REM sleep behavior disorders in multiple system atrophy

We report the results of clinical and polysomnographic investigations on 39 consecutive multiple system atrophy (MSA) patients. Twenty-seven patients (69%) reported nocturnal motor paroxysmal episodes related to dreams, suggesting the clinical diagnosis of REM sleep behavior disorder (RBD). In 12 of them (44%), RBD preceded the clinical onset of the disease by more than 1 year. In seven (26%), the RBD onset was concomitant with and in eight (30%) was at least 2 years after the appearance of motor or autonomic symptoms. On polysomnographic recordings, 35 of 39 MSA patients (90%) had RBD. Other polysomnographic findings included nonclinical obstructive sleep apnea in 6 patients, laryngeal stridor in 8 patients, and periodic limb movements during sleep in 10 patients. Our data show that RBD represents the most common clinical sleep manifestation and polysomnographic finding in patients with MSA. RBD can frequently herald the appearance of other MSA symptoms by years. Extended polysomnographic montages are recommended in MSA sleep studies.     

Sleep-disordered breathing in children with myelomeningocele

BACKGROUND: Although patients with myelomeningocele and the Chiari II malformation are known to have sleep apnea and respiratory control deficits, the prevalence, types, severities, and associations of sleep-disordered breathing (SDB) have not been adequately defined. METHODS: A cross-sectional study of our myelomeningocele clinic population was undertaken to correlate polysomnographic results with historical data and findings from magnetic resonance imaging of the Chiari malformation, pulmonary function results, and nocturnal pulse oximetry. RESULTS: A questionnaire survey of symptoms was available for 107 of 109 children (98% of the clinic population), and 83 patients agreed to undergo overnight polysomnography. Breathing during sleep was classified as normal in 31 cases (37%), mildly abnormal in 35 cases (42%), and moderately/severely abnormal in 17 cases (20%). Among the 17 patients with moderately/severely abnormal SDB, 12 patients had predominantly central apneas and 5 had predominantly obstructive apnea. Patients with a thoracic or thoracolumbar myelomeningocele, those who had previously had a posterior fossa decompression operation, those with more severe brain-stem malformations, and those with pulmonary function abnormalities were more likely to have moderately/severely abnormal SDB, relative risks (95% confidence intervals) 9.2 (2.9 to 29.3), 3.5 (1.3 to 8.9), 3.0 (0.9 to 10.5), and 11.6 (1.6 to 81.3), respectively. Failure of obstructive SDB to resolve after adenotonsillectomy in four patients suggested abnormal control of pharyngeal airway patency during sleep. Nocturnal pulse oximetry accurately predicted moderately/severely abnormal SDB with a sensitivity of 100% and a specificity of 67%. CONCLUSIONS: The pathogenesis of SDB in patients with myelomeningocele involves the functional level of the spinal lesions, congenital and acquired brainstem abnormalities, pulmonary function abnormalities, disorders of upper airway maintenance, and sleep state. Polysomnography and nocturnal pulse oximetry should be performed in high-risk patients to detect and classify SDB.     

Complications associated with the implantation of polypropylene mesh in dogs and cats: a retrospective study of 21 cases (1984-1996)

The reproducibility of overnight polygraphic recording with oximetry, the use of a static charge-sensitive bed (SCSB), thermistors and a body position sensor was assessed in diagnosing obstructive sleep apnoea syndrome (OSAS). Forty-six patients with a clinical suspicion of OSAS underwent a repeat recording. No treatment for OSAS and no change in patient characteristics was allowed between duplicate nights. Between repeated recordings significant correlations were found for ODI4, time spent at SaO2 < 90% and the mean nadir SaO2. Good agreement was found in concordance of classification of ODI4, time spent at SaO2 < 90% and body movements. The combination of oximetry, thermistors, SCSB and body position sensor has a good reproducibility as an affordable screening method in the evaluation of OSAS.     

