Academic literature on the topic 'Cardio-pulmonary exercise testing'

This article reviews the benefits of pre-assessment with cardio-pulmonary exercise testing (CPX) and the effectiveness of preoperative interventions in high-risk patients undergoing major surgery. Three patient case studies will be presented from local practice, to give examples of how patients' co-morbidity has been improved prior to surgery or how decisions for surgery can be modified as a result of the CPX test.

Objectives: To investigate whether recreational alpine skiing in the elderly can improve cardio-pulmonary fitness. Design: Randomized controlled study with pre–post repeated measurements. Methods: A total of 48 elderly participants (60–76 years) were randomly assigned to either participate in a 12-week guided recreational skiing program (intervention group, IG, average of 28.5 ± 2.6 skiing days) or to continue a sedentary ski-free lifestyle (control group, CG). Cardio-pulmonary exercise testing (CPET) and pulmonary function testing were performed in both groups before (PRE) and after (POST) the intervention/control period to compare parameters PRE vs. POST CPET. Results: At baseline, IG and CG did not differ significantly with respect to CPET and pulmonary function parameters. At POST, several measures of maximal exercise capacity and breathing economy were significantly improved in IG as compared to CG: maximal oxygen capacity (IG: 33.8 ± 7.9; CG: 28.7 ± 5.9 mL/min/kg; p = 0.030), maximal carbon dioxide production (IG: 36.2 ± 7.7; CG: 31.8 ± 6.5 mL/min/kg; p = 0.05), maximal oxygen pulse (IG: 16.8 ± 4.2; CG: 13.2 ± 4 mL/heart beat; p = 0.010), maximal minute ventilation (IG: 96.8 ± 17.8; CG: 81.3 ± 21.9 l/min; p = 0.025), and maximal metabolic equivalent of task (METs, IG: 9.65 ± 2.26; CG: 8.19 ± 1.68 METs; p = 0.029). Except for oxygen pulse, these significant changes could also be observed at the anaerobic threshold. Maximal heart rate and pulmonary function parameters remained essentially unchanged. Conclusion: Regular recreational skiing improves cardio-pulmonary fitness along with breathing economy and thus can contribute to a heart-healthy lifestyle for the elderly.

<strong>Background:</strong> Autonomic dysfunction (AD) and cardio-pulmonary exercise testing (CPET) parameters have been associated with masked heart failure with preserved ejection fraction (HFpEF) in the general population. Their clinical significance for masked HFpEF in chronic obstructive pulmonary disease (COPD) is however elusive. <strong>Aim:</strong> The aim of the study was to determine the prevalence, correlation and clinical significance of AD and CPET with masked HFpEF, in non-severe COPD patients, complaining of exertional dyspnea, without clinically overt cardio-vascular (CV) comorbidities (ischaemic heart disease, heart failure, uncontrolled arterial hypertension). <strong>Methods and results:</strong> We applied CPET and echocardiography in 68 COPD subjects. Echocardiography was performed before CPET and 1-2 minutes after peak exercise. Patients were divided into two groups: patients with and without masked HFpEF. Peak E/e' – 15 was applied as a cut-off. Chronotropic incompetence (CI) was assumed if both failure to reach the target heart rate (HR) on exercise and diminished heart rate reserve &lt; 80% occurred. Abnormal HR recovery (HRR) was taken if the decline is less than 12 beats within the first minute after exercise cessation. Univariate regression showed association between masked HFpEF, HRR, 'VO2, 'VO2 at AT, oxygen pulse and 'VE/'VCO2 slope. The multivariate regression demonstrated HRR as the only independent predictor of masked HFpEF – OR 10.28; 95% CI (3.55-29.80). <strong>Conclusion:</strong> Abnormal HRR is the only independent predictor of masked HFpEF in non-severe COPD patients. Despite of being associated with masked HFpEF, the lower 'VO2, lower oxygen pulse, higher 'VE/'VCO2 slope and lower exercise load seem to be the consequences, rather than the triggers for it.

