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Biomedical subjects

D Rodenstein

Publications and source records attributed to D Rodenstein.

At least 19 recordsLinked to original sources
PubMed2005

Nasal obstruction and its impact on sleep-related breathing disorders.

Upper airway patency is essential during sleep in order to avoid sleep-related breathing disorders (SRBD). Nasal obstruction may have a negative impact on sleep quality and must be considered to be a co-factor in the pathophysiology of SRBD. In this paper we will discuss the relation between nasal physiology at night and sleep quality and the possible mechanisms between nasal obstruction and obstructive sleep apnea-hypopnea syndrome (OSAS). We will review the effect of the relief of nasal obstruction (with nasal dilators, medication and/or surgery) on SRBD. Also an algorithm on the management of OSAS patients when nasal surgery is indicated will be proposed.

Continuous Positive Airway Pressure↗
PubMed2002

Supramaximal flow in asthmatic patients.

In normal subjects supramaximal flows (SF) are known to be correlated with flow limitation. To further understand the mechanisms involved in SF this correlation and the influence of salbutamol and methacholine administration on SF have been investigated in asthmatic subjects. Protocol A involved obtaining basal maximal expiratory flow/volume curves and interrupted curves through a fast valve from 36 asthmatic patients. Maximal flow at 50% of forced vital capacity (V'max50) increase (deltaV'max50) was compared between basal curves and envelope curves passing through SF peaks obtained after each interruption. Protocol B involved the study of 33 asthmatic patients after salbutamol administration and 12 asthmatic patients after methacholine challenge. DeltaV'max50 between basal versus interrupted curves were analysed (deltaV'max50B). Similar procedures were performed after salbutamol (deltaV'max50S) and after methacholine administration (deltaV'max50M). A significant negative correlation between forced expiratory volume in one second and deltaV'max50 was observed. SF decreased significantly after salbutamol administration and increased significantly after methacholine. The results of this study suggest that in asthmatic patients participation of "pendelluft" in SF increases as airflow limitation increases.

Adult↗
PubMed2002

Clinical presentation and definitions of sleep-related breathing disorders.

The sleep disordered breathing (SDB) patients need to be monitored for sleep and breathing during sleep. However there is no consensus about the definitions of the most common features observed during the night. Although apnea is usually defined as a cessation of airflow lasting more than 10 seconds, the definitions of hypopnea differ in the literature with respect to the amount of reduction of airflow and to the drop in oxygen desaturation. Variations in the technique of monitoring airflow and ventilary effort can cause variation in the detection of SDB events. We discuss in this paper the standard definitions of respiratory events as observed during the night and the elements of diagnosis obtained with the polysomnographic examination for the SDB patients.

Airway Resistance↗
PubMed2000

Obstructive sleep apnea syndrome after reconstructive laryngectomy for glottic carcinoma.

Obstructive sleep apnea syndrome (OSAS) is characterized by repetitive episodes of partial or complete obstruction of the upper airway during sleep. The obstruction predominantly occurs along the pharyngeal airway but other sites of obstruction have occasionally been described. We report our experience with three patients suffering from OSAS suspected to be of laryngeal origin. OSAS developed after reconstructive laryngectomy for glottic carcinoma and upper airway obstruction seemed to be located in the reconstructed laryngeal area. The three patients were given nCPAP (nasal-continuous positive airway pressure) treatment associated with peroral endoscopic CO2 laser vaporization of the laryngeal edema. After CO2 laser treatment, one patient was able to stop nCPAP treatment. The other two have remained on nCPAP therapy. OSAS may arise in the post-operative period of reconstructive laryngectomy for glottic carcinoma and can be managed by CO2 laser vaporization (laryngeal edema in the reconstructed area) in association with nCPAP treatment.

Aged↗
PubMed2000

[Diagnosis of nocturnal respiratory disorders. Review of portable screening systems. Analysis and critique of different polysomnographic signals].

