Point of care lactate for differentiating septic shock from hypovolemic shock in non-ICU settings: a prospective observational study

Background

Septic shock and hypovolemic shock are life-threatening illnesses that necessitate immediate recognition and intervention, as they can result in deadly consequences. While the underlying processes may vary, both entities can exhibit hypotension and organ dysfunction. No studies have been conducted on bedside testing to differentiate between these illnesses. Lactate measurement has been established as a viable option for early detection of septic shock. However, its role in diagnosing hypovolemic shock has yet to be evaluated. The aim of the study was to investigate alterations in lactate levels among diarrheal patients with septic shock and hypovolemic shock following the administration of first fluid resuscitation.

Methods

We conducted a prospective observational study in critically ill diarrheal adults aged ≥18 years in the emergency ward in Dhaka Hospital of icddr,b from 21st October 2021 to 31st May 2023 (total 19 months). The enrollment process was operational between 8:30 AM and 5:00 PM. Diarrheal adults with a diagnosis of sepsis with shock featured with poor peripheral perfusion (characterized by cold periphery and weak or absent pulse and capillary refill time >3 s) or hypotension (characterized by mean arterial pressure <65 mm-Hg) were enrolled as cases and consecutive diarrheal patients without any obvious features of sepsis with hypovolemic shock (due to severe dehydration) comprised the comparison group. POC lactate test was done at hours 0, 1st and 6th by StatStrip Lactate meters (Nova Biomedical, US) to all enrolled patients. For comparison of POC lactate levels, we used paired t-test for comparing the lactate samples drawn at hour 0, hour 1 and 6 with the septic shock and hypovolemic shock group. Odds ratio (OR) and their 95% confidence intervals (CIs) were used to demonstrate the strength of association. The study was registered at Clinicaltrials.gov (NCT05108467) and received institutional ethical approval (PR-21097).

Findings

Of 435 patients, 135 had septic shock and 141 had hypovolemic shock, rest 41 patient responded with fluid bolus. 25% (34/135) of the people in the septic shock group died whereas there is no mortality in the hypovolemic shock group. The number of patients visiting from outside Dhaka city had more septic shock than from inside were higher in comparison with (55% vs. 28%; p < 0.001). Statistically significant difference was observed between septic shock and hypovolemic shock group for a median POC lactate in 0, 1st and 6th hours with an OR of 1.07 (95% CI: 0.99, 1.17; p = 0.039); 1.48, (95% CI: 1.28, 1.70; p < 0.001) and 2.36 (95% CI: 1.85, 3.00; p < 0.001), respectively. The gradient of 1st to 2nd sample between septic shock and hypovolemic shock was found to be significantly different (OR: 0.74, 95% CI: 0.64, 0.85; p < 0.001).

Interpretation

POC lactate test can detect septic shock by differentiating hypovolemic shock in diarrheal patients. By providing quick, reliable and accurate result this test can help clinicians quickly diagnose and treat time-sensitive condition, like septic shock.

Funding

The study was funded by Global Affairs of Canada (GR-01726). The donors had no role in the design, implementation, analysis, data interpretation or writing manuscript, or decision to publish. The corresponding author had access to all data and takes responsibility for the final approval and submission of the manuscript.