scholarly journals Relationship between ventilatory pattern and peak VO2 and area M regulates the respiratory system during exercise

2020 ◽  
Vol 76 (5) ◽  
pp. 521-528
Author(s):  
Makoto Murata ◽  
Hitoshi Adachi ◽  
Taisuke Nakade ◽  
Yasuyuki Kobayashi ◽  
Piergiuseppe Agostoni
2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
F Gama ◽  
P Freitas ◽  
A Ferreira ◽  
A Durazzo ◽  
C Aguiar ◽  
...  

Abstract Background and aim Limitation of exercise tolerance is one of the cardinal manifestations of heart failure (HF). Cardiopulmonary exercise testing (CPET) provides a thorough assessment of exercise integrative physiology involving the pulmonary, muscular, and oxidative cellular systems. We aimed to identify which data collected during a CPET shows the best prognostic performance with respect to predicting mortality or the need for heart transplantation (HT). Methods Single-centre retrospective cohort study of consecutive HF patients performing a CPET for functional and prognostic HF evaluation from October 1996 till May 2018. Left ventricular ejection fraction was not an exclusion criterion. A Cox model was fit with time to death or heart transplantation (whichever recorded first within 5 years) as the dependent variable and CPET parameters as the independent variables. Both unadjusted and adjusted covariate Cox regressions were performed. ROC curve analysis was used to determine whether the significant variables, as a model, could reliably predict the study endpoint. Results The study population consisted of 513 patients, median age 58 (IQ 16) years, and 74.9% male. The majority had reduced ejection fraction (75.4%), and the most common HF aetiology was ischemic heart disease (55.8%). During the 5-years follow up, 126 patients died and 60 underwent heart transplantation. In unadjusted Cox regression, nearly all CPET variables were significantly associated with the study endpoint. After covariate adjustment, with prior exclusion of redundant variables, three measures remained associated with the study endpoint: peak VO2 consumption (hazard ratio [HR] 0.85; 95% confidence interval [CI], 0.81–0.90); VE/VCO2 slope (HR 1.02; 95% CI, 1.00–1.02); presence of oscillatory ventilatory pattern (HR 3.73; 95% CI, 2.43–5.72). As a model, these 3 variables showed a strong discriminatory ability (c-statistic 0.87; 95% CI, 0.83–0.90) (see figure) for the study endpoint. Figure 1 Conclusion When using the CPET for prognostic stratification of HF patients, the presence of an oscillatory ventilatory pattern, the peak VO2 and the VE/VCO2 slope are the most important tools on which clinicians should focus.


2021 ◽  
Vol 2 (3) ◽  
pp. 73-78
Author(s):  
Robert Chatburn

The Four Truths 1. The truth of confusion 2. The truth of the origin of confusion 3. The truth of the cessation of confusion 4. The truth of the path leading to the cessation of confusion The 10-Fold Path 1. A breath is one cycle of positive flow (inspiration) and negative flow (expiration) defined in terms of the flow-time curve. 2. A breath is assisted if the ventilator does work on the patient. 3. A ventilator assists breathing using either pressure control or volume control based on the equation of motion for the respiratory system. 4. Breaths are classified by the criteria that trigger (start) and cycle (stop) inspiration 5. Trigger and cycle events can be initiated by the patient or the machine. 6. Breaths are classified as spontaneous or mandatory based on both the trigger and cycle events. 7. There are 3 breath sequences: Continuous mandatory ventilation (CMV), Intermittent Mandatory Ventilation (IMV), and Continuous Spontaneous Ventilation (CSV). 8. There are 5 basic ventilatory patterns: VC-CMV, VC-IMV, PC-CMV, PC-IMV, and PC-CSV: 9. Within each ventilatory pattern there are several variations that can be distinguished by their targeting scheme(s). 10. A mode of ventilation is classified according to its control variable, breath sequence, and targeting scheme(s). Keywords: Breath. Trigger, Cycle, Breath sequences, Ventilatory patterns, Mode of ventilation


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5137 ◽  
Author(s):  
Pedro Trevizan-Baú ◽  
Augusto S. Abe ◽  
Wilfried Klein

BackgroundVentilatory parameters have been investigated in several species of Testudines, but few species have had their ventilatory pattern fully characterized by presenting all variables necessary to understand changes in breathing pattern seen under varying environmental conditions.MethodsWe measured ventilation and gas exchange at 25 °C in the semi-aquatic turtleTrachemys scriptaand the terrestrial tortoiseChelonoidis carbonariusunder normoxia, hypoxia, and hypercarbia and furthermore compiled respiratory data of testudine species from the literature to analyze the relative changes in each variable.ResultsDuring normoxia both species studied showed an episodic breathing pattern with two to three breaths per episode, but the non-ventilatory periods (TNVP) were three to four times longer inT. scriptathan inC. carbonarius. Hypoxia and hypercarbia significantly increased ventilation in both species and decreased TNVPand oxygen consumption inT. scriptabut not inC. carbonarius.DiscussionContrary to expectations, the breathing pattern inC. carbonariusdid show considerable non-ventilatory periods with more than one breath per breathing episode, and the breathing pattern inT. scriptawas found to diverge significantly from predictions based on mechanical analyses of the respiratory system. A quantitative analysis of the literature showed that relative changes in the ventilatory patterns of chelonians in response to hypoxia and hyperbarbia were qualitatively similar among species, although there were variations in the magnitude of change.


