Extracorporeal membrane oxygenation for COVID-19: An evolving experience through multiple waves.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) has shown variable results in COVID-19 pneumonia however, some evidence supports benefit. Here we compare our institution's ECMO outcomes across multiple waves of the COVID-19 pandemic. METHODS: All patients who received ECMO for COVID-19 between March 1, 2020, and March 1, 2021, were reviewed. Patients received venovenous (VV) or right ventricular assist device (RVAD/ECMO) ECMO. Early (March 1-July 6, 2020, Era 1) and late (July 7, 2020-March 1, 2021, Era 2) pandemic RVAD/ECMO patients were compared. RESULTS: Fifty-four patients received ECMO of which 16 (29.6%) patients received VV ECMO and 38 (70.4%) RVAD/ECMO. Median age was 53.0 years, body mass index 36.1 kg/m2 , 41.2% female, and 49% Caucasian. The most common pre-cannulation treatments included steroids (79.6%) and convalescent plasma (70.4%). Median time from admission to cannulation was 7.0 days. Median support time was 30.5 days (VV ECMO 35.0 days, RVAD/ECMO 26.0 days). In- hospital mortality was 42.6% (39.5% RVAD/ECMO, 50.0% VV ECMO). Significant morbidities included infection (80.8%), bleeding events (74.5%), and renal replacement therapy (30.8%). Cumulative mortality 120-days post-cannulation was 45.7% (VV ECMO 60.8%, RVAD/ECMO 40.0%). RVAD/ECMO Era 1 demonstrated a significantly lower cumulative mortality (16.2%) compared to Era 2 (60.4%). Competing risk analysis found age (HR 0.95, [95% CI 0.92, 0.98] p = 0.005) to be a protective factor for survival. CONCLUSION: ECMO support for COVID-19 is beneficial but carries significant morbidity. RVAD/ECMO support demonstrated consistent advantages in survival to VV-ECMO, but with declining efficacy across time during the COVID-19 pandemic.

Arterial flow waveforms, vascular tone, and chronic fatigue: a case report.

We present the case of a patient with chronic fatigue secondary to Postural Orthostatic Tachycardia Syndrome (POTS) who had distinctive abnormalities in his arterial waveform morphology as assessed by pulse oximetry. Moreover, the patient's arterial waveform changed markedly from being supine to upright, suggesting that arterial flow patterns may be abnormal in our patient. Analysis of the waveform suggested a positional hypovolemia as the cause of his orthostatic intolerance. We review general aspects of arterial flow waveform analysis pertinent to health care providers and discuss the pathophysiology of POTS.

Comparison of physical examination and fluorodeoxyglucose positron emission tomography/computed tomography 4-6 months after radiotherapy to assess residual head-and-neck cancer.

PURPOSE: To retrospectively compare fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) and physical examination 4-6 months after radiotherapy for assessing residual head-and-neck cancer (HNC). METHODS AND MATERIALS: From July 2002 through March 2006, 52 HNC patients underwent definitive radiotherapy or chemoradiotherapy. Categoric assessments of residual tumor by PET/CT and physical examination 4-6 months after therapy were correlated and compared with clinical outcomes. Pretreatment data, including tumor stage and primary site standardized uptake value, were also gathered retrospectively and correlated with clinical outcomes. Median follow-up time was 58 months. RESULTS: Twenty-one patients had either locoregionally "positive" (17 of 21) or "equivocal" (4 of 21) PET/CT scans, whereas 31 patients had locoregionally negative scans. Four patients failed treatment and had biopsy-confirmed residual or recurrent local disease. All patients, including patients with locally suspicious scans or examinations who refused biopsies, were followed clinically for a minimum of 29 months after therapy, with no other cases of treatment failure detected during this time. No patient had residual nodal disease after therapy. Sensitivities of PET/CT vs. physical examination for early detection of treatment failure were 100% vs. 50%, whereas the specificities of the two modalities were 64.6% vs. 89.6%, respectively. Higher initial T stage and American Joint Commission on Cancer stage correlated with increased incidence of positive/equivocal PET/CT results and treatment failure. Maximal standardized uptake value was not predictive of any clinical outcome. CONCLUSIONS: A negative result on PET/CT obtained 4-6 months after radiotherapy is highly sensitive and correlates with successful locoregional control. Patients with negative scans may reasonably be spared invasive diagnostic procedures, such as biopsy and neck dissection, unless recurrent disease is suspected on clinical grounds. Close follow-up is prudent for HNC patients with abnormal findings on posttherapy PET/CT scan.

Sequence preference in RNA recognition by the nucleoporin Nup153.

The vertebrate nuclear pore protein Nup153 contains a novel RNA binding domain. This 150-amino acid region was previously found to bind preferentially to a panel of mRNAs when compared with structured RNAs, such as tRNA, U snRNA, and double-stranded RNA. The ability to broadly recognize mRNA led to the conclusion that the Nup153 RNA binding domain confers a general affinity for single-stranded RNA. Here, we have probed Nup153 RNA recognition to decipher how this unique RNA binding domain discriminates between potential targets. We first mapped the binding determinant within an RNA fragment that associates relatively robustly with the Nup153 RNA binding domain. We next designed synthetic RNA oligonucleotides to systematically delineate the features within this minimal RNA fragment that are key to Nup153 RNA-binding domain binding and demonstrated that the binding preferences of Nup153 do not reflect general preferences of an mRNA/single-stranded RNA-binding protein. We further found that the association between Nup153 and a cellular mRNA can be attributed to an interaction with specific subregions of the RNA. These results indicate that Nup153 can discriminate between mRNA and other classes of RNA transcripts due in part to direct recognition of a loose sequence motif. This information adds a new dimension to the interfaces that can contribute to recognition in mRNA export cargo selection and fate.