Respiratory disturbance during sleep in COPD patients without daytime hypoxemia

Chronic obstructive pulmonary disease (COPD) is associated with significant morbidity and mortality. Its possible association with obstructive sleep apnea is a major cause of concern for clinicians. As the prevalence of both COPD and sleep apnea continues to rise, further investigation of this interaction is needed. In addition, COPD patients are at risk for hypoventilation during sleep due to the underlying respiratory dysfunction. In this study, 13 COPD subjects and 13 non-COPD control subjects were compared for the presence and severity of obstructive sleep apnea and nocturnal hypoventilation. All 26 subjects had presented to a sleep clinic and showed no signs of daytime hypoxemia. After matching for BMI and age, COPD subjects had a similar prevalence of sleep apnea with a lower degree of severity compared to the control subjects. However, less severe events, such as RERA, occurred at similar rates between the two groups. There was no significant difference between groups in the magnitude of oxyhemoglobin desaturation during sleep. Interestingly, severity and presence of nocturnal hypoxemia correlated with that of sleep apnea in the control group, but not in the COPD subjects. In conclusion, COPD without daytime hypoxemia was not a risk factor for sleep apnea or nocturnal hypoventilation in this study.     

Cognitive impairment in patients with obstructive sleep apnea and associated hypoxemia

Twenty-six patients with sleep apnea had neuropsychologic testing prior to nocturnal sleep study in a sleep disorders clinic. The cognitive functioning of patients who had sleep apnea with associated hypoxemia was compared to nonhypoxemic patients with sleep apnea. The patients who had sleep apnea with hypoxemia had more severe cognitive impairment than those with sleep apnea without hypoxemia. The hypoxemic patients with sleep apnea had significantly poorer cognitive functioning on four of eight tests (p less than 0.05). In addition, the patients who had sleep apnea with hypoxemia had mean performance scores in the impaired range on measures of attention, concentration, complex problem-solving, and short-term recall of verbal and spatial information. In contrast, the patients who had sleep apnea without hypoxemia had no mean performance score in the impaired range. The degree of hypoxemia during sleep and wakefulness significantly correlated with the degree of overall cognitive impairment as rated by a neuropsychologist; however, measures of sleep fragmentation did not significantly correlate with overall cognitive impairment in patients with sleep apnea. We conclude that patients who have sleep apnea with associated hypoxemia have cognitive impairment which is more severe than those with sleep apnea without hypoxemia.     

Familial dysautonomia: frequent, prolonged and severe hypoxemia during wakefulness and sleep

Sudden unexplained deaths have been reported in 13% [corrected] of Familial Dysautonomia (FD) subjects. To characterize cardiorespiratory dysregulation in children with FD that might contribute to potential sudden death, respiratory inductance plethysmography (chest/abdomen), ECG, hemoglobin saturation, and pulse waveform (VivoMetrics, Inc.) were recorded in the home during daytime wakefulness and overnight sleep in 25 children with IKBKAP mutation-confirmed FD and 25 age-, and gender-matched controls. Breath-to-breath and beat-to-beat characterization of breathing, hemoglobin saturation, and heart rate was conducted. Children with FD had more frequent, prolonged, and severe episodes of hypoxemia than matched controls, awake and asleep. Though a small percent of the study time revealed bradycardia and apnea, the hypoxemia was the most prevalent pattern in FD and rarely occurred with related bradycardia. Though infrequent with desaturation or bradycardia, apnea was more prevalent in FD subjects than controls, and more apparent during sleep than wakefulness. Children with FD have cardiorespiratory dysregulation during wakefulness and sleep, likely representing alveolar hypoventilation. We hypothesize that the related repeated hypoxemia (and presumed related hypercarbia) may render individuals with FD more vulnerable to sudden death.     

