hyperbaric and aquatic medicine, Jackson Memorial Hospital, Miami. She earned her associate of arts degree in general studies from the University of South Florida, Tampa, and her bachelor of science degree in nursingfrom Florida State University, Tallahassee. Norma Chew,RN,is a specialty coordinatorfor ear, nose, and throat and plastic surgety, Jackson Memorial Hospital, Miami She has a diploma in nursing from Kingston Public Hospital School of Nursing, Kingston, Jamaica, West Indies.
The authors acknowledge Jeffrey Hartog, MD, for his support and input.
JUNE 1988, VOL. 47. NO 6
AORN JOURNAL
Fig 1. A 68-year-old woman with a history of insulin dependent diabetes mellitus had a cut on her hand that healed very slowly. The photo (above) shows her hand after surgical debridement and three HBO treatments and (right) after 20 HBO treatments when the wound is completely healed.
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AORN JOURNAL
Hyperbaric oxygen therapy is used with antibiotics and surgery to enhance healing. Boyle’s law: At a constant temperature, the volume of a gas is inversely proportional to its pressure. The use of HBO, therefore, will result in a reduction of bubble size, as in the case of decompression sickness or arterial gas embolism.
Indications
H
yperbaric oxygen therapy has been used for many years and is indicated for various conditions. It is used in conjunction with antibiotic therapy and surgery to enhance the healing process of patients with radiation necrosis of the bone and soft tissue, gas gangrene, and skin ulcers of diabetes? Decompression sickness. Hyperbaric oxygen therapy is used for treating decompression sickness (DCS). In modern times, DCS is associated almost exclusively with underwater diving. Historically, DCS was known as the “bends” or caisson disease and was first described in workers building bridges in underwater airtight containers called caissons. Workers would experience joint pain after surfacing that developed into a flexed and contorted posture-the bends? Decompression sickness is caused by the formation of bubbles in the tissue during the ascent phase of a dive, after inspiration of inert gases under pressure. A rapid or emergency ascent, or failure to comply with standard decompression tables, may result in DCS in divers. The HBO treatment reduces bubble size and accelerates counterddbion, forcing oxygen into the cells and inert gases (often nitrogen) out4 Immediately after ascending from a deep sea dive, a patient may be unconscious. He or she also may experience joint pain, paresthesias, dyspnea, or even paralysis several hours after a dive. If the patient is unresponsive, emergency treatment must be initiated. Establishing a patent airway and kgumng cardiopulmonary resuscitation is vital before transporting the patient to a hyperbaric facility for 1374
compression. The patient should be placed in a leftsidedown reverse Trendelenburg position if possible. If the patient must be transported via aircraft, a cabin pressurized to sea level will prevent exacerbation of DCS symptoms. Once the patient is safely transported to the hyperbaric facility, he or she is placed inside the chamber and the “dive” (compression) is initiated. Depending on the patient’s condition, he or she is gradually decompressed according to standard diving decompression tables. Carbon momx& intoxication. Hyperbaric oxygen therapy also is indicated in treating carbon monoxide (CO) intoxication, which occurs after prolonged exposure to CO. Carbon monoxide is a colorless, odorless gas which is a product of incomplete combustion of hydrocarbon compounds. It is toxic and cam asphyxiation and hypoxia. Expure to CO commonly is c a d by fumes 60m a fire or exhaust fumes from an internal combustion engine. Early clinical signs and symptoms include headache and vertigo, and because these symptom are attributed to a multitude of other disorders, it is important to determine exposure to CO. The CO molecule has an affinity 200 times greater than that of oxygen to attach to the hemoglobin molecule? It binds with hemoglobin, forming carbxyhemoglobin (COHb). This leaves less 6ee hemoglobin available for oxygen transport to body tissues. The CO molecule also has been found to combine with the cytochrome a3 oxidax in the mitochondria of the cell, blocking cellular metabkm.6 Hyperbaric oxygen therapy is indicated for treating carbon monoxide intoxication because it speeds the release of CO from the hemoglobin and maintains sufficientoxygenation of body tissue and vital organs by hyperoxygenating the plasma. If untreated, after apparent complete recovery from CO intoxication, the exposed individual may exhibit some neurological dysfunction such as dementia or extrapyramidal symptoms
AORN JOURNAL
JUNE 1988, VOL. 47, NO 6
It is important to remember that hyperbaric oxygen therapy is an adjunctive therapy.
