scholarly journals An optimized method for estimating the tidal volume from intracardiac or body surface electrocardiographic signals: implications for estimating minute ventilation

2014 ◽  
Vol 307 (3) ◽  
pp. H426-H436 ◽  
Author(s):  
Omid Sayadi ◽  
Eric H. Weiss ◽  
Faisal M. Merchant ◽  
Dheeraj Puppala ◽  
Antonis A. Armoundas
Keyword(s):  
Tidal Volume ◽  
Body Surface ◽  
Minute Ventilation ◽  
Absolute Error ◽  
Accurate Estimation ◽  
Clinical Settings ◽  
Mechanically Ventilated ◽  
Ecg Signals ◽  
Respiratory Signal ◽  
Respiratory Modulation

The ability to accurately monitor tidal volume (TV) from electrocardiographic (ECG) signals holds significant promise for improving diagnosis treatment across a variety of clinical settings. The objective of this study was to develop a novel method for estimating the TV from ECG signals. In 10 mechanically ventilated swine, we collected intracardiac electrograms from catheters in the coronary sinus (CS), left ventricle (LV), and right ventricle (RV), as well as body surface electrograms, while TV was varied between 0 and 750 ml at respiratory rates of 7–14 breaths/min. We devised an algorithm to determine the optimized respirophasic modulation of the amplitude of the ECG-derived respiratory signal. Instantaneous measurement of respiratory modulation showed an absolute error of 72.55, 147.46, 85.68, 116.62, and 50.89 ml for body surface, CS, LV, RV, and RV-CS leads, respectively. Minute TV estimation demonstrated a more accurate estimation with an absolute error of 69.56, 153.39, 79.33, 122.16, and 48.41 ml for body surface, CS, LV, RV, and RV-CS leads, respectively. The RV-CS and body surface leads provided the most accurate estimations that were within 7 and 10% of the true TV, respectively. Finally, the absolute error of the bipolar RV-CS lead was significantly lower than any other lead configuration ( P < 0.0001). In conclusion, we have demonstrated that ECG-derived respiratory modulation provides an accurate estimation of the TV using intracardiac or body surface signals, without the need for additional hardware.

Tachykinins mediate bronchoconstriction elicited by isocapnic hyperpnea in guinea pigs

1989 ◽  
Vol 66 (3) ◽  
pp. 1108-1112 ◽  
Author(s):  
D. W. Ray ◽  
C. Hernandez ◽  
A. R. Leff ◽  
J. M. Drazen ◽  
J. Solway
Keyword(s):  
Tidal Volume ◽  
Guinea Pigs ◽  
Minute Ventilation ◽  
Response Curves ◽  
Mechanically Ventilated ◽  
Stimulus Response ◽  
Respiratory System Resistance ◽  
Water Saturated ◽  
And Control ◽  
Isocapnic Hyperpnea

We tested the hypothesis that tachykinins mediate hyperpnea-induced bronchoconstriction (HIB) in 28 guinea pigs. Stimulus-response curves to increasing minute ventilation with dry gas were generated in animals depleted of tachykinins by capsaicin pretreatment and in animals pretreated with phosphoramidon, a neutral metalloendopeptidase inhibitor. Sixteen anesthetized guinea pigs received capsaicin (50 mg/kg sc) after aminophylline (10 mg/kg ip) and terbutaline (0.1 mg/kg sc). An additional 12 animals received saline (1 ml sc) instead of capsaicin. One week later, all animals were anesthetized, given propranolol (1 mg/kg iv), and mechanically ventilated (6 ml/kg, 60 breaths/min, 50% O2 in air fully water saturated). Phosphoramidon (0.5 mg iv) was administered to five of the noncapsaicin-treated guinea pigs. Eucapnic dry gas (95% O2–5% CO2) hyperpnea “challenges” were performed by increasing the tidal volume (2–6 ml) and frequency (150 breaths/min) for 5 min. Capsaicin-pretreated animals showed marked attenuation in HIB, with a rightward shift of the stimulus-response curve compared with controls; the estimated tidal volume required to elicit a twofold increase in respiratory system resistance (ES200) was 5.0 ml for capsaicin-pretreated animals vs. 3.7 ml for controls (P less than 0.03). Phosphoramidon-treated animals were more reactive to dry gas hyperpnea compared with control (ES200 = 2.6 ml; P less than 0.0001). Methacholine dose-response curves (10(-11) to 10(-7) mol iv) obtained at the conclusion of the experiments were similar among capsaicin, phosphoramidon, and control groups. These findings implicate tachykinin release as an important mechanism of HIB in guinea pigs.

