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Biomedical subjects

D O Rodenstein

Publications and source records attributed to D O Rodenstein.

86 records · Page 5Linked to original sources
PubMed1985

Infants are not obligatory nasal breathers.

It is widely believed that infants are obligatory nasal breathers. We studied 19 infants, 1 to 230 days of age, for respiratory response to acute nasal occlusion. Lips were kept apart. Oropharyngeal structures were monitored by fluoroscopy, whereas respiratory movements and oral flow were recorded. We systematically observed before and during nasal occlusion tight apposition of the soft palate and the tongue, closing the oropharyngeal isthmus. After a variable time (mean 7.8 s, range 0.6 to 32 s), the soft palate rose and oral breathing was initiated. Time required to mouth-breathe was related to age and/or conscious state, older and/or awake infants responding faster than younger and/or asleep infants. In 9 others, when nasal occlusion was performed with the mouth closed, results were comparable to those obtained in infants with mouths open. In 3 infants, electroencephalograph (EEG) records showed quiet non-REM sleep. Nasal occlusion resulted in an immediate arousal reaction, followed after a variable time by mouth breathing. We conclude that infants are not obligatory nasal breathers. They can breathe through the mouth by detaching the soft palate from the tongue, thus opening the oropharyngeal isthmus.

Female↗
PubMed1985

Pattern of inhalation of tobacco smoke in pipe, cigarette, and never smokers.

There is controversy on whether both primary and secondary pipe smokers do inhale tobacco smoke. We studied inhalation of tobacco smoke in 6 primary and 6 secondary pipe smokers and compared it with that in 20 cigarette smokers and 11 never smokers. Respiratory movements were assessed with inductive plethysmography, nasal flow through measurements of nasal pressure, oral flow with an oral thermistor, puffing through pressure measurements in the cigarette holder or the pipe, and upper airways by fluoroscopy. In all pipe smokers except 1, breathing and smoking appeared as independent activities. The former was exclusively nasal, whereas the latter was exclusively oral. Smoke was sucked and puffed by a to-and-fro movement of the tongue sliding along the soft palate. The oropharyngeal isthmus was closed (or only intermittently opened) by the apposition of the soft palate and the tongue, thus preventing overt inhalation of smoke. In most cigarette smokers, smoking interfered with the breathing route. Once smoke was sucked into the mouth, the oropharyngeal isthmus opened and inspiration proceeded through both mouth (with inhalation of smoke) and nose. Cigarette smoking interfered also with the evenness of ventilation. Never smokers avoided inhalation by oropharyngeal closure followed by oral expiration. We conclude that the oropharyngeal isthmus is the essential gate controlling smoke inhalation. Most secondary pipe smokers are able to change their smoking pattern and avoid overt inhalation when switching from cigarette to pipe smoking. The inhalation pattern appears to be acquired in the course of the smoking history.

Adult↗
PubMed1984

Soft palate and oronasal breathing in humans.

In 20 naive patients without respiratory impairment, we investigated the ability of the soft palate to direct airflow during breathing. Patients were connected to a spirometer, without noseclip. No instructions were given on the breathing route. During quiet respiration, 15 patients breathed solely through the nose, despite an open mouth. During forced vital capacity (FVC) maneuvers, 19 patients expired exclusively through the mouth. When specifically asked to breathe quietly through the mouth, pure nasal breathing was no longer observed. Tidal volume (VT) or FVC were comparable when patients were asked to breathe through the mouth, with or without noseclip: 0.67 +/- 0.46 vs. 0.60 +/- 0.21 liter for VT (mean +/- SD); 4.05 +/- 0.65 vs. 4.18 +/- 0.70 liters for FVC. In eight separate healthy volunteers, the soft palate was shown by fluoroscopy to close the oropharyngeal isthmus during quiet breathing (resulting in pure nasal breathing) and to close the nasopharynx during FVC efforts (resulting in mouth breathing). During oronasal breathing, the soft palate lay in between the tongue and the posterior pharyngeal wall. These data suggest that when both mouth and nose are open, the soft palate is responsible for the partitioning of oronasal flow.

