What should be used for fluid resuscitation: crystalloids or colloids?

There has been an ongoing debate regarding whether crystalloids or colloids should be used for fluid resuscitation. Both have their advantages and disadvantages. Crystalloids in excess can cause peripheral and pulmonary edema whereas colloids in excessive use can cause cardiac failure and well as edema peripherally and pulmonary. Intravenous fluid substitution for patients with predicted acute pancreatitis should be established with 250-350 ml/hr for the first 48 hours. Restoration of normal cardiocirculatory functions objectified by heart-rate, systolic or mean arterial blood pressure, and oxygen saturation of venous blood of > 95%, absence of a base deficit > 5 μmol/L and urine flow of ≥ 50 mL/h are decisive criteria of treatment response. Intravenous access and ideally a central venous catheter as well as a urinary catheter are essential for accurate fluid balance for fluid management. On the other hand, there are studies that have shown the downfall of early aggressive resuscitation and have hence recommended a controlled fluid expansion. A Swedish study demonstrated that administration of 4 litres of fluid within the initial 24 hour period increased the incidence of lung complications including atelectasis, pneumonia, and effusions although not that of pulmonary edema. It was however noted that patients who received a larger amount of fluids were sicker at presentation. A prospective, cohort, Spanish study involving 247 acute pancreatitis patients demonstrated that patients administered 4.1 litres during the first 24 hours had an increased incidence of pancreatic collections, persistent organ failure including respiratory and renal insufficiency.