Computer-based system for analysis of respiratory responses to exercise

1977 ◽  
Vol 42 (6) ◽  
pp. 968-975 ◽  
Author(s):  
D. H. Pearce ◽  
H. T. Milhorn ◽  
G. H. Holloman ◽  
W. J. Reynolds
Keyword(s):  
Carbon Dioxide ◽  
Respiratory Exchange Ratio ◽  
Minute Ventilation ◽  
Type System ◽  
Work Load ◽  
Magnetic Type ◽  
Computer Based ◽  
End Tidal ◽  
Good Agreement

A computer-based system for the determination of tidal volume, respiratory frequency, minute ventilation, oxygen transfer, carbon dioxide transfer, respiratory exchange ratio, end-tidal oxygen, end-tidal carbon dioxide, and heart rate is presented. These variables are first determined on a breath-by-breath basis from data (expired carbon dioxide and oxygen fractions, airflow, and ECG) prerecorded on an FM magnetic type system. The breath-by-breath data are then averaged for each experimental run in 5-s increments. The 5-s increment data from a group of subjects can then be averaged and the SEM determined at prescribed periods of time. For the study of individual respiratory transient we found the 5-s increment data to be more useful than the breath-by-breath data because it has a lesser degree of fluctuation. The system is especially adapted to careful observation of the responses within the first few seconds of a change in work load. Appropriate computer programs are discussed. The results of several experiments are compared with data from other sources and found to be in good agreement.

Dynamic and steady-state respiratory responses to bicycle exercise

1977 ◽  
Vol 42 (6) ◽  
pp. 959-967 ◽  
Author(s):  
D. H. Pearce ◽  
H. T. Milhorn
Keyword(s):  
Carbon Dioxide ◽  
Minute Ventilation ◽  
Work Load ◽  
Normal Male ◽  
Clear Cut ◽  
Ventilatory Responses ◽  
Delay Times ◽  
End Tidal ◽  
Repeated Runs ◽  
Respiratory Responses

The transient respiratory responses of 10 normal male volunteers to step changes in work load from 0 to 300, 600, and 800 kpm/min were determined by breath-by-breath analysis for tidal volume, minute ventilation, respiratory frequency, end-tidal oxygen and carbon dioxide tensins, oxygen uptake, carbon dioxide elimination, respiratory exchange ratio, and heart rate. Ten experiments were averaged on a 5-s interval basis. Quantitative measures of the dynamics (delay times, half-times, times to peaks, times to plateaus, and plateau amplitudes) are presented. These parameters generally vary with work load and reflect the speed of response of various components of the system. Rapid ventilatory responses were seen at the initiation and termination of exercise; however, they required up to 32.5 s for full development. Repeated runs on three subjects at 600 kpm/min indicate that the experiments are grossly repeatable. The data, at the initiation of exercise, are consistent with the concept of cardiodynamic hyperpnea while the results are not as clear-cut at the termination of exercise.

Ventilatory and gas exchange responses to cycling with sinusoidally varying pedal rate

1978 ◽  
Vol 44 (1) ◽  
pp. 97-103 ◽  
Author(s):  
R. Casaburi ◽  
B. J. Whipp ◽  
K. Wasserman ◽  
S. N. Koyal
Keyword(s):  
Carbon Dioxide ◽  
Minute Ventilation ◽  
Small Variation ◽  
Work Load ◽  
Cycle Ergometer ◽  
Carbon Dioxide Tension ◽  
Ventilatory Responses ◽  
Constant Work Rate ◽  
Co2 Flow ◽  
End Tidal

