Ventilatory saving by external chest wall compression or oral high-frequency oscillation in normal subjects and those with chronic airflow obstruction

1985 ◽  
Vol 69 (3) ◽  
pp. 349-359 ◽  
Author(s):  
R. J. D. George ◽  
R. J. D. Winter ◽  
S. J. Flockton ◽  
D. M. Geddes
Keyword(s):  
Chest Wall ◽  
High Frequency ◽  
Minute Ventilation ◽  
Airflow Obstruction ◽  
Normal Subjects ◽  
High Frequency Oscillation ◽  
Tidal Breathing ◽  
Frequency Oscillation ◽  
Resonant Frequencies ◽  
High Frequency Oscillations

1. Oscillation of the air within the lungs at high frequency is associated with an increased clearance of CO2. Because of the high frequency and low volume of these oscillations, spontaneous breathing is unhindered and the technique has potential value as a supplement to ventilation. 2. High-frequency oscillations were superimposed upon tidal breathing by using a loudspeaker attached to a mouthpiece (oral high-frequency oscillation, OHFO) or by external chest wall compression (ECWC). We set out (a) to compare the changes in ventilation and breathlessness by using OHFO and ECWC in normal subjects with those in patients with chronic airflow obstruction (CAO), and (b) to relate the pattern of saving to the resonant frequencies of the respiratory system as a whole (fOT, 5–10 Hz in normal subjects, 16–26 Hz in CAO) and those of the ribcage(foc,70 Hz). 3. OHFO reduced minute ventilation (VE) by up to 46% in normal subjects (P < 0.01) and 29% in CAO (P < 0.01) without any rise in CO2. ECWC reduced VE by 27% in normal subjects (P < 0.01) and 16% in CAO (P < 0.01) without a rise in CO2. 4. High-frequency oscillation by either method relieved breathlessness in those with CAO and was comfortable and well tolerated. 5. In normal subjects for was discrete and varied little with respiration. Maximum savings occurred around for (5–10 Hz). 6. In CAO, there was no obvious single resonant frequency and flow and pressure signals were intermittently in phase over a band of about 10 Hz. Thus the reductions in minute ventilation were only loosely related to for (13–26 Hz). Neither group reduced VE at foc (65–75 Hz). 7. OHFO has considerable potential in the management of patients with CAO, where it may be of value as an assistance to breathing and in the relief of breathlessness. ECWC, although effective in principle, is impractical by our methods and awaits the development of an acceptable delivery system.

Aerosol deposition in the human lung: Effect of high-frequency oscillation on the deposition characteristics of an inhaled nebulized aerosol

1988 ◽  
Vol 75 (5) ◽  
pp. 535-542 ◽  
Author(s):  
Simon H. L. Thomas ◽  
Jackie A. Langford ◽  
Robert J. D. George ◽  
Duncan M. Geddes
Keyword(s):  
Deposition Rate ◽  
High Frequency ◽  
Regional Distribution ◽  
Normal Subjects ◽  
Aerosol Deposition ◽  
High Frequency Oscillation ◽  
Particle Sizes ◽  
Frequency Oscillation ◽  
Regional Deposition ◽  
Peripheral Lung

1. Oral high-frequency oscillation (OHFO) may have important effects on aerosol deposition in the lungs. In order to investigate these, a technique was devised to measure regional deposition rates of a nebulized radio-labelled aerosol in the lungs during normal tidal breathing. 2. The effect of three frequencies of OHFO on pulmonary aerosol deposition rate (PADR) in four normal subjects and five patients with chronic airways obstruction (CAO) were assessed using the technique. 3. In separate experiments employing three normal subjects, the effect of OHFO was studied on the deposition rate of aerosol on the oropharynx and delivery apparatus, and on the amount and characteristics of aerosol inhaled by the subjects. 4. Total PADR was significantly reduced by OHFO at 8 Hz and 16 Hz in the normal subjects, and by all three frequencies of OHFO in the CAO patients. In the normal subjects, the regional distribution of aerosol deposition was unchanged, but in the CAO patients a larger proportion of total aerosol deposition occurred in peripheral lung. 5. OHFO reduced the oropharyngeal aerosol deposition rate, increased the loss of aerosol to the atmosphere before inhalation, and increased the deposition of aerosol on the delivery apparatus. The end result was a reduction in the amount of aerosol inhaled, and in the particle sizes measured at the mouthpiece. 6. We conclude that OHFO reduces the amount of aerosol inhaled, but may improve peripheral deposition of inhaled aerosol in patients with CAO. This effect may be of value in the clinical administration of nebulized drugs.

