The association of somatic arousal with the symptoms of upper airway resistance syndrome.

OBJECTIVES: We tested the hypothesis that the symptoms of upper airway resistance syndrome (UARS) are manifestations of chronic stress. To accomplish this, we utilized the score on a self-report questionnaire for somatic arousal (a component of stress) to compare somatic arousal between UARS patients and healthy controls and, among all participants, to correlate the level of somatic arousal with the severity of UARS symptoms. METHODS: We administered the Mood and Anxiety Symptom Questionnaire anxious arousal subscale (MASQaas; a 17-item questionnaire with increasing levels of arousal scored 17-85) to 12 UARS patients and 12 healthy controls and compared scores between groups. For all participants, we correlated the MASQaas scores with scores for the Epworth Sleepiness Scale (ESS), Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-Fatigue) scale, Pittsburgh Sleep Quality Index (PSQI), SF-36 Health Survey, and Perceived Deficits Questionnaire (PDQ; assessing cognitive function). RESULTS: Compared to healthy controls, UARS patients demonstrated increased somatic arousal (MASQaas scores of 18±2 and 28±7, respectively; p<0.0001). For all participants, the MASQaas scores correlated significantly with scores of the ESS (r=0.64; p=0.0008), the FACIT-Fatigue scale (r=-0.89; p<0.0001), the PSQI (r=0.70; p=0.0002), SF-36 Physical component (r=-0.78; p<0.0001), SF-36 Mental component (r=-0.74; p<0.0001), and the PDQ (r=0.89; p<0.0001). CONCLUSIONS: Our findings suggest that UARS patients have increased levels of the stress component, somatic arousal, proportionate to the severity of their symptoms.

A comparison of inspiratory airflow dynamics during sleep between upper airway resistance syndrome patients and healthy controls.

OBJECTIVES: A test of the hypothesis that upper airway resistance syndrome (UARS) patients have an increased prevalence of inspiratory airflow limitation (IFL) during sleep compared to healthy controls. METHODS: We compared inspiratory airflow dynamics during sleep between 12 UARS patients (nine females and three males) and 12 healthy controls matched for age, gender and obesity with maximal age limited at 45 years. A standard clinical polysomnogram (airflow measured with a nasal/oral pressure catheter) was performed to assess the impact of SDB on the participants' natural sleep. A second full-night polysomnogram with a pneumotachograph and a supraglottic pressure catheter to measure airflow and effort was performed to compare the maximal inspiratory airflow and effort and the percentage of flow-limited breaths during supine, continuous stage 2 sleep between groups. RESULTS: During clinical polysomnography, UARS participants did not differ significantly from controls in sleep architecture or fragmentation. We observed a small difference in apnea hypopnea index between UARS participants and controls (1.6 ± 1.9 vs. 0.4 ± 0.3, respectively; p = 0.035). During supine, continuous stage 2 sleep, 64.2 % (35.8; mean (SD)) of UARS participants' breaths were flow-limited compared with 34.0 % (39.3) of controls' breaths (p = 0.06). The groups did not differ in maximal inspiratory airflow or inspiratory effort. CONCLUSIONS: Our findings indicate a less-than-robust difference in respiratory parameters during sleep between UARS patients and healthy controls and no difference in standard sleep parameters or sleep fragmentation. We consider a pathophysiology of UARS that incorporates these findings.

The effects of a mid-day nap on the neurocognitive performance of first-year medical residents: a controlled interventional pilot study.

PURPOSE: Despite shorter duty hours, fatigue remains a problem among medical residents. The authors tested the effect of a short, mid-day nap on the cognitive functioning and alertness of first-year internal medicine (IM) residents during normal duty hours. METHOD: This was a controlled, interventional study performed between July 2008 and April 2010. The authors recruited a nap group of 18 residents and a rest (control) group of 11 residents. Investigators connected all participants to an ambulatory sleep monitor before the beginning of their shifts in order to monitor rolling eye movements, a proxy for attention failures. At mid-day, both groups took Conner's Continuous Performance Test (CPT II) to evaluate their cognitive functioning and then were placed in a reclining chair designed for napping. The authors instructed nap group residents to nap for up to 20 minutes and chatted with control group residents to prevent them from napping. All residents took the CPT II again immediately after the intervention. Residents' attention failures were recorded until the end of the workday. The authors compared the mean outcome parameters of the two groups through analysis of variance, using effect-of-treatment and baseline covariates. RESULTS: Nap group participants slept a mean of 8.4±3.0 minutes. Compared with controls whose cognitive functioning and number of attention failures did not change from morning to afternoon, the nap group's cognitive functioning improved and their number of attention failures decreased. CONCLUSIONS: A short, mid-day nap can improve cognitive functioning and alertness among first-year IM residents.

The effect of nasal continuous positive airway pressure on the symptoms of Gulf War illness.

