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V Hoffstein

Publications and source records attributed to V Hoffstein.

At least 19 recordsLinked to original sources
PubMed1999

Does snoring contribute to presbycusis?

It is well known that hearing acuity decreases with age. The precise mechanism responsible for this phenomenon, called presbycusis, is unknown. One hypothesis advanced to explain this loss of acuity implicates chronic exposure to snoring noise. Consequently, the purpose of this study was to investigate whether snoring is associated with hearing loss. We examined 219 patients (63 women and 156 men) referred to our sleep disorders center. All of the patients underwent nocturnal polysomnography with measurements of snoring, as well as standard audiometry (i.e., measurement of hearing thresholds at 250 Hz, 500 Hz, 1 kHz, 2 kHz, 3 kHz, 4 kHz, 6 kHz, and 8 kHz). Snoring was quantified by measuring three parameters: snoring index (SI = number of snores/h of sleep), average nocturnal sound intensity (dBav), and maximum nocturnal sound intensity (dBmax). We used simple correlation analysis to investigate the relationship between snoring and hearing thresholds; multiple linear regression analysis to determine individual contributions of age, sex, and snoring to the variability in hearing thresholds; and comparison tests to determine whether mild snorers had less hearing impairment than severe snorers. None of these statistical tests demonstrated that snoring was a significant determinant of hearing. We conclude that snoring is not associated with hearing loss and is therefore unlikely to account for presbycusis.

Adolescent↗
PubMed1997

Comparison of direct and indirect measurements of respiratory airflow: implications for hypopneas.

The purpose of this study was to compare indirect methods for measuring respiratory airflow, such as temperature difference between inspired and expired air, thoracoabdominal movements, and nasal respiratory-airflow pressures-with a more direct measurement of minute ventilation using a head-out body plethysmograph. Measurements were obtained in healthy, awake, seated subjects during sequences of different levels of voluntary hypoventilations at 20 breaths/minute and analyzed to determine how well different methods could identify hypopneas (defined as reduction in minute ventilation by 50% or more). The results varied widely between different methods. Sensitivities ranged from 0 to 1, specificity ranged from 0.33 to 1, positive predictive values (PPV) ranged from 0 to 0.73, negative predictive values (NPV) ranged from 0.68 to 0.93. Cohen's kappa varied between 0 and 0.65 The poorest agreement was for the thermistor method, and the best agreement was obtained when a combination of thoraco-abdominal movements and nasal respiratory-airflow pressure was employed (sensitivity = 0.86, specificity = 0.83, PPV = 0.71, NPV = 0.92, Cohen's kappa = 0.65). We conclude that none of the indirect methods investigated, individually or in combination, proved adequate for identification of voluntary hypopneas in awake individuals.

Humans↗
PubMed1997

Arousals and nocturnal respiration in symptomatic snorers and nonsnorers.

The purpose of the present investigation was to examine the relationship among upper airway resistance, snoring, and arousals, all measured simultaneously, in nonapneic snorers complaining of excessive daytime sleepiness (EDS). To accomplish this task, we selected a group of nine nonapneic snorers who presented because of snoring, EDS, tiredness, or fatigue. Ten healthy, alert, nonapneic, nonsnoring subjects recruited from among the hospital personnel acted as a comparison group. All subjects had nocturnal polysomnography, which included measurements of snoring, nasal and pharyngeal airway pressure, esophageal pressure, and total respiratory flow. Each polysomnogram was analyzed to identify all arousals and all respiratory events, i.e. apneas, hypopneas, and periods of increased upper airway resistance. Each arousal was examined to determine whether it was associated with a respiratory event, and each respiratory event was examined to determine whether it was associated with an arousal. The results were compared between snorers and nonsnorers. There was no significant difference between the two groups in the total sleep time (182+/-61 minutes in controls vs. 188+/-50 minutes in patients) or the total number of arousals per hour of sleep (24+/-12 in controls vs. 28+/-10 in snorers). However, the distribution of arousals, i.e. electroencephalogram (EEG) vs. respiratory, was different in snorers and nonsnorers. In snorers 55% of arousals were respiratory, whereas in nonsnorers only 17% of arousals were associated with respiratory events. Not unexpectedly, the snorers had significantly more respiratory events during the night (512) than controls (112). However, the relative proportion of these events that was accompanied by arousals was similar in both groups. We conclude that the difference in daytime function between symptomatic snorers and asymptomatic nonsnorers is unlikely to be due strictly to the number of arousals during the night; however, it is possible that respiratory and EEG arousals have different impacts on daytime performance, which may explain the difference in daytime function between our two groups.

