Wilderness and Rescue Medicine 8th Edition

3 1

Section II: Critical Body Systems

is as serious a problem as a heart attack. In either case the problem is the same: inadequate perfu- sion pressure due to inadequate pumping action of the heart. Field Treatment of Cardiogenic Shock Field treatment options for cardiogenic shock are limited and the patient really needs a hospital. Suspected myocardial ischemia is treated with oxygen, aspirin, and the patient’s own nitroglycer- in if the drug has been prescribed. Even advanced life support (ALS) treatment is very temporary. This is covered in more detail in the Chest Pain chapter. Cardiac trauma requires urgent evacuation to surgical care. ALS field treatment is limited to pericardiocentesis, which is the aspiration of excess blood or fluid from the pericardial sack. Definitive care may require cardiovascular sur- gery. This should be considered in planning your evacuation route and destination. Not all hospi- tals offer this level of surgical care.

The sympathetic form of ASR is the “speed up” response you feel when you are anxious or scared, produced by the release of the hormones epineph- rine (also known as adrenaline) and norepineph- rine. It speeds up the pulse and respiratory rate, shunts blood to the muscles, dilates the pupils, and generally gets the body ready for action. It also stimulates the release of natural hormones that serve to mask the pain of injury. This type of ASR certainly has value to human survival. It allows for extraordinary efforts even in the presence of significant injury. Unfortunately, it also makes the accurate assessment of the patient difficult for the rescuer by hiding pain and alter- ing vital signs. The elevation in pulse and respira- tory rate and change in mental status can mimic the volume shock pattern resulting in high-risk evacuations for low-risk problems. The parasympathetic form of ASR is the faint and nauseous feeling some people experience with pain or the sight of blood. Its effect slows the heart rate enough to cause a temporary loss of perfusion pressure. The evolutionary value of this response is unclear. This form of ASR is generally harmless except in its ability to mimic shock or brain injury, or cause new injury if the patient faints or falls.

General Principles

Cardiogenic Shock Treatment Heart Attack: • BLS; oxygen, aspirin, nitroglycerin as prescribed • Urgent evacuation to ALS and hospital • Coronary care unit Trauma: • BLS and oxygen • Urgent evacuation to ALS care and hospital • Cardiothoracic surgery

15

General Principles

ASR

17

Sympathetic: • Mediated by epinephrine • Increases pulse, respiration, reduces skin perfusion; increases anxiety • Can look like shock or respiratory distress Parasympathetic: • Multiple chemical mediators • Slows pulse, causes fainting • Can look like TBI or other mechanism for mental status changes

*

© 2018 WMA

Acute Stress Reaction Acute stress reaction (ASR) is discussed here because it can look like shock, but it has none of the serious consequences. ASR is the term for the frequent and normal response to emotional stress caused by fear, disappointment, surprise, pain, grief, or any number of other influences. Some texts use the term psychogenic shock for this phenomenon. However, ASR does not cause a significant loss of perfusion pressure or serious critical system problems.

*

© 2018 WMA

The key to recognizing ASR is in the mechanism of injury and the progression of symptoms. ASR can look like shock but can occur with or with- out any mechanism of injury to cause shock. We have all seen people with only minor extremity sprains or superficial wounds become lightheaded, pale, and nauseous. Although they appear to be