TDI Inspiration and Evolution Closed Circuit Rebreather Diver Course

HYPEROXIA Too much oxygen results in O 2 toxicity risk Inspiration/Evolution alarm is set at a PPO2 of 1.6 or above Track O 2 toxicity per NOAA tables (see manual) At a default setpoint of 1.3, NOAA limit = 180 minutes - But 80% of that is 144 minutes Do not exceed 80% of CNS and OTU tables Need to monitor CNS% and OTU’s carefully on multi-dive days or multiple repeat dive days Physiology – A Reflection for the CCR Diver

SYMPTOMS OF HYPEROXIA CONVENTID –CONConvulsions –VVisual disturbances/Tunnel vision –EEars ringing (Tinnitus) –NNausea –TTingling or twitching (facial) –IIrritability –DDizziness or vertigo Physiology – A Reflection for the CCR Diver

PULMONARY TOXICITY O 2 causes the alveoli surfaces in the lung to dry out thus slowly reducing lung efficiency OTUs – 1 minute of 100% oxygen breathing at the surface Happens above a PPO 2 of 0.5 thus very real danger for CCR and Inspiration/Evolution diving Physiology – A Reflection for the CCR Diver

HYPOXIA Occurs if the PPO 2 drops below 0.16 at any time Real danger on ascent if solenoid fails Real danger if Oxygen tank is off or empty Symptoms can typically be breathlessness and panting, and lack of co-ordination Unconsciousness resulting in drowning can be sudden and without warning Physiology – A Reflection for the CCR Diver

CNS TOXICITY AND OTU’s Real danger of convulsing and drowning if your CNS is not monitored properly Always know the PPO 2 in the loop and do a diluent flush to check any odd readings Track your CNS % and OTU’s on the NOAA tables in your manuals Physiology – A Reflection for the CCR Diver

ASPHYXIA Like strangulation it is caused by a shortage of oxygen and buildup of CO 2 Restrictions in the breathing loop like a kinked mouthpiece hose can cause it Easily noticed early in a dive Ineffective or exhausted scrubber also can cause asphyxia Eventually results in unconsciousness Physiology – A Reflection for the CCR Diver