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Biomedical subjects

D O Rodenstein

Publications and source records attributed to D O Rodenstein.

At least 37 records · Page 2Linked to original sources
PubMed1999

Tracheobronchial foreign bodies: presentation and management in children and adults.

STUDY OBJECTIVES: To compare the clinical and management aspects of tracheobronchial aspirated foreign body (AFB) removal in children and adults; to assess the influence of the operator's experience on the outcome of the procedure. DESIGN: A retrospective review of a 20-year experience (from 1976 to 1996). SETTING: A 900-bed university hospital. PATIENTS: Eighty-four children up to 8 years old (the child group) and 28 adult patients (the adult group). RESULTS: The peak incidence of foreign body aspiration occurred during the second year of life in the child group and during the sixth decade in the adult group. The symptoms at presentation were similar in both age groups, but the diagnosis was significantly delayed in the adults. The AFBs were lodged preferentially in the right bronchial tree only in the adults; a central location was predominant (but not at all exclusive) in the children. Atelectasis was more common in the adults, and air trapping was more common in the children. The most frequent procedure was rigid bronchoscopy; when a flexible bronchoscope was used, it was always in the adult patients. When the operator was less experienced, a failed first attempt at bronchoscopy and the need for a second procedure were significantly more frequent. CONCLUSIONS: At presentation, the symptoms seen with AFBs do not differ according to the age of the patient; however, the delay to diagnosis, the location of the AFBs, and the radiographic images differ between child and adult populations. The removal of AFBs in patients of all ages can be performed by the same operators. Because the outcome associated with these procedures improves when the operator is experienced, the removal of AFBs should be performed in medical centers that are capable of acquiring and maintaining the necessary expertise.

Adolescent↗
PubMed1998

Effects of Breathe Right on snoring: a polysomnographic study.

The nasal vestibule is a major site of resistance to airflow in healthy subjects. A high nasal resistance may increase snoring. Activation of the alae nasi and alar retraction reduce resistance to airflow and improve ventilation. The Breathe Right (BR) device has been proposed to reduce or eliminate snoring by improving nasal breathing. We assessed the efficacy of BR on sleep quality and snoring during 2 full-night polysomnographies, the first without and the second with BR. Ten non-apnoeic snorers were studied. Snoring was present during 22-98% of total sleep time during the control night. Ear-nose-throat examination disclosed a nasal valve anomaly in five subjects, objectivated by anterior and posterior rhinomanometry. Quality of sleep and snoring were not influenced by BR, even when different sleep stages were analysed separately. No difference in snoring index was found between snorers with or without nasal valve anomaly. We conclude that BR is ineffective in relieving snoring in non-apnoeic snorers.

Adult↗
PubMed1998

Tracheal laceration and tension pneumomediastinum of spontaneous favorable outcome.

The case of a 75-year-old women with probable tracheal laceration and tension pneumomediastinum after intubation is reported. A dramatic reduction of tracheal caliber was observed during fiberoptic bronchoscopy. Despite severe dyspnea, the patient healed with conservative measures. We conclude that aggressive surgical treatment for tracheal laceration is not always necessary.

Aged↗
PubMed1998

Upper airway imaging in sleep apnoea syndrome: clinical applications.

Symptoms of habitual snoring and excessive daytime sleepiness are extremely common in the general population, and have poor predictive value in identifying patients with "true" sleep-related disordered breathing. The upper airways are the main anatomical site responsible for snoring and sleep apnoea; therefore, their examination via different means has been quite extensively assessed. Clinical examination may point to severe micrognathia or retrognathia, grossly hypertrophied tonsils, obvious macroglossia, and oedema and inflammation of the uvula and soft palate. A recently proposed model is promising, but has not been validated independently yet. Endoscopic investigations have been performed in awake as well as in sleeping patients, with the pharynx in relaxed or active states; their predictive value remains poor, both for diagnostic purposes and for identifying patients that may benefit from surgery. Radiographic and magnetic resonance imaging techniques have permitted a detailed understanding of the process of narrowing and collapse of the upper airways. Unfortunately, these techniques do not perform any better than the ones previously cited as clinically efficient tools for diagnosis in the population of patients suspected of sleep-related breathing disorders. In conclusion, clinical examination of the upper airways remains part of the clinical evaluation of patients suspected of sleep-related disordered breathing. Other imaging techniques may be used for research purposes, but do not yet seem to be worth including in the routine assessment of this population.

