Assessment of the effectiveness of medical rehabilitation after COVID-19 based on the functional capacity of the cardiovascular and respiratory systems

Aim. To assess the effectiveness of medical rehabilitation after pneumonia associated with the novel coronavirus infection (COVID-19), based on the study of functional capacity of the cardiovascular system and the external respiratory system.Methods. The study included 70 patients who had COVID-19 pneumonia and underwent a medical rehabilitation program from September to December 2020. Before being included in the rehabilitation program, all patients underwent pulmonary function tests (PFT), including an assessment of the lungs diffusion capacity, cardiopulmonary exercise testing, multispiral computed tomography (MSCT) of the chest, echocardiography, an evaluation of the quality of life according to the SF-36 questionnaire and the severity of shortness of breath on the mMRC scale. The effectiveness of rehabilitation was evaluated against the changes in PFT parameters, exercise tolerance, and quality of life.Results. At the enrollment, 46% of patients retained lung tissue lesions shown by MSCT and accompanied by a decrease in the lung diffusion capacity (67 (55 - 79%) of predicted value), dyspnea of 1.6 (1.0 - 3.0) points according to mMRC scale, moderate level of exercise tolerance and quality of life. Complex cardiopulmonary rehabilitation for 12 - 14 days in a specialized hospital led to a significant improvement in the parameters of pulmonary gas exchange and ventilation, peak oxygen consumption, and an increase in the reserve capacity of the cardiorespiratory system. The factors limiting the improvement of pulmonary gas exchange were the older age of the patients and the increased pressure in the pulmonary artery system. The positive influence of rehabilitation on both the physical and psycho-emotional components of the quality of life was noted.Conclusion. Complex cardiopulmonary rehabilitation with the assessment of changes in the oxygen metabolism parameters and functional capacity of the cardiovascular and respiratory systems has shown to be safe and highly effective in the studied group of patients who have had COVID-19 pneumonia.

Non-invasive Measurement of Pulmonary Gas Exchange Efficiency: The Oxygen Deficit

The efficiency of pulmonary gas exchange has long been assessed using the alveolar-arterial difference in PO2, the A-aDO2, a construct developed by Richard Riley ~70years ago. However, this measurement is invasive (requiring an arterial blood sample), time consuming, expensive, uncomfortable for the patients, and as such not ideal for serial measurements. Recent advances in the technology now provide for portable and rapidly responding measurement of the PO2 and PCO2 in expired gas, which combined with the well-established measurement of arterial oxygen saturation via pulse oximetry (SpO2) make practical a non-invasive surrogate measurement of the A-aDO2, the oxygen deficit. The oxygen deficit is the difference between the end-tidal PO2 and the calculated arterial PO2 derived from the SpO2 and taking into account the PCO2, also measured from end-tidal gas. The oxygen deficit shares the underlying basis of the measurement of gas exchange efficiency that the A-aDO2 uses, and thus the two measurements are well-correlated (r2~0.72). Studies have shown that the new approach is sensitive and can detect the age-related decline in gas exchange efficiency associated with healthy aging. In patients with lung disease the oxygen deficit is greatly elevated compared to normal subjects. The portable and non-invasive nature of the approach suggests potential uses in first responders, in military applications, and in underserved areas. Further, the completely non-invasive and rapid nature of the measurement makes it ideally suited to serial measurements of acutely ill patients including those with COVID-19, allowing patients to be closely monitored if required.

TP10.1.12Personal Protective Equipment impairs pulmonary gas exchange causing systemic hypercapnia-hypoxaemia and cerebral hyperperfusion-induced cephalalgia

Aims To what extent Personal Protective Equipment (PPE) impacts integrated cardiopulmonary-cerebrovascular function has not been examined. The hypothesis tested was that PPE adversely influences pulmonary gas exchange, resulting in systemic hypercapnic-hypoxaemia and cerebral hyperperfusion-induced cephalalgia. Methods Eight male Higher Surgical Trainees (aged 33 ± 2y) participated in a repeated measures crossover study, completing two-hour laparoscopic simulation tasks, on two separate occasions (separate days), once in standard operating attire, and once in full PPE (including FFP3 mask). Results Following two hours of simulation, full PPE (compared with standard operating attire) was associated with increased FICO2 (7.9% (±0.8%) vs. 7.1% (±1.2%); p = 0.025), decreased FIO2 (16.0% (±0.4%) vs. 16.6% (±0.5%); p = 0.011), and decreased peripheral O2 saturation (95% (± 1%) vs. 98% (±1%); p = 0.001). Headaches were reported by three participants in PPE (Chi2 3.692, p = 0.055), and was associated with increased Middle Cerebral Artery flow velocity; 82 (±4) cm/s, compared with 63 (±9) cm/s in the remaining five participants (p = 0.008). Skin temperature increased by 1.3 °C during simulation in PPE (p = 0.001), with an equal mean insensible fluid loss of 300ml under both conditions (p = 0.049). Conclusions Collectively, these findings highlight the integrated cardiopulmonary-cerebrovascular complications associated with PPE-induced impairment in pulmonary gas exchange. Protective countermeasures should be designed to prevent risk to healthcare staff and patients alike.