ByByDr. M. Anthony David MD,Dr. M. Anthony David MD,

Professor of PhysiologyProfessor of Physiology

RESPIRATION IN UNUSUAL RESPIRATION IN UNUSUAL ENVIRONMENTS: IIENVIRONMENTS: IIDEEP SEA DIVINGDEEP SEA DIVING

EFFECT OF DEPTH ON PRESSURESEFFECT OF DEPTH ON PRESSURES

DEPTH (feet)

PRESSURE (Atms)

MSL (0) 133 266 3

100 4133 5166 6200 7300 10400 13500 16

MSL: Vol: 1 lt Pressure: 1Atm.

33 Ft: Vol: 1/2 ltPressure: 2 Atms.

100 Ft: Vol: 1/4th lt.Pressure : 4 Atms

233 Ft: Vol: 1/8th lt. Pressure : 8 Atms

Why is the volume decreasing?Why is the volume decreasing? As per the Boyle’s Law,As per the Boyle’s Law,

• The The volumevolume is inversely proportional to is inversely proportional to the the pressurepressure of any given gas. of any given gas.

So as the pressure So as the pressure increasesincreases, the , the volume volume decreasesdecreases..

This means that the partial pressures This means that the partial pressures of gases in air also increase along of gases in air also increase along with pressure as one goes down into with pressure as one goes down into the depths!the depths!

1. OXYGEN TOXICITY1. OXYGEN TOXICITY

2. NITROGEN NARCOSIS2. NITROGEN NARCOSIS

3. HIGH PRESSURE NERVOUS 3. HIGH PRESSURE NERVOUS SYNDROME (HPNS)SYNDROME (HPNS)

4. AIR EMBOLISM4. AIR EMBOLISM

PROBLEMS WITH INCREASE OF PROBLEMS WITH INCREASE OF PRESSUREPRESSURE

1. OXYGEN TOXICITY1. OXYGEN TOXICITY Lung damage Lung damage

is caused due is caused due to the high to the high pressure of pressure of the Oxygen.the Oxygen.

It causes It causes convulsionsconvulsions

2. NITROGEN NARCOSIS2. NITROGEN NARCOSIS Synonym: “The Raptures of the Synonym: “The Raptures of the

Deep”Deep” Symptoms & Signs:Symptoms & Signs:

• A sense of ‘Euphoria’:A sense of ‘Euphoria’: ““All is well with me!”All is well with me!”

• Impaired judgment & performance.Impaired judgment & performance.

3. HIGH PRESSURE NERVOUS 3. HIGH PRESSURE NERVOUS SYNDROME (HPNS)SYNDROME (HPNS)

TremorsTremors SomnolenceSomnolence Decreased manual dexterityDecreased manual dexterity Cause:Cause:

• Xenon, Argon, Neon & Nitrogen act as Xenon, Argon, Neon & Nitrogen act as anesthetics at high pressures.anesthetics at high pressures.

4. AIR EMBOLISM4. AIR EMBOLISM Due to sudden increase in pressure, air is Due to sudden increase in pressure, air is

dissolved in body fluids.dissolved in body fluids. It then comes out when the pressure It then comes out when the pressure

decreases.decreases. It comes out as bubbles which may go out It comes out as bubbles which may go out

as air emboli.as air emboli. These emboli can cause sudden death.These emboli can cause sudden death. This happens in sudden leak in This happens in sudden leak in

pressurization in aircraft.pressurization in aircraft.

CAISSON’S DISEASECAISSON’S DISEASE Synonyms: Decompression Sickness,Synonyms: Decompression Sickness, “ “Bends”Bends” Cause: the bubbling out of Nitrogen Cause: the bubbling out of Nitrogen

as the person rises up.as the person rises up. At the tissue level:At the tissue level:

• PainsPains• Paresthesias: Abnormal sensationsParesthesias: Abnormal sensations• Pruritus: ItchingPruritus: Itching

CAISSON’S DISEASECAISSON’S DISEASE Bubbling of Nitrogen in the Blood causes:Bubbling of Nitrogen in the Blood causes:

• ChokesChokes: Pulmonary Embolism: Pulmonary Embolism

• StrokesStrokes: Cerebral Vessel Embolism.: Cerebral Vessel Embolism. Air embolus gets stuck in cerebral Air embolus gets stuck in cerebral

blood vessels causing paralytic stroke. blood vessels causing paralytic stroke. Also called Cerebro-vascular accident Also called Cerebro-vascular accident

(CVA)(CVA)

CAISSON’S DISEASE: CAISSON’S DISEASE: TREATMENTTREATMENT

Recompression followed byRecompression followed by

S l o w…S l o w…

DecompressionDecompression

EFFECTS

OF

DEEP

SEA

How to go down into the depths?How to go down into the depths?

Use SCUBA:Use SCUBA: SS elf elf CC ontained ontained UU nderwater nderwater BB reathing reathing AA pparatus pparatus

SCUBA!SCUBA!

SCUBASCUBA Invented in 1943.Invented in 1943. By Jacques CousteauBy Jacques Cousteau Has two cylinders containing compressed Has two cylinders containing compressed

air.air. They are connected by tubes with valves.They are connected by tubes with valves. Hose pipe connects these cylinders to a Hose pipe connects these cylinders to a

demand valvedemand valve Through this valve, air reaches the gas Through this valve, air reaches the gas

mask. mask.