Oximetry at admission as a predictor of tomographic and functional impairment after 3-6 months in hospitalized patients with COVID-19.

OBJECTIVE: To investigate characteristics that may be associated with radiologic and functional findings following discharge in patients with severe coronavirus disease 2019 (COVID-19). METHODS: This single-center, prospective, observational cohort study comprised patients aged >18 years who were hospitalized with COVID-19 pneumonia, between May and October 2020. After 3 to 6 months of discharge, patients were clinically evaluated and underwent spirometry, a 6-minute walk test (6MWT), and chest computed tomography (CT). Statistical analysis was performed using association and correlation tests. RESULTS: A total of 134 patients were included (25/114 [22%] were admitted with severe hypoxemia). On the follow-up chest CT, 29/92 (32%) had no abnormalities, regardless of the severity of the initial involvement, and the mean 6MWT distance was 447 m. Patients with desaturation on admission had an increased risk of remaining CT abnormalities: patients with SpO2 between 88 and 92% had a 4.0-fold risk, and those with SpO2 < 88% had a 6.2-fold risk. The group with SpO2 < 88% also walked shorter distances than patients with SpO2 between 88 and 92%. CONCLUSION: Initial hypoxemia was found to be a good predictor of persistent radiological abnormalities in follow-up and was associated with low performance in 6MWT.

68 Ga-nitroimidazole PET/CT imaging of hypoxia in tuberculosis: A case series.

Tuberculosis (TB) lesions in humans have been proven to be severely hypoxic with hypoxia leading to latency and dormancy of disease. Dormant TB lesions become less susceptible to standard TB treatment regimens with varying responses to treatment but may have increased susceptibility to nitroimidazole drugs. This in turn implies that positron emission tomography / computed tomography (PET/CT) imaging with radiolabelled nitroimidazoles may identify patients who will benefit from treatment with antimicrobial agents that are active against anaerobic bacteria. This case series aims to highlight the hypoxic uptake and retention of a novel 68 Ga-labelled hypoxia-seeking agent in TB lesions at different time points during anti-TB therapy using PET/CT imaging. Patients with confirmed TB underwent whole-body PET/CT after administration of a 68 Ga-nitroimidazole derivative at baseline and follow-up. Images were analysed both qualitatively and semi-quantitatively. Hypoxic uptake and change in uptake over time were analysed using lesion-to-muscle ratio (LMR) and lesion-to-blood ratio (LBR). 68 Ga-nitroimidazole avid lesions were demonstrated most frequently in the upper lobes of the lung. Low-grade hypoxic uptake was visualised in areas of consolidation, cavitation, nodules and lymph nodes. From baseline to follow-up imaging, the LMR increased with persistent hypoxic load despite morphologic improvement. This case series highlights the dynamic hypoxic microenvironment in TB lesions. From these initial data, it appears that 68 Ga-nitroimidazole is a promising candidate for monitoring hypoxic load in patients diagnosed with TB. Such imaging could identify patients who would benefit from individualised therapy targeting other mechanisms in the TB microenvironment with the intention to predict or improve treatment response.

Outcomes of hospitalized patients with COVID-19 pneumonia, hypoxia, and a normal initial chest roentgenogram.

BACKGROUND: Outcomes of patients with coronavirus disease (COVID-19) pneumonia, hypoxia, and an initial normal chest roentgenogram (CXR) are not well defined. This study aimed to analyze the factors associated with poor outcomes in these patients. METHODS: This retrospective study evaluated patients admitted with COVID-19 pneumonia, a CXR without infiltrates and hypoxemia requiring supplemental oxygen. Outcomes were compared based on D-dimer levels and included in-hospital mortality, need for mechanical ventilation, acute kidney injury, shock, and length of hospital stay. RESULTS: We identified 115 patients, 31 (27%) had D-dimer levels above 4 times upper limit of normal on admission. Predictors of mortality included elevated D-dimers in hypoxic patients, use of mechanical ventilation, acute kidney injury, shock, and elevated admission serum sodium and lactic dehydrogenase. CONCLUSIONS: Patients with COVID-19 and hypoxia on initial presentation despite a normal CXR had significant mortality rates, higher in those with elevated inflammatory markers. The use of inflammatory markers, such as D-dimer and serum ferritin levels, may assist in identifying patients with higher morbidity and mortality risks. Additional imaging with chest computed tomogram should be obtained if clinically indicated and avoidance of overreliance of a normal CXR in those patients.

Clinical and radiological findings of silent hypoxia among COVID-19 patients.