several days after exposure.’ It is important, therefore, to treat any person who shows signs of any type of cerebral dysfunction (eg, headache, loss of consciousness) regardless of COHb level. Arterial gas embolism. Hyperbaric oxygen therapy can be used to treat arterial gas embolism by reducing the bubble size (Boyle’s law). This embolism can result from barotrauma, a pulmonary overpressure accident caused by the patient holding his or her breath on the ascent phase of a dive, or if pulmonary gas trapping ( as in bronchospasm due to asthma) occurs at depth. A pulmonary overpressure accident can result in a tension pneumothorax, pneumomediastinum, and/or subcutaneous emphysema. In the event of a tension pneumothorax, immediate medical intervention and insertion of a chest tube is necessary. Arterial gas embolism also may be iatrogenic. For example, it may occur after air has been introduced into the coronary circulation during cardiac surgery. It also can result from the introduction of air into the extracorporeal circulation during arteriography studies or hemodialysis. Gas gangrene. When tissue is infected with Clostridim pefingem, which is found in soil and in the gastrointestinal tract, gas gangrene may occur. Cpe@ngem produces an alpha exotoxin that causes tissue necrosis. The diagnosis usually is made after a Gram’s stain reveals positive rods. Physicians usually begm treatment immediately, rather than waiting several days for definitive culture-andsensitivity reports. C perfngeens grows freely in an oxygen tension of 30 mm Hg. If oxygen tension is greater than 70 mm Hg, growth is restricted? In treating gas gangrene, HBO therapy i n c r m wound oxygen tension and has a bacteriocidaleffect. It halts exotoxin production and facilitates the action of certain antibiotic agents? Preoperatively, HBO therapy is useful to the surgeon because it helps determine a level of demarcation for the amputation of nonviable tissue.
Necrotizing faCiiti. Necrotizing faciitis and combined synergistic infections also are indications for HBO therapy. The organisms involved in these infections are mixed aerobes and anaerobes. It is important to remember that HBO is an adjunctive therapy. Surgical debridement, antimicrobial therapy, and frequent meticulous wound care are imperative to facilitate healing. Crush injuries. Crush injuries involve severe trauma to blood vessels, soft tissue, and bone. If HBO therapy is initiated acutely, the hyperoxygenation effect may help preserve the viability of the affected limb or tissue. Acute traumatic kchemia. As a result of severe blood vessel injury, acute traumatic ischemia may occur. The peripheral collateral circulation of an area may not be adequate to maintain tissue perfusion. Hyperbaric oxygen therapy stimulates angiogenesis and osteogenesis, and enhances granulation of Hyperoxygenation of the plasma and body tissue is maintained until blood flow can be restored. Hyperbaric oxygen therapy also enhances collagen deposition and reduces edema by vaSOCOI1StTiCfion.ll Radiation necrosis Osteoradionecrosisand soft tissue radionecrosis may develop after radiation therapy for malignancies (Fig 2). Usually, a proliferative endarteritis develops after radiation, resulting in ischemia to the irradiated area. Blood flow to bone and sofi tissue is affected and results in necrosis of the bone and/or surrounding soft tissue. Tumors of the head and neck often respond well to radiation therapy. Patients who have received radiation therapy of the head and neck often suffer from osteoradionecrosiS of the facial bones. Blood flow to the bone and tissue is reduced, and an avascular bone necrosis develops. Hyperbaric oxygen therapy increases the vascularity to ischemic bone and soft tissue, making surgery of irradiated tissue possible. The stimulation of angiogenesis and collagen deposition in irradiated tissue prepares a vascular soft tissue bed for future bone grafting and reconstructive surgery of soft tissue.12 1375
AORN J O U R N A L
JUNE 1988, VOL. 47, NO 6
Fig 2. A 78-year-old man with a history of slow healing sacral decubitus ulcer after radiation therapy for cancer of the prostate developed ulceration as a result of soft tissue radionecrosis. The photos show his wound (above, le#) after three HBO treatments; (above, right) after 22 HBO treatments when the wound size is decreased and edges are beginning to granulate; and cfollowingpage) after 40 preoperative and 10 postoperative treatments when the wound is completely closed.
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JUNE 1988, VOL. 47, NO 6
Refractory ostaomyelih. When osteomyelitis fails to respond to the standard regimen of antiiiotic and surgical management,HBO therapy, when used as adjunctive therapy, can improve the results of treatment. It helps treat hypoxic wounds by increasing the wound oxygen It also improves the phagccytaisactivity of the leukccytes, thereby aiding in resolving infection, and it stimulates ateogenesis, which helps liU dead space with healthy b0ne.l4 Acute blood loss anem& Hyperbaric oxygen therapy may be a lifesaving measure in cases of acute blood loss anemia when blood transfusions are not available or p i l e . 1 5 When placed under pressure, red blood cellsare capable of absorbing large amour~ts of oxygen. Hyperbaric oxygen therapy can be used to sustain life until blood becomes available or until red blood cells are replenished spontaneously.'6 It has been used successfully in treating people who refuse transfusions on rebous grounds. It also may be useful in trauma situationswhen c r ~ m a t c h eblood d is not available.17
Types of Chambers
C
hambers used for HBO therapy are constructed of clear acrylic walls that allow the patient to watch television and see chamber personnel (Fig 3). A speaker and microphone allow two-way communication. A monoplace chamber accommodates one person and does not allow for hands-on treatment by chamber personnel. This type of chamber is approximately 8 ft long and 3 ft wide, and is mounted on wheels. Advantages include low maintenance costs, easy installation, and easy operation. A registered nurse or respiratory therapist usually tends to the patient in a chamber, and in an emergency situation the patient is decompressed before hands-on care is provided. Multiplace chambers can accommodate two or more people. A dual lock system allows physicians or other medical personnel to enter in an emergency situation; however, a nurse, physician,
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Fig 3. A nurse places a patient inside a monoplace chamber. (Photograph courtesy of Sechrirt Indwfries, Inc, Anaheim, Cali3 or trained technician remains inside the chamber during treatment. Risks to the health care worker would be the same as those to the patient, except the worker breathes only compressed air, not 100% oxygen. Workers are screened on the basis of past medical history and usually must pass a physical, depending on the policy of the institution. A multiplacechamber is more desirable for most patients, especially those who are critically ill and require constant monitoring. When in this type of chamber, oxygen is provided to the patient via mask or hood and is inspired intermittently. Most monoplace chambers do not require such a mask because the entire patient environment is pressurized with 100%oxygen.
