Pathophysiology, mechanisms, and managements of tissue hypoxia.

Oxygen is needed to generate aerobic adenosine triphosphate and energy that is required to support vital cellular functions. Oxygen delivery (DO2) to the tissues is determined by convective and diffusive processes. The ability of the body to adjust oxygen extraction (ERO2) in response to changes in DO2 is crucial to maintain constant tissue oxygen consumption (VO2). The capability to increase ERO2 is the result of the regulation of the circulation and the effects of the simultaneous activation of both central and local factors. The endothelium plays a crucial role in matching tissue oxygen supply to demand in situations of acute drop in tissue oxygenation. Tissue oxygenation is adequate when tissue oxygen demand is met. When DO2 is severely compromised, a critical DO2 value is reached below which VO2 falls and becomes dependent on DO2, resulting in tissue hypoxia. The different mechanisms of tissue hypoxia are circulatory, anaemic, and hypoxic, characterised by a diminished DO2 but preserved capacity of increasing ERO2. Cytopathic hypoxia is another mechanism of tissue hypoxia that is due to impairment in mitochondrial respiration that can be observed in septic conditions with normal overall DO2. Sepsis induces microcirculatory alterations with decreased functional capillary density, increased number of stopped-flow capillaries, and marked heterogeneity between the areas with large intercapillary distance, resulting in impairment of the tissue to extract oxygen and to satisfy the increased tissue oxygen demand, leading to the development of tissue hypoxia. Different therapeutic approaches exist to increase DO2 and improve microcirculation, such as fluid therapy, transfusion, vasopressors, inotropes, and vasodilators. However, the effects of these agents on microcirculation are quite variable.

Thoracic surgery in United Arab Emirates.

The United Arab Emirates (UAE) has undergone a significant change in its population and economy in the last decades and in parallel its healthcare system has evolved rapidly to provide advanced, innovative and world-leading care. At the forefront of this revolution in healthcare is the development of a multidisciplinary multimodality thoracic service provision, offered at quaternary referral hospitals amalgamating academics, training, research and innovation. Previously, thoracic service care was limited to single providers at various public and private hospitals, usually performing lower complexity cases. Most complex thoracic cases were repatriated outside the UAE. This practice was replaced with the opening of Cleveland Clinic Abu Dhabi (CCAD), in 2015, which created a multidisciplinary thoracic program. This included the start of a mini-invasive surgical and lung transplantation program. Since that time other public and private hospitals have emerged providing care in a similar model. The impact of these programs has been a decreased transfer of patients abroad for treatment. Under the umbrella of the Emirates Thoracic Society (ETS) a platform for greater collaboration aimed at improving patient care, potential research and physician education has been created. Direct links have been established with world-leading Thoracic surgery and Respiratory Medicine Centers facilitating this development and offering support and guidance. This article charts these changes in thoracic care in the recent past, present, and delineates plans for the future in the UAE.

QT Prolongation in Critically Ill Patients With SARS-CoV-2 Infection.

BACKGROUND: Several reports linked the use of repurposed drugs such as hydroxychloroquine (HCQ), azithromycin, lopinavir/ritonavir, and favipiravir with QT interval prolongation in patients with SARS-CoV2 infection. Little is known about the risk factors for QT interval prolongation in this population. We sought to describe the prevalence and identify the main risk factors associated with clinically significant corrected QT (QTc) prolongation in this population. METHODS: We conducted a retrospective analysis of critically ill patients who were admitted to our intensive care unit (ICU), had at least one electrocardiogram performed during their ICU stay, and tested positive for SARs-CoV-2. Clinically significant QTc interval prolongation was defined as QTc >500 milliseconds (ms). RESULTS: Out of the 111 critically ill patients with SARS-CoV-2 infection, QTc was significantly prolonged in 47 cases (42.3%). Patients with a clinically significant QTc prolongation had significantly higher proportions of history of cardiac diseases/surgery (22 [46.8%] vs. 10 [15.6%], P < .001), hypokalemia (10 [21.3] vs. 5 [7.8%], P = .04), and male gender (95% vs. 82.8%, P = .036) than patients with QTc ≤500 ms, respectively. A total of 46 patients (41.4%) received HCQ, 28 (25.2%) received lopinavir/ritonavir, and 5 (4.5%) received azithromycin. Multivariate logistic regression analysis showed that a history of cardiac disease was the only independent factor associated with clinically significant QTc prolongation (P = .004 for the likelihood-ratio test). CONCLUSION: The prevalence of clinically significant QTc prolongation in critically ill patients with SARS-CoV-2 infection was high and independent of drugs used. Larger prospective observational studies are warranted to elucidate independent risk factors associated with clinically significant QTc prolongation in this study population.