Evaluation of neurogenic and metabolic influences from a perfused leg on respiratory exchanges

1959 ◽  
Vol 196 (2) ◽  
pp. 467-469 ◽  
Author(s):  
Harold N. Bailen ◽  
Steven M. Horvath
Keyword(s):  
Ventilatory Response ◽  
Pulmonary Ventilation ◽  
Femoral Nerve ◽  
Carbon Dioxide Production ◽  
Minute Volume ◽  
The Body ◽  
Equal Weight ◽  
Neural Pathways ◽  
Femoral Vessels ◽  
Series Of Experiments

Paired mongrel dogs of near equal weight were used in two separate series of perfusion experiments. In the first series, the amputated leg of the ‘perfused’ dog remained connected to the rest of the body by the femur and the femoral nerve. The arterial and venous femoral vessels were anastomosed to the corresponding vessels in the ‘donor’ dog. Three milligrams per kilogram of 2–4-dinitrophenol was injected intravenously into the donor dog which was now perfusing the amputated extremity. The expired air was collected, analyzed and subjected to statistical analysis. It was found that the minute volume, oxygen consumption and carbon dioxide production exhibited an increase of approximately 100% above control values in the donor dogs. The perfused animals in this series also exhibited marked increases in the same parameters. It was discovered that dinitrophenol was reaching the perfused animal via the blood supply of the intact femur. Therefore, a second series of experiments was undertaken in which the femur was also amputated leaving the nerves as the sole connection to the body of the animal. The donor dogs again exhibited the expected elevation in ventilatory function, but the perfused animals demonstrated no changes. In both series, severing the nerves did not alter the ventilatory response. The data suggest that increased metabolism per se does not stimulate pulmonary ventilation via neural pathways.

Patterns of cardiovascular and ventilatory response to elevated metabolic states in the lizard Varanus exanthematicus

2000 ◽  
Vol 203 (16) ◽  
pp. 2437-2445 ◽  
Author(s):  
J.W. Hicks ◽  
T. Wang ◽  
A.F. Bennett
Keyword(s):  
Ventilatory Response ◽  
Pulmonary Ventilation ◽  
Carbon Dioxide Production ◽  
Cardiac Response ◽  
Postprandial Period ◽  
Cardiopulmonary Support ◽  
State Dependent ◽  
Metabolic States ◽  
Rate Of Oxygen Consumption ◽  
Cardiopulmonary System

The principal function of the cardiopulmonary system is the precise matching of O(2) and CO(2) transport to the metabolic requirements of different tissues. In some ecothermic vertebrates (amphibians and reptiles), vdot (O2) increases dramatically following feeding. Factorial increments in vdot (O2) range from 1.7 to 44 times above resting rates, and in some cases vdot (O2) approaches or even exceeds values measured during physical activity. There is virtually no information on the cardiopulmonary response during the postprandial period in these animals or how the pattern of cardiopulmonary support compares with that during activity. In our experiments, pulmonary ventilation (vdot e), heart rate (fh), systemic blood flow (qdot (sys)), rate of oxygen consumption (vdot (O2)) and rate of carbon dioxide production (vdot (CO2)) were measured at 35 degrees C in the lizard Varanus exanthematicus for 24 h prior to the ingestion of meals of various sizes and measured continuously for up to 72 h during the postprandial period. The results of this study were compared with previously published values for treadmill exercise in the same experimental animals. The change in fh and stroke volume (V(S)) for a given increment in vdot (O2) did not differ during exercise and digestion. In contrast, the ventilatory response was very dependent on the nature of the elevated metabolic state. During digestion, an increase in vdot (O2) resulted in a relative hypoventilation in comparison with resting values, whereas hyperventilation characterized the response during activity. During exercise, breathing frequency (f) increased 10- to 40-fold above resting values accompanied by large reductions in tidal volume (V(T)). In contrast, postprandial increases in vdot (O2) resulted in relatively minor changes in f and V(T) almost doubled. These results indicate that, in these lizards, the cardiac response to elevated vdot (O2) is stereotyped, the response being predictable irrespective of the source of the metabolic increment. In contrast, the ventilatory response is flexible and state-dependent, not only in pattern but also in its frequency and volume components.

