Understanding and Treating Medical Shock

13 April 2009 By Robin Drake, R.N, MedAire, Inc.

What is medical shock, and under what circumstances might your crew be faced with this potentially life-threatening situation?

Shock occurs when the blood flow to vital organs is critically reduced. This reduction compromises the effective delivery of nutrients to the different tissues and also inhibits the removal of waste that is generated by cell activity.

Major causes of shock include heart attack and uncontrolled internal or external bleeding, but dehydration, severe infection, burns, anaphylaxis (severe allergic reaction), persistent vomiting and diarrhea – all possible scenarios that can and do occur at sea – also can trigger the condition.

Shock symptoms vary and can present in a variety of forms, almost always associated with low blood pressure:

- Faster-than-normal breathing

- Cool, moist, pale skin

- Dusky lips or nail beds

- A rapid, weak or difficult-to-locate pulse

- Dizziness/lightheadedness or episodes of passing out or fainting

- Generalized weakness

- Anxiety, agitation or confusion

- Altered level of consciousness

If a guest or crewmember is experiencing any of the above symptoms, he or she may be suffering from one of five types of shock. Understanding the different categories of shock and knowing how to provide initial first aid treatment can be critical to saving a life.

1. Septic shock is caused by a body-wide, toxic infection that travels via the bloodstream, affecting one or more body systems. Septic shock can occur when an infection is not treated properly or early enough, leading to the presence of bacteria in the blood (bacteremia).

2. Cardiogenic shock occurs when the heart muscle is too weak to properly pump the blood through the body, leading to dangerously low blood pressure. Individuals with heart conditions and the elderly are more susceptible. Often, the cause is a heart attack, when enough heart muscle is injured to cause the “pump” to be less efficient.

3. Neurogenic shock occurs after injury to the spinal cord. Electrical conduction from the brain to the body is disrupted, causing malfunction with the regulatory functions of the body, which may include the respiratory, cardiac, circulatory, digestive and neurological systems. Crew are often at greater risk of spinal cord injuries, given potential falls on slippery deck surfaces that can lead to a direct head strike and spinal compression. Even an electrical shock strong enough to throw a person some distance can cause trauma to the spine and neurogenic shock.

4. Hypovolemic shock is caused by fluid loss, either through persistent vomiting and diarrhea, or by uncontrolled bleeding from trauma. Persistent seasickness can result in severe dehydration associated with vomiting.

5. Anaphylactic shock is an abnormal, exacerbated response to the introduction of an allergen to the body, most often by injection or ingestion. The body, if sensitive to the substance, reacts by causing dilatation of the blood vessels and a consequent drop in blood pressure. Typically, this type of shock is accompanied by local or generalized swelling that can quickly become life threatening – involving the skin, face, gastrointestinal tract and also the upper or lower airways (larynx, bronchi). Allergic reactions can occur when guests and crew are exposed to solvents and cleaning products used on board, as well as from contact with jellyfish and other stinging marine life. The allergy-sensitive food list varies widely from person to person, and a first-time occurrence can come as a surprise and worsen rapidly.

Being able to identify possible shock and making an early call to the yacht’s telemedicine service very well may save a life. A solid understanding of first aid when shock is suspected is also critical.

Depending on the circumstances, here are the first-aid steps to follow:

- Protect the airway and the spinal cord, laying the patient flat to preserve central or “core” circulation to the vital organs

- Apply direct pressure to a bleeding site in order to lessen blood loss caused by trauma

- Provide supportive and comforting measures

- Keep the person quiet and calm until further treatment can take place

Working with a land-based emergency doctor trained in remote diagnosis, you may also be asked to take a blood pressure reading, obtain a pulse and breathing rate, administer oxygen or give oral/intravenous fluids as appropriate.

Your observations and an objective description of how the person will help the telemedicine doctor make basic decisions regarding the first line of treatment, using the medical equipment available on board your vessel.

Robin Drake, RN, a nurse case manager for MedAire’s Global Response Center, has more than two decades’ experience of emergency medical management experience. For more information on MedAire’s telemedicine solutions, visit