Insights from CTTACC: immune system reset by cellular therapies for chronic illness after trauma, infection, and burn.

BACKGROUND AIMS: In this paper, we present a review of several selected talks presented at the CTTACC conference (Cellular Therapies in Trauma and Critical Care) held in Scottsdale, AZ in May 2023. This conference review highlights the potential for cellular therapies to "reset" the dysregulated immune response and restore physiologic functions to normal. Improvements in medical care systems and technology have increasingly saved lives after major traumatic events. However, many of these patients have complicated post-traumatic sequelae, ranging from short-term multi-organ failure to chronic critical illness. METHODS/RESULTS: Patients with chronic critical illness have been found to have dysregulated immune responses. These abnormal and harmful immune responses persist for years after the initial insult and can potentially be mitigated by treatment with cellular therapies. CONCLUSIONS: The sessions emphasized the need for more research and clinical trials with cellular therapies for the treatment of a multitude of chronic illnesses: post-trauma, radiation injury, COVID-19, burns, traumatic brain injury (TBI) and other chronic infections.

Risk factors, biomarkers, and mechanisms for persistent inflammation, immunosuppression, and catabolism syndrome (PICS): a systematic review and meta-analysis.

INTRODUCTION: Persistent inflammation, immunosuppression, and catabolism syndrome (PICS) has been proposed as an endotype of chronic critical illness (CCI). The aim of this systematic review is to synthesise the available evidence of risk factors, biomarkers, and biological mechanisms underlying PICS. METHODS: MEDLINE, CENTRAL, and EMBASE were searched on June 2, 2023. Our population of interest was adult intensive care unit survivors. The exposure group was patients with PICS and the comparator group was patients with no PICS, CCI, or rapid recovery. Mean differences were pooled for each biomarker using a random effects DerSimonian-Laird method. Risk of bias assessment was done using the Newcastle-Ottawa Scale. RESULTS: Six papers were included. Five were single-centre retrospective cohort studies, and one was a prospective cohort study, with sample sizes ranging from 22 to 391 patients. Two studies showed an increased incidence of PICS with age, and two studies showed an association between PICS and Charlson Comorbidity Index scores. PICS was associated with requiring mechanical ventilation in four studies. Meta-analysis showed a 34.4 mg L-1 higher C-reactive protein (95% confidence interval [CI] 12.7-56.2 mg L-1; P<0.01), a 4.4 g L-1 lower albumin (95% CI 0.5-8.3 g L-1; P<0.01), and a 0.36×109 L-1 lower lymphocyte count (95% CI 0.25-0.47×109 L-1; P=0.01) in the PICS compared with the non-PICS group. There are a large variety of other potential biomarkers but limited validation studies. The overall quality of evidence is limited, and these results should be interpreted accordingly. CONCLUSIONS: While older patients and those with co-morbidities could be at greater risk for PICS, acquired risk factors, such as injury severity, are potentially more predictive of PICS than intrinsic patient characteristics. There are many potential biomarkers for PICS, but limited validation studies have been conducted. Persistent myeloid-derived suppressor cell expansion, the continual release of danger-associated molecular patterns and pathogen-associated molecular patterns propagating inflammation, and bioenergetic failure are all mechanisms underlying PICS that could offer potential for novel biomarkers and therapeutic interventions. CLINICAL TRIAL REGISTRATION: International Prospective Register of Systematic Reviews (PROSPERO; CRD42023427749).

Persistent inflammation, immunosuppression, and catabolism syndrome (PICS): a review of definitions, potential therapies, and research priorities.

Persistent Inflammation, Immunosuppression, and Catabolism Syndrome (PICS) is a clinical endotype of chronic critical illness. PICS consists of a self-perpetuating cycle of ongoing organ dysfunction, inflammation, and catabolism resulting in sarcopenia, immunosuppression leading to recurrent infections, metabolic derangements, and changes in bone marrow function. There is heterogeneity regarding the definition of PICS. Currently, there are no licensed treatments specifically for PICS. However, findings can be extrapolated from studies in other conditions with similar features to repurpose drugs, and in animal models. Drugs that can restore immune homeostasis by stimulating lymphocyte production could have potential efficacy. Another treatment could be modifying myeloid-derived suppressor cell (MDSC) activation after day 14 when they are immunosuppressive. Drugs such as interleukin (IL)-1 and IL-6 receptor antagonists might reduce persistent inflammation, although they need to be given at specific time points to avoid adverse effects. Antioxidants could treat the oxidative stress caused by mitochondrial dysfunction in PICS. Possible anti-catabolic agents include testosterone, oxandrolone, IGF-1 (insulin-like growth factor-1), bortezomib, and MURF1 (muscle RING-finger protein-1) inhibitors. Nutritional support strategies that could slow PICS progression include ketogenic feeding and probiotics. The field would benefit from a consensus definition of PICS using biologically based cut-off values. Future research should focus on expanding knowledge on underlying pathophysiological mechanisms of PICS to identify and validate other potential endotypes of chronic critical illness and subsequent treatable traits. There is unlikely to be a universal treatment for PICS, and a multimodal, timely, and personalised therapeutic strategy will be needed to improve outcomes for this growing cohort of patients.