Speaking and Breathing in High Respiratory Drive

2002 ◽  
Vol 45 (1) ◽  
pp. 89-99 ◽  
Author(s):  
E. Fiona Bailey ◽  
Jeannette D. Hoit
Keyword(s):  
Lung Volume ◽  
Healthy Subjects ◽  
Pulmonary Ventilation ◽  
Respiratory Control ◽  
Minute Volume ◽  
The Body ◽  
Respiratory Drive ◽  
Rib Cage ◽  
High Drive ◽  
Expiratory Flow

Pulmonary ventilation during speech breathing reflects the sum of the airflow changes used to speak and to meet the metabolic needs of the body. Studying interactions between speaking and breathing may provide insights into the mechanisms of shared respiratory control. The purposes of this study were to determine if healthy subjects exhibit task-specific breathing behaviors in high respiratory drive and to document subjects' perceptions during breathing and speaking under these conditions. Ten men were studied in air and high CO 2 . Magnetometers were used to estimate lung volume, rib cage and abdomen volumes, minute volume, breathing frequency, tidal volume, inspiratory and expiratory duration, and inspiratory and expiratory flow. Subjects' perceptions were assessed informally. Results indicated that the chest wall kinematic behaviors associated with breathing and speaking in high drive were similar in pattern but differed in the magnitudes of lung volume and rib cage volume events and in inspiratory and expiratory flow. Linguistic influences remained strong, but not as strong as under normal conditions. All subjects reported a heightened sense of breathing-related discomfort during speaking as opposed to breathing in high respiratory drive. We conclude that in healthy subjects breathing behavior associated with speaking in high respiratory drive is guided continuously by shared linguistic and metabolic influences. A parallel-processing model is proposed to explain the behaviors observed.

Ventilatory response to forward acceleration

1960 ◽  
Vol 15 (5) ◽  
pp. 907-910 ◽  
Author(s):  
Fred W. Zechman ◽  
Neil S. Cherniack ◽  
Alvin S. Hyde
Keyword(s):  
Tidal Volume ◽  
Ventilatory Response ◽  
Work Of Breathing ◽  
Minute Volume ◽  
Alveolar Ventilation ◽  
Respiratory Frequency ◽  
Series Of Experiments ◽  
Nitrogen Elimination ◽  
Second Period

Two series of experiments dealing with the effect of forward acceleration on respiration in man were performed. In both series of studies the trunk was inclined 12 degrees in the direction of acceleration and a rate of onset of 1 g/sec. was used. In the first series, the effect of 5, 8 and 12 g on respiratory frequency, tidal volume, minute volume and nitrogen elimination was determined. Frequency increased, reaching an average of 39.2 cpm and tidal volumes decreased to an average of 318 cc at 12 g. The volume of nitrogen eliminated during a 30-second period, breathing O2 at 12 g, was essentially unchanged, suggesting that alveolar ventilation did not decrease. In the second series, O2 consumptions were measured before, during and after accelerations of 5, 8, 10, and 12 g. O2 consumptions increased with acceleration and it is presumed that the extra work of breathing may be an important contributing factor. Submitted on March 2, 1960

Macroanatomical Structure of the Lumbosacral Plexus and its Branches in the Indigenous Duck

2018 ◽  
Vol 52 (1-4) ◽  
pp. 1-9 ◽  
Author(s):  
MT Hussan ◽  
MS Islam ◽  
J Alam
Keyword(s):  
Hind Limb ◽  
Femoral Nerve ◽  
Morphological Structure ◽  
Spinal Nerve ◽  
The Body ◽  
Lumbar Plexus ◽  
Lumbosacral Plexus ◽  
Sacral Plexus ◽  
Spinal Nerves ◽  
Femoral Cutaneous Nerve

The present study was carried out to determine the morphological structure and the branches of the lumbosacral plexus in the indigenous duck (Anas platyrhynchos domesticus). Six mature indigenous ducks were used in this study. After administering an anesthetic to the birds, the body cavities were opened. The nerves of the lumbosacral plexus were dissected separately and photographed. The lumbosacral plexus consisted of lumbar and sacral plexus innervated to the hind limb. The lumbar plexus was formed by the union of three roots of spinal nerves that included last two and first sacral spinal nerve. Among three roots, second (middle) root was the highest in diameter and the last root was least in diameter. We noticed five branches of the lumbar plexus which included obturator, cutaneous femoral, saphenus, cranial coxal, and the femoral nerve. The six roots of spinal nerves, which contributed to form three trunks, formed the sacral plexus of duck. The three trunks united medial to the acetabular foramen and formed a compact, cylindrical bundle, the ischiatic nerve. The principal branches of the sacral plexus were the tibial and fibular nerves that together made up the ischiatic nerve. Other branches were the caudal coxal nerve, the caudal femoral cutaneous nerve and the muscular branches. This study was the first work on the lumbosacral plexus of duck and its results may serve as a basis for further investigation on this subject.

