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Publications (65)
The goal of this study was to characterize sleep and respiratory parameters in children with sleep-disordered breathing (SDB) as compared to children without SDB. Data are from 198 children and adolescents referred for sleep center evaluation, 128 of whom were diagnosed with SDB. In children with SDB, obesity (> 95% wgt for age) was more common tha...
To determine sleep effects on baro- and ventilatory responses to transient chemo- and barostimulation in African-Americans and Caucasians, 26 nonobese normotensive young subjects (13 African-Americans and 13 Caucasians) were studied awake and in non-rapid-eye movement (NREM) and rapid-eye-movement sleep during induced transient hypoxemia (N2), hype...
Although sleep-related obstructive apnea is most often associated with transient arousal, the impact of this arousal on respiratory control remains unclear. We tested the hypotheses that acoustic arousing stimulation can generate a significant respiratory response during sleep in healthy subjects and that the magnitude or timing of this response is...
Although sleep-related obstructive apnea is most often associated with transient arousal, the impact of this arousal on respiratory control remains unclear. We employed binaural tone bursts (.5 second duration) to elicit repetitive transient arousals from sleep during polygraphic recordings in 5 adult volunteers. By this method, we elicited repetit...
Purpose: To assess the efficacy of adenotonsillar surgery in children with OSA. Methods: 23 children diagnosed with OSA by polysomnography (PSG) were re-studied with PSG following upper airway surgery: tonsillectomy & adenoidectomy=18, adenoidectomy only=4, tonsillectomy only=1. Age range=7 mos to 16 yrs (x=6.2yrs), with 5 pts <3yrs, 10 pts 3-6 yrs...
While peripheral chemoreceptor stimulation augments, and baroreceptor stimulation attenuates, sympathetic activity in awake humans, normative effects of transient peripheral chemostimulation on cardiac baroreceptor response (BR) have not been well defined. We have therefore studied 6 supine normal, non-obese young men: 3 African American (AA), 3 Ca...
Eight subjects (5 men, 3 women, ages 27 to 55) with obstructive sleep apnea syndrome (OSAS) were studied to quantify and compare electromyographic (EMG) activity of levator veli palatini (LVP) and palatoglossus (PG), two velopharyngeal muscles, and genioglossus (GG) during obstructive apnea cycles in non-rapid eye movement (NREM) sleep. EMG activit...
Six untreated male patients (age 19-55 yr) with obstructive sleep apnea underwent nocturnal polysomnography with acoustic stimulation to determine the effect of transient arousal on obstructive apneas during sleep. Binaural tone bursts (25-95 dB) were delivered in late expiration during the second obstructive apnea of a cycle consisting of four con...
Six healthy subjects (3 males, 3 females) were studied to assess phasic inspiratory responses of upper airway (UA) and diaphragm muscles to electrocortical arousal independent of other potential respiratory stimulation. Transient electroencephalographic (EEG) arousal (abrupt EEG frequency shift > or = 3 s without awakening) was induced during supin...
To assess the effects of long-term nasal continuous positive airway pressure (CPAP) in occlusive sleep apnea syndrome (OSA), 17 patients with severe symptomatic OSA had repeated spirometry, arterial blood gases, and nocturnal polysomnograms off nasal CPAP after 3 to 46 months of treatment with nasal CPAP. Without loss of weight or change in respira...
Arterial blood gas analysis was performed before and after 60 to 90 s of voluntary hyperventilation in 27 consecutive patients with occlusive sleep apnea syndrome (OSA) and daytime hypercapnia. The percentage of fall in PaCO2 from baseline was examined in relationship to age, body mass index, sleep-disordered breathing indices, and pulmonary functi...
Although a thoracic volume dependence of upper airway resistance and caliber is known to exist in seated subjects, the mechanisms mediating this phenomenon are unknown. To test the hypothesis that actively altered end-expiratory lung volume (EELV) affects upper airway resistance in the supine position and to explore the mechanisms of any EELV-induc...
A patient with Hunter syndrome and diffuse airway obstruction had daytime hypersomnolence, snoring, and alveolar hypoventilation. Polysomnography showed severe obstructive sleep apnea. In the past, all reported cases of sleep apnea in patients with mucopolysaccharidoses had been treated with tonsillectomy/adenoidectomy or tracheostomy. This patient...
We examined interactions between inspiratory duration (TI), expiratory duration (TE), and inspiratory (esophageal) pressure (Pes) generation in seven subjects with confirmed occlusive sleep apnea. Breath-by-breath values of TI, TE, and Pes were identified by digital computer during 21 260-s epochs of repetitive occlusive apnea during non-rapid-eye-...
To determine upper airway and respiratory muscle responses to nasal continuous negative airway pressure (CNAP), we quantitated the changes in diaphragmatic and genioglossal electromyographic activity, inspiratory duration, tidal volume, minute ventilation, and end-expiratory lung volume (EEL) during CNAP in six normal subjects during wakefulness an...
