Introduction

Intensive care unit-acquired weakness refers to clinically detectable muscle weakness that develops in critically ill patients, in whom no etiology other than the critical illness itself is identified [1,2]. The clinical impact of intensive care unit-acquired weakness is considerable and is associated with increased morbidity and mortality, prolonged hospital stays, and long-term disability [3,4,5,6]. However, the evidence supporting these estimates comes primarily from specific international contexts such as Europe, North America, and Asia [7,8,9], with little or no representation of Latin American studies in current systematic reviews and meta-analyses [9,10,11,12]. This disparity highlights the region’s marginal representation, which prevents us from accurately determining the volume, research characteristics, and true epidemiological profile of acquired weakness in the intensive care unit in Latin America.

The importance of addressing the Latin American context lies in the interaction between its biological and structural characteristics. The region exhibits complex demographic diversity, with significant genetic variations among countries such as Brazil, Mexico, and Peru [13]. This heterogeneity, combined with disparities in the organization and resources of healthcare systems, could influence both susceptibility to the disease and strategies for detecting and managing acquired weakness, particularly in the intensive care unit.

A preliminary review of the scientific literature shows that studies conducted in Latin America remain fragmented and address acquired weakness in the intensive care unit from various clinical and epidemiological perspectives. These studies have not been incorporated into systematic or overview reviews focused specifically on the region. Furthermore, the available evidence shows heterogeneity in clinical definitions, assessment methods, and reported outcomes. This lack of regional systematization hinders a comprehensive understanding of the phenomenon in the Latin American context. It also reinforces the need for a synthesis that enables the organization, description, and mapping of existing evidence, the identification of knowledge gaps, and the provision of an integrated view of the current state of research on acquired weakness in the intensive care unit.

Objective

This scoping review aims to describe and map the available evidence on the clinical and epidemiological characteristics of intensive care unit-acquired weakness among adults hospitalized in intensive care units in Latin America.

Methods

Design

A scoping review will be conducted following the methodology proposed by the Joanna Briggs Institute [14,15], reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA-ScR) guidelines for scoping reviews and their updated recommendations for protocols [16]. This methodological approach is appropriate by allowing a comprehensive overview of the available literature [17] without restricting study designs [18]. This is particularly relevant given the expected heterogeneity in assessment methods, clinical definitions, and outcomes used to describe intensive care unit-acquired weakness in the Latin American literature.

This protocol was prospectively registered in the International Platform of Registered Systematic Review and Meta-analysis Protocols (INPLASY), registration number: INPLASY202530135.

Review question

What are the clinical and epidemiological characteristics of adult patients with intensive care unit-acquired weakness in Latin America?

Eligibility criteria

The eligibility criteria were defined according to the Joanna Briggs Institute approach: population, concept, and context [14,15].

Population

Studies involving adults (18 years of age or older) with critical illness who are hospitalized in general, medical, surgical, coronary, or mixed intensive care units will be included. Studies that exclusively include patients in neurological intensive care units will be excluded, as well as those that include patients with neuromuscular, acute, or preexisting neurological conditions, such as Guillain-Barré syndrome, myasthenia gravis, stroke, intracranial trauma, or spinal cord injury. All of these conditions can independently affect the musculoskeletal system and complicate the diagnosis.

Concept

This review will consider studies that address intensive care unit-acquired weakness from a clinical and/or epidemiological perspective. Studies that diagnose this condition using validated clinical and functional methods, such as the Medical Research Council Sum Score (MRC-SS), handgrip strength testing, or other recognized methods, will be included. Studies reporting information on the prevalence and/or incidence of intensive care unit-acquired weakness, as well as the sociodemographic and clinical characteristics of patients—including age, gender, reason for admission to the intensive care unit, and associated comorbidities—will be eligible. Additionally, studies analyzing risk and/or protective factors related to the development of this specific weakness, as well as to the ICU hospitalization process—such as length of stay, days on invasive mechanical ventilation, complications, or pharmacological treatments administered—will be considered.

Context

Studies conducted in intensive care units from Latin American countries will be included, taking into account the region’s geographic, cultural, and health system diversity. There will be no restrictions based on the type of intensive care unit, provided that the study population was recruited entirely from Latin American countries. In the case of multicenter studies, they will be included only if all participating centers are located in Latin America or if data on Latin American patients are presented in a clearly differentiated manner. Studies conducted outside the region will be considered only if they explicitly analyzed patients from Latin America and report clearly separated results for this population.

Types of sources

This systematic review will consider various sources of information in order to identify the available evidence on intensive care unit-acquired weakness in Latin America. It will include observational primary studies such as cohort, case-control, and cross-sectional studies, as well as randomized clinical trials, case series, and case reports. Letters to the editor, editorials, and brief communications will also be considered, provided they contain primary data relevant to the review’s objectives. Additionally, gray literature—such as conference abstracts and academic theses—will be considered, provided it contains accessible information relevant to this review’s objectives. In cases where the same cohort is reported in multiple studies, the study with the most comprehensive report will be selected. On the other hand, studies with purely qualitative methodological approaches (as they do not provide epidemiological or clinical frequencies that can be extracted for the matrices) will be excluded, as well as purely methodological articles, study protocols without results, and systematic reviews, narrative reviews, or meta-analyses. However, the reference lists of these excluded reviews will be thoroughly scrutinized to identify potential additional primary studies.

