Is there a familial association between obstructive sleep apnoea/hypopnoea and the sudden infant death syndrome?

BACKGROUND: One postulated cause of the sudden infant death syndrome (SIDS) is upper airway obstruction during sleep. Several studies have suggested that SIDS may be more common in families with obstructive sleep apnoea/hypopnoea syndrome (OSAHS), but were limited by uncertainty as to whether the deaths were due to SIDS. We have tested the hypothesis that parents of true SIDS cases have an increased frequency of apnoeas and hypopnoeas during sleep. METHODS: The parents of 269 rigorously determined SIDS cases were invited for single night polysomnography and daytime ventilatory control measurement. RESULTS: Parents of 198 cases were identified but 152 did not respond or declined. Fifty five parents of 34 cases were studied and matched for age, height, and weight to 55 subjects from general practice registers. There was no difference in breathing during sleep between the parents of SIDS cases (median (IQR) 5.9 (3.2, 10.7) apnoeas+hypopnoeas/h) and controls (6.7 (4.0, 12.2) apnoeas+hypopnoeas/h; p = 0.47), but the SIDS parents had lower minimum nocturnal oxygen saturation (median (IQR) 92 (89, 93)%) than controls (92 (90, 94)%; p = 0.048). There were no major differences in control of breathing when awake between SIDS parents and controls. CONCLUSIONS: These results provide no evidence to support an association between SIDS and OSAHS. However, the minor impairment of oxygenation during sleep in SIDS parents requires further study.

Nasopharyngeal symptoms and nasal continuous positive airway pressure therapy in obstructive sleep apnoea syndrome.

Nasal problems are often reported during the treatment of obstructive sleep apnoea syndrome (OSAS) with nasal continuous positive airway pressure (nCPAP) and may jeopardize the use of nCPAP. This retrospective study evaluated the frequency of nasopharyngeal symptoms in OSAS patients before and during nCPAP treatment. A questionnaire was sent to all patients (n = 194) with OSAS for whom nCPAP had been prescribed during the years 1990-1995 at the authors' hospital, enquiring about nasopharyngeal symptoms both before and during treatment and nCPAP use. The study population consisted of the 151 patients [128 men and 23 women, median (range) age 54 (31-76) years and body-mass index 34 (17-54) kg/m2] who responded to the questionnaire. Seventy-one percent of patients were still using nCPAP after a median treatment duration of 30 months. The most commonly reported nasopharyngeal symptoms were nasal stuffiness, which was reported by 46% of patients before nCPAP and by 37% during nCPAP, dry nose (39% before and 46% during nCPAP), sneezing (36% and 35%) and rhinorrhoea (21% and 27%). The frequency of nasopharyngeal symptoms did not change with nCPAP treatment. The frequency of nasopharyngeal symptoms before and during nCPAP treatment was similar in those patients who discontinued the treatment (n = 44, 29%) compared with those who continued with nCPAP (n = 107, 71%). Skin problems caused by the mask (50%), airleak from mouth (44%), difficulty in exhaling (29%) and a sensation of suffocation (26%) were also problems associated with nCPAP treatment. Nasopharyngeal symptoms were common in patients with OSAS before nCPAP was started. There was no significant change in the frequency of these symptoms during nCPAP treatment. Nasopharyngeal symptoms did not seem to affect treatment continuation.

Nasopharyngeal symptoms in patients with obstructive sleep apnea syndrome. Effect of nasal CPAP treatment.

BACKGROUND: Nasal side effects are often reported during nasal continuous positive airway pressure (CPAP) treatment of obstructive sleep apnea syndrome (OSAS) and may make the use of nasal CPAP difficult. OBJECTIVE: The aim of this study was to evaluate the effect of nasal CPAP on nasopharyngeal symptoms in OSAS patients. METHODS: The frequency and severity of nasopharyngeal symptoms and signs were prospectively evaluated in 49 consecutive OSAS patients (37 men, 12 women, mean (SD) age 54 (7) years, body mass index 35 (6) kg/m2) immediately before and after 6 months' treatment with nasal CPAP. RESULTS: Nasopharyngeal symptoms were common already before starting nasal CPAP: 74% of patients reported dryness, 53% sneezing, 51% mucus in the throat, 45% blocked nose, and 37% rhinorrhea. During nasal CPAP treatment, severity and frequency of sneezing (75%) and rhinorrhea (57%) increased. This increase was related to the season when nasal CPAP was applied, and was more profound in winter than in summer. Mild abnormalities on rhinoscopy and paranasal sinus X-rays were common both at baseline and at follow-up with no significant change during treatment. CONCLUSIONS: Nasopharyngeal problems were found to be frequent in patients with OSAS before nasal CPAP treatment, and tended to increase during the treatment.