Fluoroscopy↗
PubMed1983

Extrathoracic airways changes during plethysmographic measurements of lung volume.

In six healthy subjects cineradiographic studies during panting against a closed shutter showed widening and narrowing of the whole extrathoracic airways. At the epiglottic level, the mean lateral maximum diameter was 121% of the minimum diameter for an applied pressure of 11.4 cm H2O and 152% for 28.4 cm H2O, while posteroanterior diameter changes were 148% for 12.3 cm H2O and 182% for 28.2 cm H2O, respectively. There was a significant correlation between anteroposterior diameter changes and mouth pressure (Pm) swings (P less than 0.05). In 6 cadavers, the compliance of extrathoracic airways (isolated from the lower respiratory tract by an inflated balloon in the upper trachea) was 1.5 ml X cm H2O-1 after adding 30 ml of air, and 1 ml X cm H2O-1 after removing 30 ml of air. Flow rate in and out the extrathoracic airways averaged 0.089 and 0.163 L X sec-1 for swings in Pm of 9.5 and 18.5 cm H2O, respectively. There was a significant correlation (P less than 0.05) between flow rate and delta Pm. For a given delta Pm, flow was higher in those cadavers with more compliant extrathoracic airways. We conclude that extrathoracic airways change their volume during panting, and that these volume changes, as well as the internal flow rate thus created, depend on the Pm swings.

Adult↗
PubMed1983

Frequency dependence of plethysmographic volume in healthy and asthmatic subjects.

In airway obstruction, thoracic gas volume derived from mouth pressure vs. plethysmographic volume changes (TGVm) is overestimated, whereas TGVes, derived from esophageal pressure vs. plethysmographic volume changes, is not (J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 52: 939-954, 1982). The reason appears to be that mouth pressure swings are less than alveolar pressure swings. We measured TGVm and TGVes in six normal subjects and in nine asthmatic patients before and during bronchospasm, while panting at the same lung volume at 0.8 Hz (low), 2-2.5 Hz (medium), and 4.5-5 Hz (high). No difference was observed between TGVm and TGVes (P greater than 0.05) at any frequency (f) in normal subjects or asthmatics before bronchospasm. During bronchospasm, TGVm and TGVes were similar at low f. However, TGVm increased from 5.66 +/- 1.16 (SD) liters at low f to 6.50 +/- 1.71 liters at medium f (P less than 0.01), resulting in a TGVm 1.16 +/- 0.95 liters higher than TGVes (P less than 0.01). In three asthmatics during bronchospasm, mean TGVm-TGVes difference was 0.01 liter at low f, 0.26 liter at medium f, and 0.73 liter at high f. Surprisingly TGVes was in average 5% higher at low f than at medium or high f, both in normal subjects and asthmatics. A similar pattern was observed for TGVm, except in asthmatics during bronchospasm. We conclude that in airway obstruction overestimation of TGVm is frequency dependent and can be avoided by panting at low f. However, at this f TGV is 5% larger than at higher f, difference which is not related to airway obstruction.

Acetylcholine↗
PubMed1983

Airway closure in humans does not result in overestimation of plethysmographic lung volume.

Exercise Physiol. 52: 638-641, 1982) have shown in dogs that airway closure may induce rib cage deformation and nonhomogeneous alveolar pressure swings, and they have suggested that this could lead to thoracic gas volume (TGV) overestimation by body plethysmography. However, in humans the rib cage is less easy to distort than in dogs. In four healthy volunteers we measured TGV by plethysmography before (B) and during (D) the occlusion of the middle and lower right lobes by a balloon (attached to a double-lumen catheter) positioned in the intermediate right bronchus. Subjects were trained to perform panting maneuvers preferentially with intercostals and accessory muscles or the diaphragm. Five to eleven TGV measurements were made in each subject with each panting pattern B and D occlusion. Balloon inflation resulted in no change in TGV whether low [13.3 +/- 3.4 (SD) cmH2O] or high (46.8 +/- 8.4 cmH2O) transdiaphragmatic pressures (Pdi) were used: TGV 4.0 +/- 0.4 (B) vs. 4.0 +/- 0.4 liters (D) and 4.3 +/- 0.4 (B) vs. 4.3 +/- 0.4 liters (D) for low and high Pdi, respectively. Thus, in trained subjects performing maneuvers aimed to distort the rib cage, no pressure difference was observed between the occluded and the nonoccluded lung during panting against the closed shutter. We conclude that it is unlikely that the mechanism proposed by Brown et al. might explain errors in lung volume measurements by body plethysmography in humans.