<strong>Background:</strong>&nbsp;Cardiovascular risk factors are increasingly prevalent in young Indian adults, contributing to the burden of cardiovascular diseases (CVDs). Cardiopulmonary exercise testing (CPET) holds potential as a tool for risk stratification in this population.&nbsp;<strong>Aim and Objective:</strong>&nbsp;To assess the associations between exercise parameters and demographic/physiological factors in young Indian patients with cardiac risk factors.&nbsp;<strong>Materials and Methods:</strong>&nbsp;A prospective cross-sectional study was conducted on 30 young Indian patients (18-40 years) with cardiac risk factors. Demographic data, clinical characteristics, and exercise parameters (VO₂max, BR, AT, OUES) were assessed. Pearson correlation coefficients were calculated to investigate associations between exercise parameters and demographic/physiological factors, including age, height, weight, BMI, and systolic blood pressure.&nbsp;<strong>Results:</strong>&nbsp;Among the participants, 66.67% were males, and 33.33% were females. VO₂max negatively correlated with advancing age (r = -0.624, p &lt; 0.001). BR showed a positive correlation with height (r = 0.434, p &lt; 0.05). AT exhibited negative correlations with weight (r = -0.450, p &lt; 0.05) and BMI (r = -0.493, p &lt; 0.05). OUES positively correlated with height (r = 0.464, p &lt; 0.05). VO₂max positively correlated with systolic blood pressure (r = -0.380, p &lt; 0.05).&nbsp;<strong>Conclusion:</strong>&nbsp;In young Indian patients with cardiac risk factors, advancing age negatively impacted VO₂max, while height positively influenced BR and OUES. Weight, BMI, and systolic blood pressure were associated with AT and VO₂max. These findings shed light on the intricate interplay between exercise parameters and demographic/physiological factors, offering insights for risk stratification and tailored interventions in this high-risk population. &nbsp; &nbsp;

Currently, the American College of Sports Medicine (ACSM) recommends that protocols for cardiopulmonary exercise testing (CPET) should last between eight and twelve minutes. However, the justification for these exercise durations rely on limited experimental data. These recommendations have a significant impact on the ability of frail patients to be assessed using CPET and should conform to evidence based practice. This thesis begins by assessing the validity of these recommendations in relation to maximal exercise responses before assessing the consequences of these recommendations on sub-maximal exercise measurements. These studies were conducted in a relatively large cohort (compared to the study that underpins the ACSM guidelines) of heterogeneous volunteers (they are both men and women, with a significant age range and varied functional capacity) to make the data more relevant to clinical exercise testing. The data presented in chapter three demonstrate that it is very difficult to obtain exercise duration conforming to the current ACSM guidelines by using a standardised ramp exercise protocol on both treadmill and cycle ergometer exercise. However, sub-group analyses for those subjects who achieved moderate (8-12 minutes) and short (less than 8 minutes) exercise durations. In addition, a separate analysis was carried out for a different sub-group of those who achieved moderate (8-12 minutes) and long (more than 12 minutes) of durations of exercise. Despite this, it was possible to demonstrate in sub-group analysis that there was no significant difference in peak oxygen uptake, peak carbon dioxide output, peak heart rate, peak ventilation and peak power output when exercise duration was less or more than that prescribed by the ACSM recommendations. In addition, the effects of long, moderate or short duration exercise per se were also analysed in this chapter and again exercise duration was shown to be without effect on the main maximal markers of exercise performance. In chapters four, five and six, the initial findings were extended to determine the effects of exercise duration on a range of clinically relevant sub-maximal markers of exercise performance. It was likely, since exercise duration did not affect maximal exercise that the physiological determinants of maximal performance were not significantly altered during short or long duration exercise and consequently it was likely that sub-maximal markers of functional capacity would not be affected. However, the quality of the data obtained during CPET can obviously influence the accurate measurement physiological responses during exercise and much of the analysis in these chapters focused on the validity of the data analysis. Chapter four investigated the limitations to measuring the break point in the relationship between oxygen