•Mountain Medicine•Under-Water Medicine•Medicine on Exposure to Extremes of Temperature

•Space and Aviation Medicine

MEDICINE AND PHYSIOLOGY MEDICINE AND PHYSIOLOGY IN UNUSUAL ENVIRONMENTIN UNUSUAL ENVIRONMENT

•DEEP-SEA DIVING PHYSIOLOGY

•SUB AQUATIC MEDICINE

•UNDER-WATER MEDICINE

CASECASEA sailer dived in the sea upto about 100 feet depth. When he came back to the surface of sea, he was exhausted, complained of severe pain and swelling of joints [esp knee and ankle joints] and hardly could move those. Some skin rashes were visible with severe itch. He was a bit drowsy and disoriented.

OBJECTIVEOBJECTIVE“To have safe diving“

To Learn:-• Orientation Under-Water• Pathophysiology of Under-Water

Medicine• Medical Problems [Disorders] of Deep-

Sea Diving• Decompression Sickness• Uses of Hyperbaric Oxygen Therapy

USES OF DEEP SEA DIVINGUSES OF DEEP SEA DIVING

•RECREATIONAL

•OIL & SALVAGE

•COMBAT

ORIENTATION UNDER ORIENTATION UNDER WATERWATER

• VISION

• HEARING

• EQUILIBRIUM

• RULES FOR DIVING

EFFECT OF SEA DEPTH ON EFFECT OF SEA DEPTH ON PRESSURE AND ON GAS PRESSURE AND ON GAS

VOLUMESVOLUMESDepth (feet)Atmosphere (s)

Sea level 1 33 2 66 3100 4133 5166 6200 7300 10400 13500 16

FACTORS AFFECTING IN FACTORS AFFECTING IN DIVINGDIVING

• Total Pressure [Depth]• Duration of Dive• Activity of Diver• Temp of Water• Drugs within body• Gas Mixtures• Rate of Descent/

Ascent

EFFECTS OF DIVINGEFFECTS OF DIVINGHEMATOLOGICAL• Hct• Platelets• DLC• TLC• Diuresis• Weight Loss• Rise in NH4

RESPIRATIONRESPIRATION

• CO2 Retention

• Dyspnoea

• Ventilation

CVSCVS• Arrhythmias

• Hypertrophy

• Cardiac Contractility

• R.V. Overload

RENALRENAL

• Diuresis

• Resp Acidosis

NEURALNEURAL

•Disturbed mental and motor functions

•Loss of Long-term memory

HORMONALHORMONAL

• Nor-epinephrine

• Epinephrine

• Dopamine

PATHOPHYSIOLOGY OF PATHOPHYSIOLOGY OF UNDER-WATER MEDICINEUNDER-WATER MEDICINE

• BAROMETRIC PRESSURE

• VOLUME OF GASES

• INTRA-THORACIC PRESSURE

• INTRA-ALVEOLAR PRESSURE

PATHOPHYSIOLOGYPATHOPHYSIOLOGYPARAMETER DEEP

SEA DIVING

HIGH ALTITUDE

• Barometric Pressure

• Volume of Gases

• Intra-thoracic Pressure

• Intra-alveolar Pressure

[Compression]

[Expansion]

MEDICAL PROBLEMS OF MEDICAL PROBLEMS OF DEEP-SEA DIVINGDEEP-SEA DIVING

• Oxygen Toxicity– Lung damage– Convulsions

• HPNS– Tremors– Somnolence

Problems on Descent

• CO2 Toxicity – Initial excitation and later depression of

respiration– Respiratory acidosis– Lethargy– Narcosis

MEDICAL PROBLEMS OF MEDICAL PROBLEMS OF DEEP-SEA DIVINGDEEP-SEA DIVING

• Nitrogen Narcosis– Euphoria– Impaired

performance– Anesthetic effects

• Ear & Sinus Barotraumas

Problems on Descent

MEDICAL PROBLEMS OF MEDICAL PROBLEMS OF DEEP-SEA DIVINGDEEP-SEA DIVING

• Decompression Sickness

• Air Embolism

Problems on Ascent

DECOMPRESSION SICKNESSOR

BENDSOR

HYPER-BARISMOR

DIVER’S PARALYSIS

HISTORYHISTORY

1670 : Boyles described “Decompression”

1830 : Cochrane used compressed air in tunnels and Caissons

1937 : Behnk – discovered “N2 Narcosis”