Effect of obesity and erect/supine posture on lateral cephalometry: relationship to sleep-disordered breathing.

Craniofacial and upper airway anatomy, obesity and posture may all play a role in compromising upper airway patency in patients with the sleep apnoea/hypopnoea syndrome. The aim of this study was to investigate the relationship between obesity, facial structure and severity of sleep-disordered breathing using lateral cephalometric measurements and to assess the effect of body posture on cephalometric measurements of upper airway calibre variables in obese and non-obese subjects. Lateral cephalometry was carried out in erect and supine postures in 73 awake male subjects randomly selected from patients referred for polysomnography who had a wide range of apnoea/hypopnoea frequencies (1-131 events x h sleep(-1)). Subjects were divided into non-obese (body mass index (BMI) < 30 kg x m(-2); n=42) and obese (BMI > or = 30 kg x m(-2); n=31) groups. Significant but weak correlations were found between apnoea/hypopnoea index (AHI) and measurements reflecting upper airway dimensions: uvular protrusion-posterior pharyngeal wall (r=-0.26, p<0.05) and hyoid-posterior pharyngeal wall (r=0.26, p<0.05). Multiple regression using both upper airway dimensions improved the correlation to AHI (r=0.34, p=0.01). Obese subjects had greater hyoid-posterior pharyngeal wall distances than non-obese subjects, both erect (42+/-5 versus 39+/-4 mm, respectively (mean+/-SD) p<0.01) and supine (43+/-5 versus 40+/-4 mm, p<0.05). Skeletal craniofacial structure was similar in obese and non-obese subjects. In conclusion, measurements reflecting upper airway size were correlated with the severity of sleep-disordered breathing. Differences in upper airway size measurements between obese and non-obese subjects were independent of bony craniofacial structure.

The effect of clustered versus regular sleep fragmentation on daytime function.

Previously, we found that regular sleep fragmentation, similar to that found in patients with sleep apnoea/hypopnoea syndrome (SAHS), impairs daytime function. Apnoeas and hypopnoeas occur in groups in patients with REM or posture related SAHS. Thus, we hypothesised that clustered sleep fragmentation would have a similar impact on daytime function as regular sleep fragmentation. We studied 16 subjects over two pairs of 2 nights and 2 days. The first night of each pair was for acclimatisation. On the second night, subjects either had their sleep fragmented regularly every 90 s, or fragmented every 30 s for 30 min every 90 min, the remaining 60 min being undisturbed. We fragmented sleep with tones to produce a minimum 3 s increase in EEG frequency. During the days following each pair of nights we tested subjects daytime function. Total sleep time (TST) and microarousal frequency were similar no both study nights. We found significantly less stage 2 (55 SD 4, 62 +/- 7%; P = 0.001) and more slow wave sleep (21 SD 3, 12 +/- 6%; P < 0.001) on the clustered night. Mean sleep onset latency was similar on MSLT (clustered 10 SD 5, regular 9 +/- 4 min; P = 0.7) and MWT (clustered 32 SD 7, regular 30 +/- 7 min; P = 0.2). There was no difference in subjects mood or cognitive function after either study night. These results suggest that although there is more slow wave sleep (SWS) on the clustered night, similar numbers of sleep fragmenting events produced similar daytime function whether the events were evenly spaced or clustered.

Bilateral diaphragmatic weakness: a late complication of radiotherapy.

Brachial plexus neuropathy is an unfortunate complication that sometimes follows radiotherapy to the axillary and supraclavicular regions. A patient is described who, 30 years after radiotherapy for Hodgkin's disease and more than 10 years after the development of radiation-induced bilateral brachial plexus neuropathy, presented with bilateral diaphragmatic weakness secondary to bilateral phrenic nerve weakness. Previous radiotherapy was the most probable cause of the condition.

Nasal-CPAP, surgery, and conservative management for treatment of obstructive sleep apnea syndrome. A randomized study.

