Respiratory compensation point

2021 ◽  
pp. 93-96
Author(s):  
William J.M. Kinnear ◽  
James H. Hull
Keyword(s):  
Carbon Dioxide ◽  
Minute Ventilation ◽  
Cardiopulmonary Exercise Test ◽  
Compensation Point ◽  
Respiratory Compensation Point ◽  
Carbon Dioxide Output ◽  
Respiratory Compensation ◽  
Cardiopulmonary Exercise ◽  
The Subject ◽  
Maximal Effort

This chapter describes how acidaemia stimulates ventilation in the later stages of a cardiopulmonary exercise test (CPET). This happens after the anaerobic threshold, once the capacity of the blood to buffer lactic acid has been used up. The respiratory compensation point (RCP) can be identified from an increase in the slope when minute ventilation (VE) is plotted against carbon dioxide output (VCO2), or from a rise in the ventilatory equivalents for carbon dioxide (VeqCO2). The presence of a clear RCP indicates that the subject has made a fairly maximal effort during the CPET. An RCP also argues against significant lung disease, since it implies the ability to increase ventilation in response to acidaemia.

Carbon dioxide output

2021 ◽  
pp. 63-71
Author(s):  
William J.M. Kinnear ◽  
James H. Hull
Keyword(s):  
Carbon Dioxide ◽  
Lactic Acid ◽  
Oxygen Uptake ◽  
Dead Space ◽  
Exercise Test ◽  
Minute Ventilation ◽  
Cardiopulmonary Exercise Test ◽  
Carbon Dioxide Output ◽  
Cardiopulmonary Exercise ◽  
Ventilatory Equivalent

This chapter describes how carbon dioxide is produced from metabolism and also from buffering of lactic acid. The volume of carbon dioxide exhaled (VCO2) is calculated from the concentration in exhaled gas and minute ventilation. If the lungs are less efficient than normal, with a high dead space, the amount of ventilation needed to achieve any given VCO2 is much higher. This index, known as the ventilatory equivalent for carbon dioxide, is an important prognostic marker. Early on in a cardiopulmonary exercise test (CPET), VCO2 is slightly less than the oxygen uptake (VO2). As exercise reaches its maximum, VCO2 increases more quickly when acidaemia starts to stimulate ventilation.

scholarly journals An Automated Excess Minute Ventilation Method To Detect The Respiratory Compensation Point

2020 ◽  
Vol 52 (7S) ◽  
pp. 37-39
Author(s):  
Kyoung Jae Kim ◽  
Roxanne Buxton ◽  
James Crowell ◽  
Meghan Downs ◽  
Andrew Abercromby
Keyword(s):  
Minute Ventilation ◽  
Compensation Point ◽  
Respiratory Compensation Point ◽  
Respiratory Compensation ◽  
Ventilation Method

scholarly journals Cardiopulmonary Exercise Test, mMRC and GAP score Can Predict 1-year Mortality in Patients with Idiopathic Pulmonary Fibrosis: A Prospective Study

2021 ◽  
Author(s):  
Yuan-Yang Cheng ◽  
Shih-Yi Lin ◽  
Shin-Tsu Chang ◽  
Chu-Hsing Lin ◽  
Pin-Kuei Fu
Keyword(s):  
Carbon Dioxide ◽  
Idiopathic Pulmonary Fibrosis ◽  
Pulmonary Fibrosis ◽  
Exercise Test ◽  
Maximal Exercise ◽  
Heart Rate Recovery ◽  
Minute Ventilation ◽  
Cardiopulmonary Exercise Test ◽  
Cardiopulmonary Exercise ◽  
Asian Patients

Abstract Idiopathic pulmonary fibrosis (IPF) is a rare lung disease with high mortality. Finding an effective predictor of survival is therefore important for both clinicians and patients. In this prospective observational study, we evaluated the prognostic value of the parameters of cardiopulmonary exercise test (CPET), pulmonary function test (PFT), 6-min walk test (6MWT), and certain questionnaires on mortality in Asian patients with IPF. A total of 34 patients diagnosed with IPF were enrolled and followed up for 12 months, during which 6 patients died. The non-survivors had significantly higher minute ventilation to carbon dioxide output (VE/VCO2) slope, more oxygen desaturation during CPET and 6MWT, less heart rate recovery one minute after CPET, higher dead space, higher Gender-Age-Physiology (GAP) index and Modified Medical Research Council (mMRC) score. GAP index, mMRC score, VE/VCO2 slope, and end-tidal partial pressure of carbon dioxide (PETCO2) at maximal exercise demonstrated an area under curve (AUC) of >0.7, and the corresponding cutoff values were 4, 2, 35.1 and 3.6 kPa. Therefore, GAP index, mMRC scores, VE/VCO2 slope, and PETCO2 at maximal exercise could be important predictors for mortality in Asian patients with IPF.

