Influence of prior ventilatory experience on the estimation of breathlessness during exercise

1990 ◽  
Vol 78 (2) ◽  
pp. 149-153 ◽  
Author(s):  
Rachel C. Wilson ◽  
P. W. Jones
Keyword(s):  
Exercise Test ◽  
Prior Experience ◽  
Minute Ventilation ◽  
Normal Subjects ◽  
Resistive Load ◽  
Inspiratory Time ◽  
Borg Scale ◽  
Exercise Tests ◽  
Loaded Breathing ◽  
Inspiratory Load

1. The intensity of breathlessness was measured during exercise in nine normal subjects using a modified Borg scale to examine the effect of prior experience of breathlessness on subsequent estimates of breathlessness. 2. Each subject performed four exercise tests, each of which consisted of two identical runs of workload incrementation (run 1 and run 2). An inspiratory resistive load of 3.8 cmH2O s−1 l−1 was applied during the appropriate run of the exercise test to examine the effect of (a) prior experience of ‘loaded’ breathing on breathlessness estimation during ‘unloaded’ breathing, and (b) prior experience of ‘unloaded’ breathing on breathlessness estimation during ‘loaded’ breathing. Run 1 was the conditioning run; run 2 was the run in which the effect of conditioning was measured. 3. There was a good correlation between breathlessness and minute ventilation during both unloaded’ breathing (median r = 0.93) and ‘loaded’ breathing (median r = 0.95). 4. The slope of the Borg score/minute ventilation relationship was greater during ‘loaded’ breathing than during ‘unloaded’ breathing (P < 0.01). There was no difference in mean Borg score between ‘unloaded’ and ‘loaded’ breathing. 5. After a period of ‘loaded’ breathing during run 1, estimated breathlessness was significantly reduced during ensuing ‘unloaded’ breathing in run 2 (P < 0.01) compared with the exercise test in which ‘unloaded’ breathing was experienced throughout both run 1 and run 2. 6. After a period of ‘unloaded’ breathing in run 1, estimated breathlessness was significantly increased during ensuing ‘loaded’ breathing in run 2 (P < 0.01) compared with the exercise test in which the inspiratory load had already been experienced in run 1. 7. Changes in the pattern of breathing (inspiratory time, expiratory time, total breath duration, inspiration time/total breath duration ratio and tidal volume) were not consistent with the changes in breathlessness. 8. We suggest that perception of breathlessness may be influenced by a subject's immediate prior experience of an altered relationship between breathlessness and ventilation.

A comparison of the visual analogue scale and modified Borg scale for the measurement of dyspnoea during exercise

1989 ◽  
Vol 76 (3) ◽  
pp. 277-282 ◽  
Author(s):  
Rachel C. Wilson ◽  
P. W. Jones
Keyword(s):  
Visual Analogue Scale ◽  
Analogue Scale ◽  
Minute Ventilation ◽  
Normal Subjects ◽  
Work Rate ◽  
Borg Scale ◽  
Exercise Tests ◽  
Vas Score ◽  
The Mean ◽  
The Relationship

1. The intensity of breathlessness during exercise was measured in ten normal subjects using a visual analogue scale (VAS) and a Borg scale to compare the use of the scales and their repeatability, both within the duration of a period of exercise and between tests. For each scale, subjects performed two exercise tests separated by a period of 2–6 weeks. Each exercise test consisted of two cycles of progressively increasing and decreasing workload. 2. All subjects felt confidently able to use both scales to quantify their feelings of breathlessness exclusively of other sensation. Equal preference was expressed for use of a particular scale. 3. With both scales there was a large intersubject variation in the relationship between dyspnoea score and minute ventilation (VE) (P < 0.01), and in the range of the scale used. 4. There was a good correlation between the VAS and Borg scores at each level of VE (r2 = 0.71), but the VAS score was used over a wider range than the Borg score. 5. The relationship between VE and the dyspnoea score measured by the two techniques was predominantly linear. The mean r2 for VAS score/VE was 0.68 (sd 0.19) and for Borg score/VE the mean r2 was 0.75 (sd 0.13). 6. The relationships VAS score/VE and Borg score/VE were unaffected by the direction in which the workload was varied (P > 0.05). 7. VE, measured at each work rate, did not differ between the two cycles (P > 0.05) or between the 2 days (P > 0.05). 8. With both scales, the slope of the VE-breathlessness relationship was slightly higher during the second half of the exercise compared with the first (0.05 < P > 0.01). 9. The scores with both scales were lower in the second test compared with the first (P < 0.01): Borg 16% lower, VAS 27% lower. 10. Measurements of dyspnoea made with the Borg scale appeared to have greater stability than VAS measurements and to correlate with VE a little better.

