Volume-targeted ventilation with a Fabian ventilator: maintenance of tidal volumes and blood CO2

2019 ◽  
Vol 105 (3) ◽  
pp. 253-258 ◽  
Author(s):  
Gusztav Belteki ◽  
András Széll ◽  
Lajos Lantos ◽  
Gabor Kovács ◽  
Gyula Szántó ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Endotracheal Tube ◽  
Sampling Rate ◽  
Inverse Correlation ◽  
Blood Gases ◽  
Minute Volume ◽  
Absolute Difference ◽  
Interhospital Transfer ◽  
Data Points ◽  
Median Absolute Difference

ObjectiveTo analyse the performance of the Fabian +NCPAP evolution ventilator during volume guarantee (VG) ventilation in neonates at maintaining the target tidal volume and what tidal and minute volumes are required to maintain normocapnia.MethodsClinical and ventilator data were collected and analysed from 83 infants receiving VG ventilation during interhospital transfer. Sedation was used in 26 cases. Ventilator data were downloaded with a sampling rate of 0.5 Hz. Data were analysed using the Python computer language and its data analysis packages.Results~107 hours of ventilator data were analysed, consisting of ~194 000 data points. The median absolute difference between the actual expiratory tidal volume (VTe) of the ventilator inflations and the target tidal volume (VTset) was 0.29 mL/kg (IQR: 0.11–0.79 mL/kg). Overall, VTe was within 1 mL/kg of VTset in 80% of inflations. VTe decreased progressively below the target when the endotracheal tube leak exceeded 50%. When leak was below 50%, VTe was below VTset by >1 mL/kg in less than 12% of inflations even in babies weighing less than 1000 g. Both VTe (r=−0.34, p=0.0022) and minute volume (r=−0.22, p=0.0567) showed a weak inverse correlation with capillary partial pressure of carbon dioxide (Pco2) values. Only 50% of normocapnic blood gases were associated with tidal volumes between 4 and 6 mL/kg.ConclusionsThe Fabian ventilator delivers volume-targeted ventilation with high accuracy if endotracheal tube leakage is not excessive and the maximum allowed inflating pressure does not limit inflations. There is only weak inverse correlation between tidal or minute volumes and Pco2.

High-frequency oscillatory ventilation with volume guarantee: a single-centre experience

2018 ◽  
pp. fetalneonatal-2018-315490 ◽  
Author(s):  
Gusztav Belteki ◽  
Colin J Morley
Keyword(s):  
Tidal Volume ◽  
High Frequency ◽  
Clinical Care ◽  
Sampling Rate ◽  
Inverse Correlation ◽  
Blood Gases ◽  
High Frequency Oscillatory Ventilation ◽  
Poor Correlation ◽  
Oscillatory Ventilation ◽  
High Frequency Oscillatory

ObjectiveHigh-frequency oscillatory ventilation (HFOV) is widely used in neonatology. The Dräger Babylog VN500 ventilator offers volume-guaranteed HFOV (HFOV-VG) mode when the high-frequency tidal volume (VThf) to be delivered can be set. We investigated how HFOV-VG maintains VThf in the short and longer term and how it affects other ventilator parameters and blood gases.MethodsWe downloaded ~3.2 million seconds (36.7 days) of ventilator data from 17 infants ventilated using HFOV-VG during clinical care with 1 Hz sampling rate. To process and analyse the data, we used the Python computer language.ResultsOverall, the median VThf was 1.93 mL/kg (IQR 1.64–2.45 mL/kg). The difference between set and delivered tidal volume was <0.2 mL/kg for 83% of time. In the individual recordings, the median VThf ranged between 1.44 and 3.31 mL/kg. During HFOV-VG, the VThf varied from 1 second to another, but it was very close to the target value when averaged over 5 min periods. After weight correction, the VThf or the diffusion coefficient of carbon dioxide (DCO2) showed weak inverse correlation with partial pressure of CO2(pCO2) (for VThf, r=−0.162, 95% CI −0.282 to –0.037, p=0.01). Uncorrected values showed no correlation. Of the 53 blood gas measurements taken when VThf was >2.5 mL/kg, there were only six (11%) with a pCO2 >8 kPa.ConclusionsDuring HFOV-VG, the tidal volume of oscillations varies in the short term but is maintained very close to the target over the longer term. VThf or DCO2 have poor correlation with CO2 levels but a volume of >2.5 mL/kg VThf is rarely needed.

