Indications and instrument selection
In the surgeon's arsenal for this procedure, the primary instrument is the trocar. Structurally, it consists of two elements: a hollow tube called a cannula, and a sharp inner rod—the stylet—designed to pierce the tissues. Additionally, a Veress needle may be used to establish initial access.
Main clinical indications for the procedure:
- Fluid evacuation: removal of a pathological accumulation of transudate or exudate in ascites.
- Laparoscopy: creation of access for the insertion of optics and instruments for visual optical-instrumental examination of internal organs.
Patient preparation and positioning
Preparation for the procedure includes one absolutely critical requirement — mandatory preliminary emptying of the urinary bladder. Neglecting this rule causes the filled organ to significantly increase in size, rise high above the pubic bone, and incur an immense risk of accidental injury by the sharp stylet.
The patient's position during the procedure depends directly on the severity of their condition:
- The optimal and most convenient position for the physician is with the patient sitting.
- For severely ill patients who are physically unable to sit, performing the puncture in the lateral decubitus position is permissible.
Trocar insertion sites
The surgeon selects the puncture site to minimize the risk of vascular and internal structure trauma. In classical operative surgery, two main locations are used:
- Along the midline: the point is located strictly at the midpoint of the distance from the umbilical ring to the pubic symphysis.
- In the lateral region: the point is located slightly lateral to the midpoint of the imaginary line connecting the umbilicus and the anterior superior iliac spine (spina iliaca anterior superior) on the corresponding side.
Safe paracentesis technique in ascites
The procedure requires strict adherence to the protocol to prevent severe consequences.
- Prevention of fistula formation: Before making the puncture, the surgeon intentionally displaces the skin to the side. After completing the procedure and removing the instrument, the tissues return to their original position. Due to this technique, the wound tract within the soft tissues becomes tortuous, which reliably blocks the pathway for continuous fluid leakage.
- Instrument insertion: First, a small, neat skin incision is made using a scalpel. The trocar is inserted into the tissues through this opening. As soon as the instrument overcomes tissue resistance and enters the cavity, the inner stylet is removed, leaving only the hollow cannula.
- Evacuation: The accumulated fluid must be released exclusively slowly. At this critical moment, the physician continuously monitors the patient's vital signs — respiratory rate and pulse.
- Prevention of collapse: As a large volume of fluid is removed, intra-abdominal pressure begins to drop rapidly. To prevent a sharp pressure drop and hemodynamic collapse, the upper abdomen is tightly bound with a sterile sheet or towel.
Possible complications
Even with flawless technique and knowledge of topography, abdominal puncture carries a risk of complications.
First, there is bowel wall injury. This complication is particularly likely if the patient has pronounced adhesive disease, where the intestinal loops lose their natural mobility and become densely fixed to the tissues of the abdominal wall.
Second, ascitic fistula formation is possible. This issue occurs if the surgeon forgets to displace the skin prior to puncture, leaving a straight wound tract through which fluid continues to ooze outward.
Briefly: answers to topical questions
What complications may occur during abdominal puncture?
Complications of abdominal puncture include:
- bowel injury in the presence of adhesions;
- ascitic fistula formation;
- local subcutaneous hematomas;
- collapse due to a sharp drop in intra-abdominal pressure;
- hepatorenal syndrome following large-volume paracentesis without human albumin administration;
- infection of ascitic fluid and soft tissues during the placement of permanent peritoneal drains.
What is the maximum volume of fluid that can be safely evacuated in a single paracentesis procedure?
The maximum possible amount of fluid should be drained during a single paracentesis procedure. Evacuation is performed continuously over 1–4 hours. At the same time, an appropriate amount of human albumin must be administered; its dose should not exceed 100 g/day. High-volume paracentesis without human albumin administration is a triggering factor for hepatorenal syndrome.
To easily remember the puncture sites, imagine an inverted "V" originating from the umbilicus: one line goes straight down to the pubic bone (puncture right in the middle), and the second goes laterally toward the spina iliaca (puncture slightly lateral to its midpoint).
Class and exam questions
Why displace the skin before introducing the trocar?
This is necessary to create a tortuous wound tract in the soft tissues. This surgical technique serves as the main prevention of ascites fistula formation after instrument removal.
Why must fluid in ascites be released slowly?
Rapid removal of a large volume of fluid leads to a sharp drop in intra-abdominal pressure. This can trigger blood redistribution, a drop in blood pressure, and severe collapse.
What mandatory action must be performed before starting the puncture?
The patient must empty their urinary bladder. A full bladder extends beyond the lesser pelvis and may be accidentally punctured by the trocar during the procedure.
In what case is the risk of bowel injury high during paracentesis?
Bowel wall injury is most likely in the presence of adhesions in the abdominal cavity. Under such conditions, intestinal loops lose mobility and adhere to the abdominal wall.
What else to study on this topic
- Design and types of surgical trocars
- Topographic anatomy of the anterior abdominal wall at the puncture sites
- Hemodynamic changes during a sharp decrease in intra-abdominal pressure
- Abdominal adhesive disease: causes and impact on surgical approaches
- Features of optical-instrumental examination (laparoscopy)
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