Respiratory care
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Supplemental oxygen is designed to raise alveolar PO2 to facilitate diffusion into arterial blood. Oxygen is generally delivered by nasal cannula either by continuous or pulsatile flow. Battery-powered portable oxygen concentrators (POCs) facilitate ambulation in patients experiencing exertional hypoxemia. In the United States, the Food and Drug Administration (FDA) clears these devices to be sold by physician prescription. Recently, however, lower-cost devices described as POCs have been advertised by online retailers. These devices lack FDA clearance and are obtained over the counter (OTC) without prescription. This study determined whether a selected group of OTC POCs have oxygen delivery characteristics suitable for use by hypoxemic patients. ⋯ Only one of 3 OTC POCs tested was potentially of use by patients requiring ambulatory oxygen. Physicians and respiratory therapists should inform patients requiring portable oxygen that OTC devices may not meet their oxygenation requirements.
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Because ICU ventilators incorporate flow velocity measurement, cough peak expiratory flow (CPF) can be assessed without disconnecting the patient from the ICU ventilator. Our goal was to estimate the correlation between CPF obtained with the built-in ventilator flow meter (ventilator CPF) and CPF obtained with an electronic portable handheld peak flow meter connected to the endotracheal tube. ⋯ CPF measurements using a built-in ventilator flow meter were feasible in routine practice with cooperative ICU subjects who were intubated and correlated with CPF assessed by an electronic portable peak flow meter.
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Mechanical insufflation-exsufflation (MI-E) devices are used to improve airway clearance in individuals with acute respiratory failure. Some MI-E devices measure cough peak flow (CPF) during MI-E to optimize pressure adjustments. The aim was to compare CPF and effective cough volume (ECV: volume expired/coughed > 3 L/s) measurements between 4 MI-E devices under simulated conditions of stable versus collapsed airway. ⋯ CPF values differed significantly across MI-E devices, highlighting limitation(s) of using only CPF values to determine cough effectiveness. In simulated of airway collapse, CPF increased at the mouth, whereas it decreased at the tracheal level.