Long-term reproducibility of Borg scale estimates of breathlessness during exercise

1991 ◽  
Vol 80 (4) ◽  
pp. 309-312 ◽  
Author(s):  
Rachel C. Wilson ◽  
P. W. Jones
Keyword(s):  
Minute Ventilation ◽  
Normal Subjects ◽  
Work Rate ◽  
Borg Scale ◽  
Exercise Tests ◽  
Reliable Technique ◽  
Significant Difference ◽  
The Mean ◽  
The Relationship

1. The intensity of breathlessness in normal subjects during exercise was measured on seven occasions over a 40-week study period to assess the long-term repeatability of Borg scale estimates of breathlessness. 2. In all subjects there was a significant correlation (P = 0.0001) between breathlessness and minute ventilation. Minute ventilation measured at each work rate did not differ between the seven exercise tests (P >0.05). 3. There was no significant difference between the mean Borg scores (measured with respect to a given level of ventilation) in 5 of the 7 test weeks (P >0.05). The slope of the relationship Borg score/minute ventilation did not differ between the seven exercise tests (P >0.05). 4. Breathlessness estimation was highly reproducible both after 1 week and after 40 weeks of the study (both P >0.05). 5. The duration without testing between consecutive tests did not affect reproducibility: the mean Borg score was as equally reproducible after an interval of 22 weeks without testing as after an interval of 1 week (P >0.05). 6. The Borg scale provides a reliable technique for studying the sensation of breathlessness over extended time periods.

Experimental Pain Augments Experimental Dyspnea, but Not Vice Versa in Human Volunteers 

1999 ◽  
Vol 91 (6) ◽  
pp. 1633-1633 ◽  
Author(s):  
Takashi Nishino ◽  
Naohito Shimoyama ◽  
Tohru Ide ◽  
Shiroh Isono
Keyword(s):  
Cuff Pressure ◽  
Minute Ventilation ◽  
Experimental Pain ◽  
Respiratory Drive ◽  
Resistive Load ◽  
Pain Stimulus ◽  
Vas Score ◽  
Pain Stimulation ◽  
Loaded Breathing ◽  
Vas Scores

Background Pain and dyspnea frequently coexist in many clinical situations. However, whether the two different symptoms interact with each other has not been elucidated. To elucidate the interaction between pain and dyspneic sensations, the authors investigated separately the effects of pain on dyspnea and the effects of dyspnea on pain in 15 healthy subjects. Methods Subjects were asked to rate their sensation of pain or dyspnea using a visual analog scale (VAS) during pain stimulation produced by tourniquet inflation (inflation cuff pressure: 350 mmHg) around the calf, and/or the respiratory loading consisted of a combination of resistive load (77 cm H2O x l(-1) x s(-1)) and hypercapnia induced by extra mechanical dead space (255 ml). In addition to changes in VAS scores, changes in ventilatory airflow and airway pressure were continuously measured. Results Pain stimulation and loaded breathing increased VAS scores, ventilation, and occlusion pressure (P0.1). The addition of a pain stimulus during loaded breathing increased the dyspneic VAS score (median 56 [interquartile range 50-62] vs. 64 [55-77]: before vs. after addition of pain stimulus, P &lt; 0.05) with concomitant increases in minute ventilation (10.8 [10.1-13.3] vs. 12.4 [11.0-14.8] l/min, P &lt; 0.05) and P0.1 (5.5 [4.9-7.2] vs. 6.8 [5.8-9.0] cm H2O, P &lt; 0.05). The addition of respiratory loading during pain stimulation did not cause a significant change in pain VAS score (40 [33-55] vs. 31 [30-44]: before vs. after addition of respiratory loading), although both additional burdens increased further minute ventilation (10.0 [8.8-10.9] vs. 12.0 [10.6-13.2] l/min, P &lt; 0.05) and P0.1 (2.5 [2.0-3.0] vs. 6.2 [4.9-7.0] cm H2O, P &lt; 0.05). Conclusion The authors' findings suggest that pain intensifies the dyspneic sensation, presumably by increasing the respiratory drive, whereas dyspnea may not intensify the pain sensation.

