Understanding the intra-observer variability of the CRT was a primary goal of the study. Finally, they noticed fingertip CRT in sepsis patients with volume expansion within the first 24 hours of ICU admission. After receiving a crystalloid infusion, fingertip CRT was measured every 2 minutes for 30 minutes (500 mL over 15 min). As a first step, the reliability of repetitive fingertip CRT measures in 40 critically ill patients was evaluated. The degree of reproducibility was high; the intraclass correlation value was 99.5% (95% CI [99.3, 99.8]). Any change in the CRT that lasted longer than 0.2 s was considered to be noteworthy. The effects of volume expansion on CRT were then evaluated in 29 patients with septic shock; the SOFA median score was 7 [5-9], the SAPS II median score was 57 [45-72], and the ICU mortality rate was 24%. 23 patients, out of six who were initially expected to respond, actually did so (their CRT dropped by < 0.2 s 30 minutes after volume expansion). It was observed that the responders’ fingertip CRT immediately improved once the crystalloid infusion began, with a significant drop occurring between 6 and 8 minutes later. Optimism peaked at 10–12 minutes into the 30 minute period and persisted throughout (-0.7 [-0.3; -0.9] s.). There was a significant relationship between CRT fluctuations and initial CRT readings (R=0.39, P=0.05). After the fluid infusion had begun, the CRT dropped dramatically, reaching a minimum between 6 and 8 minutes later. Next, the volume was turned up, which made the song sound significantly better.

Source: annalsofintensivecare.springeropen.com/articles/10.1186/s13613-022-01049-x