Patient Selection
P
lastic and reconstructive surgeons, otolaryngologists, orthopedic surgeons, and oral and maxillofacial surgeons most often refer prospective patients for HBO therapy. The hyperbaric team evaluates the patient immediately, and only begins treatment if the patient meets certain criteria. A detailed, accurate medical history is imperative,as is assessment of pulmonary status. A baseline chest x-ray often is required
to rule out severe obstructive pulmonary disease or pneumothorax. Patients with a history of airtrapping disorders, such as asthma, or spontaneous pneumothorax usually are rejected as candidates because HBO therapy could lead to barotrauma. A room-air arterial blood gas usually is required before treatment. Patients with a partial pressure of carbon dioxide (PCO,) greater than 60 tom also may be disqualified, depending on accompanying history. Pulmonary function studies may be necessary on patients with abnormal chest xrays or arterial blood gases. Bronchodilatortherapy and slow ascent rates may be used for patients with mild obstructive pulmonary disease. Any patient with blebs or air-containing cysts is rejected. Workers also may be disqualified for the same reasons a patient would be disqualified. Physicians perform otoscopic examination and instruct the patient to perform a Valsalva maneuver to clear his or her ears. If the patient has had a tracheostomy, is intubated, or is unable to perform a Valsalva, it may be necessary to insert polyethylene tubes or perform a myringotomy. Patients with a history of insulin dependent diabetes mellitus must be closely monitored because HBO therapy alters insulin dependency needs. In the context of HBO therapy, oxygen should
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AORN J O U R N A L
be considered as a therapeutic agent being delivered in doses hgher than those found in room air. Excessive doses of oxygen may be toxic to the patient. The most common manifestation of oxygen toxicity relates to damage to the alveoli of the lungs and seizure activity. Patients with history of epilepsy or other seizure disorders, particularly those who are noncompliant with anticonvulsant therapy, are at an increased risk of developing toxicity. These patients are generally considered high risk and HBO therapy is contraindicated. Although toxicity is not often seen with protocols commonly used for HBO therapy, the health care worker and the patient must be aware of these risks. Claustrophobic patients in monoplace chambers may require sedation. Physicians often prescribe oral diazepam for these patients and constantly reassure them that they are not alone. Claustrophobiausually is not a problem in multiplace chambers.
Patient Preparation
B
efore each treatment, patients must remove any metal jewelry and change into a 100% cotton gown. No matches, cigarettes, or lighters are permitted in the chamber, and suicidal patients should be carefully inspectedfor these items. Sedation, nasal spray, or other medications are administered if indicated. Nasogastric tubes are unclamped and open to air. When treating intubated patients, the nurse, respiratory therapist, or other health care worker deflates tracheal tube cuff balloons and fills them with water. This is done because as the patient is compressed (descended) the volume of air in the balloon will be reduced (Boyle's law). As the patient is decompressed (brought to the surface), the air in the cuff will expand and fill the balloon again. Filling the cuff with water prevents the deflation and reexpansion that occurs during the compression and decompression phases and prevents displacement of the tube. It also allows the patient to receive proper tidal volumes and prevents tracheal damage. The health care worker also makes the patient comfortable, closes the door, and administers the oxygen. A patient with upper respiratory problems or sinusitis may experience severe ear pain and difficulty clearing his or her ears. In such a case, 1382
the treatment is aborted and resumed when the problem has been resolved. The number of treatments varies, depending on the extent of the injury and the individual's healing process, but usually between 20 and 40 are needed. At Jackson Memorial Hospital, all patients undergoing HBO therapy for wound healing are exposed to 2.5 ATA for 90 minutes each treatment.
A
long with the documented benefits, there are risks involved in HBO therapy. Oxygen toxicity may be manifested by the central nervous system as seizures and pulmonary effects, such as dyspnea.**Barotrauma may affect any aircontaining cavity in the body. It can cause pain in the ears, sinuses, or teeth, or be evidenced in a pneumothorax or subcutaneous emphysema.'9 Claustrophobia may be a factor, especially in monoplace chambers. This can be reduced by continuous communication between the health care professional and the patient. Sedation or use of a multiplace chamber may be necessary. Oxygen is a highly flammable gas, especially under pressure, and 6re danger must not be forgotten. Health care workers must take precautions to avoid any potentially h a b l e agent that may result in ignition. Petroleum products, hair sprays or other hair preparations, nail polish, body lotions or creams, or any dressing preparations containing these products should be prohibited in the chamber.
