Compartment syndrome can be identified through neurovascular assessment in patients following extreme trauma. It tests blood flow to the extremity, distal to the injury, and nerve function. Most neurovascular problems will appear in patients who have suffered a crush injury, or when a cast or splint has been used to stabilise a fracture.
Limb muscles are contained in a fibrous sheath known as a compartment. If blood leaks in to the compartment, or the compartment is compressed, it can cause a decrease in neurovascular integrity, distal to the compressing agent or injury. This is known as compartment syndrome.
When assessing for neurovascular integrity, remember the five Ps: pallor, pain, pulse, paralysis and paraesthesia.
Pallor is a good indicator of whether the extremity is being perfused, distal to the cast or injury. The skin of the hand or foot should be warm, pink, and free of swelling. A dusky or ashy appearance indicates the onset of compartment syndrome. Place the back of your hand against the hand or foot and check for temperature. The skin should be warm, not cold, and swelling may be present if the blood return is not able to exit the hand. Assess whether blood is getting to the extremity or if it is able to drain. Check for capillary refill and note if it is sluggish or absent. If not, the possibility of compartment syndrome increases.
Pain is the most important indicator of impending compartment syndrome and has its own pattern to distinguish it from other types of pain (such as post-operative pain). It is diffuse and progressive, sometimes difficult to pinpoint for both the patient and the nurse. Analgesia usually doesn’t work as effectively to relieve it. One way to assess this type of pain is passive flexion of the extremity. For instance with a foot injury, the nurse would extend the toe toward the knee and back. Any painful response should be reported as possibly compartment syndrome.
Pulses in the extremity will tell you if the arterial bed is intact. With crush injuries, the arteries may be compromised and unable to deliver blood to the hand or foot. When you are dealing with hand injuries, you want to check the radial pulse. If it is distal to the injury, you may check a brachial pulse as well, but this is usually covered with the cast, or not distal. When checking the foot for possible compartment syndrome, you should check the dorsalis pedis and posterior tibial arteries. If you are unable to find them, you may want to try sonographic assessment. A weak or absent pulse means that blood is not getting to the tissue and needs to be reported before the hand or foot become necrotic. Swift intervention is critical when encountering changes in pulse.
If the nerves distal to the extremity are injured or pressed upon by impending compartment syndrome, the patient will not be able to move the toes or fingers. Inability to dorsiflex and plantar flex their toes should be noted, as well as any weakness experienced. These movements may cause the patient pain, but the purpose of this assessment is to find if the patient still retains movement in the extremity. Similarly, arm injuries would require flexion and extension of the wrist and fingers.
Testing for paresthesia essentially means testing for sensation. The patient may not have full absence of sensation except in worsening cases of compartment syndrome. Assess paresthesia by varying pressure on extremities using a light touch and possibly pricking the toe or thumb with the end of a pen cap. A pins and needles feeling in the extremity is a sign of a sensation issue. If the nerves are impinged by increasing pressure, the patient may describe their foot or hand as “falling asleep.” This is another early sign that should be noted and reported.