To investigate factors controlling ventilation under conditions where the applied work load remains constant, but where hypothesized proprioceptive influences would be expected to vary, five subjects exercised at a constant work rate of 50 W on a cycle ergometer at pedaling rates which varied sinusoidally between 40 and 80 rpm. Each subject exercised continuously for 30 min at each of five sinusoidal periods. Minute ventilation (VE), carbon dioxide output (VCO2), oxygen uptake (VO2), and heart rate were computed breath-by-breath and amplitude and phase relations were extracted. We observed small fluctuations in VCO2 and VO2 engendered by varying metabolic requirements of moving the legs at varying rates. VE fluctuations were closely in phase with VCO2 and the amplitudes of the fluctuations were highly significantly correlated (r = 0.83, P less than 0.001); consequently end-tidal carbon dioxide tension fluctuations were small. Variation of pedaling rate, therefore, did not produce a ventilatory response independent of the effect of VCO2. The ventilatory responses to these forcings are inconsistent with an appreciable role for neurally mediated influences from the exercising limbs and provide further evidence that the exercise hyperpnea is linked to CO2 flow to the central circulation.

Decreased Carbon Dioxide Sensitivity in Infants of Substance-Abusing Mothers

PEDIATRICS ◽  
1995 ◽  
Vol 95 (6) ◽  
pp. 864-867
Author(s):  
Janet G. Wingkun ◽  
Janet S. Knisely ◽  
Sidney H. Schnoll ◽  
Gary R. Gutcher
Keyword(s):  
Carbon Dioxide ◽  
Tidal Volume ◽  
Minute Ventilation ◽  
Demographic Data ◽  
Substance Abusing ◽  
Quiet Sleep ◽  
Co2 Level ◽  
The Difference ◽  
End Tidal ◽  
Drug Free

Objective. To determine whether there is a demonstrable abnormality in control of breathing in infants of substance-abusing mothers during the first few days of life. Methods. We enrolled 12 drug-free control infants and 12 infants of substance abusing mothers (ISAMs). These infants experienced otherwise uncomplicated term pregnancies and deliveries. The infants were assigned to a group based on the results of maternal histories and maternal and infant urine toxicology screens. Studies were performed during quiet sleep during the first few days of life. We measured heart rate, oxygen saturations via a pulse oximeter, end-tidal carbon dioxide (ET-CO2) level, respiratory rate, tidal volume, and airflow. The chemoreceptor response was assessed by measuring minute ventilation and the ET-CO2 level after 5 minutes of breathing either room air or 4% carbon dioxide. Results. The gestational ages by obstetrical dating and examination of the infants were not different, although birth weights and birth lengths were lower in the group of ISAMs. Other demographic data were not different, and there were no differences in the infants' median ages at the time of study or in maternal use of tobacco and alcohol. The two groups had comparable baseline (room air) ET-CO2 levels, respiratory rates, tidal volumes, and minute ventilation. When compared with the group of ISAMs, the drug-free group had markedly increased tidal volume and minute ventilation on exposure to 4% carbon dioxide. These increases accounted for the difference in sensitivity to carbon dioxide, calculated as the change in minute ventilation per unit change in ET-CO2 (milliliters per kg/min per mm Hg). The sensitivity to carbon dioxide of control infants was 48.66 ± 7.14 (mean ± SE), whereas that of ISAMs was 16.28 ± 3.14. Conclusions. These data suggest that ISAMs are relatively insensitive to challenge by carbon dioxide during the first few days of life. We speculate that this reflects an impairment of the chemoreceptor response.

Ventilatory responses to carbon dioxide at low and high levels of oxygen are elevated after episodic hypoxia in men compared with women

2004 ◽  
Vol 97 (5) ◽  
pp. 1673-1680 ◽  
Author(s):  
Chris Morelli ◽  
M. Safwan Badr ◽  
Jason H. Mateika
Keyword(s):  
Carbon Dioxide ◽  
Ventilatory Response ◽  
Minute Ventilation ◽  
High Oxygen ◽  
Set Point ◽  
Ventilatory Responses ◽  
Episodic Hypoxia ◽  
Before And After ◽  
Oxygen Gas ◽  
End Tidal