STUDY OBJECTIVE: To assess separately the effectiveness and safety of nasal-continuous positive airway pressure (N-CPAP) and that of surgery in comparison to conservative management in patients with obstructive sleep apnea syndrome (OSAS). DESIGN. A randomized study with 1-year follow-up. SETTING: A university hospital acting as a referral center for OSAS. PATIENTS: Symptomatic patients with OSAS (72 male and 4 female patients aged 18 to 65 years), who had oxygen desaturations in the overnight recording. INTERVENTIONS: After the initial diagnostic workup, patients were considered to be candidates for either N-CPAP (44 patients) or surgical treatment (uvulopalatopharyngoplasty [UPPP] with or without mandibular osteotomy) (32 patients). Within the groups, the patients were then randomized to either the assigned treatment or conservative management. MAIN OUTCOME MEASURES: The number of nocturnal oxygen desaturation events of 4% or more per hour in bed (ODI4); daytime somnolence; side effects. RESULTS: N-CPAP Group: Compliance with N-CPAP therapy at 1 year was 13 of 21. The most common reason for noncompliance was general intolerance of CPAP. All compliant patients had a normal ODI4 ( < 10), whereas 1 of 20 of their control subjects had a normal finding. Patients receiving active treatment were significantly less somnolent than their control subjects at 1 year (p < 0.05). SURGERY GROUP: At 1 year, 7 of 18 of the surgically treated and 1 of 14 of the conservatively treated patients had a normal ODI4 (p < 0.001). Daytime somnolence was significantly less severe in the surgically treated patients compared with their control subjects (p < 0.001) both at 3 and 12 months. The overall postoperative complication rate was 22%. CONCLUSIONS: N-CPAP is an effective therapy for OSAS, but compliance is a problem. Surgical therapy (UPPP with or without mandibular osteotomy) needs further evaluation.

Computer assisted detection of REM and non-REM sleep for analysis of nocturnal hypoxaemia in patients with ventilatory impairment.

A computer-assisted method for the evaluation of sleep and breathing in patients showing chronic ventilatory impairment is described and validated. Signals of body and respiratory movements (static charge sensitive bed), air-flow (thermistors), oxygen saturation (SaO2), electro-oculography (EOG), and electromyography (EMG) were recorded overnight and analysed. Using the compressed output graphs of the data and a rapid scoring procedure, stages of wakefulness, non-REM (stages S1-S4) and REM sleep were identified. The procedure allowed analysis of oxygen saturation data separately for each sleep stage. For validation of the method, the sleep stages identified were compared with traditional sleep staging based on a simultaneous recording of EEG, EMG and EOG in 10 patients with chronic obstructive pulmonary disease (COPD) and in 15 patients treated by thoracoplasty (TPL) for pulmonary tuberculosis. The recordings were performed in a patient ward. In total, 32 night recordings were analysed. In the COPD patients, the sensitivity and specificity of the new method were 87% and 84% in detecting non-REM sleep, and 72% and 87% in detecting REM sleep, respectively. In the TPL patients, the sensitivity and specificity were 93% and 89% with respect to non-REM sleep, and 92% and 94% in regard to REM sleep. The new method and traditional sleep staging provided closely similar quantitative estimates of the degree of sleep stage-(REM and non-REM) dependent arterial oxygen desaturation. It is concluded that the computer-assisted method, which is considerably less time consuming than traditional polysomnography, is reliable in studying sleep-related oxygenation in patients with chronic lung diseases.

Acute eosinophilic pneumonia in a heroin smoker.

Inhalation of heroin is known to provoke asthma. We report on the case of a patient who, after repeated inhalation of heroin, presented with decreased lung volume associated with bronchial hyperresponsiveness, diffuse pulmonary infiltrates, and bronchoalveolar lavage fluid eosinophilia. Rapid remission was obtained after heroin abstinence and initiation of corticosteroid treatment.

Nocturnal oxygen saturation and sleep quality in long-term survivors of thoracoplasty.

