Continuous Glucose Monitoring in the Intensive Care Unit: A Multicenter, Retrospective Hospital-Based Analysis

Background: There is limited experience with continuous glucose monitoring (CGM) in intensive care units (ICUs). This study examined CGM accuracy and changes during hemodynamic instability in ICU patients with COVID-19. Methods: We pooled data from three ICUs using CGM within a hybrid protocol combining point-of-care (POC) blood glucose testing with intermittent nonadjunctive CGM use. We compared sensor-meter agreement during lowest oxygen saturation, arterial partial pressure of oxygen (PaO₂), pH, or mean arterial pressure (MAP). Linear mixed models (LMM) were used to estimate the effects of clinical condition on estimates of sensor accuracy. Result: Of 169 patients, >80% had a history of diabetes, mean age was 61 ± 12 years, and 82%, 93%, and 62% received corticosteroids, mechanical ventilation and vasopressors respectively. The median percent CGM time in range (TIR, 70-180 mg/dL) was 72% (64.9-81.4), 70% (54.0-76.9), and 46% (26.6-68.5) for hospitals A, B, and C. Median time below 70 mg/dL was <0.1% for all hospitals. The absolute relative difference between CGM and POC pairs did not correlate with the lowest PaO₂, oxygen saturation, pH, or mean arterial pressure. In LMM adjusting for within subject and between subject variability, patients on dialysis had higher mean absolute relative difference (MARD, [coefficient = 2.39, P = .05]), while patients on mechanical ventilation had lower MARD ventilation (coefficient = −4.33, P = .05). Of the 6783 pairs 97.3% fell within Clare zones A and B. Conclusion: These preliminary findings suggest CGM use does not appear to be significantly affected during critical illness. Confirmatory accuracy studies are needed.