2016 ◽  
Vol 44 (5) ◽  
pp. 383-395 ◽  
Author(s):  
Nehaarika Kantipudi ◽  
Vivek Patel ◽  
Graham Jones ◽  
Markad V. Kamath ◽  
Adrian R. M. Upton

2020 ◽  
Vol 28 (3) ◽  
pp. 290-299
Author(s):  
Kira A. Ageeva ◽  
Evgenii V. Filippov

Aim. To study the prognostic value of the results of dynamic capnography in the complex assessment of parameters of the respiratory system in 6-minute walk test in patients with chronic heart failure (CHF). Materials and Methods. 73 Patients were examined: the group of study included 48 patients with IIA or IIB stage CHF (mean age 57.94.6 years, 23 men), the control group included 25 practically healthy volunteers (mean age 47.63.5 years, 9 men). The patients were conducted complex determination of parameters of the respiratory system: clinical scaling before and after 6-minute walk test (6MWT), instrumental examinations including spirometry, capnography and pulse oximetry before, during and after physical activity. The analysis of survival was conducted on the basis of the dynamic follow-up of patients within 5 years (60 months). Results. In the analysis of parameters of dyspnea at rest, all the parameters were higher in the group of patients with CHF (р0.05). The distance walked by the patients with CHF in 6 minutes was 488.2390.84 m, which was significantly less than in the control group (815.6053.89 m, р=0.009). Dyspnea as the cause of stoppage/slowing down of walking in 6MWT, was also more often recorded in patients with CHF (93.83.0% and 48.05.1%, р=0.049). Besides, in 6MWT the patients noted: weakness in legs (50.15.0% in the group of CHF and 40.05.0% in the control group, р=0.014), palpitation (29.04.6% and 20.04.1%, respectively, р=0.004). Worsening of dyspnea parameters in 6MWT was more evident in patients with CHF than in the control group (р0.01). In the CHF group, hypocapnic type of ventilation was revealed in 6MWT, analysis of РЕТСО2 trend graphs revealed a wave-like increase in the parameters, the so called periodic breathing (PB). CO2 trend was recorded in CHF group in 58.31.0% of cases (the difference with the control group with р=0.046), the trend of heart rate in 18.80.3% of cases (р=0.027). Cox proportional hazards regression analysis of mortality in patients with CHF showed a prognostic significance of a complex model comprising the following parameters of a patient: body mass index (р=0.005), left ventricular end-diastolic dimension (р=0.034), left ventricular end-systolic dimension (р=0.002), left ventricular ejection fraction (р=0.041), 6MWT distance (р=0.004), desaturation (р=0.009), and the presence of signs of PB during 6MWT (р=0.005). Model coefficients were statistically significant at р0.0001. Conclusions. Dynamic capnography and pulse oximetry allow to identify signs of PB in patients with CHF during 6MWT which may deepen a complex assessment of parameters of the cardio-respiratory system in patients with CHF in order to determine tolerance to physical exercise as well as the effectiveness of the conducted treatment. Complex assessment of survival of patients with CHF showed prognostic significance of the following parameters of a patient: body mass index, left ventricular end-diastolic dimension, left ventricular end-systolic dimension, left ventricular ejection fraction, 6MWT distance, desaturation, PB during 6MWT.


Author(s):  
Dr. Vishal Shamrao Patil ◽  
Dr. (Mrs.) Manisha V. Bhalsing

Lung function tests are useful in assessing the functional status of Respiratory system in both in physiological as well as pathological conditions. These are based on the measurement of volume of air breathed in and out in quite breathing & forced breathing. Air in lungs is classified in to two divisions’ lung volumes & lung capacities. Lung Capacities are the combination of two or more lung volumes. The concept of Rakt Dhatu & Vayu is important in case of respiration because Charaka says that pure blood provides the person with strength, luster & happy life because vital breath follows blood. It represents mechanism of oxygenated & deoxygenated blood & its relation with functioning capacity of Lungs. So In this article attempt has been made to review concepts regarding functions of Rakt Dhatu & Vayu to Establish Lung Function Capacity.


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