We hypothesized that the acute ventilatory response to carbon dioxide in the presence of low and high levels of oxygen would increase to a greater extent in men compared with women after exposure to episodic hypoxia. Eleven healthy men and women of similar race, age, and body mass index completed a series of rebreathing trials before and after exposure to eight 4-min episodes of hypoxia. During the rebreathing trials, subjects initially hyperventilated to reduce the end-tidal partial pressure of carbon dioxide (PetCO2) below 25 Torr. Subjects then rebreathed from a bag containing a normocapnic (42 Torr), low (50 Torr), or high oxygen gas mixture (150 Torr). During the trials, PetCO2 increased while the selected level of oxygen was maintained. The point at which minute ventilation began to rise in a linear fashion as PetCO2 increased was considered to be the carbon dioxide set point. The ventilatory response below and above this point was determined. The results showed that the ventilatory response to carbon dioxide above the set point was increased in men compared with women before exposure to episodic hypoxia, independent of the oxygen level that was maintained during the rebreathing trials (50 Torr: men, 5.19 ± 0.82 vs. women, 4.70 ± 0.77 l·min−1·Torr−1; 150 Torr: men, 4.33 ± 1.15 vs. women, 3.21 ± 0.58 l·min−1·Torr−1). Moreover, relative to baseline measures, the ventilatory response to carbon dioxide in the presence of low and high oxygen levels increased to a greater extent in men compared with women after exposure to episodic hypoxia (50 Torr: men, 9.52 ± 1.40 vs. women, 5.97 ± 0.71 l·min−1·Torr−1; 150 Torr: men, 5.73 ± 0.81 vs. women, 3.83 ± 0.56 l·min−1·Torr−1). Thus we conclude that enhancement of the acute ventilatory response to carbon dioxide after episodic hypoxia is sex dependent.

Effects of elevated oxygen and carbon dioxide partial pressures on respiratory function and cognitive performance

2014 ◽  
Vol 117 (4) ◽  
pp. 406-412 ◽  
Author(s):  
Matthew Gill ◽  
Michael J. Natoli ◽  
Charles Vacchiano ◽  
David B. MacLeod ◽  
Keita Ikeda ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Respiratory Function ◽  
Vision Loss ◽  
Minute Ventilation ◽  
Cycle Ergometer ◽  
Hyperbaric Chamber ◽  
Tunnel Vision ◽  
Partial Pressures ◽  
Ergometer Exercise ◽  
End Tidal

Hyperoxia during diving has been suggested to exacerbate hypercapnic narcosis and promote unconsciousness. We tested this hypothesis in male volunteers (12 at rest, 10 at 75 W cycle ergometer exercise) breathing each of four gases in a hyperbaric chamber. Inspired Po2 (PiO2) was 0.21 and 1.3 atmospheres (atm) without or with an individual subject's maximum tolerable inspired CO2 (PiO2 = 0.055–0.085 atm). Measurements included end-tidal CO2 partial pressure (PetCO2), rating of perceived discomfort (RPD), expired minute ventilation (V̇e), and cognitive function assessed by auditory n-back test. The most prominent finding was, irrespective of PetCO2, that minute ventilation was 8–9 l/min greater for rest or exercise with a PiO2 of 1.3 atm compared with 0.21 atm ( P < 0.0001). For hyperoxic gases, PetCO2 was consistently less than for normoxic gases ( P < 0.01). For hyperoxic hypercapnic gases, n-back scores were higher than for normoxic gases ( P < 0.01), and RPD was lower for exercise but not rest ( P < 0.02). Subjects completed 66 hyperoxic hypercapnic trials without incident, but five stopped prematurely because of serious symptoms (tunnel vision, vision loss, dizziness, panic, exhaustion, or near syncope) during 69 normoxic hypercapnic trials ( P = 0.0582). Serious symptoms during hypercapnic trials occurred only during normoxia. We conclude serious symptoms with hyperoxic hypercapnia were absent because of decreased PetCO2 consequent to increased ventilation.