scholarly journals Importance of Cardiopulmonary Exercise Testing Amongst Subjects Recovering from COVID-19

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 507
Author(s):  
Gianluigi Dorelli ◽  
Michele Braggio ◽  
Daniele Gabbiani ◽  
Fabiana Busti ◽  
Marco Caminati ◽  
...  
Keyword(s):  
Minute Ventilation ◽  
Objective Assessment ◽  
Cardiopulmonary Exercise Testing ◽  
Cardiopulmonary Exercise Test ◽  
Gas Analysis ◽  
Carbon Dioxide Output ◽  
Cardiopulmonary Exercise ◽  
The Relationship ◽  
Male Subjects ◽  
Ventilatory Limitation

The cardiopulmonary exercise test (CPET) provides an objective assessment of ventilatory limitation, related to the exercise minute ventilation (VE) coupled to carbon dioxide output (VCO2) (VE/VCO2); high values of VE/VCO2 slope define an exercise ventilatory inefficiency (EVin). In subjects recovered from hospitalised COVID-19, we explored the methodology of CPET in order to evaluate the presence of cardiopulmonary alterations. Our prospective study (RESPICOVID) has been proposed to evaluate pulmonary damage’s clinical impact in post-COVID subjects. In a subgroup of subjects (RESPICOVID2) without baseline confounders, we performed the CPET. According to the VE/VCO2 slope, subjects were divided into having EVin and exercise ventilatory efficiency (EVef). Data concerning general variables, hospitalisation, lung function, and gas-analysis were also collected. The RESPICOVID2 enrolled 28 subjects, of whom 8 (29%) had EVin. As compared to subjects with EVef, subjects with EVin showed a reduction in heart rate (HR) recovery. VE/VCO2 slope was inversely correlated with HR recovery; this correlation was confirmed in a subgroup of older, non-smoking male subjects, regardless of the presence of arterial hypertension. More than one-fourth of subjects recovered from hospitalised COVID-19 have EVin. The relationship between EVin and HR recovery may represent a novel hallmark of post-COVID cardiopulmonary alterations.

Respiratory exchange ratio

2021 ◽  
pp. 72-76
Author(s):  
William J.M. Kinnear ◽  
James H. Hull
Keyword(s):  
Carbon Dioxide ◽  
Lactic Acid ◽  
Oxygen Uptake ◽  
Respiratory Exchange Ratio ◽  
Cardiopulmonary Exercise Test ◽  
Peak Exercise ◽  
Carbon Dioxide Output ◽  
Cardiopulmonary Exercise ◽  
Physiological Processes ◽  
Dysfunctional Breathing

This chapter describes how the respiratory exchange ratio (RER) is calculated by dividing carbon dioxide output (VCO2) by the oxygen uptake (VO2). At the start of a cardiopulmonary exercise test (CPET), this ratio is less than 1.0. Once anaerobic metabolism starts to kick in, more carbon dioxide is produced from buffering of lactic acid and the RER starts to climb. At peak exercise, RER values of 1.4 or higher indicate that the subject’s effort is pretty maximal. An erratic RER trace is seen in dysfunctional breathing, when psychological, rather than physiological, processes are involved in controlling breathing.

scholarly journals EMG breakpoints for detecting anaerobic threshold and respiratory compensation point in recovered COVID-19 patients

2021 ◽  
pp. 102567
Author(s):  
Murillo Frazão ◽  
Paulo Eugênio Silva ◽  
Lucas de Assis Pereira Cacau ◽  
Tullio Rocha Petrucci ◽  
Mariela Cometki Assis ◽  
...  
Keyword(s):  
Anaerobic Threshold ◽  
Compensation Point ◽  
Respiratory Compensation Point ◽  
Respiratory Compensation
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