The association between prolonged capillary refill time and microcirculation changes in children with sepsis.

BACKGROUNDS: In children with sepsis, circulatory shock and multi-organ failure remain major contributors to mortality. Prolonged capillary refill time (PCRT) is a clinical tool associated with disease severity and tissue hypoperfusion. Microcirculation assessment with videomicroscopy represents a promising candidate for assessing and improving hemodynamic management strategies in children with sepsis. Particularly when there is loss of coherence between the macro and microcirculation (hemodynamic incoherence). We sought to evaluate the association between PCRT and microcirculation changes in sepsis. METHODS: This was a prospective cohort study in children hospitalized with sepsis. Microcirculation was measured using sublingual video microscopy (capillary density and flow and perfused boundary region [PBR]-a parameter inversely proportional to vascular endothelial glycocalyx thickness), phalangeal tissue perfusion, and endothelial activation and glycocalyx injury biomarkers. The primary outcome was the association between PCRT and microcirculation changes. RESULTS: A total of 132 children with sepsis were included, with a median age of two years (IQR 0.6-12.2). PCRT was associated with increased glycocalyx degradation (PBR 2.21 vs. 2.08 microns; aOR 2.65, 95% CI 1.09-6.34; p = 0.02) and fewer 4-6 micron capillaries recruited (p = 0.03), with no changes in the percentage of capillary blood volume (p = 0.13). Patients with hemodynamic incoherence had more PBR abnormalities (78.4% vs. 60.8%; aOR 2.58, 95% CI 1.06-6.29; p = 0.03) and the persistence of these abnormalities after six hours was associated with higher mortality (16.5% vs. 6.1%; p < 0.01). Children with an elevated arterio-venous CO2 difference (DCO2) had an abnormal PBR (aOR 1.13, 95% CI 1.01-1.26; p = 0.03) and a lower density of small capillaries (p < 0.05). Prolonged capillary refill time predicted an abnormal PBR (AUROC 0.81, 95% CI 0.64-0.98; p = 0.03) and relative percentage of blood in the capillaries (AUROC 0.82, 95% CI 0.58-1.00; p = 0.03) on admission. A normal CRT at 24 h predicted a shorter hospital stay (aOR 0.96, 95% CI 0.94-0.99; p < 0.05). CONCLUSIONS: We found an association between PCRT and microcirculation changes in children with sepsis. These patients had fewer small capillaries recruited and more endothelial glycocalyx degradation. This leads to nonperfused capillaries, affecting oxygen delivery to the tissues. These disorders were associated with hemodynamic incoherence and worse clinical outcomes when the CRT continued to be abnormal 24 h after admission.

Capillary refill time in sepsis: A useful and easily accessible tool for evaluating perfusion in children.

The international sepsis guidelines emphasize the importance of early identification along with the combined administration of fluids, antibiotics and vasopressors as essential steps in the treatment of septic shock in childhood. However, despite these recommendations, septic shock mortality continues to be very high, especially in countries with limited resources. Cardiovascular involvement is common and, in most cases, determines the outcomes. Early recognition of hemodynamic dysfunction, both in the macro and microcirculation, can help improve outcomes. Capillary refill time (CRT) is a useful, available and easily accessible tool at all levels of care. It is a clinical sign of capillary vasoconstriction due to an excessive sympathetic response which seeks to improve blood redistribution from the micro- to the macrocirculation. An important reason for functionally evaluating the microcirculation is that, in septic shock, the correction of macrocirculation variables is assumed to result in improved tissue perfusion. This has been termed "hemodynamic coherence." However, this coherence often does not occur in advanced stages of the disease. Capillary refill time is useful in guiding fluid resuscitation and identifying more seriously affected sepsis patients. Several factors can affect its measurement, which should preferably be standardized and performed on the upper extremities. In this review, we seek to clarify a few common questions regarding CRT and guide its correct use in patients with sepsis.