The Lungs - Potential Problems While Diving (Part 2)

As you can recall the part 1 covered the Air gas embolism. This blog will cover the last three: Pneumothoraz, mediastinal Emphysema, and Subcutaneous Emphysema. Along with this a covering of basic first aid procedures.

PNEUMOTHORAX
If the overpresurized lung tears at it surface, the expanding air leaks between the lungs and the pleural lining (chest wall), causing the lung to collapse, either partially or entirely. This collapsed lung is called a pneumothorax.

This is not nearly as life threatening as an AGE because the victim, in most cases, still has a working lung to breathe from. This collapse lung causes severe chest pain, and may cause the victim to cough up blood.

There is another form of this condition called spontaneous pneumothorax. This occurs with out the expansion of the lungs but through a weakness in the lung itself. This causes a sudden tearing and collapse of the lung.

This condition is uncommon, but can be more serious than the standard pneumothorax. especially if it happens underwater. This type can be aggravated on ascent, when the air pressing on the collapsed lung expands, increasing the pressure of the injured lung.

Since spontanous pneumothorax tends to recur, it inhibits further diving till surgery is performed to correct the problem. Since out a physician who specializes in pulmonary dive medicine. CLICK ON THE PICTURE FOR A BETTER VIEW


MEDIASTINAL EMPHYSEMA

Mediastinal means center of the chest.. This is sometimes called pneumomediastinum, is far less serious that air gas embolism and pneumothorax

This condition, air accumulating in the mediastinum presses on the heart and major blood vessels interfering with circulation. A victim may feel faint and short of breath due to impaired circulation. CLICK ON THE PICTURE TO SEE THE AIR BUBBLES IN THE MIDDLE OF THE CHEST.

SUBCUTANEOUS EMPHYSEMA

This occurs frequently with mediastinal emphysema as air seek its way from the mediastinum, and folowing the path of least resistence, into the soft tissues at the base of the neck.

Air accumulates under the skin in this area. This causes the victim to feel a fullness in the neck and to experience a voice change. The skin may crakle if touched. CLICK ON THE PICTURE TO SEE THE AIR RISE TO THE NECK REGION.

FIRST AID

The first aid for both the decompression sickness and lung overexpansion injuries are the same. You can say that the first aid for the Decompression illess injuries are the same. In fact you do not have to determine on site which you are dealing with to start giving aid to the diver.

Give 100% oxygen to the diver

Simply put, breathing 100% O2 accelerates diffusion of nitrogen from the body to slow and reverse bubble growth, and help bubble elimination. Breathing oxygen also raises the blood oxygen levels and maximizes the effectiveness of the blood that does reach the affected areas. Make sure the air ways are clear and treat for CPR if needed. The best first aid is to get them to a medical facility for proper care.


Now to the lung injuries FIRST AID

Three out of the four conditions are not immediately life threatening, the presence of any of these conditions indicates a lung over-expansion injury has occured. The AGE is the most life threatening and therefore when first aid is given, they treat any of these conditions as though they have AGE.

AGE needs immediate compression to diminish the bubbles in the bloodstream and force them into solution. This restores blood flow to the tissues. None of the other conditions require decompression, provided there is no AGE.

Pneumothorax requires surgical removal of the air from between the collapsed lung and the pleural lining, followed by a lung reinflation.

Mediastinum and subcutaneous emphysema will dissipate on their own as the blood slowly reabsorbs the trapped air. Breathing oxygen can speed up the reaborbtion process.

REMEMBER DO NOT HOLD YOUR BREATH WHILE DIVING ON SCUBA.

The Lungs - Potential Problems While Diving (Part 1)

There are 4 types of injuries that can occur to the lungs by holding your breath on ascent.

LUNG EXPANSION INJURIES IN GENERAL

Most body air spaces respond to pressure decrease with neither complications nor voluntary action by the diver. The Lungs respond to this as well, provided the diver breathes continuously to them keep equalized to the declining pressures. If the diver holds their breath or air traps within a section of the lungs, and as pressure declines expanding air will almost always cause an over-expansion injury.

The "GOLDEN RULE" in diving - never hold your breath while on scuba and while underwater. Panic and ignorance have been the causes of divers holding their breath. Nausea, choking and carelessness have also been causes to this as well.

Obstruction in the lungs may also trap air in certain parts and in effect "hold its breath." A chest cold, or respiratory infection can cause mucus accumulation and cause an obstruction. Smoking has also been implicated in these injuries.

