BACKGROUND Electrical impedance tomography measures changes in lung impedance, which are mainly related to changes in lung volume. We used electrical impedance tomography to investigate the effects of high-flow nasal cannula (HFNC) and body position on global and regional end-expiratory lung impedance variation (ΔEELI). METHODS Prospective study with 20 healthy adults. Two periods were define...

INTRODUCTION Tracheotomy is widely performed in the intensive care unit after long-term oral intubation. The present study investigates the immediate influence of tracheotomy on respiratory mechanics and blood gases during mechanical ventilation. METHODS Tracheotomy was performed in 32 orally intubated patients for 10.5 +/- 4.66 days (all results are means +/- standard deviations). Airway pre...

The effects of hypercapnia and hypocapnia on respiratory resistance were studied in 15 healthy subjects and 30 asthmatic subjects. Respiratory resistance (impedance) was measured with the pseudo-random noise forced oscillation technique while the subjects rebreathed from a wet spirometer in a closed respiratory circuit in which end tidal carbon dioxide tension (PCO2) could be controlled. Hyperc...

1) Use of the complex wave oscillation method provided a measurement range of over 9 cmH201lls with a resolution of O.18 cmH20/1ls. 2) The respiratory system was expressed as a two-compartment model. By expressing the circuit characteristics as phasor loci, a method was shown whereby individual impedance parameter values could be derived frorn the measured impedance phasor loci. S) Vnder enflur...

When input impedance is determined by means of the forced oscillation technique, part of the oscillatory flow measured at the mouth is lost in the motion of the upper airway wall acting as a shunt. This is avoided by applying the oscillations around the subject's head (head generator) rather than at the mouth (conventional technique). In seven wheezing infants, we compared both techniques to es...

In this paper, we present a new pipeline for the fast and accurate segmentation of impedance images of the lungs using electrical impedance tomography (EIT). EIT is an emerging, promising, non-invasive imaging modality that produces real-time, low spatial but high temporal resolution images of impedance inside a body. Recovering impedance itself constitutes a nonlinear ill-posed inverse problem...

BACKGROUND Head-of-bed elevation (HOBE) has been shown to assist in reducing respiratory complications associated with mechanical ventilation; however, there is minimal research describing changes in end-expiratory lung volume. This study aims to investigate changes in end-expiratory lung volume in a supine position and 2 levels of HOBE. METHODS Twenty postoperative cardiac surgery subjects w...

Previous work investigating respiratory system mechanics in mice has reported an aging-related increase in compliance and mean linear intercept (Lm). However, these changes were assessed using only a young (2-mo-old) and old (20- and 26-mo-old) group yet were interpreted to reflect a linear evolution across the life span. Therefore, to investigate respiratory system mechanics and lung morphomet...

Antenatal exposure to intra-amniotic (i.a.) endotoxin initiates a complex series of events, including an inflammatory cascade, increased surfactant production, and alterations to lung structure. Using the low frequency forced oscillation technique as a sensitive tool for measurement of respiratory impedance, we aimed to determine which factors contributed most to measured changes in lung mechan...

OBJECTIVE To correlate anthropometric data and respiratory muscle strength (RMS) of normal-weight and obese women. METHODS The sample consisted of 103 sedentary women, divided into two groups: 57 obese and 46 normal-weight women. Waist circumference (WC) and hip circumference (HC) were measured to calculate the waist-to-hip ratio (WHR), and maximal respiratory pressures (Pmax) were determined...