Capillary refill time paradoxically decreases in a blood loss shock model.

Background: This study aimed to investigate whether changes in capillary refill (CR) time precede macrovascular signs of deterioration in a human model of blood loss shock. The study was conducted at the Department of Emergency Medicine in Linköping, Sweden, and involved 42 healthy volunteers aged 18-45. Participants were randomized into two provocations of applied lower body negative pressure (LBNP): a stepwise escalation protocol and a direct application protocol, to simulate gradual and acute blood loss.