To determine the effects of internal respiratory loading and unloading on respiratory neuromuscular function, ventilatory (Vi), occlusion pressure (P0.15), transdiaphragmatic pressure (Pdi) and diaphragmatic electromyogram (EMGdi) responses to CO2 rebreathing were assessed in 6 normal volunteers rebreathing gas mixtures denser (63% SF6, 30% O2, 7%...
Among 118 patients with occlusive sleep apnea syndrome (OSA), defined as daytime hypersomnolence and an apnea hypopnea index (AHI) greater than ten events/h, 41 women were compared with 77 men. Body mass index, spirometric study, PaO2, PaCO2, and results from nocturnal polysomnography were examined in a two-way analysis of variance (ANOVA) for the...
To assess the relative contributions of age, gender, obesity, pulmonary function, and the severity of sleep-induced respiratory abnormalities to the development of alveolar hypoventilation in patients with occlusive sleep apnea syndrome, prospective data from III patients with occlusive sleep apnea were analyzed by stepwise logistic and multiple re...
Eight patients with occlusive sleep apnea were monitored during non-rapid-eye-movement (NREM) sleep to study the factors that contribute to negative inspiratory pressure generation and thus upper airway occlusion. End-expiratory lung volume assessed by respiratory inductive plethysmography [sum of end-expiratory levels (SUM EEL)] increased early an...
To study the effects of continuous positive airway pressure (CPAP) on lung volume, and upper airway and respiratory muscle activity, we quantitated the CPAP-induced changes in diaphragmatic and genioglossal electromyograms, esophageal and transdiaphragmatic pressures (Pes and Pdi), and functional residual capacity (FRC) in six normal awake subjects...
To study respiratory muscle interaction in patients with occlusive apnea, diaphragmatic electromyogram (EMGdi) and gastric, pleural, and transdiaphragmatic pressures (Pga, Ppl, and Pdi, respectively) were studied in seven patients during non-rapid-eye-movement (NREM) sleep. Diaphragmatic force output, as assessed by Pdi, followed the periodic chang...
To test the hypothesis that occlusive apneas result from sleep-induced periodic breathing in association with some degree of upper airway compromise, periodic breathing was induced during non-rapid-eye-movement (NREM) sleep by administering hypoxic gas mixtures with and without applied external inspiratory resistance (9 cmH2O X l-1 X s) in five nor...
To study respiratory timing mechanisms in patients with occlusive apnea, inspiratory and expiratory times (TI and TE) were calculated from the diaphragmatic electromyogram obtained in seven patients during non-rapid-eye-movement (NREM) sleep. Peak diaphragmatic activity (EMGdi) had a curvilinear relationship with TI during the ventilatory and occlu...
Sleep-induced periodic breathing has been suggested to lead to the development of occlusive apneas in patients with sleep apnea syndrome. If this were true, patients with Cheyne-Stokes respiration should also develop upper airway occlusion during sleep. To study this hypothesis, 6 nonobese patients with Cheyne-Stokes respiration lacking evidence fo...
To assess respiratory neuromuscular function and load compensating ability in patients with chronic airway obstruction (CAO), we studied eight stable patients with irreversible airway obstruction during hyperoxic CO2 rebreathing with and without a 17 cmH2O X l-1 X s flow-resistive inspiratory load (IRL). Minute ventilation (VE), transdiaphragmatic...
To study the dynamics of respiratory drive and pressure in patients with occlusive apneas, diaphragmatic electromyogram (EMGdi), esophageal pressure (Pes), and genioglossal electromyogram (EMGge) were monitored during nocturnal sleep in five patients. Both EMGs were analyzed as peak moving time average, and Pes was quantitated as the peak inspirato...
The relationships between pulmonary function and sleep-induced respiratory events were studied in 34 consecutive male patients with suspected sleep apnea syndrome. In view of the effects of obstructive airway disease on pulmonary volume and airway resistance (Raw), patients were divided into two groups, those with and those without obstructive airw...
Magnetometers measure changes in antero-posterior diameters of the rib cage and abdomen while respiratory inductance plethysmography (RIP) measures changes in chest wall cross-sectional area. We compared Konno-Mead diagrams derived from isovolume calibrated magnetometers and RIP in the DC-mode during room air and CO2 rebreathing in the sitting and...
This paper analyzes the craniofacial morphology in a patient with typical Hallermann-Streiff syndrome (HSS) who developed symptomatic cardiorespiratory deficiency at the age of 48 years. The patient had obstructive sleep apnea (OSA), hypoxia, hypercarbia, pulmonary hypertension, tricuspid insufficiency, and right ventricular failure. Analysis of ce...
The effects of changing from the sitting to supine position on respiratory muscle function was assessed during CO2 rebreathing. Gastric (Pg), pleural (Ppl) and transdiaphragmatic (Pdi) pressures and thoracoabdominal motion were monitored. Diaphragmatic EMG was measured by a bipolar esophageal electrode and quantitated as a moving time average (EMGd...
