Prone positioning of patients with moderate hypoxaemia due to covid-19: multicentre pragmatic randomised trial (COVID-PRONE).

OBJECTIVES: To assess the effectiveness of prone positioning to reduce the risk of death or respiratory failure in non-critically ill patients admitted to hospital with covid-19. DESIGN: Multicentre pragmatic randomised clinical trial. SETTING: 15 hospitals in Canada and the United States from May 2020 until May 2021. PARTICIPANTS: Eligible patients had a laboratory confirmed or a clinically highly suspected diagnosis of covid-19, needed supplemental oxygen (up to 50% fraction of inspired oxygen), and were able to independently lie prone with verbal instruction. Of the 570 patients who were assessed for eligibility, 257 were randomised and 248 were included in the analysis. INTERVENTION: Patients were randomised 1:1 to prone positioning (that is, instructing a patient to lie on their stomach while they are in bed) or standard of care (that is, no instruction to adopt prone position). MAIN OUTCOME MEASURES: The primary outcome was a composite of in-hospital death, mechanical ventilation, or worsening respiratory failure defined as needing at least 60% fraction of inspired oxygen for at least 24 hours. Secondary outcomes included the change in the ratio of oxygen saturation to fraction of inspired oxygen. RESULTS: The trial was stopped early on the basis of futility for the pre-specified primary outcome. The median time from hospital admission until randomisation was 1 day, the median age of patients was 56 (interquartile range 45-65) years, 89 (36%) patients were female, and 222 (90%) were receiving oxygen via nasal prongs at the time of randomisation. The median time spent prone in the first 72 hours was 6 (1.5-12.8) hours in total for the prone arm compared with 0 (0-2) hours in the control arm. The risk of the primary outcome was similar between the prone group (18 (14%) events) and the standard care group (17 (14%) events) (odds ratio 0.92, 95% confidence interval 0.44 to 1.92). The change in the ratio of oxygen saturation to fraction of inspired oxygen after 72 hours was similar for patients randomised to prone positioning and standard of care. CONCLUSION: Among non-critically ill patients with hypoxaemia who were admitted to hospital with covid-19, a multifaceted intervention to increase prone positioning did not improve outcomes. However, wide confidence intervals preclude definitively ruling out benefit or harm. Adherence to prone positioning was poor, despite multiple efforts to increase it. Subsequent trials of prone positioning should aim to develop strategies to improve adherence to awake prone positioning. STUDY REGISTRATION: ClinicalTrials.gov NCT04383613.

Duplex Doppler Ultrasound of the Hepatic Artery: A Window to Diagnosis of Diffuse Liver Pathology.

The use of Doppler sonography for evaluation of the liver is well established, and evaluation of the portal and hepatic veins in native livers, as well as the hepatic artery in transplant livers, is a standard part of the examination. Less well known, however, is that assessment hepatic of artery blood flow velocities and waveforms can permit inferences to be made about liver and system pathophysiology even in native livers. This review will illustrate that hepatic parenchymal abnormalities, as well as primary vascular abnormalities both upstream and downstream of the proper hepatic artery, can be inferred from careful interrogation of its Doppler signature during routine abdominal sonography.

Pro/con debate: should PaCO2 be tightly controlled in all patients with acute brain injuries?

You are the attending intensivist in a neurointensive care unit caring for a woman five days post-rupture of a cerebral aneurysm (World Federation of Neurological Surgeons Grade 4 and Fisher Grade 3). She is intubated for airway protection and mild hypoxemia related to an aspiration event at the time of aneurysm rupture, but is breathing spontaneously on the ventilator. Your patient is spontaneously hyperventilating with high tidal volumes despite minimal support and has developed significant hypocapnia. She has not yet developed the acute respiratory distress syndrome. You debate whether to tightly control her partial pressure of arterial carbon dioxide, weighing the known risks of acute hypocapnia in other forms of brain injury against the potential loss of clinical neuromonitoring associated with deep sedation and neuromuscular blockade in this patient who is at high risk of delayed ischemia from vasospasm. You are also aware of the potential implications of tidal volume control if this patient were to develop the acute respiratory distress syndrome and the effect of permissive hypercapnia on her intracranial pressure. In this paper we provide a detailed and balanced examination of the issues pertaining to this clinical scenario, including suggestions for clinical management of ventilation, sedation and neuromonitoring. Until more definitive clinical trial evidence is available to guide practice, clinicians are forced to carefully weigh the potential benefits of tight carbon dioxide control against the potential risks in each individual patient based on the clinical issues at hand.

Polyoma virus nephropathy-related mass lesion in an apparently immunocompetent patient.

Polyoma virus is a recognized cause of hemorrhagic cystitis, viral nephropathy, and ureteral stricture in renal and stem cell transplant recipients. Rarely, polyoma virus causes native kidney and bladder pathology in heavily immunosuppressed patients. We report a unique case of native kidney polyoma virus nephropathy, urothelial ulceration, and renal pelvic fibrosis presenting as a mass lesion in a non-debilitated, apparently immunocompetent man. Based on radiologic, ureterorenoscopic, and urine cytologic findings, a laparoscopic nephrectomy was performed. However, nephrectomy revealed a hemorrhagic scar-like lesion, with urothelial ulceration, but no neoplasm or malignancy. Histopathologic evaluation and immunostaining revealed polyoma viral infection in the nearby renal medulla. This case adds polyoma virus nephropathy to the differential diagnosis of non-neoplastic and reactive masses, which may mimic renal malignancy.

The attitude of Canadian university students toward a behavior-based blood donor health assessment questionnaire.

BACKGROUND: In Canada, all men who have sex with men (MSM) are indefinitely deferred from donating blood. The purpose of this study was to determine the acceptability of an alternative behavior-based donor health questionnaire among Canadian university students. Further we sought to determine the perception of blood safety associated with specific risk behaviors. STUDY DESIGN AND METHODS: Questions found on the Canadian Blood Services' donor health assessment questionnaire as well as from studies assessing high-risk behavior for human immunodeficiency virus infection were included. For each question participants were asked to rate the acceptability, comfort in answering, perceived effect on blood safety, and whether the question would deter them from donating blood. Data were analyzed using nonparametric tests. RESULTS: A total of 741 students participated in the study. Questions regarding sexual practices of the donor were rated less important for blood safety compared to those assessing for sexually transmitted infections, sex for money, and injection drug use (30%-62% vs. 69%-95% unsafe). A total of 24.4% of students rated both questions on MSM status and a behavior-based alternative as equally unacceptable. We found an inverse correlation between perception of safety and acceptability of questions. CONCLUSION: Our findings suggest that a behavior-based screening modification is unlikely to change opinions or satisfy those who object to the MSM current policy in place. Acceptability of these questions might be related to a poor understanding of the effect of sexual practices on blood supply safety.