Ventilatory Responses to Exercise and to Carbon Dioxide in Mitral Stenosis before and after Valvulotomy: Causes of Tachypnoea

1978 ◽  
Vol 54 (1) ◽  
pp. 9-16 ◽  
Author(s):  
J. W. Reed ◽  
M. Ablett ◽  
J. E. Cotes
Keyword(s):  
Carbon Dioxide ◽  
Tidal Volume ◽  
Mitral Stenosis ◽  
Vital Capacity ◽  
Minute Ventilation ◽  
Residual Effect ◽  
Minute Volume ◽  
Cardiac Frequency ◽  
Control Subjects ◽  
Exercise Ventilation

1. The ventilation and cardiac frequency during progressive exercise and the respiratory responses to breathing carbon dioxide have been measured in 33 female patients with mitral stenosis and in 31 control subjects. Compared with the control subjects, the patients' exercise ventilation and cardiac frequency were increased; the exercise tidal volume at standard minute volume, the vital capacity and the ventilatory response to carbon dioxide were reduced. The extent to which the standardized tidal volume was lower during exercise than during breathing carbon dioxide was correlated with the severity of the stenosis, as gauged by the increase in exercise cardiac frequency above the level predicted from anthropometric measurements. 2. Twenty patients were studied postoperatively. In the 12 who showed clinical improvement the exercise ventilation and cardiac frequency were reduced and the exercise tidal volume at a given minute ventilation was increased. The latter change occurred despite a reduction in vital capacity, which was probably a residual effect of thoractomy. There was no significant change in the response to breathing carbon dioxide. No material change in function was observed in the patients whose condition was not improved by the operation. 3. It is suggested that in mitral stenosis the tachypnoea which occurs during exercise, whilst mainly a mechanical consequence of the reduced vital, capacity, is also partly due to pulmonary congestion stimulating intrapulmonary receptors.

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.

Respiratory and abdominal muscle responses to expiratory threshold loading in cystic fibrosis

1992 ◽  
Vol 72 (3) ◽  
pp. 842-850 ◽  
Author(s):  
F. Cerny ◽  
L. Armitage ◽  
J. A. Hirsch ◽  
B. Bishop
Keyword(s):  
Cystic Fibrosis ◽  
Tidal Volume ◽  
Body Position ◽  
Minute Ventilation ◽  
Abdominal Muscle ◽  
Abdominal Muscles ◽  
Breathing Frequency ◽  
Control Subjects ◽  
Lung Dysfunction ◽  
Muscle Responses

We hypothesized that the hyperinflation and pulmonary dysfunction of cystic fibrosis (CF) would distort feedback and therefore alter the abdominal muscle response to graded expiratory threshold loads (ETLs). We compared the respiratory and abdominal muscle responses with graded ETLs of seven CF patients with severe lung dysfunction with those of matched healthy control subjects in the supine and 60 degrees head-up positions. Breathing frequency, tidal volume, and ventilatory timing were determined from inspiratory flow recordings. Abdominal electromyograms (EMGs) were detected with surface electrodes placed unilaterally over the external and internal oblique and the rectus abdominis muscles. Thresholds, times of onset, and durations of phasic abdominal activity were determined from raw EMGs; peak amplitudes were determined from integrated EMGs. Graded ETLs were imposed by submerging a tube from the expiratory port of the breathing valve into a column of water at depths of 0–25 cmH2O. We found that breathing frequency, tidal volume, and expired minute ventilation were higher in CF patients than in control subjects during low ETLs; a change in body position did not alter these ventilatory responses in the CF patients but did in the control subjects. All CF patients, but none of the control subjects, had tonic abdominal activity while supine. CF patients recruited abdominal muscles at lower loads, earlier in the respiratory cycle, and to a higher recruitment level in both positions than the control subjects, but burst duration of phasic activity was not different between groups.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Increased vasoconstriction predisposes to hyperpnea and postural faint

2008 ◽  
Vol 295 (1) ◽  
pp. H372-H381 ◽  
Author(s):  
Indu Taneja ◽  
Marvin S. Medow ◽  
June L. Glover ◽  
Neeraj K. Raghunath ◽  
Julian M. Stewart
Keyword(s):  
Tidal Volume ◽  
Minute Ventilation ◽  
Peripheral Resistance ◽  
Impedance Plethysmography ◽  
Blood Flows ◽  
Control Subjects ◽  
Regional Blood Flows ◽  
Healthy Control ◽  
End Tidal ◽  
Upright Tilt