Opioid-associated central sleep apnea: a case series

Introduction  Subjects on methadone maintenance for drug addiction have been reported to have central sleep apnea (CSA). However, there are few reports of disordered breathing in patients receiving opioids for chronic pain. Materials and methods  We report on six patients (ages 41–68, two females, body mass index 27–34, morphine equivalent doses 120–420 mg/day, Epworth Scales 7–21) referred to our sleep center receiving sustained release opioids for more than 6 months with excessive daytime sleepiness. CSA was defined as apnea–hypopnea index (AHI) more than 5 per hour with ≥50% central events. Bilevel (BLV) titration was done to determine settings and all patients were followed for at least 6 months on nocturnal BLV. AHI ranged 28.4–106 per hour. Time less than 90% O₂ saturation ranged 1.8 min to 6.4 h. Four of the patients were treated with chronic BLV ventilation with settings ranging 12–16 cm H₂O (inspiratory positive airway pressure)/4–8 cm H₂O (expiratory positive airway pressure) with backup rate of 12–16. Among the four patients who used BLV treatment for at least 6 months, Epworth scores improved (by 4, 12, 5, and 9, respectively). Conclusion  Treatment of opioid-associated CSA with BLV corrected nocturnal hypoxemia and reduced sleep fragmentation. Randomized controlled trials, with objective measures of daytime function, are recommended in opioid-induced CSA patients.     

The development of a sleep apnea screening program in Romanian type 2 diabetic patients: a pilot study

To determine the feasibility of a sleep apnea screening program in Romanian patients with type 2 diabetes and obesity attending outpatient clinic of a diabetes center (the standard for routine care in Romania). The Epworth Sleepiness Scale was administered to 80 consecutive patients with type 2 diabetes and a body mass index (BMI) ≥30 kg/m2. Patients with a score >10 at this scale were referred to polysomnography for a sleep study. Overall, 20% of these patients had excessive daytime sleepiness (Epworth Sleepiness Scale >10), and in all of these cases, obstructive sleep apnea was confirmed. Of these patients, 33.3% had moderate OSA (AHI = 15–30 events/h of sleep), and 58.3% had severe OSA (AHI ≥30 events/h of sleep). Individuals with OSA were more frequent males, have higher BMI, higher waist circumference, and lower HDL-cholesterol compared with non-apneic subjects. Hb A1c, diabetes duration, and age were not statistically different between the two groups. OSA odds increased 1.1 times with every 1-cm increase in abdominal circumference (95%CI: 1.01–1.13) and 1.2 times with every kg/m2 increase in BMI (95%CI: 1.05–1.38). These associations remained statistically significant even after adjustment for age and sex. The prevalence of OSA in the sampled population was high. These findings suggest the need for more data regarding prevalence of obstructive sleep apnea in Romanian patients with type 2 diabetes. Furthermore, associations found may form a basis to develop specific recommendations for screening of sleep apnea in patients with type 2 diabetes from Romania.     

Overlap syndrome: an indication for sleep studies?

Background  

The coexistence of obstructive sleep apnea (OSA) and chronic obstructive pulmonary diseases (COPD) is known as overlap syndrome (OS); it occurs in 10–20% of patients with OSA. Patients with OS have a higher risk of pulmonary hypertension and worse nocturnal hypoxemia than those with either disease alone. Differences may be seen according to severity of COPD, anthropometric measures, and polysomnography (PSG) features of patients. Recent studies have suggested that long-term use of continuous positive airway pressure for OSA is associated with worsening of coexistent COPD. This stresses the importance of identifying this subgroup of patients in order to provide adequate therapy.     

