Conventional oxygen therapy versus CPAP as a ceiling of care in ward-based patients with COVID-19: a multi-centre cohort evaluation.

BACKGROUND: Continuous positive airway pressure (CPAP) therapy is commonly used for respiratory failure due to severe COVID-19 pneumonitis, including in patients deemed not likely to benefit from invasive mechanical ventilation (nIMV). Little evidence exists demonstrating superiority over conventional oxygen therapy, whilst ward-level delivery of CPAP presents practical challenges. We sought to compare clinical outcomes of oxygen therapy versus CPAP therapy in patients with COVID-19 who were nIMV. METHODS: This retrospective multi-centre cohort evaluation included patients diagnosed with COVID-19 who were nIMV, had a treatment escalation plan of ward-level care and clinical frailty scale ≤ 6. Recruitment occurred during the first two waves of the UK COVID-19 pandemic in 2020; from 1st March to May 31st, and from 1st September to 31st December. Patients given CPAP were compared to patients receiving oxygen therapy that required FiO2 ≥0.4 for more than 12 hours at hospitals not providing ward-level CPAP. Logistic regression modelling was performed to compare 30-day mortality between treatment groups, accounting for important confounders and within-hospital clustering. FINDINGS: Seven hospitals provided data for 479 patients during the UK COVID-19 pandemic in 2020. Overall 30-day mortality was 75.6% in the oxygen group (186/246 patients) and 77.7% in the CPAP group (181/233 patients). A lack of evidence for a treatment effect persisted in the adjusted model (adjusted odds ratio 0.84 95% CI 0.57-1.23, p=0.37). 49.8% of patients receiving CPAP-therapy (118/237) chose to discontinue it. INTERPRETATION: No survival difference was found between using oxygen alone or CPAP to treat patients with severe COVID-19 who were nIMV. A high patient-initiated discontinuation rate for CPAP suggests a significant treatment burden. Further reflection is warranted on the current treatment guidance and widespread application of CPAP in this setting. FUNDING: L Pearmain is supported by the MRC (MR/R00191X/1). TW Felton is supported by the NIHR Manchester Biomedical Research Centre.

Phenylthiocarbamide (PTC) tasting, genetics, and depression.

Twenty-three (23) females who satisfied the Diagnostic Interview Schedule (DIS) DSM-III criteria for Major Depression were assessed with the Beck Depression Inventory (BDI), the Hamilton Rating Scale for Depression (HRS), the genetically based phenylthiocarbamide (PTC) taste test, and each subject provided a family history of depression. Results show that, compared with PTC nontasters, the tasters suffered deeper depressions, longer periods of sadness, symptoms that resembled "endogenous depression," and the tasters reported more family members afflicted with depression. The PTC taste test accounted for 20% of the variance on the BDI and on the HRS.

Phenylthiocarbamide (PTC) tasting and reported depression.

The phenylthiocarbamide (PTC) taste test was investigated for its potential as a genetically based biological marker for depression. One hundred and one male and female adults (including 6 patients hospitalized for depression), aged 18-36, completed a multifactor depression questionnaire that included the Beck Depression Inventory (BDI), a scale that measures severity of depression in mother and father, and a commercially prepared PTC (paper) taste test. As predicted, PTC tasters reported significantly higher levels of depression on the BDI than nontasters (p less than .05); also, they scored higher on 5 of the 21 items (p less than .05). Significantly more subjects who reported a mother debilitated by depression were PTC tasters (p less than .05). Limitations and implications of these findings are discussed.