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.

A prolonged intensive care unit stay defines a worse long-term prognosis - Insights from the critically ill mortality by age (Cimba) study.

BACKGROUND: Patients with critical illness often survive the intensive care unit (ICU) at a cost of prolonged length of stay (LOS) and slow recovery. This chronic critically ill disease may lead to long-term poor outcomes, especially in older or frail patients. OBJECTIVES: The main goal of this study was to address the characteristics and outcomes of patients with prolonged ICU LOS. Mainly, short- and long-term admissions were compared to identify risk factors for persistent critical illness and to characterise the impact on ICU, hospital, and long-term mortality. METHODS: Subanalysis of a retrospective, multicentric, observational study addressing the 2-year outcome of patients admitted to Portuguese ICUs (the Cimba study). Patients were segregated according to an ICU LOS of ≥14 days. RESULTS: Data from 37 118 patients were analysed, featuring a median ICU LOS of 4 days (percentile: 25-75 2-9), and a mortality of 16.1% in the ICU, 24.0% in the hospital, and 38.7% after 2 years. A total of 5334 patients (14.4%) had an ICU LOS of ≥14 days (corresponding to 48.9% of all ICU patients/days). Patients with prolonged LOS were more often younger (52.8% vs 46.4%, were ≤65 years of age , p < 0.001), although more severe (Simplified Acute Physiology Score II: 49.1 ± 16.9 vs 41.8 ± 19.5, p < 0.001), and had higher ICU and hospital mortality (18.3% vs 15.7%, and 31.2 vs 22.8%, respectively). Prolonged ICU LOS was linked to an increased risk of dying during the 2-year follow-up (adjusted Cox proportional hazard: 1.65, p < 0.001). CONCLUSION: Prolonged LOS is associated with a long-term impact on patient prognosis. More careful planning of care should incorporate these data.

Consequences of a stay in the intensive care unit and outpatient follow-up care for chronic critically ill patients: A retrospective data analysis.

BACKGROUND: Patients with chronic critical illness (CCI) represent a particularly vulnerable patient population with significant quality-of-life consequences and a need for follow-up care. Existing research on their quality-of-life trajectory and outpatient follow-up care is limited. OBJECTIVES: The aim of this study was to (i) describe a quality improvement project focussing on patients with CCI in the Swiss setting; (ii) explain the consequences of an intensive care unit (ICU) stay for patients with CCI; and (iii) evaluate outpatient follow-up care for patients with CCI. METHODS: This retrospective descriptive mixed-methods longitudinal study used routine data from outpatient follow-up care between October 2018 and June 2022. The pre-ICU data were collected retrospectively for the week before ICU admission (baseline); prospectively at 3, 6, and 12 months after ICU discharge; and during an outpatient follow-up care at 6 months. Its main outcomes were health-related quality of life (HRQOL). Patients with CCI were defined as those having a ICU stay longer than 7 days. RESULTS: This study enrolled 227 patients with outpatient follow-up care, but only 77 were analysed at all four timepoints. Their EuroQol five-dimension five-level questionnaire-Visual Analogue Scale scores ranged from 0 to 100, with a median of 85 (interquartile range = 0-100) and a mean of 77.2 (standard deviation ± 23.52) before their ICU stay. Their scores had almost returned to the baseline 12 months after their ICU stay. While some reported existing restrictions in the individual HRQOL dimensions before their ICU stay, patients and their families appreciated the outpatient follow-up care including an ICU visit. CONCLUSION: Patients with CCI have different HRQOL trajectories over time. Patients with CCI can have a good HRQOL despite their impairments; however, the HRQOL trajectories of many patients remain unclear. The focus must be on identifying the illness trajectories and on measuring and maintaining their long-term HRQOL.

