**4. First 72 hours treatment steps according to the International Guideliness**

Severe cases with ABP should be hospitalized in spesific centers having MRCP, ERCP and preferably EUS facilities under the control of a team of physicians consisted of gastroenterologist, pancreatobiliary surgeon and invasive radiologist [30–35]. First, the severity of AP in accordance with the international scoring models must be determined and the patient's co-morbidities should be recorded. Thereafter, these patients should be vigorously hydrated to prevent the collapse of pancreatic circulation. Indeed, we will especially emphasize aggressive fluid replacement therapy in these patients in the first 3 days of admission with patients with AP. This issue is also very important for the prophylaxis of post-ERCP pancreatitis [36].

A meticiluos fluid replacement within this very 24 hours limits pancreatitis by correcting the hypovolemia and organ hypoperfusion, hinders local and systemic complications of AP by decreasing Systemic Inflammatory Response Syndrome (SIRS) and associated multiorgan failure and lowers inhospital mortality. This helps to improve the general status of the patient and decreases the risks of further invasive procedures like ERCP in these circumstance. During the first 24 hours,

iv crystalloid and or colloid solutions can be given [30–35, 37, 38]. Although a retrospective study depicted no difference between ringer lactate (RL) and normal saline (SF) infusion with regard to the severity and complications of pancreatitis [39], there are vast data from the experimental and clinical studies supporting the benefits of RL; such as RL infusion hampers hyperchloremic acidosis and other metabolic complications of AP and by improvinng intraparenchymal pH status, RL infusion inhibits zymogen activation and worsening of AP [40, 41]. For these reasons, RL has been suggested by many international guidelines as first choice to be used as fluid therapy in these patients with AP [30–36]. In the absence of heart and kidney failure, RL infusion at 5–10 ml/kg/hour dose within the first 24 hours is recommended to these patients as targeted fluid therapy. By this way, we aim to get normal hemodynamic parameters, urine output 0.5–1 ml/kg/hour and hematocrit value as between 35–44%. However, we need to be scrupulous to avoid hypervolemia in elderly patients during fluid recesutation. Therefore, it is important to limit the dose to 5 to 10 ml/kg/hour as more than 10 ml/kg/hr. infusion rate has been associated with mehcanical ventilation, abdominal compartment syndorme and increased mortality [42].
