Emergency ultrasound

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Emergency ultrasound employing point-of-care ultrasound (POCUS) is the application of ultrasound at the point of care to make immediate patient-care decisions. It is performed by the health care professional caring for the injured or ill persons. This point-of-care use of ultrasound is often to evaluate an emergency medical condition, in settings such as an emergency department, critical care unit, ambulance, or combat zone. [1] [2] [3]

Contents

Setting

A portable ultrasound machine used in the prehospital setting HighlandPICT RedJacket.jpg
A portable ultrasound machine used in the prehospital setting

Emergency ultrasound is used to quickly diagnose a limited set of injuries or pathologic conditions, [4] specifically those where conventional diagnostic methods would either take too long or would introduce greater risk to a person (either by transporting the person away from the most closely monitored setting, or exposing them to ionizing radiation and/or intravenous contrast agents). [5] [6]

Point of care ultrasound has been used in a wide variety of specialties and has increased in use in the last decade as ultrasound machines have become more compact and portable. [7] It is now used for a variety of exams in various clinical settings at the person's bedside. In the emergency setting, it is used to guide resuscitation and monitor critically ill persons, provide procedural guidance for improved safety and confirm clinical diagnosis.

In contrast to a comprehensive ultrasound examination, which is typically performed by a sonographer and interpreted by a specialist, point-of-care ultrasound examinations are performed and interpreted by the same clinician and are typically narrower in scope.

Scope

Resuscitation of the critically ill

Point of care ultrasound is sometimes the only option in the evaluation of injured persons who are too ill for transport to other imaging modalities (i.e. computed tomography, or CT scan) or whose illness is so acute that medical decisions in their care need to be made in seconds to minutes. It is also increasingly used to guide and triage care in resource-limited situations, in rural or medically under-served areas. [8]

For people who present signs of traumatic injury, the focused assessment with sonography for trauma or FAST exam is used to assess hypotensive persons for occult bleeding. Traditionally used by emergency physicians and surgeons treating trauma persons, it has also been used by paramedics [9] in combat zones, [2] and for non-traumatic problems such as ruptured ectopic pregnancy. Similarly, emergency ultrasound can also evaluate the lungs for hemothorax (bleeding in the chest), and pneumothorax (a puncture resulting in air trapped in the chest and lung collapse).

People presenting with hypotension of unknown cause, ultrasound has been utilized to determine the cause of shock. [10] [11] Evaluation of the heart and inferior vena cava (IVC) can help the clinician at the bedside choose important treatments and monitor the response to the interventions. [12] [13]

A person who has hypotension and a bedside ultrasound showing hyperdynamic left heart with a flat, collapsible IVC indicates low blood volume. If the person also has a fever, the clinician may determine sepsis, or severe infection is causing the problem. If that same hypotensive person has back pain instead of a fever, the clinician may see an abdominal aortic aneurysm that is leaking or ruptured. Conversely, weak heart activity and a very full, non-collapsible IVC would indicate a cardiac cause for low blood pressure.

For those presenting with acute shortness of breath, ultrasound assessment of the lung, heart, and IVC can evaluate for potentially life-threatening diseases, including pneumothorax, significant pleural effusions, congestive heart failure, pulmonary edema, pericardial effusion, and some large pulmonary emboli. [12] [14]

With its increased availability, ultrasound is now frequently used more in code situations, in which a person have lost most or all signs of life. [15] Practitioners may use the ultrasound to see if the heart is moving, beating in organized fashion or if it has a pericardial effusion or fluid around it. Pericardiocentesis, a procedure in which a needle is used to drain the effusion, can utilize ultrasound guidance of a needle to decrease the risk of hitting lungs, heart or other vital organs [16]

Monitoring therapy

Emergency ultrasound can not only diagnose, but also monitor a person's response to therapeutic interventions. Ultrasound can be utilized to assess a person's intravascular volume status and response to intravenous fluid therapy by measuring the size and respiratory change in the diameter of the IVC, [12] including the assessment of central venous collapsibility as a more standardized measure of intravascular volume status. [17] More recent evidence suggests that ultrasound assessment of more "peripheral" veins (e.g., subclavian, femoral, internal jugular) may also be helpful in estimating intravascular volume status in the absence of IVC visualization. [18] [19] Ultrasound of the lungs may demonstrate resolution of pulmonary edema from congestive heart failure. [20]

