Mechanisms of Organ Failure

While most patients with acute pancreatitis (AP) have a mild clinical course, severe AP can develop in about a fifth of the cases [1], which increases the length of hospital stay and critical care requirements and is the leading cause of death in AP. This results in a mortality of 8–20% [2–4] and is due to failure of vital organs. Severity in AP is based on presence of organ failure as per the Revised Atlanta Criteria [5], which recommends that the severity of organ failure is scored by the modified Marshall score [5, 6]. The modified Marshall scoring system has specific metrics for vital organ systems, among which the respiratory, renal and cardiovascular systems are the most important and frequently involved systems. These metrics include creatinine for the renal system, partial pressure of oxygen for respiratory system and systolic blood pressure for the cardiovascular system. It also includes whether treatments such as oxygen, intravenous fluids and pressors are required. Severe AP is defined by organ failure lasting >48 h, i.e., persistent organ failure. The duration of organ failure likely depends on the risk factors for severity and the patient’s response to treatment [7]. Intravenous fluid resucitation is the current treatment standard for AP. Aggressive fluid resuscitation [8] can worsen organ failure. Severe AP can develop single or multiple organ failure [5], with the latter being associated with higher mortality [9]. Thus, an increased number of organs with dysfunction during AP is associated with increased severity of AP [5]. Recent large studies show that respiratory and cardiovascular failure are more important in determining mortality in severe AP than renal failure [10]. Here we will focus on the mechanisms underlying organ failure.