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
No comments:
Post a Comment