Adult↗
PubMed1997

Is atelectasis following aortocoronary bypass related to temperature?

OBJECTIVE: To determine the frequency of acute postoperative atelectasis in patients undergoing aortocoronary bypass with either normothermic (warm) or hypothermic (cold) technique. DESIGN: Prospective, randomized study comparing two groups. SETTING: University-affiliated hospital. PATIENTS: Three hundred thirty-one patients (166 cold and 165 warm) undergoing isolated aortocoronary bypass. MEASUREMENTS: Chest radiographs were obtained preoperatively, on the day of surgery, and subsequently as clinically indicated until discharge from the hospital. Radiologist (blinded to the patient allocation into warm or cold group) scored the atelectasis from 0 to 3 based on its severity. Regression analysis was used to determine if there was any difference in the atelectasis scores between the two groups. RESULTS: Mean daily postoperative atelectasis scores were not different between the cold and warm groups. The number of patients requiring chest radiographs was similar in both groups. The percent of patients with abnormal chest radiographs was similar in both groups. CONCLUSION: The temperature of cardioplegia has no effect on the development of atelectasis following aortocoronary bypass, and therefore temperature-related cold injury is not a major cause of atelectasis following this type of surgery.

Body Temperature↗
PubMed1996

How and why should we stabilize the upper airway?

This review focuses on the evidence for upper airway instability during sleep and on the methods used to correct this instability. Upper airway patency during sleep is determined by the balance between the forces tending to constrict the pharynx (i.e. negative suction force generated by the diaphragm) and those tending to dilate in the pharynx (i.e. force acting on the tongue, soft palate and pharyngeal dilator muscles). The evidence for reduction in genioglossus activity and tensor palatini activity, failure of compensatory mechanisms to maintain these activities, and increase in upper airway resistance during sleep in reviewed. Coupled with abnormal pharyngeal anatomy to start with, the above events lead to abnormal pharyngeal function and cause repetitive episodes of airway occlusion, that is, sleep apnea. It is concluded that abnormal airway function in sleep apnea is a diffuse, rather than a localized process, that may involve the entire airway from the nasopharynx to the larynx. Methods to improve abnormal pharyngeal anatomy and pharyngeal function, such as nasal continuous positive airway pressure (CPAP), oral appliances, posture, weight loss, medications, and surgery are discussed. Given the pathophysiology of sleep apnea, that is, diffuse abnormality of the upper airway, it is reasonable to expect that only those approaches that exert a beneficial effect on the entire upper airway, as opposed to the approaches that modify only a short segment of it, may be expected to be of benefit in treatment of sleep apnea.

Airway Obstruction↗
PubMed1996

Postural changes in respiratory airflow pressure and resistance in nasal, hypopharyngeal, and pharyngeal airway in normal subjects.

We investigated the effect of posture on nasal and pharyngeal resistance in 12 healthy subjects studied during wakefulness. Airway pressure and airflow were measured with subjects seated and in dorsal and left lateral recumbency, during inspiration and expiration. We found that pharyngeal resistance was approximately four to six times lower than the nasal resistance. Only pharyngeal resistance was significantly increased upon assumption of a supine posture, from 0.02 +/- 0.01 Pa/mL per second when seated to 0.06 +/- 0.05 Pa/mL per second in dorsal recumbency and to 0.05 +/- 0.04 Pa/mL per second in left lateral recumbency. Mean nasal and pharyngeal resistances doubled upon assumption of a supine posture, but this difference was not statistically significant. There was no significant difference in pharyngeal resistance between inspiration and expiration. Finally, there was a strong linear relationship between pharyngeal pressure and pharyngeal resistance (r = .98, p<.0001). We concluded that in normal awake subjects 1) pharyngeal resistance increases with assumption of a supine posture, 2) the walls of the pharynx are not compliant enough to alter their resistance in response to inspiratory and expiratory pressure changes, and 3) it may be possible to infer pharyngeal resistance from measurements of pressure alone, without measurement of airflow.

