Emergency Medical Technician (EMT) Basic Certification Practice Exam

Which sign might indicate hypoxia in an extremity affected by compartment syndrome?

1. Pulses may be absent

2. Extremity may feel hard

3. Skin may appear normal

4. Movement increases

The correct answer is: Extremity may feel hard

In the context of compartment syndrome, the sign indicating hypoxia in the affected extremity involves the extremity feeling hard. Compartment syndrome occurs when increased pressure within a closed muscle compartment compromises circulation and function of the tissues within that space. As pressure builds, it can impede blood flow, leading to ischemia and hypoxia in the muscles and nerves. When pressure rises, the affected compartment may become firm or hard to the touch due to swelling and the accumulation of fluid within the fascial layers that enclose muscles. This rigidity is a direct consequence of the swelling in a confined space and can be a significant clinical finding that suggests tissue ischemia, potentially leading to irreversible muscle and nerve damage if not recognized and treated promptly. In contrast, while absent pulses may suggest severe hypoxia or compromised blood flow, the earliest and most characteristic finding in compartment syndrome is the firmness of the affected compartment. The appearance of the skin may still seem normal in early stages, as symptoms can evolve, and increased movement typically leads to more pain and does not indicate hypoxia directly.