Dr. O. John Ma was one of the pioneers for developing ultrasound for trauma, starting in 1992. He reflects on the evolution of ultrasound for abdominal trauma in the emergency department now in its fourth decade.
Disorders ranging from benign, self-limiting conditions to processes demanding emergency surgery can present with acute pain of the abdomen and pelvis. Abdominal trauma accounts for up to 20% of all trauma deaths. Massive hemorrhage may result in death soon after injury. Patients who survive the initial traumatic insult become at risk for infection and sepsis.
In treating abdominal injuries, time is of the essence. The technologies available to emergency physicians have evolved over the last four decades to provide faster, more accurate diagnosis with greatly lowered risk of iatrogenic injury. Point-of-care ultrasound, Dr. O. John Ma points out, has come to play a central role in the diagnosis and treatment of abdominal trauma in the ER.
Ultrasound has emerged as the diagnostic tool of choice for evaluation of pediatric and pregnant patients with acute abdominal pain. It has demonstrated robust utility for the evaluation of suspected obstetric and gynecologic disorders, for right upper quadrant pain, and especially for rapid identification of free intraperitoneal fluid in the hypotensive patient with blunt abdominal trauma. Dr. O. John Ma points out.
In the FAST (Focused Assessment with Sonography for Trauma) protocol, ultrasound examination is rapid, noninvasive, portable, and repeatable, Dr. O. John Ma says. It is free from ionizing radiation. Quick detection of massive hemoperitoneum is accomplished with a single view of Morison’s pouch. FAST facilitates the detection of pleural or peritoneal fluids and can be used to detect pneumothorax.
A disadvantage of FAST is that interpretation is more operator-dependent than CT. FAST is not as useful as CT in examination of patients who have excessive bowel gas, who are obese, or who have subcutaneous air. FAST and CT are therefore complementary rather than competing technologies.
But the benefits of FAST extend beyond diagnosis. FAST ultrasound can be clinically useful in resuscitation. Ultrasound-guided placement of large-bore peripheral lines, and central venous catheters enhances volume resuscitation. FAST can be used to monitor the status of free intraperitoneal fluid. The FAST exam has essentially replaced diagnostic peritoneal lavage.
The FAST examination was originally developed as a limited ultrasound examination. It was primarily focused on the detection of free fluid. It was not designed to identify all sonographically detectable pathology in every patient. Over the last decade many groups have proposed additions or modifications to the standard FAST examination, the most popular of which is the Extended FAST (E-FAST) examination. With the development of FAST, ultrasound has become invaluable in the assessment of patients with:
– Presence of abdominal pain, tenderness, distention, or external signs of trauma
– Mechanism of injury with a high likelihood of causing an abdominal injury
– Suspicious chest, back, or pelvic injury
– Presence of distracting injuries
– Altered consciousness/sensorium (e.g., CNS injury, intoxicating substances)
Ultrasound, Dr. O. John Ma says, ensures that patients get the care they need when they need it.