Adult↗
PubMed1996

Snoring.

Explore the source record for details and available documents.

Humans↗
PubMed1996

Tracheobronchial constriction in asthmatics induced by isocapnic hyperventilation with dry cold air.

Although it is well known that isocapnic hyperventilation (IHV) with dry cold air produces airway constriction in asthmatic subjects, the site of airway narrowing is nuclear. To address this issue, we have quantified the tracheal and bronchial response to IHV with dry cold air in 15 patients with mild asthma and 7 healthy control subjects. We employed the acoustic reflection technique to evaluate changes in airway cross-sectional areas caused by IHV with dry cold air. Airway areas were measured during tidal breathing before and 5 to 10, 30, 60, and 90 min following cold air challenge. For analysis purposes, airway areas were divided into three anatomic segments: extrathoracic tracheal segment, intrathoracic tracheal segment, and main bronchial segment. These segments were assessed at a fixed volume below total lung capacity. Maximal and partial expiratory flow-volume curves were also obtained before each set of area measurements. In normal subjects, IHV with dry cold air caused no significant changes in FEV1, flow at 30% of the vital capacity in the partial curve (V30p), or airway areas. In asthmatics, at 5 to 10 min after challenge, we found that FEV1 decreased by 22 +/- 5% (mean +/- SEM) (p < 0.0001), V30p by 33 +/- 8% (p < 0.003), intrathoracic tracheal area by 10.7% +/- 2% (p < 0.03), and main bronchial area by 14 +/- 3% (p < 0.003). At 30 min, tracheal and main bronchial areas were returned to baseline levels; however, FEV1 and V30p were still significantly decreased, by 13 +/- 3% and 16 +/- 4%, respectively. We conclude that in asthmatics, IHV with dry cold air causes both tracheal and bronchial constriction, and that recovery seems to occur first in the central airways.

Acoustics↗
PubMed1996

Is snoring dangerous to your health?

The purpose of this commentary is to review the evidence linking simple snoring with hypertension and cardiovascular and cerebrovascular disease. This has been a topic of numerous investigations with seemingly divergent results, mainly because of the differences in methodology employed in various studies, such as inclusion of confounding factors, type of population examined, methods of measurements and analysis, etc. Nevertheless, despite these limitations, a review of 19 studies examining the association between snoring and hypertension clearly shows that in the majority of them (14 studies) snoring was not found to be an independent risk factor. An association between snoring and cardiovascular and cerebrovascular disease is somewhat more difficult to assess. Analysis of 15 recent studies dealing with this issue shows that 9 of them concluded that snoring is a risk factor for vascular disease, whereas 6 studies reached the opposite conclusion. However, a detailed review of the studies showing positive association between snoring and vascular disease indicates that in some of them unsuspected sleep apnea may have accounted for this increased risk. In addition, these studies exhibit a number of inconsistencies that raise doubts as to the true validity of association between snoring and vascular disease. Finally, it does not seem biologically plausible that snoring should be a risk factor for cardiovascular and cerebrovascular disease without also being a risk factor for hypertension. Consequently, based on the available information, one cannot conclude that snoring is an independent risk factor for such adverse vascular complications as hypertension and cardiovascular and cerebrovascular disease.

Cardiovascular Diseases↗
PubMed1996

Comparing perceptions and measurements of snoring.

