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Ventilation Strategy (ventilation + strategy)

Distribution by Scientific Domains

Medical Sciences	57%

Selected Abstracts

Effect of ventilation strategies on air contaminant concentrations and energy consumption in buildings

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 12 2001
Ismail M. Budaiwi
Abstract Considering the diversity of indoor contaminant characteristics and generation patterns, finding an appropriate ventilation strategy that can secure acceptable indoor air quality with minimum energy consumption is a challenging task for HVAC system designers and operators. This study theoretically models and investigates the impact of various ventilation strategies on contaminant concentration behaviour and corresponding ventilation cooling energy requirements for a single-zone enclosure. Two types of contaminants are considered; carbon dioxide as an occupancy dependent and formaldehyde, which is independent of occupancy. An airflow model is used to predict space pressure and air leakage rates across the enclosure envelope, and an air quality model is used to predict time-varying contaminant concentrations. In addition, a building energy simulation model is utilized to predict the corresponding ventilation cooling energy requirements under hot climatic conditions. Results from this study show that acceptable contaminant concentrations during occupied periods can be achieved by different ventilation strategies but at substantially different ventilation energy requirements. More than 50 per cent reduction in ventilation energy requirements can be obtained while maintaining acceptable IAQ if proper ventilation strategy is employed. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Successful use of short-term mechanical ventilation to manage respiratory failure secondary to profound hypokalemia in a cat with hyperaldosteronism

JOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 5 2008
Tara N. Hammond DVM
Abstract Objective , To report successful management of respiratory failure due to severe hypokalemia in a cat with hyperaldosteronism, including short-term mechanical ventilation strategies and aspects of medical and surgical treatment. Case Summary , A cat presented with bilateral pelvic limb weakness that rapidly progressed to tetraparesis and respiratory muscle failure. Point-of-care testing revealed severe hypokalemia (1.9 mmol/L) and mild azotemia. Initial management included endotracheal intubation, mechanical ventilation, and aggressive potassium supplementation. Spironolactone was started due to a high index of suspicion for hyperaldosteronism. A right adrenal mass visualized during abdominal ultrasonographic examination and a serum aldosterone level greater than 3329 pmol/L confirmed the diagnosis. The cat made a full recovery following surgical removal of a right adrenal adenoma. New or Unique Information Provided , We report successful management of respiratory failure in a cat with hyperaldosteronism using short-term mechanical ventilation. Respiratory failure due to severe hypokalemia should be considered a complication of hyperaldosteronism in cats and may require mechanical ventilation. However, full recovery is possible. [source]

How do COPD and healthy-lung patients tolerate the reduced volume ventilation strategy during OLV ventilation.

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 9 2010
P. MICHELET
Background: Although a strategy of tidal volume (Vt) reduction during the one-lung ventilation (OLV) period is advised in thoracic surgery, the influence of the pre-operative respiratory status on the tolerance of this strategy remains unknown. Therefore, the aim of this study was to compare the pulmonary function between chronic obstructive pulmonary disease (COPD) and healthy-lung patients during the operative and the post-operative period. Methods: Forty-eight patients undergoing a planned lobectomy for cancer and presenting either a healthy lung function (n=24) or a moderate COPD stage (n=24) were ventilated without external positive end-expiratory pressure (PEEP) and received 9 ml/kg Vt during the two-lung ventilation (TLV) period, secondary reduced to 6 ml/kg during the OLV period. Lung function was assessed by peroperative gas exchange, venous admixture, respiratory mechanical parameters and post-operative spirometric measurements. Results: Although the PaO2 was superior in the healthy-lung group during the TLV, once the OLV was established, no difference was observed between the two groups. Moreover, the PaO2/FiO2 was proportionally more impaired in the healthy-lung group compared with the COPD group (50 ± 13 vs. 72 ± 19% of the baseline values after exclusion and 32 ± 15 vs. 51 ± 25% after the thoracotomy, P<0.05 for each) as well as the venous admixture. In the post-operative period, a higher decrease was observed in the healthy-lung group for the forced vital capacity and the forced expiratory volume. Conclusions: Reducing Vt to 6 ml/kg without the adjunction of external PEEP during OLV is associated with better preservation of lung function in the case of moderate COPD than in the case of healthy-lung status. [source]

Effect of ventilation strategies on air contaminant concentrations and energy consumption in buildings

Protective ventilation to reduce inflammatory injury from one lung ventilation in a piglet model

PEDIATRIC ANESTHESIA, Issue 4 2010
MARY C. THEROUX MD
Summary Objectives:, To test the hypothesis that protective ventilation strategy (PVS) as defined by the use of low stretch ventilation (tidal volume of 5 ml·kg,1 and employing 5 cm of positive end expiratory pressure (PEEP) during one lung ventilation (OLV) in piglets would result in reduced injury compared to a control group of piglets who received the conventional ventilation (tidal volume of 10 ml·kg,1 and no PEEP). Background:, PVS has been found to be beneficial in adults to minimize injury from OLV. We designed the current study to test the beneficial effects of PVS in a piglet model of OLV. Methods:, Ten piglets each were assigned to either ,Control' group (tidal volume of 10 ml·kg,1 and no PEEP) or ,PVS' group (tidal volume of 5 ml·kg,1 during the OLV phase and PEEP of 5 cm of H2O throughout the study). Experiment consisted of 30 min of baseline ventilation, 3 h of OLV, and again 30 min of bilateral ventilation. Respiratory parameters and proinflammatory markers were measured as outcome. Results:, There was no difference in PaO2 between groups. PaCO2 (P < 0.01) and ventilatory rate (P < 0.01) were higher at 1.5 h OLV and at the end point in the PVS group. Peak inflating pressure (PIP) and pulmonary resistance were higher (P < 0.05) in the control group at 1.5 h OLV. tumor necrosis factor-alpha (P < 0.04) and IL-8 were less (P < 0.001) in the plasma from the PVS group, while IL-6 and IL-8 were less (P < 0.04) in the lung tissue from ventilated lungs in the PVS group. Conclusions:, Based on this model, PVS decreases inflammatory injury both systemically and in the lung tissue with no adverse effect on oxygenation, ventilation, or lung function. [source]

Benefits and risks of furosemide in acute kidney injury

ANAESTHESIA, Issue 3 2010
K. M. Ho
Summary Furosemide, a potent loop diuretic, is frequently used in different stages of acute kidney injury, but its clinical roles remain uncertain. This review summarises the pharmacology of furosemide, its potential uses and side effects, and the evidence of its efficacy. Furosemide is actively secreted by the proximal tubules into the urine before reaching its site of action at the ascending limb of loop of Henle. It is the urinary concentrations of furosemide that determine its diuretic effect. The severity of acute kidney injury has a significant effect on the diuretic response to furosemide; a good ,urinary response' may be considered as a ,proxy' for having some residual renal function. The current evidence does not suggest that furosemide can reduce mortality in patients with acute kidney injury. In patients with acute lung injury without haemodynamic instability, furosemide may be useful in achieving fluid balance to facilitate mechanical ventilation according to the lung-protective ventilation strategy. [source]