V. Hoffstein

Airflow Limitation in Morbidly Obese, Nonsmoking Men

STUDY OBJECTIVEnTo determine the effect of obesity on pulmonary function.nnnDESIGNnCase-control study, using nonobese, age- and height-matched [corrected] nonsmokers.nnnSETTINGnMetabolic and obesity clinics of two major teaching hospitals.nnnPATIENTSnOne hundred and three obese, lifelong nonsmokers without cardiopulmonary disease.nnnCONTROLSnOne hundred and ninety healthy, nonobese nonsmokers recruited from among hospital personnel.nnnMEASUREMENTS AND MAIN RESULTSnComplete pulmonary function measurements in all patients and controls. These measurements included maximum expiratory flow-volume curve, lung volumes and airway resistance using body plethysmograph, single-breath diffusing capacity for carbon monoxide, and total lung capacity using the helium dilution technique. Obese persons were found to have lower functional residual capacity, expiratory reserve volume, and total lung capacity by helium dilution than nonobese controls. In addition, residual volume and diffusing capacity were higher in the obese group. Finally, we found that obese men, but not women, had reduced maximum expiratory flow rates at 50% and 75% of exhaled vital capacity.nnnCONCLUSIONnObesity may contribute independently of smoking habits to chronic airflow limitation in men.

Acoustic rhinometry in the evaluation of nasal obstruction.

Acoustic rhinometry (AR) is a recently developed objective technique for assessment of geometry of the nasal cavity. The technique is based on the analysis of sound waves reflected from the nasal cavities. It measures cross‐sectional areas and nasal volume (NV). To obtain dependable assessments of nasal resistance by rhinomanometry or cross‐sectional area measurements by AR, it is essential that the structural relations of the compliant vestibular region remain undisturbed by the measuring apparatus. The use of nozzles in making these measurements carries a great risk of direct distortion of the nasal valve. We used a nasal adapter that does not invade the nasal cavity and a chin support that stabilizes the head. In 51 healthy nasal cavities, the average minimum cross‐sectional area (MCA) was 0.62 cm2 at 2.35 cm from the nostril and 0.67 cm2 at 2 cm from the nostril, respectively, before and after topical decongestion of the nasal mucosa. The MCA and NV findings in this group were significantly higher than MCA and NV (P<0.001) in people with structural or mucosal abnormalities before mucosal decongestion. After mucosal decongestion, the MCA and NV were significantly higher in healthy nasal cavities than in nasal cavities with structural abnormalities (P<0.001) but were not higher than nasal cavities with mucosal abnormalities (MCA, P = 0.05; NV, P = 0.06). A nozzle was applied in 20 healthy nasal cavities after mucosal decongestion, and a significantly higher MCA was found compared to measurements made with the nasal adapter (P = 0.02). We conclude that the nasal adapter, which does not invade the nasal cavities, avoids the distortion of the nasal valve and gives more accurate results.

Sleep apnea and systemic hypertension: A causal association review

OBJECTIVEnTo critically examine the causal association between sleep apnea syndrome and hypertension.nnnMETHODSnA retrospective systematic critique of five epidemiologic studies published in the English literature during 1978 to 1989 identified on Medline and manual literature searches. The evidence was evaluated using the standard observational criteria for causation: strength of association, consistency, dose-response relationship, temporal sequence, specificity, and biologic plausibility.nnnRESULTSnWe found evidence to support a causal association between sleep apnea syndrome and hypertension in consistency and specificity and some evidence to suggest a dose-response relationship. Review of the data dealing with the mechanisms important in the pathogenesis of sleep apnea and hypertension allowed us to advance several theories to provide support for biologic plausibility.nnnCONCLUSIONnWe concluded that there is a positive association--relative risk estimate between 1.3 and 40--for sleep apnea syndrome and hypertension, but the risk association is unstable. Thus, we believe that there is insufficient data to justify doing polysomnography as part of the routine diagnostic work-up for patients with hypertension.

Determinants of blood pressure in snorers

To examine the hypothesis that the tendency to raised blood pressure in snorers is associated with nocturnal hypoxaemia and snoring, blood pressure was measured and snoring, oxyhaemoglobin saturation (SaO2), and thoraco-abdominal movements were monitored overnight in 372 snorers. Snoring was quantified as number of snores per hour of sleep (snoring index). The data were analysed by multiple linear regression of diastolic blood pressure against age, body mass index (BMI), apnoea-hypopnoea index (AHI, number of episodes per hour), snoring index, and SaO2. Diastolic blood pressure correlated significantly with BMI, AHI, and mean nocturnal oxygen saturation, but not with the snoring index. However, snoring index correlated with BMI, AHI, and mean nocturnal oxygen saturation. Snoring is thus not a direct risk factor for hypertension, but may influence blood pressure via its association with obesity, obstructive sleep apnoea, and nocturnal hypoxaemia.

Paradoxical glottic narrowing in patients with severe obstructive sleep apnea.

Most patients with obstructive sleep apnea have increased pharyngeal collapsibility (defined in the present study as an increased lung volume dependence of pharyngeal area), which predisposes them to upper airway occlusion during sleep. However, there are patients with severe obstructive sleep apnea who have low-normal pharyngeal collapsibility. The factors leading to nocturnal upper airway obstruction in such patients have not been ascertained. We studied 10 overweight male patients with severe obstructive sleep apnea and low-normal pharyngeal collapsibility to determine the site of upper airway pathology in these patients. We found that all 10 patients exhibited paradoxical inspiratory narrowing of the glottis during quiet tidal breathing. This phenomenon was not observed in a matched group of 10 snoring, nonapneic male controls. We conclude that paradoxical glottic narrowing may be a contributing factor in the pathogenesis of upper airway obstruction in patients with severe obstructive sleep apnea who have low-normal pharyngeal collapsibility.

Search for chronic beryllium disease among sarcoidosis patients in Ontario, Canada.

Chronic beryllium disease (CBD) is clinically similar to other granulomatous diseases such as sarcoidosis. It is often misdiagnosed if a thorough occupational history is not taken. When appropriate, a beryllium lymphocyte proliferation tests (BeLPT) need to be performed. We aimed to search for CBD among currently diagnosed pulmonary sarcoidosis patients and to identify the occupations and exposures in Ontario leading to CBD. Questionnaire items included work history and details of possible exposure to beryllium. Participants who provided a history of previous work with metals underwent BeLPTs and an ELISPOT on the basis of having a higher pretest probability of CBD. Among 121 sarcoid patients enrolled, 87 (72%) reported no known previous metal dust or fume exposure, while 34 (28%) had metal exposure, including 17 (14%) with beryllium exposure at work or home. However, none of these 34 who underwent testing had positive test results. Self-reported exposure to beryllium or metals was relatively common in these patients with clinical sarcoidosis, but CBD was not confirmed using blood assays in this population.

Sarcoidosis–lymphoma syndrome: a diagnostic dilemma

Sarcoidosis and lymphoma are generally thought of as being two mutually exclusive diseases that need to be considered in the differential diagnosis of patients with hilar/mediastianal lymphadenopathy. However, there are rare patients in whom both of these diseases coexist. These patients constitute a diagnostic challenge because their presentation (ie, clinical symptoms, imaging abnormalities and even pathology) may all be atypical when each individual disease is considered separately. In this report, we describe a patient who presented with such atypical features and was eventually diagnosed as having both sarcoidosis and a B-cell lymphoma with features of splenic marginal zone lymphoma (SMZL) simultaneously. To our knowledge, this is only the second reported case of SMZL and sarcoidosis in the same patient.