Inspiratory airway CO2 loading in the pony

1984 ◽  
Vol 57 (4) ◽  
pp. 1097-1103 ◽  
Author(s):  
H. W. Shirer ◽  
J. A. Orr ◽  
J. L. Loker
Keyword(s):  
Tidal Volume ◽  
Dead Space ◽  
Blood Gases ◽  
Minute Volume ◽  
Arterial Pco2 ◽  
Arterial Blood Gas ◽  
Arterial Blood ◽  
Airway Dead Space ◽  
Arterial Po2 ◽  
Stimulation Of

To determine if CO2-sensitive airway receptors are important in the control of breathing, CO2 was preferentially loaded into the respiratory airways in conscious ponies. The technique involved adding small amounts of 100% CO2 to either the latter one-third or latter two-thirds of the inspiratory air in an attempt to raise CO2 concentrations in the airway dead space independent of the arterial blood. Arterial blood gas tensions (PCO2 and PO2) and pH, as well as respiratory output (minute volume, tidal volume, and respiratory rate), were measured in a series of 20 experiments on 5 awake ponies. Elevation of airway CO2 to approximately 12% by addition of CO2 to the latter portion of the inspiratory tidal volume did not alter either ventilation or arterial blood gases. When CO2 was added earlier in the inspiratory phase to fill more of the airway dead space, a small but significant increase in minute volume (2.1 l X min-1 X m-2) and tidal volume (0.1 l X m-2) was accompanied by an increase in arterial PCO2, arterial PO2, and a fall in pH (0.96 Torr, 10.5 Torr, 0.007 units, respectively). A second series of 12 experiments on 6 awake ponies using radiolabeled 14CO2 determined that the increases in breathing were minimal when compared with the large increase that occurred when these animals inhaled 6% 14CO2 (12.7 l X min-1 X m-2). Also, stimulation of systemic arterial or central nervous system chemoreceptors cannot be eliminated from the response since significant amounts of 14CO2 were present in the arterial blood when this marker gas was added to the latter two-thirds of the inspiratory tidal volume. The results, therefore, provide no evidence for CO2-sensitive airway receptors that can increase breathing when stimulated during the latter part of the inspiratory cycle.

scholarly journals Evaluation of point-of-care glucose testing accuracy using locally-smoothed median absolute difference curves

2008 ◽  
Vol 389 (1-2) ◽  
pp. 31-39 ◽  
Author(s):  
Gerald J. Kost ◽  
Nam K. Tran ◽  
Victor J. Abad ◽  
Richard F. Louie
Keyword(s):  
Point Of Care ◽  
Absolute Difference ◽  
Glucose Testing ◽  
Testing Accuracy ◽  
Median Absolute Difference

scholarly journals RESPIRATORY AND SYMPTOMATIC IMPACT OF ASCITES RELIEF BY PARACENTESIS IN PATIENTS WITH HEPATIC CIRRHOSIS

2020 ◽  
Vol 57 (1) ◽  
pp. 64-68
Author(s):  
Verônica Lourenço WITTMER ◽  
Rozy Tozetti LIMA ◽  
Michele Coutinho MAIA ◽  
Halina DUARTE ◽  
Flávia Marini PARO
Keyword(s):  
Liver Cirrhosis ◽  
Tidal Volume ◽  
Hepatic Cirrhosis ◽  
Blood Pressure Reduction ◽  
Vital Signs ◽  
Meld Score ◽  
Minute Volume ◽  
Respiratory Pattern ◽  
Peripheral Oxygen Saturation ◽  
The Impact

ABSTRACT BACKGROUND: Liver cirrhosis is a highly prevalent disease that, at an advanced stage, usually causes ascites and associated respiratory changes. However, there are few studies evaluating and quantifying the impact of ascites and its relief through paracentesis on lung function and symptoms such as fatigue and dyspnea in cirrhotic patients. OBJECTIVE: To assess and quantify the impact of acute reduction of ascitic volume on respiratory parameters, fatigue and dyspnea symptoms in patients with hepatic cirrhosis, as well as to investigate possible correlations between these parameters. METHODS: Thirty patients with hepatic cirrhosis and ascites who underwent the following pre and post paracentesis evaluations: vital signs, respiratory pattern, thoracoabdominal mobility (cirtometry), pulmonary function (ventilometry), degree of dyspnea (numerical scale) and fatigue level (visual analog scale). RESULTS: There was a higher prevalence of patients classified as CHILD B and the mean MELD score was 14.73±5.75. The comparison of pre and post paracentesis parameters evidenced after paracentesis: increase of predominantly abdominal breathing pattern, improvement of ventilatory variables, increase of the differences obtained in axillary and abdominal cirtometry, reduction of dyspnea and fatigue level, blood pressure reduction and increased peripheral oxygen saturation. Positive correlations found: xiphoid with axillary cirtometry, degree of dyspnea with fatigue level, tidal volume with minute volume, Child “C” with higher MELD score, volume drained in paracentesis with higher MELD score and with Child “C”. We also observed a negative correlation between tidal volume and respiratory rate. CONCLUSION: Since ascites drainage in patients with liver cirrhosis improves pulmonary volumes and thoracic expansion as well as reduces symptoms such as fatigue and dyspnea, we can conclude that ascites have a negative respiratory and symptomatological impact in these patients.

