Clinical examination - arterial ulcers
In Figure 1 we have provided you with an easy to follow protocol for performing a standardized examination of a patient with arterial ulcers. Yes, it is a bit time consuming but doing the examination in a standardized manner ensures that you will not forget to ask/check for important things along the way. Click on the image below and it will open a pdf which you can print out and use in your clinic. This is your baseline and can follow the patient’s chart during the entire treatment. At following visits, you obviously will not need to go through the whole protocol again. Note that the examination of the ulcer/wound is at the end of the protocol. You need to find out a lot about the patient before you jump to the inspection of the ulcer. Remember- do not just look at the hole in the patient, look at the whole patient! The evaluation of the wound follows the international TIMES model for wound assessment. For more information on the TIMES acronym we have written a separate chapter on this.
Figure 1 A standardized protocol for the examination of patients with arterial ulcers. Click on the image above to go to a two-page pdf file which you can print out for use in your clinic.
If the patient with an ulcer on the leg or foot complains of pain in the legs when walking or even pain while resting you should have a high suspicion og ischemia. Pain while resting indicates advanced artherosclerosis. Always keep in mind that patients with diabetic neuropathy may not feel any pain at all even at advanced stages of atherosclerosis! Again, always check new patients who have arterial ulcers for diabetes! We have ourselves gone into the trap of not checking this many times! The worst situation is an arterial ulcer combined with a blood sugar that is out of control. Remember that diabetes is one of the most common factors leading to atherosclerosis and subsequent inadequate circulation.
Before you start looking at the lower extremities and the ulcer itself you should do a quick patient history. The essential parts of the patient history are summarized in the suggested protocol above and we will not repeat them here. However, we would like to stress the point of checking for anemia - ie. checking the patients blood hemoglobin levels which can easily be done by just a finger-prick blood test at the same time as checking for the HbA1c. Remember that anemia on top of poor arterial circulation will sabotage your attempts to get that wound to heal! A Hb of < 10 g/dl will almost always give delayed healing and a Hb <8 g/dl may cause the wound to not heal at all! In many parts of Africa where you do not have access to fancy reconstructive vascular procedures you can at least try to improve the patients hemoglobin levels! Remember also that the cause of the anemia may not always be easy to identify. If you find that your wound patient has low hemoglobin levels you will have to start the detective work of trying to find the cause of the anemia. This usually involves doing more labwork to look at signs of iron deficiency but also causes like chronic malaria, chronic hepatitis and other infectious diseases.
Examination of the lower extremities
When examining the lower extremities start by looking at the condition of the skin. Dry and hairless skin is typical of poor circulation ( atrophic skin). With impaired circulation the skin wil often be pale, but may also appear more reddish! In dark skin these changes can be more hard to detect. Poor circulation often also leads to changes in toenails - they become dystrophic and many confuse this with nail fungus. However- fungus thrives in these dystrophic nails so it can be difficult to distinguish dystrophy from fungal infection.
Look for deformities in the foot which predispose for pressure related injuries. Check the patients footwear for sharp or hard edges. Prevention of pressure in these ulcers is just as crucial as it is with other pressure ulcers or diabetic ulcers!
Evaluation of the arterial circulation
The following are common methods to assess the arterial circulation. Those highlighted in bold letters are the tests which can be done in a setting with limited resources.
Transcutaneos oxygen saturation
Colour duplex scan
Pulse-volume curves -pletysmograph
Radiological methods using contrast
We will briefly go through some of these tests:
Evaluation of the skin temperature is probably the simplest method to detect inadequate arterial circulation. It is a test with fairly low specificty though so we have to interpret our findings with care. Use your hands to feel whether the extremities are colder to the touch than expected and feel after differences in temperature between the two lower extremities. Note that most patients have quite symmetrical atherosclerosis i both legs so that you may not detect a temperature difference!
Many textbooks advise you to use the back of your hands to feel for a temperature difference as this area of your skin tends to be more temperature sensitive. This is not true for everybody - many colleagues say that they rather use the palms of their hands. Some colleagues use both the back of their hands and the palms of their hands for this test. Obviously, If you use gloves you will be less likely to detect subtle changes in temperature.
Figure 2 When you evaluate skin temperature use the back of your hands as they usually are more sensitive to temperature differences than your palms.
A more exact method of measuring the skin temperature is using an infrared thermometer. Even if you have limited resources available we strongly advise you to try to purchase such a thermometer. It can be a very useful tool for your clinic also when examining other types of wounds! If you do some searching online you may get hold of such a thermometer for about 30 US dollars. This is the same type of thermometer which are sold in most health care related shops for measuring fever. However, we have tested a number of these thermometers and the one we found to give us the most consistent results is an infrared thermometer which is actually used to measure surface temperatures for industrial purposes!
When measuring the surface of the skin the temperature recorded will not be the same as the body temperature - the skins surface is always some degrees cooler than the core temperature of the body. There is no standard surface temperature for our skin - this will be dependent on many factors. When using an infrared thermometer for assessing the blood circulation we are interested in the differences in skin temperature - not the absolute values. For example, if we measure 32 degrees on the back of the right foot and 30 degrees on the back of the left foot this could be a signed of decreased circulation in the left lower extremity. Again, using a thermometer to assess circulation is by no means an exact method but in a work place with limited resources it may be the most advanced option you have available. In the chapters on other wounds ( for example diabetic foot) we will talk more about other areas of woundcare where such a thermometer can be useful.