Procedural guidance

Using ultrasound to guide needles during procedures may improve success and decrease complications in procedures performed by multiple specialties, including central [21] and venous access, [22] [23] arterial cannulation, [24] thoracentesis, [25] paracentesis, pericardiocentesis, [26] arthrocentesis, regional anesthesia, incision and drainage of abscesses, [27] [28] localization and removal of foreign bodies, lumbar puncture, biopsies, and other procedures. [21]

Diagnostic

Point-of-care ultrasound is being increasingly used to speed patient care and to avoid ionizing radiation (for example, pediatric or pregnant patients). Quick diagnosis is still valuable for both an injured and healthcare professional. The efficiency of obtaining the answer to a focused question within minutes is one of the driving forces of the popularity of bedside ultrasound. Use of this modality in settings such as the emergency department can decrease waiting times and improve satisfaction among those served. [29]

Cardiac: Chest pain is one of the most common complaints presenting to the emergency department. Those presenting with chest pain, focused cardiac ultrasound can be helpful in the evaluation of persons with potentially life-threatening disease such as a pericardial effusion, a severe pulmonary embolus (or blood clot in the lungs), or in screening those with suspected aortic dissection. [12] The use of ultrasound is also helpful in persons with chest pain due to suspected heart ischemia, especially when the baseline electrocardiogram or EKG, is non-diagnostic. [12] The more technically demanding aspects of echocardiographic interpretation, and should be reserved for more formal comprehensive echocardiography. [12]

Abdominal complaints: Abdominal pain is also a common complaint in the primary care and emergency department setting. Gallbladder disease is a frequent cause of abdominal pain, but can also result in critical illness. Bedside ultrasound assesses the gallbladder for presence of gallstones that cause the majority of gallbladder illness. Emergency ultrasound of the gallbladder can help speed diagnosis and care. [30]

Flank pain can indicate obstructing kidney stones or abdominal aortic aneurysm. [31] If obstructing kidney stones are suspected, the kidneys can be evaluated by ultrasound for signs of obstruction, called hydronephrosis. [32] [33] A common use of ultrasound is identifying or evaluating the fetus in a person who is pregnant. Women in the first trimester of pregnancy can have a tubal or ectopic pregnancy outside the uterus that is life-threatening if not identified. [34] A more advanced fetus may be evaluated for normal heart rate and movement and gestational age to help guide care of both the fetus and the pregnant mother.

Other symptom-oriented diagnostic exams: Blood clots that form in deep veins of the body can break off and block blood vessels in the lungs, resulting in low oxygen, heart strain and death. The most common location of these deep vein thromboses (DVTs) is in the legs. A bedside ultrasound can determine the presence or absence of blood clots and their location in the proximal lower extremity to behind the knee. [35] [36] Those presenting with eye pain or visual loss, ultrasound of the eye can be used for the detection of orbital pathology. [37] Ultrasound has been described to detect retinal detachments, vitreous hemorrhage, dislocation of the lens, as well as evaluating optic nerve sheath diameters as a potential indicator of other diseases in the central nervous system. [38] [39]

Now that ultrasound is available in portable units that are smaller than laptop computers and handheld models, it is being used more and more in many clinical settings. Many practitioners use point-of-care ultrasound in diagnosing other urgent and emergency problems, including appendicitis, testicular torsion, and abscesses. To describe each of these fully is beyond the scope of this entry, and impossible as the use of ultrasound is expanding rapidly:

Training

Emergency and point-of-care ultrasound is taught in a variety of settings. Many physicians are currently taught bedside ultrasound during the emergency medicine residency or critical care fellowship training programs in the United States. It can also be learned as part of the continuing education process, through formal didactics, one-on-one training, training software, and clinical application and practice. Other specialists may learn during their residency or fellowship training programs. There are specialized fellowship training programs for bedside ultrasound in emergency medicine, but these are not required nor expected for the use of this tool in practice. Training has been expanded to other specialties in medical and surgical fields and is expected to expand in the future.

See also

Related Research Articles

<span class="mw-page-title-main">Appendicitis</span> Inflammation of the appendix

Appendicitis is inflammation of the appendix. Symptoms commonly include right lower abdominal pain, nausea, vomiting, and decreased appetite. However, approximately 40% of people do not have these typical symptoms. Severe complications of a ruptured appendix include widespread, painful inflammation of the inner lining of the abdominal wall and sepsis.