Screening of sleep apnea/hypopnea syndrome by home pulse oximetry

We evaluated the diagnostic accuracy and reproducibility of results obtained by home oximetry for the screening of sleep apnea/hypopnea syndrome. Our subjects were 40 patients who underwent home oximetry (12 patients for 1 night, 28 patients for 2 nights) followed by all-night polysomnography. Their mean age was 50.7 +/- 11.2 years; mean body mass index (BMI), 27.6 +/- 4.4 kg/m2; and mean apnea/hypopnea index (AHI), 36.0 +/- 26.0 hr-1. The data obtained by home pulse oximetry were fed into a personal computer, and utilized to calculate the desaturation cycles per hour (oxygen desaturation index (ODI) of 2-4%) and the percentage of time that SpO2 measured less than 90% (T 90). Polysomnography was used to monitor the number of apnea and hypopnea episodes per hour of sleep (AHI). With sleep apnea/hypopnea syndrome defined as AHI > or = 15, the diagnostic sensitivity and specificity of home pulse oximetry were 73.5% and 83.3%, respectively, when ODI-3 > or = 15 was used as the diagnostic standard. Patients who showed false negative results had a lower mean BMI (25.5 +/- 3.0) than those who showed true positive results (28.8 +/- 4.6). The reproducibility of ODI-3 data obtained at home was very high (r = 0.964, n = 28). In conclusion, home pulse oximetry seems to be a very useful tool for the detection of apnea/hypopnea syndrome, but false negative results should be considered a possibility, especially in patients who are not obese.     

Comparison of partially attended night time respiratory recordings and full polysomnography in patients with suspected sleep apnoea/hypopnoea syndrome

BACKGROUND: Laboratory full polysomnography (PSG) is considered to be the gold standard for the diagnosis of the sleep apnoea/hypopnoea syndrome (SAHS), but it is expensive and time consuming. A study was undertaken to evaluate the diagnostic usefulness of a partially attended night time respiratory recording (NTRR) and a clinical questionnaire in patients with suspected SAHS in comparison with full PSG. METHODS: Seventy six patients (54 men) of mean (SD) age 51 (11.5) years with a body mass index of 31 (5.7) kg/m2 were studied at random on two different nights with full PSG at the sleep laboratory and with NTRR on a respiratory ward. NTRR records oximetry, airflow, chest and abdominal motion. All signals were continuously displayed on a computer screen throughout the night and respiratory events were scored automatically the following morning. All patients completed a clinical questionnaire. RESULTS: Mean values of the apnoea/hypopnoea index (AHI) using NTRR were lower than those obtained with full PSG (22.7 (2.4) versus 32.2 (3) events/hour) which was mainly due to underrecognition of hypopnoeas. Sensitivity and specificity of NTRR for the diagnosis of SAHS were 82% and 90%, respectively, taking as reference AHI > 10 on full PSG (AHI-PSG > 10). The mean (+/-2SD) difference in AHI between the two methods was 9.6 (range -5.4-24.6) (95% confidence interval 6.2 to 13). Symptoms of witnessed apnoeas, impotence, the overall clinical impression of a trained physician, and a neck size over 40 cm were significantly more prevalent in patients with AHI-PSG of > 10, but impotence was the only clinical feature significantly more prevalent in patients with false negative compared with true negative NTRR results that helped to distinguish patients with NTRR < 10 but AHI-PSG > 10. CONCLUSIONS: NTRR is a helpful and easy complementary diagnostic tool in clinical practice because it detects patients with moderate to severe SAHS reasonably well and therefore can be useful for confirming a diagnosis of SAHS and also for treatment decisions. It is suggested that patients with suspicion of SAHS should be initially studied by NTRR. When NTRR is negative, a full PSG should be performed if witnessed apnoeas, impotence, systemic hypertension, ischaemic heart disease, and a trained physician's clinical impression of SAHS are present.     

Effects of body position on sleep related disordered breathing in a patient with Steinert's disease

Sudden changes in respiratory patterns observed during polysomnographic studies may suggest a positional form of SAHS (sleep apnea-hypopnea syndrome). We report the case of a 37-year-old patient with Steinert's disease with this form of SAHS. Breathing during sleep could be regularized by a simple positional control.     

Successful weaning from mechanical ventilation in an aged subject with severe apneas due to brain damage

A 73-year-old male was admitted to Tokyo University Hospital due to cardiac arrest secondary to ventricular arrhythmias. Although the patient survived after cardiopulmonary resuscitation, he needed mechanical ventilation. When we tried to wean the patient from mechanical ventilation, we found that he suffered from frequent sleep apneas of over 40 times/hour. To evaluate the severity and frequency of the apneas, we performed polysomnographic study on the patient under assist ventilation. The polysomnographic study revealed that frequency of apneas was very high but the magnitude of desaturation was not so severe during the night. Since we confirmed the lowest SaO2 in this patients was over 90% during day and night, we tried to wean from the patient from the ventilator again and succeeded. The clinical application and usefulness of nocturnal ventilatory monitoring for patients with mechanical ventilation was discussed.     

