A model of locomotor-respiratory coupling in quadrupeds

2009 ◽  
Vol 33 (4) ◽  
pp. 315-318 ◽  
Author(s):  
Mauricio J. Giuliodori ◽  
Heidi L. Lujan ◽  
Whitney S. Briggs ◽  
Stephen E. DiCarlo
Keyword(s):  
Respiratory Function ◽  
Minute Ventilation ◽  
Lung Ventilation ◽  
Student Understanding ◽  
Stride Frequency ◽  
Metabolic Power ◽  
Running Speed ◽  
Mechanical Constraints ◽  
Cyclic Movements ◽  
Wide Range

Locomotion and respiration are not independent phenomena in running mammals because locomotion and respiration both rely on cyclic movements of the ribs, sternum, and associated musculature. Thus, constraints are imposed on locomotor and respiratory function by virtue of their linkage. Specifically, locomotion imposes mechanical constraints on breathing that require the respiratory cycle to be synchronized with gait. Thus, many mammals, including humans, synchronize respiration with the movement of the limbs during locomotion. For example, quadrupeds synchronize locomotor and respiratory cycles at a 1:1 ratio (stride/breath) over a wide range of speeds. Interestingly, quadrupeds maintain an almost constant stride frequency (and therefore respiratory frequency) at different speeds. To increase speed, quadrupeds lengthen their stride. Accordingly, to increase minute ventilation, quadrupeds must increase tidal volume since respiratory rate is coupled with stride frequency. We developed a simple, inexpensive, and easy to build model to demonstrate this concept. A model was chosen because models significantly enhance student understanding. Students are drawn into discussion by the power of learning that is associated with manipulating and thinking about objects. Building and using this model strengthen the concept that locomotor-respiratory coupling provides a basis for the appropriate matching of lung ventilation to running speed and metabolic power.

Abstract 264: Automatic Detection of Ventilations Using the Thoracic Impedance Signal During Lucas Chest Compressions

Circulation ◽  
2019 ◽  
Vol 140 (Suppl_2) ◽  
Author(s):  
Xabier Jaureguibeitia ◽  
Unai Irusta ◽  
Elisabete Aramendi ◽  
Pamela Owens ◽  
Henry E Wang ◽  
...  
Keyword(s):  
Cardiac Arrest ◽  
Minute Ventilation ◽  
Lung Ventilation ◽  
Detection Algorithm ◽  
Ventilation Rate ◽  
Thoracic Impedance ◽  
Chest Compressions ◽  
Signal Processing Algorithm ◽  
Ventilation Rates ◽  
Mechanical Cpr

Introduction: Resuscitation from out-of-cardiac arrest (OHCA) requires control of both chest compressions and lung ventilation. There are few effective methods for detecting ventilations during cardiopulmonary resuscitation. Thoracic impedance (TI) is sensitive to changes in lung air volumes and may allow detection of ventilations but has not been tested with concurrent mechanical chest compressions. Hypothesis: It is possible to automatically detect and characterize ventilations from TI changes during mechanical chest compressions. Methods: A cohort of 420 OHCA cases (27 survivors to hospital discharge) were enrolled in the Dallas-Fort Worth Center for Resuscitation Research cardiac arrest registry. These patients were treated with the LUCAS-2 CPR device and had concurrent TI and capnogram recordings from MRx (Philips, Andover, MA) monitor-defibrillators. We developed a signal processing algorithm to suppress chest compression artifacts from the TI signal, allowing identification of ventilations. We used the capnogram as gold standard for delivered ventilations. We determined the accuracy of the algorithm for detecting capnogram-indicated ventilations, calculating sensitivity, the proportion of true ventilations detected in the TI, and positive predictive value (PPV), the proportion of true ventilations within the detections. We calculated per minute ventilation rate and mean TI amplitude, as surrogate for tidal volume. Statistical differences between survivors and non-survivors were assessed using the Mann-Whitney test. Results: We studied 4331 minutes of TI during CPR. There were a median of 10 (IQR 6-14) ventilations per min and 52 (30-81) ventilations per patient. Sensitivity of TI was 95.9% (95% CI, 74.5-100), and PPV was 95.8% (95% CI, 80.0-100). The median ventilation rates for survivors and non-survivors were 7.75 (5.37-9.91) min -1 and 5.64 (4.46-7.15) min -1 (p<10 -3 ), and the median TI amplitudes were 1.33 (1.03-1.75) Ω and 1.14 (0.77-1.66) Ω (p=0.095). Conclusions: An accurate automatic TI ventilation detection algorithm was demonstrated during mechanical CPR. The relation between ventilation rate during mechanical CPR and survival was significant, but it was not for impedance amplitude.

Hypaxial muscle activity during running and breathing in dogs

2002 ◽  
Vol 205 (13) ◽  
pp. 1953-1967 ◽  
Author(s):  
Stephen M. Deban ◽  
David R. Carrier
Keyword(s):  
Muscle Activity ◽  
Respiratory Function ◽  
Lung Ventilation ◽  
Transversus Abdominis ◽  
Trunk Muscles ◽  
Dual Function ◽  
Intercostal Muscle ◽  
Terrestrial Vertebrates ◽  
Axial Muscles ◽  
External Oblique

SUMMARYThe axial muscles of terrestrial vertebrates serve two potentially conflicting functions, locomotion and lung ventilation. To differentiate the locomotor and ventilatory functions of the hypaxial muscles in mammals, we examined the locomotor and ventilatory activity of the trunk muscles of trotting dogs under two conditions: when the ventilatory cycle and the locomotor cycle were coupled and when they were uncoupled. Patterns of muscle-activity entrainment with locomotor and ventilatory events revealed (i)that the internal and external abdominal oblique muscles performed primarily locomotor functions during running yet their activity was entrained to expiration when the dogs were standing, (ii) that the internal and external intercostal, external oblique thoracic and transversus abdominis muscles performed both locomotor and respiratory functions simultaneously, (iii) that the parasternal internal intercostal muscle performed a primarily respiratory function (inspiration) and (iv) that the deep pectoralis and longissimus dorsi muscles performed only locomotor functions and were not active while the dogs were standing still. We conclude that the dual function of many hypaxial muscles may produce functional conflicts during running. The redundancy and complexity of the respiratory musculature as well as the particular pattern of respiratory—locomotor coupling in quadrupedal mammals may circumvent these conflicts or minimize their impact on respiration.

Ventilation and gas exchange in lizards during treadmill exercise.

1997 ◽  
Vol 200 (20) ◽  
pp. 2629-2639
Author(s):  
T Wang ◽  
D R Carrier ◽  
J W Hicks
Keyword(s):  
Exchange Rate ◽  
Gas Exchange ◽  
Oxygen Uptake ◽  
Minute Ventilation ◽  
Oxygen Demand ◽  
Lung Ventilation ◽  
Iguana Iguana ◽  
Maximal Aerobic Speed ◽  
Gas Exchange Rate ◽  
Treadmill Locomotion

The extent to which lizards ventilate their lungs during locomotion is controversial. Direct measurements of airflow across the nostrils suggest a progressive reduction in tidal volume and minute ventilation with increased running speed, while other studies have demonstrated that arterial PO2 remains constant during exercise. To resolve these conflicting findings, we measured minute ventilation and gas exchange rate in five specimens of Varanus exanthematicus and five specimens of Iguana iguana during treadmill locomotion at speeds between 0.14 and 1.11ms-1 at 35 degrees C. These speeds are much lower than maximal running speeds, but are greater than the maximal aerobic speed. In both species, the ventilatory pattern during locomotion was highly irregular, indicating an interference between locomotion and lung ventilation. In Varanus exanthematicus, treadmill locomotion elicited a six- to eightfold increase in minute ventilation from a pre-exercise level of 102mlkg-1min-1, whereas the rate of oxygen uptake increased approximately threefold (from 3.9 to 12.6mlkg-1min-1). After exercise, both minute ventilation and gas exchange rate decreased immediately. Because minute ventilation increased more than did oxygen consumption, an increase in lung PO2 during exercise is predicted and, thus, Varanus exanthematicus appears effectively to ventilate its lungs to match the increased metabolic rate during locomotion at moderate speed. In Iguana iguana, both minute ventilation and gas exchange rate increased above resting values during locomotion at 0.28ms-1, but both decreased with further increases in locomotor speed. Furthermore, following exercise, both minute ventilation and oxygen uptake rate increased significantly. Iguana iguana, therefore, appears to be unable to match the increased oxygen demand with adequate ventilation at moderate and higher speeds.

scholarly journals A novel accessory respiratory muscle in the American alligator ( Alligator mississippiensis )

2019 ◽  
Vol 15 (7) ◽  
pp. 20190354 ◽  
Author(s):  
Jonathan R. Codd ◽  
Kayleigh A. R. Rose ◽  
Peter G. Tickle ◽  
William I. Sellers ◽  
Robert J. Brocklehurst ◽  
...  
Keyword(s):  
Respiratory Function ◽  
Respiratory Activity ◽  
Lung Ventilation ◽  
Alligator Mississippiensis ◽  
Evolutionary Constraints ◽  
Breathing Frequency ◽  
American Alligator ◽  
Form And Function ◽  
Distress Vocalizations ◽  
And Function

The muscles that effect lung ventilation are key to understanding the evolutionary constraints on animal form and function. Here, through electromyography, we demonstrate a newly discovered respiratory function for the iliocostalis muscle in the American alligator ( Alligator mississippiensis ). The iliocostalis is active during expiration when breathing on land at 28°C and this activity is mediated through the uncinate processes on the vertebral ribs. There was also an increase in muscle activity during the forced expirations of alarm distress vocalizations. Interestingly, we did not find any respiratory activity in the iliocostalis when the alligators were breathing with their body submerged in water at 18°C, which resulted in a reduced breathing frequency. The iliocostalis is an accessory breathing muscle that alligators are able to recruit in to assist expiration under certain conditions.

Cervical spinal cord injury alters the pattern of breathing in anesthetized rats

2001 ◽  
Vol 91 (6) ◽  
pp. 2451-2458 ◽  
Author(s):  
Francis J. Golder ◽  
Paul J. Reier ◽  
Paul W. Davenport ◽  
Donald C. Bolser
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Respiratory Function ◽  
Cervical Spinal Cord ◽  
Minute Ventilation ◽  
Cervical Spinal Cord Injury ◽  
Respiratory Pattern ◽  
Time Intervals ◽  
Cord Injury ◽  
Bilateral Vagotomy

The mechanisms by which chronic cervical spinal cord injury alters respiratory function and plasticity are not well understood. We speculated that spinal hemisection at C2 would alter the respiratory pattern controlled by vagal mechanisms. Expired volume (Ve) and respiratory rate (RR) were measured in anesthetized control and C2-hemisected rats at 1 and 2 mo postinjury. C2 hemisection altered the pattern of breathing at both postinjury time intervals. Injured rats utilized a higher RR and lower Ve to maintain the same minute ventilation as control rats. After bilateral vagotomy, the pattern of breathing in injured rats was not different from controls. The frequency of augmented breaths was higher in injured rats at 2 mo postinjury before vagotomy; however, the Ve of augmented breaths was not different between groups. In conclusion, C2 hemisection alters the pattern of breathing at 1 and 2 mo postinjury via vagal mechanisms.

scholarly journals Changes in respiratory function following the intramuscular administration of etorphine to boer goats (Capra hircus)

2001 ◽  
Vol 72 (3) ◽  
Author(s):  
P.E. Buss ◽  
D.G.A. Meltzer
Keyword(s):  
Respiratory Function ◽  
Minute Ventilation ◽  
Minute Volume ◽  
Capra Hircus ◽  
Physiological Effects ◽  
Physiological Changes ◽  
Respiratory Effects ◽  
Physiological Dead Space ◽  
Boer Goats ◽  
Dead Space Ventilation

The physiological effects on respiratory function of etorphine (M99, Logos Agvet) (30 µg/kg) administered intramuscularly were determined in boer goats. The goats were habituated to the experimental procedures so that respiratory function could be determined while the animals stood quietly at rest. This enabled the physiological changes induced by etorphine to be measured and compared with those obtained before administration of the immobilising drug. The effectiveness of diprenorphine (M5050, Logos Agvet) (3 mg/1 mg etorphine) as an antagonist of the physiological changes induced by the etorphine treatment was also determined. Etorphine depressed respiratory function, which resulted in a decrease in PaO2 and an increase in PaCO2. These changes were limited and occurred as a result of decreases in respiratory minute volume and alveolar minute ventilation caused by a decrease in respiratory rate. The physiological shunt fraction did not change significantly but there was a significant decrease in percentage physiological dead space ventilation. It was not possible to determine how effectively diprenorphine reversed the respiratory effects due to etorphine.

scholarly journals Sprint and endurance power and ageing: an analysis of master athletic world records

2008 ◽  
Vol 276 (1657) ◽  
pp. 683-689 ◽  
Author(s):  
Jörn Rittweger ◽  
Pietro Enrico di Prampero ◽  
Nicola Maffulli ◽  
Marco V Narici
Keyword(s):  
Athletic Performance ◽  
Endurance Performance ◽  
Metabolic Power ◽  
Master Athletes ◽  
World Record ◽  
Running Speed ◽  
Record Data ◽  
Per Se ◽  
Scientific Results ◽  
World Records

Human physical performance is notably reduced with ageing. Although the effects of ageing are often compounded by disuse, the study of master athletes provides an opportunity for investigating the effects of ageing per se . It is often held that sprinting is more affected than endurance performance. However, past analyses of master athletic world record data have yielded opposite observations. We argue here that our understanding of these data improves by considering how, biomechanically, metabolic power is related to athletic performance. In line with earlier studies, our analysis showed that running speed declines with age in a more pronounced way for endurance events than for sprinting events, confirming former studies. However, when assessing the metabolic power required to achieve the running world records, sprint and endurance events show a relatively uniform decline with age across the different events. This study has reconciled formerly conflicting scientific results and improves our understanding of the ageing process. However, it is unclear as to which are the governing mechanisms that cause the different systems in our body, responsible for sprinting and for endurance performance, to be affected by ageing in a remarkably uniform way.