Obstructive Sleep Apnea and Chronic Opioid Use

The use of opioids has been associated with development of sleep-disordered breathing, including central apneas, nocturnal oxygen desaturations, and abnormal breathing patterns. We describe sleep-disordered breathing and its subsequent treatment in a group of obstructive sleep apneic patients on chronic opioid therapy. Clinical evaluation followed by diagnostic overnight polysomnogram was performed in subjects on chronic opioid therapy who met the study criteria. All subjects had an initial CPAP titration followed by a repeat clinical evaluation. Subjects with an apnea-hypopnea index (AHI) ≥ 5 continued to report symptoms and had follow-up titration with bilevel positive therapy; then bilevel positive-pressure therapy with a back-up rate was then performed. Age-, sex-, and disease-severity-matched obstructive sleep apnea patients served as controls. Forty-four study participants, including a large group of women (50%), and 44 controls were enrolled in the study. Opioid subjects had AHI = 43.86 ± 1.19, with a central apnea index of 0.64 ± 1.36. Two abnormal breathing patterns were seen, including decreased inspiratory effort during an obstructive event and longer than expected pauses in breathing. Despite adequate titration with CPAP and bilevel positive-pressure therapy, nocturnal awakenings and central apnea awakenings persisted (AHI and central apnea indices of 13.81 ± 2.77 and 11.52 ± 2.12, respectively). Treatment with bilevel positive-pressure therapy with a back-up rate controlled the problem. Nonobese OSA patients with opioid intake have obstructive breathing with a different pattern. In this study, bilevel positive-pressure therapy with a back-up rate was the most effective treatment.     

Clinical diagnosis of sleep apnea based on single night of polysomnography vs. two nights of polysomnography

Purpose  The purpose of this study was to investigate apnea–hypopnea index (AHI) across two polysomnographies (PSGs) to examine AHI variability and impact on clinical diagnosis. Materials and methods  Two-night PSGs of 193 sleep clinic patients were reviewed, and the AHI variability was analyzed. Anonymized records from five patients with significant night-to-night AHI variability were used in this study: the two-night PSGs from two patients were represented as four individual PSGs; the two-night PSG for two others were represented as being obtained from two different sleep clinics; the last patient’s PSG was shown as a two-night study. Twenty-two sleep experts attending the Associated Professional Sleep Societies meeting were recruited to make diagnoses based on the PSGs. They were told that the PSGs were from seven patients: four with single-night PSG; two with two PSGs, each one from a different clinic; and one patient with a two-night PSG. Results  Twenty-one percent of the 193 sleep clinic patients had a nightly PSG AHI variability of greater than 5. Forty-eight percent of all patients had a significantly higher AHI on the first night, and 41% had a significantly higher AHI on the second night. Using an AHI > 15 diagnostic criteria, sleep apnea would have been undetected in 20% (n = 39) of patients due to low AHI on one night. Furthermore, 13% of all patients had a more severe sleep apnea classification based on the second night of PSG. For the seven cases, 27–36% of sleep experts failed to identify sleep apnea especially when presented with the PSG containing the lower AHI. Incidences of missed sleep apnea diagnoses were reduced to 15–18% when information from two PSGs was presented to the sleep experts. Conclusions  Utilizing a large patient population, this study supports the significant night-to-night variability in PSG respiratory variables. Identification of sleep apnea in some patients is reduced when sleep experts are provided with only one PSG recording. The clinical implication is that about 13% of sleep clinic patients might benefit from a second night of PSG. Disclosure statement: This study did not receive external funding.     

Integrating Systematic Chronic Care for Diabetes into an Academic General Internal Medicine Resident-Faculty Practice

