Nonhypersomnolent patients with obstructive sleep apnea.

Until recently, snoring had been considered both a medical enigma and a psychosocial problem. Snoring is now considered to be an acoustic phenomenon produced by vibration of the soft palate and the tonsillar pillars. We describe 20 patients with a clinical complaint of excessive snoring who were referred to rule out obstructive sleep apnea. All patients were without symptoms of daytime sleepiness and failure of the right heart. Twenty subjects were studied, 18 of whom were males. All subjects were monitored for one full night in the Sleep Laboratory. The apnea rate ranged from 9.0 to 94.0 incidents an hour with a mean of 30.0. Eight of the 20 subjects had obstructive episodes longer than 1 minute and three others had episodes longer than 55 seconds. Hypersomnolence, long thought to be a cardinal symptom, is not present in all patients with an ostensibly significant degree of obstructive sleep apnea.

Flow dependence of gas distribution and the pattern of inspiratory muscle contraction.

We measured regional distribution of xenon-133 boli at 0.25, 0.75, and 1.5 l/s in four normal seated subjects during inspirations performed predominantly with intercostal and accessory muscles (IC) or with the diaphragm, accompanied by outward abdominal motion (Ab). In six additional subjects we inferred the topographical distribution of helium boli during similar breaths and flow rates from the slope of the alveolar plateau recorded during a slow expiration (less than 0.5 l/s). Distribution of the helium boli was studied during natural as well as IC and Ab inspirations. At each of the flow rates IC breaths distributed relatively more of the inspired bolus to upper lung regions than did Ab inspirations. Natural breaths at 0.25 l/s resulted in distributions similar to those of Ab inspirations, whereas at 1.5 l/s the distribution approached that of IC inspirations. A three-compartment model, representing upper, middle, and lower lung regions, was used to simulate bolus distribution. The experimental data showed substantial departure from predictions based on regional time constants alone. However, additional small differences in applied pressure (less than 0.50 cmH2O) between the regions satisfactorily accounted for the gas distribution.

Prosthetic valve endocarditis: reviewing the problem.

Bacterial endocarditis is a serious complication of valve replacement, with an overall mortality of 59%. Fever, although a constant feature of the condition, is a nonspecific finding; other manifestations may or may not be present and the diagnosis may be overlooked. Any patient with a prosthetic heart valve and bacteremia should be considered to have endocarditis and should be treated accordingly.