Search strategy

The search strategy aims to identify published and unpublished studies related to acquired weakness in the intensive care unit in Latin America. Previously, a limited preliminary search was conducted in PubMed, LILACS (BVS), and EMBASE (ELSEVIER) to identify relevant articles and analyze the terms used in titles, abstracts, and subject headings. During this exploratory phase, key free-text terms (such as “ICUAW,” “polyneuropathy,” and “paresis”) and controlled vocabulary (such as the MeSH terms “Polyneuropathies” and “Muscle Weakness”) were identified. The results of this search allowed us to define and refine the controlled vocabulary, along with the free-text terms, to form the final search strategy proposed in this protocol. The terms identified in this phase are detailed in the supplementary file. In accordance with the Joanna Briggs Institute Manual, the search will be iterative, refined as we explore the literature or review cross-references. Based on this process, a comprehensive search strategy was developed, which will be applied and adapted to each information source. The search will be conducted in the following electronic databases: PubMed, LILACS (BVS), EMBASE (ELSEVIER), CINAHL (via the EBSCOhost platform), Scopus, and Web of Science. In addition, regional Latin American sources will be consulted, including SciELO, MedicLatina, and Referencia Latina—all accessible through the EBSCOhost platform—aiming to maximize retrieval of regional literature.

The search strategy will combine controlled terms (e.g., MeSH and Emtree) and free-text terms related to neuromuscular weakness, intensive care, and critical illness. To identify studies conducted in Latin America, country-specific geographic terms from the region will be included. Additionally, in databases that allow it (such as PubMed, EMBASE, Scopus, and others), filters by institutional affiliation will be applied based on the authors’ affiliation field to identify publications from Latin American institutions or those that include data clearly attributable to the region. Complementarily, a search for gray literature will be conducted on Google Scholar, focusing on the first 300 results [19]. Furthermore, the references of the selected articles will be manually reviewed to identify relevant publications.

A detailed description of the search strategies applied to the main databases—including the terms used, Boolean operators, search fields, and filters applied—is available in the repository (online supplementary file). No restrictions based on publication date will be applied. Studies published in Spanish, English, and Portuguese will be considered. This is because these are the predominant languages used for disseminating clinical research in Latin America and reflect the review team’s language proficiency. This ensures an accurate interpretation of the extracted data.

Study selection

Once the search is complete, all identified records will be compiled and uploaded to the Rayyan platform (Rayyan Systems Inc., Cambridge, MA, USA) for management and the selection process. Duplicate records will be identified and removed from the Rayyan platform. Subsequently, two independent reviewers (RG and RF) will evaluate the titles and abstracts of the identified studies to determine their eligibility based on the previously defined criteria. Studies that meet the criteria or for which there is reasonable doubt will be retrieved in full text for detailed evaluation. The evaluation of the full-text articles will also be conducted independently by two reviewers (RG and RF), using Rayyan as the platform for this process. Any discrepancies arising during the selection stages will be resolved through discussion and consensus, and a third reviewer (JN) will be consulted. The results of the selection process will be reported transparently in the final review and presented using a flow diagram in accordance with the PRISMA-ScR statement [20]. We anticipate the presence of conceptual duplicates, particularly when conference abstracts or gray literature correspond to subsequent full-text publications. In these cases, only the most complete or definitive version of the study will be retained.

Expected outcomes

It is expected that the results of this scoping review will provide a comprehensive characterization of intensive care unit-acquired weakness in Latin America, taking into account both its clinical and epidemiological dimensions. In particular, the results will allow us to describe the reported prevalence of this condition in the region, as well as the demographic and clinical characteristics of the studied populations, the contexts of hospitalization, and the diagnostic methods identified in clinical practice and regional research.

Furthermore, the results will enable us to identify and organize the available information on risk factors associated with intensive care unit-acquired weakness—where reported—as well as the management, prevention, or rehabilitation strategies described in the included studies. In this way, the review will provide a structured overview of how this condition is addressed across Latin American countries and different contexts, facilitating conceptual comparisons between studies, even when direct quantitative comparisons are not possible. However, it will allow us to discuss the information available from the rest of the world.

This review is expected to reveal significant heterogeneity in the reported outcomes, as well as both geographic and thematic knowledge gaps, reflected in the concentration of studies in certain countries, populations, or clinical approaches. Identifying these gaps will help define priority areas for future research, including observational studies, clinical interventions, and systematic reviews focused on specific subgroups or contexts.

From an applied perspective, the findings of this review will inform healthcare professionals, researchers, and decision-makers, contributing to a better understanding of the impact of weakness acquired in the intensive care unit within the Latin American context. This synthesis will serve as a conceptual and methodological foundation for planning assessment, prevention, and rehabilitation strategies tailored to local realities. Similarly, it will help strengthen the generation of regional evidence and its integration into the fields of intensive care and rehabilitation.