More than meets the “I”
There is a small amount of pleural effusion (blue arrow). The IVC is almost collapsed (yellow arrow), or kissing each other, in end inspiration. This could be due to low right atrial pressure and hypovolemia, or dyspnea in patient with vigorous inspiratory effort, or both (as in this case). There is something very bright, however, within the substance of the liver (red arrow).
Take a look at the scan in real-time:
The bright thing is AIR, i.e. the patient has aerobilia. As mentioned in the earlier post, soft tissue-air interface is bright. The air here is coalescent and linear, as it's within the bile ducts. More importantly, one can also appreciate its movement within the biliary tree. In fact, this biliary air has also entered into the patient’s gallbladder, as shown below:
Rapid sequence intubation was performed soon after the scan and aggressive resuscitation continued. The abdominal assessment was completed using the S.A.F.E.R approach: the stomach found to be full of fluid with echogenic material. We inserted an NG tube, and that drained 1L of altered blood. Massive transfusion protocol was activated.
Post resuscitation, the patient’s vital signs improved. The repeat IVC is as shown:
Notice that the IVC is now distended. IVC becomes bigger due to positive pressure ventilation alone. But since it distends by less than 18% (you can also tell this by eyeballing), we know that the patient is unlikely to be fluid responsive at this point in time. He was covered with broad-spectrum antibiotics and PPI.
The surgeons took over this care: the patient had a contained perforated duodenal ulcer with choledochoduodenal fistula, He recovered from this episode and was eventually discharged home.
Staying focus in POCUS is essential; but that does not mean turning a blind eye to the rest of the image. As you have seen, it could be more than meets the eye.
IVC ultrasound is a great tool; but never interpret it alone. Always integrate it with the other sonographic findings (esp heart and lung) + integrate it in the clinical context.
Air in the abdomen, like fluid, can be free (intraperitoneal) or "trapped" (intraparenchymal, intramural, intraductal, intraluminal). Learn to recognize them in real-time, as they can clue you to the patient's problem.
Wui K. Chong (2014). Abdominal Ultrasound, an issue of Ultrasound Clinics. Elsevier.
Dr. Toh Hong Chuen
Acute and Emergency Care Centre, Khoo Teck Puat Hospital. Singapore