Persistent inflammation, immunosuppression and catabolism syndrome (PICS) in critically ill children is associated with clinical outcomes: a prospective longitudinal study

Charting the course for improved outcomes in chronic critical illness: therapeutic strategies for persistent inflammation, immunosuppression, and catabolism syndrome (PICS)

Enhanced critical care delivery has led to improved survival rates in critically ill patients, yet sepsis remains a leading cause of multiorgan failure with variable recovery outcomes. Chronic critical illness, characterised by prolonged ICU stays and persistent end-organ dysfunction, presents a significant challenge in patient management, often requiring multifaceted interventions. Recent research, highlighted in a comprehensive review in the British Journal of Anaesthesia, focuses on addressing the pathophysiological drivers of chronic critical illness, such as persistent inflammation, immunosuppression, and catabolism, through targeted therapeutic strategies including immunomodulation, muscle wasting prevention, nutritional support, and microbiome modulation. Although promising avenues exist, challenges remain in patient heterogeneity, treatment timing, and the need for multimodal approaches.

Pediatric Persistent Inflammation, Immunosuppression, and Catabolism Syndrome Prevalence in Sepsis-Related Mortalities: A 23-Year Institutional History

BACKGROUND

Delayed mortality in sepsis often is linked to a lack of resolution in the inflammatory cascade termed persistent inflammation, immunosuppression, and catabolism syndrome (PICS). Limited research exists on PICS in pediatric patients with sepsis.

RESEARCH QUESTION

What is the prevalence of pediatric PICS (pPICS) in patients who died of sepsis-related causes and what associated pathogen profiles and comorbidities did they have compared with those patients without pPICS who died from sepsis?

STUDY DESIGN AND METHODS

A retrospective study of a single institution using a de-identified database from 1997 through 2020 for all patients aged 21 years or younger who died of culture-positive sepsis from a known source and who had laboratory data available were evaluated for the presence of pPICS.

RESULTS

Among records extracted from the institutional database, 557 patients had culture-positive sepsis, with 262 patients having pPICS (47%). Patients with pPICS were more likely to have underlying hematologic or oncologic disease or cardiac disease. In addition, patients who had pPICS showed increased odds of associated fungal infection compared with those patients who did not (OR, 2.69; 95% CI, 1.59-4.61; P < .001). When assessing laboratory criteria, having a sustained absolute lymphocyte count of < 1.0 × 103/μL was most closely associated with having pPICS compared with other laboratory parameters. Finally, the results of multivariate logistic regression analysis indicated that patients with pPICS were more common in the cardiac ICU, as opposed to the PICU (OR, 3.43; CI, 1.57-7.64; P = .002).

INTERPRETATION

Pediatric patients who died of a sepsis-related cause have a pPICS phenotype nearly one-half of the time. These patients are more likely to be in the cardiac ICU than the pediatric ICU and have associated fungal infections. Special attention should be directed toward this population in future research.

Defining Pediatric Chronic Critical Illness: A Scoping Review

OBJECTIVES

Children with chronic critical illness (CCI) are hypothesized to be a high-risk patient population with persistent multiple organ dysfunction and functional morbidities resulting in recurrent or prolonged critical care; however, it is unclear how CCI should be defined. The aim of this scoping review was to evaluate the existing literature for case definitions of pediatric CCI and case definitions of prolonged PICU admission and to explore the methodologies used to derive these definitions.

DATA SOURCES

Four electronic databases (Ovid Medline, Embase, CINAHL, and Web of Science) from inception to March 3, 2021.

STUDY SELECTION

We included studies that provided a specific case definition for CCI or prolonged PICU admission. Crowdsourcing was used to screen citations independently and in duplicate. A machine-learning algorithm was developed and validated using 6,284 citations assessed in duplicate by trained crowd reviewers. A hybrid of crowdsourcing and machine-learning methods was used to complete the remaining citation screening.

DATA EXTRACTION

We extracted details of case definitions, study demographics, participant characteristics, and outcomes assessed.

DATA SYNTHESIS

Sixty-seven studies were included. Twelve studies (18%) provided a definition for CCI that included concepts of PICU length of stay (n = 12), medical complexity or chronic conditions (n = 9), recurrent admissions (n = 9), technology dependence (n = 5), and uncertain prognosis (n = 1). Definitions were commonly referenced from another source (n = 6) or opinion-based (n = 5). The remaining 55 studies (82%) provided a definition for prolonged PICU admission, most frequently greater than or equal to 14 (n = 11) or greater than or equal to 28 days (n = 10). Most of these definitions were derived by investigator opinion (n = 24) or statistical method (n = 18).

CONCLUSIONS

Pediatric CCI has been variably defined with regard to the concepts of patient complexity and chronicity of critical illness. A consensus definition is needed to advance this emerging and important area of pediatric critical care research.

Case report: Temporal alterations in vascular function during the first 2 weeks of pediatric septic shock

INTRODUCTION

During sepsis and septic shock, the host's immune systems generate an overwhelming and often, detrimental, inflammatory response. Part of this response results in significant alterations in blood flow and vasomotor tone regulated in part by endothelial and vascular smooth muscle cells. Here, we report on a series of 3 pediatric patients for whom vascular response was assessed by laser doppler perfusion coupled to iontophoresis over the first 2 weeks after hospitalization for septic shock to demonstrate similarities and dissimilarities in the vascular response.

