[Persistent inflammation immunosuppression catabolism syndrome: a special type of chronic critical illness]

After the concept of "chronic critical illness (CCI)" was proposed, the new concept persistent inflammation immunosuppression catabolism syndrome (PICS) is present recently. Patients with PICS are manifested by fast decreasing body weight, poor nutritional status, long-term immunosuppression and repeated nosocomial infections. These patients are faced with great challenges of persistent inflammation, acquired immunosuppression and high catabolism, which finally results in repeated nosocomial infections, prolonged hospital stay and increased mortality. At present, main problems of PICS diagnosis standard include varying length of ICU stay, difference in normal C reactive protein value, poor value of nutrition indexes, absence of clinical verification. Though associated pathophysiology mechanism is not clear, PICS is preventable and magageable with certain therapy, including early comprehensive prevention and treatment focused on infection control for CCI patients to stop the progression of PICS, application of immune modulator to improve immune function and prognosis of patients, and reasonable nutritional support and treatment. Besides, through the analysis of the association between PICS and CCI, authors draw a conclusion that PICS is a new phenotype of CCI, and immune paralysis is its main feature.