Our prior studies indicated that postural fainting relates to splanchnic hypervolemia and thoracic hypovolemia during orthostasis. We hypothesized that thoracic hypovolemia causes excessive sympathetic activation, increased respiratory tidal volume, and fainting involving the pulmonary stretch reflex. We studied 18 patients 13–21 yr old, 11 who fainted within 10 min of upright tilt (fainters) and 7 healthy control subjects. We measured continuous blood pressure and heart rate, respiration by inductance plethysmography, end-tidal carbon dioxide (ETCO2) by capnography, and regional blood flows and blood volumes using impedance plethysmography, and we calculated arterial resistance with patients supine and during 70° upright tilt. Splanchnic resistance decreased until faint in fainters (44 ± 8 to 21 ± 2 mmHg·l−1·min−1) but increased in control subjects (47 ± 5 to 53 ± 4 mmHg·l−1·min−1). Percent change in splanchnic blood volume increased (7.5 ± 1.0 vs. 3.0 ± 11.5%, P < 0.05) after the onset of tilt. Upright tilt initially significantly increased thoracic, pelvic, and leg resistance in fainters, which subsequently decreased until faint. In fainters but not control subjects, normalized tidal volume (1 ± 0.1 to 2.6 ± 0.2, P < 0.05) and normalized minute ventilation increased throughout tilt (1 ± 0.2 to 2.1 ± 0.5, P < 0.05), whereas respiratory rate decreased (19 ± 1 to 15 ± 1 breaths/min, P < 0.05). Maximum tidal volume occurred just before fainting. The increase in minute ventilation was inversely proportionate to the decrease in ETCO2. Our data suggest that excessive splanchnic pooling and thoracic hypovolemia result in increased peripheral resistance and hyperpnea in simple postural faint. Hyperpnea and pulmonary stretch may contribute to the sympathoinhibition that occurs at the time of faint.

Iron-Deficiency Anaemia: Its Effect on Transfer Factor for the Lung (Diffusing Capacity) and Ventilation and Cardiac Frequency during Sub-Maximal Exercise

1972 ◽  
Vol 42 (3) ◽  
pp. 325-335 ◽  
Author(s):  
J. E. Cotes ◽  
J. M. Dabbs ◽  
P. C. Elwood ◽  
A. M. Hall ◽  
A. McDonald ◽  
...  
Keyword(s):  
Iron Deficiency ◽  
Transfer Factor ◽  
Iron Deficiency Anaemia ◽  
Maximal Exercise ◽  
Haemoglobin Concentration ◽  
Placebo Treatment ◽  
Deficiency Anaemia ◽  
Cardiac Frequency ◽  
Control Subjects ◽  
Exercise Ventilation

1. Measurements of transfer factor and sub-maximal exercise ventilation and cardiac frequency have been made on twenty women with iron-deficiency anaemia (Hb 8–9 g/100 ml) before and after ‘treatment’ with iron or placebo tablets and on control subjects. 2. The exercise ventilation, cardiac frequency and oxygen uptake were independent of haemoglobin concentration but the transfer factor was lower in the test than in control subjects and was increased by iron but not by placebo treatment. The results support the validity of the reaction-rate data for carbon monoxide with oxyhaemoglobin of Roughton & Forster (1957) despite evidence to the contrary from other studies. 3. In interpretation of sub-maximal exercise ventilation and cardiac frequency in iron-deficiency anaemia no allowance need be made for variation in haemoglobin concentration in the range 8–15 g/100 ml. For transfer factor a correction should be made by using a variant of the relationship of Roughton & Forster (1957).

scholarly journals Nasal high flow reduces minute ventilation during sleep through a decrease of carbon dioxide rebreathing

2019 ◽  
Vol 126 (4) ◽  
pp. 863-869 ◽  
Author(s):  
Maximilian Pinkham ◽  
Russel Burgess ◽  
Toby Mündel ◽  
Stanislav Tatkov
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Tidal Volume ◽  
Respiratory Rate ◽  
Dead Space ◽  
Minute Ventilation ◽  
Control Ventilation ◽  
High Flow ◽  
Carbon Dioxide Rebreathing ◽  
Anatomical Dead Space