A Snapshot of Chronic Critical Illness in Pediatric Intensive Care Units.

Children with chronic critical illness (CCI) represent the sickest subgroup of children with medical complexity. In this article, we applied a proposed definition of pediatric CCI to assess point prevalence in medical, cardiovascular, and combined pediatric intensive care units (PICUs), screening all patients admitted to six academic medical centers in the United States on May 17, 2017, for pediatric CCI (PCCI) eligibility. We gathered descriptive data to understand medical complexity and resource needs of children with PCCI in PICUs including data regarding hospitalization characteristics, previous admissions, medical technology, and chronic multiorgan dysfunction. Descriptive statistics were used to characterize the study population and hospital data. The study cohort was divided between PICU-prolonged (stay > 14 days) and PICU-exposed (any time in PICU); comparative analyses were conducted. On the study day, 185 children met inclusion criteria, 66 (36%) PICU-prolonged and 119 (64%) PICU-exposed. Nearly all had home medical technology and most ( n = 152; 82%) required mechanical ventilation in the PICU. The PICU-exposed cohort mirrored the PICU-prolonged with a few exceptions as follows: they were older, had fewer procedures and surgeries, and had more recurrent hospitalizations. Most ( n = 44; 66%) of the PICU-prolonged cohort had never been discharged home. Children with PCCI were a sizable proportion of the unit census on the study day. We found that children with PCCI are a prevalent population in PICUs. Dividing the cohorts between PICU-prolonged and PICU-exposed helps to better understand the care needs of the PCCI population. Identifying and studying PCCI, including variables relevant to PICU-prolonged and PICU-exposed, could inform changes to PICU care models and training programs to better enable PICUs to meet their unique needs.

Persistent Inflammation, Immunosuppression, and Catabolism Syndrome in Pediatric Populations: A Brief Perspective.

Surviving near-lethal insults, such as sepsis, trauma, and major surgery is more common due to advances in medical care. The decline in mortality has unmasked a population of chronic critically ill patients, many with the pathological immunophenotype known as Persistent inflammation, Immunosuppression, and Catabolism Syndrome (PICS). Though initially described in adults, many critically ill children exhibit the hallmarks of PICS, including lymphopenia, hyperinflammation, and evidence of ongoing somatic protein catabolism. These patients are plagued with recurrent infections and suffer worse outcomes. There remains a need to understand the pathophysiology underlying this condition to elucidate potential therapies and develop interventions. This perspective provides the most current update of PICS within the pediatric population.

Where do families turn? Ethical dilemmas in the care of chronically critically Ill children.

Advancements in early diagnosis and novel treatments for children with complex and chronic needs have improved their chances of survival. But many survive with complex medical needs and ongoing medical management in the setting of prognostic uncertainty. Their medical care relies more and more on preference-sensitive decisions, requiring medical team and family engagement in ethically challenging situations. Many families are unprepared as they face these ethical challenges and struggle to access relevant ethical resources. In this paper, Timmy's narrative, situated in the context of what is known about ethical challenges in the care of children with chronic critical illness (CCI), serves as a case study of the gap in available ethical resources to guide families in their approach to difficult decision making for children with significant medical complexity and CCI. Our author group, inclusive of parents of children with complex medical needs and medical professionals, identifies domains of ethical challenges facing families of children with CCI and we highlight the development of family/caregiver-oriented ethics resources as an essential expansion of pediatric bioethics.

Advances in nutritional metabolic therapy to impede the progression of critical illness.

With the advancement of medical care and the continuous improvement of organ support technologies, some critically ill patients survive the acute phase of their illness but still experience persistent organ dysfunction, necessitating long-term reliance on intensive care and organ support, known as chronic critical illness. Chronic critical illness is characterized by prolonged hospital stays, high mortality rates, and significant resource consumption. Patients with chronic critical illness often suffer from malnutrition, compromised immune function, and poor baseline health, which, combined with factors like shock or trauma, can lead to intestinal mucosal damage. Therefore, effective nutritional intervention for patients with chronic critical illness remains a key research focus. Nutritional therapy has emerged as one of the essential components of the overall treatment strategy for chronic critical illness. This paper aims to provide a comprehensive review of the latest research progress in nutritional support therapy for patients with chronic critical illness.

The Tri-Steps Model of Critical Conditions in Intensive Care: Introducing a New Paradigm for Chronic Critical Illness.