Heart and lung retransplantation: should it be done?

STUDY OBJECTIVES: To evaluate unattended full polysomnography (PSG) recorded in the home by the DigiTrace Home Sleep System (DHSS) and to assess the ability to acquire, store and analyze polysomnographic data using the DHSS compared to standard paper PSG. DESIGN: Part 1 used a prospective, cross-over design. Part 2 consisted of a prospective concurrent collection of polysomnographic data. SETTING: Sleep Disorders Center in a university medical center. PARTICIPANTS: All adult patients who required standard clinical PSG as part of their clinical evaluation, regardless of suspected diagnosis, except patients requiring video recording for abnormal behaviors. MEASUREMENTS AND RESULTS: The DHSS is a digital recording system with miniature preamplifiers and the capacity to record 18 channels of polysomnographic data, including 4 channels of EEG (C3-A2, C4-A1, C3-O1 and C4-O2), right and left EOG, two channels of chin EMG, ECG naso-oral airflow, respiratory effort (piezo crystal thoracic and abdominal belts and bilateral interacostal EMG), snore microphone, bilateral anterior tibialis EMG, and body-position sensor. In part 1,77 DHSS home recordings were evaluated. No recordings were lost due to equipment failure and each parameter was scorable in greater than 95% of all epochs. Most of the subjective assessments by questionnaire following each study revealed no difference between the two testing situations. However, patients reported more sleep time and a better overall test experience in the lab. Assessments of sleep quality and morning alertness compared to usual were rated higher in the lab. After completing both studies, more patients preferred the lab study (p < .01), mostly because of minor inconveniences and apprehension regarding acquisition of data during the home study. There was no difference in the assessment of which test most accurately represented their sleep. In Part 2, the DHSS recorded concurrently with paper PSG in the laboratory in 16 patients. The results show no significant differences for any parameter and strong positive correlations for all parameters. CONCLUSION: Using the DHSS, unattended full PSG can be performed in the home with reliable and high quality recordings. Full PSG can be extended to a larger patient population, because it is no longer limited by the number of beds, and there is a reduction in cost due to elimination of overnight staff and facility cost.     

Phenelzine use throughout pregnancy and the puerperium: case report, review of the literature, and management recommendations

Adenotonsillar enlargement (ATE) can cause respiratory disorders during sleep in children. The treatment of choice for ATE is adenotonsillectomy and its efficacy must be assessed based on improvement in symptoms and polysomnographic patterns. We studied 11 children (7 boys and 4 girls, age 5.5 years) whose ATE symptoms were corrected by adenotonsillectomy. Two nighttime polysomnograms (SleepLab) were recorded, one at baseline and one 6 months after adenotonsillectomy. Polysomnographic recordings were analyzed by quantifying 1) only apneic or hypopneic events lasting > or = 10 sec and 2) all respiratory events > or = 5 sec. The most common symptoms were snoring, nocturnal dyspnea and sleep apnea. Symptoms resolved after adenotonsillectomy for most patients. Obstructive events, in particular shorter apneic events (> or = 5 sec) and instances of hypopnea, decreased after surgery. We found no changes in baseline SaO2, although the minimum SaO2 improved and the number of desaturations decreased, above all those stemming from respiratory events.     

Should patients with sleep apnoea/hypopnoea syndrome be diagnosed and managed on the basis of home sleep studies?