Relationship between Cr and breathing pattern in mechanically ventilated patients

1994 ◽  
Vol 77 (6) ◽  
pp. 2703-2708 ◽  
Author(s):  
H. Burnet ◽  
M. Bascou-Bussac ◽  
C. Martin ◽  
Y. Jammes
Keyword(s):  
Linear Regression ◽  
Tidal Volume ◽  
Multiple Linear Regression ◽  
Breathing Pattern ◽  
Minute Ventilation ◽  
Respiratory Frequency ◽  
Upper Airways ◽  
Mechanically Ventilated ◽  
Mechanically Ventilated Patients ◽  
Ventilated Patients

In mechanically ventilated patients the natural gas-conditioning process of the upper airways is bypassed by the use of an endotracheal tube or a tracheostomy. We hypothesized that under these conditions the breathing pattern may greatly influence the convective respiratory heat loss (Cr). Cr values were computed from minute ventilation (VE) and inspiratory and expiratory gas temperatures, which were measured in six patients under mechanical ventilation for the management of cranial trauma. In each patient the effects of 11–20 different breathing patterns were investigated. Relationships between Cr and VE and between combined tidal volume and respiratory frequency were obtained by simple and multiple linear regression methods, respectively. Comparison of the standard errors of estimate indicated that multiple linear regression gives the best fit. Thus, Cr was highly dependent on the breathing pattern and was not related only to VE. For the same VE value, Cr was higher when VE was achieved with high tidal volume and low respiratory frequency. These data are consistent with previous studies in which thermal exchanges through the upper airways were taxed by hyperventilation of frigid air.

scholarly journals An optimized method for the estimation of the respiratory rate from electrocardiographic signals: implications for estimating minute ventilation

2014 ◽  
Vol 307 (3) ◽  
pp. H437-H447 ◽  
Author(s):  
Eric H. Weiss ◽  
Omid Sayadi ◽  
Priya Ramaswamy ◽  
Faisal M. Merchant ◽  
Naveen Sajja ◽  
...  
Keyword(s):  
Right Ventricular ◽  
Respiratory Rate ◽  
Coronary Sinus ◽  
Body Surface ◽  
Minute Ventilation ◽  
Left Ventricular ◽  
Accurate Estimation ◽  
Swine Model ◽  
Power Spectral ◽  
Ecg Leads

It is well-known that respiratory activity influences electrocardiographic (ECG) morphology. In this article we present a new algorithm for the extraction of respiratory rate from either intracardiac or body surface electrograms. The algorithm optimizes selection of ECG leads for respiratory analysis, as validated in a swine model. The algorithm estimates the respiratory rate from any two ECG leads by finding the power spectral peak of the derived ratio of the estimated root-mean-squared amplitude of the QRS complexes on a beat-by-beat basis across a 32-beat window and automatically selects the lead combination with the highest power spectral signal-to-noise ratio. In 12 mechanically ventilated swine, we collected intracardiac electrograms from catheters in the right ventricle, coronary sinus, left ventricle, and epicardial surface, as well as body surface electrograms, while the ventilation rate was varied between 7 and 13 breaths/min at tidal volumes of 500 and 750 ml. We found excellent agreement between the estimated and true respiratory rate for right ventricular ( R2 = 0.97), coronary sinus ( R2 = 0.96), left ventricular ( R2 = 0.96), and epicardial ( R2 = 0.97) intracardiac leads referenced to surface lead ECGII. When applied to intracardiac right ventricular-coronary sinus bipolar leads, the algorithm exhibited an accuracy of 99.1% ( R2 = 0.97). When applied to 12-lead body surface ECGs collected in 4 swine, the algorithm exhibited an accuracy of 100% ( R2 = 0.93). In conclusion, the proposed algorithm provides an accurate estimation of the respiratory rate using either intracardiac or body surface signals without the need for additional hardware.

Raising end-expiratory volume relieves air hunger in mechanically ventilated healthy adults

2007 ◽  
Vol 103 (3) ◽  
pp. 779-786 ◽  
Author(s):  
A. Vovk ◽  
A. P. Binks
Keyword(s):  
Tidal Volume ◽  
Minute Ventilation ◽  
Stretch Receptor ◽  
Positive End Expiratory Pressure ◽  
Analog Scale ◽  
Mechanically Ventilated ◽  
Shifting Baseline ◽  
Cycle Amplitude ◽  
End Tidal ◽  
Pulmonary Stretch Receptor