uptake and carbon dioxide output during progressive exercise (the so called ventilatory threshold or ‘V-slope’). The accurate measurement of this break point was determined by standard gas exchange criteria and the effects of reducing the data available for analysis (by reducing the amount of breaths available for comparison at reduced exercise durations) were examined. The data showed that reducing the data available for analysis had an impact on the quality of the data (decreasing the goodness of fit) but no significant effect on the determination of the ventilatory threshold. Chapter five determined the effects of exercise duration on the oxygen uptake efficiency slope (OUES). As expected, the effects of exercise duration were not significant but additional investigation into the commonly employed data analysis procedures was performed. These data show that the log transformation of the relationship between ventilation and oxygen uptake allows reliable assessment of ventilatory efficiency in most cases, however, the impact of the lactate threshold on ventilation and the biological variability in where the threshold occurs as a proportion of functional capacity can impact on the sensitivity of this measurement to predict aerobic and/or anaerobic capacity. Chapter six determined the effects of exercise duration on the breathing reserve index and found no significant difference during short, moderate or long exercise duration exercise. Further analysis was performed to demonstrate limitations in the use of predicted maximum voluntary ventilation (rather than direct measurement). Taken together, these data demonstrate that the current ACSM recommendations for CPET are too restrictive and may limit the application of such testing in populations that cannot exercise for between eight and twelve minutes. The data further suggest that the testing and analysis procedures used during CPET are central to producing valid maximal and sub-maximal markers of functional capacity and the recommendations should focus include guidelines in relation to such aspects.

Chronic obstructive pulmonary disease (COPD) is a progressive and disabling condition characterised with an obstruction to expiration that is not wholly reversible. Exercise training is an important component in the management of people with COPD, and improves exercise capacity, health-related quality of life. Bilevel non-invasive ventilation (NIV) during exercise in people with severe COPD is an adjunct that has been shown to increase exercise endurance which may be beneficial in aiding the achievement of an adequate volume of exercise to elicit a physiological training response, which, in turn, can reduce exercise-related breathlessness and allow greater levels of exercise performance. To investigate the effect of bilevel NIV on ventilatory and metabolic variables, and exercise outcomes, measurements with cardiopulmonary exercise test (CPET) systems are required. Exercise testing with CPET systems at atmospheric pressure is common however such measurements could be impacted by the positive pressure when used with bilevel NIV. Determining the accuracy of a commercially available CPET system is important to be able to reliably conduct a trial investigating changes in exercise outcomes with and without bilevel NIV. In people with COPD, airway resistance is increased, and expiratory time during exercise can be insufficient to exhale all the air before chemoreceptor stimulus triggers inspiration. Incomplete lung emptying during exercise increases end-expiratory lung volume above the equilibrium point of the respiratory system and is called dynamic hyperinflation (DH). Once DH raises peak inspiratory volumes to a critical threshold near total lung capacity, the cost of breathing at this high lung volume increases dyspnoea exponentially and limits exercise performance. Bilevel NIV could reduce DH during exercise by changing the pattern of breathing, favouring larger tidal volumes (VT), lower respiratory rates (RR) and a prolongation of expiratory time. The reductions in muscular effort when using bilevel NIV during exercise can also reduce the work of breathing and ventilatory stimulus further reducing DH for the same amount of exercise. Finally, bilevel NIV has an expiratory positive airway pressure (EPAP) which can further offset work of breathing and increase inspiratory capacity at rest. The level of EPAP provided may need to be individualised to account for variations in lung mechanics. Previous studies have reported an increase in time required to aid patients using NIV during exercise and suggest it may not be feasible outside centres without experienced staff to manage both the ventilator and patients using bilevel NIV. Further, even with improvements in exercise capacity, current guidelines recommend that NIV is used in selected individuals who are unable to derive satisfactory gains from standard exercise training. Perceptions of people using bilevel NIV during exercise for the first time are important to inform future research and development of bilevel NIV during exercise. The effect of bilevel NIV on DH and whether a reduction in DH is linked to improved exercise capacity has yet to be investigated. Whether any improvement in exercise capacity or change in DH with bilevel NIV is correlated with resting hyperinflation is also still unclear. In addition, whether an individually titrated EPAP is superior to a standard level of EPAP in reducing DH during exercise and improving exercise endurance time has also not been investigated. Finally, research and evidence on people with COPDs perceptions of using bilevel NIV during exercise is needed. The aims of the work presented in this thesis were to: 1. Examine the effect of measurements with bilevel NIV compared to without bilevel NIV on the measurement accuracy of tidal volume, respiratory rate, oxygen uptake and carbon dioxide production using mechanical simulation of ventilatory and metabolic variables. 2. Determine the effect of bilevel NIV during exercise on DH at isotime exercise and exercise endurance time compared to without NIV. Secondary aims were to determine whether bilevel NIV with an individually titrated EPAP (T-EPAP) was superior to bilevel NIV with a standardised EPAP (S-EPAP) of 5cmH2O, and to describe the physiological effects of bilevel NIV during exercise. Other secondary aims were to determine the effects of participant characteristics, such as resting lung hyperinflation and degree of DH during exercise, on the response to bilevel NIV during exercise (isotime IC and endurance time). 3. Explore the perceptions of using bilevel NIV during exercise in patients with severe COPD who were naive to NIV and evaluate the relationships between individual perceptions of bilevel NIV during exercise and both baseline characteristics and exercise outcomes with bilevel NIV during exercise. The study also aimed to identify potential barriers and facilitators to using bilevel NIV during exercise. This study in Chapter 2 validated the use of a portable CPET system (K4b2, Cosmed, Italy) to measure metabolic and ventilatory variables when bilevel NIV was used during exercise. Benchtop simulation of exercise with the CPET system with and without bilevel NIV showed that ventilatory variables for volume and respiratory rate were not different with compared to without bilevel NIV however accurate measurement of oxygen uptake (V̇O2) during exercise tests was only possible after compensation for pressure with bilevel NIV. Accurate measures of V̇O2 aid the interpretation of results as a reduction in isotime V̇O2 could suggest a reduced work of breathing in people with COPD. This system was used in the randomised crossover clinical trial in Chapter 3. The randomised crossover trial in Chapter 3 of bilevel NIV using either standardised expiratory positive airway pressure (EPAP) of 5cmH2O or titrated EPAP compared to no NIV used the CPET system and compensation equation established in Chapter 2 for measurement of V̇O2 to report the metabolic and ventilatory variables during exercise. The study reported that bilevel NIV reduced DH at isotime and increased exercise endurance time in people with severe to very-severe COPD. Compared to no NIV, there was a statistically significant greater isotime IC with a standardized EPAP (S-EPAP) (MD [95% Confidence Interval (CI)] = 0.19 L [0.10-0.28]), and the change with titrated EPAP (T-EPAP) (0.22 L [0.13-0.32]) exceeded the minimum clinically important difference (MCID) of 200mL for change in IC during endurance cycle exercise. The increase in endurance time during a cycle endurance test with bilevel NIV and S-EPAP (153 s [24- 280]) or T-EPAP (145 s [28-259]), compared to exercise without bilevel NIV was above the MCID of 105 seconds established in exercise training programs. At isotime, in addition to reduced DH, dyspnoea, RR, transcutaneous carbon dioxide (TcCO2) and V̇O2 were also reduced while oxygen saturation (SpO2) and muscle oxygen saturation (SmO2) were increased which may be suggestive of an unloading of the work of breathing. Bilevel NIV may be a useful adjunct to reduce DH and improve exercise tolerance in patients with severe to very-severe COPD. While a method of setting an individualised (titrated) EPAP (4.0 ± 1.2 cmH2O) was successful at increasing IC in the initial titration test, the T-EPAP was very similar to the S-EPAP of 5cmH2O and was not more effective at decreasing DH during exercise or increasing exercise duration. In clinical practice, an EPAP of 5cmH2O appears to be a suitable expiratory pressure to increase exercise time and reduce DH during exercise. Correlations between participants’ baseline characteristics and exercise test outcomes revealed that those with greater resting hyperinflation (residual volume/total lung capacity (RV/TLC)% predicted) had a greater improvement in exercise duration with bilevel NIV compared to those with lower RV/TLC% predicted (r = 0.47) and those with a greater change in IC (or more dynamic hyperinflation) during an incremental peak cycle test had a greater reduction in isotime DH with bilevel NIV during the endurance exercise test (r=0.43). The research supports the use of bilevel NIV during exercise in people with severe to very-severe COPD with resting and/or dynamic hyperinflation, regardless of prior NIV experience, and suggests that bilevel NIV during exercise could be beneficial for more people than just those already using nocturnal NIV. Therefore, it may be useful to measure static lung volumes when considering and selecting people most likely to respond to using bilevel NIV during exercise. In the study in Chapter 4, questionnaires and interviews were used to document participants’ responses during the clinical trial reported in Chapter 3. Participants were naïve to NIV, and all participants revealed generally positive perceptions of bilevel NIV during exercise. Those participants who had an improved exercise endurance time or improved isotime IC from the study in Chapter 3, responded that they could feel the benefit and felt more comfortable using bilevel NIV during exercise than those who benefitted less. Comparing and correlating the physiological responses to the perceptions of NIV during exercise revealed a moderate correlation suggesting people with more resting hyperinflation (ρ = 0.603, p = 0.02) or who hyperinflated more during an incremental exercise test (ρ = 0.488, p = 0.03) were more likely to feel more comfortable with NIV during exercise. During the interviews participants mentioned asynchrony with the ventilator as an issue which has also been evident in previous trials in people with COPD and commented on the full-face mask as a source of possible discomfort as it impeded actions such as swallowing, coughing, and talking. While there was no order effect in the primary quantitative outcomes from the tests in Chapter 3, just over half of the participants (10/19) selected the second test with NIV as their preferred test citing an increase in familiarity and comfort with the device and interface. However, participants highlighted challenges that need to be overcome before they would consider NIV a useful tool at home or during independent exercise training sessions, such as the size and portability of the device and the complexity of managing and using the ventilator, circuit, and interface for independent activity. A summary of the main findings of the studies within this thesis is presented in Chapter 5. Clinical implications, limitations and suggestions for future research are also discussed in this chapter. Overall, the studies in this thesis showed that it is possible to reliably measure ventilatory variables of VT and RR as well as the metabolic variables of V̇CO2 and V̇O2 using a formula that accounted for the effects of pressure on gas density when using a commercially available CPET system (K4b2, Cosmed, Italy) with bilevel NIV compared to measurements without bilevel NIV. In patients with severe to very severe COPD with resting hyperinflation and DH during exercise, bilevel NIV when compared to exercise without NIV, reduced DH, increased exercise endurance time, and reduced exertional dyspnoea. The level of DH during an incremental maximum test and RV/TLC% predicted correlated with improvements in IC and endurance time with bilevel NIV compared to without suggesting bilevel NIV with an EPAP of around 5 cmH2O may be a beneficial adjunct to exercise training in patients with severe COPD who have clinically significant resting hyperinflation and/or DH during exercise. People with severe to very-severe COPD generally had positive perceptions of the use of bilevel NIV during exercise for the first time and regarded bilevel NIV as being an effective tool to reduce breathlessness during exercise and increase exercise endurance. Participants who perceived a greater improvement with bilevel NIV during exercise were more likely to have an actual increase in exercise duration with bilevel NIV during exercise compared to exercise without bilevel NIV and those with higher RV/TLC% predicted were more likely to feel comfortable with bilevel NIV during exercise than those with lower RV/TLC% predicted. The research in this thesis supports the use of bilevel NIV to assist exercise in people with severe to very-severe COPD and hyperinflation.