Superficial stab wounds: How do we know they’re superficial?

Resident Clinical Pearl – October 2016

Kyle McGivery, PGY3 iFMEM, Dalhousie University, Saint John, New Brunswick

Case 1:

A 22 year old male presents with three stab wounds to his right anterior chest following an altercation. He is alert, sitting the stretcher texting, and is hemodynamically stable. How should this patient be managed? When can he be safely discharged?

POCUS: Bedside cardiac and eFAST exams should be performed immediately to r/o pericardial effusion, pneumothorax, and free fluid. If the ultrasound is positive, arrange urgent surgical consult. If negative, proceed with chest xray.

Wound probing: Careful wound probing with Q-tip/sterile glove may help characterize the depth and possible intrathoracic extension of the wound. Wound probing cannot definitively rule out penetration into thoracic cavity. Consensus on performing this procedure is lacking, some consider there is a risk of causing a pneumothorax, although this seems unlikely if done carefully.

Monitoring and follow up imaging: In a patient with no intrathoracic injury who remains asymptomatic, a repeat chest X-ray should be performed. Previously a 6-hour follow up X-ray was preferred. More recent literature suggests that shortening this period to 3 hours has no effect on outcomes. In either case, 1-3% of patients will have clinically important findings on repeat chest X-ray. Additionally, Berg, RJ et al. found that a 1 hour repeat X-ray did not result in fewer significant findings as compared to a 3 hour interval.

Figure 1. Anterior abdominal stab wounds

Case 2:

A 24 year old male from the same altercation presents with the following injuries: see Figure 1

He has stable vitals, a normal DRE, and no sign of peritoneal irritation. How should this patient with abdominal stab wounds be managed?

Indications for immediate surgical intervention:

Hemodynamic instability
Peritonitis
Impalement
Evisceration
Frank blood from NG or DRE

For patients not meeting the above criteria, there are several options for management.

POCUS: All patients with abdominal penetrating injury should have a eFAST exam performed urgently. A positive fast requires surgical consultation. Diagnostic peritoneal lavage may be considered but is no longer considered as part of the routine work up.

Local wound exploration (LWE): Under sterile conditions, the wound can be inspected and possibly extended to determine if fascia has been breached. Peritoneal violation occurs in 50-70% of abdominal stab wounds and half of these require surgical interventions. If the fascia is intact, intra-abdominal injury is unlikely and discharge may be considered. In order to be reliable, fascia must be visualized. When performed by trained staff, LWE is 100% sensitive; it will allow for discharge in 25% of patients with abdominal stab wounds.

Figure 2. Local wound exploration demonstrating the anterior abdominal fascia breach

Imaging: A plain film xray may reveal free air or impaled objects though a normal film does not rule out intra-abdominal injury. The CT scan has an estimated sensitivity of 97% and specificity of 98% for identifying peritoneal violation. While routine CT is not mandatory, it should be strongly considered for upper quadrant injuries to assess for solid organ injury. A normal CT should not preclude further work up or observation.

Observation: Stable patients who have not had LWE should be observed for a minimum of 12 hours with serial physical exams +/- serial imaging and labs. Surgical consultation should be considered in the event of tachycardia, hypotension, leukocytosis, or worsening pain.

Key Points:

All patients with superficial stab wounds to the chest require ultrasound to rule out pericardial effusion.
Repeat chest X-ray at 1-3 hours is appropriate for stable chest stab wounds; 1-3% of these will have new clinically significant findings.
CT scan is not 100% sensitive for evaluating intraperitoneal stab wounds; patients therefore require local wound exploration or observation for a minimum of 12 hours before discharge.

References:

https://www.emrap.org/episode/julyemrap/traumasurgeons

http://lifeinthefastlane.com/trauma-tribulation-02/

www.uptodate.com

http://emedicine.medscape.com/article/82869-overview?src=refgatesrc1

Berg RJ1, Inaba K, Recinos G, Barmparas G, Teixeira PG, Georgiou C, Shatz D, Rhee P, Demetriades D. Prospective evaluation of early follow-up chest radiography after penetrating thoracic injury. (2013). Prospective evaluation of early follow-up chest radiography after penetrating thoracic injury., 37(6), 1286–1290. http://doi.org/10.1007/s00268-013-2002-0