Air hunger is an unpleasant urge to breathe and a distressing respiratory symptom of cardiopulmonary patients. An increase in tidal volume relieves air hunger, possibly by increasing pulmonary stretch receptor cycle amplitude. The purpose of this study was to determine whether increasing end-expiratory volume (EEV) also relieves air hunger. Six healthy volunteers (3 women, 31 ± 4 yr old) were mechanically ventilated via a mouthpiece (12 breaths/min, constant end-tidal Pco2) at high minute ventilation (V̇e; 12 ± 2 l/min, control) and low V̇e (6 ± 1 l/min, air hunger). EEV was raised to ∼150, 400, 725, and 1,000 ml by increasing positive end-expiratory pressure (PEEP) to 2, 4, 6, and 8 cmH2O, respectively, for 1 min during high and low V̇e. The protocol was repeated with the subjects in the seated and supine positions to test for the effect of shifting baseline EEV. Air hunger intensity was rated at the end of each breath on a visual analog scale. The increase in EEV was the same in the seated and supine positions; however, air hunger was reduced to a greater extent in the seated position (13, 30, 31, and 44% seated vs. 3, 9, 23, and 27% supine at 2, 4, 6, and 8 cmH2O PEEP, respectively, P < 0.05). Removing PEEP produced a slight increase in air hunger that was greater than pre-PEEP levels ( P < 0.05). Air hunger is relieved by increases in EEV and tidal volume (presumably via an increase in mean pulmonary stretch receptor activity and cycle amplitude, respectively).

Effect of tidal volume on distribution of ventilation assessed by synchrotron radiation CT in rabbit

2004 ◽  
Vol 96 (5) ◽  
pp. 1899-1908 ◽  
Author(s):  
L. Porra ◽  
S. Monfraix ◽  
G. Berruyer ◽  
G. Le Duc ◽  
C. Nemoz ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Tidal Volume ◽  
Body Position ◽  
Minute Ventilation ◽  
Lung Ventilation ◽  
Mechanically Ventilated ◽  
Normal Distributions ◽  
Discrimination Ability ◽  
Proportional Increase ◽  
Log Normal

A respiration-gated synchrotron radiation computed tomography (SRCT) technique, which allows visualization and direct quantification of inhaled stable xenon gas, was used to study the effect of tidal volume (Vt) on regional lung ventilation. High-resolution maps (pixel size 0.35 × 0.35 mm) of local washin time constants (τ) and regional specific ventilation were obtained in five anesthetized, paralyzed, and mechanically ventilated rabbits in upright body position at the fourth, sixth, and eighth dorsal vertebral levels with a Vt from 4.9 ± 0.3 to 7.9 ± 0.4 ml/kg (means ± SE). Increasing Vt without an increase in minute ventilation resulted in a proportional increase of mean specific ventilation up to 65% in all studied lung levels and reduced the scattering of washin τ values. The τ values had log-normal distributions. The results indicate that an increase in Vt decreases nonuniformity of intraregional ventilatory gas exchange. The findings suggest that (SRCT) provides a new quantitative tool with high spatial discrimination ability for assessment of changes in peripheral pulmonary gas distribution during mechanical ventilation.

Ventilatory response to hypoxia in unanesthetized newborn kittens

1988 ◽  
Vol 64 (6) ◽  
pp. 2544-2551 ◽  
Author(s):  
H. Rigatto ◽  
C. Wiebe ◽  
C. Rigatto ◽  
D. S. Lee ◽  
D. Cates
Keyword(s):  
Tidal Volume ◽  
Chest Wall ◽  
Ventilatory Response ◽  
Minute Ventilation ◽  
Respiratory Frequency ◽  
Quiet Sleep ◽  
Newborn Kitten ◽  
Peripheral Mechanism ◽  
Flow Through ◽  
Ventilatory Response To Hypoxia

We studied the ventilatory response to hypoxia in 11 unanesthetized newborn kittens (n = 54) between 2 and 36 days of age by use of a flow-through system. During quiet sleep, with a decrease in inspired O2 fraction from 21 to 10%, minute ventilation increased from 0.828 +/- 0.029 to 1.166 +/- 0.047 l.min-1.kg-1 (P less than 0.001) and then decreased to 0.929 +/- 0.043 by 10 min of hypoxia. The late decrease in ventilation during hypoxia was related to a decrease in tidal volume (P less than 0.001). Respiratory frequency increased from 47 +/- 1 to 56 +/- 2 breaths/min, and integrated diaphragmatic activity increased from 14.9 +/- 0.9 to 20.2 +/- 1.4 arbitrary units; both remained elevated during hypoxia (P less than 0.001). Younger kittens (less than 10 days) had a greater decrease in ventilation than older kittens. These results suggest that the late decrease in ventilation during hypoxia in the newborn kitten is not central but is due to a peripheral mechanism located in the lungs or respiratory pump and affecting tidal volume primarily. We speculate that either pulmonary bronchoconstriction or mechanical uncoupling of diaphragm and chest wall may be involved.