The purpose of this study was to analyse the validity and the economic efficiency of a portable monitor of respiratory parameters (PMRP), used in a home setting for the diagnosis of sleep apnoea/hypopnoea syndrome (SAHS). Eighty nine patients with suspected SAHS were studied in two settings: in the sleep laboratory using full-polysomnography (full-PSG); and at the patient's home using a PMRP. In the home setting, 50 patients were assisted by a technician and 39 set up the equipment themselves. SAHS (apnoea/hypopnoea index (AHI) >10 events x h(-1) by means of full-PSG) was diagnosed in 75 of the 89 patients. An acceptable agreement was obtained between the AHI measured by full-PSG and PMRP, according to the Bland and Altman method of concordance (mean bias 2.56; 95% confidence interval 3.25). Sensitivity and specificity of PMRP were adequate for diagnostic purposes; however, their values rely on the prior PMRP-AHI cut-off point selected with reference to full-PSG-AHI >10. The clinical therapeutic decision taken after PMRP agreed with that taken with full-PSG in 79 patients (89%). Although 10% of the studies with an individual set-up needed repetition, both of the domiciliary modalities (with and without a technician's intervention) were, economically, about three times more efficient than full-PSG. In conclusion, we believe that patients with a suspected sleep apnoea/hypopnoea syndrome should initially be studied in a home setting with a portable monitor of respiratory parameters, since it is a reliable method with an acceptable cost-effective profile.     

Augmented very low frequency component of heart rate variability during obstructive sleep apnea

After documenting the presence of obstructive sleep apnea syndrome (OSAS) through polysomnographic monitoring, we performed simultaneous ambulatory recordings of electrocardiogram, oronasal airflow, and pulse oximetry on 12 OSAS patients with normal autonomic nervous function for a period of 24 hours. The power spectrum of heart rate variability was investigated before and during treatments using dental appliances. Freuquency domain analysis showed that the very low frequency component of heart rate (0.008-0.04 Hz) was increased in OSAS patients and that a very low frequency peak appeared during episodes of obstructive sleep apnea. The increase in very low frequency identification was synchronized with episodes of absence of air exchange or hypoxemia (decreased arterial oxygen saturation) that occurred repeatedly at a cycle length of 25-120 seconds in our subjects. Frequency domain analysis of heart rate variability before and during prosthetic mandibular advancement treatment showed that only the very low frequency was significantly decreased during prosthetic mandibular advancement treatment, whereas the other frequencies, i.e. high, low, and ultralow frequency component values, showed no significant changes. Time domain analysis of heart rate variability before and during prosthetic mandibular advancement treatment showed no significant changes in any of these parameters. Frequency domain analysis of heart rate variability during nocturnal sleep, especially investigation of very low frequency and very low frequency peak, can be a noninvasive low-cost approach to diagnose and even better monitor subjects undergoing treatment at home, particularly considering that R-R intervals can be extracted from pulse oximetry and that analysis software programs are already commercially available.     

Concomitant radiotherapy with mitomycin C and bleomycin compared with radiotherapy alone in inoperable head and neck cancer: final report

We evaluated the efficiency of two different treatment procedures with continuous positive airway pressure (CPAP) on sleep, nocturnal breathing characteristics and daytime vigilance in 18 newly diagnosed patients with untreated sleep apnoea/hypopnoea syndrome (SAHS) randomly allocated to two different groups. In group I, the positive pressure (PP) level was set to suppress flow limitation (PFL), while in group II the PP was set at a level that eliminated only apnoea/hypopnoea and snoring (PAHS). At the end of a 3 week period of home CPAP therapy, a follow-up sleep study, vigilance and cognitive tests were made. Overall, PFL was significantly higher than PAHS values (PFL: 10.42.6 cmH2O; PAHS: 8.9+/-2.6 cmH2O; p<0.01, mean+/-SD). We found no difference in sleep quality, nocturnal saturation and apnoea/hypopnoea index, or in daytime vigilance tests between the two groups at the end of the treatment period. However, there was a significantly greater scattering in the changes of sleep latency in group II than in group I. This was associated with a significant difference in the daily duration of nasal CPAP use between the two groups (group I: 7.29+/-0.95 h x day(-1); group II: 6.01+/-0.94 h x day(-1); p=0.01) and with a positive correlation between final maintenance of wakefulness test values and the duration of CPAP use (p<0.05; r=0.55). These results tend to show that correcting flow limitation is associated with a higher observance and a more important efficiency in normalizing daytime vigilance than with conventional nasal continuous positive airway pressure.     