The aim of this study was to describe the clinical and radiological findings of COVID-19 patients with "silent hypoxia," who had no dyspnea on admission even though their oximetry saturation was less than 94%. This retrospective cohort study included all COVID-19 patients (n = 270) at a large tertiary care hospital between January 31 and August 31, 2020. Clinical and radiological characteristics of patients who met our criteria of "silent hypoxia", which included those who reported no dyspnea even though oximetry saturation was <94%, were extracted. Eight patients (3.0%) met the criteria for "silent hypoxia." The median age was 61 years (interquartile range [IQR]: 48.8-72.3), and five (62.5%) were men. All patients had consolidation on CT and showed a moderate to high COVID-19 CT severity score (median: 13.5, IQR: 10.8-15.3). The median FIO2 of the maximum oxygen required was 55 (IQR: 28-70)%. Two patients (25.0%) were intubated, and one patient (12.5%) underwent extracorporeal membrane oxygenation. Some COVID-19 patients with "silent hypoxia" may develop severe disease. Close and accurate monitoring of patients using arterial blood gas and pulse oximetry is necessary, regardless of their symptoms.

Quantitative assessment of lung involvement on chest CT at admission: Impact on hypoxia and outcome in COVID-19 patients.

BACKGROUND: The aim of this study was to quantify COVID-19 pneumonia features using CT performed at time of admission to emergency department in order to predict patients' hypoxia during the hospitalization and outcome. METHODS: Consecutive chest CT performed in the emergency department between March 1st and April 7th 2020 for COVID-19 pneumonia were analyzed. The three features of pneumonia (GGO, semi-consolidation and consolidation) and the percentage of well-aerated lung were quantified using a HU threshold based software. ROC curves identified the optimal cut-off values of CT parameters to predict hypoxia worsening and hospital discharge. Multiple Cox proportional hazards regression was used to analyze the capability of CT quantitative features, demographic and clinical variables to predict the time to hospital discharge. RESULTS: Seventy-seven patients (median age 56-years-old, 51 men) with COVID-19 pneumonia at CT were enrolled. The quantitative features of COVID-19 pneumonia were not associated to age, sex and time-from-symptoms onset, whereas higher number of comorbidities was correlated to lower well-aerated parenchyma ratio (rho = -0.234, p = 0.04) and increased semi-consolidation ratio (rho = -0.303, p = 0.008). Well-aerated lung (≤57%), semi-consolidation (≥17%) and consolidation (≥9%) predicted worst hypoxemia during hospitalization, with moderate areas under curves (AUC 0.76, 0.75, 0.77, respectively). Multiple Cox regression identified younger age (p < 0.01), female sex (p < 0.001), longer time-from-symptoms onset (p = 0.049), semi-consolidation ≤17% (p < 0.01) and consolidation ≤13% (p = 0.03) as independent predictors of shorter time to hospital discharge. CONCLUSION: Quantification of pneumonia features on admitting chest CT predicted hypoxia worsening during hospitalization and time to hospital discharge in COVID-19 patients.

Simulation-based uptraining improves provider comfort in the management of critically ill patients with COVID-19.

PURPOSE: The COVID-19 surge required the deployment of large numbers of non-intensive care providers to assist in the management of the critically ill. Institutions took a variety of approaches to "uptraining" such providers though studies describing methods and effectiveness are lacking. MATERIALS AND METHODS: One hundred and seventy-five providers underwent a 3 h simulation-based session focused on management of shock, mechanical ventilation, acute respiratory distress syndrome, and critical care ultrasound. All participants were sent surveys to assess their comfort with various aspects of critical care following return to their usual work environments. RESULTS: One hundred and eight providers of 175 (62%) completed the survey. Overall, 104/108 responders (96%) felt training either significantly or somewhat improved their knowledge in the management of ICU patients. Responders felt most comfortable in the management of hypoxemia in intubated patients and the management of ventilated patients with acute respiratory distress syndrome (93% strongly agree or agree, and 86% strongly agree or agree, respectively). Fewer responders felt more comfortable using focused echocardiography (70% strongly agree or agree) and lung ultrasonography in following progression of COVID-19 (76% strongly agree or agree). CONCLUSIONS: Simulation-based training improved provider comfort in the management of critically ill patients with COVID-19.

Radiographic and clinical neurologic manifestations of COVID-19 related hypoxemia.

The novel coronavirus SARS-CoV-2 is known to cause hypoxemia and acute respiratory distress syndrome (ARDS) in a significant portion of those with severe disease. Survivors of critical illness and ARDS often experience neurocognitive impairment but, to date, there is scant literature correlating radiographic hypoxic brain injury to hypoxemia related to ARDS. In this case series, we describe three cases of hypoxic brain injury seen on magnetic resonance imaging (MRI) in patients with hypoxemia secondary to COVID-19-related ARDS. The lack of severe observed hypoxemia in two of the cases suggests that unrecognized or asymptomatic hypoxemia may play a role in hypoxic brain injury related to COVID-19.

Early Neonatal SARS-CoV-2 Infection Manifesting With Hypoxemia Requiring Respiratory Support.

We describe a case of neonatal SARS-CoV-2 infection, in an infant diagnosed 3 days after birth, and manifesting with silent hypoxemia, requiring respiratory support.