Median VO2 Research Articles

Correlation between preoperative cardiopulmonary exercise testing and six-minute walk test, five-times sit to stand test and Short Form-36 physical component score in patients undergoing cytoreductive surgery

IntroductionAssessment of preoperative function is important for determining fitness for surgery, preoperative optimisation and predicting postoperative morbidity in patients undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC). This study explored correlations between preoperative cardiopulmonary exercise testing (CPET) variables, and six-minute walk test (6MWT), five-times sit to stand test (5STS) and Short Form-36 (SF-36) physical component score in patients scheduled for elective CRS-HIPEC. MethodsThis study included patients who underwent preoperative CPET, 6MWT, 5STS and responded to the SF-36 survey prior to elective CRS-HIPEC at Royal Prince Alfred Hospital in Sydney. CPET was performed using a cycle ergometer and measured peak oxygen uptake (VO2 peak) and anaerobic threshold (AT). The associations between preoperative CPET variables and preoperative 6MWT, 5STS and SF-36 were assessed using correlation test. ResultsA total of 133 patients scheduled for elective CRS-HIPEC were included in this study. The median VO2, AT and VE/VCO2 were 20.3 [6.5] ml/kg/min, 13.1 [4.9] ml/kg/min and 29 [4.5], respectively. The median 6MWT, 5STS and SF-36 physical component score were 525 m, 9.2 s and 50.2, respectively. CPET variables were significantly correlated with 6MWT (VO2 r = 0.51; AT r = 0.35; VE/VCO2 r = −0.25; p < 0.01), 5STS (VO2 r = −0.32; AT r = −0.27; VE/VCO2 r = 0.24; p < 0.01) and SF-36 (VO2 r = 0.42; AT r = 0.38; VE/VCO2 r = −0.23; p < 0.01). Conclusions6MWT, 5STS and SF-36 are at best moderately correlated with CPET variables, which suggests that these tests may serve as adjuncts rather than a replacement to CPET in the clinical setting.

Efectividad de un programa multidisciplinario para el manejo de la obesidad: cambio en la calidad de vida y en los parámetros clínicos, fisiológicos y antropométricos

IntroductionObesity is a disease that has become a major public health concern. The objective of this research was to analyze the changes in the quality of life and in clinical, physiological, and anthropometric parameters in patients with obesity, belonging to a multidisciplinary program for weight loss. Materials and methodsObservational retrospective cohort study that included obese patients in a multidisciplinary program. The comparison of quantitative variables at admission and discharge from the program was performed with the Wilcoxon signed rank test, while the qualitative variables were compared with the McNemar test. Statistical analysis was performed in the STATA V.15 program. Results323 patients were analyzed; it was shown that the median weight decreased 4.4 kg (p < 0.001). Adherence to physical activity increased from 30% (n = 97) to 90% (n = 289) (p < 0.001). Similarly, the median VO2 max increased from 23.6 (IQR 19.7-30.4) on admission to 32.9 (IQR 27.8-38) on discharge. Regarding quality of life, self-care was one of the dimensions with the greatest impact during the program, with a decrease in the report of extreme difficulties from 17.7% to 0.3%. Likewise, the visual analogue scale (VAS) increased the median from 50 (RIC 50-70) to 80 (RIC 70-90) (p < 0.001). ConclusionThe multidisciplinary approach to obesity offers a comprehensive approach to the patient, impacting not only physical, but also psychological and emotional aspects of the problem, improving her quality of life.

Association of an Increased Abnormal Mitochondria Ratio in Cardiomyocytes with a Prolonged Oxygen Uptake Time Constant during Cardiopulmonary Exercise Testing of Patients with Non-ischemic Cardiomyopathy.

Objective The cardiac function, blood distribution, and oxygen extraction in the muscles as well as the pulmonary function determine the oxygen uptake (VO2) kinetics at the onset of exercise. This factor is called the VO2 time constant, and its prolongation is associated with an unfavorable prognosis for heart failure (HF). The mitochondrial function of skeletal muscle is known to reflect exercise tolerance. Morphological changes and dysfunction in cardiac mitochondria are closely related to HF severity and its prognosis. Although mitochondria play an important role in generating energy in cardiomyocytes, the relationship between cardiac mitochondria and the VO2 time constant has not been elucidated. Methods We calculated the ratio of abnormal cardiac mitochondria in human myocardial biopsy samples using an electron microscope and measured the VO2 time constant during cardiopulmonary exercise testing. The VO2 time constant was normalized by the fat-free mass index (FFMI). Patients Fifteen patients with non-ischemic cardiomyopathy (NICM) were included. Patients were divided into two groups according to their median VO2 time constant/FFMI value. Results Patients with a low VO2 time constant/FFMI value had a lower abnormal mitochondria ratio than those with a high VO2 time constant/FFMI value. A multiple linear regression analysis revealed that the ratio of abnormal cardiac mitochondria was independently associated with a high VO2 time constant/FFMI. Conclusions An increased abnormal cardiac mitochondria ratio might be associated with a high VO2 time constant/FFMI value in patients with NICM.