On the Regulation of the Respiration in Reptiles

1961 ◽  
Vol 38 (2) ◽  
pp. 301-314 ◽  
Author(s):  
BODIL NIELSEN
Keyword(s):  
Steady State ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Temperature Interval ◽  
Normal Values ◽  
Pulmonary Ventilation ◽  
The Body ◽  
Respiratory Frequency ◽  
Temperature Changes ◽  
Instantaneous Increase

1. In two species of Lacerta (L. viridis and L. sicula) the effects on respiration of body temperature (changes in metabolic rate) and of CO2 added to the inspired air were studied. 2. Pulmonary ventilation increases when body temperature increases. The increase is brought about by an increase in respiratory frequency. No relationship is found between respiratory depth and temperature. 3. The rise in ventilation is provoked by the needs of metabolism and is not established for temperature regulating purposes (in the temperature interval 10°-35°C). 4. The ventilation per litre O2 consumed has a high numerical value (about 75, compared to about 20 in man). It varies with the body temperature and demonstrates that the inspired air is better utilized at the higher temperatures. 5. Pulmonary ventilation increases with increasing CO2 percentages in the inspired air between o and 3%. At further increases in the CO2 percentage (3-13.5%) it decreases again. 6. At each CO2 percentage the pulmonary ventilation reaches a steady state after some time (10-60 min.) and is then unchanged over prolonged periods (1 hr.). 7. The respiratory frequency in the steady state decreases with increasing CO2 percentages. The respiratory depth in the steady state increases with increasing CO2 percentages. This effect of CO2 breathing is not influenced by a change in body temperature from 20° to 30°C. 8. Respiration is periodically inhibited by CO2 percentages above 4%. This inhibition, causing a Cheyne-Stokes-like respiration, ceases after a certain time, proportional to the CO2 percentage (1 hr. at 8-13% CO2), and respiration becomes regular (steady state). Shift to room air breathing causes an instantaneous increase in frequency to well above the normal value followed by a gradual decrease to normal values. 9. The nature of the CO2 effect on respiratory frequency and respiratory depth is discussed, considering both chemoreceptor and humoral mechanisms.

scholarly journals VENTILATORY AND METABOLIC RESPONSES DURING FIELD TESTS AND CPX IN OBESE ADULTS

2017 ◽  
Vol 25 (1) ◽  
pp. 168
Author(s):  
Nicole Oliver ◽  
Renata Carlos ◽  
Tatiana Onofre ◽  
Joceline Cássia Ferezini De Sá ◽  
Eliane Pereira Da Silva ◽  
...  
Keyword(s):  
Field Tests ◽  
Carbon Dioxide Production ◽  
Cross Sectional Study ◽  
Peak Oxygen Uptake ◽  
Cardiopulmonary Exercise Test ◽  
Rehabilitation Program ◽  
The Body ◽  
University Hospital ◽  
Functional Evaluation ◽  
Cross Sectional

The 6 minute walk test (6MWT) and the incremental shuttle walking test (ISWT) have been used as an alternative to the Cardiopulmonary Exercise Test (CPX) for functional evaluation as well after rehabilitation programs. The objective was to analysis the cardiorespiratory and metabolic demands among the ISWT, 6MWT and CPX in the obese and the contribution of adiposity markers on this response. An observational and cross-sectional study was conducted with fifteen obese (10 women; 39.4+10.1years), performing CPX, 6MWT and ISWT. The subjects were as initial part of a rehabilitation program and bariatric surgery at the University Hospital. Metabolic and ventilatory variables were recorded by a telemetry system during all tests. Peak oxygen uptake-VO2peak was similar between CPX (18.6±4.0ml/kg/min) and ISWT (15.4±2.9ml/kg/min) and different from 6MWT (13.2±2.5ml/kg/min). There was agreement (3.2ml/kg/min; 95%; IC-3.0-9.4) between VO2peak of CPX and ISWT. CPX duration (R2=0.61;p=0.001) was best-fit by waist circumference (WC) and the body adiposity index(BAI) that reduced 4.7% and 3.2% CPX duration respectively. Forced vital capacity-FVC and WC predicts increasing of carbon dioxide production (VCO2) on CPX (R2=0.95;p=0.001) and ISWT (R2=0.67;p=0.001). In conclusion the obese individuals perform the ISWT and CPX test with similar physiological responses. It is suggested that, ISWT could be an alternative to CPX and that metabolic monitoring of ISWT by telemetry can be useful for the clinical assessment of the functional capacity of the obese.