The Effect of Posture on Ventilation and Lung Mechanics in Preterm and Light-for-Date Infants

PEDIATRICS ◽  
1979 ◽  
Vol 64 (4) ◽  
pp. 429-432 ◽  
Author(s):  
Alastair A. Hutchison ◽  
Keith R. Ross ◽  
George Russell
Keyword(s):  
Tidal Volume ◽  
Prone Position ◽  
Supine Position ◽  
Work Of Breathing ◽  
Newborn Infants ◽  
Lateral Position ◽  
Minute Volume ◽  
Lung Mechanics ◽  
Total Work ◽  
Preterm Group

The effect of right lateral, supine, and prone postures on ventilation and lung mechanics was studied in 23 healthy newborn infants, ten preterm and 13 term, "light-for-date." In the preterm group, tidal volume, minute volume, elastic work, inspiratory viscous work, total viscous work, and the total work of breathing were significantly greater in the prone position than in the supine position. Results obtained in the lateral position did not differ significantly from those in the prone or supine positions. Posture did not significantly affect tidal volume or lung mechanics in the light-for-date infants. The prone position is suggested to be the optimum nursing posture for healthy preterm infants.

On Replacing the Surfactant

PEDIATRICS ◽  
1980 ◽  
Vol 65 (6) ◽  
pp. 1176-1177
Author(s):  
Mary Ellen Avery
Keyword(s):  
Endotracheal Tube ◽  
Blood Gases ◽  
Hyaline Membrane Disease ◽  
Surfactant Deficiency ◽  
Hyaline Membrane ◽  
Surface Active ◽  
Artificial Surfactant ◽  
Patent Ductus

Ever since it was realized that hyaline membrane disease was the consequence of surfactant deficiency, replacing the missing surface-active alveolar lining layer has been a tantalizing prospect. The report of Fujiwara et al1 is the first demonstration in the human of consistent and dramatic success after a single instillation of an artificial surfactant by way of an endotracheal tube. The prompt restoration of a stable alveolar lining layer and the impressive improvement in blood gases are well documented. The problem of the widely patent ductus producing difficulties in the subsequent days is expected and of course could be approached by other interventions.

Integration of chemoreceptor stimuli by caudal pontile and rostral medullary sites

1976 ◽  
Vol 41 (5) ◽  
pp. 612-622 ◽  
Author(s):  
W. M. St John ◽  
S. C. Wang
Keyword(s):  
Tidal Volume ◽  
Minute Volume ◽  
Respiratory Frequency ◽  
Primary Role ◽  
Frequency Responses ◽  
Radiofrequency Lesions ◽  
Pneumotaxic Center ◽  
Definition Of ◽  
Decerebrate Cats ◽  
Paco2 Level

Ventilatory regulation by pontile pneumotaxic and apneustic centers and by rostral medullary sites was evaluated in intercollicular decerebrate cats. Following pneumotaxic center ablation, PAco2 was significantly elevated.Moreover, in response to hypercapina or hypoxia, frequency responses were significantly diminished whereas tidal volume responses were unchanged or elevated. Interruption of apneustic center function by caudal pontile transection or radiofrequency lesions in the caudal pons and/or rostral medulla resulted in significant decreases of tidal volume responses and significant elevations of frequency responses to both hypercapnia and hypoxia. Neither minute volume responses nor the PAco2 level was altered. It is concluded that the apneustic center exercises a primary role in the brainstem definitionof tidal volume responses for both peripheral and central chemoreceptor afferent stimuli. The apneustic center is also considered to exert an impoetant function in the definition of respiratory frequency. A medially placed pathway in the rostral medulla is proposed to interconnect the apneustic center with the medullary respiratory nuclei.