Airway Obstruction↗
PubMed1997

Effectiveness of controlled and spontaneous modes in nasal two-level positive pressure ventilation in awake and asleep normal subjects.

STUDY OBJECTIVES: The purpose of the present study was to compare in awake and asleep healthy subjects, under nasal intermittent positive pressure ventilation (nIPPV) with a two-level intermittent positive pressure device (two-level nIPPV), the efficacy of the controlled and spontaneous modes, and of different ventilator settings in increasing effective minute ventilation (VE). PARTICIPANTS: Eight healthy subjects were studied. SETTING: In the controlled mode, inspiratory positive airway pressure (IPAP) was kept at 15 cm H2O, expiratory positive airway pressure (EPAP) at 4 cm H2O, and the inspiratory/expiratory (I/E) time ratio at 1. The respirator frequencies were 17 and 25/min. In the spontaneous mode experiment, IPAP was started at 10 cm H2O and progressively increased to 15 and 20 cm H2O; EPAP was kept at 4 cm H2O. MEASUREMENTS AND RESULTS: We measured breath by breath the effective tidal volume (VT with respiratory inductive plethysmography), actual respiratory frequency (f), and effective VE. Using the controlled mode, effective VE was significantly higher on nIPPV than during spontaneous unassisted breathing, except in stage 2 nonrapid eye movement sleep at 17/min of frequency; increases in f from 17 to 25/min led to a significant decrease in VT reaching the lungs, during wakefulness and sleep; effective VE was higher at 25 than at 17/min of frequency only during sleep; periodic breathing was scarce and apneas were never observed. Using the spontaneous mode, with respect to awake spontaneous unassisted breathing, two-level nIPPV at 10 and 15 cm H2O of IPAP did not result in any significant increase in effective VE either in wakefulness or in sleep; only IPAP levels of 20 cm H2O resulted in a significant increase in effective VE; during sleep, effective VE was significantly lower than during wakefulness; respiratory rhythm instability (ie, periodic breathing and central apneas) were exceedingly common, and in some subjects extremely frequent, leading to surprisingly large falls in arterial oxygen saturation. CONCLUSIONS: It appears that two-level nIPPV should be used in the controlled mode rather than in the spontaneous mode, since it seems easier to increase effective VE with a lower IPAP at a high frequency than at a high pressure using the spontaneous mode. We suggest that the initial respirator settings in the controlled mode should be an f around 20/min, an I/E ratio of 1, 15 cm H2O of IPAP, and EPAP as low as possible.

Adult↗
PubMed1997

Compliance with nasal CPAP in obstructive sleep apnea patients.

Continuous positive airway pressure (CPAP) is currently the treatment of choice for the majority of patients with obstructive sleep apnea (OSA). After a CPAP trial, the initial acceptance rate is 70-80%. Patients who derive no subjective benefit from such a trial are poor candidates for home treatment with CPAP because they are likely to exhibit lower adherence and compliance rates. About 90% of OSA patients provided with CPAP apparatus will adhere to long-term CPAP treatment. Patients abandoning CPAP do so during the first few months of home therapy, a period during which close monitoring and support is warranted. Because of the strong correlation between the machine run time and effective pressure delivered at the nasal mask (90-95%), the time-counter of the CPAP device is sufficient to monitor compliance in clinical practice, allowing for early intervention in cases of suboptimal use. Longterm acceptors of CPAP display a satisfactory compliance (5-6.5 h of average daily use) which compares favourably with compliance with treatment in other chronic diseases. Lower acceptance and compliance rates have been reported in North America as compared to Europe. This could be related to cultural differences or different routines of prescription and follow-up.

Journal Article↗
PubMed1997

Nasal mask pressure waveform and inspiratory muscle rest during nasal assisted ventilation.

