Practice points
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Pulse oximetry, TCOMs and nasal cannula end-tidal CO2 devices are easy and reliable ways to monitor gas exchange
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Characteristic changes in pulmonary
Bearing in mind the diversity and prevalence of respiratory illnesses in children, paediatricians should understand the basics of respiratory physiology and how to monitor respiratory function. This discussion will review normal respiratory physiology and explore non-invasive forms of respiratory monitoring. With this foundation, the paediatrician can accurately diagnose and assess the severity of illness.
The most important and powerful muscle during the inspiratory phase of respiration is the diaphragm, a dome-shaped musculofibrous septum that separates the thorax from the abdominal cavity. When the diaphragm contracts, abdominal contents move downward and the lung expands in the vertical and horizontal planes. During normal tidal breathing the diaphragm moves approximately 1 cm, but with forced inspiration and exhalation, it can move up to 10 cm.
During inspiration, external intercostal muscles
The primary purpose of the respiratory system is gas exchange to maintain cellular homeostasis. The two principal components are delivery of oxygen and removal of carbon dioxide.
Cyanosis is the hallmark clinical sign of hypoxaemia, but it can only be recognized confidently when the oxygen saturation is below 75% and cannot be recognized if the haematocrit is less than 15%. Pulse oximetry allows for non-invasive and continuous monitoring of arterial oxygen saturation (SaO2). The basic principles of pulse oximetry are that oxygenated haemoglobin (HbO2) absorbs mostly infrared light while deoxygenated haemoglobin (Hb) absorbs mostly red light. Pulse oximeters exploit the
The primary pathological defect in obstructive airways disease is airflow limitation. This limitation can occur during expiration, inspiration or both. Both large airways obstruction (croup, epiglottitis, foreign-body aspiration, laryngomalacia, tracheomalacia) and medium (asthma) and small (bronchiolitis) airways obstruction have hallmark findings on physical examination and in the tests discussed above. Knowledge of these patterns assists the physician to localize the obstruction, determine
There is a wide array of non-invasive tools available to the paediatrician for diagnosis and management of various respiratory diseases. With a basic knowledge of respiratory physiology and how pathophysiological states can be monitored, the clinician can optimize therapeutic interventions and readily track disease progression. Pulse oximetry, TCOMs and nasal cannula end-tidal CO2 devices are easy and reliable ways to monitor gas exchange Characteristic changes in pulmonaryPractice points