OA

• [o]esophageal atresia;

• obstructive apnea;

• occipital artery;

• occipito-anterior;

• occiput anterior;

• occupational asthma;

• octanoic acid;

• ocular albinism;

• old age;

• okadaic acid;

• oleic acid;

• on admission or arrival;

• open appendectomy;

• opiate analgesia;

• ophthalmic artery;

• opsonic activity;

• optic atrophy;

• oral airways;

• oral alimentation;

• organic anion;

• orotic acid;

• osteoarthritis;

• osteoarthrosis;

• ovalbumin;

• ovarian antibody;

• overall assessment;

• Overeaters Anonymous;

• oxalic acid