Clinical trial NCT06964997: Anisocoria in the Intensive Care Unit (AICU Study)
Official title: Anisocoria in the ICU (AICU Study): Diagnostic Implications and Clinical Outcomes
Study type: OBSERVATIONAL
Overall status: ACTIVE_NOT_RECRUITING
Conditions: Anisocoria
Keywords: Pupillary abnormality
Intensive care unit
Lead sponsor: University Hospital, Basel, Switzerland
Sponsor class: OTHER
First posted: 2025-05-11
Enrollment: 920
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: RETROSPECTIVE
Sampling method: PROBABILITY_SAMPLE
Study population: Adult patients (i.e., patients ≥18 years of age) with a reported incident of pupillary abnormality (either anisocoria or non-normal pupillary reactivity) in the intensive care unit at the University Hospital Basel between 2013-2024.

Brief summary: This retrospective single-center cohort study aims to determine the prevalence of acute "new onset" pupillary abnormalities in adult intensive care unit patients, assess their clinical impact, identify the contexts leading to treatment changes, and evaluate their prognostic implications.

Detailed description: Assessment of the pupil symmetry and reactivity to light are important parts of the neurological evaluation of critically ill patients in intensive care units (ICUs). Anisocoria, a condition where the pupils are unequal in size, can be found in up to 60% of patients with acute neurologic injuries. It may indicate serious underlying issues like traumatic brain injury, cerebrovascular accidents, brain tumors or viral encephalitis. However, anisocoria or impaired pupillary reactivity can also be caused from less severe conditions, such as drug effects (e.g., ipratropium bromide),Horner's syndrome after central venous cannulation, or intoxications with substances like anticholinergics, opioids, and cannabinoids. Despite these well-known causes, there is limited data on the prevalence and clinical consequences of anisocoria in ICU patients.

New onset of pupillary abnormalities often requires immediate neurological evaluation and neuroimaging (computed tomography (CT) or magnetic resonance imaging (MRI)), but many of these scans may not reveal clinically relevant findings and could expose patients to unnecessary risks. This is particularly concerning as benign causes of pupillary abnormalities are common, while more serious conditions can sometimes be overlooked. Current studies do not fully address when CT or MRI scans are necessary, or when they provide no significant clinical benefit.

This retrospective single-center cohort study has four primary objectives:

1. to determine the prevalence of acute "new onset" pupillary abnormalities (anisocoria and/or impaired light-reactive pupillary response) in adult ICU patients.
2. to assess the clinical impact of these abnormalities, particularly in terms of the frequency of diagnostic tests like CT or MRI scans, and ophthalmologic and neurologic consultations.
3. to identify when pathological findings lead to treatment modifications
4. to evaluate the prognostic implications of these pupillary abnormalities on patient outcomes.

The results of this study may improve the understanding of acute pupillary abnormalities in ICU patients, helping to optimize diagnostic strategies, reduce unnecessary neuroimaging, and enhance patient safety and outcome prediction.

Eligibility criteria: Inclusion Criteria:

* Adult patients (i.e., patients ≥18 years of age)
* Reported incident of pupillary abnormality (either anisocoria or non-normal pupillary reactivity) in the intensive care unit at the University Hospital Basel between 2013-2024.

Exclusion Criteria:

* Patients younger than 18 years
* Patients with documented refusal of data use.

Primary outcomes:
measure: Acute prehospital management data
timeFrame: 2013-2024
measure: Duration of intensive care unit stay
timeFrame: 2013-2024
measure: Duration of hospital stay
timeFrame: 2013-2024
measure: Discharge destination
timeFrame: 2013-2024
measure: Date of incident
timeFrame: 2013-2024
measure: Characteristics of incident
timeFrame: 2013-2024
measure: Type of incident
timeFrame: 2013-2024
measure: Additional features of the incident
timeFrame: 2013-2024
measure: Patient characteristics
timeFrame: 2013-2024
measure: Consequences of the Incident
timeFrame: 2013-2024
measure: Comprehensive assessment of the neurological status based on validated clinical assessment
timeFrame: 2013-2024
measure: Comprehensive assessment of critical illness severity based on standardized scoring systems
timeFrame: 2013-2024
measure: Charlson Comorbidity Index
timeFrame: 2013-2024
measure: Laboratory parameters
timeFrame: 2013-2024
measure: Glasgow Outcome Score
timeFrame: 2013-2024
measure: Therapeutic intervention
timeFrame: 2013-2024
measure: Vital signs
timeFrame: 2013-2024
measure: Fluid balance data
timeFrame: 2013-2024
Secondary outcomes:
Other outcomes:
Locations:
city: Basel
country: Switzerland
facility: University Hospital Basel, Clinic for Intensive Care Medicine
state: Basel-Stadt
Study officials:
affiliation: University Hospital Basel, Clinic for Intensive Care Medicine
name: Raoul Sutter, Prof. Dr. med.
role: PRINCIPAL_INVESTIGATOR
References: