Recommendations for research into measurement and classification of sleep disordered breathing: gazing into the crystal ball.
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Humans↗
Biomedical subjects
J W Shepard
Publications and source records attributed to J W Shepard.
The effect of snoring and obstructive sleep apnea on the sleep quality of bed partners.
OBJECTIVE: To measure the effect of snoring and obstructive sleep apnea (OSA) on the sleep of snorers' bed partners and to determine whether a bed partner's sleep improves when snoring and OSA are treated. MATERIALS AND METHODS: We studied 10 married couples in which 1 member was undergoing polysomnography to evaluate suspected OSA. The patients and their spouses underwent simultaneous polysomnography. Midway through the 1-night study, the patients received nasal continuous positive airway pressure (CPAP) with the pressure adjusted to eliminate snoring and obstructive breathing events. Apnea-hypopnea index (episodes/hours of sleep time), arousal index (arousals/hours of sleep time), and sleep efficiency (percent time asleep) were calculated to measure sleep quality. RESULTS: The patients (all male) demonstrated a median (range) apnea-hypopnea index of 26 (3-75) that decreased to 7 (0-34) during the trial of nasal CPAP therapy (P < .05). During the CPAP trial, the median (range) arousal index of the spouses decreased from 21 (14-34) to 12 (4-27) (P < .01), and the spouses' median (range) sleep efficiency increased from 74% (56%-80%) to 87% (64%-95%) (P < .01). CONCLUSION: The elimination of snoring and OSA in these patients was associated with an improvement in the quality of their bed partners' sleep, as indicated by improved sleep efficiency and continuity, even when the spouses had been habitually exposed to snoring and OSA. Assuming that 480 minutes were spent in bed for sleep, a 13% improvement in sleep efficiency (i.e., from 74% to 87%) translates to an additional 62 minutes of sleep per night for the spouses of snorers with OSA.
Adult↗
Successful treatment of obstructive sleep apnea with use of nasal continuous positive airway pressure in three patients with mucosal hemangiomas of the oral cavity.
Cysts and benign tumors are uncommon causes of obstructive sleep apnea (OSA), and surgical removal is usually favored. In patients in whom an operation poses a high risk, however, nasal continuous positive airway pressure (CPAP) may prove beneficial. We describe three patients with hemangiomas of the oral cavity in whom polysomnography revealed moderate to severe OSA. In all three patients, nasal CPAP effectively decreased sleep-related disordered breathing events and dramatically improved their sleep. To our knowledge, this is the first report of OSA associated with hemangiomas involving the upper airway. Our experience suggests that nasal CPAP therapy is effective and well tolerated in such patients.
Female↗
Pergolide in the management of restless legs syndrome: an extended study.
Twenty patients with problematic restless legs syndrome (RLS) were treated with pergolide. Efficacy, dosage, side effects, and tolerance were analyzed. Fifteen patients continued treatment for a median study time of 2 years. Five patients discontinued treatment after a mean of 4.2 months. Pergolide resulted in complete or near complete control of symptoms in 45% and moderate control in 50% of patients studied. Levodopa-induced daytime augmentation resolved in all patients in whom it had been present. The mean total daily maintenance dose of pergolide was 0.23 mg. Forty percent required an additional afternoon dose. Side effects developed in 12 patients (60%) and necessitated discontinuation of treatment in five. Common side effects were nausea, dizziness, and insomnia. Daytime augmentation occurred in 27% of patients, but this was mild and usually easily controlled with a supplementary afternoon dose of pergolide. Tolerance did not develop. We conclude that pergolide is an effective second-line agent for RLS, especially following levodopa-induced daytime augmentation.
Adult↗
The effects of sleep on circulating catecholamines and aqueous flow in human subjects.
We measured the rate of aqueous flow and analysed its relation to the time of day, the state of wakefulness and the urinary excretion of catecholamines. Two groups of subjects were studied. One group comprised 20 normal subjects who were studied over two 22-hr periods. During one period, the subjects were permitted to sleep during their customary hours of sleep; during the other, they were not permitted to sleep, but remained active for all 22 hr. The other group comprised ten subjects with obstructive sleep apnea who were studied over a 22-hr period and slept during their customary hours of sleep but without the aid of any respiratory device. Aqueous flow was measured with fluorophotometry. Motion of the wrist was monitored by a seismograph (wrist Actigraph) and served as a surrogate of activity and wakefulness. Urinary catecholamine excretion was measured during different periods of the wake/sleep cycle. Both groups exhibited the normal nocturnal suppression of flow (59% lower compared to morning in the normal group; 56% lower compared to morning in the apneic group). During sleep deprivation, the rate of flow at night in normal subjects was 30% lower than during the morning (P < 0.001) and 60% higher than during sleep (P < 0.001). Lid closure during sleep deprivation had no effect on the results. Aqueous flow correlated with a 'catecholamine index', derived from the combined excretion of epinephrine and norepinephrine. Flow also correlated with an 'activity index', and 'sleep efficiency', indices derived from motion of the wrist. We conclude that the day-night difference of aqueous humor flow as measured by clearance of fluorescein from the human eye is driven partly by a factor that has a circadian rhythm and partly by a factor that depends on the activity of the subject. We hypothesize that these factors are the catecholamines, epinephrine and norepinephrine.
Adult↗
Effects of changes in central venous pressure on upper airway size in patients with obstructive sleep apnea.
Intraluminal airway pressure and pharyngeal muscle activity are widely recognized as major determinants of the size and collapsibility of the upper airway. In addition, changes in the volume or pressure of tissue surrounding the pharyngeal airway may significantly influence its size. The present study used fast computed tomography (CT) to determine the effects of changes in central venous pressure (CVP) on upper airway size. Ten awake male patients with obstructive sleep apnea (OSA) were studied. Scans were performed at functional residual capacity (FRC) and at the end of a tidal inspiration (VTei) under three conditions of CVP: (1) at baseline (CVP nl) with patients lying supine; (2) at decreased CVP (CVP-) by inflating blood pressure cuffs to 40 mm Hg on both legs; and (3) at increased CVP (CVP+) by elevating both legs to 33 degrees. At FRC, changes in CVP had no significant effect on either mean or minimum cross-sectional area (CSA) of the upper airway. In contrast, an analysis of variance (ANOVA) indicated that alterations in CVP were associated with changes in mean CSA (p = 0.03) and to a lesser extent in minimum CSA (p = 0.07) at VTei. With the legs elevated (CVP+), neither mean nor minimum CSA showed any significant change with tidal breathing. However, after leg-cuff inflation (CVP-), highly significant increases in both mean (163 +/- 22 to 218 +/- 19 mm2, p = 0.001) and minimum (48 +/- 8 to 85 +/- 12 mm2, p = 0.02) CSA were detected. Changes in mean and minimum CSA with tidal breathing at baseline (CVP nl) were intermediate. These results indicate that changes in CVP significantly alter the response of the upper airway to tidal breathing. They further suggest that increases in upper airway size with tidal breathing may be related to reduction in venous blood volume in pharyngeal and neck tissues as the generation of negative intrathoracic pressure during inspiration increases venous return to the chest.
Adult↗
Effects of body position on the upper airway of patients with obstructive sleep apnea.
Fast-CT scanning was used to study the effects of changes in body position on upper airway (UA) size and shape in 11 awake subjects with obstructive sleep apnea (OSA). Six patients with position (P)-dependent OSA were compared with five patients with nonposition (NP)-dependent OSA. Scans were repeated in the prone (PRN), right side (RS), and supine (SUP) body positions at both functional residual capacity and end-inspiratory tidal volume. Significant group, group by position, and borderline group by respiration effects were detected for minimum but not mean UA dimension data. Significant differences between groups were noted in minimum cross-sectional area and minimum lateral distance but not in minimum anteroposterior distance in the RS and SUP positions. Turning from the PRN to the RS or SUP position tended to decrease UA size in the NP group by decreasing the lateral distance, while the opposite effect was found in the P group. The results indicate that changes in body position during wakefulness affect the lateral but not the anteroposterior dimensions of the UA, and the UA behaves differently in patients with NP and P OSA in response to changes in body position.
Case-Control Studies↗
Acute effects of transdermal nicotine on sleep architecture, snoring, and sleep-disordered breathing in nonsmokers.
Previous research has suggested that nicotine may be therapeutically useful in the treatment of sleep-disordered breathing. The development of transdermal nicotine delivery systems has allowed us to test the overnight effectiveness of nicotine. Twenty nonsmoking subjects (10 men, 10 women) were recruited on the basis of a history of habitual snoring that was confirmed by overnight laboratory monitoring. Subjects were then randomized (double-blind crossover design) to receive either placebo or an active patch that delivers 11 mg of nicotine over a 24-h period. Patches were applied at 6 P.M. and removed at 6 A.M. the following morning, at which time venous blood was obtained for determination of serum nicotine concentrations. Polysomnography was performed using standard techniques to assess sleep architecture and sleep-disordered breathing. Snoring was monitored with a sound-level meter and quantitatively analyzed to determine the snoring index (SI) (number of snores per hour of sleep) and mean and maximum snoring intensities. The age of the subjects was 46.9 +/- 11.4 yr (mean +/- SD) and their mean body mass index (BMI) 33.3 +/- 4.6 kg/m2. A mean nicotine level was nondetectable with placebo and 7.8 +/- 2.3 ng/ml with wearing of an active patch. Nicotine decreased total sleep time (TST) by 33 min (p < or 0.01), sleep efficiency from 89.7 to 83.5% (p < or = 0.01), and percent rapid eye movement (REM) sleep from 18.8 to 15.1% (p < or = 0.01), and prolonged initial sleep latency (ISL) from 6.7 to 18.2 min (p < or = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
Administration, Cutaneous↗
Fast-computed tomographic evaluation of the effect of route of breathing on upper airway size and function in normal men.