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.

scholarly journals Impact of cervical spinal cord contusion on the breathing pattern across the sleep-wake cycle in the rat

2019 ◽  
Vol 126 (1) ◽  
pp. 111-123 ◽  
Author(s):  
Kun-Ze Lee
Keyword(s):  
Spinal Cord ◽  
Tidal Volume ◽  
Spinal Injury ◽  
Cervical Spinal Cord ◽  
Minute Ventilation ◽  
Respiratory Frequency ◽  
Breathing Patterns ◽  
Cord Injury ◽  
Spinal Contusion ◽  
Cervical Spinal Injury

The present study was designed to investigate breathing patterns across the sleep-wake state following a high cervical spinal injury in rats. The breathing patterns (e.g., respiratory frequency, tidal volume, and minute ventilation), neck electromyogram, and electroencephalography of unanesthetized adult male rats were measured at the acute (i.e., 1 day), subchronic (i.e., 2 wk), and/or chronic (i.e., 6 wk) injured stages after unilateral contusion of the second cervical spinal cord. Cervical spinal cord injury caused a long-term reduction in the tidal volume but did not influence the sleep-wake cycle duration. The minute ventilation during sleep was usually lower than that during the wake period in uninjured animals due to a decrease in respiratory frequency. However, this sleep-induced reduction in respiratory frequency was not observed in contused animals at the acute injured stage. By contrast, the tidal volume was significantly lower during sleep in contused animals but not uninjured animals from the acute to the chronic injured stage. Moreover, the frequency of sigh and postsigh apnea was elevated in acutely contused animals. These results indicated that high cervical spinal contusion is associated with exacerbated sleep-induced attenuation of the tidal volume and higher occurrence of sleep apnea, which may be detrimental to respiratory functional recovery after cervical spinal cord injury. NEW & NOTEWORTHY Cervical spinal injury is usually associated with sleep-disordered breathing. The present study investigated breathing patterns across sleep-wake state following cervical spinal injury in the rat. Unilateral cervical spinal contusion significantly impacted sleep-induced alteration of breathing patterns, showing a blunted frequency response and exacerbated attenuated tidal volume and occurrence of sleep apnea. The result enables us to investigate effects of cervical spinal injury on the pathogenesis of sleep-disordered breathing and evaluate potential therapies to improve respiration.

Effects of nasal positive-pressure hyperventilation on the glottis in normal awake subjects

1995 ◽  
Vol 79 (1) ◽  
pp. 176-185 ◽  
Author(s):  
V. Jounieaux ◽  
G. Aubert ◽  
M. Dury ◽  
P. Delguste ◽  
D. O. Rodenstein
Keyword(s):  
Tidal Volume ◽  
Positive Pressure Ventilation ◽  
Anterior Commissure ◽  
Minute Ventilation ◽  
Intermittent Positive Pressure Ventilation ◽  
Positive Pressure ◽  
Vocal Cords ◽  
Diaphragmatic Muscle ◽  
Inspiratory Resistance ◽  
Cyclic Changes

We have recently observed obstructive apneas during nasal intermittent positive-pressure ventilation (nIPPV) and suggested that they were due to hypocapnia-induced glottic closure. To confirm this hypothesis, we studied seven healthy subjects and submitted them to nIPPV while their glottis was continuously monitored through a fiber-optic bronchoscope. During wakefulness, we measured breath by breath the widest inspiratory angle formed by the vocal cords at the anterior commissure along with several other indexes. Mechanical ventilation was progressively increased up to 30 l/min. In the absence of diaphragmatic activity, increases in delivered minute ventilation resulted in progressive narrowing of the vocal cords, with an increase in inspiratory resistance and a progressive reduction in the percentage of the delivered tidal volume effectively reaching the lungs. Adding CO2 to the inspired gas led to partial widening of the glottis in two of three subjects. Moreover, activation of the diaphragmatic muscle was always associated with a significant inspiratory abduction of the vocal cords. Sporadically, complete adduction of the vocal cords was directly responsible for obstructive laryngeal apneas and cyclic changes in the glottic aperture resulted in waxing and waning of tidal volume. We conclude that in awake humans passive ventilation with nIPPV results in vocal cord adduction that depends partly on hypocapnia, but our results suggest that other factors may also influence glottic width.

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)

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