Cost-Eflectivems
H
yperbaric oxygen therapy is expensive. The direct cost may average $7,000 to $10,000. It is, however, cost-effective when compared with other therapeutic modalities and when considering the reduction in hospital stay. Immeasurable hctors of HBO therapy include the patient's return to a normal way of life, to family, and to society. One physician predicts that standard protocols will be established in the future for the proper preparation and training of more physicians, nurses, and technicians to enable a greater number of patients to benefit from HBO therapy. With proper and careful patient screening, HBO
JUNE 1988, VOL. 47, NO 6
therapy is relatively cost-effective. The need for trained technicians, nurses, and physicians to deliver HBO therapy has opened another avenue of specialization for medical professionals. The future of HBO therapy is promising in the field of surgery because it enhances the healing of problematic wounds, decreases length of hospitalization, and 0 improves the quality of patient care. Notes 1 . K Dernocoer, “Hyperbaric oxygen therapy,” Journal of Emevemy Medical Services (August 1984) 28. 2. M C Ross, ‘‘Healing under pressure,” American Journal of Nursing 86 (October 1986) 11 18-1 119. 3. M B Straw, R L Samson, “Decompression sickness: An update,” The Physicim and Sportmedicine 14 (March 1986) 1%. 4. J Davis, ed, Hyperbaric and Undersea Medicine “Theories of inert gas elimination’’ by A R Behnke (San Antonio, Tex: Medical Seminars, Inc, 1981) 2. 5. J Davis, ed,Hypedmk Oxygen Therapy (Bethesda, Md: Undersea Medical Society, 1977) 179. 6. J Davis, ed, Hyperbaric and Undersea Medicine ‘The hyperbaric treatment of carbon monoxide poisoning and smoke inhalation” by E P Kindwall (San Antonio, Tex: Medical S e d , Inc, 1981) 4. 7. Bid, 5. 8. J Davis, ed, Hyperbaric and Undersea Medicine “Gas gangrene part I” by R D Heimbach (San Antonio, Tex: Medical Seminars,Inc, 1981) 3. 9. Ibid, 4; M B Straw et al, Hyperbaric Oxygen Therapy in Emetgewy Medicine (Long Beach, Calif: Memorial Hospital of Long Beach, Baromedical Department, 1985) 5. 10. Straw et al, Hyperbaric Oxygen Therapy in Emergency Medicine, 2; Demccoer, “Hyperbaric oxygen therapy,” 29. 11. Straw et al, Hyperbaric Oygen Therqy in Emergency M&k, 2. 12. R E Marx, radione necrosis of the jaws: Review and update,” Hyperbaric Oxygen Review 5 (April 1984) 116. 13. Davis, Hyperbaric Oxygen Therapy, 217. 14. Bid 15. “The uses of 0, under pressure,” Emergency Medicine 18 (March 1986) 41. 16. Straw, Hyperbaric Oxygen Therapy in Emergemy Medicine, 12. 17. ‘“Theuses of 0, under pressure,” 42. 18. J Davis, ed, Hyperbaric and Undersea Medicine “Oxygen poisoning” by J M Clark (San Antonio, Tex: Medical Seminars, Inc, 1981) 5. 19. Dernocoer, “Hyperbaric oxygen therapy,” 3 1.
AORN JOURNAL
Digitalis Associated with Depression Many postmyocardial infarction (MI) patients experience depression, and it has long been thought of as a natural consequence of the infarction. Recent studies, however, indicate that it is associated with digitalis, according to an article in the Jan 11, 1988, issue of Medical World News. In a study of 172 acute MI patients, patients taking digitalis, beta blockers, and other cardiac drugs were identified. They were evaluated eight to 10 days after the MI and then again after three months. Researchers found a connection between depression and digitalis when the drug was administered in therapeutic doses. The depression was associated with altered mood, appetite loss, reduced sex drive, and inability to sleep. The team found that the correlation was independent of variables such as age, sex, ejection fraction, post-MI ischemia, prior MI, functional impairment, diabetes, and smoking. The team found no link between depression and other frequently prescribed cardiac drugs, including beta blockers. The physician that led the research said digitalis may induce depression by affecting neurotransmitters, such as serotonin, dopamine, and norepinephrine, which are important in the pathophysiology of depression, according to the article. He stressed that the study results need to be confirmed in a larger trial. One physician believes that because digitalis has been used for so long, a strong association would have been noted before now. He said researchers studying the correlation should carefully control the variables. Another physician noted that digitalis is used for patients with lower ejection fractions, more congestive heart failure, and more arrhythmias. These patients may be more depressed, he said.
