Search results for "Tidal Volume"
showing 10 items of 75 documents
Impact of gas emboli and hyperbaric treatment on respiratory function of loggerhead sea turtles (Caretta caretta)
2018
We investigated lung function in bycaught sea turtles with and without gas emboli. Hyperbaric O2 treatment significantly improves lung function. Pulmonary function testing may be a useful diagnostic tool to assess fisheries induced trauma.
Ventilation and gas exchange before and after voluntary static surface breath-holds in clinically healthy bottlenose dolphins, Tursiops truncatus
2019
ABSTRACT We measured respiratory flow ( V ), breathing frequency ( f R ), tidal volume ( V T ), breath duration and end-expired O 2 content in bottlenose dolphins ( Tursiops truncatus ) before and after static surface breath-holds ranging from 34 to 292 s. There was considerable variation in the end-expired O 2 , V T and f R following a breath-hold. The analysis suggests that the dolphins attempt to minimize recovery following a dive by altering V T and f R to rapidly replenish the O 2 stores. For the first breath following a surface breath-hold, the end-expired O 2 decreased with dive duration, while V T and f R increased. Throughout the recovery period, end-expired O 2 increased while the…
Lung function assessment in the Pacific walrus (Odobenus rosmarus divergens) while resting on land and submerged in water
2020
In the present study, we examined lung function in healthy resting adult (born in 2003) Pacific walruses (Odobenus rosmarus divergens) by measuring respiratory flow ([Formula: see text]) using a custom-made pneumotachometer. Three female walruses (670-1025 kg) voluntarily participated in spirometry trials while spontaneously breathing on land (sitting and lying down in sternal recumbency) and floating in water. While sitting, two walruses performed active respiratory efforts, and one animal participated in lung compliance measurements. For spontaneous breaths, [Formula: see text] was lower when walruses were lying down (e.g. expiration: 7.1±1.2 l s-1) as compared with in water (9.9±1.4 l s-…
Expression of aquaporins 1 and 5 in a model of ventilator-induced lung injury and its relation to tidal volume
2016
New Findings What is the central question of this study? Although different studies have attempted to find factors that influence the expression of aquaporins (AQPs) in the lung in different situations, to date no research group has explored the expression of AQP1 and AQP5 jointly in rats mechanically ventilated with different tidal volumes in a model of ventilator-induced lung injury. What is the main finding? Mechanical ventilation with a high tidal volume causes lung injury and oedema, increasing lung permeability. In rats ventilated with a high tidal volume, the pulmonary expression of AQP1 decreases. We analysed the expression of aquaporins 1 and 5 and its relation with tidal volume in…
Do ventilatory parameters influence outcome in patients with severe acute respiratory infection? Secondary analysis of an international, multicentre1…
2021
Purpose: To investigate the possible association between ventilatory settings on the first day of invasive mechanical ventilation (IMV) and mortality in patients admitted to the intensive care unit (ICU) with severe acute respiratory infection (SARI). Materials and methods: In this pre-planned sub-study of a prospective, multicentre observational study, 441 patients with SARI who received controlled IMV during the ICU stay were included in the analysis. Results: ICU and hospital mortality rates were 23.1 and 28.1%, respectively. In multivariable analysis, tidal volume and respiratory rate on the first day of IMV were not associated with an increased risk of death; however, higher driving pr…
Humidity of Anaesthetic Gases with Respect to Low Flow Anaesthesia
1994
It has been demonstrated in an experimental study in swine using the scanning electron microscope that a rebreathing technique utilising minimal fresh gas flowrates significantly improves climatization of anaesthetic gases. Consequently, effects of various anaesthetic techniques on airway climate must be assessed, which covers the need for suitable measuring devices. Basic principles and methods of humidity measurement in flowing anaesthetic gases include gravimetric hygrometry, dew point hygrometry, wet-dry bulb psychrometry, mass spectrometry, spectroscopic hygrometry and electrical hygrometry. A custom-made apparatus for continuous measurement of humidity and temperature in the inspired…
Intraoperative positive end-expiratory pressure and postoperative pulmonary complications: a patient-level meta-analysis of three randomised clinical…
2022
BACKGROUND: High intraoperative PEEP with recruitment manoeuvres may improve perioperative outcomes. We re-examined this question by conducting a patient-level meta-analysis of three clinical trials in adult patients at increased risk for postoperative pulmonary complications who underwent non-cardiothoracic and non-neurological surgery. METHODS: The three trials enrolled patients at 128 hospitals in 24 countries from February 2011 to February 2018. All patients received volume-controlled ventilation with low tidal volume. Analyses were performed using one-stage, two-level, mixed modelling (site as a random effect; trial as a fixed effect). The primary outcome was a composite of postoperati…
Effect of Lung Recruitment and Titrated Positive End-Expiratory Pressure (PEEP) vs Low PEEP on Mortality in Patients With Acute Respiratory Distress …
2017
Importance The effects of recruitment maneuvers and positive end-expiratory pressure (PEEP) titration on clinical outcomes in patients with acute respiratory distress syndrome (ARDS) remain uncertain. Objective To determine if lung recruitment associated with PEEP titration according to the best respiratory-system compliance decreases 28-day mortality of patients with moderate to severe ARDS compared with a conventional low-PEEP strategy. Design, Setting, and Participants Multicenter, randomized trial conducted at 120 intensive care units (ICUs) from 9 countries from November 17, 2011, through April 25, 2017, enrolling adults with moderate to severe ARDS. Interventions An experimental strat…
Respiratory Mechanics, Gastric Insufflation Pressure, and Air Leakage of the Laryngeal Mask Airway
1997
A potential risk of the laryngeal mask airway (LMA) is incomplete mask seal, which causes air leakage or insufflation of air into the stomach. The objective of the present study was to assess respiratory mechanics, quantify air leakage, and measure gastric air insufflation in patients ventilated via the LMA. Thirty patients were studied after induction of anesthesia but prior to any surgical manipulations. After the insertion of the LMA, patients were ventilated with increasing tidal volumes until one of the three following end points were reached: 1) gastric air insufflation, 2) airway pressure > 40 cm H2O, or 3) limitation of further increase in tidal volume by air leakage. The following …
Tidal Volume Estimation during Helmet Noninvasive Ventilation: an Experimental Feasibility Study
2019
AbstractWe performed a bench (BS) and human (HS) study to test the hypothesis that estimation of tidal volume (VT) during noninvasive helmet pressure support ventilation (nHPSV) would be possible using a turbine driven ventilator (TDV) coupled with an intentional leak single-limb vented circuit. During the BS a mannequin was connected to a lung simulator (LS) and at different conditions of respiratory mechanics, positive end expiratory pressure (PEEP) levels and leaks (30, 50 and 80 L/min). All differences were within the 95% limits of agreement (LoA) in all conditions in the Bland-Altman plot. The overall bias (difference between VT measured by TDV and LS) was 35 ml (95% LoA 10 to 57 ml), …