Naloxone alters the early response to an inspiratory flow-resistive load

1989 ◽  
Vol 67 (5) ◽  
pp. 1747-1753 ◽  
Author(s):  
A. T. Scardella ◽  
T. V. Santiago ◽  
N. H. Edelman
Keyword(s):  
Tidal Volume ◽  
Blood Gases ◽  
Inspiratory Flow ◽  
Abdominal Muscles ◽  
Base Line ◽  
Resistive Load ◽  
Endogenous Opioid ◽  
Transdiaphragmatic Pressure ◽  
Arterial Blood ◽  
Gastric Pressure

In a previous study in unanesthetized goats, we demonstrated that cerebrospinal fluid levels of beta-endorphin were significantly elevated after 2.5 h of inspiratory flow-resistive loading. Naloxone (NLX) (0.1 mg/kg) administration partially and transiently reversed the tidal volume depression seen during loading. In the current study, we tested the hypothesis that endogenous opioid elaboration results in depression of respiratory output to the diaphragm. In six studies of five unanesthetized goats, tidal volume (VT), transdiaphragmatic pressure (Pdi), diaphragmatic electromyogram (EMGdi), and arterial blood gases were monitored. A continuous NLX (0.1 mg/kg) or saline (SAL) infusion was begun 5 min before an inspiratory flow-resistive load of 120 cmH2O.l-1.s was imposed. Our data show that the depression of VT induced by the load was prevented by NLX as early as 15 min and persisted for 2 h. At 2 h, Pdi was still 294 +/- 45% of the base-line value compared with 217 +/- 35% during SAL. There was no difference in EMGdi between the groups at any time. However, the augmentation of Pdi was associated with a greater increase in end-expiratory gastric pressure in the NLX group. We conclude that the reduction in VT and Pdi associated with endogenous opioid elaboration is not mediated by a decrease in neural output to the diaphragm, but it appears to be the result of a decrease in respiratory output to the abdominal muscles.

Anesthesia alters the pattern of aerosol retention in hamsters

1983 ◽  
Vol 54 (1) ◽  
pp. 37-44 ◽  
Author(s):  
T. D. Sweeney ◽  
J. D. Brain ◽  
S. LeMott
Keyword(s):  
General Anesthesia ◽  
Tidal Volume ◽  
Total Lung Capacity ◽  
Minute Volume ◽  
Consistent Pattern ◽  
O2 Consumption ◽  
Pentobarbital Sodium ◽  
Lung Capacity ◽  
Syrian Golden Hamsters ◽  
Evenness Index

General anesthesia was used to produce nonventilated areas of the lung, and aerosol inhalation was used to locate these areas, assuming that no aerosol deposits in a nonventilated region. Male Syrian golden hamsters were anesthetized with pentobarbital sodium (90 mg/kg), which reduced respiratory frequency, tidal volume, minute volume, and O2 consumption to 61, 41, 24, and 36%, respectively, of the corresponding awake levels. Awake and anesthetized hamsters were exposed to the aerosol for 30 min; then the lungs were excised, dried at total lung capacity, sliced into sections, and dissected into pieces. Autoradiographs were made of slices, and the activity and weight of pieces were determined. The evenness index (EI), a measure of the uniformity of retention, was calculated for each piece. With complete uniformity of retention, all EI's would be 1.0. In awake animals, only 0.2% (by wt) of the lungs had little or no retention (EI's less than 0.20). More particles deposited in the apex than in the base of the lungs. General anesthesia for extended periods of time with no deep breaths alters ventilation and therefore the distribution of aerosol retention. Many regions of the lungs in the anesthetized animals received few or no particles (11.6% of lungs had EI less than 0.20); however, no consistent pattern was observed in the location of these areas from animal to animal. The apex-to-base gradient for retention in these animals was also reversed. Radioactive aerosols can be used as probes to indicate the extent and distribution of nonventilated areas in the lungs.

Failure of tracheal distension to inhibit breathing in anesthetized dogs

1980 ◽  
Vol 48 (5) ◽  
pp. 794-798 ◽  
Author(s):  
T. C. Lloyd ◽  
J. A. Cooper
Keyword(s):  
Tidal Volume ◽  
Lung Volume ◽  
Potential Role ◽  
Minute Volume ◽  
Abdominal Compression ◽  
Frequency Increase ◽  
Before And After ◽  
Anesthetized Dogs ◽  
Spontaneously Breathing

Using anesthetized spontaneously breathing dogs, we compared the respiratory effects of tracheal distension with the effects of changes in lung volume before and after vagotomy. We used an endotracheal tube with a long cuff to distend the trachea to pressures of 10, 20, and 40 cmH2O. Lung volume increases were imposed by expiratory threshold loading, and volume was decreased by abdominal compression, both of which caused outward rib cage displacement. During expiratory loading, the tidal volume was unchanged but respiratory frequency and minute volume fell and an active expiratory effort appeared; whereas frequency and minute volume rose, but tidal volume fell during abdominal compression. Tracheal distension evoked no discernible change in breathing. Following vagotomy, tidal volume and minute volume fell, and frequency rose slightly, during expiratory loading but abdominal compression was without effect. After vagotomy, 40 cmH2O tracheal distension caused a slight frequency increase. We concluded that the potential role of tracheal deformation in the reflex control of breathing is insignificant in comparison with the other airways.

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