From the Guidelines
Fluid collections after surgical incisions and subcutaneous emphysema on CT scans are common postoperative findings that require monitoring but often resolve on their own, and the most recent guidelines suggest that routine placement of a subcutaneous drain during the closure of abdominal wall incision does not confer any advantage in preventing postoperative wound infection 1. The presence of fluid collections and subcutaneous emphysema on CT scans should be interpreted in the context of the patient's clinical condition, including vital signs, pain levels, and wound appearance. Some key points to consider include:
- Fluid collections typically represent seromas (clear fluid) or hematomas (blood collections) that develop in the surgical site as part of the normal healing process.
- Subcutaneous emphysema refers to air trapped in the tissue beneath the skin, which appears as dark streaks or bubbles on CT imaging.
- Most small fluid collections and mild subcutaneous emphysema resolve spontaneously within 1-2 weeks without intervention.
- Large fluid collections may require drainage if they cause significant pain, pressure, or show signs of infection (redness, warmth, increasing pain).
- Extensive subcutaneous emphysema should be monitored closely, especially if it causes breathing difficulties or severe discomfort. The underlying mechanism involves disruption of tissue planes during surgery, allowing fluid or air to accumulate in potential spaces created during the procedure, as discussed in the guidelines for the diagnosis and management of skin and soft-tissue infections 1. In terms of management, the American College of Radiology Appropriateness Criteria suggest that minimally invasive image-guided management strategies for infected fluid collections are often preferred over more invasive options, given their low rate of complications and high rates of success 1. However, the decision to intervene should be based on the patient's clinical condition and the presence of signs of infection or other complications, rather than the presence of fluid collections or subcutaneous emphysema alone, as recommended by the World Society of Emergency Surgery guidelines for the closure of laparotomy in emergency settings 1.
From the Research
Fluid Collections Post Surgical Incision
- Fluid collections post surgical incision can be a major problem associated with open abdominal surgery, leading to increased morbidity and mortality rates, healthcare costs, and incisional hernia 2.
- The use of negative pressure subcutaneous drains can reduce dead space in subcutaneous tissue by preventing accumulation of fluid, which may help prevent surgical site infection (SSI) 2.
Subcutaneous Emphysema on CT
- Subcutaneous emphysema is a common finding in emergency department imaging studies, and it can be associated with traumatic, iatrogenic, or infectious causes 3.
- CT scans can confirm the presence of subcutaneous emphysema and reveal other related conditions such as mediastinal emphysema and pneumothorax 4, 3, 5.
- Subcutaneous emphysema can be a diagnostic clue in the emergency room, and radiologists must be aware of abnormal gas in soft tissue as it may be the main or unique sign leading to an underlying pathology 3.
Management of Fluid Collections and Subcutaneous Emphysema
- Percutaneous radiologic drainage is considered the first-line treatment of infected post-operative collections and is successful in over 80% of patients 6.
- Cooperation between the surgeon and the interventional radiologist is essential to optimize the management of post-operative complications, including fluid collections and subcutaneous emphysema 6.
- In cases of severe anaerobic infection inducing mediastinal and subcutaneous emphysema, septic shock, and ARDS, VV-ECMO and NGS-guided therapy may be effective management strategies 5.