Surgical correction of nasal obstruction in the treatment of mild sleep apnoea: importance of cephalometry in predicting outcome

BACKGROUND: A study was undertaken to determine if cephalometric radiographs could identify those who will benefit from nasal surgery in patients with a sleep apnoea hypopnoea syndrome (SAHS) and chronic nasal obstruction. METHODS: Fourteen patients with SAHS were enrolled. Those with normal posterior airway space and mandibular plane to hyoid bone distances on preoperative cephalometric radiographs were matched with those with abnormal cephalometry for the frequency of sleep disordered breathing and body mass index. Polysomnographic studies (all subjects) and nasal resistance measurements (n = 10) were performed one to three months before and two to three months after surgery (septoplasty, turbinectomy, and polypectomy). RESULTS: There was no difference in the baseline results of the polysomnographic studies between the two groups of patients. Nasal resistance decreased from a mean (SE) value of 2.9 (0.3) cm H2O/l/s before surgery to 1.4 (0.1) cm H2O/l/s after surgery in the normal cephalometry group and from 2.7 (0.3) cm H2O/l/s to 1.3 (0.3) cm H2O/l/s in the other group. The apnoea + hypopnoea index returned to normal (< 10 breathing abnormalities/hour) in all but one subject with normal cephalometric measurements, and sleep fragmentation improved with a decrease in the arousal index from 23.9 (3.3)/hour at baseline to 10.6 (2.5)/hour after surgery. Both of these parameters remained unchanged after surgery in the patients with abnormal cephalometry. CONCLUSIONS: Normal cephalometry is helpful in identifying patients with mild SAHS and nasal obstruction who will benefit from nasal surgery. The presence of craniomandibular abnormalities makes it unlikely that nasal surgery will improve sleep related breathing abnormalities.     

Therapeutic leukapheresis in the patient with leukemia

OBJECTIVE: To predict and optimal level of continuous positive airway pressure (CPAP) in the menagement of obstructive sleep apnea syndrome (OSAS) by relating certain parameters of respiratory disturbance and sleep hypoxemia. METHODS: 18 patients with OSAS (all male, aged 48 +/- 11 yrs) were enrolled in the study. Their actual levels of CPAP (Pm) were determined by a RHK-5500 mode polysomnographic system plus BiPAP (ST/D) system. The actuual Pm was related to the respiratory disturbance index (RDI) or total time of SaO2 < or = 90% (T S90). The correlation regression equations were calculated. 6 patients with OSAS (Group A) were treated with the predicted nasal CPAP (predicted Pm) which was derived from the regression equation, 8-10 hours per night, for 5-7 nights. 13 patients (Group B) receiving nasal CPAP treatment using the actually measured Pm served as control. RESULTS: There was a close positive linear correlation between RDI or T S90 and actual Pm. Symptoms and polysomnographic parameters improved significantly after one course of CPAP treatment in Group A. The efficacy showed no signifcant different as compared with that in Group B. CONCLUSIONS: It was suggested that RDI or T S90 are of value and simple in predicting the pressuure level of CPAP in the management of OSAS with nasal CPAP.     

Sleep-related gastro-oesophageal reflux: provocation with a late evening meal and treatment with acid suppression

BACKGROUND: Two studies were carried out in order to investigate the issue of meal-provoked nocturnal gastrooesophageal reflux. METHODS: In Experiment 1, 20 symptomatic reflux patients underwent both pH and polysomnographic monitoring on two nights. On one night, patients ate a non-provocative meal prior to 19.00 hours, while on the other night patients consumed a late evening meal (21.00 hours). In Experiment 2.17 symptomatic reflux patients were studied using pH and polysomnographic monitoring on two nights subsequent to a late evening provocative meal. On one night, patients received 75 mg of the H2-antagonist ranitidine, while on another night they received a placebo. The data from 12 of the 17 patients studied were used in the analysis. RESULTS: For Experiment 1, no significant differences in the number or duration of reflux events, acid exposure (total %), or polysomnographic measures of per cent of sleep stages between the two nights were observed. The results of the second experiment demonstrated that when given ranitidine, patients experienced significant decrease in acid contact time (total %), and mean duration of reflux events. Subjective reports of discomfort and sleep disturbance were also significantly improved on the drug night. However, significant differences in polysomnographic measures were not observed. CONCLUSIONS: Based on these results, we conclude that in some symptomatic reflux patients a late-night non-provocative meal may not increase the incidence of gastro-oesophageal reflux, and that a low dose of an H2-antagonist is effective in decreasing oesophageal acid contact time following a late evening provocative meal.     