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Hyperbaric Oxygen Therapy A GUIDE FOR THE PERIOPERATIVE NURSE
Michelle Glowacki, R N Norma Chew, RN
H
yperbaric oxygen (HBO) therapy, which is the administration of 100% oxygen by inhalation within a chamber with greater than atmospheric pressure, was developed to relieve “the bends” experienced by deepsea divers. It has been more than 20 years since the therapy made a mark on the medical field, and its acceptance as an effective mode of treatment for various conditions is apparent by the fact that more medical centers in the United States are providing HBO therapy facilities for those patients it will benefit. At Jackson Memorial Hospital, Miami, HBO therapy is used in the otolaryngology, oral and maxillofacial surgery, orthopedic surgery, plastic and reconstructive surgery, general surgery, and medical departments. More than 1,600 “dives” were administered to a total of more than 100 patients between January 1987 and December 1987. HBO therapy is used spedically for problem wounds and help in the healing process, according to an oral surgeon at that hospital. He emphasizes that the therapy will not accelerate normal healing, but when it is used in conjunction with debridement and/or reconstructive surgery, it enhances healing (Fig 1). Another physician claims that one of the keys to success in HBO therapy is the physician’sjudgment in selecting patients who will benefit from treatment. The bends and problematic wounds will remain the two major uses of HBO therapy, but with more research and experimental studies, it could be used in other areas such as sports medicine, and spinal cord and head injuries, he said. In the future, HBO therapy will be a more defined, quantitative, sophisticated mode of treatment. 1370
This article addresses the indications, patient selection and preparation,risks, and mt-effectiveness of HBO therapy. The basic principles of HBO therapy can be explained with three laws of physics. Henry’s law: At a given temperature, the amount of gas that will dissolve in a liquid is directly proportional to the pressure of the gas. Under such great pressure, then, HBO therapy saturates plasma with oxygen. Dalton’s law: The total pressure of a mixture of gases is the sum of the partd pressure of each of the gases. Oxygen administered at 3 atmospheres absolute (ATA) would, therefore, produce a partial pressure of oxygen (PO3 of approximately 2,000 mm Hg.’ Michelle Glowacki, RN,BSN, CCRN, is an RN II in the department of anesthesia, division of hyperbaric and aquatic medicine, Jackson Memorial Hospital, Miami. She earned her associate of arts degree in general studies from the University of South Florida, Tampa, and her bachelor of science degree in nursingfrom Florida State University, Tallahassee. Norma Chew,RN,is a specialty coordinatorfor ear, nose, and throat and plastic surgety, Jackson Memorial Hospital, Miami She has a diploma in nursing from Kingston Public Hospital School of Nursing, Kingston, Jamaica, West Indies.
The authors acknowledge Jeffrey Hartog, MD, for his support and input.
JUNE 1988, VOL. 47. NO 6
AORN JOURNAL
Fig 1. A 68-year-old woman with a history of insulin dependent diabetes mellitus had a cut on her hand that healed very slowly. The photo (above) shows her hand after surgical debridement and three HBO treatments and (right) after 20 HBO treatments when the wound is completely healed.
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Hyperbaric oxygen therapy is used with antibiotics and surgery to enhance healing. Boyle’s law: At a constant temperature, the volume of a gas is inversely proportional to its pressure. The use of HBO, therefore, will result in a reduction of bubble size, as in the case of decompression sickness or arterial gas embolism.
Indications
H
yperbaric oxygen therapy has been used for many years and is indicated for various conditions. It is used in conjunction with antibiotic therapy and surgery to enhance the healing process of patients with radiation necrosis of the bone and soft tissue, gas gangrene, and skin ulcers of diabetes? Decompression sickness. Hyperbaric oxygen therapy is used for treating decompression sickness (DCS). In modern times, DCS is associated almost exclusively with underwater diving. Historically, DCS was known as the “bends” or caisson disease and was first described in workers building bridges in underwater airtight containers called caissons. Workers would experience joint pain after surfacing that developed into a flexed and contorted posture-the bends? Decompression sickness is caused by the formation of bubbles in the tissue during the ascent phase of a dive, after inspiration of inert gases under pressure. A rapid or emergency ascent, or failure to comply with standard decompression tables, may result in DCS in divers. The HBO treatment reduces bubble size and accelerates counterddbion, forcing oxygen into the cells and inert gases (often nitrogen) out4 Immediately after ascending from a deep sea dive, a patient may be unconscious. He or she also may experience joint pain, paresthesias, dyspnea, or even paralysis several hours after a dive. If the patient is unresponsive, emergency treatment must be initiated. Establishing a patent airway and kgumng cardiopulmonary resuscitation is vital before transporting the patient to a hyperbaric facility for 1374
compression. The patient should be placed in a leftsidedown reverse Trendelenburg position if possible. If the patient must be transported via aircraft, a cabin pressurized to sea level will prevent exacerbation of DCS symptoms. Once the patient is safely transported to the hyperbaric facility, he or she is placed inside the chamber and the “dive” (compression) is initiated. Depending on the patient’s condition, he or she is gradually decompressed according to standard diving decompression tables. Carbon momx& intoxication. Hyperbaric oxygen therapy also is indicated in treating carbon monoxide (CO) intoxication, which occurs after prolonged exposure to CO. Carbon monoxide is a colorless, odorless gas which is a product of incomplete combustion of hydrocarbon compounds. It is toxic and cam asphyxiation and hypoxia. Expure to CO commonly is c a d by fumes 60m a fire or exhaust fumes from an internal combustion engine. Early clinical signs and symptoms include headache and vertigo, and because these symptom are attributed to a multitude of other disorders, it is important to determine exposure to CO. The CO molecule has an affinity 200 times greater than that of oxygen to attach to the hemoglobin molecule? It binds with hemoglobin, forming carbxyhemoglobin (COHb). This leaves less 6ee hemoglobin available for oxygen transport to body tissues. The CO molecule also has been found to combine with the cytochrome a3 oxidax in the mitochondria of the cell, blocking cellular metabkm.6 Hyperbaric oxygen therapy is indicated for treating carbon monoxide intoxication because it speeds the release of CO from the hemoglobin and maintains sufficientoxygenation of body tissue and vital organs by hyperoxygenating the plasma. If untreated, after apparent complete recovery from CO intoxication, the exposed individual may exhibit some neurological dysfunction such as dementia or extrapyramidal symptoms
AORN JOURNAL
JUNE 1988, VOL. 47, NO 6
It is important to remember that hyperbaric oxygen therapy is an adjunctive therapy.