Nasal high flow (NHF) is an emerging therapy for respiratory support, but knowledge of the mechanisms and applications is limited. It was previously observed that NHF reduces the tidal volume but does not affect the respiratory rate during sleep. The authors hypothesized that the decrease in tidal volume during NHF is due to a reduction in carbon dioxide (CO2) rebreathing from dead space. In nine healthy males, ventilation was measured during sleep using calibrated respiratory inductance plethysmography (RIP). Carbogen gas mixture was entrained into 30 l/min of NHF to obtain three levels of inspired CO2: 0.04% (room air), 1%, and 3%. NHF with room air reduced tidal volume by 81 ml, SD 25 ( P < 0.0001) from a baseline of 415 ml, SD 114, but did not change respiratory rate; tissue CO2 and O2 remained stable, indicating that gas exchange had been maintained. CO2 entrainment increased tidal volume close to baseline with 1% CO2 and greater than baseline with 3% CO2 by 155 ml, SD 79 ( P = 0.0004), without affecting the respiratory rate. It was calculated that 30 l/min of NHF reduced the rebreathing of CO2 from anatomical dead space by 45%, which is equivalent to the 20% reduction in tidal volume that was observed. The study proves that the reduction in tidal volume in response to NHF during sleep is due to the reduced rebreathing of CO2. Entrainment of CO2 into the NHF can be used to control ventilation during sleep. NEW & NOTEWORTHY The findings in healthy volunteers during sleep show that nasal high flow (NHF) with a rate of 30 l/min reduces the rebreathing of CO2 from anatomical dead space by 45%, resulting in a reduced minute ventilation, while gas exchange is maintained. Entrainment of CO2 into the NHF can be used to control ventilation during sleep.

scholarly journals Mechanisms of exercise limitation in patients with chronic hypersensitivity pneumonitis

2018 ◽  
Vol 4 (3) ◽  
pp. 00043-2018 ◽  
Author(s):  
Olívia Meira Dias ◽  
Bruno Guedes Baldi ◽  
Jeferson George Ferreira ◽  
Letícia Zumpano Cardenas ◽  
Francesca Pennati ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Hypersensitivity Pneumonitis ◽  
Vital Capacity ◽  
Minute Ventilation ◽  
Carbon Dioxide Production ◽  
Dynamic Hyperinflation ◽  
Oxygen Production ◽  
Lung Volumes ◽  
Exercise Limitation ◽  
Chronic Hypersensitivity Pneumonitis

Small airway and interstitial pulmonary involvements are prominent in chronic hypersensitivity pneumonitis (cHP). However, their roles on exercise limitation and the relationship with functional lung tests have not been studied in detail.Our aim was to evaluate exercise performance and its determinants in cHP. We evaluated maximal cardiopulmonary exercise testing performance in 28 cHP patients (forced vital capacity 57±17% pred) and 18 healthy controls during cycling.Patients had reduced exercise performance with lower peak oxygen production (16.6 (12.3–19.98) mL·kg−1·min−1versus 25.1 (16.9–32.0), p=0.003), diminished breathing reserve (% maximal voluntary ventilation) (12 (6.4–34.8)% versus 41 (32.7–50.8)%, p<0.001) and hyperventilation (minute ventilation/carbon dioxide production slope 37±5 versus 31±4, p<0.001). All patients presented oxygen desaturation and augmented Borg dyspnoea scores (8 (5–10) versus 4 (1–7), p=0.004). The prevalence of dynamic hyperinflation was found in only 18% of patients. When comparing cHP patients with normal and low peak oxygen production (<84% pred, lower limit of normal), the latter exhibited a higher minute ventilation/carbon dioxide production slope (39±5.0 versus 34±3.6, p=0.004), lower tidal volume (0.84 (0.78–0.90) L versus 1.15 (0.97–1.67) L, p=0.002), and poorer physical functioning score on the Short form-36 health survey. Receiver operating characteristic curve analysis showed that reduced lung volumes (forced vital capacity %, total lung capacity % and diffusing capacity of the lung for carbon dioxide %) were high predictors of poor exercise capacity.Reduced exercise capacity was prevalent in patients because of ventilatory limitation and not due to dynamic hyperinflation. Reduced lung volumes were reliable predictors of lower performance during exercise.

