Temporal Evolution of the PcvCO2-PaCO2/CaO2-CcvO2 Ratio vs Serum Lactate during Resuscitation in Septic Shock.

Abstract

BackgroundLactate as a target for resuscitation in patients with septic shock has important limitations. The PcvCO2–PaCO2/CaO2–CcvO2 ratio may be used as an alternative for the same. The primary outcome of the study is to evaluate the correlation between serum lactate and PcvCO2–PaCO2/CaO2–CcvO2 ratio measured at various time points to a maximum of 24 hours in patients with septic shock [mean arterial pressure (MAP) <65 mm Hg]. The secondary outcomes were to study the (1) relationship between the PcvCO2–PaCO2/CaO2–CcvO2 ratio and lactate clearance at 6, 12, and 24 hours as compared to the initial serum lactate, (2) to ascertain whether the PcvCO2–PaCO2/CaO2–CcvO2 ratio and the arterial lactate levels in the first 24 hours are able to predict mortality at day 28 of enrollment, and (3) to determine whether the PcvCO2–PaCO2/ CaO2–CcvO2 ratio and arterial lactate are useful in discriminating survivors from nonsurvivors.Materials and methodsThirty patients with sepsis-induced hypotension who were being actively resuscitated were enrolled. Paired arterial and central venous blood samples were obtained 0.5 hourly till stabilization of MAP and 6 hourly thereafter for the first 24 hours. Patients were followed up to day 28 of enrollment for mortality and organ system failure.ResultsA positive correlation was observed between arterial lactate and PcvCO2–PaCO2/CaO2–CcvO2 ratio at 0, 6, 12, and 18 hours (R = 0.413, p = 0.02; R = 0.567, p = 0.001; R = 0.408, p = 0.025; R = 0.521, p = 0.003, respectively). No correlation was seen between PcvCO2–PaCO2/CaO2–CcvO2 ratio and lactate clearance. The subgroup analysis showed that PcvCO2–PaCO2/CaO2–CcvO2 ratio >1.696 at 24 hours of resuscitation predicted 28-day mortality (sensitivity: 80%, specificity 69.2%, area under the receiver operating characteristic curve 0.82).ConclusionThe PcvCO2–PaCO2/CaO2–CcvO2 ratio and lactate are positively correlated during the first 24 hours of active resuscitation from sepsis-induced hypotension, and a threshold of 1.696 mm Hg/mL/dL at 24 hours significantly differentiates survivors from nonsurvivors (CTRI/2017/11/010342).How to cite this articleMadabhushi S, Trikha A, Anand RK, Ramachandran R, Singh PM, Rewari V. Temporal Evolution of the PcvCO2–PaCO2/CaO2–CcvO2 Ratio vs Serum Lactate during Resuscitation in Septic Shock. Indian J Crit Care Med 2021; 25(12):1370–1376.