Investigation of the feasibility of using near-infrared spectroscopy (NIRS) to monitor microvascular function in critically ill patients.

This is a prospective observational study using non-invasive NIRS for microvascular monitoring in the ICU. The study involves no interventions above standard of care other than the application of the NIRS monitors.

NIRS will be applied to skeletal muscle and the brain longitudinally throughout ICU admission. Vital signs are extracted continuously from the ICU monitor and clinical data are recorded from patient records.

The broad goals of the study are:

1. Determine the feasibility of longitudinal NIRS monitoring in ICU patients
2. Determine the ability to derive patient-specific microvascular metrics using NIRS
3. Explore the relationship between microvascular metrics and ICU mortality

Inclusion Criteria:

• Admitted to ICU
• Receiving invasive mechanical ventilation

Exclusion Criteria:

• Body Mass Index >40
• More than 24 hours has elapsed since ICU admission
• Death is deemed to be imminent and inevitable during the next 24 hours
• Known allergy to the textile components of the device
• Significant clinical jaundice, ecchymosis
• COVID positive microbiological result
• The treating clinician believes that participation in the domain would not be in the best interests of the patient
• Consent declined from patient or authorized third party

Adults admitted to the ICU receiving invasive mechanical ventilation