Adult↗
PubMed1983

Emotional laryngeal wheezing: a new syndrome.

A 41-yr-old psychologically disturbed woman presented with attacks of paroxystic dyspnea, laborious expiration, cough, and expiratory wheezing. She had been treated for bronchial asthma and had developed an iatrogenic Cushing's syndrome. Wheezing had maximal intensity over the larynx, and fiberoptic bronchoscopy showed an almost closed glottis orifice during its production. Lung function tests were normal both before and during the attacks. Inhalation challenge tests with acetylcholine and histamine were negative. During the attacks the patient breathed near residual volume, and tidal flows reached the maximal flow-volume envelope. We suggest that wheezing was produced by high flows passing through a narrow glottis orifice. The association of expiratory wheezing of laryngeal origin with normal overall lung function should be kept in mind, because it can be easily confounded with bronchial asthma, and result in therapeutic errors.

Adult↗
PubMed1983

Absence of nasal air flow during pursed lips breathing. The soft palate mechanisms.

During pursed-lips (PL) breathing, even though expiratory air-flow resistance is probably higher than during nasal breathing, there is no air flow through the nose. This should imply an active mechanism that prevents air from escaping through the nares. In 6 patients with chronic obstructive lung disease (FEV1/FVC 34.5 +/- 11.8%; mean +/- 1 SD), nasal resistance averaged 2.6 +/- 0.5 cm H2O.L-1.s-1, whereas translabial resistance (during PL expiration) was 5.7 +/- 0.7 cm H2O.L-1.s-1 (p less than 0.005 by paired t test). Nasal air flow during PL expiration was zero. In all patients, cineradiographic studies showed during the expiratory phase of PL breathing that the soft palate rose to closely contact the posterior pharyngeal wall, completely occluding the entrance to the nasopharynx. This upward movement of the soft palate was of active nature. The palate muscles should be considered as accessory respiratory muscles.

Aged↗
PubMed1982

Demonstration of failure of body plethysmography in airway obstruction.

To demonstrate the role of extrathoracic airways in the overestimation of lung volumes by body plethysmography in airway obstruction, we induced in six normal subjects an artificial airway stenosis by inflating a balloon in the lower trachea. We measured thoracic gas volume in a body plethysmograph simultaneously from mouth pressure (Pm) vs. plethysmographic volume (Vbox) (TGVm) and from esophageal pressure (Pes) vs. Vbox (TGVes). During control measurements there was no difference between TGVm and TGVes (P greater than 0.1) in any subject. Balloon inflation (B) resulted in a significant (P less than 0.01) decrease of specific airway conductance (sGaw) from a mean value of 0.199 +/- 0.66 (SD) to 0.025 +/- 0.01 cmH2O-1 . s-1. TGVm significantly (P less than 0.02) exceeded TGVes in every subject (mean diff 1.24 +/- 0.56 liters) and Pm lagged behind Pes. In two subjects studied at different levels of airway obstruction we found a significant (P less than 0.05) correlation between TGVm-TGVes difference and sGaw. Bypassing the extrathoracic airways by a cuffed endotracheal tube resulted in each case in a degree of airway obstruction comparable to that during balloon inflation (sGaw 0.019 +/- 0.004 cmH2O-1 . s-1), but no difference between TGVm and TGVes (P greater than 0.1). We conclude that lung volume is overestimated by plethysmography in airway obstruction. The overestimation is due to the presence of a compliant extrathoracic airway, and it probably depends on both the degree of airway obstruction and the value of compliance of the extrathoracic airway.