In mechanically ventilated patients, pressure and flow tracings can be used to assess respiratory pump muscle activity or rest. When the ventilation is delivered through an endotracheal tube, the respiratory system can be considered a one-compartment model, and activation of the respiratory muscles results in deformations and variability of the pressure tracings. This is also true when mechanical ventilation is delivered nasally. With intermittent positive-pressure ventilation delivered through a nasal mask (nIPPV), we have recently shown that the glottis can interfere with ventilation even in the absence of diaphragmatic surface electromyographic (EMG) activity. On the basis of our observations, we suggested that when mechanical ventilation is delivered through a nasal means of access, the respiratory system cannot be considered a one-compartment model. To confirm this hypothesis, we submitted one healthy subject to nIPPV while his glottis was continuously monitored through a fiberoptic bronchoscope and his diaphragmatic activity was monitored with a bipolar esophageal electrode. During wakefulness or sleep, we observed irregularities in the nasal mask pressure waveform, in nasal mask peak pressure, and in actual VT despite the absence of respiratory pump muscle activity. These irregularities were related to significant variations in the glottic width, rather than to the reappearance of transient phasic inspiratory muscle activity. We conclude that during nIPPV, deformations in the mask pressure waveform can be induced by variations in the glottic aperture without activation of the diaphragm. Thus, when mechanical ventilation does not bypass the glottis, the respiratory system does not behave like a one-compartment model, and EMG remains the only reliable technique for assessing diaphragmatic muscle activity.

Adult↗
PubMed1997

Residual effect of nCPAP applied for part of the night in patients with obstructive sleep apnoea.

The aim of the present study was to assess whether nasal continuous positive airway pressure (nCPAP) treatment, applied for only a few hours at the beginning of the night, has any residual effect on sleep and breathing during the ensuing hours of unassisted sleep in patients with obstructive sleep apnoea syndrome (OSAS). In 27 patients with newly-diagnosed OSAS, effective nCPAP was applied during the first part of the night and then withdrawn. Polysomnographic parameters after nCPAP withdrawal were compared with those of the corresponding part of the diagnostic polysomnography performed a few days or weeks before and with those of the first part of night on nCPAP. After 255+/-63 (mean+/-SD) min of sleep with normalization of sleep and breathing parameters under nCPAP, there was partial improvement of OSAS severity during the remaining 124+/-56 min of nocturnal sleep without treatment; mean oxygen saturation, desaturation index (equivalent to the apnoea/hypopnoea index) and movement arousal index all improved significantly with respect to the diagnostic night (p=0.001). This improvement was not accounted for by a change in sleep architecture. We conclude that there is an improvement in severity of obstructive sleep apnoea syndrome after only 4 h of nasal continuous positive airway pressure. This carryover effect could explain why a number of patients with obstructive sleep apnoea syndrome apply nasal continuous positive airway pressure for only part of the night or not every night.

Adult↗
PubMed1997

Determinants of effective ventilation during nasal intermittent positive pressure ventilation.

Our aim was to verify in healthy subjects submitted to nasal intermittent positive pressure ventilation (nIPPV) with a volumetric ventilator on controlled mode, whether changes in ventilator settings (delivered tidal volume (VT), respiratory frequency (fR) and inspiratory flow (V'I) could influence effective minute ventilation (V'E), thus allowing identification of the settings resulting in the highest V'E during nIPPV. We then compared these experimentally obtained "best" settings to those obtained retrospectively in a group of patients submitted to long-term nIPPV for clinical reasons. We studied 10 healthy subjects awake and asleep, and 33 patients with restrictive ventilatory disorders. Changes in delivered V'I (for a constant delivered VT and fR) led to significant changes in V'E. V'E was significantly higher when a given delivered V'E was obtained using higher fR and lower VT than when it was obtained using lower delivered fR and higher VT. Increases in fR generally resulted in increases in V'E. The "best" settings derived from these results were: VT: 13 mL.kg-1 of body weight; fR: 20 breaths.min-1 and V'I: 0.56-0.85 L.s-1. The corresponding average values found in the patient group were: delivered VT: 14 mL.kg-1; fR: 23 breaths.min-1 and delivered V'I: 0.51 L.s-1. Changes in minute ventilation resulting from modifications in ventilator settings can be attributed to the glottic response to mechanical influences. This leads to "ideal" settings quite different from the standard ones in intubated patients. Values derived from nasal intermittent positive pressure ventilation in healthy subjects seem to apply to patients submitted to long-term nasal intermittent positive pressure ventilation.

Adolescent↗
PubMed1996

Why should we enlarge the pharynx in obstructive sleep apnea?

