The role of the primary care physician in recognizing obstructive sleep apnea.

BACKGROUND: Obstructive sleep apnea (OSA) is a common disorder among middle-aged adults. However, OSA is a recently described disorder for which most primary care physicians do not have formal training. The primary objectives of this article are to evaluate what percentage of patients referred by primary care physicians for sleep studies had OSA; to characterize the clinical features of these patients and compare them with our known OSA population; and to determine whether primary care physicians asked key questions contained in a work sheet to make the diagnosis of OSA. METHODS: A retrospective chart review at a hospital-based sleep center that is accredited to evaluate all sleep disorders, not just OSA. The health maintenance organization is a staff model one. PATIENTS: Sixty-nine patients who were referred for a sleep study by a health maintenance organization internist or family practitioner between June 1, 1994, and May 30, 1995. RESULTS: Ninety-six percent of the 68 patients referred for polysomnography had OSA. Most were very symptomatic and obese. These 68 patients represent 0.13% of the primary care patient panel. In addition, most of the patients were referred by a few physicians; 6 (11%) of the 55 physicians ordered 33% of the 68 studies. CONCLUSIONS: Primary care physicians did recognize obese patients with prominent symptoms of sleep apnea. However, only a small percentage of their patient panel was referred, suggesting that this condition is still underdiagnosed. This seems particularly true as most of the sleep studies were ordered by a small group of physicians. Future work incorporating educational interventions is necessary to improve detection and treatment of OSA.

Environmental noise as a cause of sleep disruption in an intermediate respiratory care unit.

Our laboratory previously reported continuously monitored peak sound levels in several areas at Rhode Island Hospital. The number of sound peaks greater than 80 A-weighted decibels (dBA) was found to be high in the intensive and intermediate respiratory care unit (IRCU) areas, even at night. Environmental noise of this magnitude is potentially sleep-disruptive. Therefore, we hypothesized that nocturnal peak sound levels of > or = 80 dBA would be associated with an increase in EEG arousals from sleep in patients in the IRCU. Six patients underwent sleep monitoring while environmental peak sound levels were continuously recorded. Each 8-hour period (2200 to 0600 hours) was broken down into 30-minute segments. If there were 10 minutes or more of wakefulness in a segment, that segment was dropped from further analysis. Of the remaining 61 segments, there was a very strong correlation (r = 0.57, p = 0.0001) between the number of sound peaks of > or = 80 dBA and arousals from sleep. These 61 periods were then classified as quiet, moderately loud, and very loud based on the number of sound peaks (< or = 5, 6-15, and > 15, respectively). Analysis of variance revealed a significant difference between the number of arousals (p = 0.001) in quiet periods and that in very loud periods. We conclude that environmental noise may be an important cause of sleep disruption in the IRCU.

Depression as a manifestation of obstructive sleep apnea: reversal with nasal continuous positive airway pressure.

Fifty-five patients with obstructive sleep apnea each completed a Zung Self-Rating Depression Scale (SDS), Twenty-five patients (45%) had SDS scores greater than or equal to 50, consistent with depression. The SDS scores did not correlate with age, the number of respiratory events per hour sleep, antihypertensive medication, or the oxygen saturation baseline or nadir. The group with SDS scores of 50 or greater, however, had 68.0 +/- 8.8 respiratory events per hour compared with 47.9 +/- 4.7 in the group with SDS scores under 50 (p less than .05). Nineteen patients who were treated with nasal continuous positive airway pressure completed a follow-up SDS Inventory. After treatment, the SDS scores fell from 60.5 +/- 1.9 to 44.4 +/- 2.6 (p less than .001) in the 11 patients with baseline elevated scores. The authors conclude that obstructive sleep apnea can produce prominent symptoms of depression that appear to be related to the severity of the underlying apnea; furthermore, treatment of obstructive sleep apnea may result in alleviation of these symptoms in certain patients.

Simple predictors of uvulopalatopharyngoplasty outcome in the treatment of obstructive sleep apnea.

