There is much debate about whether it is safe to drain large volumes of fluid rapidly from the abdomen. One concern is that profound hypotension may follow because of the sudden release of intra‐abdominal pressure and consequent possible vasodilation (Lee et al. [139]). However, it is suggested that up to 5 litres of fluid may be safely drained over a few hours and it is not necessary to drain the abdomen until dry (Pericleous et al. [227], Stephenson and Gilbert [277]). In cases of cirrhosis, however, Moore and Aithal ([187]) suggest that all fluid should be drained to dryness in a single session as rapidly as possible over 1–4 hours, assisted by gentle mobilization of the cannula or turning the patient on their side if needed.

It is generally not necessary to have intravenous fluid or albumin replacement. However, patients with ascites who have large tumours, cirrhosis of the liver or renal impairment may require slower drainage of fluid and possible fluid replacement, depending on their clinical condition. Abdominal and peritoneal tumours can cause ascites to develop independently of the circulatory system and therefore hypotension is not usually seen as the ascites is drained.

A small study has shown that the success of blind paracentesis is directly related to the amount of fluid present (44% with 300 mL and 78% with 500 mL) (McGibbon et al. [175]). The literature suggests the use of ultrasound‐guided paracentesis to confirm the presence of ascites and also to identify the best site to perform paracentesis, particularly when a small amount of fluid is present (McGibbon et al. [175]).

The patient's clinical condition and purpose of the procedure must be taken into account when deciding what investigations are necessary but pre‐procedure investigations usually include a blood screen and ultrasound examination. To keep intrusion to a minimum for palliative patients, fewer investigations may be performed. Blood is usually checked for FBC, U&Es, creatinine, LFTs, plasma proteins and coagulation screen (Rull [257]). In the case of a diagnostic paracentesis, the ascitic fluid should be analysed for cell count, bacterial culture, total protein and albumin (Hou and Sanyal [113]).

Interventions used to treat ascites range from an aggressive approach to a purely palliative approach. There have been few definitive studies that have evaluated the different approaches in the treatment of malignant ascites (Hosttetter et al. [112]). While paracentesis is effective, ascites recurs, requiring repeated procedures. This imposes a further burden on patients and their families (Mercadante et al. [178]). Methods for treating ascites may include the use of diuretics, paracentesis and a diet low in sodium, instillation of peritoneal agents or the insertion of long‐term catheters (Ayantunde and Parsons [10]).

In terms of the use of drains, there is no consensus in the literature in relation to how long the drain should stay in place, whether the volume of fluid drained should be replaced intravenously, whether the drain should be clamped to regulate the drainage of fluid and whether any vital observations should be regularly recorded (Keen et al. [132]). However, many UK guidelines (London Cancer Alliance [151]) suggest that the ascites can be left to drain freely; clamping of the tube is not necessary unless the patient becomes hypotensive, in which case the drain is clamped for 20 minutes. The blood pressure should then be checked before further drainage.

In practice, most local guidelines suggest draining 1 litre, then clamping before checking the blood pressure. If the patient is not hypotensive (systolic  <  90) then drainage can continue and this process should be repeated after every litre drained. There is no evidence that albumin support is beneficial and intravenous fluids are only used if the patient becomes hypotensive despite clamping the drain (Moore and Aithal [187]). The evidence suggests that drainage limited to 5–8 litres provides the greatest symptomatic relief and a reduction in potential complications. This evidence makes day case paracentesis a preferred option for many patients (Becker et al. [13]).

In chronic management, ascites frequently reaccumulates and drainage tends to provide ever‐decreasing symptomatic benefit, but it is still worth performing. With recurrent drainage, there is an increasing risk that the ascites can become loculated, therefore a more permanent drain such as a PleurX™ may be appropriate (NICE [210]). Types of catheters are discussed further under ‘Equipment’.

Common interventions in ascites include:

It should however be noted that the literature available is mostly generated from studies in patients suffering from acute or chronic liver failure; this should be taken into account when managing patients with non‐malignant ascites.

Nursing and medical care of patients with malignant abdominal ascites should be aimed at improving quality of life by relieving suffering caused by the symptoms (Cope [46]). Each patient should be carefully assessed with consideration of their individual circumstances, maintaining respect for their wish to have or not to have interventional treatment (Campbell [28]).

For many patients accumulation of ascitic fluid is a poor prognostic indicator and therefore the management is palliative (Ayantunde and Parsons [10]).

The procedure is performed by a doctor or a practitioner trained in paracentesis assisted by a nurse or healthcare professional throughout. There is no accredited pathway or course for learning this clinical skill and specific training has to be negotiated and developed locally (Vaughan [298]).

Three types of long‐term catheter are generally used:

Nurses should describe the equipment to be used during paracentesis to the patient. This may be more relevant when looking after a patient undergoing the procedure for the first time to whom the size of the catheter may be concerning.

A detailed and consistent nursing assessment is important when caring for patients requiring paracentesis. Nurses should pay attention to the cause of the ascites and the frequency with which the procedure is occurring. The involvement of the palliative care team may be indicated at this stage. In cases of ascites secondary to cirrhosis, nurses should pay special attention to unresolved issues surrounding alcohol abuse, offering support and information to the patient and family. As well as assessing the patient's psychological well‐being, nurses must pay attention to the skin condition and pain levels.

In preparation for the paracentesis, the following investigations should take place to ensure patient safety: a full set of observations and baseline blood tests (FBC, U&Es and clotting). It is recommended that platelets are >  50  ×  10⁹/L and international normalized ratio (INR) 5 L/24 hours (NICE 2012d). However, an abnormal INR or thrombocytopenia is not a contraindication to paracentesis, and in most patients there is no need to transfuse fresh frozen plasma or platelets prior to the procedure (Runyon [258]). Of patients with ascites, 70% have an abnormal prothrombin time, but the actual risk of bleeding following paracentesis is very low (less than 1% of patients require transfusion). Exceptions are patients with clinically apparent disseminated intravascular coagulation or clinically apparent hyperfibrinolysis, who require treatment to decrease their risk of bleeding before undergoing paracentesis (McVay and Toy [177]). The patient's girth around the umbilicus should be measured and weight checked before the procedure; this should be clearly documented to allow for subsequent comparisons to be made. There is no need for the patient to fast prior to this procedure.

The healthcare professional performing the paracentesis must use a local anaesthetic (e.g. lidocaine 1%). The lidocaine is injected subcutaneously initially with a 25 G needle and subsequently with a 23 G needle until optimal pain control is achieved, not exceeding the maximum dose of 4.5 mg/kg (or 200 mg). Optimal pain control is achieved between 2 and 5 minutes after the drug is injected and it is important for the practitioner to assess the effectiveness of the local anaesthetic before the insertion of the catheter and drainage of ascites. Lorazepam at a dose of 1 mg can be of benefit prior to the procedure for patients who are anxious, due to its muscle relaxant and anxiolytic effects (Joint Formulary Committee [122]).

The nurse should enquire about the patient's fears and concerns regarding paracentesis. For some patients, music or relaxation, physical relaxation and visualization techniques are of great benefit so use of these approaches should be considered, if available (Misra [184]).