Hypoxia and hyperventilation and protection system Flashcards

Question

Summary of physiological oxygen requirements

Answer 1

PAO2 55mmHg. >Air at 10000ft >100% O2 at 40000ft PAO2 103mmHg >Air MSL. >100% O2 33700ft

Answer 2

0-10000ft. Air 10000 - 33700ft. Increasing % O2 33700-40000ft 100% O2 >40000ft - 100% O2 + pressure breathing

Answer 3

0-10000ft - air 10000-13000ft - air for 30mins max. 15mins emergency O2 available all pax >13000ft Supplementary O2

Answer 4

Early responses (compensation) - increase ventilation - hyperventilation will alway occur with hypoxia - cardiovascular response Late responses (adaptation) eg climbing a mountain - Metabolic > increase production of 2,- BPG - Haematological >increased EPO > increase HB

Answer 5

SNS response - increase HR and CO - Increase SVR > increase venous return and BP, Pulmonary vasoconstriction Alteration of regional perfusion - Increase coronary blood flow, cerebral blood flow - Decrease renal blood flow, splanchnic blood flow, all other.

Answer 6

Physical effects - muscular in coordination - sensory deficits - touch and vision - hot flushes - Cyanosis - hyperventilation Performance effects - personality change - loss of judgement - loss of self-criticism - Euphoria - loss of short term memory - mental in coordination Late effects - decrease consciousness - Air Hunger - Loss of consciousness - muscle spasms - death

Answer 7

``` < 10000ft - mild or no symptoms (unless of exertion) 10000-15000ft - skilled task impaired - headache pronounced - reduced work capacity ```

Answer 8

The period of time between onset of exposure to reduce oxygen in inspired air and the point when performance is impaired such that effective action is impossible Eg at 25000ft TUC is 3-5min

Answer 9

Altitude Time of exposure Breathing gas Rate of ascent

Answer 10

``` Drugs Alcohol and hangover Smoking Other illnesses Physical fitness Rate of ascent Exercise at altitude Stress and workload Cold - increase metabolic rate and O2 consumption Fatigue - ? Unsure why ```

Answer 11

Oxygenate Aviate Navigate Communicate ``` Don oxygen mask immediately Select 100% Oxygen Select emergency pressure Toggle down/tighten bayonet fittings Check connections - push only Breathe at normal rates and depth Check on others ```

Answer 12

If possible medical personnel to meet aircraft Aircrew to report to medical immediately Comprehensive medical examination by AVMO PM220

Answer 13

``` Oxygen toxicity Oxygen paradox Oxygen trapping - oxygen ear, atelectasis Mission endurance Fire hazard ```

Answer 14

A temporary worsening of hypoxia symptoms with the re-introduction of oxygen Usually mild with flushing and poor performance Occasionally severe with potential for spasm Or rarerly LOC Only transient MOA: hypocapnic cerebral vasoconstriction which takes time to normalise and relief of hypoxic vasoconstriction with O2 resulting in reduced arterial BP

Answer 15

After having 100% oxygen the middle ear is filled with 100% oxygen. The middle ear absorbs with oxygen and due too the lack of nitrogen this reduces the pressure causing a negative pressure. This causes suction of TM and Eusachian tube = pain

Answer 16

Occurs with breathing O2 and using G suit going > +3Gz Type of absorption atelectasis Can cause physiologically significant shunt Symptoms: retrosternal discomfort, cough/ inspiration snatch. Can persist for 24 hours after flight Improves with cough as it increases PEEP to open airway.

Answer 17

``` Rule of 5s Breath in for 5 seconds Hold for 5 seconds Breath out for 5 seconds Rest for 5 normal breaths Repeat up to 5 times A few deep coughs ```

Answer 18

It is an emergency get me down capability Safety pressure is always on Minor over pressure starts at 26000ft Full pressure by 40000ft Breathing technique: in for 2, hold for 2, out for 4 ACBC

Answer 19

Need increased mask tension Distant airways, middle ear, lungs and chest Communication difficulty Irritation of eyes Increase WOB > hyperventilation Circulatory effects - pressure breathing syncope