Background  The quality of care for diabetes continues to fall short of recommended guidelines and results. Models for improving the care of chronic illnesses advocate a multidisciplinary team approach. Yet little is known about the effectiveness of such models in an academic setting with a diverse patient population and resident physicians participating in clinical care. Objective  To implement a chronic illness management (CIM) practice within an academic setting with part-time providers, and evaluate its impact on the completion of diabetes-specific care processes and on the achievement of recommended outcomes for patients with diabetes mellitus. Design  Retrospective cohort study Subjects  Patients with the diagnosis of diabetes mellitus who receive their primary care in an academic general internal medicine resident-faculty practice. Measurements  Process and outcomes measures in patients exposed to the CIM practice were compared with non-exposed patients receiving usual care. Main Results  Five hundred and sixty-five patients met inclusion criteria. Patients in the CIM practice experienced a significant increase in completion of care processes compared to control patients for measurement of annual low-density lipoprotein (LDL) cholesterol (OR 3.1, 95% CI 1.7–5.7), urine microalbumin (OR 3.3, 95% CI 2.1–5.5), blood pressure (OR 1.8, 95% CI 1.1–2.8), retinal examination (OR 1.9, 95% CI 1.3–2.7), foot monofilament examination (OR 4.2, 95% CI 3.0–6.1) and administration of pneumococcal vaccination (OR 5.2, 95% CI 3.0–9.3). CIM-exposed patients were also more likely to achieve improvements in clinical outcomes of glycemic and blood pressure control reflected by hemoglobin A1c less than 7.0% (OR 1.7, 95% CI 1.02–3) and blood pressure less than 130/80 (OR 2.8, 95% CI 2.1–4.5) compared to controls. Conclusions  A systematic chronic care model can be successfully integrated into an academic general internal medicine practice and may result in improved processes of care and some clinical outcomes for diabetic patients. This study provides a model for further hypothesis generation and more rigorous testing of the quality benefits of structured chronic illness care in diverse outpatient practices.     

Continuous Positive Airway Pressure Improves Sleep Apnea Associated Fatty Liver

Treatment of sleep apnea can improve liver enzyme abnormalities in patients with nonalcoholic fatty liver disease. However, the effect of continuous positive airway pressure therapy for sleep apnea on liver fat accumulation was not assessed. Liver biopsy is the “gold standard” for determining and quantifying liver fat accumulation; however, obtaining two separate liver biopsies is challenging. We examined, using a newly described computerized tomography method to quantify liver fat accumulation, whether treatment of sleep apnea improves liver steatosis. In a prospective cohort study, patients diagnosed with obstructive sleep apnea, at Assaf Harofeh Medical Center’s sleep laboratory, were identified. Patients completed a questionnaire and underwent blood tests for liver enzymes and lipid profile, and computed tomography scans to determine the liver attenuation index. Patients with liver attenuation index ≤−10 (correlating with histological macrovesicular steatosis ≥30%) were treated with continuous positive airway pressure for 2–3 years. Subsequently, patients underwent repeat blood tests and tomography scans. Of 47 patients who were analyzed, 16 had a low liver attenuation index (≤−10). Patients with moderate–severe sleep apnea had worse liver attenuation index compared with patients with mild sleep apnea despite comparable body mass index and triglycerides levels. Patients who were compliant with 2–3 years of continuous positive airway pressure treatment demonstrated significant improvement in the mean liver attenuation index, whereas noncompliant patients did not. Patients with nonalcoholic fatty-liver disease may benefit from identification and treatment for obstructive sleep apnea because treatment may improve liver steatosis.     

Risk Factors for Hypoxemia During Ambulatory Gastrointestinal Endoscopy in ASA I–II Patients

Background Most studies identify the American Society of Anesthesiology (ASA) classification as the most significant risk factor for hypoxemia. The risk factors operative within ASA I and II patients are not well defined. Therefore, we analyzed prospectively collected data to identify the risk factors of hypoxemia in such patients. Methods A combination of a narcotic and benzodiazepine was used for sedation and oxygen was supplemented if hypoxemia (oxygen saturation ≤90%) developed. Univariate and multivariate analyses were performed and correlations estimated for predetermined clinical variables. Results 40 of 79 patients (51%) developed hypoxemia, which occurred more frequently in the obese (71%; 10/14) than the nonobese (46%; 30/65) group (P = 0.08). On multivariate analysis, the odds ratios (OR) and 95% confidence intervals (CI) for developing hypoxemia were age ≥ 60 years 4.5 (1.4–14.3) P = 0.01, and incremental 25-mg doses of meperidine 2.6 (1.02–6.6) P = 0.04. Body mass index (BMI) significantly correlated with the number of hypoxemic episodes (rho 0.26, 95% CI 0.04–0.48, P = 0.02). Conclusion In ASA I and II patients, BMI significantly correlated with the number of hypoxemic episodes, whereas age ≥ 60 years and meperidine dose were significant risk factors for hypoxemia.     