Calibration Issues of Dual-Polarization Radar Measurements

2005 ◽  
Vol 22 (8) ◽  
pp. 1138-1155 ◽  
Author(s):  
Alexander V. Ryzhkov ◽  
Scott E. Giangrande ◽  
Valery M. Melnikov ◽  
Terry J. Schuur
Keyword(s):  
High Elevation ◽  
Absolute Calibration ◽  
Dual Polarization ◽  
Light Rain ◽  
Weather Radars ◽  
Mechanical Constraints ◽  
Wide Range ◽  
Temporal Averaging ◽  
The Impact ◽  
Self Consistency

Abstract Techniques for the absolute calibration of radar reflectivity Z and differential reflectivity ZDR measured with dual-polarization weather radars are examined herein. Calibration of Z is based on the idea of self-consistency among Z, ZDR, and the specific differential phase KDP in rain. Extensive spatial and temporal averaging is used to derive the average values of ZDR and KDP for each 1 dB step in Z. Such averaging substantially reduces the standard error of the KDP estimate so the technique can be used for a wide range of rain intensities, including light rain. In this paper, the performance of different consistency relations is analyzed and a new self-consistency methodology is suggested. The proposed scheme substantially reduces the impact of variability in the drop size distribution and raindrop shape on the quality of the Z calibration. The new calibration technique was tested on a large polarimetric dataset obtained during the Joint Polarization Experiment in Oklahoma and yielded an accuracy of Z calibration within 1 dB. Absolute calibration of ZDR is performed using solar measurements at orthogonal polarizations and polarimetric properties of natural targets like light rain and dry aggregated snow that are probed at high elevation angles. Because vertical sounding is prohibited for operational Weather Surveillance Radar-1988 Doppler (WSR-88D) radars because of mechanical constraints, the existing methodology for ZDR calibration is modified for nonzenith elevation angles. It is shown that the required 0.1–0.2-dB accuracy of the ZDR calibration is potentially achievable.

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.

scholarly journals Effects of hyperoxia on ventilation and pulmonary hemodynamics during immersed prone exercise at 4.7 ATA: possible implications for immersion pulmonary edema

2010 ◽  
Vol 109 (1) ◽  
pp. 68-78 ◽  
Author(s):  
Dionne F. Peacher ◽  
Shelly R. H. Pecorella ◽  
John J. Freiberger ◽  
Michael J. Natoli ◽  
Eric A. Schinazi ◽  
...  
Keyword(s):  
Pulmonary Edema ◽  
Minute Ventilation ◽  
Progressive Increase ◽  
Respiratory Muscle Fatigue ◽  
Lung Water ◽  
Pulmonary Hemodynamics ◽  
Pulmonary Capillaries ◽  
Arterial Ph ◽  
Wide Range ◽  
Pulmonary Vascular Hypertension

Immersion pulmonary edema (IPE) can occur in otherwise healthy swimmers and divers, likely because of stress failure of pulmonary capillaries secondary to increased pulmonary vascular pressures. Prior studies have revealed progressive increase in ventilation [minute ventilation (V̇e)] during prolonged immersed exercise. We hypothesized that this increase occurs because of development of metabolic acidosis with concomitant rise in mean pulmonary artery pressure (MPAP) and that hyperoxia attenuates this increase. Ten subjects were studied at rest and during 16 min of exercise submersed at 1 atm absolute (ATA) breathing air and at 4.7 ATA in normoxia and hyperoxia [inspired PO2(PiO2) 1.75 ATA]. V̇e increased from early (E, 6th minute) to late (L, 16th minute) exercise at 1 ATA (64.1 ± 8.6 to 71.7 ± 10.9 l/min BTPS; P < 0.001), with no change in arterial pH or Pco2. MPAP decreased from E to L at 1 ATA (26.7 ± 5.8 to 22.7 ± 5.2 mmHg; P = 0.003). V̇e and MPAP did not change from E to L at 4.7 ATA. Hyperoxia reduced V̇e (62.6 ± 10.5 to 53.1 ± 6.1 l/min BTPS; P < 0.0001) and MPAP (29.7 ± 7.4 to 25.1 ± 5.7 mmHg, P = 0.002). Variability in MPAP among subjects was wide (range 14.1–42.1 mmHg during surface and depth exercise). Alveolar-arterial Po2difference increased from E to L in normoxia, consistent with increased lung water. We conclude that increased V̇e at 1 ATA is not due to acidosis and is more consistent with respiratory muscle fatigue and that progressive pulmonary vascular hypertension does not occur during prolonged immersed exercise. Wide variation in MPAP among healthy subjects is consistent with variable individual susceptibility to IPE.

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