Answer 20

As breathing faster and/or deeper than needed for the removal of CO2 Results - reduction of CO2 = respiratory alkalosis - increase pH decreases plasma Ca2+ = nerve and muscle function, paraesthesiae in lips and fingers, Carlo-pedal spasm. - cerebral vasoconstriction

Answer 21

``` Tachycardia Reduced BP Hypokalaemia Numbness and tingling of extremities Paraesthesia - unlikely if due to hypoxia Hyperreflexes and muscle cramping Seizures Increase anxiety Increase irritability ```

Answer 22

``` Hypoxia - hypoxic ventilatory response Emotion - pain, stress, anxiety Vibration Motion sickness Anti-G straining Pressure breathing ```

Answer 23

``` Assume hypoxia Oxygenate Aviation Navigate Communicate ``` ``` Don oxygen mask immediately Select 100% oxygen Select emergency pressure Toggle down/tighten bayonet fitting Check connections- push only Control rate and depth of breathing ACBC Descend Smoke and fumes Declare emergency Control rate and depth of breathing - ACBC DASM hypoxia check list ```

Answer 24

B. When recovering on oxygen from profound hypoxia

Answer 25

? Ask lecturer’s as unclear in lecture notes and textbook

Answer 26

Need increased mask tension Distension of airways: upper airways, middle ear, lungs and chest Communication difficulty Irritation of eyes Increase WOB - tendency to hyperventilation Circulatory effects - pressure-breathing syncope.

Answer 27

Ambient pressure eg altitude limitation and cabin pressurisation Supplemental oxygen system - enrichment and pressure breathing

Answer 28

AVMO - PAN/Mayday response - immediate cares - consider causes and consequences - PM220 - physiological incident form - call SAVMO Aircrew - ASR - Sentinel - USN forms if PE in F19 F/G

Answer 29

``` Oxygen purity Minimal dead space Acceptable temperature Dispersion of expirate Reliable Automatic Matches high peak inspiration flow rates Comfortable Minimal resistance to breathing Copes with RD Pressure breathing Leakage and safety pressure Want % of oxygen to adjust with altitude ```

Answer 30

``` Oxygen candle Used in Dixie cup oxygen Exothermic reaction releases oxygen Advantages - small and light - cheap and long shelf life - reliable and intuitive - low risk ``` Problems - finite storage - continuous supply - runs until exhausted - Exothermic production

Answer 31

Advantage - common, simple, cheap and available - no ongoing losses with unused - usually 1800 psi - 10 L Cylinder = ~2210 L Disdvantages - Bulky, heavy. - poses an explosive hazard - finite - needs to be dry as moisture will freeze at altitude

Answer 32

Advantages - 1L of LOX = 840 L of O2 = saves on space and weight - low risk of explosive hazard - limited use Disadvantage - logistics are troublesome - inefficient with ongoing losses - expensive to refil - Contamination

Answer 33

It is a molecular sieve using Zeolite - filter out Nitrogen Requires bleed air to enter and drive the filtering process Types - Cobham - F/A-18F, E/A-18G - product gas is always high FiO2 - no dilute. 2 sieve beds - Honeywell - Hawk, PC-21, F-35. Product gas is regulator gas mix. Deliver cleaner and drier product

Answer 34

Will improve - hypoxia, DCI, contamination per se Will not improve - Hyperventilation, anxiety, atelectasis

Answer 35

Structurally: oxygen store, mass flow regulating device, simple hose and mask - 100% oxygen all the time Inefficient and wasteful Used reservoirs systems in Dixie cups

Answer 36

``` Automatic air dilution - economical, 100% oxygen possible Barostatic control safety pressure Inspiration demand ```

Answer 37

``` Inlet port Non return inspiration valve Compensation tube Ice guard Face piece of mask Valve seat Valve plate Springs Compensation chamber Diaphragm Piston Outlet snout ``` Anti-suffocation valve PB toggle Reflected seal

Answer 38

``` 100% O2 constant flow One size fits all Duration 10mins Tethered, no mobility Maintain PO2 at Tracha 83mmHg ```

Answer 39

Pressure - ensure enough oxygen pressure and quantity Regulator Indicator - check flow indicator eg Doll’s eye Connections - push in to ensure secure Emergency - ensure emergency oxygen is ready, Brief passengers on location and proper use.