We believe that pulmonologists should expand the scope of their practice. In view of this, it was with great interest that we read the most recent review article on extraesophageal manifestations of gastroesophageal reflux disease (GERD), which was authored by gastroenterologists and pulmonologists.(1) The article is well written and is very clear.
Nevertheless, it caught our attention that obstructive sleep apnea, an extremely prevalent pathology that is strongly associated with GERD, was practically forgotten. In order to support our observation, we conducted a survey of how many articles on the association between GERD and the pathologies highlighted in the review are cited in the Medline database.
The first GERD-related pathology mentioned in the review article is asthma, and it is not by chance that it is also the most quoted association on Medline (791 articles). The second item was cough (510 Medline articles), followed by pulmonary fibrosis (35 articles) and laryngitis (209 articles). Other diseases highlighted in the aforementioned review (Table 1) were atelectasis (30 Medline articles), chronic bronchitis (40 articles), bronchiectasis (45 articles), chronic obstructive pulmonary disease (41 articles) and pneumonia (499 articles). Obstructive sleep apnea (59 Medline articles) was mentioned in the introduction of the review, alongside dental erosion (100 articles). The fact that the authors did not develop the topic of dental erosion is justified, since, despite being an apparently important topic (judging by the number of citations at MEDLINE), the review was not directed towards odontology. It was dismaying that obstructive sleep apnea syndrome, which falls under the purview of the field of pulmonology, was given the same importance as dental erosion, i.e., none. What should not be overlooked is the fact that we, the undersigned, are pulmonologists who are actively involved in the field of sleep. Therefore, our view might be distorted. We do not believe this to be the case.

Obstructive sleep apnea syndrome (OSAS) is a public health problem that affects at least 2% to 4% of the general population.(2) The numbers are even more dramatic when we consider that OSAS is associated with various characteristics or diseases commonly seen in office visits, such as obesity, diabetes and systemic arterial hypertension. A study demonstrated that, among patients evaluated at a primary care clinic, over a third presented a high risk for OSAS.(3) Therefore, there is no doubt that, despite not being well recognized, OSAS is common. We also know that, when left untreated, OSAS is associated with significant worsening of quality of life, as well as with increased mortality from cardiovascular disease.(4) However, what is the relationship between OSAS and GERD?
To what do some of these 59 articles found on Medline refer?
Sleep, with or without OSAS, is associated with an increased risk of GERD. This is due to a series of physiological characteristics of sleep, including decreased peristalsis, reduced saliva production and a reduction in esophageal acid clearance. The risk of GERD increases dramatically in patients with OSAS. During obstructive respiratory events, the patient generates great negative intrathoracic pressure, which creates suction, resulting in backward flow of the gastric contents into the esophagus. The great respiratory effort against the occluded airway exerts a significant pressure in the phrenoesophageal ligament, which is in turn connected to the lower esophageal sphincter. The repetition of the respiratory efforts results in cardiac insufficiency, creating a scenario that is even more propitious for reflux. Over one-third of all patients with OSAS present GERD, and the nasal continuous positive airway pressure procedure used to treat OSAS can also reduce GERD symptoms.(6)

Our letter is not specifically addressed to the authors of this meticulous review article, which simply gave little emphasis to the correlation between GERD and OSAS. We believe this lack of attention to OSAS might be the rule, rather than the exception. During the recent Update Course in Rio de Janeiro, sponsored by the Brazilian Society of Pulmonology and Phthisiology, we (the authors of this letter) met to discuss this troubling scenario, a state of genuine lethargy: pulmonologist drowsiness, and why not of the gastroenterologists as well, regarding sleep. The gastroenterologists should be spared, since they do not work directly in the field of sleep. The situation is much more serious for us, pulmonologists, for whom sleep is within our area of expertise. Therefore, we would like to launch the 'PULMONOLOGISTS, AWAKE!' campaign. We know of no other disease that is so common, is of such importance, can be treated with such efficacy, provides so many possibilities for intervention by pulmonologists and is yet so overlooked. In addition, we have seen an increase in the number of residents who abandon the field of Pulmonology. Openings in our specialty have been increasingly less sought after. Perhaps these young professionals have the perception that there are limited prospects in the labor market for pulmonologists or that the market is saturated. Therefore, dear colleagues, join us in our campaign: PULMONOLOGISTS, AWAKE!

REFERENCES

1. Gurkis RR, Rosa, ARP, Valle E, Borba MA, Valiati AA. Manifestações extra-esofágicas da doença do refluxo gastroesofágico. J Bras Pneumol. 2006;32(2)150-6.
2. Young T, Palta M, Dempsey J, Skatrud J, Weber S, Badr S. The occurrence of sleep-disordered breathing among middle-aged adults. N Engl J Med. 1993 Apr 29;328(17):1230-5.
3. Netzer NC, Stoohs RA, Netzer CM, Clark K, Strohl KP. Using the Berlin Questionnaire to identify patients at risk for the sleep apnea syndrome. Ann Intern Med. 1999;131(7):485-91.
4. Marin JM, Carrizo SJ, Vicente E, Agusti AG. Long-term cardiovascular outcomes in men with obstructive sleep apnoea-hypopnoea with or without treatment with continuous positive airway pressure: an observational study. Lancet. 2005 Mar 19-25;365(9464):1046-53.
5. Morse CA, Quan SF, Mays MZ, Green C, Stephen G, Fass R. Is there a relationship between obstructive sleep apnea and gastroesophageal reflux disease? Clin Gastroenterol Hepatol. 2004;2(9):761-8.
6. Kerr P, Shoenut JP, Millar T, Buckle P, Kryger MH. Nasal CPAP reduces gastroesophageal reflux in obstructive sleep apnea syndrome. Chest. 1992;101(6):1539-44.