<span class="mw-page-title-main">Medical ultrasound</span> Diagnostic and therapeutic technique

Medical ultrasound includes diagnostic techniques using ultrasound, as well as therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal body structures such as tendons, muscles, joints, blood vessels, and internal organs, to measure some characteristics or to generate an informative audible sound. The usage of ultrasound to produce visual images for medicine is called medical ultrasonography or simply sonography, or echography. The practice of examining pregnant women using ultrasound is called obstetric ultrasonography, and was an early development of clinical ultrasonography. The machine used is called an ultrasound machine, a sonograph or an echograph. The visual image formed using this technique is called an ultrasonogram, a sonogram or an echogram.

<span class="mw-page-title-main">Cardiac tamponade</span> Buildup of fluid around the heart

Cardiac tamponade, also known as pericardial tamponade, is a compression of the heart due to pericardial effusion. Onset may be rapid or gradual. Symptoms typically include those of obstructive shock including shortness of breath, weakness, lightheadedness, and cough. Other symptoms may relate to the underlying cause.

<span class="mw-page-title-main">Cholecystitis</span> Inflammation of the gallbladder

Cholecystitis is inflammation of the gallbladder. Symptoms include right upper abdominal pain, pain in the right shoulder, nausea, vomiting, and occasionally fever. Often gallbladder attacks precede acute cholecystitis. The pain lasts longer in cholecystitis than in a typical gallbladder attack. Without appropriate treatment, recurrent episodes of cholecystitis are common. Complications of acute cholecystitis include gallstone pancreatitis, common bile duct stones, or inflammation of the common bile duct.

<span class="mw-page-title-main">Echocardiography</span> Medical imaging technique of the heart

Echocardiography, also known as cardiac ultrasound, is the use of ultrasound to examine the heart. It is a type of medical imaging, using standard ultrasound or Doppler ultrasound. The visual image formed using this technique is called an echocardiogram, a cardiac echo, or simply an echo.

<span class="mw-page-title-main">Pleural effusion</span> Accumulation of excess fluid in the pleural cavity

A pleural effusion is accumulation of excessive fluid in the pleural space, the potential space that surrounds each lung. Under normal conditions, pleural fluid is secreted by the parietal pleural capillaries at a rate of 0.6 millilitre per kilogram weight per hour, and is cleared by lymphatic absorption leaving behind only 5–15 millilitres of fluid, which helps to maintain a functional vacuum between the parietal and visceral pleurae. Excess fluid within the pleural space can impair inspiration by upsetting the functional vacuum and hydrostatically increasing the resistance against lung expansion, resulting in a fully or partially collapsed lung.

<span class="mw-page-title-main">Abdominal pain</span> Stomach aches

Abdominal pain, also known as a stomach ache, is a symptom associated with both non-serious and serious medical issues. Since the abdomen contains most of the body's vital organs, it can be an indicator of a wide variety of diseases. Given that, approaching the examination of a person and planning of a differential diagnosis is extremely important.

<span class="mw-page-title-main">Pericardiocentesis</span> Procedure where fluid is aspirated from the pericardium

Pericardiocentesis (PCC), also called pericardial tap, is a medical procedure where fluid is aspirated from the pericardium.

In medicine, Murphy's sign is a maneuver during a physical examination as part of the abdominal examination. It is useful for differentiating pain in the right upper quadrant. Typically, it is positive in cholecystitis, but negative in choledocholithiasis, pyelonephritis, and ascending cholangitis.

<span class="mw-page-title-main">Pericardial effusion</span> Medical condition

A pericardial effusion is an abnormal accumulation of fluid in the pericardial cavity. The pericardium is a two-part membrane surrounding the heart: the outer fibrous connective membrane and an inner two-layered serous membrane. The two layers of the serous membrane enclose the pericardial cavity between them. This pericardial space contains a small amount of pericardial fluid, normally 15-50 mL in volume. The pericardium, specifically the pericardial fluid provides lubrication, maintains the anatomic position of the heart in the chest, and also serves as a barrier to protect the heart from infection and inflammation in adjacent tissues and organs.

<span class="mw-page-title-main">Blunt trauma</span> Trauma to the body without penetration of the skin

Blunt trauma, also known as blunt force trauma or non-penetrating trauma, describes a physical trauma due to a forceful impact without penetration of the body's surface. Blunt trauma stands in contrast with penetrating trauma, which occurs when an object pierces the skin, enters body tissue, and creates an open wound. Blunt trauma occurs due to direct physical trauma or impactful force to a body part. Such incidents often occur with road traffic collisions, assaults, and sports-related injuries, and are notably common among the elderly who experience falls.

