Resp Care
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Comparative Study
Comparison of measured versus predicted energy requirements in critically ill cancer patients.
Accurate determination of caloric requirements is essential to avoid feeding-associated complications in critically ill patients. ⋯ Underfeeding and overfeeding were common in our critically ill cancer patients when resting energy expenditure was estimated rather than measured. Indirect calorimetry is the method of choice for determining caloric need in critically ill cancer patients, but if indirect calorimetry is not available or feasible, the Harris-Benedict equation without added stress and activity factors is more accurate than the clinically estimated resting energy expenditure.
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The 2005 American Thoracic Society/European Respiratory Society guidelines on spirometry emphasize examination of the inspiratory curve of the flow-volume loop for evidence of intrathoracic or extrathoracic upper airway obstruction. We sought to determine how frequently evaluations are performed for abnormal inspiratory curves. ⋯ An abnormal inspiratory curve in the presence of otherwise normal spirometry should prompt an evaluation for the etiology. If one of the flow-volume inspiratory curves shows an abnormality, all the inspiratory curves from that PFT session should be reviewed, and if more than one inspiratory curves is abnormal, both anatomical and functional evaluation should be undertaken for intrathoracic and extrathoracic upper airway obstruction.
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Practitioners often presume there is adequate humidification in the ventilator circuit if the Y-piece is at a specified temperature, but control of Y-piece temperature may be inadequate to ensure adequate humidification. ⋯ Maintaining temperature at one point in the inspiratory circuit (eg, Y-piece), does not ensure adequate water-vapor delivery. Other factors (humidification system, V (E), gradient setting) are critical. At a given temperature, humidification may be significantly higher or lower than expected.
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Positive-expiratory-pressure (PEP) therapy uses positive airway pressure generated by a either a fixed-orifice resistor or a threshold resistor. We hypothesized that tubing diameter and length, and the diameter of the PEP bottle's air-escape orifice would impact the PEP pressure delivered to the airway and determine whether the PEP bottle acts as a threshold resistor or a fixed-orifice resistor. ⋯ To obtain a threshold-resistor PEP bottle system (ie, the PEP pressure is generated only by the water-column pressure), the tubing must be > or = 8 mm inner diameter, and the air-escape orifice must be > or = 8 mm.