STUDY OBJECTIVE: Our objective was to determine whether baseline polysomnography, cephalometry, and anthropometry data could predict uvulopalatopharyngoplasty (UPPP) success or failure. DESIGN: We retrospectively reviewed polysomnography, cephalometry, and anthropometry data from patients who underwent UPPP for obstructive sleep apnea (OSA). SETTING: A university medical center. PATIENTS: OSA was diagnosed by polysomnography in 46 patients who underwent UPPP surgery for their sleep disorder. INTERVENTIONS: UPPP surgery with/or without tonsillectomy. MEASUREMENTS AND RESULTS: The mean patient age was 43 years, and the mean body mass index was 32.5 kg/m(2). The mean presurgical apnea-hypopnea index (AHI) was 45, and the mean baseline nadir oxygen saturation was 81%. Successful surgery was defined as a reduction in AHI to < 10 or to < 20 with a 50% reduction from the patient's baseline AHI. Of the 46 patients, 16 were successfully treated and 30 did not respond to surgical treatment. A mandibular-hyoid distance (MP-H) > 20 mm was found to be significantly (p = 0.05) predictive of failure of UPPP. When stepwise regression analysis was performed utilizing postsurgical AHI as the dependent variable and presurgical AHI, age, body mass index, baseline nadir O(2) saturation, and five cephalometric measurements as independent variables, MP-H distance significantly (r = 0.524; p = 0.01) correlated positively with postsurgical AHI. The distance between the superior point of a line-constructed plane of the sphenoidale (parallel to Frankfort horizontal) and a point at the intersection of the palatal plane perpendicular to the hyoid correlated negatively with postsurgical AHI (r = 0.586; p = 0.05). By creating a logistic model of this data, an MP-H distance < 21 mm, an angle created by point A to the nasion to point B < 3 degrees, and the presence of a baseline AHI < 38 enhanced the predictability of UPPP success. CONCLUSIONS: The presence of a baseline AHI < 38 and an MP-H < or = 20 mm, and the absence of retrognathia are predictors of improvement after UPPP. Based on these findings, we would advocate the continued evaluation of cephalometric measurements and careful consideration of surgical treatment options for OSA.

Daytime hypertension in obstructive sleep apnea. Prevalence and contributing risk factors.

We examined the prevalence of daytime hypertension in a modern sample of patients with obstructive sleep apnea (OSA) and assessed the relative risk factors contributing to the development of hypertension in this disorder. Daytime hypertension was present in 92 (45 percent) of 206 male and female patients with OSA. Stepwise logistic regression revealed that only age and body mass index (BMI) were predictors of hypertension in this population. A subsample of 152 male patients with OSA was then compared to 904 men identified from a geographically and ethnically similar general population. When one controlled for age and BMI, the prevalence of hypertension in the two groups was the same except for those aged 25 to 44 years who were markedly obese (BMI greater than 31 kg/m2). In this group, 47 percent of the patients with OSA were hypertensive vs 26 percent of control subjects (p less than 0.05). Our data suggest that the high prevalence of hypertension in OSA is primarily related to age and the excess obesity seen in these patients. In morbidly obese young patients with OSA, factors directly related to OSA may also be contributing to the development of hypertension. With increasing age, other competitive risks may obscure any independent effect that OSA may exert.

Body fat distribution and sleep apnea severity in women.

The contribution of body fat distribution to sleep-disordered breathing in women has not been examined in detail (to our knowledge). Fifty women under 65 years of age were diagnosed as having obstructive sleep apnea (OSA) by all-night polysomnography in a 6-month period. Twenty-five women underwent body fat measurements of skin folds and circumferences. The 12 premenopausal and 13 postmenopausal women did not differ in regard to apnea hypopnea index (AHI), SaO2 nadir, body mass index (BMI), or anthropometric measurements. The AHI for these 25 patients was related to the severity of obesity assessed by triceps and subscapular skin folds, the sum of the skin folds, waist circumference, and BMI. The SaO2 nadir correlated with triceps and subscapular skin folds, the sum of the skin folds, and neck skin fold. Clinical features of this same group of 25 women were then compared with those of 45 men with OSA previously described by our laboratory. The women, despite similar age, had less severe OSA than the men (AHI of 34.4 +/- 5.4 vs 51.1 +/- 4.9, p < 0.05). Despite similar BMIs and waist circumference, the men had evidence of a greater degree of upper body obesity with a larger subscapular skin fold thickness, waist-hip ratio, and neck circumference. In addition, for a given degree of upper-body obesity, men had more severe sleep apnea. These findings may explain, at least in part, the greater severity of OSA in the men.

