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Capillary refill time (CRT) is a useful and rapid metric in determining the intravascular volume status of ill patients, particularly those with conditions that arise or result from hypovolemia. Examples of these pathologic states include but are not limited to hypo and hyperthermia, all forms of shock, hemorrhage, loss of plasma volume in burns, gastrointestinal losses through diarrhea or vomiting, over-diuresis, and anaphylactic reactions.[1] Information obtained from CRT assessment can then guide fluid resuscitation strategies, reassess an implemented therapy, and define the endpoint of treatment. Volume status can also be assessed via other clinical exams and objective measurements. Briefly, markers of reduced perfusion include abnormal vital signs (hypotension, tachycardia, increased pulse pressure variation) and deranged physical exam findings (delayed CRT, dry mucous membranes, poor skin turgor, absence of diaphoresis, altered mental status). More objective indicators of hypovolemia include laboratory abnormalities (increased BUN, increased creatinine, increasing lactate, fluctuating hemoglobin levels, increased urine specific gravity, oliguria, or anuria) and radiographic derangements (increased collapsibility of the IVC on ultrasound, reduced cardiac chamber diameters on ultrasound or CT, changes in transpulmonary thermodilution).[1][2] While accurate assessment of intravascular volume status is best accomplished through a combination of these methods, this article will focus specifically on measuring capillary refill time and its growing application in guiding medical diagnosis and subsequent management.

While accurate assessment of intravascular volume status is best accomplished through various methods, CRT can provide rapid and practical information regarding peripheral perfusion status without the associated patient inconvenience, cost, or time delay associated with more conventional markers. As demonstrated by the ANDROMEDA-SHOCK trial, its utility extends beyond diagnostic purposes and may be used to guide fluid resuscitation strategies in unstable patients. While interpretation is subject to external factors and examiner variability, developing newer technologies to measure CRT emphasizes its usefulness and emerging role in medicine. Capillary refill time is an easily performed and interpreted examination, and all interprofessional team members should at least be knowledgeable regarding the importance and interpretation of results. This includes clinicians, specialists, mid-level practitioners, and nurses, all sharing information and coordinating activities to optimize patient outcomes. [Level 5]