Airway anesthesia effects on hypercapnic breathing pattern in humans

1983 ◽  
Vol 55 (2) ◽  
pp. 368-376 ◽  
Author(s):  
T. Y. Sullivan ◽  
P. L. Yu
Keyword(s):  
Airway Resistance ◽  
Vital Capacity ◽  
Breathing Pattern ◽  
Minute Ventilation ◽  
Normal Subjects ◽  
Inspiratory Time ◽  
Abrupt Increase ◽  
Thoracic Gas Volume ◽  
Before And After ◽  
Gas Volume

Minute ventilation (VE) and breathing pattern during an abrupt increase in fractional CO2 were compared in 10 normal subjects before and after airway anesthesia. Subjects breathed 7% CO2-93% O2 for 5 min before and after inhaling aerosolized lidocaine. As a result of airway anesthesia, VE and tidal volume (VT) were greater during hypercapnia, but there was no effect on inspiratory time (TI). Therefore, airway anesthesia produced an increase in mean inspiratory flow (VT/TI) during hypercapnia. The increase in VT/TI was compatible with an increase in neuromuscular output. There was no effect of airway anesthesia on the inspiratory timing ratio or the shape and position of the curve relating VT and TI. We also compared airway resistance (Raw), thoracic gas volume, forced vital capacity, forced expired volume at 1s, and maximum midexpiratory flow rate before and after airway anesthesia. A small (0.18 cmH2O X l-1 X s) decrease in Raw occurred after airway anesthesia that did not correlate with the effect of airway anesthesia on VT/TI. We conclude that airway receptors accessible to airway anesthesia play a role in hypercapnic VE.

Effect of residence at altitude on the perception of breathlessness on return to sea level in normal subjects

1993 ◽  
Vol 84 (2) ◽  
pp. 159-167 ◽  
Author(s):  
Rachel C. Wilson ◽  
W. L. G. Oldfield ◽  
P. W. Jones
Keyword(s):  
Oxygen Consumption ◽  
Tidal Volume ◽  
Sea Level ◽  
Minute Ventilation ◽  
Normal Subjects ◽  
Cycle Ergometer ◽  
Respiratory Frequency ◽  
Borg Scale ◽  
Oxygen Pulse ◽  
Ventilatory Equivalent

1. The effect of residence at altitude on the perception of breathlessness after return to sea level was examined in normal subjects. Breathlessness (Borg scale), minute ventilation, respiratory frequency, tidal volume, ‘oxygen pulse’ (oxygen consumption/heart rate) and the ventilatory equivalent for oxygen (minute ventilation/oxygen consumption) were measured at exercise (cycle-ergometer) during 5 months of training before 4 weeks at 4000 m and during the 6 month period after return to sea level. 2. There was no change in the subjects' pattern of breathing (respiratory frequency and tidal volume) or ‘oxygen pulse’ after the period at altitude (P = 0.0001). The ventilatory equivalent for oxygen was increased at all work rates after the period at altitude (P = 0.02). This ratio was slightly lower after 6 weeks and had returned to normal by 6 months (P = 0.4). 3. During training there was no change in breathlessness score (P = 0.6). On return to sea level, breathlessness score relative to ventilation was reduced (P = 0.0001). This was maintained for at least 6 weeks, but not as long as 6 months. 4. This study has demonstrated that, in normal subjects, the otherwise stable and reproducible relationship between breathlessness and ventilation may be disrupted for several weeks by factors other than lung disease. 5. The mechanism responsible for this is not clear, but the observations are consistent with the hypothesis that prior experience of breathlessness may condition subsequent estimates of breathlessness.

Effects of chest wall vibration on breathlessness during hypercapnic ventilatory response

1998 ◽  
Vol 84 (5) ◽  
pp. 1487-1491 ◽  
Author(s):  
Hidenori Edo ◽  
Hiroshi Kimura ◽  
Mafumi Niijima ◽  
Hideo Sakabe ◽  
Masato Shibuya ◽  
...  
Keyword(s):  
Chest Wall ◽  
Visual Analog Scale ◽  
Ventilatory Response ◽  
Minute Ventilation ◽  
Resistive Load ◽  
Vibratory Stimulation ◽  
Analog Scale ◽  
Hypercapnic Ventilatory Response ◽  
Mouth Occlusion Pressure ◽  
Inspiratory Load