Metabolic Manipulation and Therapeutic Hypothermia.

Hypothermia has multiple physiological effects, including decreasing metabolic rate and oxygen consumption (VO2). There are few human data about the magnitude of change in VO2 with decreases in core temperature. We aimed to quantify to magnitude of reduction in resting VO2 as we reduced core temperature in lightly sedated healthy individuals. After informed consent and physical screening, we cooled participants by rapidly infusing 20 mL/kg of cold (4°C) saline intravenously and placing surface cooling pads on the torso. We attempted to suppress shivering using a 1 mcg/kg intravenous bolus of dexmedetomidine followed by titrated infusion at 1.0 to 1.5 μg/(kg·h). We measured resting metabolic rate VO2 through indirect calorimetry at baseline (37°C) and at 36°C, 35°C, 34°C, and 33°C. Nine participants had mean age 30 (standard deviation 10) years and 7 (78%) were male. Baseline VO2 was 3.36 mL/(kg·min) (interquartile range 2.98-3.76) mL/(kg·min). VO2 was associated with core temperature and declined with each degree decrease in core temperature, unless shivering occurred. Over the entire range from 37°C to 33°C, median VO2 declined 0.7 mL/(kg·min) (20.8%) in the absence of shivering. The largest average decrease in VO2 per degree Celsius was by 0.46 mL/(kg·min) (13.7%) and occurred between 37°C and 36°C in the absence of shivering. After a participant developed shivering, core body temperature did not decrease further, and VO2 increased. In lightly sedated humans, metabolic rate decreases around 5.2% for each 1°C decrease in core temperature from 37°C to 33°C. Because the largest decrease in metabolic rate occurs between 37°C and 36°C, subclinical shivering or other homeostatic reflexes may be present at lower temperatures.

Impact of pectus excavatum on pulmonary function and exercise capacity in patients treated with 3D custom-made silicone implants

Pectus excavatum (PE) is the most common congenital chest wall deformity, whose cardiopulmonary consequences are controversial. PE surgery is in our experience usually performed for aesthetic reasons. The aim of this study was to evaluate the impact of PE on respiratory function and exercise capacity in patients with PE before patient-specific silicone implant correction. This monocentric prospective study conducted at Toulouse University Hospital included sixty patients scheduled for custom-made silicone implants correction. Respiratory function (pulmonary function tests (FPTs)) and exercise capacity (VO2 max) were measured before surgery. Before surgery, no (0/60) restrictive lung disease was detected, with a mean total lung capacity (TLC) of 98.5% of predicted value (IC 95%; 80.4-137). Median VO2 max (n=56) was normal (89% predicted), with no cardiac limitation. In this cohort, PE had no impact on respiratory function nor exercise capacity. In patients without cardiac or respiratory effects of PE, silicone implants should be considered the preferred approach as it adequately addressed patients' main complaint of low self-esteem.

Are there any long-term cardio-pulmonary limitations of hospitalized Covid-19 patients?