Polysomnography in an attended hospital laboratory setting is the gold standard for the diagnosis of sleep-related breathing disorders. However, this method is expensive and waiting lists are long. Portable recording devices that can be used at home have been recently developed to improve upon the problems of polysomnography. We review the recent portable devices validated by polysomnography and discuss their precise role in the assessment of sleep-related respiratory disorders.

Equipment Design↗
PubMed1999

Effective compliance during the first 3 months of continuous positive airway pressure. A European prospective study of 121 patients.

Effective compliance (time spent at the effective pressure) with nasal CPAP in obstructive sleep apnea has been reported to be poor. The aim of our study was to evaluate effective compliance in a large European multicenter study. One hundred twenty-one consecutive newly treated patients (initial apnea-hypopnea index [AHI] = 62.0 +/- 29. 5/h, AHI under CPAP = 6.4 +/- 8.1/h, CPAP pressure = 8.7 +/- 2.6 cm H(2)O, BMI = 33.1 +/- 6.8 kg/m(2)) were randomly allocated to a group with (MC(+)) (n = 58) or without (MC(-)) (n = 63) a control unit measuring effective compliance at 1, 2, and 3 mo, which was compared with the built-in time counter data. MC(+) data were 94 +/- 10, 98 +/- 5, and 96 +/- 9% of counter data at 1, 2, and 3 mo, respectively. Using criteria of regular use already reported in the literature (at least 4 h of nCPAP per day of use and nCPAP administered more than 70% of the days) we found 77, 82, and 79% compliant patients at 1, 2, and 3 mo, respectively, 79% of the patients meeting these criteria each month. Although there were no pulmonary functions or polysomnographic differences between the two subgroups, the compliant patients did report a greater improvement in minor symptoms. We found a close correlation between effective use of CPAP and the machine run time. The main result of our study was a higher effective compliance than previously reported, approximately 80% of the patients being regular users versus 46% in a previously published study. This may result from different technical and medical follow-up.

Female↗
PubMed1998

[Diagnosis of nocturnal respiratory disorders. Review of portable monitoring devices. Analysis and evaluation of different polysomnography signals].

Polysomnography in an attended hospital laboratory setting is the gold standard for the diagnosis of sleep-related breathing disorders. However, this method is expensive and waiting lists are long. Portable recording devices that can be used at home have been recently developed to improve upon the problems of polysomnography. We review the recent portable devices validated by polysomnography and discuss their precise role in the assessment of sleep-related respiratory disorders.

Equipment Design↗
PubMed1996

Relationship between supramaximal flows and flow-limiting mechanisms.

The aim of this study was to evaluate the relationship between supramaximal flows (SF) and indices of airway mechanics. We studied 26 asymptomatic young subjects (13 smokers, mean +/- SD 15.9 +/- 6.6 pack-years. Subjects performed maximal expiratory flow-volume (MEFV) curves, according to the American Thoracic Society (ATS) criteria, on a rolling-seal spirometer and then repeated them through a specially devised valve, which occluded the mouthpiece either 3 or 6 times.s-1 with a ratio of open:closed time of 3:1. Envelope MEFV curves for 3 and 6 Hz occlusions were constructed passing through the SF obtained after each occlusion, and the increment in flow at 50% of vital capacity was measured with respect to the basal curve (delta V' max50). We found that the delta V' max50 at 3 and 6 Hz correlated to the baseline forced mid-expiratory flow (FEF25-75) in % of predicted value (r = -0.73 and r = -0.55, respectively). our results suggest that inhomogeneities within the lung are an important mechanism in the occurrence of supramaximal flow in normal subjects.

Adult↗
PubMed1996

Acoustic analysis of snoring sound in patients with simple snoring and obstructive sleep apnoea.