Adiposity and cardiovascular risk factors in men with obstructive sleep apnea.

STUDY OBJECTIVE: To assess anthropometric characteristics of patients with obstructive sleep apnea (OSA) and their relationship to cardiovascular risk factors (dyslipidemia, hypertension, glucose intolerance) and severity of breathing abnormalities during sleep. DESIGN: Case series. SETTING: Referral-based sleep disorder center serving Rhode Island and Southeastern Massachusetts. PATIENTS: Forty-five men, 26 to 65 years old, with OSA diagnosed by clinical and polysomnographic criteria. RESULTS: By national health survey criteria, 51 percent of patients were in the upper fifth percentile for weight, whereas 91 to 98 percent were in the upper fifth percentile for skinfold thicknesses (triceps, subscapular, triceps plus subscapular). Severe upper body obesity, as defined by a waist-hip ratio (WHR) greater than or equal to 1.00, was present in 51 percent of the patients. The WHR, however, did not correlate significantly with the severity of respiratory disturbances during sleep. The patients had higher prevalences of hypertension and impaired glucose tolerance than expected, but normal prevalences of hypercholesterolemia, low high-density lipoprotein cholesterol, and overt diabetes mellitus. Skinfold thicknesses correlated more closely with the severity of OSA than did body mass index (BMI) or neck circumference. CONCLUSION: Men with OSA have a marked excess of body fat that is not always reflected in measurements of body weight or BMI. Also, upper body obesity, hypertension, and impaired glucose tolerance occur more frequently than expected in this population. Severe adiposity may not only promote development of the respiratory abnormalities of OSA, but also may contribute directly to the increased cardiovascular risk associated with OSA.

The efficacy of oral appliances in the treatment of persistent sleep apnea after uvulopalatopharyngoplasty.

Twenty-four patients who failed uvulopalatopharyngoplasty (UPPP) for obstructive sleep apnea (OSA) had an adjustable oral (Herbst) appliance made to treat the persistent apnea. Six patients discontinued the device prior to sleep evaluation. Eighteen patients had polysomnographic evaluations at baseline, post-UPPP, and with the Herbst appliance in place. The apnea-hypopnea index baseline (AHI) and arterial oxygen saturation (SaO2) nadir were 42.3+/-6.1 and 83.6+/-1.8%, respectively. There was no significant change in either parameter with surgery. With the oral appliance, the AHI fell to 15.3+/-4.4 (p < or = 0.01) and the SaO2 nadir increased to 87.9+/-1.2% (p < or = 0.05). Ten of the patients had control of the OSA with the Herbst appliance with a fall in the AHI to < 10. There were, in addition, two partial responders as defined by an AHI of <20 and a >50% fall in AHI compared with baseline and post-UPPP values. All but one of the responders and partial responders had complete resolution of subjective symptoms of daytime sleepiness with the appliance. An adjustable oral appliance appears to be an effective mode of therapy to control OSA after an unsuccessful UPPP.

Identification and modification of environmental noise in an ICU setting.

