A carbon-dioxide sampling device for non-invasively measuring carbon dioxide in exhaled breath. The device includes a breath-sampling chamber and a carbon-dioxide collector. The breath-sampling chamber is configured to be disposed over a respiratory opening of a patient, and is also configured to seal with the patient's face preventing unintentional leakage of respiratory gases from the chamber. The carbon-dioxide collector is disposed in the breath-sampling chamber in fluid dynamic isolation from the respiratory gases. Moreover, the carbon-dioxide collector is configured to be disposed in proximity to, and outside of, the respiratory opening of the patient, and to collect a sample of exhaled breath from the patient.