CASE PRESENTATIONS

A 12-year-old male with a history of Burkitt's Lymphoma, a 21-year-old male with congenital porencephaly and epilepsy, and a 7-year-old male with no significant past medical history all were admitted to a tertiary care children's hospital with a diagnosis of septic shock requiring vasoactive infusions to maintain mean arterial blood pressure. Non-invasive laser doppler perfusion coupled with iontophoresis of either acetylcholine (endothelial-dependent response) or sodium nitroprusside (endothelial-independent response) was performed on hospital days 1, 3, 7, and 14. Variability and heterogeneity were demonstrated by the temporal assessments of the vascular response to sodium nitroprusside, but all three patients showed significant similarity in the temporal responsiveness to acetylcholine.

CONCLUSION

Assessment of baseline and temporal responsiveness to endothelial-dependent vascular reactivity may provide a predictable timeline to the resolution of pediatric septic shock.

Is Undernutrition Associated With Deterioration of Outcomes in the Pediatric Intensive Care Unit (PICU): Systematic and Meta-Analysis Review

BACKGROUND AND AIM

Undernutrition (UN) may negatively impact clinical outcomes for hospitalized patients. The relationship between UN status at pediatric intensive care unit (PICU) admission and clinical outcomes is still not well-reported. This systematic meta-analysis review evaluated the impact of UN at admission to PICU on clinical outcomes, including mortality incidence, length of stay (LOS), and the need for and length of time on mechanical ventilation (MV).

METHODS

A search was conducted using relevant and multi-medical databases from inception until January 2022. We considered studies that examined the link between UN at PICU admission and clinical outcomes in patients aged 18 years or younger. Pooled risk difference estimates for the PICU outcomes were calculated using a random-effects model.

RESULT

There were a total of 10,638 patients included in 17 observational studies; 8,044 (75.61%) and 2,594 (24.38%) patients, respectively, were normal-nourished (NN) and undernourished (UN). In comparison to NN patients, UN patients had a slightly higher risk of mortality (RD = 0.02, P = 0.05), MV usage (RD = 0.05, P = 0.02), and PICU LOS (RD = 0.07, P = 0.007). While the duration of MV was significantly longer in UN than in NN (RD = 0.13, P < 0.0001). Sensitivity analysis of UN classification cohorts with a z-score < -2 or in the 5%, patetints age up to 18 years, and mixed diagnose for PICU admission demonstrated a 6-fold increase in the probability of PICU LOS in UN patients compared to NN patients (RD = 0.06, 95% CI = 0.01, 0.12). UN patients have a higher risk of MV usage RD = 0.07, 95% CI = 0.00, 0.14) in studies involving cohorts with a mixed primary diagnosis for PICU admission.

CONCLUSION

In PICU, UN is linked to mortality incidence, longer PICU stay, MV usage, and duration on MV. The primary diagnosis for PICU admission may also influence clinical outcomes. Determining the prevalence of UN in hospitalized patients, as well as the subgroups of patients diagnosed at the time of admission, requires more research. This may help explain the relationship between nutritional status and clinical outcomes in PICU patients.

Cystatin C and/or creatinine-based estimated glomerular filtration rate for prediction of vancomycin clearance in long-stay critically ill patients with persistent inflammation, immunosuppression and catabolism syndrome (PICS): a population pharmacokinetics analysis

Persistent inflammation, immunosuppression and catabolism syndrome (PICS) in critically ill patients are associated with unreliable creatinine (Cr)-based estimated glomerular filtration rate (eGFR) and alteration in vancomycin clearance (CL) due to ongoing muscle wasting and renal dysfunction (RD). Currently, cystatin C (Cys) is of great interest for eGFR due to its muscle independence. Patients receiving intravenous vancomycin with trough concentration monitoring after intensive care unit stay ≥ 14 days were retrospectively enrolled. Those with C-reactive protein > 30.0 mg/L, lymphocytes count < 0.80 × 10⁹, albumin < 30 mg/L and weight loss > 10% were diagnosed with PICS. Impact of PICS on vancomycin trough achievement was analyzed. Plasma Cys and Cr levels with their eGFRs in RD were compared in patients with and without PICS. Furthermore, the performance of eGFRs in predicting vancomycin CL was quantificationally evaluated by population pharmacokinetics (PPK) analysis using the Phoenix NLME software. Of 69 enrolled patients, 32 (46.4%) were PICS. PICS was predictive of Cr-guided vancomycin supratherapeutic trough concentrations (OR = 5.26, P = 0.013). Significant elevation of Cys, not of Cr, was observed in patients with PICS suffering from RD (P = 0.022), causing substantial differences among eGFRs. Fifty-two and 17 patients were enrolled for the modeling group and validation group, respectively. A one-compartment PPK model with first-order elimination adequately described the data of 126 C_trough. Prediction of vancomycin CL with Cys and Cr-based eGFR (CKD-EPI_cys-cr) significantly reduced the interindividual variability of CL (from 75.6 to 28.5%). External validation with 34 C_trough showed the robustness and accuracy of this model. This study showed the negative impact of PICS on Cr-guided vancomycin trough achievement. PPK model with CKD-EPI_cys-cr can be used to optimize vancomycin dosage in patients with PICS.