Nasal obstruction is associated with increased sleep disordered breathing (SDB), even in normal subjects. This increase in SDB may result from narrowing of the orohypopharyngeal (OHP) or retroglossal segment of the upper airway (UA) due to retropositioning of the jaw and tongue base as the mouth is opened and route of breathing changed from nasal to oral. It is postulated that significant narrowing of the OHP occurs with oral breathing even in the awake state. To ascertain the effect of route of breathing on the UA, fast-CT was used to study the UA response to the route of breathing in 30 normal, awake men, with each subject breathing via the nasal and oral routes under the following conditions: end-inspiration during tidal breathing (VTei) and functional residual capacity (FRC). In the velopharyngeal (VP) or retropalatal segment of the UA, minimum (Amin) and mean (Amean) cross-sectional areas (CSA) decreased 49 +/- 11 percent and 16 +/- 6 percent, respectively, with oral compared with nasal breathing at FRC. In the OHP, Amin at FRC increased by 26 +/- 15 percent with oral compared with nasal breathing with no significant change in Amean. Similar changes in CSA of both the VP and OHP were observed at VTei. Genioglossal electromyographic (EMGgg) activity increased from 12 +/- 1 microV breathing nasally to 27 +/- 4 microV breathing orally at FRC. Although the CSA of the VP segment decreased with conversion from nasal to oral breathing, Amin of the OHP segment was unexpectedly observed to increase with oral breathing. The doubling of EMGgg activity with oral breathing suggests that active contraction of the genioglossus may function to increase the patency of the OHP segment during oral breathing in supine, awake, normal subjects.
Adult↗
Excessive daytime sleepiness, upper airway resistance, and nocturnal arousals.
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Airway Resistance↗
Relations between sleep stage, posture and effective nasal CPAP levels in OSA.
A retrospective analysis of positional data from 100 male patients with obstructive sleep apnea (OSA) was conducted to determine whether or not 1) the degree of positional dependency was similar in rapid eye movement (REM) compared to non-REM (NREM) sleep, 2) positional dependency correlated with effective levels of nasal continuous positive airway pressure (CPAP) and 3) patients with positional OSA preferentially avoided sleeping in the supine position. The apnea-hypopnea index (AHI) was scored separately for sleep state (NREM and REM) and for posture [off back (AHI-O) and on back (AHI-B)]. The ratio of AHI-O/AHI-B was used to define positional OSA as AHI-O/AHI-B less than or equal to 0.50 (P group) and nonpositional OSA as 0.50 less than AHI-O/AHI-B (NP group). A group of 31 patients who had sufficient sleep time in NREM and REM sleep in both sleep postures was selected. In this group 9 out of 22 subjects who showed positional dependency during NREM sleep became nonpositional during REM sleep (0.05 less than p less than 0.10). The mean effective nasal CPAP level was slightly, but significantly, lower in the P group than in the NP group (8.0 versus 9.1 cm H2O; p less than 0.05). In addition, a correlation between AHI and effective nasal CPAP levels was found (r = 0.491; p = 0.0001). The P group had less supine sleep time (SST) than the NP group (32% versus 45% of total sleep; p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)
Airway Resistance↗
Fast-computed tomography evaluation of age-related changes in upper airway structure and function in normal men.
