Can plethysmographic capillary refill time predict lactate during sepsis? An observational study from Morocco

Area of Science:

• Critical Care Medicine
• Emergency Medicine
• Clinical Physiology

Background:

• Blood lactate is a key marker for tissue hypoxia and guiding resuscitation in sepsis.
• Capillary refill time (CRT) assesses tissue perfusion but faces challenges in precision and reproducibility.
• Blood lactate measurement is often unavailable in resource-limited African emergency departments.

Purpose of the Study:

• To evaluate the accuracy of visual capillary refill time (V-CRT) compared to plethysmographic CRT (P-CRT) in predicting arterial lactate levels in septic patients.
• To determine if P-CRT offers improved accuracy over V-CRT in this clinical context.

Main Methods:

• A prospective observational study involving 43 patients with sepsis or septic shock.
• Simultaneous measurements of V-CRT, P-CRT, and arterial lactate levels upon admission.
• ROC curve analysis to assess the precision of V-CRT and P-CRT in predicting arterial lactate.

Main Results:

• Both V-CRT and P-CRT showed significant correlations with arterial lactate (r=0.529 and r=0.517, respectively).
• V-CRT demonstrated satisfactory accuracy in predicting lactate levels >2 mmol/l (AUC=0.8), outperforming P-CRT (AUC=0.73).
• Optimal thresholds were 3.4s for V-CRT (sensitivity 90%) and 4.1s for P-CRT (sensitivity 85%).

Conclusions:

• Plethysmographic CRT did not enhance the accuracy of CRT for predicting lactate levels compared to visual assessment.
• V-CRT serves as a viable and accurate surrogate for lactate measurement in septic patients, particularly in low-income settings.
• V-CRT can aid in assessing circulatory status and guiding resuscitation when lactate testing is not feasible.