Sleep apnea in 81 ambulatory male patients with stable heart failure. Types and their prevalences, consequences, and presentations.

BACKGROUND: Heart failure is a highly prevalent disorder that continues to be associated with repeated hospitalizations, high morbidity, and high mortality. Sleep-related breathing disorders with repetitive episodes of asphyxia may adversely affect heart function. The main aims of this study were to determine the prevalence, consequences, and differences in various sleep-related breathing disorders in ambulatory male patients with stable heart failure. METHODS AND RESULTS: This article reports the results of a prospective study of 81 of 92 eligible patients with heart failure and a left ventricular ejection fraction < 45%. There were 40 patients without (hourly rate of apnea/hypopnea, 4 +/- 4; group 1) and 41 patients with (51% of all patients; hourly rate of apnea/hypopnea, 44 +/- 19; group 2) sleep apnea. Sleep disruption and arterial oxyhemoglobin desaturation were significantly more severe and the prevalence of atrial fibrillation (22% versus 5%) and ventricular arrhythmias were greater in group 2 than in group 1. Forty percent of all patients had central sleep apnea, and 11% had obstructive sleep apnea. The latter patients had significantly greater mean body weight (112 +/- 30 versus 75 +/- 16 kg) and prevalence of habitual snoring (78% versus 28%). However, the hourly rate of episodes of apnea and hypopnea (36 +/- 10 versus 47 +/- 21), episodes of arousal (20 +/- 14 versus 23 +/- 11), and desaturation (lowest saturation, 72 +/- 11% versus 78 +/- 12%) were similar in patients with these different types of apnea. CONCLUSIONS: Fifty-one percent of male patients with stable heart failure suffer from sleep-related breathing disorders: 40% from central and 11% from obstructive sleep apnea. Both obstructive and central types of sleep apnea result in sleep disruption and arterial oxyhemoglobin desaturation. Patients with sleep apnea have a high prevalence of atrial fibrillation and ventricular arrhythmias.

Diagnostic strategies in Pneumocystis carinii pneumonia.

Pneumocystis carinii (P. carinii) remains a major pulmonary pathogen for the immunocompromised patient. In HIV infected patients, P. carinii represents the most commonly diagnosed cause of pneumonia. In the AIDS patient, empiric therapy based on clinical presentation has its proponents. However, this approach has been associated with a worse overall prognosis for the at risk patient. Because P. carinii can not be cultured, specific identification relies on examining respiratory specimens ranging from expectorated sputum to bronchoscopy with bronchoalveolar lavage (BAL). The low sensitivity of conventional stains has led to the search for antibodies to P. carinii and the use of immunofluorescent techniques. In addition, the polymerase chain reaction (PCR) is successfully being used in the diagnosis of P. carinii. Overall, these techniques allow the clinician to tailor the diagnostic testing for the individual patient.

Effect of theophylline on sleep-disordered breathing in heart failure.

BACKGROUND: Theophylline has been used to treat central apnea associated with Cheyne-Stokes respiration (periodic breathing). We studied the effect of short-term oral theophylline therapy on periodic breathing associated with stable heart failure due to systolic dysfunction. METHODS: Fifteen men with compensated heart failure (left ventricular ejection fraction, 45 percent or less) participated in the study. Their base-line polysomnograms showed periodic breathing, with more than 10 episodes of apnea and hypopnea per hour. In a double-blind crossover study, the patients received theophylline or placebo orally twice daily for five days, with one week of washout between the two periods. RESULTS: After five days of treatment, the mean (+/-SD) plasma theophylline concentration was 11 +/- 2 microgram per milliliter. Theophylline therapy resulted in significant decreases in the number of episodes of apnea and hypopnea per hour (18 +/- 17, vs. 37 +/- 23 with placebo and 47 +/- 21 at base line; P<0.001), the number of episodes of central apnea per hour (6 +/- 14, vs. 26 +/- 21 and 26 +/- 20, respectively; P<0.001), and the percentage of total sleep time during which the arterial oxyhemoglobin saturation was less than 90 percent (6 +/- 11 percent, vs., 23 +/- 37 and 14 +/- 14 percent, respectively; P<0.04). There were no significant differences in the characteristics of sleep, the frequency of ventricular arrhythmias, daytime arterial-blood gas values, or the left ventricular ejection fraction during the base-line, placebo, and theophylline phases of the study. CONCLUSIONS: In patients with stable heart failure, oral theophylline therapy reduced the number of episodes of apnea and hypopnea and the duration of arterial oxyhemoglobin desaturation during sleep.

Inhibition of hypochlorous acid by lidocaine and native components of alveolar epithelial lining fluid.

Alveolar epithelial lining fluid (ELF) contains several antioxidant substances that may provide in vivo protection. We studied the ability of ELF and ELF components to inhibit the neutrophil oxidant hypochlorous acid (HOCI). Normal bronchoalveolar lavage fluid containing ELF was incubated with physiologically relevant concentrations of HOCI (0.04 mM). After incubation, residual HOCI activity was titered by the iodide method. The inhibitory activity of lavage fluid was unexpectedly strong. For example, lavage fluid diluted 20-fold in the assay system quenched 49% of starting HOCI. We initially postulated that ELF total protein and glutathione would account for most of the inhibition of HOCI. However, several experimental approaches demonstrated that the total protein and glutathione concentrations in diluted lavage fluid were too low to explain the observed inhibition. Instead, the majority of HOCI inhibition was due to the lidocaine used for upper airway anesthesia. Reagent lidocaine exhibited strong reactivity in the HOCI assay system. Furthermore, the lavage fluid lidocaine concentration (32.4 +/- 6.9 micrograms/ml) was sufficient to explain most of the observed quenching activity. Additional experiments explored the hypothetical quenching activity of ELF components devoid of lidocaine. These findings demonstrate the technical problems posed by lidocaine in antioxidant studies involving lavage fluid or ELF.