Similarities and differences in the exercise performance of patients after a modified Fontan procedure compared to patients with complete transposition following a Senning operation

2000 ◽  
Vol 10 (3) ◽  
pp. 201-207 ◽  
Author(s):  
Gernot Buheitel ◽  
Michael Hofbeck ◽  
Stephan Gerling ◽  
Andreas Koch ◽  
Helmut Singer
Keyword(s):  
Carbon Dioxide ◽  
Minute Ventilation ◽  
Fontan Procedure ◽  
Fontan Operation ◽  
Work Rate ◽  
Control Group ◽  
Control Subjects ◽  
Complete Transposition ◽  
Cavopulmonary Anastomosis ◽  
Senning Operation

AbstractObjectiveTo investigate cardiopulmonary performance in patients after a Fontan procedure, comparing it to patients following a Senning operation.MethodsWe studied 21 children, with a mean age of 11.1 years, after a total cavopulmonary anastomosis, comparing them to 13 with complete transposition after a Senning procedure, having a mean age of 11.8 years, and 21 control subjects with a mean age of 11.2 years. All were tested on a bicycle ergospirometer.ResultsPeak consumption of oxygen, maximal work rate, peak oxygen pulse and endexpiratory pressure of carbon dioxide at a work rate of 1.5 Watt/kg were lowest in patients with a modified Fontan procedure, and highest in the control group (p≤ 0.0278). Production of carbon dioxide, and minute ventilation at a work rate of 1.5 Watt/kg, was highest in the patients after Fontan procedure, and lowest in the healthy subjects (p≤ 0.0163). Production of carbon dioxide per single breath was lower in those having a Fontan procedure (28.9 ml) than in the two other groups (35.1 ml; p = 0.0243). The tidal volume showed no significant differences between the three groups.ConclusionsThe reaction to exercise was identical qualitatively in both groups of patients, and comparable to the behaviour of patients with chronic heart failure. Quantitatively, the results of the patients following a Senning procedure lay between those of control subjects and those who had undergone a Fontan operation. The only exception was dead space ventilation, where the patients after a Fontan procedure differed from the two other groups because of their increased ventilation-perfusion mismatch.

Absent peripheral chemosensitivity in Prader-Willi syndrome

1994 ◽  
Vol 77 (5) ◽  
pp. 2231-2236 ◽  
Author(s):  
D. Gozal ◽  
R. Arens ◽  
K. J. Omlin ◽  
S. L. Ward ◽  
T. G. Keens
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Vital Capacity ◽  
Minute Ventilation ◽  
Prader Willi Syndrome ◽  
Peripheral Chemoreceptor ◽  
Afferent Pathways ◽  
Ventilatory Responses ◽  
Control Subjects ◽  
And Control

Abnormalities in ventilatory control during wakefulness and sleep have been observed in patients with Prader-Willi syndrome (PWS). The role of peripheral chemoreceptors in the pathophysiology of abnormal ventilatory responses in PWS is unknown. We studied peripheral chemoreceptor function during wakefulness in 17 genetically confirmed PWS patients [age 27.0 +/- 2.5 (SE) yr; 7 males, 10 females; body mass index 31.1 +/- 1.4 kg/m2] and compared their responses with 17 control subjects matched for age, sex, and body mass index. All PWS and control subjects had normal resting end-tidal PCO2 and arterial O2 saturation while awake. Peripheral chemoreceptor function was assessed by the ventilatory responses to 100% O2 breathing, five tidal breaths of 100% N2, and vital capacity breaths of 15% CO2 in O2. Control subjects decreased minute ventilation (VE) by 15.5 +/- 3.6% during hyperoxia. However, PWS patients increased VE by 17.6 +/- 3.3%, indicating a paradoxical response to hyperoxia (P < 0.00001). After CO2 vital capacity breaths, PWS patients showed no significant change and control subjects showed a marked increase (P < 0.0001) in VE. During N2 breathing, again PWS patients showed no change and control subjects exhibited a marked increase (P < 0.00005) in VE. We conclude that PWS patients have absent peripheral chemoreceptor ventilatory responses. We speculate that the lack of ventilatory responses is due to primary peripheral chemoreceptor dysfunction and/or defective afferent pathways to central controllers.

scholarly journals Postoperative study of vital capacity and ventilation measurements following elective craniotomy

2008 ◽  
Vol 126 (1) ◽  
pp. 11-16 ◽  
Author(s):  
Luciana Carrupt Machado Sogame ◽  
Sonia Maria Faresin ◽  
Milena Carlos Vidotto ◽  
José Roberto Jardim
Keyword(s):  
Tidal Volume ◽  
Vital Capacity ◽  
Tumor Resection ◽  
Minute Volume ◽  
Respiratory Frequency ◽  
University Hospital ◽  
The Third ◽  
Aneurysm Clipping ◽  
Postoperative Study ◽  
Surgery Duration

