What causes pulse oximeter readings to be inaccurate? The most common problem is the oximeter probe not consistently registering the pulsatile arterial flow through the skin. This is often caused by movement, poor perfusion of the skin, or bright ambient light. Careful attention to the graphical display of pulsatile flow on the pulse oximeter can …
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Pulse oximetry findings in respiratory failure in children Yes. Hypoxemia is not always obvious from the physical examination. Most children who are hypoxemic from a respiratory illness have signs of respiratory distress, but in many cases mild to moderate hypoxemia is clinically inapparent. Hypoxemia is a less potent stimulator of the respiratory center than is …
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Is wheezing a reliable sign of severe lower airway disease? No. Audible wheezing requires significant airflow through narrowed small airways. Children with severe obstruction of small airways may have so little airflow that audible wheezing is not present. These children usually have decreased inspiratory breath sounds and increased work of breathing. Administration of bronchodilators to …
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How to know if the respiratory failure is caused by an upper or lower airway disease? Distinguishing upper from lower respiratory disease is a difficult but important part of clinical evaluation. Many children have disease processes that involve the upper and lower respiratory tracts simultaneously, for example, bronchiolitis caused by respiratory syncytial virus. In general, …
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What are paradoxical respirations? Why do they occur? Infants who have increased airway resistance generate high negative intrathoracic pressures to inflate their lungs. As the diaphragm moves downward and the intrathoracic pressure becomes negative, the soft, cartilaginous bones and weak intercostal musculature cannot maintain the thoracic circumference. As the abdomen moves outward, the infant’s compliant …
What are retractions and why do they occur? Normally, inspiration is almost effortless. When airway resistance is high, a child must generate greater negative intrathoracic pressure to draw air into the lungs. That requires greater work of breathing, which can be seen as greater muscular activity of the neck, chest, and abdominal musculature. Flaring of …
Why does respiratory resistance increase so significantly with inflammation of the respiratory tree? The resistance to laminar airflow through a tube is inversely related to the radius of that tube taken to the fourth power (Poiseuille’s law). Modest decreases in the radius of the lumen of a small airway can lead to dramatic increases in …