The incidence of acute kidney injury (AKI) in the intensive care unit (ICU) has increased during the past decade due to increased acuity as well as increased recognition. Early epidemiology studies were confounded by erratic definitions of AKI until recent consensus guidelines (RIFLE and AKIN) standardized its definition. This paper discusses the incidence of AKI in the ICU with focuses on specific patient populations. The overall incidence of AKI in ICU patients ranges from 20% to 50% with lower incidence seen in elective surgical patients and higher incidence in sepsis patients. The incidence of contrast-induced AKI is less (11.5%–19% of all admissions) than seen in the ICU population at large. AKI represents a significant risk factor for mortality and can be associated with mortality greater than 50%.

Acute respiratory distress syndrome (ARDS) is an acute inflammatory condition with a dramatic increase in incidence since the beginning of the coronavirus disease 19 (COVID‐19) pandemic. Neutrophils play a vital role in the immunopathology of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection by triggering the formation of neutrophil extracellular traps (NETs), producing cytokines including interleukin‐8 (CXCL8), and mediating the recruitment of other immune cells to regulate processes such as acute and chronic inflammation, which can lead to ARDS. CXCL8 is involved in the recruitment, activation, and degranulation of neutrophils, and therefore contributes to inflammation amplification and severity of disease. Furthermore, activation of neutrophils also supports a prothrombotic phenotype, which may explain the development of immunothrombosis observed in COVID‐19 ARDS. This review aims to describe hyperinflammatory ARDS due to SARS‐CoV‐2 infection. In addition, we address the critical role of polymorphonuclear neutrophils, inflammatory cytokines, and the potential targeting of CXCL8 in treating the hyperinflammatory ARDS population.

Obstructive sleep apnea (OSA) is an independent risk factor for sudden cardiac death. The aim of this review was to study the relationship between OSA and ventricular arrhythmias. PubMed, Medline, and Cochrane databases were searched with MESH headings to find studies linking OSA and ventricular arrhythmias including ventricular ectopy, ventricular tachycardia (VT), and ventricular fibrillation (VF). Studies were graded by a scoring system, and an attempt was made to pool data. There were no matched cohort or case control studies to study the association between OSA and ventricular arrhythmias. Given data heterogeneity, pooling and meta-analysis of data were not possible. An attempt was made to judge the quality of evidence and present a systematic review. Patients with OSA were noted to have higher odds of ventricular ectopy, and were at a higher risk for ventricular arrhythmias. Associations included higher QTc dispersion and HR variability. We did not, however, find any clear evidence for a direct correlation between increased apnea hypopnea index and increased VT or VF. Pooling and meta-analysis of studies linking OSA and ventricular arrhythmias were not possible due to heterogeneity of data. In a systemic review of studies, patients with OSA were noted to have higher odds of ventricular ectopy and arrhythmias. A single study showed that CPAP may help lower arrhythmogenicity; however, it was unclear if CPAP lowered the risk of VT. Further research should focus on studying the association of OSA and causes of sudden cardiac death, including ventricular arrhythmias.

Asthma is a disease with distinct phenotypes that have implications for both prognosis and therapy. Epidemiologic studies have demonstrated an association between asthma and obesity. Further studies have shown that obese asthmatics have poor asthma control and more severe asthma. This obese-asthma group may represent a unique phenotype. The mechanisms behind poor asthma control in obese subjects remain unclear, but recent research has focused on adipokines and their effects on the airways as well as the role of oxidative stress. Both surgical and nonsurgical weight loss therapy have shown promising results with improvements in asthma control and decreased asthma severity. Comorbid conditions such as gastroesophageal reflux disease and obstructive sleep apnea may also have a role in poor asthma control in obese asthmatics. Further research is needed to define the mechanisms behind this phenotype which will guide the development of targeted therapies.