NCT06964997

Anisocoria in the Intensive Care Unit (AICU Study)

Anisocoria in the ICU (AICU Study): Diagnostic Implications and Clinical Outcomes

• Status: Active Not Recruiting
• Phase: —
• Study type: Observational
• Enrollment: 920 (actual)
• Sponsor: University Hospital, Basel, Switzerland · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

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.

Conditions

• Anisocoria

Timeline

• Start date: 2025-03-01
• Primary completion: 2025-12-01
• Completion: 2025-12-01
• First posted: 2025-05-11
• Last updated: 2025-05-11

Locations

1 site across 1 country: Switzerland