Capillary refill time response to a fluid challenge or a vasopressor test: an observational, proof-of-concept study

• Published in: Annals of intensive care 2024-04, Vol.14 (1), p.49-49, Article 49
• Main Authors: Hernández, Glenn, Valenzuela, Emilio Daniel, Kattan, Eduardo, Castro, Ricardo, Guzmán, Camila, Kraemer, Alicia Elzo, Sarzosa, Nicolás, Alegría, Leyla, Contreras, Roberto, Oviedo, Vanessa, Bravo, Sebastián, Soto, Dagoberto, Sáez, Claudia, Ait-Oufella, Hafid, Ospina-Tascón, Gustavo, Bakker, Jan
• Format: Article
• Language: English
• Subjects: Anesthesiology; Capillary refill time; Critical Care Medicine; Emergency Medicine; Fluid challenge; Hemodynamics; Hypertension; Intensive; Intensive care; Life Sciences; Medicine; Medicine & Public Health; Mortality; Perfusion; Physiology; Sepsis; Septic shock; Vasopressor test
• ISSN: 2110-5820; 2110-5820
• DOI: 10.1186/s13613-024-01275-5

Background Several studies have validated capillary refill time (CRT) as a marker of tissue hypoperfusion, and recent guidelines recommend CRT monitoring during septic shock resuscitation. Therefore, it is relevant to further explore its kinetics of response to short-term hemodynamic interventions with fluids or vasopressors. A couple of previous studies explored the impact of a fluid bolus on CRT, but little is known about the impact of norepinephrine on CRT when aiming at a higher mean arterial pressure (MAP) target in septic shock. We designed this observational study to further evaluate the effect of a fluid challenge (FC) and a vasopressor test (VPT) on CRT in septic shock patients with abnormal CRT after initial resuscitation. Our purpose was to determine the effects of a FC in fluid-responsive patients, and of a VPT aimed at a higher MAP target in chronically hypertensive fluid-unresponsive patients on the direction and magnitude of CRT response. Methods Thirty-four septic shock patients were included. Fluid responsiveness was assessed at baseline, and a FC (500 ml/30 mins) was administered in 9 fluid-responsive patients. A VPT was performed in 25 patients by increasing norepinephrine dose to reach a MAP to 80–85 mmHg for 30 min. Patients shared a multimodal perfusion and hemodynamic monitoring protocol with assessments at at least two time-points (baseline, and at the end of interventions). Results CRT decreased significantly with both tests (from 5 [3.5–7.6] to 4 [2.4–5.1] sec, p  = 0.008 after the FC; and from 4.0 [3.3–5.6] to 3 [2.6 -5] sec, p  = 0.03 after the VPT. A CRT-response was observed in 7/9 patients after the FC, and in 14/25 pts after the VPT, but CRT deteriorated in 4 patients on this latter group, all of them receiving a concomitant low-dose vasopressin. Conclusions Our findings support that fluid boluses may improve CRT or produce neutral effects in fluid-responsive septic shock patients with persistent hypoperfusion. Conversely, raising NE doses to target a higher MAP in previously hypertensive patients elicits a more heterogeneous response, improving CRT in the majority, but deteriorating skin perfusion in some patients, a fact that deserves further research.