Ascites

Abdominal drains are part of our syllabus, but in practice they are normally not done in the ED.

Anatomy
The needle should not insert the rectus abdominus muscle, which is either side of the midline. This can cause epigastric bleeding. Aim for about 15cm lateral to the umbilicus.
Use the Z technique - pierce the skin, pull the skin tight, then aspirate.
The needle pierces:
    Skin
    Subcutaneous fat
    Superficial fascia
    External oblique muscle
    Internal oblique muscle
    Transversalis muscle
    Parietal peritoneum.

Contraindications
Patient refusal or distress
Pregnancy
Abdominal obstruction or distended bowel loops
Cellulitis overlying the puncture site
Severe coagulopathy

Complications
Abdominal Haematoma (1 in 100 patients)
Severe bleeding (haemoperitoneum)
Infection (secondary bacterial peritonitis)
Bowel perforation/organ damage
Persistent site leakage
Hypovolaemia or hypotension
Recurrence (highly likely unless followed up with diuretic therapy)

Causes of Ascites
High SAAG (“transudate”)
cirrhosis, hepatic failure, hepatic venous occlusion, constrictive percarditis, kwashiorkor, cardiac failure, alcoholic hepatitis, liver metastasis

Low SSAG (“exudate”)
malignancy, infection (bacterial, fungal, Tb), pancreatitis, nephrotic syndrome, bowel obstruction or infarction, bile leak

References
http://www.healthline.com/health/z-track-injection#what-are-z-track-injections1
https://lifeinthefastlane.com/ccc/ascitic-fluid/
https://lifeinthefastlane.com/procedures/paracentesis/
http://learning.bmj.com/learning/modules/end/JIT.html?moduleId=10033853&resType=&resTypeId=&locale=en_GB&presourceId=0&site=