DIVING & LUNG

DR TINKU JOSEPH

DM ResidentDepartment of Pulmonary Medicine

AIMS, Kochin

Email-: tinkujoseph2010@gmail.com

Contents

Scuba Diving –Introduction

Equipments

Gas laws

Pathologies & diving injuries.

What Does it Mean? History?

SCUBA – Self Contained Underwater Breathing Aparatus

Long history dating back from 332 BC

Modern fins, mask and snorkel tubes were developed by fishermen from America, Russia, France and England in the 1920s and 1930s

History continued

Recreational SCUBA Diving began between 1942 - 1943, after Emile Gagnan and Captain Hacques –Yves Cousteau developed the self-contained “Aqua-Lung” and new regulator that was automatic.

Cousteau took many successful, experimental dives with his friends, wife and two sons, making this an experimental family trip and experience.

Introduction

SCUBA diving accidents are fairly uncommon.

In experienced divers have a higher incident rate of injury.

Emergencies can occur on the surface, one meter of water, or at any depth.

More serious emergencies usually follow a dive.

Introduction

Behavior of gases and pressure changes during descent and ascent.

Clinical manifestations seen during diving or up to 24 h after it.

Equipment

Mask- Device covering eyes and nose, allowing you to see underwater

Fins – Device put on the feet to extend the kicking motion underwater.

Equipment continued

BCD or BC – (Buoyancy compensator device) Device/jacket that controls buoyancy up or down

Regulator – Device that delivers air to you on demand at reduced pressure

Equipment continued

Pressure gauge – (SPG-Submersible Pressure Gauge) Device that tells diver how much air they have left

Weights – Lead weights used to weigh down divers for depth decent

Equipment continued

• Snorkel – Device used to breath air close to or on the surface of the water

Body suit – Warm temperature suit that protects the body against abrasions and stings

Equipment continued

Wet suit – Insulated suit used to keep the body temperature in

Dry suit – Used to keep the diver dry and warm in colder temperatures

Underwater breathing

Regular breathing makes use of differences in air pressure

The water above a diver increases the atmospheric pressure. Therefore,

Air must be pressurized to be able to breathe at a pressure of more than one Atmosphere (air pressure at sea level).

(This is also why you have to pop your ears as you descend.)

Physical Principles of Pressure

Density of the water can be equated to pressure, which is defined as the weight or force acting upon a unit area.

Fresh water exerts a pressure of 62.4 pounds over an area of one square foot (salt water is 64 pounds). Stated as pounds per square inch (psi)

At sea level humans live in an atmosphere of air, or a mixture of gases, and they exert a pressure of 14.7 psi.

Gas Laws

Gas Laws

Boyle’s Law

“For any gas at a constant temperature, the volume of the gas will vary inversely with the pressure, and the density of the gas will very directly with the pressure.”

If T= constant, then V 1/P and Density P

(Never hold your breath!)

Charles’s LawFor any gas at a constant pressure, the

volume of the gas will very directly with the absolute temperature.

If P= constant, then V T

Or

For any gas at a constant volume, the pressure of the gas will vary with the absolute temperature.

If V= constant, then P T

Henry’s Law The amount of any given gas will dissolve in a

liquid at a given temperature is proportional to the partial pressure of that gas in equilibrium with the liquid and the solubility coefficient of the gas in the particular liquid.

An increase in pressure will increase absorption

(Oxygen in your blood dissolves at a given pressure.)

Henry's Law

Gas molecules will dissolve into the blood in proportion to the partial pressure of that gas in the lungs.

Henry’s Law

• At sea level, the dissolved gases in the blood and tissues are inproportion to the partial pressures of the gases in the person's lungs at the surface. • As the diver descends,the ambient pressure increases, and therefore the pressure of the gas inside the lungs increases.

Main Pathologies

Barotrauma – Ear, Sinus, Pulmonary & Air Embolism

Decompression sickness

Pulmonary edema

Pharmacological and toxic effects of increased partial pressures of gases

Ear Barotrauma

Most common disorder among divers (Middle ear involvement).

Unable to equilibrate the pressure between the nasopharynx and the middle ear through the eustachiantube can result in middle ear pain.

Ringing in the ears, dizziness, hearing loss.

In severe cases, rupture of the ear drum can occur.

Sinus Barotrauma

Second most common disorder among divers.

During descent, increase in ambient environmental pressure can lead to mucosal engorgement, edema and inflammation producing blockage of the sinus ostia.

Frontal sinus – most commonly affected.

Headache, epistaxis.

Pneumocephalus.

Air Embolism

Any person using SCUBA equipment presenting with neurologic deficits during or immediately after ascent, should be suspected of air embolism

Form of barotrauma of ascent.

Very serious condition in which air bubbles enter the circulatory system through rupture of small pulmonary vessels.

Air can also be trapped in blebs, air pockets, within the pulmonary tissue

Air Embolism- Pathophysiology

Arterial gas embolism is the most serious potential sequel of pulmonary barotrauma.

