Diagnostic Aspiration of Ascites
- Confirm the indications for aspiration of ascites. Explain the procedure to the patient and obtain consent. Deranged clotting (common in patients with cirrhosis and ascites) is not a contraindication, but ask advice from a haematologist if the patient has disseminated intravascular coagulation (p. 581). Complications of the procedure (haematoma, haemoperitoneum, infection) are rare. Inadvertent puncture of the intestine may occur but rarely leads to secondary infection.
- The patient should lie relaxed in a supine position, having emptied the bladder. With guidance by ultrasonography, select a site for puncture in the right or left lower quadrant, away from scars and the inferior epigastric artery (whose surface marking is a line drawn from the femoral pulse to the umbilicus).
- Put on gloves. Prepare the skin with chlorhexidine. Anaesthetize the skin with 2 mL of lidocaine 1% using a 25 G (orange) needle. Then infiltrate a further 5 mL of lidocaine along the planned needle path through the abdominal wall and down to the peritoneum.
- Give the local anaesthetic time to work. Mount a 21 G (green) needle on a 50 mL syringe and then advance along the anaesthetized path. Aspirate as you advance. Having entered the peritoneal cavity, aspirate 30–50 mL of ascites. Remove the needle and place a small dressing over the puncture site.
- Send samples for:
- Albumin concentration (plain tube), if the aetiology is unknown
- Total and differential white cell count (EDTA tube)
- Bacterial culture (inoculate aerobic and anaerobic blood culture bottles with 10 mL each)
- Other tests if indicated (Table 24.1)
- Clear up and dispose of sharps safely. Write a note of the procedure in the patient's record: findings on ultrasonography/approach/appearance of ascites/volume aspirated/samples sent. Ensure the samples are sent promptly for analysis.