Abstract Background The Covid-19 pandemic has affected our lives for over a year and almost 500.000 people in Austria have been infected. Although many of them only had low or mild symptoms some had to be treated in the hospital. Even months after their infection some patients complain about fatigue, exercise intolerance and dyspnoea. The aim of this study was to perform a follow-up cardiopulmonary exercise test (CPET) on those patients, at 6 months after their hospitalization to find out if there are long-term cardio-pulmonary limitations (CPL) of Covid-19. We also wanted to check if there is any difference in outcome and CPL between patients who received oxygen therapy vs. without oxygen therapy. Methods 40 patients were included into this study (16 women = 40%; 24 men = 60%). All patients were hospitalized during their infection with Covid-19 (5 patients at ICU) and underwent CPET 6±2 month after discharge. 20 patients (50%) received oxygen therapy or ventilation during their hospitalization. CPET data were assessed at rest, during exercise and at recovery. Blood parameters including NT-pro BNP were collected and an interview and examination were performed. CPL was defined as VO2% of Predicted ≤84%, VE/CO2 Slope ≥34 and RER at peak of exercise ≥1.1. Results Median age of all patients was 46 years [interquartile range (IQR): 35.3–55.8], median BMI was 26.0 m2/kg [IQR: 23.0–29.0] and the median NTproBNP was 53.1 pg/mL [IQR: 24.0–95.6]. When comparing the two groups, we found higher percentage of CPL in patients who received oxygen therapy during their hospitalization (10% with oxygen vs. 5% without oxygen). Notably, the number of patients with a BMI ≥25 m2/kg was higher in the oxygen therapy group than in those without oxygen (80% vs. 45%). The median BMI without oxygen therapy was 24.0 [IQR: 20.3–26.8] vs. 29.0 [IQR: 25.0–31.0] with oxygen therapy (p=0.004). There were no significant differences in NT-proBNP levels (p=0.545). The median VO2% of predicted was 88.0% [72.5–98.0] without oxygen therapy vs. 84.5% [IQR: 70.8–91.8] with oxygen therapy (p=0.289), the median HR percentage of predicted was 92.5% [IQR: 85.5–97.8] without oxygen therapy vs. 94.5% [IQR: 88.3–103.5] with oxygen therapy (p=0.478), the median physical performance in watt in patients without oxygen therapy was 130.0 [IQR: 108.5–197.5] vs. 135.0 [IQR: 97.0–188.3] with oxygen therapy (p=0.820). Conclusion The findings of our study did not show any statistically significant difference in long-term CPL between patients who received oxygen therapy vs. those who didn't. Therefore, other causes of the exercise intolerance and dyspnoea have to be discussed multidisciplinary. Subclinical CPL in the absence of significant clinical symptoms represent a concern after a Covid-19 infection. Overall, 7.5% of our patients showed CPL although those patients didn't have any clinical symptoms. Therefore, CPET is a good method to discover asymptomatic patients with CPL. Funding Acknowledgement Type of funding sources: None.

Does COVID-19 Affect the Exercise Capacity of Non-hospitalized Patients?

ObjectiveTo determine whether non-hospitalized adults post COVID-19 have impaired exercise capacity.DesignRetrospective analysis.SettingCardiovascular outpatients unit in Instituto Cardiovascular de Rosario, Argentina.PatientsEighty non-hospitalized patients post-infection by COVID-19.InterventionsParticipants completed an ergometry pre and post COVID-19 infection.Main outcome measuresThe study's main variables were the metabolic equivalents of task (METs) and the indirect peak oxygen consumption (VO2 peak).ResultsThe median of METs was 11.7 (9.4-14.8) and 11.7 (11-11.7) in pre and post ergometry, respectively, (p = 0.022). The median VO2 (mL/Kg/min) was 21857 (16938-32761) and 21699 (17004-26467) in pre and post ergometry, respectively, without significant differences.ConclusionsWe found slight differences in maximal physical capacity evaluated through exercise testing in non-hospitalized patients by COVID-19.

Using a quick timed‐up‐and‐go test to predict surgical risk

AbstractBackgroundCardiorespiratory fitness (CRF) has important implications for post‐operative recovery. The timed‐up‐and‐go (TUG) test is a cheap and simple method to assess a patient's functional performance; although how well TUG correlates with results of a cardiopulmonary exercise test (CPET), the gold standard measure of CRF is unknown. Therefore, the aim of this study was to assess the correlation between CPET‐derived parameters of CRF and TUG times in a group of older adults.MethodsNinety‐eight independent community dwelling older adults [mean age: 72 years (range: 61–86), mean body mass index: 26.3 ± 3.1 kg/m2, 54 male] were recruited to this study; completing 180 CPET and TUG testing sessions over a 28 month period. The correlation between CPET‐derived CRF parameters and TUG time was assessed, and receiver operating characteristic curve analysis was performed to determine clinically useful cut‐off points in TUG time.ResultsMedian TUG time was 7.1 s [interquartile range (IQR): 4–8.5], median VO2 peak was 24.4 mL/kg/min (IQR: 20.2–29.2), and the median anaerobic threshold (AT) was 13.4 mL/kg/min (IQR: 8.6–16.5). There was a statistically significant negative correlation between TUG time and AT (r = −0.317, P = &lt;0.0001) and TUG time and VO2 peak (r = −0.4247, P &lt; 0.0001). Receiver operating characteristic curve analysis determined a TUG time of ≥6.5 s to have an 82% sensitivity and 60% specificity to detect an AT &lt;11.0 mL/kg/min, the point at below which perioperative mortality is known to increase.ConclusionsDespite strong evidence for the utility of pre‐operative CPET in stratifying surgical risk, CPET is not universally available. Our finding of a correlation between TUG time and CPET‐derived parameters of CRF (AT/VO2 peak) suggests that TUG may be a useful surrogate in the pre‐operative setting.

