Cardiopulmonary exercise testing (CPET) was limited to peak oxygen consumption analysis (VO₂peak), and now the ventilation/carbon dioxide production (VE/VCO₂) slope is recognized as having independent prognostic value. Unlike VO₂peak, the VE/VCO₂ slope does not require maximal effort, making it more feasible. There is no consensus on how to measure the VE/VCO₂ slope; therefore, we assessed whether different methods affect its value. This is a retrospective study assessing sociodemographic data, left ventricular ejection fraction, CPET parameters, and indications of patients referred for CPET. The VE/VCO₂ slope was measured to the first ventilatory threshold (VT1-slope), secondary threshold (VT2-slope), and included all test data (full-slope). Of the 697 CPETs analyzed, 308 reached VT2. All VE/VCO₂ slopes increased with age, regardless of test indications. In patients not reaching VT2, the VT1-slope was 32 vs. 36 (p < 0.001) for the full-slope; in those surpassing VT2, the VT1-slope was 29 vs. 33 (p < 0.001) for the VT2-slope and 37 (all p < 0.001) for the full-slope. The mean difference between the submaximal and full-slopes was ±4 units, sufficient to reclassify patients from low to high risk for heart failure or pulmonary hypertension. We conclude that the method used for determining the VE/VCO₂ slope greatly influences the result, the significant variations limiting its prognostic value. The calculation method must be standardized to improve its prognostic value.

The current gold-standard treatment for COVID-19-related hypoxemic respiratory failure is invasive mechanical ventilation. However, do not intubate orders (DNI), prevent the use of this treatment in some cases. The aim of this study was to evaluate if non-invasive ventilatory supports can provide a good therapeutic alternative to invasive ventilation in patients with severe COVID-19 infection and a DNI. Data were collected from four centres in three European countries. Patients with severe COVID-19 infection were included. We emulated a hypothetical target trial in which outcomes were compared in patients with a DNI order treated exclusively by non-invasive respiratory support with patients who could be intubated if necessary. We set up a propensity score and an inverse probability of treatment weighting to remove confounding by indication. Four-hundred patients were included: 270 were eligible for intubation and 130 had a DNI order. The adjusted risk ratio for death among patients eligible for intubation was 0.81 (95% CI 0.46 to 1.42). The median length of stay in acute care for survivors was similar between groups (18 (10–31) vs. (19 (13–23.5); p = 0.76). The use of non-invasive respiratory support is a good compromise for patients with severe COVID-19 and a do not intubate order.

Purpose: The purpose of this study was to determine and compare the effectiveness of three different resistance training (RT) methods for cardiac rehabilitation. Methods: Individuals with heart failure with reduced ejection fraction (HFrEF, n = 23) or coronary artery disease (CAD, n = 22) and healthy controls (CTRL, n = 29) participated in this randomized crossover trial of RT exercises at 70% of the one-maximal repetition on a leg extension machine. Peak heart rate (HR) and blood pressure (BP) were measured noninvasively. The three RT methods were five sets of increasing repetitions from three to seven (RISE), of decreasing repetitions from seven to three (DROP), and three sets of nine repetitions (USUAL). Interset rest intervals were 15 sec for RISE and DROP and 60 sec for USUAL. Results: Peak HR differed on average by <4 bpm between methods in the HFrEF and CAD groups (P < .02). Rises in systolic BP (SBP) in the HFrEF group were comparable across methods. In the CAD group, mean SBP at peak exercise increased more in RISE and DROP than in USUAL (P < .001), but the increase was ≤10 mm Hg. In the CTRL group, SBP was higher for DROP than for USUAL (152 ± 22 vs 144 ± 24 mm Hg, respectively; P < .01). Peak cardiac output and perceived exertion did not differ between methods. Conclusions: The RISE, DROP, and USUAL RT methods induced a similar perception of effort and similar increases in peak HR and BP. The RISE and DROP methods appear more efficient as they allow a comparable training volume in a shorter time than the USUAL method.

Our aim was to evaluate the benefits of cardio-pulmonary rehabilitation on severe to moderate COVID-19 patients. 25 discharged COVID-19 patients underwent a cardio-pulmonary test (CPET), a spirometry test and a measure of carbon monoxide lung diffusion capacity (DLCO) at the beginning of their rehabilitation program and after 23 ± 5 rehabilitation sessions. This rehabilitation program combined interval training exercises on a bike and resistance exercises for major muscle groups. We then compared their progress in rehabilitation to that obtained with cardiac patients. At the beginning of their rehabilitation program, COVID-19 patients presented a reduced physical capacity with a maximal aerobic capacity (VO₂ max) at 71% of predicted value, a maximal workload at 70% of predicted value and an exercise hyperventilation measured by a higher VE/VCO₂ slope. Exercise was mainly limited by muscle deconditioning. After rehabilitation, the VO₂ max and maximal workload increased in COVID 19 patients by 18% and 26%, respectively. In patients with ischemic heart disease the post-rehabilitation gains in VO2 max and maximal workload were 22% and 25%, respectively. Moreover, exercise hyperventilation decreased by 10% in both groups. On the other hand, the intrinsic pulmonary function of COVID 19 patients improved following natural recovery. In conclusion, even if cardio-pulmonary rehabilitation is probably not the only parameter which explains the partial recovery of moderate to severe COVID-19 patients, it certainly helps to improve their physical capacity and reduce exercise hyperventilation.

The different waves of the COVID-19 pandemic caused dramatic issues regarding the organization of care. In this context innovative solutions have to be developed in a timely manner to adapt to the organization of the care. The establishment of middle care (MC) units is a bright example of such an adaptation. A multidisciplinary MC team, including expert and non-expert respiratory health care personnel, was developed and trained to work in a COVID-19 MC unit. Important educational resources were set up to ensure rapid and effective training of the MC team, limiting the admission or delaying transfers to ICU and ensuring optimal management of palliative care. We conducted a retrospective analysis of patient data in the MC unit during the second COVID-19 wave in Belgium. The aim of this study was to demonstrate the feasibility of quickly developing an effective respiratory MC unit mixing respiratory expert and non-expert members from outside ICUs. The establishment of an MC unit during a pandemic is feasible and needed. MC units possibly relieve the pressure exerted on ICUs. A highly trained multidisciplinary team is key to ensuring the success of an MC unit during such kind of a pandemic.