STUDY OBJECTIVES: Noise levels in the hospital setting are exceedingly high, especially in the ICU environment. We set out to determine what caused the noises producing sound peaks > or = 80 A-weighted decibels (dBA) in our ICU settings, and attempted to reduce the number of sound peaks > or = 80 dBA through a behavior modification program. DESIGN: The study was divided into two separate phases: noise identification and a trial of behavior modification. During the noise identification phase we simultaneously recorded sound peaks and the loudest noise heard subjectively by one observer in the medical ICU (MICU) and the respiratory ICU (RICU). During the behavior modification phase of the study we implemented a behavior modification program, geared toward noise reduction, in all of the MICU staff. Sound levels were monitored before and at the end of the behavior modification trial. SETTING: The MICU and RICU of a 720-bed teaching hospital in Providence, RI. PARTICIPANTS: All ICU staff during the study period. INTERVENTIONS: Once the noises that were determined to be amenable to behavior modification were identified, a behavior modification program was conducted during a 3-week period in our MICU. Baseline and post-behavior modification noise recordings were compared in 6-h intervals after sites were matched by number of patients in a room and Acute Physiology and Chronic Health Evaluation II (APACHE II) scores. MEASUREMENTS AND RESULTS: We identified several causes of sound peaks > or = 80 dBA amenable to behavior modification; television and talking accounted for 49%. We also significantly reduced the 24-h mean peak noise level (p=0.0001), as well as the mean peak noise level (p=0.0001) and the number of sound peaks > or = 80 dBA (p=0.0001) in all 6-h blocks except for the 12 AM to 6 AM period. CONCLUSIONS: We conclude that many of the noises causing sound peaks > or =80 dBA are amenable to behavior modification and that it is possible to reduce the noise levels in an ICU setting significantly through a program of behavior modification.

A critical evaluation of RAST to venoms of Hymenoptera.

RAST to venoms were done on 108 sera. Positive RAST to one or more venoms of Hymenoptera found in 51% (41/80) patients with a generalized reaction to the sting of Hymenoptera and in 7% (2/28) of normal controls were critically evaluated. RAST determinations for each sera were done in duplicate and results averaged. The laboratories were not told which sera belonged to patients with allergy to Hymenoptera and which belonged to controls. In ten patients, one half of the original sera were saved and RAST to venoms were repeated approximately 1 1/2 years later. Of our positive RASTSs, 49% (20/41) had positives to more than one type of venom. The most frequent positive RAST was to yellow jacket followed by hornet, wasp, and honey bee. A high degree of cross-reactivity occured between venoms of hornet, wasp, and yellow jacket. The frequency of positive RAST was similar in pre-treatment and post-treatment sera from patients on immunotherapy with whole body extract. Specific IgE (RAST) results to venoms did not correlate with the degree of clinical severity of the sting. However, IgG anti-venom antibodies were not considered. Elevated RAST titres were associated with increased total IgE levels in sera of non-atopic patients. A positive RAST to venoms is frequently found in sera of patients stung within 5 years. RAST scores of 2 to 4 were remarkably reproducible, while scores of 1 were not consistently reproducible. RAST results should be interpreted in conjunction with the clinical history.

Efficacy of nocturnal nasal ventilation in patients with restrictive thoracic disease.

We tested the efficacy of nocturnal nasal ventilation (NNV) using the BIPAP ventilator in patients with restrictive thoracic diseases by withdrawing them from NNV for an average of 1 wk. One male and five female patients were enrolled in the study; four with restrictive chest wall diseases, and two with muscular dystrophies. All patients had chronic CO2 retention (PaCO2 greater than 50 mm Hg) and had been improved by using NNV for at least 2 months before the study. Four patients were switched to the BIPAP ventilator from standard portable volume ventilators at least 1 month prior to the study without changes in gas exchange or symptoms. After withdrawal of NNV, patients had no deterioration in daytime vital signs, pulmonary functions, maximal inspiratory or expiratory pressures, or arterial blood gases compared with measures made immediately before withdrawal and 1 wk after resumption. However, patients had more dyspnea at rest, increased daytime somnolence, more morning headaches, less daytime energy, and felt less rested in the morning during withdrawal of NNV. Furthermore, nocturnal monitoring demonstrated greater tachycardia, tachypnea, oxygen desaturation, and hypoventilation during withdrawal of NNV. We conclude that NNV administered by the BIPAP ventilator is effective in ameliorating nocturnal hypoventilation and daytime symptoms in patients with chronic CO2 retention caused by severe restrictive thoracic diseases. These data also suggest that the efficacy of NNV may depend more on amelioration of nocturnal hypoventilation than on resting of ventilatory muscles.

