Ear, Nose and Throat (otorhinolaryngological) problems may be associated with extra-oesophageal reflux. (See the chapter on Reflux to explain the mechanism.) Pulmonary aspiration can take refluxate from the gastroinestinal tract into the lungs.
A correlation between cases of asthma and acid reflux has often been observed. "Upper abdominal symptoms, as well as symptoms suggesting rhinitis, were well correlated with asthma symptoms." [o-i]
From a report in Respirology March 2014: "The persistence of chronic cough over time should alert physicians to the possible involvement of GER." and "Until recently, pH-metry was accepted as the gold standard for establishing GER as the cause of respiratory symptoms. But it has now been rendered obsolete by studies ... that confirmed the role of nonacid reflux in patients with chronic cough." [o-ii] putting into question the prescribing of acid suppressant medication to relieve reflux related respiratory symptoms. "Remedial gastric surgery [is] indicated to control severe GER since fundoplication eliminates reflux of any kind."
Though some still advocate that acid suppression may alleviate these symptoms: "Gastro-esophageal reﬂux disease (GERD) regularly occurs when stomach acid moves up from the stomach into the esophagus. GERD might be associated with chronic asthma symptoms such as coughing and breathlessness. According to several studies on children and adults, GERD is proven to have a close relationship with asthma. Medication treatment via proton-pump inhibitors (PPIs), such as Omeprazole, H2 receptor blockers (Ranitidine), and other antireflux medications, is appropriate for ameliorating GERD and asthma. Moreover, surgery is another useful approach to GERD and asthma treatment. In this regard, Nissen fundoplication (laparoscopic) is a principal surgery method. Medical and surgical antireflux therapies are recognized as effective methods in the treatment of GERD-associated asthma. Our review included studies that evaluated treatment of GERD-associated asthma. These studies accentuated the critical role of acid reﬂux suppression in relieving the patients suffering from a difficult to control asthma." [o-iii]
Of course, respiratory symptoms may have various causes; reflux is just one of them.