Wounds are a symptom of disease, and usually the first disease we have to rule out in patients with lower extremity wounds is poor perfusion. Arterial disease is the most common reason, but not the only one. I rely on skin perfusion pressure (SPP) to determine whether the perfusion specifically to the area of the wound is adequate. I am going to post a series of articles explaining why I must have this machine or I can’t provide adequate care.
Because Arterial Doppler just isn’t good enough
This is an 80-year-old woman and at the time the picture above was taken, she’d had a nonhealing right anterior shin ulcer for 4 months. It began as a scratch, and clinically it’s suspicious for pyoderma gangrenosum (which is what she turned out to have). However, she’s also got ischemic rest pain. It hurts to elevate her leg, and she’s sleeping in a chair due to leg pain. PG is definitely painful, but it doesn’t cause rest pain. To make matters worse, she was placed in an Unna’s boot for her edema (caused in part by chair sleeping) and compression caused excruciating pain. Two cardiologists referred her for venous ablation because her arterial Dopplers suggested she did not have significant arterial disease.
On her first visit, I performed arterial screening with skin perfusion pressure and the SPP on the right foot was only 33 mmHg with a dampened pulse volume recording (PVR). In comparison, the SPP on the left was 95 mmHg with a normal PVR. That’s a very big difference between the left and the right legs, and an SPP around 30 suggests significant arterial disease. I referred her to Dr. David Kuten, who found a nearly 100% occlusion of her anterior tibial artery, which he was able to open.
We are still struggling with her pyoderma, but at least now she can be safely treated with compression. (And folks, this is not what a venous ulcer looks like, even if she does have venous insufficiency.)
What do we learn from this?
- Arterial Dopplers are not a good way to find isolated below the knee disease.
- Listen to the patient’s history
- Just because a patient has venous insufficiency does not mean their ulcer is venous
- SPP is superior to Arterial Doppler to assess the perfusion of a wound
I need SPP to do my job. Stay tuned for more