SMOKING & TECH DIVERS

The long term effects of tobacco smoking are multiple   and   well known to most of us.   I am not to debate them.   It is the immediate effects which,   as a scuba instructor,   concern me.   Upon my refusal to accept   (whom I considered)   a heavy smoker into a Decompression Course,   I felt the need to justify this policy.   I respect   and   accept anyone's moral decisions relating to their bodies as much as I want them to accept mine.   The essence of my policy not to teach DECO   or   any other Technical Course to smokers is based on my perception of how our bodies are overly taxed by tobacco smoke just when the body needs its utmost efficiency to cope with the dangerous tasks of handling gases under very high pressures.

CARBON   MONOXIDE   (CO)   ---   bonds immediately to the hemoglobin (Hgb) to form carbuhemoglobin (HgbCO),   not only because its affinity is more than 200 times stronger than that of Oxygen (O2),   but also because a single cigarette dumps over 40,000 ppm (parts per million)   or   about 4% of CO -- out of which 400-500 ppm reach your blood producing 4-7%HgbCO ... completely eliminating those Hgb cells from its O2 bonding task.   Heavy smokers could have as much as 15% of their blood cells totally out of service.   It takes as many as 8 days to eliminate 75% of contaminated HgbCO from your body.
Needless to mention,   the replacement of O2 by CO significantly curtails the oxigenation of critical tissues which could be at the edge of hypoxic conditions due to blood cell rigidity (as pressure increases)   and   possible acidosis encumbering O2 metabolism.   CO combines with a final metabolic enzyme (cytachrome oxidase, a ferric ion A3) halting cellular respiration in the tissues causing hypoxia.   Anaerobic metabolism in turn produce high lactase acidosis decreasing muscle efficiency.  CO causes atherosclerotic changes in blood vessels,   rises in blood pressure,   increase heart rate   and   bronchial mucous.   This list by itself would be enough to deter ANY diver from puffing a smoke if they want to take a dive ...... not to mention a technical dive.   But there's more ...  the hydrogen sulfide in the cells' mitochondria prevents it from effectively using oxygen in its processes.

NICOTINE --   increase stickiness of blood platelets (a most critical factor when nitrogen bubbles are present in the bloodstream)   and   exacerbates the blood sludging which in turn interferes with blood flow.  Peripheral constriction of blood vessels obstructs off-gassing.
TAR --   has been found in thin layers in the alveoli membrane which interferes with an effective exchange of gases   (O2, N2, CO2, He).   Combined gases in tobacco smoke cause Chronic Obstructive Pulmonary Disease (COPD) in the alveoli;   emphyzema   and   inflamation of lung tissues,   air-trapping lung cysts,   increase of bronchial mucous   and   plugs,   paralysis of cilia (air passages filters)   and   drainage deficiencies.
Other effects under study range from EKG deficiencies,   and   retinal venous engorgement   to accelerated breathing.   As if this wouldn't be enough,   the growing list of effects points to yet another malady ...... many of the above,   either on their own   or   combined,   produce CO2 retention -- and this is the straw that breaks the camel's back!

CARBON DIOXIDE   (CO2) --   has been closely associated with DCS,   Ox-Tox,   N2 Narcosis   and   underwater blackouts.   CO2 retention will immediately act as a cranial vasodilator allowing high PO2 to reach the CNS with increasing probability of convulsions.   It will also produce an increase in gas consumption   and   myocardial contractility.   Its acidic effect on the blood is known to affect,   not only the blood chemistry,   but also the metabolic reactions as well -- leading features in DCS episodes   and   (still unknown how) narcosis.   Other maladies that range from mental impairment to total blackouts have also been blamed on CO2 retention.
Overall,   tobacco users deteriorate the lung linings that decreases the surface area available for gas exchange,   therefore losing pulmonary efficiency.   While most of this goes unnoticed inside a diver,   the consequences are not.   The tech divers body is subject to many strenuous   and   stressful (emotional,   psychological   and   physical)   pressures.   The effects here described are only a partial list of the damage done by tobacco.   The results can only lead towards a personal tragedy.  Every adult is the final decision-maker of their own bodies   and   life -- a conviction  I  accept   and   respect.   I am NOT advocating that smokers should not dive,   their decision is for them to take.   I am just stating that I am not going to be a willing accomplice of their risks.

SMOKERS   BEWARE !!!