Acute von Willebrand factor secretion from the endothelium in vivo: assessment through plasma propeptide (vWf:AgII) Levels

STUDY OBJECTIVES: Patients with coronary heart disease (CHD) and obstructive sleep apnea may have an increased cardiac risk due to nocturnal myocardial ischemia triggered by apnea-associated oxygen desaturation. Sleep structure in patients with obstructive sleep apnea is fragmented by activation of the central nervous system (CNS) (arousal) due to obstructive apneas. Nocturnal myocardial ischemia may lead to activation of the CNS as well. PATIENTS: Fourteen patients with obstructive sleep apnea and CHD disease and seven patients suffering from obstructive sleep apnea without CHD were studied. Overnight sleep studies and simultaneous six-lead ECG recordings were performed. In addition, sleep studies and ECG recordings were performed with administration of a sustained-release nitrate in these patients in a double-blinded crossover design. RESULTS: Analysis of three nights' recordings revealed 144 episodes of nocturnal myocardial ischemia in six subjects. Five patients had underlying CHD and one patient exhibited diffuse wall defects of the coronary arteries; also, 85.4% of ischemic episodes were concomitant with apneas and oxygen desaturation > 3%, and 77.8% of ischemic episodes occurred during rapid eye movement (REM) sleep, although total amount of REM sleep was only 18% of total sleep time. Mean oxygen saturation was significantly lower (p < 0.05) during apnea-associated ischemic episodes than during nonapnea-associated ischemia (77.3% vs 93.1%). Nitrate administration did not reduce ischemic episodes. Sleep architecture (macrostructure) exhibited a reduction in sleep stages non-REM 3 and 4 and REM sleep. Comparing the microstructure of sleep (arousals) within episodes with and without ischemia but similar criteria like sleep stage, apnea activity, and oxygen saturation, we found significantly more (p < 0.01) and severe (p < 0.001) arousals during periods with myocardial ischemia than during control episodes. In addition, microstructure of sleep was disturbed by myocardial ischemia itself in absence of apneas. CONCLUSION: It is concluded that patients with CHD and obstructive sleep apnea are endangered by apnea-associated ischemia and that these ischemic episodes lead to activation of the CNS and additional fragmentation of sleep. Patients with nocturnal ischemia should be screened for underlying sleep apnea even if nitrate therapy fails.     

Pulmonary hemodynamics in the obstructive sleep apnea syndrome. Results in 220 consecutive patients

We have investigated pulmonary hemodynamics in a large series of consecutive, unselected patients with obstructive sleep apnea syndrome (OSAS). The aims of this study were to evaluate the frequency of pulmonary artery hypertension (PH) in OSAS and to analyze, as far as possible, its mechanisms. Two hundred twenty patients were included on the basis of a polysomnographic diagnosis of OSAS (apnea+hypopnea index > 20). PH, defined by a resting mean pulmonary artery mean pressure (PAP) of at least 20 mm Hg, was observed in 37 of 220 patients (17%). Patients with PH differed from the others with regard to pulmonary volumes (vital capacity [VC], FEV1) and the FEV1/VC ratio that were significantly lower (p < 0.001); PaO2 (64.4 +/- 9.3 vs 74.7 +/- 10.1 mm Hg; p < 0.001); PaCO2 (43.8 +/- 5.4 vs 37.6 +/- 3.9 mm Hg; p < 0.001), apnea+hypopnea index (100 +/- 33 vs 74 +/- 32; p < 0.001), and mean nocturnal arterial oxygen saturation (SaO2) (88 +/- 6% vs 94 +/- 2%; p < 0.001). Patients with PH were also more overweight (p < 0.001). Multiple regression analysis showed that 50% of the variance of PAP could be predicted by an equation including PaCO2 (accounting for 32% of the variance), FEV1 (12%), airway resistance (4%), and mean nocturnal SaO2 (2%). In conclusion, PH is observed, in agreement with previous studies, in less than 20% of OSAS patients. PH is strongly linked to the presence of an obstructive (rather than restrictive) ventilatory pattern, hypoxemia, and hypercapnia, and is generally accounted for by an associated obstructive airways disease. In this regard, the severity of OSAS plays only a minor role.     