Are Opioid Dependence and Methadone Maintenance Treatment (MMT) Documented in the Medical Record? A Patient Safety Issue

BACKGROUND  Opioid-dependent patients often have co-occurring chronic illnesses requiring medications that interact with methadone. Methadone maintenance treatment (MMT) is typically provided separately from medical care. Hence, coordination of medical care and substance use treatment is important to preserve patient safety. OBJECTIVE  To identify potential safety risks among MMT patients engaged in medical care by evaluating the frequency that opioid dependence and MMT documentation are missing in medical records and characterizing potential medication-methadone interactions. METHODS  Among patients from a methadone clinic who received primary care from an affiliated, but separate, medical center, we reviewed electronic medical records for documentation of methadone, opioid dependence, and potential drug-methadone interactions. The proportions of medical records without opioid dependence and methadone documentation were estimated and potential medication-methadone interactions were identified. RESULTS  Among the study subjects (n = 84), opioid dependence documentation was missing from the medical record in 30% (95% CI, 20%–41%) and MMT documentation was missing from either the last primary care note or the last hospital discharge summary in 11% (95% CI, 5%-19%). Sixty-nine percent of the study subjects had at least 1 medication that potentially interacted with methadone; 19% had 3 or more potentially interacting medications. CONCLUSION  Among patients receiving MMT and medical care at different sites, documentation of opioid dependence and MMT in the medical record occurs for the majority, but is missing in a substantial number of patients. Most of these patients are prescribed medications that potentially interact with methadone. This study highlights opportunities for improved coordination between medical care and MMT.     

Use of flow–volume curves to predict oral appliance treatment outcome in obstructive sleep apnea: a prospective validation study

Purpose  

Flow–volume curves have been shown to relate to upper airway physiology during sleep and may be useful for predicting the response to treatment of obstructive sleep apnea (OSA) with mandibular advancement splints (MAS). The aim of this study was to prospectively assess the potential clinical utility of a previously derived prediction method using flow–volume curves performed during wakefulness.     

慢性阻塞性肺疾病患者睡眠呼吸紊乱类型及其与呼吸中枢反应性的关系

目的分析重叠综合征[慢性阻塞性肺疾病（COPD）合并睡眠呼吸暂停低通气综合征（SAHS）]患者睡眠呼吸紊乱的特点，并探讨其与呼吸中枢反应性的关系。方法对300例稳定期COPD患者经问卷、Epworth嗜睡量表及家庭血氧饱和度监测，对氧减饱和指数〉5次／h或嗜睡评分≥10分的患者进行多导生理记录仪睡眠呼吸监测，其中呼吸暂停低通气指数（AHI）≥10次／h的患者有79例（重叠综合征组）。选择年龄、性别及体重指数与其相匹配的118例单纯SAHS患者（SAHS组），对比分析其睡眠呼吸紊乱的特点。另外测定重叠综合征组22例患者的呼吸中枢高CO2反应性和低氧反应性，并与300例COPD患者中17例和SAILS组中17例的相应检测结果进行比较。结果40％（32／79）的重叠综合征患者在睡眠过程中出现延续时间〉1min的持续肺泡通气不足，但单纯SAHS患者此种现象很少见。重叠综合征组的低通气指数占AHI百分比[（69±30）％]、总低通气时间占总睡眠时间百分比[（15±12）％]均较单纯SAHS组[（52±31）％、（12±10）％]明显增高。重叠综合征患者在清醒状态下的△呼气流量／△动脉血氧饱和度[（-0．11±0．05）L·min^-1·％^-1]和△呼气流量／△动脉血二氧化碳分压[（1．1±0．8）L·min^-1·mmHg^-1（1mmHg=0．133kPa）]均明显低于单纯SAHS患者[（-0．35±0．24）L·min^-1·％^-1和（1．6±0．8）L·min^-1·mmHg^-1]。结论重叠综合征患者的睡眠呼吸紊乱模式以低通气为主，其清醒时呼吸中枢的低氧反应性降低。     

