Respiratory System Practice

The first bedside question is not “What is the diagnosis?” It is “Can this patient move air and maintain oxygenation?” An experienced nurse watches the patient before focusing on the monitor. A person who is upright and bracing the arms, using accessory muscles, speaking only a few words at a time, or becoming drowsy is spending increasing effort on breathing. Cyanosis, altered level of consciousness, exhaustion, and inability to speak in full sentences indicate a failing respiratory system rather than uncomplicated dyspnoea. Oxygenation and ventilation are different problems. Oxygen saturation estimates how much haemoglobin carries oxygen; it does not reveal whether carbon dioxide is accumulating. A patient receiving supplemental oxygen may have an acceptable SpO₂ while developing hypercapnia. Ventilation is better reflected by the PaCO₂, respiratory pattern, mental status, and—when available—capnography. A silent chest is an ominous finding in severe asthma: airflow may be so limited that little wheezing is produced. Likewise, a respiratory rate that falls in a previously tachypnoeic, distressed patient can signal fatigue and impending respiratory failure. Escalate immediately for absent air entry, cyanosis, altered consciousness, rising...