Lung injuries can occur from even a small amount of over-pressurization. Research has shown that starting with full lungs, holding ones breath and surfacing can have an injury in as little as a 3 to 4 feet distance.

Rather than the lungs bursting like a balloon, an over-pressurization tears the lungs. The injury does not occur from the tear to the lungs, but from the air escaping and entering the tissues and / or the bloodstream. Lung injuries can result in 1 of 4 ways: Air embolism, Pneumothorax, mediastinal emphysema, and subcutaneous emphysema.

Any lung injury causes pulmonary capillaries and alveoli to rupture, mixing blood and air in the lungs. This results, often times, to the victim coughing up blood.

AIR EMBOLISM (AGE)

This is the most serious type of lung over-pressurization injury. This results was the air enters the blood stream from a rupture of the alveoli into the pulmonary capillaries, causing an air embolism or arterial gas embolism. Click on image for larger view.

An embolism is any foreign object that enters the bloodstream that blocks its flow. An air embolism is the same but now it is an air bubble that blocks the flow of blood. So as you ascend the once small bubbles become larger and larger due to the expanding nature of the ascent. This is a bubble on the arterial side of the circulation.

Air enters the bloodstream in the lungs flows through the pulmonary vein into the heart, to the left side of the heart into the aorta and then the arterial system. This air bubble can lodge almost anywhere in the circulatory system - can cause severe damage by blocking blood flow to the tissue.

The first main branch off the aorta which include the carotids. The carotids supply the majority of blood to the brain. If bubbles travel into the carotids, which is likely, they will go to the brain and cause cerebral air embolism.

The bubbles deny the brain of oxygenated blood, which causes a stroke. The symptoms include dizziness, confusion, shock, personality changes, unconsiouness, and death. Compared to DCS, the effects of cerebral air embolism and other lung injuries tends to be rapid and dramatic. DCS tends to be delayed.

If the bubbles were to miss the carotids and block the coronary arteries, the result would be a heart attack.

Splash Dive Center, Ron Carmichael Owner Expert Cave Diving Instructor Talks About How to Dive the Caves

25 S. Quaker Lane
Alexandria, VA 22314
Phone: (703) 823-7680

Ron spoke on how to dive the caves. He explained the difference between cavern and cave diving. What equipment, prior training, and mental attitude do you need to dive caves was discussed. If you find cave dive is a dive you would like to tray and make, then you need to listen to this episode. After it you will have all the information to make an informed decisions about this exiting sport.

Click on any picture and it will take you to Splash Dive Center for more information. This is well worth the click. He has a fantastic web site filled with lots of information.

Boat Diving - Why Dive From a Boat and other Important Information

In this blog I will try to explain the many aspects of diving from a boat and what it takes to get the Boat Diver PADI certification card.

WHY DIVE FROM A BOAT ?
1. Opportunities to dive in areas that could not otherwise reach.
2. Allows you to seek out calm water
3. Entries and exits are easier than diving from shore. Reduced need for long surface swims, meaning that the boat will drop you off just above where you will begin the dive.
4. Less wear and tear on the dive equipment

BASIC BOAT TERMINOLOGY

BOW - Front end toward the front of the boat. Also forward is used.
STERN - Back end towards the rear of the boat. Terms also used are Astern and aft, meaning after the decks.
STARBOARD - Right side of the boat
PORT - Left side of the boat. If you remember left port and in leaving the harbor many help you remember which is port and starboard.
WINDWARD - To the weather side or the side which the wind is blowing
LEEWARD - The side of the boat that is away from the wind.
AMIDSHIPS - Has two meanings, between the two sides of the boat and also between bow and stern of the boat
HEAD - A boat's toilet/restroom
GALLEY - Boat's kitchen
BRIDGE - A raised platform on the boat where the boat is navigated

TYPES OF BOATS
INFLATABLES
Where divers want fast, stable, portable, and inexpensive way to get to the dive sites. Typically they carry 2 - 4 divers. Like a river raft type with 2 sir filled tubes. These are considered small boats.

HARD HULL DAY BOATS
These boats include runabouts, pontoon types, flat tops, small sailboats, skiffs, and other small to medium open air boats. Can carry a large number of divers and equipment.

CABIN CRUISERS
These have minimum accommodations for extended overnight stays. Can carry 6 - 10 divers. They have multiple decks for sitting and enjoying the water.