Vibratory stimulation applied to the chest wall during inspiration reduces the intensity of breathlessness, whereas the same stimulation during expiration has no effect or may increase breathlessness. The purpose of the present study was to determine whether vibration reduced the intensity of breathlessness during progressive hypercapnia with and without the addition of an external resistive load. A second objective was to see whether the mouth occlusion pressure at 0.2 s (P0.2) was reduced by the vibratory stimulation. Hypercapnic ventilatory response was conducted in 10 healthy male volunteers with simultaneous measurement of visual analog scale, P0.2, and minute ventilation. Hypercapnic ventilatory response was performed and randomly combined with or without vibratory stimulation (100 Hz) as well as with or without inspiratory load. With inspiratory load, in-phase vibration did not cause any significant changes in the slopes of P0.2 and minute ventilation to CO2, whereas the slope of visual analog scale to CO2 significantly decreased from 0.47 ± 0.15 to 0.34 ± 0.11 (SE) cm/Torr ( P < 0.05). We conclude that in-phase vibration could decrease the slope of breathlessness elicited by inspiratory load combined with hypercapnia without changing motor output.

Diaphragm and lung afferents contribute to inspiratory load compensation in awake ponies

1994 ◽  
Vol 76 (3) ◽  
pp. 1330-1339 ◽  
Author(s):  
H. V. Forster ◽  
T. F. Lowry ◽  
L. G. Pan ◽  
B. K. Erickson ◽  
M. J. Korducki ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Treadmill Exercise ◽  
Minute Ventilation ◽  
Inspiratory Time ◽  
Arterial Pco2 ◽  
Load Compensation ◽  
Expiratory Time ◽  
Inspiratory Load

We determined the effect of pulmonary vagal (hilar nerve) denervation (HND) and diaphragm deafferentation (DD) on inspiratory load compensation. We studied awake intact (I; n = 10), DD (n = 5), HND (n = 4), and DD+HND (n = 7) ponies at rest and during mild (1.8 mph, 5% grade) and moderate (1.8 mph, 15% grade) treadmill exercise before, during, and after resistance of the inspiratory circuit was increased from approximately 1.5 to approximately 20 cmH2O.l–1.s. During the first loaded breath in I ponies at rest, inspiratory time (TI) increased, expiratory time decreased, and inspiratory drive increased. There were minimal changes after the first breath, and inspiratory minute ventilation (VI) and arterial PCO2 did not change (P > 0.10) from control values. On the first loaded breath during exercise, TI increased but inspiratory drive either did not change or decreased from control values. TI and drive increased after the first breath, but the increases were insufficient to maintain VI and arterial PCO2 at control levels. First-breath load compensation remained after DD, HND, and DD+HND, but after DD+HND tidal volume and VI were compensated 5–10% less (P < 0.05) than in I ponies. In all groups inspiratory drive, tidal volume, and VI were markedly augmented on the first breath after loading was terminated with a gradual return toward control. We conclude that diaphragm and pulmonary afferents contribute to but are not essential for inspiratory load compensation in awake ponies.

Sensation of inspired volume in normal subjects and quadriplegic patients

1982 ◽  
Vol 53 (6) ◽  
pp. 1481-1486 ◽  
Author(s):  
A. F. DiMarco ◽  
D. A. Wolfson ◽  
S. B. Gottfried ◽  
M. D. Altose
Keyword(s):  
Magnitude Estimation ◽  
Muscle Tension ◽  
Upper Airway ◽  
Normal Subjects ◽  
Motor Command ◽  
Resistive Load ◽  
Rib Cage ◽  
Lidocaine Solution ◽  
Loaded Breathing ◽  
The Central Nervous System

To investigate the influence of respiratory muscle tension and feedback from rib cage receptors, the sensation of inspired volume was compared in normal subjects and quadriplegic patients during active breathing, with and without the addition of an inspiratory resistive load, and during passive ventilation produced by a tank respirator. In separate trials, volume sensation was assessed using tests of magnitude estimation and volume reproduction. The mean exponents and standard errors for the magnitude estimation of inspired volume in normal subjects were 1.32 +/- 0.08, 1.24 +/- 0.06, and 1.23 +/- 0.09 during passive, active, and loaded breathing, respectively. These values were not significantly different from one another, nor were there any differences between normal subjects and quadriplegics. During volume reproduction trials where the mechanical conditions were different between control and test breaths, the inspired volumes during active unloaded breathing were significantly smaller than during passive ventilation but greater than the inspired volumes during loaded breathing. Errors in volume reproduction were no different in normal subjects and quadriplegics, suggesting that inputs from rib cage receptors are not essential for the sensation of inspired volume. The sensation of inspired volume in both normal subjects and quadriplegics was found to be unaffected by inhalation of a 2% lidocaine solution. This suggests that upper airway receptors are also not essential for volume sensation. The intensity of the sensation of a given inspired volume may depend on the level of the central nervous system motor command and/or on the tension developed by the diaphragm.