Arterial gas emboli can result from any of three processes:

1. Passage of gas bubbles into the pulmonary veins and from there into the systemic circulation

2. Development of venous gas emboli (either from barotrauma or decompression sickness), which overwhelm the filtering capacity of the pulmonary capillaries to appear in the systemic arterial circulation.

3. Development of venous gas emboli that reach the arterial circulation "paradoxically" via a functional right-to-left shunt, such as a patent foramen ovale.

Reach the systemic arterial circulation.

Gas emboli typically break up as they reach vascular branch points.

Lodge in vessels with diameters ranging from 30 to 60 µm.

They produce distal ischemia and local activation of inflammatory cascades.

Air Embolism-Pathophysiology

Air Embolism-Clinical features

Cardiac-: Dysrhythmias, myocardial infarction, and/or cardiac arrest (0.5ml air can cause)

CNS-: focal motor, sensory, or visual deficits to seizures, loss of consciousness, apnea, and death.

Skin-: cyanotic marbling of the skin, focal pallor of the tongue.

Renal-: hematuria, proteinuria, and renal failure.

Uterine & GI bleeds

Air Embolism- Treatment

Immediate administration of 100 percent oxygen.

Shift to hyperbaric oxygen facility as soon as possible.

Widen the pressure gradient for nitrogen between the bubble and the circulation.

Accelerate re-absorption of gas bubbles, and hydration to decrease vascular obstruction and augment collateral flow.

Divers Alert Network at (919) 684-9111.

Air Embolism-Treatment

1. Assess ABCs.

2. Administer oxygen.

3. Place patient in left lateral Trendelenburg position/Supine position

4. Monitor vital signs frequently.

5. Administer IV fluids.

6. Corticosteroid.

7. Lidocaine.

8. combination of prostacyclin, indomethacin, and heparin h

Pneumomediastinum

Alveolar rupture- gas can dissect along the perivascular sheath into the mediastinum.

Clinical Features: Substernal chest pain. Irregular pulse. Abnormal heart sounds. Reduced blood pressure/narrowing pulse pressure. Change in voice. May or may not be evidence of cyanosis. Crepitation in the neck Hamman’s sign

Pneumomediastinum - Treatment

Administration of high-concentration oxygen via non-rebreathing face mask

Treatment generally ranges from observation to recompression

Pneumothorax

Relatively uncommon

Developing in only approximately 10 percent of episodes of pulmonary barotrauma

Patients with a history of spontaneous pneumothorax, bullae, or cystic lung disease are at increased risk.

Injuries at the Bottom

• Nitrogen narcosis.

Caused by raised partial pressure of nitrogen in nervous system tissue.

Usually occurs at depths greater than 100 feet.

Rapture of the deep, the martini effect.

Direct toxic effect of high nitrogen pressure on nerve conduction.

Variable sensation but always depth-related.

Nitrogen Narcosis

Some divers experience no narcotic effect at depths up to 40 m. whereas others feel some effect at around 25 m.

The diver may feel and act totally drunk.

Takes the regulator out of their mouth and hands it to a fish !

Pressure DisordersDecompression Sickness (Bends)

Condition that develops in divers subjected to rapid reduction of air pressure after ascending to the surface following exposure to compressed air.

Decompression Sickness (Bends)

"caisson disease“

First recognized in 1843 among tunnel workers following return from the compressed environment of the caisson to atmospheric pressure.

Term "the bends" is frequently applied to this illness.

Laborers with decompression sickness sometimes walked with a slight stoop.

A posture affected by female socialites around the time of construction of the Brooklyn Bridge in the late 19th

century.

Diver descends -: breathes air under increased pressure.

Tissues become loaded with increased quantities of oxygen and nitrogen as predicted by Henry's law.

Diver ascends-: the sum of the gas tensions in the tissue may exceed the ambient pressure.

Leads to the liberation of free gas from the tissues in the form of bubbles.

Pathophysiology

The liberated gas bubbles can alter organ function by blocking vessels, rupturing or compressing tissue, or activating clotting and inflammatory cascades.

The volume and location of these bubbles determine if symptoms occur or not.

Effects on the body can be direct or indirect.

Pathophysiology

Direct Effects

Intravascular: blood flow will be decreased, leading to ischemia or infarct.

Extravascular: tissues will be displaced, which further results in pressure on neutral tissue

Audiovestibular: air can diffuse into the audiovestibular system, causing vertigo

Indirect Effects

Surface of air emboli may initiate platelet aggregation and intravascular coagulation

Extravascular plasma loss may lead to edema

Electrolyte imbalances may occur

Lipid emboli are released.

General factors relating to development

Cold water dives

Diving in rough water

Overstaying time at given dive depth

Dive at 25 m. or greater

Rapid ascent – panic, inexperience, unfamiliarity with equipment.

Flying after diving – 24 hour wait is recommended.

Driving to high altitude.

Individual factors relating to development

Age – older individuals.