several days after exposure.’ It is important, therefore, to treat any person who shows signs of any type of cerebral dysfunction (eg, headache, loss of consciousness) regardless of COHb level. Arterial gas embolism. Hyperbaric oxygen therapy can be used to treat arterial gas embolism by reducing the bubble size (Boyle’s law). This embolism can result from barotrauma, a pulmonary overpressure accident caused by the patient holding his or her breath on the ascent phase of a dive, or if pulmonary gas trapping ( as in bronchospasm due to asthma) occurs at depth. A pulmonary overpressure accident can result in a tension pneumothorax, pneumomediastinum, and/or subcutaneous emphysema. In the event of a tension pneumothorax, immediate medical intervention and insertion of a chest tube is necessary. Arterial gas embolism also may be iatrogenic. For example, it may occur after air has been introduced into the coronary circulation during cardiac surgery. It also can result from the introduction of air into the extracorporeal circulation during arteriography studies or hemodialysis. Gas gangrene. When tissue is infected with Clostridim pefingem, which is found in soil and in the gastrointestinal tract, gas gangrene may occur. Cpe@ngem produces an alpha exotoxin that causes tissue necrosis. The diagnosis usually is made after a Gram’s stain reveals positive rods. Physicians usually begm treatment immediately, rather than waiting several days for definitive culture-andsensitivity reports. C perfngeens grows freely in an oxygen tension of 30 mm Hg. If oxygen tension is greater than 70 mm Hg, growth is restricted? In treating gas gangrene, HBO therapy i n c r m wound oxygen tension and has a bacteriocidaleffect. It halts exotoxin production and facilitates the action of certain antibiotic agents? Preoperatively, HBO therapy is useful to the surgeon because it helps determine a level of demarcation for the amputation of nonviable tissue.
Necrotizing faCiiti. Necrotizing faciitis and combined synergistic infections also are indications for HBO therapy. The organisms involved in these infections are mixed aerobes and anaerobes. It is important to remember that HBO is an adjunctive therapy. Surgical debridement, antimicrobial therapy, and frequent meticulous wound care are imperative to facilitate healing. Crush injuries. Crush injuries involve severe trauma to blood vessels, soft tissue, and bone. If HBO therapy is initiated acutely, the hyperoxygenation effect may help preserve the viability of the affected limb or tissue. Acute traumatic kchemia. As a result of severe blood vessel injury, acute traumatic ischemia may occur. The peripheral collateral circulation of an area may not be adequate to maintain tissue perfusion. Hyperbaric oxygen therapy stimulates angiogenesis and osteogenesis, and enhances granulation of Hyperoxygenation of the plasma and body tissue is maintained until blood flow can be restored. Hyperbaric oxygen therapy also enhances collagen deposition and reduces edema by vaSOCOI1StTiCfion.ll Radiation necrosis Osteoradionecrosisand soft tissue radionecrosis may develop after radiation therapy for malignancies (Fig 2). Usually, a proliferative endarteritis develops after radiation, resulting in ischemia to the irradiated area. Blood flow to bone and sofi tissue is affected and results in necrosis of the bone and/or surrounding soft tissue. Tumors of the head and neck often respond well to radiation therapy. Patients who have received radiation therapy of the head and neck often suffer from osteoradionecrosiS of the facial bones. Blood flow to the bone and tissue is reduced, and an avascular bone necrosis develops. Hyperbaric oxygen therapy increases the vascularity to ischemic bone and soft tissue, making surgery of irradiated tissue possible. The stimulation of angiogenesis and collagen deposition in irradiated tissue prepares a vascular soft tissue bed for future bone grafting and reconstructive surgery of soft tissue.12 1375
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Fig 2. A 78-year-old man with a history of slow healing sacral decubitus ulcer after radiation therapy for cancer of the prostate developed ulceration as a result of soft tissue radionecrosis. The photos show his wound (above, le#) after three HBO treatments; (above, right) after 22 HBO treatments when the wound size is decreased and edges are beginning to granulate; and cfollowingpage) after 40 preoperative and 10 postoperative treatments when the wound is completely closed.
