Persistent Inflammation, Immunosuppression and Catabolism Syndrome.

Area of Science:

• Critical care medicine
• Immunology
• Intensive care unit (ICU) patient outcomes

Background:

• Advances in critical care have reduced in-hospital mortality for multiple organ failure.
• This success has led to an increased incidence of chronic critical illness (CCI).
• Patients with CCI often experience prolonged ICU stays, high resource use, and poor long-term prognoses.

Purpose of the Study:

• To identify and describe a novel clinical phenotype within the chronic critical illness population.
• To propose the "persistent inflammation, immunosuppression, and catabolism syndrome" (PIICS) as a distinct condition.
• To explore the underlying mechanisms contributing to this proposed syndrome.

Main Methods:

• Review of existing literature and clinical data on chronic critical illness patients.
• Analysis of immunological and metabolic profiles in subsets of critically ill patients.
• Identification of common pathological pathways and contributing factors.

Main Results:

• A significant subset of chronic critical illness patients exhibit a shared phenotype characterized by persistent inflammation, immunosuppression, and catabolism.
• Myelodysplasia, expansion of myeloid-derived suppressor cells, and immune suppression are implicated.
• Protein catabolism and malnutrition are identified as major contributors to this syndrome.

Conclusions:

• The persistent inflammation, immunosuppression, and catabolism syndrome (PIICS) represents a distinct and emerging phenotype in chronic critical illness.
• Understanding PIICS is crucial for improving the care of critically ill patients with poor prognoses.
• Novel, multimodality treatment strategies are necessary to effectively manage patients with PIICS.