External High Frequency Oscillation in Normal Subjects and in Mechanically Ventilated Patients

1992 ◽  
Vol 82 (s26) ◽  
pp. 32P-32P
Author(s):  
N.M. Al-Saady ◽  
S.S.D. Fernando ◽  
A.R.C. Cummin ◽  
A.J. Petros ◽  
Z Hayek ◽  
...  
Keyword(s):  
High Frequency ◽  
Normal Subjects ◽  
High Frequency Oscillation ◽  
Frequency Oscillation ◽  
Mechanically Ventilated ◽  
Mechanically Ventilated Patients ◽  
Ventilated Patients

scholarly journals Scalp high-frequency oscillation rates are higher in younger children

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Dorottya Cserpan ◽  
Ece Boran ◽  
Santo Pietro Lo Biundo ◽  
Richard Rosch ◽  
Johannes Sarnthein ◽  
...  
Keyword(s):  
High Frequency ◽  
Signal To Noise Ratio ◽  
Paediatric Population ◽  
High Frequency Oscillation ◽  
Older Children ◽  
Frequency Oscillation ◽  
Scalp Eeg ◽  
High Frequency Oscillations ◽  
Median Test ◽  
Generalized Epilepsy

Abstract High-frequency oscillations in scalp EEG are promising non-invasive biomarkers of epileptogenicity. However, it is unclear how high-frequency oscillations are impacted by age in the paediatric population. We prospectively recorded whole-night scalp EEG in 30 children and adolescents with focal or generalized epilepsy. We used an automated and clinically validated high-frequency oscillation detector to determine ripple rates (80–250 Hz) in bipolar channels. Children &lt; 7 years had higher high-frequency oscillation rates (P = 0.021) when compared with older children. The median test−retest reliability of high-frequency oscillation rates reached 100% (iqr 50) for a data interval duration of 10 min. Scalp high-frequency oscillation frequency decreased with age (r = −0.558, P = 0.002), whereas scalp high-frequency oscillation duration and amplitude were unaffected. The signal-to-noise ratio improved with age (r = 0.37, P = 0.048), and the background ripple band activity decreased with age (r = −0.463, P = 0.011). We characterize the relationship of scalp high-frequency oscillation features and age in paediatric patients. EEG intervals of ≥10 min duration are required for reliable measurements of high-frequency oscillation rates. This study is a further step towards establishing scalp high-frequency oscillations as a valid epileptogenicity biomarker in this vulnerable age group.

External high frequency oscillation in normal subjects and in patients with acute respiratory failure

Anaesthesia ◽  
1995 ◽  
Vol 50 (12) ◽  
pp. 1031-1035 ◽  
Author(s):  
N. M. AL-SAADY ◽  
S. S. D. FERNANDO ◽  
A. J. PETROS ◽  
A. R. C. CUMMIN ◽  
V. S. SIDHU ◽  
...  
Keyword(s):  
Respiratory Failure ◽  
Acute Respiratory Failure ◽  
High Frequency ◽  
Normal Subjects ◽  
High Frequency Oscillation ◽  
Frequency Oscillation

scholarly journals Acoustic Correlatives of Chest Wall Volumetric Motion During High Frequency Oscillation (HFO). 1503

1997 ◽  
Vol 41 ◽  
pp. 253-253
Author(s):  
Mitchell Goldstein ◽  
Robert Kopotic ◽  
Wade Rich ◽  
Ricardo Liberman ◽  
John Vogt ◽  
...  
Keyword(s):  
Chest Wall ◽  
High Frequency ◽  
High Frequency Oscillation ◽  
Frequency Oscillation

scholarly journals Subcortical Hyperexcitability in Migraineurs: A High-Frequency Oscillation Study

2011 ◽  
Vol 38 (2) ◽  
pp. 309-316 ◽  
Author(s):  
Kuan-Lin Lai ◽  
Kwong-Kum Liao ◽  
Jong-Ling Fuh ◽  
Shuu-Jiun Wang
Keyword(s):  
High Frequency ◽  
Area Under Curve ◽  
Late Phase ◽  
Intracortical Inhibition ◽  
High Frequency Oscillation ◽  
Frequency Filter ◽  
Frequency Oscillation ◽  
High Frequency Oscillations ◽  
Subcortical Regions ◽  
And Control

Objective:An abnormal central nervous system excitability level was found in patients with migraine. Whether it is hyper- or hypo-excitable is still debated. This study aimed to compare the somatosensory high-frequency oscillations (HFOs), which reflected subcortical excitability (early phase) and intracortical inhibition (late phase), between patients with migraine and control subjects.Methods:HFOs were recorded from C3'-Fz, using a 500-1000 Hz frequency filter after stimulation at right median nerves at the wrists, and divided into early and late phases based on the N20 peak. Fifty-nine untreated patients (n=24 during ictal period; n=35, interictal) and 22 controls finished the study.Results:In early HFOs, patients both during ictal and interictal periods had higher maximal amplitudes (p =0.039) and area-under-curve (p =0.029) than those of the controls. Regarding the late HFOs, there were no significant differences among these groups.Conclusion:Our study suggests a hyper-excitable state in the subcortical regions in patients with migraine both during interictal and ictal periods.

High-Frequency Oscillation and Chronic Lung Disease in Very Low Birth Weight Infants

PEDIATRICS ◽  
2001 ◽  
Vol 108 (1) ◽  
pp. 212-214
Author(s):  
J. P. Shenai; ◽  
P. Rimensberger; ◽  
U. Thome ◽  
F. Pohlandt; ◽  
P. Rimensberger
Keyword(s):  
Birth Weight ◽  
Low Birth Weight ◽  
Lung Disease ◽  
Chronic Lung Disease ◽  
High Frequency ◽  
Very Low Birth Weight ◽  
High Frequency Oscillation ◽  
Frequency Oscillation ◽  
Low Birth Weight Infants
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