Markers of tissue hypoperfusion in pediatric septic shock

Abstract

Objective: To describe measurements of global oxygenation parameters, markers of splanchnic hypoperfusion and those of metabolic activity related to cellular energy production among critically ill children with septic shock.¶Design: Clinical study of a series of cases.¶Patients and participants: 11 previously healthy children with septic shock admitted to the pediatric intensive care unit (ICU) of a university hospital.¶Interventions: None.¶Measurements and results: Oxygen consumption, oxygen delivery (DO₂), serum bicarbonate, arterial pH, gastric intramucosal pH (pHi), gastroarterial carbon dioxide tension gradient, serum lactate, pyruvate, lactate to pyruvate ratio (L/P), ketone body ratio, and the esterified to free carnitine ratio were measured serially at 0, 6, 12, 24, 36, and 48 h after admission to the pediatric ICU. All children survived. One patient failed to show supranormal DO₂ ( > 570 ml/min per m²). Normalization of serum bicarbonate and lactate were associated with patient recovery. One patient presented an increasingly abnormal L/P ratio with normal lactate levels, suggesting an increased utilization of pyruvate rather than an increased cytosolic redox potential. Although values of gastric pHi < 7.30 were observed in 43 % of samples, serial measurements in individuals showed significant variability and unpredictable trends. Free fatty acid concentrations, ketone body production, and carnitine levels remained within the normal range.¶Conclusions: In this study, trends in serum bicarbonate and lactate somewhat characterized the recovery of children with septic shock. Based on our data, it is unclear how other markers may have been used to modify therapy.