DECOMPRESSION SICKNESSDECOMPRESSION SICKNESS

• Pathophysiology• Resp Gases at 1 ATA• Gaseous Pressures Outside /

Inside Alveoli of Lungs• Decompression Sickness

Sequence• Decompression Sickness Grading

•Few Pictorial signs of DCS

•Factors Influencing DCS

•Treatment of DCS

•Uses of Hyperbaric Therapy

•Prevention of DCS

PARTIAL PRESSURES OF PARTIAL PRESSURES OF RESPIRATORY GASES AT 1 RESPIRATORY GASES AT 1

ATAATASample Gas Partial Pressure

O2[mm Hg]

CO2[mm Hg]

N2[mm Hg]

H2O[mm Hg]

Total[mm Hg]

Inspired air 158 0.3 596 5.7 760

Expired air 116 32 565 47 760Alveolar

air 100 40 573 47 760

Arterial blood 100 40 573 47 760

Venous blood 40 46 573 47 706

Tissues < 30 > 50 573 47 700

STP = 760 mmHg

Maximum Human Tolerance = 4 – 6 ATA for 4 hours

PRESSURE OUTSIDE BODYPRESSURE OUTSIDE BODY

Gaseous pressure both inside and outside the body, showing at left saturation of the body to high gas pressures when breathing air at a

total pressure of 5000 mm Hg, and at right the great excess of intrabody pressure that is responsible for bubble formation in the

tissues when the body is returned to the normal pressure of 760 mm Hg.

DECOMPRESSION SICKNESS DECOMPRESSION SICKNESS SEQUENCESEQUENCE

DECOMPRESSION SICKNESS DECOMPRESSION SICKNESS GRADINGGRADING

Type I [Pain only]

•Limb or joint pain-dysfunction

•Itch•Skin rash•Localized swelling

Type II [Serious]•Central nervous system disorder

•Inner ear damage•Lungs failure•Cardiac failure

FACTORS INFLUENCING DCSFACTORS INFLUENCING DCS• Exertion• Physical fitness• Temperature –

cold water, hot shower

• Sex – females• Age• Obesity• Dehydration • Increased carbon

dioxide pressures

• Alcohol intake• Physical injury• Adaptation• Dive profile• Rapid and

multiple ascents• Repetitive and

multi-day diving• Altitude

exposure

Skin lesions of decompression sickness. This diver, who had had an upper

limb amputation, developed

‘bends’ pain in the phantom

limb, and skin bends over the

body. Both responded rapidly to recompression

therapy. (Photograph by courtesy of Dr

Ramsey Pearson)

Decompression sickness: skin lesions of isobaric counterdiffusion. The subject breathed a neon/oxygen mixture

at 1200 feet (360 metres), while exposed to a chamber of helium/oxygen. Gross itching accompanied the intradermal

bubbles. (Photograph by courtesy of Professor C. J. Lambertsen)

Curved and concentric lacerations of shark bite – often with teeth left in the wound. (Photograph courtesy of Dr. G. D. Campbell)

TREATMENT OF DECOMPRESSION SICKNESS

INVOLVES IMMEDIATE RECOMPRESSION,

FOLLOWED BY GRADUAL DECOMPRESSION

LOCALIZED PAIN IN OR AROUND A JOINT MAY

SOMETIMES BE RELIEVED BY APPLICATION OF LOCAL

PRESSURE, e.g FROM AN INFLATED

SPHYGMOMANOMETER CUFF

•The value of 100% oxygen, before during and after recompression– Intravascular bubbles do not

develop with oxygen breathing, [especially at 2 ATA]

– Denitrogenation is maximized, reducing tissue bubbles

– It reverses the development and the redevelopment of DCS

PREVENTIONPREVENTION

•GRADED ASCENT

•USE OF SCUBA

•USE OF HELIUM

TREATMENTTREATMENT

•HYPERBARIC OXYGEN THERAPY [RECOMPRESSION THERAPY]

•SUPPORTIVE THERAPY

USES OF HYPERBARIC USES OF HYPERBARIC [RECOMPRESSION] [RECOMPRESSION]

THERAPYTHERAPY•Gas Gangrene•Decompression Sickness•Arterial Gas Embolism•Severe Burns•Myocardial Infarction•Osteomyelitis •Carbon Monoxide Poisoning