Background: The prevailing model for understanding chronic critical illness is a biphasic model, suggesting phases of acute and chronic critical conditions. A major challenge within this model is the difficulty in determining the timing of the process chronicity. It is likely that the triad of symptoms (inflammation, catabolism, and immunosuppression [ICIS]) could be associated with this particular point. We aimed to explore the impact of the symptom triad (inflammation, catabolism, immunosuppression) on the outcomes of patients hospitalized in intensive care units (ICUs). Methods: The eICU-CRD database with 200,859 ICU admissions was analyzed. Adult patients with the ICIS triad, identified by elevated CRP (>20 mg/L), reduced albumin (<30 g/L), and low lymphocyte counts (<0.8 × 109/L), were included. The cumulative risk of developing ICIS was assessed using the Nelson-Aalen estimator. Results: This retrospective cohort study included 894 patients (485 males, 54%), with 60 (6.7%) developing ICIS. The cumulative risk of ICIS by day 21 was 22.5%, with incidence peaks on days 2-3 and 10-12 after ICU admission. Patients with the ICIS triad had a 2.5-fold higher mortality risk (p = 0.009) and double the likelihood of using vasopressors (p = 0.008). The triad onset day did not significantly affect mortality (p = 0.104). Patients with ICIS also experienced extended hospital (p = 0.041) and ICU stays (p < 0.001). Conclusions: The symptom triad (inflammation, catabolism, immunosuppression) during hospitalization increases mortality risk by 2.5 times (p = 0.009) and reflects the chronicity of the critical condition. Identifying two incidence peaks allows the proposal of a new Tri-steps model of chronic critical illness with acute, extended, and chronic phases.

Prolonged Mechanical Ventilation, Weaning, and the Role of Tracheostomy.

Depending on the definitional criteria used, approximately 5% to 10% of critical adults will require prolonged mechanical ventilation with longer-term outcomes that are worse than those ventilated for a shorter duration. Outcomes are affected by patient characteristics before critical illness and its severity but also by organizational characteristics and care models. Definitive trials of interventions to inform care activities, such as ventilator weaning, upper airway management, rehabilitation, and nutrition specific to the prolonged mechanical ventilation patient population, are lacking. A structured and individualized approach developed by the multiprofessional team in discussion with the patient and their family is warranted.

Immunometabolic features of natural killer cells are associated with infection outcomes in critical illness.

Immunosuppression increases the risk of nosocomial infection in patients with chronic critical illness. This exploratory study aimed to determine the immunometabolic signature associated with nosocomial infection during chronic critical illness. We prospectively recruited patients who were admitted to the respiratory care center and who had received mechanical ventilator support for more than 10 days in the intensive care unit. The study subjects were followed for the occurrence of nosocomial infection until 6 weeks after admission, hospital discharge, or death. The cytokine levels in the plasma samples were measured. Single-cell immunometabolic regulome profiling by mass cytometry, which analyzed 16 metabolic regulators in 21 immune subsets, was performed to identify immunometabolic features associated with the risk of nosocomial infection. During the study period, 37 patients were enrolled, and 16 patients (43.2%) developed nosocomial infection. Unsupervised immunologic clustering using multidimensional scaling and logistic regression analyses revealed that expression of nuclear respiratory factor 1 (NRF1) and carnitine palmitoyltransferase 1a (CPT1a), key regulators of mitochondrial biogenesis and fatty acid transport, respectively, in natural killer (NK) cells was significantly associated with nosocomial infection. Downregulated NRF1 and upregulated CPT1a were found in all subsets of NK cells from patients who developed a nosocomial infection. The risk of nosocomial infection is significantly correlated with the predictive score developed by selecting NK cell-specific features using an elastic net algorithm. Findings were further examined in an independent cohort of COVID-19-infected patients, and the results confirm that COVID-19-related mortality is significantly associated with mitochondria biogenesis and fatty acid oxidation pathways in NK cells. In conclusion, this study uncovers that NK cell-specific immunometabolic features are significantly associated with the occurrence and fatal outcomes of infection in critically ill population, and provides mechanistic insights into NK cell-specific immunity against microbial invasion in critical illness.

Achieving Goals of Care Decisions in Chronic Critical Illness: A Multi-Institutional Qualitative Study.

