@rtwademethod: PaCO₂ and ETCO₂ are related, but they are not interchangeable. When alveoli are ventilated but poorly perfused, dead-space ventilation increases. Less CO₂ reaches those alveoli, so the exhaled ETCO₂ can decrease even while arterial CO₂ remains elevated. That produces a widening PaCO₂–ETCO₂ gradient. Pulmonary embolism is one possible cause, but so are low cardiac output, severe lung disease and other conditions that create ventilation-perfusion mismatch. The capnogram is a clue—not a stand-alone diagnosis. Always compare the trend with the patient’s ABG, hemodynamics, minute ventilation and overall clinical condition. #RespiratoryTherapy #criticalcare #rtstudent #capnography #icu

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Wednesday 09 September 2026 01:00:00 GMT