Title : Use of Blood Tests and ABG in the Diagnosis of Acute Mesenteric Ischemia
Abstract:
Aim: To investigate the usefulness of commonly used blood tests and Arterial Blood Gas results in the diagnosis of Acute Mesenteric Ischemia Methods: All patients with acute mesenteric ischemia (AMI) who presented to a single tertiary hospital in Perth, Western Australia over a 10-year period were analyzed. Blood test results including White Cell count (WBC), CRP and hemoglobin (Hb) levels where investigated. From the ABG, patients’ pH, Base excess (BE) and Lactate level where investigated. A control group was created using patients with other severe acute intra-abdominal pathologies including bowel obstruction, diverticulitis, inflammatory bowel disease and severe pancreatitis. The blood test results were compared using ANOVA analysis Results: A total of 68 patients with AMI were identified, Male to female 1:1, average age 67 (range 33-94) and compared to 39 patients in the control group: male to female 1.6:1, average age 69 (range 25- 96). While patients’ comorbidities of hypertension, ischemic heart disease, atrial fibrillation, diabetes and COAD were comparable, the prevalence of peripheral vascular disease was significantly higher in patients with AMI (p=0.001). Only lactate levels were statistically different between the groups: 4.2 vs 2.3 mmol/L (p= 0.014), however, all other blood tests, did not show a meaningful difference: WCC 20.7 vs. 12.8 × 109/L, Hb 106 vs. 117 g/L, CRP 121 vs. 127 mg/L, pH 7.32 vs. 7.35 and BE -3.1 vs. -3.8 mEq/L. Further analysis of the lactate levels revealed high variation (0.5 to 19). Histogram analysis showed that the majority of patients (42 of 68) had only mildly elevated lactate levels (0.5 to 4.1 mmol/L), a further 11 patients had lactates of 4.1-7.7 mmol/L and only a minority of patients had lactate levels > 7.7 mmol/L. Conclusion: Overall, the commonly used blood investigations cannot distinguish between acute mesenteric ischemia and other serious intra-abdominal pathologies. Only lactate is shown to be of statistical use. However, due to large variation in lactate levels, it remains an unreliable investigation for the diagnosis of AMI. Audience Take Away: • How to use widely available blood tests to diagnose mesenteric ischemia. The early diagnosis of acute mesenteric ischemia is critical to patient survival. The diagnosis is difficult to make clinically. While imaging provides additional information, it is not always available or not available in a timely manner. The possibility of using simple blood tests to diagnose mesenteric ischemia quickly will help surgeons to manage patients appropriately. • Our research affirms previous studies that Arterial Blood Gas Lactate level is useful in the diagnosis of mesenteric ischemia. However, other biochemical markers are of limited value. • Further clinical based research should be performed on different biochemical markers.