The difficulty in measuring and quantifying snoring using objective criteria is that snoring is first and foremost of a subjective perception by a listener. To test the subjective perception of snoring and to compare it with objective measurements, we studied 25 patients referred to our laboratory because of snoring. All had full nocturnal polysomnography including measurements of snoring. Snoring sounds were recorded on paper and simultaneously stored on audiotape. The technologist scoring the polysomnogram counted the number of snores during a 20-minute segment. Two other technologists, unaware of the objective snoring count, listened to the audiotape and also counted the number of events that they perceived as snores. In 11 of 25 patients there was good agreement (within 25%) between the two listeners and the objective snore count. In another 7 of 25 patients there was good agreement between the listeners, but the objective snore count differed > 25%. In the last group of seven of 25 patients the difference in subjective snore counts perceived by both listeners was > 25%. The agreement between both listeners in judging snoring severity was moderate (weighted Cohen's kappa (w) = 0.49). We conclude that perception of snoring is highly subjective. We speculate that investigations studying consequences and treatment of snoring must employ either more sophisticated properly validated methods to measure snoring or alternatively resort to measurements of the underlying physiological abnormalities responsible for snoring, such as elevations in upper airway resistance.

Adult↗
PubMed1995

Snoring and arousals: a retrospective analysis.

The purpose of this retrospective analysis was to search for possible associations between snoring and arousals. We searched our data base containing more than 2,000 records and selected only patients who 1) had objective measurements of snoring, 2) were not taking sedating medication, 3) did not have sleep apnea (apnea/ hypopnea index < 10) and 4) did not have periodic leg movements (myoclonus index < 5). This procedure left 367 patients available for analysis. We hypothesized that arousals observed in these patients were associated with snoring, and we performed univariate and multivariate regression analysis with arousals as the dependent variable, and age, body mass index, snoring, maximum nocturnal sound intensity and nocturnal oxygen saturation as the independent variables. The results showed that only snoring and mean nocturnal oxygen saturation were significant (p < 0.05) but weak determinants of arousals, accounting for only 7% of their variance. To examine whether snorers have more arousals than non-snorers, we compared a control group of non-snorers (< 50 snores/hour of sleep), with a group of heavy snorers (> 400 snores/hour of sleep). We found that the arousal index was significantly but weakly higher in snorers than non-snorers [mean +/- standard deviation (SD) = 14 +/- 8 vs. 10 +/- 6, p < 0.002]. Conversely, patients within the highest arousal quartile snored significantly more than those within the lowest quartile (snoring index 293 +/- 292 vs. 179 +/- 282, p < 0.008, respectively). We conclude that despite the limitations of this retrospective analysis, there appears to be an association between snoring and arousals, warranting further, properly designed prospective studies.

Adolescent↗
PubMed1995

Diagnosis of obstructive sleep apnea using a portable transducer catheter.

As an initial step in simplifying the diagnosis of sleep apnea with a view toward using portable equipment in the home setting, we examined the efficacy of a portable transducer catheter that measures intrathoracic pressure. This catheter, connected to a miniature data-logger, can be introduced nasally into the airway, and the data so collected can be acquired, stored, and analyzed off-line. We tested this catheter against standard nocturnal polysomnography in 10 patients suffering from obstructive sleep apnea. We found that by using a combination of the raw pressure signal and an envelope pressure signal, we accurately identified apneas and hypopneas, and classified them as obstructive, central, and mixed. For the 10 subjects studied, the polysomnographic apnea/hypopnea index was 34 + 30, versus 32 + 28 obtained by analysis of the pressure tracings. Analysis of 200 respiratory events identified one-by-one from polysomnograms and pressure tracings revealed close correspondence between the two methods. The average duration of apneas was 22.1 + 6.7 s as measured by polysomnography, versus 21.9 + 6.6 s as measured from pressure tracings. Furthermore, there was excellent agreement between the two methods (kappa = 0.89, 95% confidence limits = 0.84 to 0.94). We conclude that our technique for identifying apnea based on measurements of intrathoracic pressure using a thin, portable transducer catheter is a promising method for simplifying the diagnosis of this disorder.

