Prehospital ultrasound is the specialized application of ultrasound

Ultrasound

Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...

 by emergency responders

Emergency service

Emergency services are organizations which ensure public safety and health by addressing different emergencies. Some agencies exist solely for addressing certain types of emergencies whilst others deal with ad hoc emergencies as part of their normal responsibilities...

, such as paramedics, to guide immediate care and first aid

First aid

First aid is the provision of initial care for an illness or injury. It is usually performed by non-expert, but trained personnel to a sick or injured person until definitive medical treatment can be accessed. Certain self-limiting illnesses or minor injuries may not require further medical care...

 procedures. Like conventional ultrasound, it is a device that produces cyclic sound pressure

Sound pressure

Sound pressure or acoustic pressure is the local pressure deviation from the ambient atmospheric pressure caused by a sound wave. Sound pressure can be measured using a microphone in air and a hydrophone in water...

 to penetrate a medium (usually flesh, in this instance) and reveal details about the inner structure of the medium.

'Emergency ultrasound

Emergency ultrasound

Emergency ultrasound is the specialized application of point of care ultrasound by emergency physicians in an emergency department.- Emergency department ultrasound versus radiology ultrasound :...

" is the use of point-of-care ultrasound by Emergency Physicians.

Differences between prehospital ultrasound and conventional ultrasound

Many emergency physicians now view screening ultrasound as a tool, and not a procedure or study. It is primarily used to quickly and correctly ascertain a limited set of internal injuries, specifically those injuries where conventional methods of determining them, such as trauma to the torso or heart, would either take too long, require too much time to prepare, or introduce greater risk to the patient.

While conventional ultrasound can be a lengthy process, and is usually conducted with non-mobile units and advanced image filtering and manipulation built into the unit, emergency ultrasound is as simple and quick to operate as possible, and narrowly focused on a small set of criteria.

Uses of prehospital ultrasound

The primary uses of prehospital ultrasound are determining the severity of fluid or trauma to the midsection, determining immediate trauma or penetration of the heart, and to process sources and extent of internal bleeding

Internal bleeding

Internal bleeding is bleeding occurring inside the body. It can be a serious medical emergency depending on where it occurs , and can potentially cause death and cardiac arrest if proper medical treatment is not received quickly....

. Specific implementations vary, some areas use the German originated FAST SCAN system which focuses on fluids in the paracolic gutter and the Douglas and Morrison pouch. Others focus more on cardiac ultrasounds.

prehospital ultrasound procedures

In most cases, EMT's will deploy a portable unit. In every instance, an attempt is made to find the area best suited to an ultrasound and utilize bare skin if possible. Resolution is vastly decreased if soundings must be made through any form of clothing.

There are two main areas of emergency ultrasound. The Focused Assessment with Sonography for Trauma (FAST) exam

Focused assessment with sonography for trauma

Focused Assessment with Sonography for Trauma is a rapid bedside ultrasound examination performed by surgeons and emergency physicians as a screening test for blood around the heart or abdominal organs after trauma.The four areas that are examined for free fluid are the perihepatic space...

 focuses on trying to ascertain if there is internal bodily fluid

Bodily fluid

Body fluid or bodily fluids are liquids originating from inside the bodies of living people. They include fluids that are excreted or secreted from the body as well as body water that normally is not.Body fluids include:-Body fluids and health:...

 in blunt abdominal trauma

Blunt trauma

In medical terminology, blunt trauma, blunt injury, non-penetrating trauma or blunt force trauma refers to a type of physical trauma caused to a body part, either by impact, injury or physical attack; the latter usually being referred to as blunt force trauma...

, in the areas between organs, which is a sign of severe internal injury. CARDIASOUND is used to attempt to find blockages, clots, or penetrations of the heart. Both systems are scanning methodologies, they use identical equipment.

Prior text

Strengths of prehospital sonography

1. It images muscle, soft tissue
   Soft tissue
   In anatomy, the term soft tissue refers to tissues that connect, support, or surround other structures and organs of the body, not being bone. Soft tissue includes tendons, ligaments, fascia, skin, fibrous tissues, fat, and synovial membranes , and muscles, nerves and blood vessels .It is sometimes...
   
   , and bone surfaces very well and is particularly useful for delineating the interfaces between solid and fluid-filled spaces, unlike most other methods of trauma diagnosis, which are little more than educated guesses.
2. It renders "live" images, where the operator can dynamically select the most useful section for review, and narrows down the problem area, rather than having to wait until the patient is at the hospital.
3. It has no known long-term side effect
   Adverse effect
   In medicine, an adverse effect is a harmful and undesired effect resulting from a medication or other intervention such as surgery.An adverse effect may be termed a "side effect", when judged to be secondary to a main or therapeutic effect. If it results from an unsuitable or incorrect dosage or...
   
   s and rarely causes any discomfort to the patient.

Weaknesses of prehospital sonography

1. Sonographic devices have trouble penetrating bone. For example, sonography of the adult brain is very limited. This means that in terms of trauma diagnosis involving concussions, sonography will not work.
2. The depth penetration of ultrasound is limited, making it difficult to image structures deep in the body, especially in obese patients, which can be compounded by thick or obscuring clothing that can't be removed out of fear of harming the patient.
3. The method is operator-dependent. A high level of skill and experience is needed to acquire good-quality images and make accurate diagnoses, which is one more skill that a limited EMS team must develop. Since most EMS teams are small and suffer high turnover, retaining qualified personnel can be difficult.