Scuba Emergencies (ascent)

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Scuba Diving Emergencies (Ascent)

*rare, but commonly tested topic! 

*includes sinus barotrauma, “face squeeze,” pulmonary barotrauma, decompression sickness, arterial gas embolism, nitrogen narcosis, oxygen toxicity, carbon monoxide toxicity, hypothermia, and even caustic injuries.

*today’s POTD will primarily focus on barotrauma of ascent


Decompression Sickness

·       aka “the bends”

·       Mostly after rapid ascent from diving;  less commonly following high altitude aviation ascent and hypobaric training

·       Onset

  •   symptom onset ~ 6 hours after surfacing, but as quickly as 10 minutes after

·       Pathophysiology

  • Results from the expansion of inert gas (nitrogen>helium) that dissolved in tissues during descent

    • As the pressure of these gases exceeds atmospheric pressure, they bubble and lodge in veins leading to localized venous obstruction and inflammatory cascades

·       Types

  •   Type I

    • Less dangerous

    • Constitutional symptoms

    • Joint/extremity involvement/pain

      • Shoulder, elbow, knee

    • Skin/lymphatic involvement

      • Pruritis, paresthesias, hot/cold disturbances, pittng edema

      • “Scarletiniform” rash secondary to nitrogen passage through sweat glands

      • “Cutis marmorata” marbling purple/blue discoloration  

  • Type II

    • Multiple joint involvement

    • Spinal cord involvement

      • Ascending paralysis/paraesthesias

      • Urinary retention, fecal incontinence, priapis

    • Vestibular involvement

      • Vertigo, tinnitus, hearing loss

    • Pulmonary involvement

      •   Cough, chest pain, sob, hemoptysis

  • Type III

    •   Type II + Arterial Gas Embolism (see below)

    • Essentially stroke symptoms

·       Work up and Management

  • Clinical diagnosis

  •   BGM, full set of labs (cbc, bmp, lfts, pt/ptt, vbg, etoh)

  • Supine, not trendelenberg

  • IVF

  •   “De-nitrogenation” with 100% NRB, to be continued 2 hours after symptom resolution

  •    Hyperbaric therapy for Type II and III

    •   If need to transport, then preferably ground and not air  


Arterial Gas Embolism

·       Can occur after diving, dialysis, pregnancy, etc.

·       Onset

  • AGE from scuba diving occurs during ascent or immediately after

·       Pathophysiology

  • Rapid ascent without exhalation leading to lung volume expansion, alveolar rupture, and gas leakage (air or nitrogen) into the pulmonary veinsàleft heartà systemic circulation

    • Can embolize to different parts of the brain, often cerebral arteries

·       Symptoms

  • Suspect in anyone who’s lost consciousness on ascent or within 10 min of surfacing

    • But symptoms can vary depending on location of embolization (see below)

      • Coronary

        • Dysrhythmia, MI, cardiac arrest

      • Cerebral

        •   Stroke symptoms, visual deficits, seizures

      •    MSK

        • Cyanosis

      •   Renal

        •   Hematuria, proteinuria, ARF

·       Work up and Management

  •    Labs as above

  •   TEE if available

  •   Supine

  •    IVF

  •   100% NRB while transporting to hyperbaric facility, intubate if necessary