High-flow nasal cannula for respiratory failure in adult patients

The high-flow nasal cannula (HFNC) has been recently used in several clinical settings for oxygenation in adults. In particular, the advantages of HFNC compared with low-flow oxygen systems or non-invasive ventilation include enhanced comfort, increased humidification of secretions to facilitate expectoration, washout of nasopharyngeal dead space to improve the efficiency of ventilation, provision of a small positive end-inspiratory pressure effect, and fixed and rapid delivery of an accurate fraction of inspired oxygen (FiO2) by minimizing the entrainment of room air. HFNC has been successfully used in critically ill patients with several conditions, such as hypoxemic respiratory failure, hypercapneic respiratory failure (exacerbation of chronic obstructive lung disease), post-extubation respiratory failure, pre-intubation oxygenation, and others. However, the indications are not absolute, and much of the proven benefit remains subjective and physiologic. This review discusses the practical application and clinical uses of HFNC in adults, including its unique respiratory physiologic effects, device settings, and clinical indications.

Association of natural light exposure and delirium according to the presence or absence of windows in the intensive care unit

Background: Patients in the intensive care unit (ICU) have increased risks of delirium, which is associated with worse outcomes. As pharmacologic treatments for delirium are ineffective, prevention is important. Nonpharmacologic preventive strategies include exposure to natural light and restoring circadian rhythm. We investigated the effect of exposure to natural light through windows on delirium in the ICU.Methods: This retrospective cohort study assessed all patients admitted to the medical ICU of a university-affiliated hospital between January and June 2020 for eligibility. The ICU included 12 isolation rooms, six with and six without windows. Patients with ICU stays of >48 hours were included and were divided into groups based on their admission to a single room with (window group) or without windows (windowless group). The primary outcome was the cumulative incidence of delirium. The secondary outcomes were the numbers of delirium- and mechanical ventilation-free days, ICU and hospital length of stay, and in-ICU and 28-day mortalities.Results: Of the 150 included patients (window group: 83 [55.3%]; windowless group: 67 [44.7%]), the cumulative incidence of delirium was significantly lower in the window group than in the windowless group (21.7% vs. 43.3%; relative risk, 1.996; 95% confidence interval [CI], 1.220–3.265). Other secondary outcomes did not differ between groups. Admission to a room with a window was independently associated with a decreased risk of delirium (adjusted odds ratio, 0.318; 95% CI, 0.125–0.805).Conclusions: Exposure to natural light through windows was associated with a lower incidence of delirium in the ICU.

COVID-19–induced acute kidney injury in critically ill patients: epidemiology, risk factors, and outcome

Background: The kidney represents a potential target for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Acute kidney injury (AKI) can occur through several mechanisms and includes intrinsic tissue injury by direct viral invasion. Clinical data about the clinical course of AKI are lacking. We aimed to investigate the proportion, risk factors, and prognosis of AKI in critical patients affected with coronavirus disease 2019 (COVID-19).Methods: A case/control study conducted in two intensive care units of a tertiary teaching hospital from September to December 2020.Results: Among 109 patients, 75 were male (69%), and the median age was 64 years (interquartile range [IQR], 57–71 years); 48 (44%) developed AKI within 4 days (IQR, 1–9). Of these 48 patients, 11 (23%), 9 (19%), and 28 (58%) were classified as stage 1, 2, and 3, respectively. Eight patients received renal replacement therapy. AKI patients were older and had more frequent sepsis, acute respiratory distress syndrome, and rhabdomyolysis; higher initial urea and creatinine; more marked inflammatory syndrome and hematological disorders; and required more frequent mechanical ventilation and vasopressors. An elevated level of D-dimers (odds ratio [OR], 12.83; 95% confidence interval [CI], 1.9–85) was an independent factor of AKI. Sepsis was near to significance (OR, 5.22; 95% CI, 0.94–28; P=0.058). Renal recovery was identified in three patients. AKI, hypoxemia with the ratio of the arterial partial pressure of oxygen and the inspiratory concentration of oxygen <70, and vasopressors were identified as mortality factors.Conclusions: AKI occurred in almost half the patients with critical COVID-19. A high level of D-dimers and sepsis contributed significantly to its development. AKI significantly worsened the prognosis in these patients.