Association Between the Oxygen Consumption: Lactate Ratio and Survival in Critically Ill Patients With Sepsis.

Mitochondrial dysfunction leading to impairment of oxygen extraction, referred to as cytopathic hypoxia, contributes to morbidity in sepsis. Oxygen consumption (VO2) may be a useful measure of the severity of cytopathic hypoxia. We monitored VO2 and carbon dioxide production (VCO2) in septic patients and investigated the association with hospital survival. We retrospectively identified adult (≥18 years) septic patients from a larger prospective observational cohort of critically ill patients on mechanical ventilation. A gas-exchange monitor recorded continuous VO2 and VCO2 for up to 48 h. We then tested the association of median VO2, VCO2, respiratory quotient (RQ), and the VO2:lactate ratio with survival. A total of 46 septic patients were included in the analysis, of whom 28 (61%) survived. Overall median VO2 was not associated with survival (3.72 mL/kg/min [IQR: 3.39, 4.92] in survivors and 3.42 mL/kg/min [IQR: 2.97, 5.26] in non-survivors, P = 0.12). The overall median VCO2 and RQ were also not associated with survival. Adjusting for age and the presence of shock did not change these results. The VO2:lactate ratio was associated with survival (adjusted OR 2.17 [95% CI 1.12, 4.22] per unit increase in ratio, P = 0.03). The percent change in median VCO2 was 11.6% [IQR: -8.2, 28.7] in survivors compared with -8.3% [IQR: -18.0, 4.7] in non-survivors (P = 0.03). The percent changes in median VO2 and RQ were not different between groups. The VO2:lactate ratio was significantly higher in survivors, while there was no association between median VO2 alone and survival. There was a significant difference in change in VCO2 over time between survivors and non-survivors.

Hypermetabolism and Coronavirus Disease 2019.

BackgroundHypermetabolism has been described in stress states such as trauma, sepsis, acute respiratory distress syndrome, and severe burn injuries. We hypothesize that patients with Coronavirus disease 2019 (COVID‐19) may develop a hypermetabolic state, which may be a major contributing factor to the extraordinary ventilatory and oxygenation demands in patients with COVID‐19.MethodResting energy expenditure (REE), carbon dioxide production (VCO2), and oxygen consumption (VO2) were measured by indirect calorimetry on 7 critically ill patients with COVID‐19.ResultsThe median measured REE was 4044 kcal/d, which was 235.7% ± 51.7% of predicted. The median VCO2 was 452 mL/min (range, 295–582 mL/min), and the median VO2 was 585 mL/min (range, 416–798 mL/min).ConclusionCritically ill patients with COVID‐19 are in an extreme hypermetabolic state. This may explain the high failure rates for mechanical ventilation for these patients and highlights the potential need for increased nutrition requirements for such patients.

Prevention of Long-term Adverse Health Outcomes With Cardiorespiratory Fitness and Physical Activity in Childhood Acute Lymphoblastic Leukemia Survivors.

Most childhood acute lymphoblastic leukemia (ALL) survivors develop chronic treatment-related adverse effects several years after the end of therapy. A regular practice of physical activity and a good cardiorespiratory fitness have the potential to reduce the risk of chronic disease and improve quality of life. The aim of this study was to evaluate in a cohort of ALL survivors, the association between a good cardiorespiratory fitness or the respect of physical activity guidelines and major long-term health outcomes. In total, 247 ALL survivors underwent a cardiopulmonary exercise test, completed a physical activity questionnaire and a battery of clinical examinations. We calculated the odds ratio to obtain the preventive fraction (PF) to evaluate the effects of the cardiorespiratory fitness and physical activity levels on health outcomes (ie, obesity, metabolic health, cardiac health, cognitive health and mood, bone health). Despite their young age, 88% of the participants presented at least one adverse health outcome, and 46% presented ≥3. Their cardiorespiratory fitness was also lower than expected with a median VO2 peak reaching 84% of the predicted value. In the analyses using cardiorespiratory fitness, statistically significant PFs were observed for obesity (0.30), low-high-density lipoprotein-cholesterol (0.21) and depression (0.26). In the physical activity level analyses, statistically significant PFs were observed for obesity, depression, and low bone mineral density, with a PF of 0.55, 0.81, and 0.60, respectively. Our results indicate that a good cardiorespiratory fitness and physical activity level induced a preventive action for most health outcomes studied and was associated with a lower late adverse effects prevalence in ALL survivors.