Snoring, a symptom which may indicate the presence of the obstructive sleep apnoea syndrome (OSA), is also common in the general population. Recent studies have suggested that the acoustic characteristics of snoring sound may differ between simple snorers and OSA patients. We have studied a small number of patients with simple snoring and OSA, analysing the acoustic characteristics of the snoring sound. Seventeen male patients, 10 with OSA (apnoea/hypopnoea index (AHI) 26.2 events x h(-1)) and seven simple snorers (AHI 3.8 events x h(-1)), were studied. Full night polysomnography was performed and the snoring sound power spectrum was analysed. Spectral analysis of snoring sound showed the existence of two different patterns. The first pattern was characterized by the presence of a fundamental frequency and several harmonics. The second pattern was characterized by a low frequency peak with the sound energy scattered on a narrower band of frequencies, but without clearly identified harmonics. The seven simple snorers and two of the 10 patients with OSA (AIH 13 and 14 events x h(-1), respectively) showed the first pattern. The rest of the OSA patients showed the second pattern. The peak frequency of snoring was significantly lower in OSA patients, with all but one OSA patient and only one simple snorer showing a peak frequency below 150 Hz. A significant negative correlation was found between AHI and peak and mean frequencies of the snoring power spectrum (p<0.0016 and p<0.0089, respectively). In conclusion, this study demonstrates significant differences in the sound power spectrum of snoring sound between subjects with simple snoring and obstructive sleep apnoea patients.

Acoustics↗
PubMed1996

[Non-invasive mechanical ventilation in intensive care].

Non-invasive mechanical ventilation is useful in order to delay or avoid endotracheal intubation. Continuous positive airway pressure (CPAP) is helpful for patients with decreased lung compliance, airways obstruction due to vocal cord paralysis or tracheobronchomalacia, presence of auto-PEEP (positive end-expiratory pressure) and as a weaning method. Non-invasive intermittent positive pressure ventilation (IPPV) is not very different from conventional mechanical ventilation except for the absence of an endotracheal tube. It is specially useful in patients with neuromuscular diseases or central hypoventilation. It has been also helpful for patients with decrease of lung compliance or COPD and as a weaning procedure. It may be applied with or without PEEP and by means of a bi-level IPPV system. All of these methods require cooperative patients and by means of a bi-level IPPV system. All of these methods require cooperative patients and they do not allow an adequate management of increased respiratory secretions. Non-invasive mechanical ventilation has the advantages of not showing complications associated to endotraqueal intubation and may be performed by means of less expensive equipment.

Critical Care↗
PubMed1993

Acoustic analysis of vowel emission in obstructive sleep apnea.

UNLABELLED: We studied vocalization in 18 men with obstructive sleep apnea syndrome (OSAS) (age, 49 [7.5] years; body mass index [BMI] 33.6 [7.6]) and 10 normal men as a control group (age, 46.7 [6.2] years; BMI 24.6 [2.2]). Polysomnographic data for patients with OSAS were as follows: total sleep time (TST), 387.5 [27.9] min; awake, 17.6 (12.6% TST); stage 1, 19.8 (18.7 percent TST); stage 2, 54.8 (23.2 percent TST); stage 3 and 4, 1.5 (0.3 percent TST); and stage REM, 4.2 (1.7 percent TST). Apnea hypopnea index (AHI) was 43.0 (18.2) and lowest O2 saturation was 73.6 (11.4). We recorded the following sounds in all subjects: /a/ as in "father"; /e/ as in "get"; /i/ as in "see"; /o/ as in "go"; /u/ as in "too." Three maneuvers for each vowel sound were taken for analysis. Signals were digitized at 10,000 Hz. Fast Fourier transformation was applied to segments of 512 points of each utterance corresponding to the vowel sound. The following parameters were obtained: maximum frequency of harmonics, mean frequency of harmonics, and the number of harmonics. RESULTS: There were significant differences between both groups in the maximum frequency of harmonics of /i/ and /e/ vowels. (For /i/: 2,650 [672] Hz controls; 425 [71.2] Hz OSAS. For /e/: 2,605 [772.3] Hz controls; 1,250.0 [828.4] OSAS). The number of harmonics for /i/ vowel was 4.5 (1.2) for controls as compared with 2.7 (1) Hz for OSAS. CONCLUSIONS: Vocalization in patients with OSAS is different from normal subjects. Vowel /i/ can distinguish these patients from normal subjects.

Body Mass Index↗