Effects of Pressure

1. Effects of Pressure

2. We will cover • Snorkel Diver • Scuba Diver • Thoracic Squeeze • Burst Lung • Ears and Sinuses • Tooth Squeeze • Mask Squeeze • Suit Compression • Toxicity • Nitrogen Narcosis • Summary

3. Snorkel Diver • Air spaces affected • Lungs compressed at depth • On ascent, lungs expand to normal

4. Surface 1 Bar 10 metres 2 Bar 20 metres 3 Bar Thoracic Squeeze

5. Scuba Diver • Air breathed at surrounding pressure • Other effects • Ears • Decompression • Mask squeeze • Loss of buoyancy • Ascent risks • Air consumption • Hypothermia

6. Burst Lung • Described as: Over-expansion and rupturing of lung alveoli with air escaping into the bloodstream or chest cavity • Caused by: • Holding one’s breath during an ascent from depth • Diving with a lung infection or disorder

7. Burst Lung Bubbles in Carotid Artery leading to Brain Bubbles of Air entering the Blood Vessels Ruptured Alveoli and Blood Vessels

8. Ears Ear Drum Eustachian Tube Blockage caused by mucous build-up Blockage caused by inflammation

9. Frontal Sphenoid Ethmoidal Maxillary Opening to Eustachian Tube The Sinuses Cranial Cavity

10. Tooth Squeeze • Air-filled spaces in teeth • Teeth cannot increase/decrease in size with pressure • Causes: • Cavities, • Defective margins of restorations, • Maxillary sinus congestion, • Implosion

11. Tooth Squeeze

12. Surface 1 BAR 10 metres 2 BAR Mask Squeeze

13. Suit Thickness at Surface - 1 BAR At 10 Metres - 2 BAR At 20 Metres - 3 BAR Suit Compression

14. O2, CO & CO2 Toxicity • O2 Toxicity • PPO2 greater than 1.4 bar • Pulmonary and Central Nervous System • CO2 Toxicity • Inadequate ventilation • Stop, Lie Still & Breathe Slowly • CO Toxicity • Compressor malfunction

15. Nitrogen Narcosis • Raised Partial Pressure of Nitrogen = Narcotic Effect • Depth = Intoxicating Effect!

16. Nitrogen Narcosis If suffering from Narcosis Ascend slowly until the symptoms disappear If symptoms persist Abort dive and ascend to surface

17. Summary • Snorkel Diver • Scuba Diver • Thoracic Squeeze • Burst Lung • Ears and Sinuses • Tooth Squeeze • Mask Squeeze • Suit Compression • Toxicity • Nitrogen Narcosis

18. Questions

19. A snorkel diver breathes air • At ambient pressure • At surface pressure

20. A snorkel diver breathes air • At ambient pressure • At surface pressure

21. Tooth squeeze is caused by : • Water on the tooth • Air trapped under the tooth • Surfacing quickly

22. Tooth squeeze is caused by : • Water on the tooth • Air trapped under the tooth • Surfacing quickly

23. Suit compression makes a diver: • Lighter in the water • Heavier in the water • Neutral

24. Suit compression makes a diver: • Lighter in the water • Heavier in the water • Neutral

25. Nitrogen narcosis may be overcome by : • Breathing slower • Ascending to a shallower depth • Lowering the partial pressure

26. Nitrogen narcosis may be overcome by : • Breathing slower • Ascending to a shallower depth • Lowering the partial pressure

27. Burst Lung is caused by : • Inhaling too deeply • Holding breath on descent • Holding breath while ascending from depth

28. Burst Lung is caused by : • Inhaling too deeply • Holding breath on descent • Holding breath while ascending from depth