Patency of the collapsible segment of the pharynx is dependent upon the interplay of anatomic and physiologic factors. The upper airway of the typical patient with obstructive sleep apnea (OSA) is structurally narrowed by fat deposits in the lateral pharyngeal walls. During wakefulness, the upper airway dilator muscles compensate for the structurally reduced pharyngeal size by increasing their activity, thereby pulling the tongue and soft palate forward. As a consequence, the cross-sectional area is relatively preserved, but the shape of the pharynx becomes elliptical along the anteroposterior axis. In the awake patient with OSA, patency of the pharynx is largely dependent upon increased dilator muscle activity. During sleep, the activity of the muscular apparatus of the pharynx decreases causing a critical narrowing. Because anatomic narrowing appears to be a basic feature, enlarging the pharynx should be beneficial, particularly if its lateral diameter can be increased. Whereas facial advancement surgery structurally increases the anteroposterior diameter of the pharynx, thereby accounting for the good results reported with this technique, it is doubtful that uvulopalatopharyngoplasty has a similar effect on either the anter-oposterior or lateral diameters of the pharynx.

Humans↗
PubMed1996

Respiratory failure due to tracheobronchomalacia.

A case is described of tracheobronchomegaly progressing to extensive tracheomalacia, complicated by episodic choking, recurrent pulmonary infections, and irreversible hypercapnic respiratory failure. A Y-shaped tracheobronchial stent was placed endoscopically to splint the trachea open, with excellent clinical and physiological improvement. New stent designs may provide long term palliation in selected cases of diffuse tracheal collapse or stenosis, and offer an alternative to surgical repair.

Airway Obstruction↗
PubMed1996

Nasal two-level positive-pressure ventilation in normal subjects. Effects of the glottis and ventilation.

The purpose of this study was to examine the behavior of the glottis during intermittent positive-pressure ventilation (nIPPV) using a two-level positive-pressure ventilator and to compare the glottic adaptation to this ventilatory mode with the one observed using volumetric ventilators, recently reported by us. Six healthy subjects were studied during both wakefulness and sleep. Their glottis was continuously monitored through a fiberoptic bronchoscope. We measured breath by breath the widest inspiratory angle formed by the vocal cords at the anterior commissure, the corresponding tidal volume, and other indices. We used the controlled ventilatory mode. The expiratory pressure was kept at 4 cm H2O, and the inspiratory pressure was increased by steps from 10 to 15 to 20 cm H2O. Increases in inspiratory pressure did not always lead to increases in effective ventilation reaching the lungs. This was due to a significant narrowing of the glottis by adduction of the vocal cords in all subjects. Periodic breathing with or without apneas were common during wakefulness, but especially during sleep, representing 10.5 +/- 11% (SD) of total sleep time. We conclude that effective ventilation during nIPPV using a two-level positive-pressure ventilator in the controlled mode is less predictable and less stable than during nIPPV using volumetric ventilators.

Adaptation, Physiological↗
PubMed1996

Movement arousals and sleep-related disordered breathing in adults.

Sleep fragmentation (an increase in the number of short EEG arousals) is considered a major determinant of excessive daytime sleepiness but is seldom quantified in sleep studies, and reference values are scarce at best. We present data on the movement arousal index (MAI) in five groups of subjects: normals, simple snorers, patients with the sleep apnea-hypopnea syndrome (SAHS), and patients with sleep-related oxygen desaturations due to chronic obstructive pulmonary disease or neuromusculoskeletal disorders. In normal subjects, the MAI was 13 +/- 7 (mean +/- SD). MAI was distinctly increased in most patients with SAHS and was strongly correlated with the apnea-hypopnea index and loss of both slow wave and REM sleep. It was corrected to normal by nasal continuous positive airway pressure (CPAP). There was some overlap of MAI between SAHS patients and snorers, suggesting that a minority of nonapneic snorers may suffer from daytime sleepiness due to upper airway dysfunction. Sleep fragmentation is not a feature of sleep-related hypoventilation due to COPD or neuromusculoskeletal disorders, and an increase of the number of movement arousals (MA) is very suggestive of upper airway dysfunction and of potential success of CPAP. Quantification of sleep fragmentation is feasible and clinically useful; it should be included in the assessment of sleep-related breathing disorders.

Adult↗