Arterial pH, bicarbonate levels and base deficit at presentation as markers of predicting mortality in acute pancreatitis: a single-centre prospective study

BACKGROUND Arterial blood gas (ABG) parameters such as pH form part of multi-parameter scoring systems for predicting severe acute pancreatitis; however, literature on detailed evaluation of ABG alone in this context is scarce. METHODS Patients with acute pancreatitis presenting to our unit between January 2012 and November 2013 were prospectively studied. ABG analysis was done at admission and development of organ failure, any need for intervention, and mortality were noted. The association between various parameters of ABG analysis and the development of organ failure or local complications, need for interventions (endoscopic/radiological/surgical) and mortality were analysed. RESULTS Two hundred and five patients (mean age: 39.33 ± 13.85 years; 61.0% males) were prospectively studied. The aetiology of acute pancreatitis was alcohol in 93 patients (45.4%) and gall stone disease in 73 (35.6%). Organ failure developed in 71.2% patients and 83.9% had local complications. In 18% of patients, endoscopic/radiological/surgical interventions were needed and 14.6% died. The patients (n = 35) with metabolic acidosis (pH <7.35) suffered higher frequency of organ failure, need for interventions and mortality. Patients with low arterial bicarbonate levels, as well as higher base deficit, also displayed higher frequency of organ failure, need for interventions and mortality. The receiver operating characteristic (ROC) curves for pH <7.35, bicarbonate <22 meq/L and base deficit of >-4 meq/L for prediction of mortality were 0.771 (95% CI: 0.664-0.878), 0.707 (95% CI: 0.622-0.791) and 0.780 (95% CI: 0.693-0.867), respectively. CONCLUSION Arterial pH, bicarbonate levels, and base deficit at presentation are useful early markers for predicting adverse outcome in acute pancreatitis.