The reasons for the increase prevalence of snoring and sleep-disordered breathing in elderly adults are not clear. We hypothesized that age-related reductions in upper airway (UA) size, increased UA collapsibility, and/or inadequate compensatory action of the UA dilator muscles were contributory factors. Fast-computed tomography (CT) was used to examine UA size at FRC and atmospheric pressure, as well as its collapsibility and distensibility in response to negative and positive UA pressures actively generated by the subjects at FRC. The electromyographic activity of the genlogiossal muscle group (EMGgg) was recorded to assess UA dilator muscle response. Thirty adult men with normal overnight polysomnography (mean AHI = 4 +/- 1/h) were studied, and three subgroups of 10 subjects each, young (20-39), middle-age (40-59), and old (60-79), were compared. Unexpectedly, minimal UA cross-sectional area (Amin) at FRC and atmospheric pressure was larger in the old group than in the young group (73 +/- 9 versus 49 +/- 7 mm2, p = 0.04). In response to negative UA pressures of -10 and -50 cm H2O, there were no significant age group differences in Amin, indicating that no age-related increase in UA collapsibility was present. Although no significant difference in tonic EMGgg activity at FRC and atmospheric pressure was detected between groups, the old group demonstrated greater EMGgg activity than did the younger age groups in response to negative UA pressure loading (p less than 0.05). This finding indicated increased compensatory UA dilator muscle activity in response to negative pressures in the older subjects.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Fast-CT evaluation of the effect of lung volume on upper airway size and function in normal men.
The present study was performed to evaluate the regional changes in pharyngeal cross-sectional area (CSA) that occur with changes in lung volume in normal men. Fast-CT and genioglossal electromyogram (EMGgg) were used to study upper airway (UA) size and dilator muscle activity at TLC, lung volume at end-tidal inspiration (VTei), FRC, and residual volume (RV) in 30 men with a mean age of 46 +/- 3 yr and no significant sleep-disordered breathing, mean AHI = 4 +/- 1 per hour. Compared with values at FRC, minimum CSA (Amin) increased 154 +/- 31% at TLC (p = 0.0001), 19 +/- 10% at VTei (p = 0.03), and there was a trend toward a decrease of 31 +/- 12% at RV (p = 0.07). Similar but smaller changes were observed in mean CSA (Amean), with an increase of 69 +/- 14% at TLC (p = 0.0001), 8 +/- 5% at VTei (p = 0.01), and a decrease of 17 +/- 7% at RV (p = 0.01). Both the velopharyngeal (VP) and orohypopharyngeal (OHP) segments of the UA increased in size with increasing lung volume. Both Amin and Amean of the OHP segment at TLC were larger (55 +/- 19 and 38 +/- 14%, respectively) than the respective measurements in the VP segment. EMGgg activity doubled from 12 +/- 1 microV at FRC to 25 +/- 1 microV at TLC (p = 0.006). There was no change in EMGgg with tidal ventilation or with exhalation to RV. Changes in CSA directly paralleled changes in lung volume in this group of normal awake nonobese men.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
The effects of transcutaneous electrical stimulation during wakefulness and sleep in patients with obstructive sleep apnea.
Upper airway (UA) collapse in obstructive sleep apnea (OSA) is considered in part to result from the decrease in UA dilator muscle tone that occurs during sleep. We hypothesized that augmentation of UA muscle function by transcutaneous electrical stimulation (TES) might function to enlarge UA size during wakefulness and/or prevent UA collapse during sleep in patients with OSA. Eight male patients with OSA were studied both awake and asleep, with TES administered to the submental region in two patients and to both the submental and subhyoid regions in six patients. Fast-CT scans obtained at FRC and end-inspiration (VTei) demonstrated increased UA size with tidal breathing, p less than or equal to 0.05. The active generation of -10 cm H2O pressure at FRC substantially decreased UA size, p less than or equal to 0.001. However, no changes in UA size were detected at either FRC or VTei with TES applied at 50 and 100% of the maximal tolerated intensity. The collapsibility of the UA in response to the generation of -10 cm H2O pressure was also unchanged by TES. In contrast to the lack of effect of TES on UA size, voluntary protrusion of the tongue increased cross-sectional area (CSA) of the orohypopharyngeal (OHP) segment of the UA, p less than 0.05, and to a lesser extent the CSA of the distal velopharyngeal segment, p = 0.06. When applied during sleep, TES failed to prevent or improve either sleep-disordered breathing or sleep architecture.(ABSTRACT TRUNCATED AT 250 WORDS)
Humans↗
Hypertension, cardiac arrhythmias, myocardial infarction, and stroke in relation to obstructive sleep apnea.
