Hyperbaric Medicine(HyperBaric Oxygen Therapy)

Michal Palkovič

Overview

• What is HBOT

• History and Present

• What equipment is used

• Physics and Physiological principles

• Therapeutical principles

• Indications, Complications

What is HBOT

• HBOT is the use of oxygen at a level

higher than atmospheric pressure for

medical purposes

• Equipment: Pressure chamber, oxygen

What is HBOT

• Delivery thru oxygen breathing

• alveolar oxygen pressure is at 100 mmHg = hemoglobin is about 97% saturated

• alveolar oxygen pressure if oxygen applied = hemoglobin is about 100% saturated

• After hemoglobin is fully saturated, additional oxygen is carried to the tissues in physical solution in plasma. HBO does not significantly increase hemoglobin’s transport of oxygen, but elevates the capillary plasma oxygen transport.

• HBOT is based on two physical factors related to the hyperbaric environment:– mechanical effects of pressure

– increased oxygenation of tissues

History

• 1662, a British clergyman, Henshaw,

“domicilium” driven by organ bellows, with

valves to control the flow of air

• 1773 - Carl Wilhelm Scheele and 1777 Antoine

Lavoisier – oxygen

• 1830 - 2 and 4 ATA improve the cerebral blood

flow, and produce a feeling of well being

• 1837 - Pravaz built a large hyperbaric

chamber used for pulmonary diseases - TBC,

laryngitis, tracheitis, pertussis, deafness,

cholera, rickets, menorrhagia and conjunctivitis

History

• 1845 - Triger wrote about symptoms in coal miners consistent with decompression sickness

• 1876 - Bert reported that nitrogen bubbles formed in tissue during rapid decompression

• Williams, in the British Medical Journal of 1885, made a comment: "The use of atmospheric air under different degrees of atmospheric pressure, in the treatment of disease, is one of the most important advances in modern medicine and when we consider the simplicity of the agent, the exact methods by which it may be applied, and the precision with which it can be regulated to the requirements of each individual, we are astonished that in England this method of treatment has been so little used".

History

• 1907 - John Scott Haldane (1860 -1936), a Scottish physiologist, made a decompression apparatus to help make deep-sea divers safer and produced the first decompression tables after extensive experiments with animals.

• 1912 - United States Navy Diving Manual, US Navy Air Decompression Tables

• 1920 - Cunningham - treat the victims of the Spanish influenza epidemic

Present

• Researchers conducting wound-healing

studies continued to try to take advantage

of the angiogenic properties of increasing

oxygen gradients resulting from hyperbaric

therapy. Foot wounds from diabetes,

radiation ulcers, and other ischemic

wounds have been successfully treated

with Hyperbaric Medicine.

What equipment is used

• When a patient is given 100% oxygen under pressure, hemoglobin is saturated, but the blood can be hyperoxygenated by dissolving oxygen within the plasma. The patient can be administered systemic oxygen via chambers: – Type A, multiplace

– Type B, monoplace

Topox, is administered through a small chamber that is placed over an extremity and pressurized with oxygen

Portable "mild" hyperbaric chamber. These soft vessels can be pressurized to 1.5-1.7 ATA, only approved for treatment of altitude illness.

Decompression sicknes

Physics• Pressure of gases is defined as a force

per unit area

• At surface pressure = 760 mm mercury = 1 atmosphere

• Every -10m msw +1 atm is added (2 ata in 10msw, 3 ata in 20msw)

• Boyle’s Law – Pressure-volume relationship. volume of gas is inversely proportional to the pressure (P1/P2 = V2/V1)

Decompression sicknes

Physics

• Dalton’s Law: Total pressure exerted by a

mixture of gases is equal to the sum of the

pressure of each of the different gases

• Henry’s Law: Gas in Solution. The

amount of gas dissolved in a liquid is

directly proportional to the partial pressure

of the dissolved gas (P1/P2=A1/A2)

Physiological principles

• Mechanical Effects:

– Boyle’s law == Volume is changed in a

geometric progression related to pressure

change; large reductions take place near the

surface, with subsequent reductions

becoming smaller at higher pressure. These

mechanical effects are responsible for

unwanted barotraumas that may result in

middle-ear squeeze, sinus squeeze, and burst

of lung if the patient holds their breath during

decompression.

Physiological principles

• Oxygen Solubility:

– Dalton’s Law == air at sea level pressure (760mm Hg) contains 21% oxygen with a PO2 of 160 mmHg. When the chamber is pressurized with air to 3 ATA PO2 is 479 mmHg which is equivalent of breathing 63% oxygen at sea level.

– Henry’s Law == Oxygen is transported by the blood from the lungs into the tissue by two methods:

• Hemoglobin

• Hyperoxygenated plasma

Therapeutical principles

• Reverse Hypoxia / Alter ischemic effect

• Reduce edema

– Hyperoxygenation will cause vasoconstriction

• Modulate nitric oxide production

– nitric oxide=vasodilation, nitric

oxide=vasoconstriction.

• Modify growth factors and cytokine effect

– HBOT induces production of VEGF thereby

stimulating more rapid development of capillary

budding and granulation formation within the wound

bed

Therapeutical principles

• Promote cellular proliferation

• Accelerate collagen deposition

• Accelerate microbial oxidative killing

• Improve select antibiotic exchange acrossmembranes– HBO may potentiate the activity of certain

antimicrobials by inhibiting biosynthetic reactions in bacteria

• Interfere with bacterial disease propagation by denaturing toxins

• Modulate the immune system response

• HBOT increases the amount and activity of the free radical scavenger superoxide dismutase

Indications

• Air or gas Embolism

• Carbon Monoxide poisoning

• Clostridial myositis and myonecrosis

• Crush injury, compartment syndrome, and other acute ischemias

• Decompression sickness

• Enhancement of healing in selected wounds

• Exceptional anemia

• Intracranial abscess

• Necrotizing soft tissue infections

• Refractory Osteomyelitis

• Delayed radiation injury (soft tissue and bony necrosis)

• Skin grafts and flaps

• Thermal burns

Indications

• Fungal disease (Fungal Pneumonia)

• Thermal burns, carbon monoxide, smoke

inhalation

• Closed head injuries

• Ileus

• CNS edema/perinatal asphyxia

• Peripheral neuropathies

• Exertional rhabdomyolysis

• Cellulitis, compartment syndrome

• Ischemic injuries (Laminitis)

Pathology

• Fungal disease (Fungal Pneumonia)

• Thermal burns, carbon monoxide, smoke

inhalation

• Closed head injuries

• Ileus

• CNS edema/perinatal asphyxia

• Peripheral neuropathies

• Exertional rhabdomyolysis

• Cellulitis, compartment syndrome

• Ischemic injuries (Laminitis)

Vnútorná obhliadka hrudnej a brušnej dutiny 30 minút po reálnom ponore (a.) a 30 minút po „explozívnej“ dekompresii (b.).

a. b.

Pohľad na ústny otvor 30 minút po reálnom ponore (a.) a 30 minút po explozívnej dekompresii (b.).

a. b.

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