The extent and the predictors of nocturnal hypoxemia were studied in 9 men and 11 women treated for pulmonary tuberculosis by thoracoplasty 30-54 years previously. The patients had a scoliotic (Cobb) angle of 4-53 degrees. Median values for pulmonary function were: forced expiratory volume in 1 s 1.2 liters (49% of the predicted value), vital capacity 1.9 liters (54%), total lung capacity 3.6 liters (62%), and supine waking partial pressure for arterial oxygen 9.7 kPa. Four patients were hypercapnic. The patients' mean nocturnal SaO2 ranged from 83 to 94% (median 91.8%), and the SaO2 level below which the patients spent 10% of the total nocturnal recording time ranged from 78 to 92% (median 89.4%). A multiple stepwise linear regression analysis identified supine waking SaO2 as a significant predictor of nocturnal O2 desaturation, accounting for about 80% of the variability in nocturnal SaO2 levels; lung function values and Cobb angle were not significant independent predictors. The sleep quality, assessed by EEG, was good. It is concluded that in thoracoplasty patients with mild hypoxemia during wakefulness, the degree of sleep-related oxygen desaturation was modest and closely related to the waking level of SaO2.

Nocturnal oxygen saturation in advanced chronic obstructive pulmonary disease after a moderate dose of ethanol.

The effect of a moderate oral dose of ethanol/(0.5 g.kg-1 body weight) on nocturnal arterial oxygen saturation (SaO2) was evaluated in nine male patients with advanced chronic obstructive pulmonary disease (COPD), (median forced expiratory volume in one second (FEV1) 0.9 l, arterial oxygen tension (PaO2) 9.3 kPa, arterial carbon dioxide tension (PaCO2) 5.3 kPa). During the four study nights (two after alcohol and two after placebo intake), the patients were monitored by whole-night computerized recordings of SaO2 (Biox-oximeter), airflow (thermistors) and respiratory as well as body movements (static charge sensitive bed). After alcohol intake, the mean blood ethanol concentration (SEM) in the evening was 42(2.3) mg.100 ml-1. Alcohol intake was associated with a marginal deterioration of nocturnal oxygenation; the mean (SEM) nocturnal SaO2 was 88.4(2.0) % after alcohol ingestion and 89.1(1.6) % after placebo ingestion, respectively. Only during the first 2 h in bed was there a statistically significant difference in SaO2 in favour of placebo (p less than 0.05). It is concluded that moderate alcohol intake in the evening, corresponding to "social" drinking, did not substantially aggravate nocturnal oxygenation in our patients with advanced COPD and mild to moderate daytime hypoxaemia.

Nocturnal oxygen saturation and sleep quality in patients with advanced chronic obstructive pulmonary disease during treatment with moderate dose CR-theophylline.

The effect of a 24-h controlled-release (CR) preparation of theophylline (Th) on nocturnal arterial oxygen saturation (SaO2) and sleep quality has been evaluated in 7 patients with advanced chronic obstructive pulmonary disease (COPD) in a double-blind cross-over experiment; median values: age 61 y; PaO2 8.0 kPa; PaCO2 5.8 kPa. During treatment with 450-900 mg Th in the evening, morning plasma drug levels ranged from 5.2-12.9 micrograms.ml-1. During Th and placebo treatment, the median evening FEV1 was 0.45 l and 0.46 l, respectively, and the morning FEV1 was 0.53 l and 0.41 l. Sleep was monitored by whole-night polysomnographic recording of oximetric SaO2, airflow, respiratory and body movements (static charge sensitive bed), eye movements and submental electromyogram. There was no significant difference between Th and placebo in sleep quality. Th treatment was associated with a marginal improvement in nocturnal oxygenation in most of the patients; the average nocturnal SaO2 ranged from 84.4%-92.8% during Th and from 82.2-90.5% during placebo treatment, respectively. Only in the morning, during the last 2 h in bed, was the slight difference in SaO2 statistically significant in favour of Th. It is concluded that a moderate dose of CR-theophylline did not alter the sleep quality or substantially improve nocturnal oxygenation in patients with advanced COPD and mild to moderate day-time hypoxaemia.

Fire-eater's lung.

Acute pneumonitis following aspiration of petroleum products is usually related to accidental poisonings in children. We describe here two cases of hydrocarbon pneumonitis in fire-eaters, caused by accidental aspiration of petroleum during the performance of fire-eating. Both patients had cough, dyspnoea, chest pain and fever. Chest X-rays showed basal lung infiltrates and, 2 weeks later, pneumatocele formations. Reversible bronchial hyperresponsiveness and restrictive ventilatory limitation were demonstrated in one of the patients. The bronchoalveolar lavage specimen showed cytoplasmic vacuolation of the macrophages and neutrophilia. After treatment with antibiotics and corticosteroids the symptoms disappeared and the lung function values returned to normal within 2-3 weeks. Radiological resolution of the pneumatoceles occurred within 2-12 months.