Decompression Sickness
OVERVIEW
Decompression sickness, is a form of decompression illness, where a reduction in ambient pressure (‘decompression’) leads to de no intravascular and extravascular bubble formation with pathological consequences
- decompression sickness = ‘small bubbles’
- arterial gas embolism (AGE) is the other form of decompression illness, characterised by ‘big bubbles’ that are introduced into the circulation following alveolar rupture during decompression
- the altitude threshold for DCS is generally 18,000 ft
- most diving is done @ 2-4 atmospheres
PATHOPHYSIOLOGY
Typically affects
- divers
- caisson workers
- aviators
- astronauts
Mechanism
- release of bubbles of inert gas into the blood and tissues with mechanical, embolic and biochemical effects
- hypoxia induced vasoconstriction -> increased pulmonary capillary pressure, alveolar fluid transudation, decreased alveolar fluid clearance
- endothelial activation -> capillary leak
- increased leukocyte adhesion, inflammatory response and reperfusion injury
- vessel obstruction
- tissue distortion causing pain
- embolisation (25% of people have PFO so can embolise to the brain)
CLINICAL FEATURES
- cough -> respiratory failure
Type I Decompression Sickness
- musculoskeletal pain (limbs, shoulders, elbows, hips, knees)
- anorexia
- malaise
- fatigue
- orange appearance of skin from local lymphatic obstruction
- pruritis (ears, trunk, wrists, hands -> trunk)
- cyanosis
Type II Decompression Sickness
- substernal discomfort
- pleuritic chest pain
- tachypnoea
- non-productive cough
- right heart strain
- cardiovascular collapse
- paraesthesia
- full paralysis
- convulsions
- cerebellar signs
MANAGEMENT
Prevention
- no flying for 24 hours after a dive
Proven Benefit
- FiO2 1.0 (enhanced de-nitrogenation)
- CPR
- isotonic fluid resuscitation — dehydration due to capillary leak, cold diuresis and immersion diuresis
- hyperbaric therapy (even very late) — 2-3 atm, repeated until no further benefil
- intubate and fill cuff with saline
Unproven Benefit
- Trendelenburg position (not longer than 30min c/o cerebral oedema)
- avoid glucose IV
- avoid hypertension and anxiety
- corticosteroids
- benzodiazepine for seizures
- aspirin
Questionable Benefit
- Ca2+ blockers
- lignocaine 1mg/kg
- NSAIDS, heparin, prostaglandin
- induced hypothermia
- cerebral venoarterial perfusion
Proven Detrimental
- recompression while submerged
- alcohol
- analgesics
- delayed transport to hyperbaric center
- additional hypobaric exposures
Transfer by helicopter at 300m, on land or pressurize to sea-level
References and Links
- Bennett MH, Lehm JP, Mitchell SJ, Wasiak J. Recompression and adjunctive therapy for decompression illness. Cochrane Database Syst Rev. 2012 May 16;5:CD005277. PMID: 22592704.
- Lynch JH, Bove AA. Diving medicine: a review of current evidence. J Spec Oper Med. 2009 Fall;9(4):72-9. PMID: 20112651.
- McMullin AM. Scuba diving: What you and your patients need to know. Cleve Clin J Med. 2006 Aug;73(8):711-2, 714, 716 passim. PMID: 16913196.
- Sebel PS. 20,000 leagues under the sea. Anesth Analg. 2010 Sep;111(3):589-90. doi: 10.1213/ANE.0b013e3181eb64de. PubMed PMID: 20733161.
- Tetzlaff K, Shank ES, Muth CM. Evaluation and management of decompression illness–an intensivist’s perspective. Intensive Care Med. 2003 Dec;29(12):2128-36. PMID: 14600806.
- Vann RD, Butler FK, Mitchell SJ, Moon RE. Decompression illness. Lancet. 2011 Jan 8;377(9760):153-64. doi: 10.1016/S0140-6736(10)61085-9. Review. PubMed PMID: 21215883.
Critical Care
Compendium
MBBS (Hons), MPH, FACEM, AFRACMA, AdvCertDHM (ANZCA), DipDHM, PGDipClinUS, CCPU
Emergency & Hyperbaric Physician
The Alfred Hospital, Melbourne
Bass Coast Health, Rural Victoria
Graduated with honours from Monash University. Commenced teaching at Monash University as a bedside tutor then clinical skills tutor whilst training in Emergency. Keen interest in ultrasound to help improve diagnostic efficiency and patient outcomes in the emergency setting. Strong advocate for pre-vocational medical trainees as part of the PMCV accreditation team.
Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the Clinician Educator Incubator programme, and a CICM First Part Examiner.
He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.
His one great achievement is being the father of three amazing children.
On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.
| INTENSIVE | RAGE | Resuscitology | SMACC