Indirect calorimetry with a hood: flow requirements, accuracy, and minute ventilation measurement

1993 ◽  
Vol 74 (1) ◽  
pp. 485-491 ◽  
Author(s):  
B. E. Pennock ◽  
M. Donahoe
Keyword(s):  
Water Vapor ◽  
Indirect Calorimetry ◽  
Respiratory Exchange Ratio ◽  
Minute Ventilation ◽  
Co2 Concentration ◽  
Patient Comfort ◽  
Co2 Production ◽  
O2 Concentration ◽  
Expired Gas

Flow-dilution-based hood systems for indirect calorimetry eliminate the conventional mouthpiece or mask of sealed-circuit systems allow measurements with improved patient comfort. This feature is particularly relevant when measurements are made over long periods of time or are repeated often. The flow of air pulled through the hood into the calorimeter in these systems is necessary to clear CO2 from inside the hood. The errors in these systems are greater than those in the sealed-circuit systems and are proportional to the flow. We show that the CO2 concentration within the hood at steady state does not depend on hood size. We describe the accuracy in determination of O2 consumption (VO2), CO2 production, and respiratory exchange ratio with a hood system as a function of the accuracy of the O2 and CO2 analyzers and the water vapor in collected gas. For example, we show that if there is a 1% error in O2 concentration, the percent error in VO2 changes from 5% in a sealed circuit to 51% when a cleansing flow of 50 l/min is introduced. The error in VO2 caused by a 5% error in CO2 determination is 10.6% at this cleansing flow. Removal of 90% of the water vapor (instead of 100%) before analysis of the expired gas introduces a 15.8% error in VO2. By use of the equations described, the accuracy of any measurement system can be determined. In addition, we demonstrate that the measurement of ventilation, usually lost in a hood system, can be preserved using dual pneumotachographs and a sealed hood.

Difference in Caloric Expenditure in Sitting Versus Standing Desks

2012 ◽  
Vol 9 (7) ◽  
pp. 1009-1011 ◽  
Author(s):  
Christopher Reiff ◽  
Kara Marlatt ◽  
Donald R. Dengel
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Minute Ventilation ◽  
Carbon Dioxide Production ◽  
Caloric Expenditure ◽  
Gas System ◽  
The Hours ◽  
Mathematical Problems ◽  
Healthy Participants

Background:Traditional desks require students to sit; however, recently schools have provided students with nontraditional standing desks. The purpose of this study was to investigate differences in caloric expenditure of young adults while sitting at a standard classroom desk and standing at a nontraditional standing classroom desk.Methods:Twenty (10 male/10 female) young (22.8 ± 1.9 y), healthy participants reported to the laboratory between the hours of 7:00 AM and 2:00 PM following a 12-h fast and 48-h break in exercise. Participants were randomly assigned to perform a series of mathematical problems either sitting at a normal classroom desk or standing at a nontraditional standing desk. Inspired and expired gases were collected for 45-min for the determination of oxygen consumption (VO2), carbon dioxide production (VCO2), and minute ventilation (VE) using a metabolic gas system.Results:There were significant increases from sitting to standing in VO2 (0.22 ± 0.05 vs. 0.28 ± 0.05 L·min−1, P ≤ .0001), VCO2 (0.18 ± 0.05 vs. 0.24 ± 0.050 L·min−1, P ≤ .0001), VE (7.72 ± 0.67 vs. 9.41 ± 1.20 L·min−1, P ≤ .0001), and kilocalories expended per minute (1.36 ± 0.20 kcal/ min, P ≤ .0001 vs. 1.02 ± 0.22 kcal/min, P ≤ .0001).Conclusions:Results indicate a significant increase in caloric expenditure in subjects that were standing at a standing classroom desk compared with sitting at a standard classroom desk.

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