A nasal cannula including a manifold having a delivery channel and a collection channel fluidly connected to a delivery nasal prong for delivering a gas to be inhaled from a patient's nose and to a collection prong for collecting gas exhaled from the patient's nose. The prongs are composed of a resilient material having sufficient memory that allows the prongs to be resiliently spread apart to be inserted into the respective nares of the patient's nose and when released, gently grasp the columella of the patient's nose to secure the cannula in position. The prongs are oriented leftwardly or rightwardly of the channels so that the right or left portions of the patient's face remain unobscured during surgery.