BACKGROUND: Physicians, patients, and families alike perceive a need to improve how goals of care (GOC) decisions occur in chronic critical illness (CCI), but little is currently known about this decision-making process. RESEARCH QUESTION: How do intensivists from various health systems facilitate decision-making about GOC for patients with CCI? What are barriers to, and facilitators of, this decision-making process? STUDY DESIGN AND METHODS: We conducted semistructured interviews with a purposeful sample of intensivists from the United States and Canada using a mental models approach adapted from decision science. We analyzed transcripts inductively using qualitative description. RESULTS: We interviewed 29 intensivists from six institutions. Participants across all sites described GOC decision-making in CCI as a complex, longitudinal, and iterative process that involved substantial preparatory work, numerous stakeholders, and multiple family meetings. Intensivists required considerable time to collect information on prior events and conversations, and to arrive at a prognostic consensus with other involved physicians prior to meeting with families. Many intensivists stressed the importance of scheduling multiple family meetings to build trust and relationships prior to explicitly discussing GOC. Physician-identified barriers to GOC decision-making included 1-week staffing models, limited time and cognitive bandwidth, difficulty eliciting patient values, and interpersonal challenges with care team members or families. Potential facilitators included scheduled family meetings at regular intervals, greater interprofessional involvement in decisions, and consistent messaging from care team members. INTERPRETATION: Intensivists described a complex time- and labor-intensive group process to achieve GOC decision-making in CCI. System-level interventions that improve how information is shared between physicians and decrease logistical and relational barriers to timely and consistent communication are key to improving GOC decision-making in CCI.

The post-septic peripheral myeloid compartment reveals unexpected diversity in myeloid-derived suppressor cells.

Introduction: Sepsis engenders distinct host immunologic changes that include the expansion of myeloid-derived suppressor cells (MDSCs). These cells play a physiologic role in tempering acute inflammatory responses but can persist in patients who develop chronic critical illness. Methods: Cellular Indexing of Transcriptomes and Epitopes by Sequencing and transcriptomic analysis are used to describe MDSC subpopulations based on differential gene expression, RNA velocities, and biologic process clustering. Results: We identify a unique lineage and differentiation pathway for MDSCs after sepsis and describe a novel MDSC subpopulation. Additionally, we report that the heterogeneous response of the myeloid compartment of blood to sepsis is dependent on clinical outcome. Discussion: The origins and lineage of these MDSC subpopulations were previously assumed to be discrete and unidirectional; however, these cells exhibit a dynamic phenotype with considerable plasticity.

Mental health sequelae in survivors of cardiogenic shock complicating myocardial infarction. A population-based cohort study.

PURPOSE: Cardiogenic shock secondary to acute myocardial infarction (AMI-CS) is associated with substantial short- and long-term morbidity and mortality. However, there are limited data on mental health sequelae that survivors experience following discharge. METHODS: We conducted a retrospective, population-based cohort study in Ontario, Canada of critically ill adult (≥ 18 years) survivors of AMI-CS, admitted to hospital between April 1, 2009 and March 31, 2019. We compared these patients to AMI survivors without shock. We captured outcome data using linked health administrative databases. The primary outcome was a new mental health diagnosis (a composite of mood, anxiety, or related disorders; schizophrenia/psychotic disorders; and other mental health disorders) following hospital discharge. We secondarily evaluated incidence of deliberate self-harm and death by suicide. We compared patients using overlap propensity score-weighted, cause-specific proportional hazard models. RESULTS: We included 7812 consecutive survivors of AMI-CS, from 135 centers. Mean age was 68.4 (standard deviation (SD) 12.2) years, and 70.3% were male. Median follow-up time was 767 days (interquartile range (IQR) 225-1682). Incidence of new mental health diagnosis among AMI-CS survivors was 109.6 per 1,000 person-years (95% confidence interval (CI) 105.4-113.9), compared with 103.8 per 1000 person-years (95% CI 102.5-105.2) among AMI survivors without shock. After propensity score adjustment, there was no difference in the risk of new mental health diagnoses following discharge [hazard ratio (HR) 0.99 (95% CI 0.94-1.03)]. Factors associated with new mental health diagnoses following AMI-CS included female sex, pre-existing mental health diagnoses, and discharge to a long-term hospital or rehabilitation institute. CONCLUSION: Survivors of AMI-CS experience substantial mental health morbidity following discharge. Risk of new mental health diagnoses was comparable between survivors of AMI with and without shock. Future research on interventions to mitigate psychiatric sequelae after AMI-CS is warranted.

