View source for EBQ:Quantitative sensitivity of ultrasound in detecting free intraperitoneal fluid

{{JC info
| title= Sonographic Estimation of the Volume of Free Intraperitoneal Fluid
| abbreviation= 
| expansion= 
| published= 1994
| author= Goldberg BB, Goodman GA, Clearfield HR.
| journal= J Ultrasound Med
| year= 1994
| volume= 13
| issue= 12
| pages= 915-920
| pmid= 7674411
| fulltexturl= 
| pdfurl= 
| status = Complete
}}

==Clinical Question==
What is the minimum volume of free intraperitoneal fluid that can be reliably detected by abdominal ultrasound?

==Conclusion==
*Ultrasound can detect as little as 100-200 mL of free intraperitoneal fluid in optimal conditions
*The sensitivity of ultrasound for free fluid detection increases with larger fluid volumes
*FAST examination has limitations in detecting small volumes of intraperitoneal fluid

==Major Points==
*This study helped define the quantitative threshold for ultrasound detection of free fluid
*In the supine position, fluid first accumulates in the hepatorenal recess (Morrison pouch) and pelvis
*Detection sensitivity is operator-dependent and varies with patient body habitus
*The study provided evidence for understanding the limitations of FAST in trauma
*Small-volume hemoperitoneum (<200 mL) may be missed on initial FAST examination, supporting the role of serial examinations or CT

==Study Design==
*Prospective observational study
*Controlled infusion of known volumes of fluid into the peritoneal cavity
*Ultrasound examinations performed at incremental fluid volumes
*Primary Outcome: minimum detectable volume of intraperitoneal fluid by ultrasound

==Population==
*Patients undergoing peritoneal dialysis or paracentesis with known intraperitoneal fluid volumes

==Interventions==
*Controlled instillation of intraperitoneal fluid (peritoneal dialysis patients)
*Ultrasound examination at standard FAST positions (Morrison pouch, splenorenal recess, pelvis)
*Correlation of ultrasound findings with known fluid volumes

==Outcomes==
===Primary Outcome===
*Minimum detectable free fluid volume: approximately 100-200 mL in optimal conditions
*Detection rate increased progressively with larger volumes
===Secondary Outcomes===
*Morrison pouch was the most sensitive location for detecting small volumes of free fluid in the supine position
*Pelvic views were most sensitive for very small fluid collections
*Sensitivity approached 100% at volumes >500 mL

==Criticisms==
*Study used controlled fluid volumes in non-trauma patients, which may not reflect the variable distribution of blood in trauma
*Blood has different echogenic properties than dialysate or ascitic fluid
*Body habitus, bowel gas, and patient positioning significantly affect detection sensitivity
*The study predates modern FAST protocols and high-frequency transducers
*Does not account for clotted blood, which may be more difficult to detect than free fluid

==Funding==
*None reported

==See Also==
*[[FAST exam]]
*[[Abdominal trauma]]
*[[Hemoperitoneum]]

==References==
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[[Category:EBQ]]
[[Category:Trauma]]
[[Category:Ultrasound]]