CONTEXT AND OBJECTIVE: Changes in pulmonary function commonly occur after general surgery. The aims were to evaluate vital capacity, tidal volume and respiratory frequency among patients undergoing elective craniotomy and to determine possible correlations of these parameters with surgery duration and etiology for neurosurgery. DESIGN AND SETTING: Prospective, open study at a tertiary university hospital. METHODS: Twenty-six patients underwent elective craniotomy for aneurysm clipping (11) or tumor resection (15). Vital capacity (VC), tidal volume (TV), minute volume (VE) and respiratory rate were determined before the operation and on the first to fourth postoperative days. RESULTS: There were significant decreases of 25% in VC, 22% in TV and 12% in VE (p < 0.05) and no significant increase in respiratory frequency (5%) on the first postoperative day. VE returned to baseline on the second postoperative day and TV on the third postoperative day, while VC was 8% lower on the fourth postoperative day, compared with before the operation (p < 0.05). VC reduction was significantly greater in patients undergoing aneurysm clipping (43%) than in patients undergoing tumor resection (14%) when surgery duration was more than four hours (p < 0.05), with no significant change when surgery duration was less than four hours. CONCLUSION: Reductions in VC, TV and VE were observed during the postoperative period in patients undergoing aneurysm clipping or tumor resection. The reductions in VC and TV were greater in patients undergoing craniotomy due to aneurysm and with longer surgery duration.

Noninvasive Cardiac Output Measurement Using Partial Carbon Dioxide Rebreathing Is Less Accurate at Settings of Reduced Minute Ventilation and when Spontaneous Breathing Is Present

2003 ◽  
Vol 98 (4) ◽  
pp. 830-837 ◽  
Author(s):  
Kazuya Tachibana ◽  
Hideaki Imanaka ◽  
Muneyuki Takeuchi ◽  
Yuji Takauchi ◽  
Hiroshi Miyano ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Cardiac Output ◽  
Tidal Volume ◽  
Pressure Support Ventilation ◽  
Spontaneous Breathing ◽  
Pressure Support ◽  
Minute Ventilation ◽  
Support Ventilation ◽  
Carbon Dioxide Rebreathing ◽  
Controlled Mechanical Ventilation

Background Although evaluation of cardiac output by the partial carbon dioxide rebreathing technique is as accurate as thermodilution techniques under controlled mechanical ventilation, it is less accurate at low tidal volume. It is not clear whether reduced accuracy is due to low tidal volume or low minute ventilation. The effect of spontaneous breathing on the accuracy of partial carbon dioxide rebreathing measurement has not been fully investigated. The objectives of the current study were to investigate whether tidal volume or minute ventilation is the dominant factor for the accuracy, and the accuracy of the technique when spontaneous breathing effort is present. Methods The authors enrolled 25 post-cardiac surgery patients in two serial protocols. First, the authors applied three settings of controlled mechanical ventilation in random order: large tidal volume (12 ml/kg), the same minute ventilation with a small tidal volume (6 ml/kg), and 50% decreased minute ventilation with a small tidal volume (6 ml/kg). Second, when the patient recovered spontaneous breathing, the authors applied three conditions of partial ventilatory support in random order: synchronized intermittent mandatory ventilation-pressure support ventilation, pressure support ventilation with an appropriately adjusted rebreathing loop, and pressure support ventilation with the shortest available loop. After establishing steady state conditions, the authors measured cardiac output using both partial carbon dioxide rebreathing and thermodilution methods. The correlation between the data yielded by the two methods was determined by Bland-Altman analysis and linear regression. Results Cardiac output with the carbon dioxide rebreathing technique correlated moderately with that measured by thermodilution when minute ventilation was set to maintain normocapnia, regardless of tidal volumes. However, when minute ventilation was set low, the carbon dioxide rebreathing technique underreported cardiac output (y = 0.70x; correlation coefficient, 0.34; bias, -1.73 l/min; precision, 1.27 l/min; limits of agreement, -4.27 to +0.81 l/min). When there was spontaneous breathing, the correlation between the two cardiac output measurements became worse. Carbon dioxide rebreathing increased spontaneous tidal volume and respiratory rate (20% and 30%, respectively, during pressure support ventilation) when the rebreathing loop was adjusted for large tidal volume. Conclusions During controlled mechanical ventilation, minute ventilation rather than tidal volume affected the accuracy of cardiac output measurement using the partial carbon dioxide rebreathing technique. When spontaneous breathing is present, the carbon dioxide rebreathing technique is less accurate and increases spontaneous tidal volume and respiratory rate.

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