Figure 3 Using an infrared digital thermometer can be a useful method to assess skin temperature. Note that the surface temperature of the skin on the legs and feet always will be lower than the bodys core temperature. There is no standard as to what is a normal surface temperature of the skin on the legs and feet as this is quite individual and depends on many factors including the room temperature and humidity. Investing in such a thermometer can also aid in diagnosing other conditions than reduced arterial circulation. In the picture above we see the feet of a diabetic patient who had increased surface temperatures in the left foot due to an inflammatory condition called Charcot foot.
Have the patient lying down with the feet at about the level of the heart. Use your fingers to press with moderate pressure for at least 5 seconds on the foot ridge or over the nailbed of a toe. When you release the pressure you will see a paler mark and you count the seconds until the skin colour has normalized. This usually takes 2-3 seconds in healthy individuals. If it takes longer time this can be a sign of impaired arterial circulation. Be aware that this is quite a crude test and there are many pitfalls that can mislead you. For example patients with generally cold feet can have a positive capillary refill test without the circulation being impaired. Edema of various causes, low blood pressure and anemia can also mislead you. However, in combination with other tests the result of the capillary refill test can give valuable clues. If the capillary refill test is normal, the skin temperatures are unremarkable and you find a normal ankle-brachial-index ( see below) you can conclude with certainty that there is no critical impairment of the arterial circulation. Even though the capillary refill test has its limitations we usually perform it since it gives us a rough idea about the circulation status. It is also a useful test to check for differences between the left and right foot.
Figure 4 Capillary refill: Here we pressed on the nail bed of the big toe for five seconds. Note the pale nailbed in the middle picture when the presure is released. Within 3 seconds the nail bed had regained its normal colour (right picture).
Palpating the pulses of the foot
You may choose to hop over the capillary refill test. It is however essential to palpate the pulses of two easily accessible arteries of the foot. Arteria dorsalis pedis runs on the back of the foot parallel to the extensor tendon of the big toe and arteria tibialis posterior runs right behind the medial malleolus. As a rule of thumb it is difficult to palpate a pulse in these arteries if the patients systolic blood pressure is below 80mmHg and if you cannot detect a palpable pulse this indicates that the pressure in the artery is lower than this level.
Even if you have a doppler machine available you should have as habit to always palpate the pulses with your fingers beforehand. Not only will this make it easier for you to find the artery when placing the doppler probe but it will give you a clue about what to expect. As a rule of thumb- if you can palpate the arterial pulse with your finger the circulation is usually " not too bad".
Figure 5 Landmarks for finding the relevant arteries in the foot. Left: Arteria dorsalis pedis ( red dotted line) runs parallel to the extensor tendon of the big toe. Right: Arteria tibialis posterior runs approximately a fingers width behind the medial malleolus
Ankle-Brachial Index (ABI)
Measuring the ankle-brachial index is an important test to evaluate the severity of the circulation impairment and whether the patient is in need of more advanced treatment. The method is easy to learn and requires only a blood pressure cuff and a handheld vascular doppler machine. The price for a vascular doppler lies from 200 US dollars upwards and understandably only few health personell in Africa have access to this. Since an evaluation of the ABI is very important also for venous- and diabetic ulcers we have written a seperate chapter for ABI. Here we also come with some suggestions for work-arounds when you dont have access to a vascular doppler. Did you know for example that you can use a stethoscope and a bloodpressure cuff to try to measure the ankle-brachial index? You can also try to use a pulse-oximeter on the big toe if you dont have a doppler available but this method is more prone to error. Click on the picture below to go to this chapter.
Figure 6 You can measure the ankle-brachial index with a handheld vascular doppler ( right) or with a fully automatic machine with several cuffs (left) Understandably many health personell in Africa wont have access to this kind of equipment. We have written a more detailed chapter on ABI. Here we also provide some work-around solutions when you dont have access to this type of apparatus. Click on the picture above to get to this chapter.
Other non-invasive methods
There are many other methods to measure the arterial circulation. This can involve for example transcutaneous oxygen measuements, colour duplex scanning, systolic toe pressure or pulse-volume curves from a pletysmograph. These are tests that require more sophisticated equipment and are usually done at more advanced clinics. We will therefore not go into more detail here.
Using contrast to check arterial circulationon
To find out where the stenotic passages are in an artery we have do perform a radiological examination using contrast injected into the arteries - a so called angiogram. This can be performed with conventional xrays but most clinics use CT or MRI machines today. The contrast is injected into the arteries and pictures are taking with fast sequences. Care has to be taken with patients with renal insufficiency when using contrast as this may worsen the renal function. These patients have to take blood tests beforehand to check the creatinine levels and the glomerulo filtration rate (GFR). Keep in mind that many patients with artherosclerosis in the lower extremities also have renal insufficiency. Patients with impaired renal function may have to get fluid therapy prior to and after a vascular examination using contrast. Another possibility is to do a so called selective angiogram where only the affected lower extremity is injected with contrast thereby needing lower amounts of contrast agent (kidney sparing dose). If a MRI machine is available it is preferrable doing an angiogram there. This technique uses a different type of contrast which is tolerated better by the kidneys.
Note that there also are interactions between contrast and other medications. The radiological department will for example require information on whether the patient is using metformin - an oral antidiabetic agent. If a patient receiving iodinated contrast experiences renal failure then medication with metformin can lead to a toxic accumulation of the drug leading to lactic acidosis - a serious condition. To avoid this complication many x-ray departments demand that metformin is withheld for 48 hours after the contrast agent is administered. If renal function is normal at 48 hours, the metformin can be restarted.
Figure 7 Using contrast which is injected into the blood vessels it is possible to visualize the locations of stenotic passages in the arteries . This technique is called angiogram. This can be done using conventional x-rays, or more commonly CT or MRI techniques. In this example we saw decreased circulation starting in the area of the left thigh.