Carboxyhemoglobin levels in relation with home heating

To study carboxyhemoglobin levels (HbCO) associated with use of different types of home heating and to evaluate the usefulness of measuring hemoglobin oxygen saturation. Nonsmoking patients with chronic respiratory insufficiency who were initially prescribed home oxygen therapy were enrolled in the study. One hundred four patients were studied in winter and summer (when heating was not used). The control group consisted of 92 hospitalized patients not exposed to carbon monoxide. Of the 104 patients 74.1% were men. Mean age was 72.33 (range 17 to 97 years) and 57.9% lived in rural areas. Mean HbCO in the control group was 1.53 +/- 0.96% (p = 0.01). Among the 39% who burned slack coal for heat, the mean HbCO was 4.63 +/- 2.87%. The 23.7% with central heating had HbCO levels of 2.15 +/- 0.87% (p < 0.0001). Pulse oximetry (SpO2) estimated higher hemoglobin oxygen than direct measurement (SaO2): 87.12 +/- 6% and 83.3 +/- 8%, respectively (p < 0.001). High HbCO concentrations are related to chronic exposure to slack coal fumes. Pulse oximetry, as opposed to SaO2, overestimates hemoglobin oxygen saturation in such cases.     

Sleep quality in Lyme disease

Complaints of chronic fatigue as well as sleep disturbances are prevalent in Lyme disease. We compared polysomnographic measures of sleep in patients with documented Lyme disease with those of a group of age-matched normal control subjects. Eleven patients meeting Centers for Disease Control criteria for late Lyme disease with serologic confirmation by enzyme-linked immunosorbent assay and Western blot without a history of other medical or psychiatric illness and 10 age-matched control subjects were studied. Lyme disease patients and controls underwent 2 nights of polysomnography. Multiple sleep latency testing (MSLT) was performed in the patients. Sleep was staged by standard criteria, and continuity of sleep was assessed for each stage of frequency analysis of consecutive epochs. All patients studied reported sleep-related complaints, including difficulty initiating sleep (27%), frequent nocturnal awakenings (27%), excessive daytime somnolence (73%) and restless legs/nocturnal leg jerking (9%). Greater sleep latency, decreased sleep efficiency and a greater arousal index were noted in Lyme patients. The median length of uninterrupted occurrences of stage 2 and stage 4 non-rapid eye movement (NREM) sleep was less in Lyme patients (6.3 +/- 3.0 epochs in patients vs. 11.4 +/- 4.4 epochs in controls for stage 2, p < 0.01, and 4.3 +/- 4.4 epochs in patients vs. 11.2 +/- 6.3 epochs in controls for stage 4, p < 0.01), indicating greater sleep fragmentation. Mean sleep onset latency during the MSLT was normal (12.7 +/- 5.6 minutes). Three patients demonstrated alpha-wave intrusion into NREM sleep. These sleep abnormalities may contribute to the fatigue and sleep complaints common in this disease.     

In vivo 1H MRS of normal breast and breast tumors using a dedicated double breast coil

OBJECTIVE: To characterize sleep patterns of patients with juvenile rheumatoid arthritis (JRA). METHODS: Sixteen patients with JRA aged 12+/-4 years and 9 controls aged 11+/-3 years underwent a comprehensive evaluation by self-report questionnaire and formal all night polysomnographic recordings. Multiple sleep latency test was performed in 7 patients. RESULTS: Patients had 90% more arousals and awakenings (p<0.01) and the median length of occurrences of uninterrupted sleep in stages 2 and 3 and rapid eye movement (REM) sleep was 60% shorter than in controls (p<0.01). The overall amount of sleep stage shift from deeper to lighter sleep was 23.5+/-10.8 events in patients compared to 14.9+/-4.0 in controls (p<0.05). In 15 of 16 patients 15% of non-REM sleep consisted of alpha-delta (alpha-rating) sleep, compared with less than 1% in controls (p<0.001). Multiple sleep latency test for patients was 10.3+/-2.6 min. There were no differences between JRA and controls in self-reported questions. However, patients reported longer afternoon naps, 1.8+/-1.3 h compared to 0.3+/-0.8 h in controls (p<0.05). CONCLUSION: Objective polysomnographic evidence of abnormal sleep has been confirmed in patients with JRA. Sleep disturbance was associated with daytime sleepiness as evidenced by abnormal multiple sleep latency test and longer afternoon naptime.