LIVE - ABOARDS
Very large category boats that will allow many divers to live on the boat for up to 1 week at a time. Usually these boats require a small number of crew members to run the daily duties. The distance range also increases with this type of boat.

SAFETY / EMERGENCY EQUIPMENT

Part of the responsibities of the boat captain is to explain what and where emergency equipment is located. It is also important for the diver to also know this information. The emergency equipment listed is the usual type that is needed on the boat.

1. LIFE PRESERVERS
2. FIRE EXTINQUISGHERS
3. SOUND SIGNALING DEVICES
4. VISUAL DISTRESS SIGNALS
5. FIRST AID KITS
6. OXYGEN EQUIPMENT
7. MARINE RADIO
8. BILGE PUMP

It is Important for every Diver to know where each if these pieces of equipment are located

What is the Difference Betweem DCS and DCI ?

First we must define what we mean by DCS. There is an overall term called Decompression Illness (DCI) which most divers get confused and call decompression sickness (DCS), the same. No it is not the same. DCI is the over all term that has 2 subjects below it: 1) DCS and 2) Lung Over expansion Injuries.

DCS refers to the conditions caused by inert nitrogen gas coming out of solution within the body. Lung Over expansion Injuries refer to those injuries that are caused by holding your breath on ascent. Today's blog in on DCS.

There are basically 2 types: Type I deal with skin and pain only which would include the sub type a) Cutaneous DCS and b) Joint and limb pain DCS. While Type II covers the more life-threatening which are the c) neurological DCS and d) Pulmonary DCS.

A) CUTANEOUS DECOMPRESSION SICKNESS

Bubbles coming out of solution in skin capillaries can cause this type. They show up as a red rash in patches, usually in the shoulders and upper chest areas. Although this type is not serious in and by itself, it could lead to a more serious problem.

B) JOINT AND LIMB PAIN DECOMPRESSION SICKNESS

This type occurs in about 75% of the DCS cases. Bubbles growing around and inside the tendons, ligaments and related muscles are the immediate cause. They really do not know how it happens. Symptoms may be found in one place on the same limb or bilateral symptoms. This type may be serious because it can lead to a mores serious problem.

C) NEUROLOGICAL DECOMPRESSION SICKNESS

Effects on the nervous system produce some of the more serious cases in DCS. Bubbles in the nervous tissue may block blood flow "backing up" the system and reduce arterial flow in the affected areas. This affects the spinal cord most often often causing numbness and paralysis in the lower legs. It tend creeps upwards to affect from the neck down.

Bubbles can also travel to the brain causing a stroke as they block blood flow. These symptoms are similar to those caused by arterial gas embolism. These symptoms are blurred vision, headaches, confusion, unconsiousness, and death.

D) PULMONARY DECOMPRESSION SICKNESS

This is DCS that manifesting itself in the lung capillaries resulting in the onset of life-threatening symptoms. These are rare. Silent bubbles reach the pulmonary capilaries defusing into the alveoli. In some cases, bubbles accumulate faster than they diffuse and can block and back up blood flow to the lungs. With less blood flowing to the lungs, the left side of the heart gets less blood, causing the heart rate to rise and a drop in blood pressure. With no treatment, the circulatory system may fail.

Pulmonary DCS creates breathing pain, assocaited with a short, irritated cough, The victim often feels air starved. This is commonly given the nickname "the Chokes". Symtoms tend to progress rapidly and may lead to shock.

HOW TO AVOID DECOMPRESSION SICKNESS

1. Divers should be familiar with the proper use of dive tables through education by a professional diving instructor.

2. Divers using a computer should follow all manufactor recommendations. Conservatism is always the rule.

3. Factors thought to predipose divers to DCS should be avoided. (Covered in next Blog and talkcast). If some factors can not be avoided, use computers more conservative.

4. Divers should be familiar with first aid for DCS, and learn proper procedures for obtaining medical treatment.

RULES FOR DIVING IF GO BEYOND THE
NO DECOMPRESSION LIMIT (NDL)

1. LESS than 5 minutes over the NDL decompression time
a. Do a REQUIRED STOP at 15 feet for 8 minutes
b. DO NOT dive again for 6 hours (Considered the wash out period)

2. MORE than 5 minutes over the NDL decompression time
a. DO a REQUIRED STOP at 15 feet for 15 minutes
b. DO NOT DIVE for 24 hours

These are just some of the basic points on what decompression sickness is, how to avoid, and what to do in the water if you exceed the decompression times