Adult↗
PubMed1982

Reassessment of lung volume measurement by helium dilution and by body plethysmography in chronic air-flow obstruction.

We have previously shown that in some asthmatic patients, plethysmographic total lung capacity, measured from mouth pressure versus plethysmographic volume (Vbox) changes (TLCm), is overestimated, whereas TLCes, derived from esophageal pressure versus Vbox changes, is an accurate estimate of lung volume (VL). We studied 24 patients with chronic airflow obstruction (mean forced expiratory volume in one second, 1.23 L(SD:0.64 L) and mean specific airway conductance, SGaw, 0.052 +/- 0.016 cm H2O-1 X S-1) to reassess the relative merits of TLCm and the 7-min closed-circuit He dilution technique (TLCHe) in this condition. The TLCHe (6.54 +/- 1.09 L) was significantly less (p less than 0.001) than both TLCm (7.53 +/- 1.20 L) and TLCes (7.16 +/- 1.12 L), whereas TLCm was greater than TLCes (p less than 0.001). Differences between TLCes and TLCHe (ranging from -0.11 to 2.17 L) and between TLCm and TLCes (from -0.10 to 1.48 L) were correlated to the degree of airway obstruction as assessed by SGaw (p less than 0.001 and p less than 0.01, respectively). We conclude that VL is overestimated by TLCm and underestimated by TLCHe in moderate to severe chronic air-flow obstruction. The "trapped gas" volume (TLCm to TLCHe difference) is actually made up by these two additive errors.

Adult↗
PubMedDate not supplied

Nasal occlusion during sleep in normal and near-miss for sudden death syndrome infants.

Obligatory nasal breathing has been suggested in the past as a contributor to sudden infant death syndrome (SIDS): nasal obstruction would result in death as infants were unable to breathe orally. To test this hypothesis, we studied 55 normal and 14 near-miss for SIDS infants during a whole-night polysomnography. On several occasions, the infant nares were gently occluded by the fingertips of the investigator. Infants continued to make respiratory efforts against the occluded nose for a variable time (apnoea time), then opened the mouth and started to breathe through it. Mean apnoea time in normal infants was 4.76 +/- 3.41 s (means +/- SD), and 6.54 +/- 4.25 s in near-miss for SIDS ones. These figures were not significantly different. Analysis according to sleep stage (quiet sleep: 4.08 +/- 3.24 s in normals and 6.50 +/- 4.18 s in near-miss for SIDS ones; active sleep: 6.54 +/- 3.67 s in normals and 6.58 +/- 4.76 s in near-miss for SIDS ones) did not disclose any significant difference between groups. There was no significant relationship between apnoea time and age in either group. In many cases, an arousal preceded the resumption of (oral) flow. However, in almost half of the occlusions, oral breathing was initiated during continuing sleep. We conclude: 1) infants are not obligatory nasal breathers, and 2) the nasal obstruction hypothesis should be discarded in the etiology of SIDS.

Airway Resistance↗
PubMedDate not supplied

Reevaluation of the radiographic method for measurement of total lung capacity.

To clarify whether the radiographic estimate of total lung capacity (TLC) using the method of Barnhard et al., as modified by Loyd et al., yields accurate values, we measured TLC in 20 young healthy subjects with the above technique (Vb). We compared it to the more sophisticated radiologic method of Pierce et al. (Vp) and to plethysmographic measurements (Vbox). Plethysmographic results, 7.38 +/- 0.94 l (mean +/- SD) or 101.7% of predicted, were significantly higher than Vb (mean difference 0.53 +/- 0.68 l; p less than 0.005 by paired t test), but were not significantly different from Vp (mean difference 0.13 +/- 0.52 l). Based on these and previous data, we conclude that the Pierce et al. approach yields more accurate results than the Barnhard and Loyd method, although individual data, in both methods, should be interpreted cautiously.

Adult↗