Efficacy of a Herbst mandibular advancement device in obstructive sleep apnea.

Treatment options for obstructive sleep apnea (OSA) may involve potential side effects or discomfort; nasal continuous positive airway pressure (CPAP) may not be tolerated by 25% of patients. We therefore sought to determine the efficacy of mandibular advancement as a treatment for OSA, and to investigate whether clinical and radiographic parameters can predict the response to this treatment. Sixteen male and 3 female subjects with documented OSA who had failed or been unable to tolerate nasal CPAP underwent baseline polysomnography and cephalometry, and were then fitted with a removable Herbst appliance to achieve forward mandibular advancement during sleep. All subjects then underwent a second cephalometric evaluation and polysomnography with the appliance in place. Fourteen of 15 subjects demonstrated significant improvement in the degree of OSA, based on the apnea-hypopnia index (AHI) (34.7 +/- 5.3 to 12.9 +/- 2.4 events/h, p < 0.002). Comparison of pre- and posttreatment cephalometric values revealed no significant change in the posterior airway space (PAS) despite a reduction in mean AHI. There was a significant decrease in the mandible-hyoid distance (MP-H) with treatment for the group as a whole. When the study population was evaluated on the basis of a successful response to mandibular advancement (posttreatment AHI < 10), the baseline MP-H was found to be significantly shorter in the responders than in nonresponders. MP-H after mandibular advancement was likewise shorter in responders than in nonresponders. In addition, the soft palate length (PNS-P) showed a significantly greater shortening in responders after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in airway resistance following nasal provocation.

Controversy exists on whether stimulation of the nasal mucosa results in reflex bronchoconstriction. To address shortcomings in previous experimental design, we performed double-blind randomized nasal challenges in asthmatic patients with allergic rhinitis and in controls. Using pledgets containing 10-microliters aliquots of 0.9% saline or increasing concentrations of methacholine or histamine, we were able to increase nasal resistance significantly in both groups. Only methacholine caused an increase in lower airway resistance, and this could be blunted by premedication of the nasal mucosa with phenylephrine. This suggests that the effect on lower airway resistance was due to systemic absorption. Our study does not support the existence of a nasobronchial reflex from mechanical alteration of the nasal mucosa.

Nocturnal positive-pressure ventilation via nasal mask in patients with severe chronic obstructive pulmonary disease.

Intermittent positive pressure ventilation administered nocturnally via a nasal mask has been associated with improvements in pulmonary function and symptoms in patients with restrictive ventilatory disorders. We hypothesized that nocturnal nasal ventilation (NNV) would bring about similar improvements in patients with severe chronic obstructive pulmonary disease (COPD). The study used a randomized, crossover design, with subjects undergoing NNV or "standard care" for sequential 3-month periods. Of 23 patients with obstructive lung disease and a FEV1 less than 1 L who were initially enrolled, 4 were excluded because of obstructive sleep apnea prior to randomization. Among the remaining 19 patients, 7 withdrew because of intolerance of the nose mask, 5 were withdrawn because of intercurrent illnesses, and 7 completed both arms of the protocol. These latter 7 patients used the ventilator for an average of 6.7 h/night, and 3 of the 7 had partial relief of dyspnea during ventilator use. However, in comparison with studies performed upon initiation or after the standard care arm of the study, studies performed after 3 months of NNV revealed no improvements in pulmonary function, respiratory muscle strength, gas exchange, exercise endurance, sleep efficiency, quality or oxygenation, or dyspnea ratings. The only improvements observed were in neuropsychological function, possibly related to a placebo effect or another unknown mechanism. Despite the small sample size, our study indicates that NNV is not well tolerated by and brings about minimal improvements in stable outpatients with severe COPD.