Predictors for splenectomy among patients with primary chronic immune thrombocytopenia: a population-based cohort study from Denmark

We conducted a nationwide cohort study of adult Danish patients with primary chronic immune thrombocytopenia (cITP) to examine selected patient and clinical characteristics as predictors for splenectomy. We analyzed data from the Danish National Patient Registry and patient medical records from 1996 to 2007. Using Cox regression analyses, we calculated incidence rate ratios (IRRs) and associated 95% confidence intervals (CI) for splenectomy. We included 371 adult cITP patients. Of these, 87 patients (23%) underwent a splenectomy during a median of 3.6 years of follow-up. The majority (84%) of cITP patients who underwent splenectomy had splenectomy within the first year after cITP diagnosis. Predictors for splenectomy included age ≤75 years (adjusted 1-year IRR = 6.79 (95% CI, 2.10–21.90)) at least one platelet count ≤30 × 10⁹/L (i.e., high disease activity; adjusted 1-year IRR = 2.67 (95% CI, 1.37–5.22)) during follow-up and year of cITP diagnosis in early period (1996–2001; adjusted 1 year IRR = 2.37 (95% CI, 1.46–3.85)). Presence of chronic comorbidity was associated with lower rates of splenectomy (adjusted 1 year IRR = 0.58 (95% CI, 0.33–1.05)). Our findings suggest that high disease activity and absence of chronic comorbidity may be associated with higher rates of splenectomy, and that contraindications for splenectomy (i.e., patients’ perceived frailty) cause the physicians to use the procedure cautiously.     

Posttraumatic Stress and Complicated Grief in Family Members of Patients in the Intensive Care Unit

Background  Family members of patients in intensive care units (ICUs) are at risk for mental health morbidity both during and after a patient’s ICU stay. Objectives  To determine prevalences of and factors associated with anxiety, depression, posttraumatic stress and complicated grief in family members of ICU patients. Design  Prospective, longitudinal cohort study. Participants  Fifty family members of patients in ICUs at a large university hospital participated. Measurements  We used the Control Preferences Scale to determine participants’ role preferences for surrogate decision-making. We used the Hospital Anxiety and Depression Scale, Impact of Event Scale, and Inventory of Complicated Grief to measure anxiety and depression (at enrollment, 1 month, 6 months), posttraumatic stress (6 months), and complicated grief (6 months). Results  We interviewed all 50 participants at enrollment, 39 (78%) at 1 month, and 34 (68%) at 6 months. At the three time points, anxiety was present in 42% (95% CI, 29–56%), 21% (95% CI, 10–35%), and 15% (95% CI, 6–29%) of participants. Depression was present in 16% (95% CI, 8–28%), 8% (95% CI, 2–19%), and 6% (95% CI, 1–18%). At 6 months, 35% (95% CI, 21–52%) of participants had posttraumatic stress. Of the 38% who were bereaved, 46% (95% CI, 22–71%) had complicated grief. Posttraumatic stress was not more common in bereaved than nonbereaved participants, and neither posttraumatic stress nor complicated grief was associated with decision-making role preference or with anxiety or depression during the patient’s ICU stay. Conclusions  Symptoms of anxiety and depression diminished over time, but both bereaved and nonbereaved participants had high rates of posttraumatic stress and complicated grief. Family members should be assessed for posttraumatic stress and complicated grief.     

Autoantibodies against oxidized low-density lipoprotein and lipid profile in patients with chronic periaortitis: case�Ccontrol study