Adult↗
PubMed1995

Acoustic rhinometry in the evaluation of nasal obstruction.

Acoustic rhinometry (AR) is a recently developed objective technique for assessment of geometry of the nasal cavity. The technique is based on the analysis of sound waves reflected from the nasal cavities. It measures cross-sectional areas and nasal volume (NV). To obtain dependable assessments of nasal resistance by rhinomanometry or cross-sectional area measurements by AR, it is essential that the structural relations of the compliant vestibular region remain undisturbed by the measuring apparatus. The use of nozzles in making these measurements carries a great risk of direct distortion of the nasal valve. We used a nasal adapter that does not invade the nasal cavity and a chin support that stabilizes the head. In 51 healthy nasal cavities, the average minimum cross-sectional area (MCA) was 0.62 cm2 at 2.35 cm from the nostril and 0.67 cm2 at 2 cm from the nostril, respectively, before and after topical decongestion of the nasal mucosa. The MCA and NV findings in this group were significantly higher than MCA and NV (P < 0.001) in people with structural or mucosal abnormalities before mucosal decongestion. After mucosal decongestion, the MCA and NV were significantly higher in healthy nasal cavities than in nasal cavities with structural abnormalities (P < 0.001) but were not higher than nasal cavities with mucosal abnormalities (MCA, P = 0.05; NV, P = 0.06). A nozzle was applied in 20 healthy nasal cavities after mucosal decongestion, and a significantly higher MCA was found compared to measurements made with the nasal adapter (P = 0.02). We conclude that the nasal adapter, which does not invade the nasal cavities, avoids the distortion of the nasal valve and gives more accurate results.

Acoustics↗
PubMed1995

Snoring and nocturnal oxygenation. Is there a relationship?

OBJECTIVE: To test the hypothesis that snoring, independently of sleep apnea, is a significant determinant of nocturnal oxygen saturation. DESIGN: Prospective study. SETTING: Sleep disorders clinic, university teaching hospital. PATIENTS: Six hundred twenty-five nonapneic snorers referred to the clinic. METHODS: Nocturnal polysomnography, which included objective and simultaneous measurement of snoring and oxygen saturation, was performed in all patients. Pulmonary function tests and smoking history were also obtained. RESULTS: Multiple stepwise linear regression analysis demonstrated that age, body mass index, and pulmonary function were the most important determinants of nocturnal oxygen saturation, accounting for 20 to 30% of its variability. Snoring was a significant, although weak (partial r2 = 0.073, p < 0.001) determinant of lowest, but not mean, nocturnal oxygen saturation. When mild snorers were matched one-for-one for body mass index to a group of severe snorers, only the lowest, not the mean, nocturnal oxygen saturation was significantly different between the groups. CONCLUSIONS: Snoring is not associated with sustained nocturnal hypoxemia, but it is weakly related to lowest nocturnal oxygen saturation.

Adult↗
PubMed1995

Pharyngeal airflow during sleep.

This study was conducted to investigate the effects of sleep and nasal resistance on pharyngeal airflow in a group of healthy male adults without complaint of habitual snoring. Twelve subjects aged 21 to 60 years were studied in a sleep laboratory during exclusive nasal breathing. Nasal and pharyngeal airflow variables were measured concomitantly at different stages of sleep. Awake pharyngeal resistance averaged 0.02-0.03 Pa/cm3/s in recumbency. In stage 2 sleep and quiet breathing resistance increased by a factor of 3-4 and by a factor of 7-8 during snoring. Increased nasal loading did not increase pharyngeal resistance further or induce snoring. Mostly, increased pharyngeal resistances were of similar magnitude in both phases of respiration, but in a few instances inspiratory resistance exceeded that in expiration, and in a similar number the reverse was found. Overall, compliance of the pharyngeal airway was not a prominent feature in this group of subjects. The relationship between transpharyngeal pressure and resistance should be studied further in order to simplify future studies of airflow during sleep.

Adult↗