The cyclical changes in heart rate and systemic blood pressure that accompany apneic events are predominantly mediated by fluctuations in the activity of the autonomic nervous system. Increased vagal efferent parasympathetic activity is responsible for the cyclical reductions in heart rate during apnea. In contrast, the cyclical elevations in systemic blood pressure are believed to result from recurrent peripheral vasoconstriction mediated by repetitive activation of the sympathetic nervous system. Maximal activation and pressures coincide with apnea termination and brief arousal from sleep. These cyclical elevations in systemic pressure during sleep increase ventricular workload and, thereby, may contribute to the development of ventricular hypertrophy. Systemic hypertension is present during wakefulness in approximately 50% of patients with OSA. Although age and obesity are the predominant risk factors for diurnal hypertension, OSA probably makes an independent contribution in younger obese men. Sinus bradycardia, Mobitz type 1 second-degree heart block, and prolonged sinus arrest have all been documented in association with the apneic events. Increased ventricular ectopy has been observed with oxyhemoglobin desaturations below 60%. Myocardial ischemia, infarction, sudden death, and stroke all demonstrate similar circadian variations in time of onset. Peak frequencies occur between 6 AM and noon, generally within several hours of awakening. Although sleep is associated with decreased frequencies of these adverse cardiovascular events in the general population, evidence exists linking REM sleep to an increased risk of myocardial ischemia. In men who habitually snore, epidemiologic data have detected an increased risk for ischemic heart disease and stroke. Habitual snoring has also been associated with an increased risk of sudden death during sleep. In patients with clinically significant OSA, there is reasonable information indicating excessive mortality in the absence of treatment. This mortality is predominantly cardiovascular and tends to occur during sleep.
Arrhythmias, Cardiac↗
Evaluation of the upper airway in patients with obstructive sleep apnea.
Multiple methods have been used to study the structure and physiological behavior of the upper airway (UA) in patients with obstructive sleep apnea (OSA). Valuable information may be obtained from the physiologic measurement of pressure and resistance along the UA, as well as from imaging techniques that include: direct or fiberoptic visualization, cephalometric roentgenograms, fluoroscopy, acoustic reflection, computerized tomography, and magnetic resonance imaging. This review summarizes the information that each of these methods has contributed to our understanding of the UA. The results obtained with these different methodologies have generally been complementary with structural narrowing being identified in the majority of patients with OSA. This narrowing is usually focal and located in the velopharyngeal or retropalatal segment of the UA. This is also the predominant site of initial UA collapse. Although obesity with enlargement of soft tissue structures is considered the predominant mechanism leading to UA narrowing, abnormal craniofacial development on a genetic or developmental basis plays an important contributory role.
Airway Obstruction↗
Cardiopulmonary consequences of obstructive sleep apnea.
During sleep, oxygen consumption and systemic blood pressure decrease in normal subjects; during rapid eye movement sleep, irregular ventilation can be accompanied by brief periods of apnea. In patients with obstructive sleep apnea, alveolar ventilation during an apneic episode is immediately reduced to zero, and the metabolic demands for oxygen must be met from oxygen stores within the body. As the stores of oxygen within the lung are diminished, the rate of arterial oxyhemoglobin desaturation increases. The development of alveolar hypoventilation during wakefulness seems to be based on a balance between central ventilatory drives to breathe and mechanical loads placed on the respiratory system. Coexistent cardiopulmonary or neuromuscular disease in patients with obstructive sleep apnea contributes to the development of alveolar hypoventilation. During apneic episodes, the systemic blood pressure increases while the heart rate and cardiac output decrease. Both bradycardias and increased ventricular ectopic activity have been associated with these disordered breathing episodes. Because of the possibility of apnea-associated arrhythmias, patients with obstructive sleep apnea may be at increased risk for cardiovascular mortality. The influence of these recurrent nocturnal episodes of asphyxia on cardiovascular longevity needs further investigation.
Arrhythmias, Cardiac↗
Uvulopalatopharyngoplasty for treatment of obstructive sleep apnea.
Currently, uvulopalatopharyngoplasty (UPPP) is the most common surgical procedure used for the treatment of obstructive sleep apnea. Patients with clinically significant obstructive sleep apnea in whom medical treatment has failed or who are unwilling to comply with medical therapy are considered candidates for UPPP. The initial surgical results obtained in nonselected patients with obstructive sleep apnea were highly variable, approximately half of the patients experiencing more than a 50% reduction in the frequency of disordered breathing events postoperatively. Although differences in surgical technique likely account for some of the variability, preoperative differences in the site (or sites) of upper airway collapse are also thought to influence the surgical results. Because UPPP involves resection of the uvula, distal margin of the soft palate, palatine tonsils, and any excessive lateral pharyngeal tissue, patients with anatomic narrowing and collapse confined to the velopharyngeal or retropalatal region of the upper airway are considered optimal surgical candidates. Fiberoptic pharyngoscopy, cephalometric roentgenography, computed tomography, and somnofluoroscopy are procedures that can be used preoperatively to help select optimal candidates for UPPP. The results suggest that the success rate of UPPP can approach 66% with careful preoperative selection of patients.
Evaluation Studies as Topic↗