PURPOSE: We performed a pilot study to determine whether nasal continuous positive airway pressure (CPAP) alleviates the symptoms of veterans with Gulf War illness (GWI) and sleep disordered breathing (SDB). METHODS: Eighteen male veterans with GWI and SDB recruited by advertisement, participated in a randomized, single-masked, sham-controlled treatment trial. Participants received 3 weeks of treatment during sleep with either therapeutic nasal CPAP or sham nasal CPAP. Using validated questionnaires, pain, fatigue, cognitive function, sleep disturbance, and general health were assessed by self-report before and after treatment. One of the participants assigned to therapeutic CPAP was excluded from the trial before starting treatment, leaving 17 participants. RESULTS: Compared to the nine sham nasal CPAP recipients, the eight participants receiving therapeutic nasal CPAP experienced improvements in pain (34%; p = 0.0008), fatigue (38%; p = 0.0002), cognitive function (33%; p = 0.004), sleep quality (41%; p = 0.0003), physical health (34%; p = 0.0003), and mental health (16%; p = 0.03). CONCLUSIONS: Our findings in this pilot study suggest that nasal CPAP may greatly improve symptoms in veterans with GWI and SDB.

Inspiratory airflow dynamics during sleep in veterans with Gulf War illness: a controlled study.

PURPOSE: To determine whether veterans with Gulf War Illness (GWI) are distinguished by sleep-disordered breathing, we compared inspiratory airflow dynamics during sleep between veterans with GWI and asymptomatic veterans of the first Gulf War. METHODS: We recruited 18 male veterans with GWI and 11 asymptomatic male veterans of the first Gulf War by advertisement. The two samples were matched for age and body mass index. Each participant underwent a first full-night polysomnogram (PSG) while sleeping supine using standard clinical monitoring of sleep and breathing. A second PSG was performed measuring airflow with a pneumotachograph in series with a nasal mask and respiratory effort with a supraglottic pressure (Psg) catheter to assess the presence of inspiratory airflow limitation during supine N2 sleep. We determined the prevalence of flow-limited breaths by sampling continuous N2 sleep and plotting inspiratory flow against Psg for each breath in the sample. We expressed the prevalence of flow-limited breaths as their percentage in the sample. RESULTS: Compared to controls, veterans with GWI had an increased frequency of arousals related to apneas, hypopneas, and mild inspiratory airflow limitation. During supine N2 sleep, veterans with GWI had 96 ± 5% (mean ± SD) of their breaths flow-limited while controls had 36 ± 25% of their breaths flow limited (p < 0.0001). CONCLUSIONS: Veterans with GWI experience sleep-disordered breathing that may distinguish them from asymptomatic veterans of the first Gulf War.

War-related illness symptoms among Operation Iraqi Freedom/ Operation Enduring Freedom returnees.

OBJECTIVE: Our objective was to determine the pattern of war-related illness (WRI) symptoms among returnees of Operation Iraqi Freedom/Operation Enduring Freedom (OIF/OEF) living on Long Island, NY. METHODS: We conducted an anonymous mail survey of WRI symptoms of a random cohort of 786 returnees (718 male, 68 female) living on Long Island from among 5,500 who registered with the OIF/OEF Registry. RESULTS: From among the 786 returnees whom we surveyed, we subsequently excluded 111 whose surveys were either returned unopened or who changed address. Two hundred seventy-four of the remaining 675 returnees responded to the survey (a 41% response rate). Disabling WRI symptoms were documented in approximately 2/3 of the responders and 75% of these responders had two or more symptoms. CONCLUSION: War-related illness symptoms are very common among OIF/OEF returnees suggesting the need for management strategies targeting their symptoms. BACKGROUND: Military conflicts have produced war-related illness (WRI) among our troops and veterans since the Civil War. Common to all these WRIs are a group of symptoms including body pain, fatigue, headache, sleep disturbance, diarrhea, forgetfulness, and impaired concentration. Also common to them is the absence of a discernable pathophysiology. Because WRI is poorly understood, we cannot prevent new occurrences with each new engagement of our armed forces.

Inspiratory airflow dynamics during sleep in irritable bowel syndrome: a pilot study.

PURPOSE: This study is a preliminary test of the hypothesis that the pathophysiology of irritable bowel syndrome (IBS) derives from pharyngeal collapse during sleep. MATERIALS AND METHODS: We studied inspiratory airflow dynamics during sleep in 12 lean females with IBS and 12 healthy female controls matched for age and obesity. A standard clinical polysomnogram (airflow measured with a nasal/oral pressure catheter) was performed to assess the impact of pharyngeal collapse on the participants' natural sleep. A second polysomnogram with a pneumotachograph and a supraglottic pressure catheter to measure airflow and effort was performed to compare the maximal inspiratory airflow and effort and the prevalence of inspiratory airflow limitation (IFL) during supine stage 2 sleep between groups. RESULTS: During clinical polysomnography, IBS participants did not differ significantly from controls in sleep architecture or respiration. The difference in apnea-hypopnea index between IBS participants and controls, however, approached statistical significance (2.8 +/- 2.7 vs 1.1 +/- 1.5, respectively; p = 0.079). Although nine of the 12 IBS participants had a prevalence of IFL of at least 33% during supine stage 2 sleep, they did not differ from controls in maximal inspiratory airflow, inspiratory effort, or the prevalence of IFL. Controls, however, differed from IBS participants in having their prevalence of IFL during stage 2 sleep positively correlated with age (r = 0.86; p = 0.0003) while IBS participants demonstrated no relationship between the prevalence of IFL and age. CONCLUSIONS: Our findings, while less than definitive, suggest a prevalence pattern of pharyngeal collapse during sleep among females with IBS that differs from that of healthy females, providing necessary background to inform further work on the relationship of pharyngeal collapse during sleep to IBS.