Effect of temperature on central chemical control of ventilation in the alligator Alligator mississippiensis

1993 ◽  
Vol 179 (1) ◽  
pp. 261-272
Author(s):  
L. G. Branco ◽  
S. C. Wood
Keyword(s):  
Fourth Ventricle ◽  
Ventilatory Response ◽  
Pulmonary Ventilation ◽  
Gas Mixtures ◽  
Alligator Mississippiensis ◽  
Effect Of Temperature ◽  
Peripheral Chemoreceptor ◽  
Peripheral Chemoreceptors ◽  
Ph Values ◽  
Arterial Ph

Central chemoreceptor function was assessed in unanesthetized alligators, Alligator mississippiensis, at body temperatures of 15, 25 and 35 degrees C. Two experiments were performed. In the first experiment, the fourth ventricle was perfused with mock cerebrospinal fluid (CSF) solutions of different pH values (7.1-7.9). Changes in pulmonary ventilation were evaluated with a pneumotachograph and arterial pH (pHa) was measured. Perfusion with low-pH solutions increased ventilation and arterial pH. Perfusion with high-pH solutions decreased ventilation and arterial pH. Mock CSF pH had a greater effect at higher temperatures. In the second experiment, the relative contributions of central and peripheral chemoreceptor drive to breathing were evaluated using hypercapnic gas mixtures to stimulate both central and peripheral chemoreceptors. Hypercapnia caused an increase in ventilation which was larger at higher temperatures. To stimulate only the peripheral chemoreceptors, the same hypercapnic gas mixtures were applied while the CSF pH of the fourth ventricle was kept constant by perfusion with a mock CSF solution. This reduced significantly the ventilatory response induced by hypercapnia. These data indicate that, regardless of the temperature, central chemoreceptors play a major role in the ventilatory regulation of the alligator. The change in pHa with temperature is compatible with the alphastat hypothesis.

Regulations in the induction of the organized neural system in amphibian embryos

Development ◽  
1990 ◽  
Vol 110 (3) ◽  
pp. 653-659 ◽  
Author(s):  
T. Yamada
Keyword(s):  
Homeobox Gene ◽  
Internal Surface ◽  
Neural System ◽  
The Body ◽  
Convergent Extension ◽  
Kinase C ◽  
Amphibian Embryos ◽  
Series Of Experiments ◽  
System 1 ◽  
Posterior Anterior

Some of the recent data on the induction of the neural system in amphibian embryos are reviewed, utilizing a model, according to which two basic events regulate in this system: (1) ectodermal dorsalization, which occurs all over the induced region of the ectoderm and is responsible for the neural and mesectodermal pathways and (2) caudalization, which occurs only on the posterior level of dorsalized ectoderm and is responsible for the posterior mode of induced differentiation, functioning as a gradient with the apex at the posterior end of the embryo. Dorsalization of ectoderm can be caused by treatment with Con A or TPA, both of which are potential mitogens. Not only after the treatment with TPA, but also during normal dorsalization, the activation of protein kinase C occurs in responding cells. The possibility is suggested that an early step of mitogenic transmembrane signal transduction induced by a growth factor regulates dorsalization in intact embryos. Ectodermal dorsalization is responsible for the appearance of neuronal and glial cell lineages, and independent of the ECM network formed on the internal surface of the responding ectoderm during gastrulation. In caudalization, a series of experiments suggests that the regulatory role is played by the transcript of the mesodermal posterior homeobox gene, Xhox 3. The expression of this gene in time and location closely coincides with the pattern of convergent extension, one type of morphogenetic movement, which is expressed in a posterior-anterior gradient. This directed cell motility is responsible for the formation of the body axis of vertebrates, and was shown to be involved in caudalization by earlier induction experiments in urodele embryos.(ABSTRACT TRUNCATED AT 250 WORDS)