Obesity.

Fatigue – lack of sleep prior to dive

Alcohol – consumption prior or after dive

History of other medical problems .Rt to lft shunt

COPD, Asthma, prior pneumothorax, thoracic surgery, IHD, pregnancy, Inguinal hernia, Panic disorders

Presentation

Decompression sickness divided into two types based on the presenting signs and symptoms.

Type I

Usually referred to as the “bends”.

Musculoskeletal-: Patient experiences pain (joints). Caused by expansion of gases present in the joint space. (Elbow & shoulder)

Skin manifestations -: pruritus (itch), localized erythema.

Lymphatic-: lymphadenopathy and localized edema.

Neurologic

60% of divers

Damage to spinal cord.

Paresthesias and weakness

Paraplegia

Loss of bladder control

Memory loss

Ataxia

Visual and speech disturbances.

Pulmonary

Venous gas embolism (5%)

Gas bubbles – occlude portions of Pulmonary circulation.

Chest pain, dyspnea

Right ventricular outflow obstruction

Circulatory collapse

Type IIBroad spectrum of complaints and could include symptoms of Type I

DECOMPRESSION SICKNESS SEQUENCE

General Symptoms of Decompression Sickness

Extreme fatigue

Joint pain

Headache

Lower abdominal pain

Chest pain

Urinary dysfunction

Vertigo and ataxia

Pruritus

Back pain

Paresthesias

Paralysis

Dysarthria

Frothy, reddish sputum

Dyspnea

Treatment

Hydration

Administration of 100 percent oxygen

Positioning the patient in the left lateral decubitus(Durant's maneuver).

Mild Trendelenburg (bed angled downward toward head) position in an effort to restore forward blood flow by placing the right ventricular outflow tract inferior to the right ventricular cavity, permitting air to migrate superiorly to a non obstructing position

Hyperbaric oxygen therapy – definitive treatment

In a recompression chamber initiated as quickly as possible.

Time to initiation of treatment is one of the main determinants of outcome .

Hyperbaric oxygen therapy decreases the volume of air bubbles according to Boyle's law.

Provides oxygenation to hypoxic tissue by increasing the dissolved oxygen content of arterial blood.

Treatment

Plasma nitrogen concentration decreases, increasing the gradient of nitrogen from bubble to plasma, thus accelerating the absorption of bubbles.

Hyperbaric therapy should be undertaken for at least four hours.

Bubble elimination may be poor in areas of reduced flow where edema and sludging are present.

HYPERBARIC OXYGEN CHAMBER

Contraindications Pregnancy Inner ear infection Tympanic membrane rupture Upper respiratory infection Sinus conditions Lung disease Asthma Seizure disorders Optic neuritis Pneumothorax

POTENTIAL COMPLICATIONS

HYPERCAPNIA ABSORPTIN ATELECTASIS DRYING & CRUSTING OF SECRETIONS PULMONARY OXYGEN TOXICITY -Decreased hypoxemic drive and increased VD in

COPD. -Mucosal damage due to lack of humidity RETROLENTAL FIBROPLASIA CEREBRAL O2 TOXICITY Seizures (hyperbaric) FIRE (airway fires) IGNITION HAZARD. RISK OF RESPIRATORY DEPRESSION IN SOME PATIENTS

WITH COPD IF HIGH CONCENTRATIONS OF OXYGEN ADMINISTERED (CO2 RETAINERS).

Complete resolution of symptoms in Type II decompression sickness 75% of cases

16% - residual symptoms for up to three months

Adjunctive therapies-: NSAID, anticoagulants, and glucocorticoids.

Treatment

General Assessment of Diving Emergencies

• Early assessment and treatment.

• Must develop the diving history or profile. This includes:

1. Time at which the signs and symptoms occurred

2. Type of breathing apparatus utilized

3. Type of hypothermia protective garment worn

Diving History

4. Parameters of the dive:

* Depth of dive

* Number of dives

* Duration of dive

5. Aircraft travel following a dive

6. Rate of ascent

7. Associated panic forcing rapid ascent

8. Experience of the diver

9. Properly functioning depth gauge

Diving History

10. Previous medical diseases

11. Old injuries

12. Previous episodes of decompression illness

13. Use of medication

14. Use of alcohol

• This history will assist in determining if the diver has incurred a pressure disorder

Conclusion

Recreational SCUBA diving continues to increase in popularity, and diving-related injuries have increased proportionally.

Barotrauma is the most common form of diving-related injury.

Decompression sickness occurs when a diver returns to the surface and gas tensions in the tissue exceed the ambient pressure, leading to the liberation of free gas from the tissues in the form of bubbles.

The liberated gas bubbles can alter organ function by blocking blood vessels, rupturing or compressing tissue, or activating clotting and inflammatory cascades.

Treatment of significant decompression sickness includes hydration, administration of 100 percent oxygen, positioning the patient to improve forward blood flow, andhyperbaric oxygen therapy.

Conclusion