Serum lactate and phosphate as biomarkers of intestinal ischemia in a Ugandan tertiary hospital: a cross-sectional study

BACKGROUND: Intestinal ischemia is a common complication of intestinal obstruction and arises from impaired perfusion. The resultant local and systemic inflammatory response and bacterial translocation come with a significant degree of morbidity and mortality. This study therefore aimed to investigate the predictive value of elevated levels of serum lactate and phosphate as biomarkers of intestinal ischemia among patients with mechanical intestinal obstruction. METHODS: This was a cross-sectional analytical study done at Mulago Hospital in Uganda. Ethical approval was obtained. All eligible patients had a blood sample drawn for assay analysis. Determination of bowel ischemia status was by physical examination at laparotomy. Analyses were performed using Stata software, version 10.1, and 2 × 2 tables were used to calculate sensitivity and specificity. RESULTS: Serum lactate was predictive of bowel ischemia, while phosphate was not. Of the 81 patients enrolled 70 qualified for analysis; 40/70 (57%) had ischemic bowel, while 30/70 (43%) had normal bowel. Among those with ischemic bowel, 28/40 (70%) had reversible ischemia, and 12/40 (30%) had irreversible ischemia. Serum lactate assay had a sensitivity of 66% and specificity of 53% for bowel ischemia in general and a higher sensitivity of 71% and specificity of 80% for irreversible bowel ischemia. Lactate was predictive of bowel ischemia in general (p = 0.011), PPV = 14%, but more significantly predictive of irreversible ischemia (p = 0.009), PPV = 42%. NPV for lactate in both forms of ischemia was 93%. Hernias (33/70, 47%) were the most common cause of intestinal obstruction. CONCLUSION: Serum lactate assay had moderate sensitivity for bowel ischemia due to acute mechanical intestinal obstruction. The assay can be used to aid diagnosis of bowel ischemia in low technology settings.