<span class="mw-page-title-main">Focused assessment with sonography for trauma</span> Fluid accumulation screening

Focused assessment with sonography in trauma is a rapid bedside ultrasound examination performed by surgeons, emergency physicians, and paramedics as a screening test for blood around the heart or abdominal organs (hemoperitoneum) after trauma. There is also the extended FAST (eFAST) which includes some additional ultrasound views to assess for pneumothorax.

<span class="mw-page-title-main">Abdominal ultrasonography</span> Type of medical scan

Abdominal ultrasonography is a form of medical ultrasonography to visualise abdominal anatomical structures. It uses transmission and reflection of ultrasound waves to visualise internal organs through the abdominal wall. For this reason, the procedure is also called a transabdominal ultrasound, in contrast to endoscopic ultrasound, the latter combining ultrasound with endoscopy through visualize internal structures from within hollow organs.

Obstructive shock is one of the four types of shock, caused by a physical obstruction in the flow of blood. Obstruction can occur at the level of the great vessels or the heart itself. Causes include pulmonary embolism, cardiac tamponade, and tension pneumothorax. These are all life-threatening. Symptoms may include shortness of breath, weakness, or altered mental status. Low blood pressure and tachycardia are often seen in shock. Other symptoms depend on the underlying cause.

<span class="mw-page-title-main">Electrocardiography in myocardial infarction</span>

Electrocardiography in suspected myocardial infarction has the main purpose of detecting ischemia or acute coronary injury in emergency department populations coming for symptoms of myocardial infarction (MI). Also, it can distinguish clinically different types of myocardial infarction.

Prehospital ultrasound is the specialized application of ultrasound by physicians and other emergency medical services (EMS) to guide immediate care and treatment procedures. Like conventional ultrasound, it is a device that produces cyclic sound pressure to penetrate a medium and reveal details about the inner structure of the medium.

A transmediastinal gunshot wound (TMGSW) is a penetrating injury to a person's thorax in which a bullet enters the mediastinum, possibly damaging some of the major structures in this area. Hemodynamic instability has been reported in about 50% of cases with a mortality rate ranging from 20% to 49%. Some studies have shown marked improvement in the mortality rate of patients who survived transfer to the operating room rather than being treated surgically in the ER.

Fracture sonography is the use of medical ultrasound to detect bone fractures. While medical ultrasound is used to visualize soft tissues like skin, organs, and blood vessels, fracture sonography is used to visualize fractures on only bone surfaces. It is useful for children aged 12 or younger because all fractures cause alterations of the bone surface, and joint fractures are uncommon at such ages. For joint fractures that are common in adult bones and cannot be visualized properly, patients older than 12 years are not eligible for ultrasound fracture diagnosis. The method is feasible for detecting fractures of the wrist, elbow, shoulder and clavicle. The advantages of fracture sonography are the avoidance of radiation exposure, faster examinations, and the ability to use standard ultrasound devices, which are more widespread. In the mentioned fields of application, ultrasound is as safe as X-ray diagnosis.

<span class="mw-page-title-main">Chest pain in children</span> Medical condition

Chest pain in children is the pain felt in the chest by infants, children and adolescents. In most cases the pain is not associated with the heart. It is primarily identified by the observance or report of pain by the infant, child or adolescent by reports of distress by parents or caregivers. Chest pain is not uncommon in children. Many children are seen in ambulatory clinics, emergency departments and hospitals and cardiology clinics. Most often there is a benign cause for the pain for most children. Some have conditions that are serious and possibly life-threatening. Chest pain in pediatric patients requires careful physical examination and a detailed history that would indicate the possibility of a serious cause. Studies of pediatric chest pain are sparse. It has been difficult to create evidence-based guidelines for evaluation.

<span class="mw-page-title-main">Spleen pain</span> Human pain from the area of the spleen

Spleen pain is a pain felt from the left upper quadrant of the abdomen or epigastrium where the human spleen is located or neighboring.

References

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  37. ↑ Blaivas M. Bedside emergency department ultrasongraphy in evaluation of ocular pathology. Acad Emerg Med. 2000; 7:947–950
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  39. ↑ Tayal V, Neulander M, Norton H, et al. Emergency department sonographic measurement of optic nerve sheath diameter to detect findings of increased intracranial pressure in adult head injury patients. Ann Emerg Med. 2007;49:508–514
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