Insomnia Severity Following Intensive Care Unit Admission for Acute Respiratory Failure

Abstract Rationale: Patients admitted to the intensive care unit (ICU) frequently experience sleep disturbances. These disturbances can persist for months or even years following critical illness. The prevalence of sleep disturbances in acute respiratory failure (ARF) ICU survivors is less well understood. We sought to assess the relationship between clinical characteristics and sleep impairments in ICU survivors with ARF. Methods: This is a secondary analysis of the mobile critical care recovery program (mCCRP) clinical trial (n=466) which included patients 18 years or older admitted with ARF requiring invasive ventilation at 4 Indiana hospital ICUs. Demographics, comorbidities, and clinical characteristics were assessed using the electronic medical record during the index admission. Severity of illness was assessed using the Acute Physiology and Chronic Health Evaluation Score (APACHE-II). Sleep quality was assessed with the Insomnia Severity Index (ISI) at time of ICU discharge. ISI scores range from 0 to 28, with higher scores indicating worse insomnia. Patients who completed an ISI at discharge were included in this analysis. Logistic regression was performed to measure the relationship between demographic and clinical characteristics and odds of clinically significant insomnia. Results: A total of 362 patients were included in the analysis. The mean age of the cohort was 55.2 years (SD 14.0), 53.6% were female, 37.6% identified as Black, and 17.7% had pre-existing sleep disorders. The mean APACHE-II score was 24.8 (SD 8.8). Of the 362 patients, 31.2% reported clinical insomnia and 29.6% reported subthreshold insomnia. Patients with clinical insomnia had significantly higher rates of anxiety (47%) compared with those with subthreshold insomnia (31%) or no insomnia (25%, p=0.001). Participants with clinical insomnia also had higher rates of depression (53%) compared with those with subthreshold insomnia (31%) or no insomnia (25%, p=0.032). In a logistic regression model, patients with baseline anxiety had a significantly higher odds of developing clinical insomnia (OR 2.07, 95% CI 1.17 – 3.65). Additionally, patients a neurologic etiology of their ARF had a higher odds of developing clinical insomnia (OR 3.12, 95% CI 1.35 – 7.22). Conclusions: Insomnia was highly prevalent in our cohort of ICU survivors with ARF, with over 60% of patients experiencing some degree of sleep disturbance. Preexisting mental health diagnoses and a neurologic cause for acute respiratory failure were significant risk factors for post-ICU sleep dysfunction. Further study is needed to help determine interventions to reduce sleep disturbances both during ICU admission and after discharge.