Hypersomnolence, insomnia and the pathophysiology of upper airway resistance syndrome.

OBJECTIVE: In order to test the hypothesis that upper airway resistance syndrome (UARS) is merely an extension of the pathophysiology of obstructive sleep apnea/hypopnea (OSA/H) to less severe pharyngeal collapse during sleep, we compared the severity of hypersomnolence and the prevalence of insomnia in UARS patients to the patterns observed for OSA/H patients. Our goal was to determine whether the severity of hypersomnolence and the prevalence of insomnia observed in UARS patients could have been predicted from the patterns observed among OSA/H patients. METHODS: We performed a retrospective study of a large consecutive patient series evaluated at an academic sleep disorders center, including 220 OSA/H patients and 137 UARS patients. Patients had no other sleep-related diagnosis and underwent an initial evaluation that included a measure of hypersomnolence [a multiple sleep latency test (MSLT); 95%] or insomnia questionnaire (87%). Patients were characterized by anthropometric data, polysomnographic descriptive measures of sleep, MSLT data and insomnia questionnaire data. RESULTS: Severity of hypersomnolence decreased over the continuum from severe to mild OSA/H. A model fit to the OSA/H patients to predict severity of hypersomnolence significantly underestimated hypersomnolence in UARS patients, which was comparable in severity to that of patients with mild OSA/H. The frequency of sleep-onset insomnia increased over the continuum from severe to mild OSA/H and increased further in UARS. CONCLUSIONS: UARS is, in some respects, an extension of OSA/H to less severe pharyngeal collapse, but this does not adequately account for the symptom profile of patients with UARS. A physical model is proposed to account for the excess somnolence in UARS relative to expectations and the increasing frequency of sleep-onset insomnia along the continuum from severe OSA/H to UARS.

Influence of the antibiotic erythromycin on anaerobic treatment of a pharmaceutical wastewater.

A laboratory-scale anaerobic sequencing batch reactor was used to treat a model substrate mixture representing pharmaceutical wastewater at an organic loading rate of 2.9 g COD/(L d). After reaching stable operation the reactor was first exposed to low (1 mg/L) and, subsequently, to high (200 mg/L) concentrations of the antibiotic erythromycin. The addition of low levels of erythromycin resulted in a significant but limited reduction of biogas production by 5% and the higher level of erythromycin did not impact biogas production further, suggesting that a substantial fraction of the microbial populations in the ASBR were resistant to the antibiotic. Effluent soluble COD could not be accounted for in measured volatile fatty acids, perhaps suggesting the production of soluble microbial products. In batch tests evaluating the specific methanogenic activity, conversion of the model substrate mixture was only slightly affected by the presence of erythromycin. However, the conversion of butyric acid was inhibited when erythromycin was present. After 47 days of exposure to erythromycin, the conversion of butyric acid was inhibited to a lesser extent, suggesting the development of antibiotic resistance in the biomass. Exposure to antibiotics can affect specific substrate degradation pathways, leading to the accumulation of volatile fatty acids, soluble microbial products, and potentially to overall system instabilities.

Aerosol delivery and modern mechanical ventilation: in vitro/in vivo evaluation.

Aerosol delivery via a mechanical ventilator remains unregulated with no standards for drug delivery to intubated patients. Bench models predicting drug delivery have not been validated in vivo. For modern ventilator designs, we chose to identify, on the bench, the most important variables affecting aerosol delivery and to correlate in vitro predictions of aerosol delivery with in vivo end points independent of patient response. Test aerosols of albuterol and antibiotics were compared. Bench measurements of inhaled mass (percentage of nebulizer charge, mean +/- SEM) ranged from 5.7 +/- 0.5% to 37.4 +/- 1.6%, with breath-actuated nebulization and humidity identified as the most important factors determining aerosol delivery. In patients, sputum levels of deposited antibiotics varied from 1.10 to 19.6 microg/ml/mg. Variation in sputum levels correlated with predictions from the in vitro model. Aerosol delivery in ventilated patients can be efficient and reproducible only if defined ventilator parameters are tightly controlled. Key parameters can be determined via in vitro bench testing defining delivery standards for clinical trials of drugs with narrow therapeutic/toxicity ratios.