Enabling Continuous Wearable Reflectance Pulse Oximetry at the Sternum.

In light of the recent Coronavirus disease (COVID-19) pandemic, peripheral oxygen saturation (SpO2) has shown to be amongst the vital signs most indicative of deterioration in persons with COVID-19. To allow for the continuous monitoring of SpO2, we attempted to demonstrate accurate SpO2 estimation using our custom chest-based wearable patch biosensor, capable of measuring electrocardiogram (ECG) and photoplethysmogram (PPG) signals with high fidelity. Through a breath-hold protocol, we collected physiological data with a wide dynamic range of SpO2 from 20 subjects. The ratio of ratios (R) used in pulse oximetry to estimate SpO2 was robustly extracted from the red and infrared PPG signals during the breath-hold segments using novel feature extraction and PPGgreen-based outlier rejection algorithms. Through subject independent training, we achieved a low root-mean-square error (RMSE) of 2.64 ± 1.14% and a Pearson correlation coefficient (PCC) of 0.89. With subject-specific calibration, we further reduced the RMSE to 2.27 ± 0.76% and increased the PCC to 0.91. In addition, we showed that calibration is more efficiently accomplished by standardizing and focusing on the duration of breath-hold rather than the resulting range in SpO2. The accurate SpO2 estimation provided by our custom biosensor and the algorithms provide research opportunities for a wide range of disease and wellness monitoring applications.

[Treatment of postoperative anterior mediastinitis, sternal osteomyelitis in a patient with a novel coronavirus infection]. / Lechenie posleoperatsionnogo perednego mediastinita, osteomielita grudiny u patsientki s novoi koronavirusnoi infektsiei (COVID-19).

The incidence of mediastinitis after median sternotomy makes up 1-3%. This complication results prolonged hospital-stay, significant increase in treatment cost and high mortality (up to 75%). Severe COVID-19 pneumonia is often manifested by coughing, that impairs sternum stability after osteosynthesis. Moreover, concomitant leukopenia increases the risk of mediastinitis. Viral pneumonia and mediastinitis are complicated by respiratory failure and mutually potentiate the negative effect. Negative pressure wound therapy (NPWT) with combined antibiotic therapy ensures a favorable outcome even in patients with postoperative mediastinitis and osteomyelitis combined with viral pneumonia.