Características epidemiológicas de los pacientes con enfermedad crítica crónica / Epidemiological characteristics of patients with chronic critical illness

Resumen ANTECEDENTES: la población de pacientes que requiere cuidados intensivos por tiempo prologado se ha incrementado en las últimas décadas dando lugar a una nueva población de pacientes con enfermedad crítica crónica. OBJETIVO: describir las características epidemiológicas de los pacientes con enfermedad crítica crónica atendidos en el Hospital Regional de Alta Especialidad de Oaxaca. MATERIAL Y MÉTODO: estudio ambispectivo, observacional y descriptivo que incluyó los pacientes ingresados entre el 1 de enero de 2012 al 31 de diciembre de 2015. Se definió a los pacientes con enfermedad crítica crónica como aquéllos con ventilación mecánica prolongada definida como más de 21 días de ventilación mecánica por más de 6 horas al día. Los pacientes fueron seguidos hasta su egreso hospitalario o defunción. RESULTADOS: se incluyeron 284 pacientes, la incidencia de enfermedad crítica crónica fue de 10%. En los pacientes con enfermedad crítica crónica la escala de APACHE II fue de 19.4±9.7 y sin enfermedad crítica crónica fue de 15.94±8.6 (p=0.044), mientras que la escala SOFA en los pacientes con y sin enfermedad crítica crónica fue de 8.7±2.6 y 7.01±4.4, respectivamente (p=0.007). La media de días de estancia en la unidad de cuidados intensivos (UCI) en los pacientes con y sin enfermedad crítica crónica fue de 17.1±9.2 y 8±4.8, respectivamente (p=0.0000). Los días de estancia hospitalaria fueron 45.9±19.7 y 18.3±12.4 en los pacientes con y sin enfermedad crítica crónica, respectivamente (p=0.0000). La mortalidad en la UCI fue de 18 y 28% en los pacientes con y sin enfermedad crítica crónica, respectivamente (p=0.0000). La mortalidad hospitalaria fue de 50 y 16% en los pacientes con y sin enfermedad crítica crónica, respectivamente (p=0.0000). Egresaron del hospital 32 y 56% de los pacientes con y sin enfermedad crítica crónica, respectivamente (p=0.0000). CONCLUSIONES: la incidencia de enfermedad crítica crónica en nuestro estudio fue similar a la reportada en la bibliografía. La severidad de la enfermedad aguda al ingreso de acuerdo con las escalas SOFA y APACHE se relaciona con la aparición de enfermedad crítica crónica. Los pacientes con enfermedad crítica crónica tuvieron mayor estancia en la UCI, mayores días de sedación, así como mayor estancia y mortalidad hospitalarias.

Abstract BACKGROUND: Population of patients requiring intensive care for prolonged time has increased in recent decades resulting in a new population of patients with chronic critical illness (CCI). OBJECTIVE: To describe the epidemiologic characteristics of patients with chronic critical illness assisted at Regional Hospital of High Specialty of Oaxaca, Mexico. MATERIAL AND METHOD: A retrospective, prospective, observa tional and descriptive study included patients admitted from January 1st, 2012 to December 31st, 2015. Patients with CCI were defined as those with prolonged mechanical ventilation defined as ≥21 days of ventilation for ≥6 hours/day. Patients were followed until hospital discharge or death. RESULTS: 284 patients were included; the incidence of CCI was 10%. In patients with CCI the APACHE II score was 19.4±9.7 and without CCI was 15.94±8.6 (p=0.044), while the SOFA scale in patients with CCI was 8.7±2.6 and without CCI 7.01±4.4 (p=0.007). Days of ICU stay were 17.1±9.2 for patients with CCI and 8±4.8 without CCI (p=0.0000). Days of hospital stay were 45.9±19.7 in patients with CCI and 18.3±12.4 in patients without CCI (p=0.0000). ICU mortality was 18% in patients with CCI and 28% in patients without CCI (p=0.0000). The hospital mortality was 50% in patients with CCI and 16% in patients without CCI (p=0.0000). Discharged from hospital were 32% of patients with CCI and 56% of patients without CCI (p=0.0000). CONCLUSIONS: The incidence of CCI in our study was similar to that reported in the literature. Severity of acute disease income according to APACHE and SOFA scales was related to the development of CCI. Patients with chronic critical illness had higher ICU stay, more days sedation, longer hospital stays and increased hospital mortality.