Chronic periaortitis is thought to result from an autoallergic reaction to oxidized low-density lipoprotein (OxLDL). No data exist on lipid profile and atherosclerotic biomarkers. We investigated circulating levels of OxLDL and of anti-OxLDL (aOxLDL) antibodies in patients with chronic periaortitis using the cross-sectional case–control study on 20 patients with chronic periaortitis. Patients were compared to 20 age- and sex-matched controls. aOxLDL antibodies were measured by ELISA and expressed as mean optical density values at 450 nm from duplicate measurements (OD₄₅₀). aOxLDL antibody titers (median [interquartile range]) did not differ significantly between patients and controls (aOxLDL-IgM: 0.70 [0.24–1.08] vs. 0.54 [0.25–0.73] OD₄₅₀; aOxLDL-IgG: 0.59 [0.38–0.75] vs. 0.41[0.33–0.63]OD₄₅₀). Female patients had higher aOxLDL-IgM levels than male patients (1.02 [0.46–1.38] vs. 0.29 [0.22–0.84] OD₄₅₀; P = 0.05). aOxLDL-IgM titers were lower in patients with cardiovascular disease (CVD) than in patients without CVD (0.22 [0.16–0.37] vs. 0.92 [0.70–1.30] OD₄₅₀; P = 0.003) and correlated positively with HDL-cholesterol (r = 0.47, 95% CI 0.02–0.69; P = 0.03) and inversely with diastolic blood pressure (r = −0.46, 95% CI −0.75 to −0.01; P = 0.03) and OxLDL/apoB ratio (r = −0.41, 95% CI −0.73 to 0.04; P = 0.06). No differences or associations were found between aOxLDL-IgG titers and other variables between or within patients and/or controls. In patients OxLDL levels correlated with smoking pack-years (r = 0.58, 95% CI 0.17–0.81; P = 0.007). Data suggest a differing innate immune response to OxLDL in patients with chronic periaortitis compared to controls. Whether this response is causally related to chronic periaortitis development remains to be clarified.     

Central serous chorioretinopathy and risk for obstructive sleep apnea

Patients with obstructive sleep apnea (OSA), in comparison to controls, have increased levels of circulating epinephrine and norepinephrine, both of which are risk factors for the development of central serous chorioretinopathy (CSCR). The aim of this pilot study was to investigate the frequency of symptoms that suggest OSA in CSCR patients and normal controls. The Berlin Questionnaire, a validated research tool to assess risk for OSA, was administered to 29 patients who met the criteria for active, acute, non-steroid-induced CSCR and 29 controls matched for age and sex. In this retrospective case-controlled study, the main outcome measure was increased risk for OSA. The mean age of the patients was 47.8 years (range 29–72) and the mean age of controls was 47.3 years (range 25–70). Seventy-six percent (22) of both groups were men. Survey scores showed 58.6% (17) of patients with CSCR to be at an increased risk for OSA compared to 31.0% (nine) of controls. A conditional logistic regression analysis showed that the CSCR group had a higher proportion with an increased risk for OSA compared to the control group (odds ratio=3.67; 95% CI: 1.02, 13.14; P = 0.046). Patients with CSCR may be more likely than other adults to have OSA, and screening for this sleep disorder should be considered in this population. Further research is warranted to determine whether sleep apnea may contribute to the development of CSCR, and to assess whether treatment of sleep apnea might offer a new therapeutic option for some patients with CSCR.     

Apnea duration and hypoxemia during REM sleep in patients with obstructive sleep apnea

Nocturnal sleep studies of 12 patients with obstructive sleep apnea and a matched control group of 12 subjects without the sleep apnea syndrome were analyzed to compare arterial oxyhemoglobin saturation (SaO2) during REM and non-REM sleep. Mean percentage of total sleep time spent in REM sleep was not significantly different in patients with obstructive sleep apnea and in subjects without significant apnea (14.2 +/- SEM 2.2 percent in patients vs 12.0 +/- 2.2 percent in nonapnea subjects). Apneas were longer during REM than non-REM sleep in all 12 patients (p less than 0.01). Oxyhemoglobin desaturations were more frequent during REM than non-REM sleep in both apnea patients and the control subjects. In addition, there was a greater mean fall in SaO2 per desaturation episode in both the apnea patients and non-apnea subjects. We conclude: 1) sleep apneas are longer during REM sleep than non-REM sleep in patients with obstructive sleep apnea; 2) hypoxemia is greater during REM sleep than non-REM sleep in subjects with and without the sleep apnea syndrome.