Hypoxic ventilatory response and arterial desaturation during heavy work

1989 ◽  
Vol 67 (3) ◽  
pp. 1119-1124 ◽  
Author(s):  
S. R. Hopkins ◽  
D. C. McKenzie
Keyword(s):  
Maximal Exercise ◽  
Ventilatory Response ◽  
Pulmonary Ventilation ◽  
Ideal Gas ◽  
Respiratory Drive ◽  
O2 Uptake ◽  
Arterial Blood ◽  
Arterial Desaturation ◽  
Exercise Ventilation ◽  
Arterial O2 Saturation

Arterial desaturation in athletes during intense exercise has been reported by several authors, yet the etiology of this phenomenon remains obscure. Inadequate pulmonary ventilation, due to a blunted respiratory drive, has been implicated as a factor. To investigate the relationship between the ventilatory response to hypoxia, exercise ventilation, and arterial desaturation, 12 healthy male subjects [age, 23.8 +/- 3.6 yr; height, 181.6 +/- 5.6 cm; weight, 73.7 +/- 6.2 kg; and maximal O2 uptake (VO2max), 63.0 +/- 2.2 ml.kg-1 min-1] performed a 5-min treadmill test at 100% of VO2max, during which arterial blood samples and ventilatory data were collected every 15 s. Alveolar PO2 (PAO2) was determined using the ideal gas equation. On a separate occasion the ventilatory response to isocapnic hypoxia was measured. Arterial PO2 decreased by an average of 29 Torr during the test, associated with arterial desaturation [arterial O2 saturation (SaO2) 92.0%]. PAO2 was maintained; however, alveolar-arterial gas pressure difference increased progressively to greater than 40 Torr. Minimal hypocapnia was observed, despite marked metabolic acidosis. There was no significant correlation observed between hypoxic drives and ventilation-to-O2 uptake ratio or SaO2 (r = 0.1 and 0.06, respectively, P = NS). These data support the conclusions that hypoxic drives are not related to maximal exercise ventilation or to the development of arterial desaturation during maximal exercise.

Prolonged “Phantom” Square Wave Capnograph Tracing after Patient Disconnection or Extubation

1997 ◽  
Vol 86 (3) ◽  
pp. 729-735 ◽  
Author(s):  
Yehuda Ginosar ◽  
Dimitry Baranov
Keyword(s):  
Reverse Flow ◽  
Minute Volume ◽  
Positive Pressure ◽  
Positive End Expiratory Pressure ◽  
Square Wave ◽  
Expired Gas ◽  
Experienced Anesthesiologist ◽  
Series Of Experiments ◽  
Evacuation System ◽  
Flap Valve

Background The authors report on the appearance of misleading square wave "phantom" capnograph tracings for approximately 3 min after disconnection from the Siemens Servo 900c ventilator. A series of experiments are described to examine the mechanism of this phenomenon. Methods Patients were ventilated using the Siemens Servo 900c ventilator with the following settings: minute volume, 5 1/min; respiratory rate, 8 breaths/min; PEEP, 0 cm H2O; trigger sensitivity, 20 cm H2O. The ventilator was connected to the Siemens Servo Evac 180 evacuation system (25 1/min on evacuation flowmeter). Airway pressure and capnography were recorded at the Y piece during ventilation and after disconnection. A back-up ventilator was used to support the patient during disconnection of the ventilator being studied. Results Initially, the "phantom" capnograph tracing closely resembled the square wave capnograph tracing before disconnection, but the amplitude and shape of the waveform gradually decayed. Based on experiments described in this article, the authors show that the carbon dioxide for the "phantom" capnograph tracing comes from the gas exhaled by the patient in the last breaths before disconnection and which is present in both the expiratory tubing and in the evacuation system. The small pressure gradient between the exhaust reservoir and the atmosphere causes reverse flow of expired gas after disconnection, when both the nonreturn flap valve at the exhaust outlet is open (due to minimal valve incompetence) and when the expiratory servo valve is open (in the absence of positive end-expiratory pressure). This continuous reverse flow is detected by the capnograph but is interrupted intermittently by each attempted positive pressure ventilation, thereby creating a "phantom" capnograph. Conclusions After accidental disconnection of the patient from the breathing system, or after accidental extubation of the trachea, the "phantom" capnograph is likely to confuse even an experienced anesthesiologist into the mistaken belief that his rapidly deteriorating patient is being ventilated adequately. Several potential mechanisms to eliminate this phenomenon are outlined, including the avoidance of zero positive end-expiratory pressure. "Phantom" capnography provides an illustration of the dangers of using monitoring techniques, however reliable, as a substitute for vigilant clinical observation.

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