When you assess capillary refill time in an infant normal color to the tested area should return within?

20 July, 2020

Capillary refill time is a simple bedside measurement that is undertaken as part of the ABCDE approach to assessing acutely ill patients. This article outlines the rationale for measurement and provides a step-by-step guide to the procedure

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The Capillary refill test (CRT) is a rapid test used for assessing the blood flow through peripheral tissues. It's a quick test performed on the nail beds to monitor the amount of blood flow to tissues and dehydration. [1] The CRT measures the efficacity of the vascular system of hands and feet as they are far from the heart. [2]

Alternative names[edit | edit source]

The Capillary refill test is also called: [1]

• Digit blood flow test
• Capillary refill time
• Capillary nail refill test

Procedure[edit | edit source]

The following steps have to be followed when doing the test: [3]

Step1. Remove finger rings and nail polish.

Step2. The therapist compresses the nail bed until it turns white and records the time taken for the color to return to the nail bed.

Step3. It normally takes 3 seconds or less. When it takes longer, arterial insufficiency is suspected.

Step4. Always compare to the normal side of the hand or fingers.

Although the CRT is used in both children and adults [4], there is less literature about its use among adults [1] as well as very little research information about its validity. [5]

1. Interpretation of Results

The CRT is largely recommended in the routine of unwell patients and should last less < 2 seconds. If the color is pink after there is no more pressure; it indicates a good blood flow to the finger.t It's part of the assessment of patients seriously ill. [4]

2. Abnormal Results

A CRT> 2 seconds or prolonged CRT is suggestive of an early sign of shock. [5]

Several other factors can affect the CRT measurement and therefore its results. They may include: [4] [5]

• Peripheral vascular disease
• Hypothermia
• Cold ambient temperature
• Poor lighting
• Old age
• Pressure application
• Intra and interobserver reliability

The ABCDE approach used by nurses to assess and treat severely ill patients has 5 components namely: Airway, Breathing, Circulation, Disability, and Exposure. Although the CRT represents a big part of the Circulation during this assessment, a thorough examination should be done and should include:[5]

• Pulse rate
• Pulse volume
• Blood pressure
• Level of consciousness
• Skin color/ temperature/texture
• Urine output
• as well as other clinical findings of the ABCDE approach/assessment

The ABCDE assessment looks for life-threatening conditions and therefore brings lifesaving interventions to critically ill patients. [6] .

The capillary refill test, also called capillary refill time (CRT) or nail blanch test, is a technique that nurses use to assess for peripheral perfusion or dehydration in patients.

How is the Capillary Refill Test Performed?

Nurses typically perform the capillary refill test by pressing on the nail plate or the pad of a digit for around 5-10 seconds, causing the nail bed (or pad of digit) to lighten in color as the blood is expelled.

The nurse then releases the digit and observes the number of seconds it takes for the tissue to regain its natural color as blood flow resumes.

Note: The capillary refill test may sometimes be performed on the sternum or forehead in some patient populations, such as newborns [1].

Normal vs Abnormal Capillary Refill Time

If the blood flow returns to the tissue within 2 seconds (depending on your facility’s protocols), it is considered a normal finding, but longer than 2 seconds could be considered abnormal and should be reported immediately.

Note: Some guidelines or studies suggest that a capillary refill of up to three seconds could be normal in some patient populations [1], so always refer to your facility’s protocols for details.

What Causes an Abnormal Capillary Refill Time?

A capillary refill test of longer than 2 or 3 seconds could indicate that the patient is experiencing poor peripheral perfusion (blood flow to the extremities) or even dehydration.

Some examples of factors that can cause poor peripheral perfusion include the following:

• Decreased cardiac output: This may be due to shock, heart failure, anemia, and other similar conditions
• Bone fractures: compartment syndrome may develop during a fracture, which can restrict blood flow in the affected limb
• Cast care and placement: If a cast is placed on a broken limb, capillary refill time is often assessed to ensure that proper blood flow is reaching the extremity and that the cast is not too tight
• Peripheral vascular disease: In peripheral vascular disease, the narrowing of vessels can reduce tissue perfusion
• Raynaud’s disease: this can cause vessels to spasm and/or narrow in extremities that are exposed to cold, which reduces blood flow
• Hypothermia

In addition, some of the factors below may affect the reliability of the capillary refill test or lead to longer than normal capillary refill time:

• Colder temperatures (either the patient’s body or room temperature)
• Edema (swelling)
• Old age
• Smoking

How to Perform a Capillary Refill Test on a Fingernail

Here are some tips to perform the capillary refill test on a patient’s fingernail or pad of finger.

Note: This information is for educational purposes only. Before performing any nursing skills or assessments, it is important to verify the latest protocols for your facility, as nursing skills and assessment criteria may change over time.

1. Perform hand hygiene

2. Greet the patient, explain the procedure, and obtain consent.

3. Choose a digit without nail polish and anything that could restrict blood flow to the area, such as jewelry or a watch. If those items are present, you can either remove them or use an alternate site such as the pad (pulp) of the digit  or another digit instead.

4. Position the patient’s hand at or above heart level, and observe the patient’s natural skin color at the nail bed (or finger pad) for reference.

5. Press on the nail plate (or pad of the finger) firmly for 5-10 seconds to expel blood from the tissue.

6. Release the fingernail (or pad of finger), and observe the number of seconds it takes for the tissue to return to its normal color, which indicates perfusion of the tissue. For accurate results, use a digital watch with a start/stop function to count the seconds as you observe the digit. Next, compare the results to a digit from another limb, if necessary.

7. If the skin’s natural color returns within 2-3 seconds (depending on your facility’s protocol), the capillary refill test is considered normal. If the capillary refill time is longer than 2-3 seconds, it could suggest poor tissue perfusion or dehydration, and these findings should be reported immediately. Note: Again, refer to your facility’s protocols to determine the appropriate guidelines for normal vs. abnormal refill time, as guidelines may vary for different facilities or different patient populations.

8. Perform hand hygiene, and document the capillary refill time (in seconds), including the location of the assessment (example: capillary refill was 2 seconds on fingernail of right index finger) and other necessary information, per your facility’s protocol.

References:

1. Strozik, K. S., Pieper, C. H., & Roller, J. (1997). Capillary refilling time in newborn babies: normal values. Archives of disease in childhood. Fetal and neonatal edition, 76(3), F193–F196. https://doi.org/10.1136/fn.76.3.f193