Photoplethysmographic Scaling of Dyspnoea

Initiating invasive mechanical ventilation is a vital and delay-critical decision. Precise and timely prediction of impending respiratory failure would be highly consequential. Subjective evaluation of respiratory loading conditions is inconsistent, imprecise and may result in erroneous management. Photoplethysmographic (POP) waveform analysis provides a non-invasive, readily available tool to estimate breathing effort in a semiquantitative fashion. It is the aim of this study to examine: 1. if the degree of dyspnoea, when clinically assessed by means of the respiratory rate and SpO2 values, correlates with the SpO2 wave variations (ΔPOP) in ICU spontaneously breathing COVID-19 and non-COVID-19 patients. 2. if a ΔPOP threshold could be identified to adequately predict further need of orotracheal intubation and invasive mechanical ventilation. This study consists of three main steps: 1. Clinical evaluation of dyspnoea based on: 1.1. Respiratory rate 1.2. Oxygen saturation (SpO2) 2. Storage of SpO2 curve for ΔPOP computation according to a proprietary algorithm after offline POP analysis . 3. Within a time frame of 10 days from when the first two steps are met, monitor for need of invasive ventilatory support.