Effect of resistive loads on pattern of respiratory muscle recruitment during exercise

1991 ◽  
Vol 71 (5) ◽  
pp. 1941-1948 ◽  
Author(s):  
M. Ramonatxo ◽  
J. Mercier ◽  
R. Cohendy ◽  
C. Prefaut
Keyword(s):  
Respiratory Muscle ◽  
Minute Ventilation ◽  
Abdominal Muscles ◽  
Resistive Load ◽  
Muscle Recruitment ◽  
O2 Uptake ◽  
Exercise Tests ◽  
Co2 Output ◽  
Resistive Loads ◽  
Mouth Occlusion Pressure

In healthy subjects, we compared the effects of an expiratory (ERL) and an inspiratory (IRL) resistive load (6 cmH2O.l-1.s) with no added resistive load on the pattern of respiratory muscle recruitment during exercise. Fifteen male subjects performed three exercise tests at 40% of maximum O2 uptake: 1) with no-added-resistive load (control), 2) with ERL, and 3) with IRL. In all subjects, we measured breathing pattern and mouth occlusion pressure (P0.1) from the 3rd min of exercise, in 10 subjects O2 uptake (VO2), CO2 output (VCO2), and respiratory exchange ratio (R), and in 5 subjects we measured gastric (Pga), pleural (Ppl), and transdiaphragmatic (Pdi) pressures. Both ERL and IRL induced a high increase of P0.1 and a decrease of minute ventilation. ERL induced a prolongation of expiratory time with a reduction of inspiratory time (TI), mean expiratory flow, and ratio of inspiratory to total time of the respiratory cycle (TI/TT). IRL induced a prolongation of TI with a decrease of mean inspiratory flow and an increase of tidal volume and TI/TT. With ERL, in two subjects, Pga increased and Ppl decreased more during inspiration than during control suggesting that the diaphragm was the most active muscle. In one subject, the increases of Ppl and Pga were weak; thus Pdi increased very little. In the two other subjects, Ppl decreased more during inspiration but Pga also decreased, leading to a decrease of Pdi. This suggests a recruitment of abdominal muscles during expiration and of accessory and intercostal muscles during inspiration. With IRL, in all subjects, Ppl again decreased more, Pga began to decrease until 40% of TI and then increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Steady-state response of normal subjects to inspiratory resistive load

1986 ◽  
Vol 60 (5) ◽  
pp. 1471-1481 ◽  
Author(s):  
V. Im Hof ◽  
P. West ◽  
M. Younes
Keyword(s):  
Steady State ◽  
Normal Subjects ◽  
Driving Pressure ◽  
Resistive Load ◽  
Steady State Response ◽  
Occlusion Pressure ◽  
State Response ◽  
Inspiratory Resistance ◽  
Residual Capacity ◽  
Loaded Breathing

Tidal volume (VT) is usually preserved when conscious humans are made to breathe against an inspiratory resistance. To identify the neural changes responsible for VT compensation we calculated the respiratory driving pressure waveform during steady-state unloaded and loaded breathing (delta R = 8.5 cmH2O X 1(-1) X s) in eight conscious normal subjects. Driving pressure (DP) was calculated according to the method of Younes et al. (J. Appl. Physiol. 51: 963–989, 1981), which provides the equivalent of occlusion pressure at functional residual capacity throughout the breath. VT during resistance breathing was 108% of unloaded VT, as opposed to a predicted value of 82% of control in the absence of neural compensation. Compensation was accomplished through three changes in the DP waveform: 1) peak amplitude increased (+/- 23%), 2) the duration of the rising phase increased (+42%); and 3) the rising phase became more concave to the time axis. There were no changes in the relative decay rate of inspiratory pressure during expiration, in the shape of the declining phase of DP, or in end-expiratory lung volume.

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