Dysbarism (DeCompression Illness)

Please discuss ALL cases of possible barotrauma or drowning with the EM Consultant on call.

The Irish Naval Service provide a recompression service to civilian divers from the 2nd of May. We (CUH Emergency Medicine Service) will be providing clinical advice and support. Doing this will involve the following:

• Divers requiring recompression will first be assessed at CUH emergency department.
• Any investigations or clinical interventions (e.g chest drains etc.) will be done here prior to transferring the patient to the RCC at Hawlbowline.
• The Irish Naval Service will be alerted by us (Medico Cork) as per their SOP.
• The chamber will take about one hour to be readied.
• The diver will be accompanied to Hawlbowline by a nurse at least, and by the clinician (those on this list and/or Dr.John Murphy INS) if necessary.
• It will not usually be necessary for the clinician to be in attendance on site for the treatment.
  

Clinical advice and support are available from the Royal Navy Duty Diving Medical Officer in Portsmouth 0044 7831 151 523. We should of course be in a position to support each other.

It may be necessary to enter the chamber on occasion. Each clinician must have a ‘diving medical’ (including spirometry and audiometry) and have experienced of being compressed to 18m.

Boyle's law

The the volume of a fixed mass of gas is inversely proportional to the absolute pressure (assuming constant temperature)

Henry's law

At a constant temperature the amount of gas that will dissolve in a liquid is proportional to the partial pressure of the gas over the liquid("Heineken law")

Dalton's law

In a mixture of gases, the partial pressure of each gas present is equal to the pressure that gas would exert if it alone occupied the original volume. P(total) = P(1) + P(2) +.....P(n)

 

Pulmonary barotrauma (POIS = Pulmonary Over Inflation Syndrome)

Results in A) Arterial Gas Embolism,  B) Pneumothorax,  C) Mediastinal or surgical emphysema,  D) Pneumoperitoneum

History

• Get as detailed dive history as possible - particularly gas  mixtures used, depth and duration, decompression stops
• Record if symptoms occurred on descent or ascent or how long after dive completed
  • Inner or middle ear (tympanic membrane) trauma usually have difficulty clearing on descent
• Note past medical history (particularly previous DeCompression Illness), respiratory and ENT status

Initial measures

Initial measures aim to increase oxygenation (hasten removal of nitrogen from tissues and treat tissue hypoxia) and hydration (dehydration and haemoconcentration occur due to insensible losses to the environment). AVOID ENTONOX

Airway

• 100% oxygen via face mask to hasten inert gas elimination
• Rapid sequence intubation if airway not protected
• Left lateral position (not head down as may raise intracranial pressure)

Breathing

• Chest drain if pneumothorax, surgical emphysema or pneumomediastinum
• Even if only problem appears to be pulmonary barotrauma, refer to diving medicine unit anticipating 2⁰ deterioration)

Circulation

• IV fluids increase vascular permeability causes third space losses)
• Catheterise if serious

Disability

• Neurological examination (including gait assessment if possible)
• Diazepam for fitting

Referral

Telephone prior to transport to recompression chamber following this agreed protocol. If using helicopter, low altitude (below 200m). Fixed wing aircraft should be pressurised to 1 bar (sea level). There 29 chambers in the UK - 14 civilian and 15 under MoD control

Emergency Recompression facilities in Ireland

• Naval recompression chamber at Haulbowline, Cork (021) 4378777
• Craigavon General Hospital (08 0762 334444)

Other useful numbers

• Irish Coastguard (01) 6620922 or 112 (999)
• Helicopter Rescue Service (01) 4592379/2494
• Irish Underwater Council (01) 2844601
• Duty Diving Medical Officer 0044 7831 151 523

Please discuss ALL cases of possible barotrauma with the on-call Consultant in Emergency Medicine.

Links

• Institute of Naval Medicine, Alverstoke, Gosport, Hamphshire, PO12 2DL (0044 23 9276 8026)
• Duty Diving Medical Officer 0044 7831 151 523
• Undersea Medicine Division of the UK Royal
• Drowning

Content by Prof. Stephen Cusack, Dr Íomhar O' Sullivan, 29/07/2004. Reviewed & edited by Dr ÍOS 01/11/2005, 27/04/2007. Dr Nora McCarthy 06/05/2008. Last review Dr IOS 28/08/11