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Refractory ostaomyelih. When osteomyelitis fails to respond to the standard regimen of antiiiotic and surgical management,HBO therapy, when used as adjunctive therapy, can improve the results of treatment. It helps treat hypoxic wounds by increasing the wound oxygen It also improves the phagccytaisactivity of the leukccytes, thereby aiding in resolving infection, and it stimulates ateogenesis, which helps liU dead space with healthy b0ne.l4 Acute blood loss anem& Hyperbaric oxygen therapy may be a lifesaving measure in cases of acute blood loss anemia when blood transfusions are not available or p i l e . 1 5 When placed under pressure, red blood cellsare capable of absorbing large amour~ts of oxygen. Hyperbaric oxygen therapy can be used to sustain life until blood becomes available or until red blood cells are replenished spontaneously.'6 It has been used successfully in treating people who refuse transfusions on rebous grounds. It also may be useful in trauma situationswhen c r ~ m a t c h eblood d is not available.17
Types of Chambers
C
hambers used for HBO therapy are constructed of clear acrylic walls that allow the patient to watch television and see chamber personnel (Fig 3). A speaker and microphone allow two-way communication. A monoplace chamber accommodates one person and does not allow for hands-on treatment by chamber personnel. This type of chamber is approximately 8 ft long and 3 ft wide, and is mounted on wheels. Advantages include low maintenance costs, easy installation, and easy operation. A registered nurse or respiratory therapist usually tends to the patient in a chamber, and in an emergency situation the patient is decompressed before hands-on care is provided. Multiplace chambers can accommodate two or more people. A dual lock system allows physicians or other medical personnel to enter in an emergency situation; however, a nurse, physician,
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Fig 3. A nurse places a patient inside a monoplace chamber. (Photograph courtesy of Sechrirt Indwfries, Inc, Anaheim, Cali3 or trained technician remains inside the chamber during treatment. Risks to the health care worker would be the same as those to the patient, except the worker breathes only compressed air, not 100% oxygen. Workers are screened on the basis of past medical history and usually must pass a physical, depending on the policy of the institution. A multiplacechamber is more desirable for most patients, especially those who are critically ill and require constant monitoring. When in this type of chamber, oxygen is provided to the patient via mask or hood and is inspired intermittently. Most monoplace chambers do not require such a mask because the entire patient environment is pressurized with 100%oxygen.
Patient Selection
P
lastic and reconstructive surgeons, otolaryngologists, orthopedic surgeons, and oral and maxillofacial surgeons most often refer prospective patients for HBO therapy. The hyperbaric team evaluates the patient immediately, and only begins treatment if the patient meets certain criteria. A detailed, accurate medical history is imperative,as is assessment of pulmonary status. A baseline chest x-ray often is required
to rule out severe obstructive pulmonary disease or pneumothorax. Patients with a history of airtrapping disorders, such as asthma, or spontaneous pneumothorax usually are rejected as candidates because HBO therapy could lead to barotrauma. A room-air arterial blood gas usually is required before treatment. Patients with a partial pressure of carbon dioxide (PCO,) greater than 60 tom also may be disqualified, depending on accompanying history. Pulmonary function studies may be necessary on patients with abnormal chest xrays or arterial blood gases. Bronchodilatortherapy and slow ascent rates may be used for patients with mild obstructive pulmonary disease. Any patient with blebs or air-containing cysts is rejected. Workers also may be disqualified for the same reasons a patient would be disqualified. Physicians perform otoscopic examination and instruct the patient to perform a Valsalva maneuver to clear his or her ears. If the patient has had a tracheostomy, is intubated, or is unable to perform a Valsalva, it may be necessary to insert polyethylene tubes or perform a myringotomy. Patients with a history of insulin dependent diabetes mellitus must be closely monitored because HBO therapy alters insulin dependency needs. In the context of HBO therapy, oxygen should
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be considered as a therapeutic agent being delivered in doses hgher than those found in room air. Excessive doses of oxygen may be toxic to the patient. The most common manifestation of oxygen toxicity relates to damage to the alveoli of the lungs and seizure activity. Patients with history of epilepsy or other seizure disorders, particularly those who are noncompliant with anticonvulsant therapy, are at an increased risk of developing toxicity. These patients are generally considered high risk and HBO therapy is contraindicated. Although toxicity is not often seen with protocols commonly used for HBO therapy, the health care worker and the patient must be aware of these risks. Claustrophobic patients in monoplace chambers may require sedation. Physicians often prescribe oral diazepam for these patients and constantly reassure them that they are not alone. Claustrophobiausually is not a problem in multiplace chambers.
Patient Preparation
B
efore each treatment, patients must remove any metal jewelry and change into a 100% cotton gown. No matches, cigarettes, or lighters are permitted in the chamber, and suicidal patients should be carefully inspectedfor these items. Sedation, nasal spray, or other medications are administered if indicated. Nasogastric tubes are unclamped and open to air. When treating intubated patients, the nurse, respiratory therapist, or other health care worker deflates tracheal tube cuff balloons and fills them with water. This is done because as the patient is compressed (descended) the volume of air in the balloon will be reduced (Boyle's law). As the patient is decompressed (brought to the surface), the air in the cuff will expand and fill the balloon again. Filling the cuff with water prevents the deflation and reexpansion that occurs during the compression and decompression phases and prevents displacement of the tube. It also allows the patient to receive proper tidal volumes and prevents tracheal damage. The health care worker also makes the patient comfortable, closes the door, and administers the oxygen. A patient with upper respiratory problems or sinusitis may experience severe ear pain and difficulty clearing his or her ears. In such a case, 1382
the treatment is aborted and resumed when the problem has been resolved. The number of treatments varies, depending on the extent of the injury and the individual's healing process, but usually between 20 and 40 are needed. At Jackson Memorial Hospital, all patients undergoing HBO therapy for wound healing are exposed to 2.5 ATA for 90 minutes each treatment.
