Search results for "breathing"
showing 10 items of 319 documents
Oral breathing and head posture
2006
Abstract Objective: To determine the head posture and cephalometric characteristics in oral breathing children. Materials and Methods: Lateral cephalograms taken in natural head posture of 35 oral breathing patients (OB) (mean age 8.8 ± 2.2 years SD; range 5–13 years) and of 35 patients with varied malocclusions and physiological breathing (PB) (mean age 9.7 ± 1.6 years SD; range 7–13 years) were examined. Results: A Student's t-test showed that an increase in angles NSL/OPT (P = .000), NSL/CVT (P = .001), FH/OPT (P = .000), FH/CVT (P = .005), and NSL/VER (P = .000); a decrease in the distance MGP-CV1p (P = .0001); and a decrease in the angles MGP/OP (P = .000) and OPT/ CVT (P = .036) were …
Non-invasive ventilation effectiveness and the effect of ventilatory mode on survival in ALS patients.
2013
Non-invasive ventilation (NIV) prolongs survival in amyotrophic lateral sclerosis (ALS), but there are no data with which to compare the effectiveness of the different ventilator modes – volume (Vol-NIV) or pressure-cycled (Pres-NIV) ventilation – in ALS. We aimed to determine whether the ventilatory mode has an effect on ventilation effectiveness and survival of ALS patients using NIV. We used a retrospective study that included all ALS patients for whom NIV was indicated in two referral units: one using Vol-NIV and the other using Pres-NIV. Demographic, functional and nocturnal gas exchange parameters at NIV initiation were recorded. Eighty-two ALS patients ventilated using Pres-NIV and 6…
Propofol sedation reduces diaphragm activity in spontaneously breathing patients: ultrasound assessment.
2017
BACKGROUND: The diaphragm is the most important respiratory muscle in humans, and the close relationship between inspired volume and diaphragmatic movement in normal subjects has led to investigations into diaphragmatic activity using ultrasound, during spontaneous breathing and sedative drug infusion. METHODS: A total of 36 consecutive patients undergoing diagnostic procedures under deep propofol sedation were studied. Ultrasound measurements included the following: diaphragmatic thickening end-inspiration (TEI) and endexpiration (TEE). Diaphragmatic thickening fraction (DTF) was calculated from [(TEI TEE) / TEE] at various time points (at T0 basal; at T1 during propofol infusion; at T2 aw…
Cerebral blood flow autoregulation during hypobaric hypotension assessed by laser Doppler scanning.
1994
Hypobaric hypotension was used to reduce systemic blood pressure in rats below the lower threshold of CBF autoregulation to evaluate a new laser Doppler (LD) “scanning” technique. Spontaneously breathing male Wistar Kyoto rats (n = 8) were anesthetized with chloral hydrate and the head fixed in a stereotaxic head holder. A cranial window with intact dura mater was introduced to assess local CBF (lCBF) by LD. One stationary probe served to detect rapid flow changes, whereas the second probe was used to sample lCBF recordings from many cortical locations by means of a stepping motor-controlled micromanipulator to obtain lCBF frequency histograms. Advantages are an improved spatial resolution…
High flow nasal therapy versus noninvasive ventilation as initial ventilatory strategy in COPD exacerbation: a multicenter non-inferiority randomized…
2020
Abstract Background The efficacy and safety of high flow nasal therapy (HFNT) in patients with acute hypercapnic exacerbation of chronic obstructive pulmonary disease (AECOPD) are unclear. Our aim was to evaluate the short-term effect of HFNT versus NIV in patients with mild-to-moderate AECOPD, with the hypothesis that HFNT is non-inferior to NIV on CO2 clearance after 2 h of treatment. Methods We performed a multicenter, non-inferiority randomized trial comparing HFNT and noninvasive ventilation (NIV) in nine centers in Italy. Patients were eligible if presented with mild-to-moderate AECOPD (arterial pH 7.25–7.35, PaCO2 ≥ 55 mmHg before ventilator support). Primary endpoint was the mean di…
Dynamics of tumor oxygenation and red blood cell flux in response to inspiratory hyperoxia combined with different levels of inspiratory hypercapnia.
2002
Abstract Background and purpose : Increasing arterial oxygen partial pressure (pO 2 ) by breathing hyperoxic gases is an effective means of improving tumor oxygenation, although the efficacy of adding CO 2 to the inspiratory gas has been discussed controversially. This study aimed at analyzing the impact of different inspiratory CO 2 fractions on the time course of oxygenation and perfusion changes in experimental tumors during and after inspiratory hyperoxia. Material and methods : Perfusion and oxygenation of rat DS-sarcomas were studied during spontaneous breathing of pure oxygen or hyperoxic gas mixtures containing different CO 2 fractions (1, 2.5 or 5%). Red blood cell (RBC) flux was a…
Numerical simulation of glottal flow
2012
In cases of permanent immobility of both vocal folds patients have difficulties with breathing but rarely with voicing. However, clinical experience shows that the shape of the larynx (voice box) seems to have a significant influence on the degree of airflow and breathing pattern. In order to find an optimal geometry of the larynx in terms of easiness for breathing after the surgical change of vocal folds or false vocal cords (ventricular folds), a set of numerical simulations of glottal flow for weakly compressible Navier-Stokes equations has been performed. We compare airflow resistance and volumetric flow rate for several geometry concepts for inspiration as well as expiration. Finally, …
Influence of intravenously administered lidocaine on cerebral blood flow in a baboon model standardized under controlled general anaesthesia using si…
1993
The baboon under general anaesthesia as a model to assess drug-induced cerebral blood flow changes (delta CBF) using single-photon emission tomography (SPET) offers great in vivo possibilities but has to comply with demands on control of anaesthesia-related influencing factors, such as PaCO2 changes. The model sought in this study and described here allows control of PaCO2, in the baboon under thiopentone anaesthesia by ventilation, and was evaluated for the functional dependence of delta CBF vs delta PaCO2, using SPET technetium-99m hexamethylpropylene amine oxime (HMPAO) and the split-dose method together with controlled ventilation. During the experiment the model was validated for norma…
Protective intraoperative ventilation with higher versus lower levels of positive end-expiratory pressure in obese patients (PROBESE): study protocol…
2017
Background Postoperative pulmonary complications (PPCs) increase the morbidity and mortality of surgery in obese patients. High levels of positive end-expiratory pressure (PEEP) with lung recruitment maneuvers may improve intraoperative respiratory function, but they can also compromise hemodynamics, and the effects on PPCs are uncertain. We hypothesized that intraoperative mechanical ventilation using high PEEP with periodic recruitment maneuvers, as compared with low PEEP without recruitment maneuvers, prevents PPCs in obese patients. Methods/design The PRotective Ventilation with Higher versus Lower PEEP during General Anesthesia for Surgery in OBESE Patients (PROBESE) study is a multice…
A model of stepwise isovolaemic blood exchange in anaesthetised, spontaneously breathing rats to evaluate the oxygen transport efficiency of artifici…
2000
Our research pursues the production of hypo-oncotic artificial oxygen carriers, based on artificial covalently cross-linked hyperpolymeric mammalian haemoglobins. To evaluate their in vivo efficiency in oxygen delivery to the tissue we developed a small animal model of stepwise isovolaemic blood exchange in anaesthetised, spontaneously breathing rats. With the aid of a two-way respiratory micro valve for small animals the overall oxygen uptake by the tissue of the animal can be determined. Measurements of oxygen contents in arterial and mixed venous blood and of some further blood parameters together with known oxygen-binding characteristics of artificial and native oxygen carriers, permits…