A
long with the documented benefits, there are risks involved in HBO therapy. Oxygen toxicity may be manifested by the central nervous system as seizures and pulmonary effects, such as dyspnea.**Barotrauma may affect any aircontaining cavity in the body. It can cause pain in the ears, sinuses, or teeth, or be evidenced in a pneumothorax or subcutaneous emphysema.'9 Claustrophobia may be a factor, especially in monoplace chambers. This can be reduced by continuous communication between the health care professional and the patient. Sedation or use of a multiplace chamber may be necessary. Oxygen is a highly flammable gas, especially under pressure, and 6re danger must not be forgotten. Health care workers must take precautions to avoid any potentially h a b l e agent that may result in ignition. Petroleum products, hair sprays or other hair preparations, nail polish, body lotions or creams, or any dressing preparations containing these products should be prohibited in the chamber.
Cost-Eflectivems
H
yperbaric oxygen therapy is expensive. The direct cost may average $7,000 to $10,000. It is, however, cost-effective when compared with other therapeutic modalities and when considering the reduction in hospital stay. Immeasurable hctors of HBO therapy include the patient's return to a normal way of life, to family, and to society. One physician predicts that standard protocols will be established in the future for the proper preparation and training of more physicians, nurses, and technicians to enable a greater number of patients to benefit from HBO therapy. With proper and careful patient screening, HBO
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therapy is relatively cost-effective. The need for trained technicians, nurses, and physicians to deliver HBO therapy has opened another avenue of specialization for medical professionals. The future of HBO therapy is promising in the field of surgery because it enhances the healing of problematic wounds, decreases length of hospitalization, and 0 improves the quality of patient care. Notes 1 . K Dernocoer, “Hyperbaric oxygen therapy,” Journal of Emevemy Medical Services (August 1984) 28. 2. M C Ross, ‘‘Healing under pressure,” American Journal of Nursing 86 (October 1986) 11 18-1 119. 3. M B Straw, R L Samson, “Decompression sickness: An update,” The Physicim and Sportmedicine 14 (March 1986) 1%. 4. J Davis, ed, Hyperbaric and Undersea Medicine “Theories of inert gas elimination’’ by A R Behnke (San Antonio, Tex: Medical Seminars, Inc, 1981) 2. 5. J Davis, ed,Hypedmk Oxygen Therapy (Bethesda, Md: Undersea Medical Society, 1977) 179. 6. J Davis, ed, Hyperbaric and Undersea Medicine ‘The hyperbaric treatment of carbon monoxide poisoning and smoke inhalation” by E P Kindwall (San Antonio, Tex: Medical S e d , Inc, 1981) 4. 7. Bid, 5. 8. J Davis, ed, Hyperbaric and Undersea Medicine “Gas gangrene part I” by R D Heimbach (San Antonio, Tex: Medical Seminars,Inc, 1981) 3. 9. Ibid, 4; M B Straw et al, Hyperbaric Oxygen Therapy in Emetgewy Medicine (Long Beach, Calif: Memorial Hospital of Long Beach, Baromedical Department, 1985) 5. 10. Straw et al, Hyperbaric Oxygen Therapy in Emergency Medicine, 2; Demccoer, “Hyperbaric oxygen therapy,” 29. 11. Straw et al, Hyperbaric Oygen Therqy in Emergency M&k, 2. 12. R E Marx, radione necrosis of the jaws: Review and update,” Hyperbaric Oxygen Review 5 (April 1984) 116. 13. Davis, Hyperbaric Oxygen Therapy, 217. 14. Bid 15. “The uses of 0, under pressure,” Emergency Medicine 18 (March 1986) 41. 16. Straw, Hyperbaric Oxygen Therapy in Emergemy Medicine, 12. 17. ‘“Theuses of 0, under pressure,” 42. 18. J Davis, ed, Hyperbaric and Undersea Medicine “Oxygen poisoning” by J M Clark (San Antonio, Tex: Medical Seminars, Inc, 1981) 5. 19. Dernocoer, “Hyperbaric oxygen therapy,” 3 1.
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Digitalis Associated with Depression Many postmyocardial infarction (MI) patients experience depression, and it has long been thought of as a natural consequence of the infarction. Recent studies, however, indicate that it is associated with digitalis, according to an article in the Jan 11, 1988, issue of Medical World News. In a study of 172 acute MI patients, patients taking digitalis, beta blockers, and other cardiac drugs were identified. They were evaluated eight to 10 days after the MI and then again after three months. Researchers found a connection between depression and digitalis when the drug was administered in therapeutic doses. The depression was associated with altered mood, appetite loss, reduced sex drive, and inability to sleep. The team found that the correlation was independent of variables such as age, sex, ejection fraction, post-MI ischemia, prior MI, functional impairment, diabetes, and smoking. The team found no link between depression and other frequently prescribed cardiac drugs, including beta blockers. The physician that led the research said digitalis may induce depression by affecting neurotransmitters, such as serotonin, dopamine, and norepinephrine, which are important in the pathophysiology of depression, according to the article. He stressed that the study results need to be confirmed in a larger trial. One physician believes that because digitalis has been used for so long, a strong association would have been noted before now. He said researchers studying the correlation should carefully control the variables. Another physician noted that digitalis is used for patients with lower ejection fractions, more congestive heart failure, and more arrhythmias. These patients may be more depressed, he said.
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