In order to explore the efficacy of expiratory positive airway pressure (EPAP) in the prevention of sleep-induced respiratory abnormalities, we studied 9 patients with typical presentation of hypersomnia-sleep apnea syndrome 1 wk apart, without and with 10 cm water of EPAP. We found that EPAP significantly reduced apnea index (p less than 0.01), ma...
We investigated the respiratory muscle contribution to inspiratory load compensation by measuring diaphragmatic and intercostal electromyograms (EMGdi and EMGic), transdiaphragmatic pressure (Pdi), and thoracoabdominal motion during CO2 rebreathing with and without 15 cmH2O X l-1 X s inspiratory flow resistance (IRL) in normal sitting volunteers. D...
In order to study the relationship between sleep-induced periodic breathing and the development of occlusive sleep apneas, 6 patients with hypersomnia-sleep apnea syndrome were studied during nocturnal sleep before and approximately 1 month after therapeutic tracheostomy. Post-tracheostomy studies were performed in open and closed tracheostomy stat...
To define the roles of mechanical loading, respiratory neuromuscular control, and sleep apnea in the pathogenesis of obesity hypoventilation, respiratory muscle drive and output, assessed by diaphragmatic electromyogram (EMGdi) and mouth occlusion pressure (P 0.15), respectively, were determined during CO2 chemostimulation in nonobese volunteers wh...
To define the pathogenesis of apneas, eight patients with hypersomnia-sleep apnea syndrome were studied during nocturnal sleep. Diaphragmatic and genioglossal electromyograms quantitated as moving time average activity showed parallel periodic fluctuations resembling the pattern of Cheyne-Stokes breathing. Hypopneas and occlusive apneas occurred at...
A single gastroesophageal catheter was used for simultaneous measurements of diaphragmatic electromyogram (EMGdi), esophageal, and gastric pressures in 10 normal volunteers. The catheter consisted of 2 polyethylene tubes, each with an outer diameter of 1.70 mm and an inner diameter of 1.19 mm, 2 platinum wire coils, and esophageal and gastric latex...
In order to define the relationship between central control of upper airway and respiratory muscle function, diaphragmatic electromyogram (EMGdi) and genioglossal EMG (EMGge) responses to isocapnic hypoxia were studied in 6 awake supine volunteers. Both EMGs were processed and quantitated as moving time average activity. In all subjects, EMGge show...
To assess the relationship between central control of upper airway and respiratory muscle, simultaneously recorded diaphragmatic electromyogram (EMGdi) and genioglossal EMG (EMG ge) responses to CO2 rebreathing were compared in five supine volunteers. Both EMGs were quantitated in terms of inspiratory peak moving time-average activity. In all subje...
Diaphragmatic EMG (EMGdi) analyzed as a moving time average and quantitated as peak inspiratory activity
( [`(X)]p )\left( {\bar X_p } \right)
was used with tidal volume (V
T)to assess the changes in inspiratory “of-switch” threshold in six normal subjects during three CO2 rebreathing experiments performed on different days. The qualitative charact...
The effects of external elastic loading (EL) (19 cmH2O/l), applied continuously (C) and intermittently (I) during CO2 rebreathing, on diaphragmatic electromyogram (EMGdi), mouth occlusion pressure (P0.15), and ventilation (VI) were studied in normal subjects. EMGdi was analyzed as moving time average and quantitated in terms of peak (mean p) and av...
We report a case of respiratory failure caused by Strongyloides stercoralis in a patient with a renal transplant; the respiratory failure showed dramatic response to therapy with thiabendazole. The clinical aspects of infestation with S stercoralis in the immunocompromised host are discussed, and features are demonstrated which may have significant...
The effects of inspiratory flow resistance on mouth occlusion pressure (P0.15) and diaphragmatic EMG (EMGdi) responses to CO2 rebreathing were studied in normal subjects. Occlusion pressures were measured 150 msec after onset of an inspiratory effect; EMGdi was analyzed as a moving time average and quantified in terms of peak activity and rate of r...
This report on methods of evaluating respiratory control will focus first on a basically clinical approach using methods easily available or amenable to clinical practice, and second on a more sophisticated organized approach to studying the control system which currently is only partially available for practical clinical testing.
The effects of electrode position and gastric-balloon anchoring on esophageal diaphragmatic EMG (EMGdi) responses to CO2 rebreathing were studied in seven normal sitting humans using an esophageal catheter that consisted of four platinum wire coils enabling simultaneous recording of three EMGdi signals from three different sites in the esophagus. A...
Extremely obese patients may develop a disorder of the respiratory control system manifested by CO 2 retention. Despite numerous clinical and physiologic studies of patients with obesity and hypoventilation, the mechanisms causing this syndrome are not well understood. The authors have investigated the control of ventilation in exceedingly obese pa...
The EMGdi response to both isocapnic hypoxia and hyperoxic hypercapnia was studied in the same sitting in six normal subjects. Rebreathing methods achieving "open loop" conditions were used. EMGdi was quantified as a moving time average. In almost all subjects, during hypoxia changes in EMGdi were inversely and hyperbolically related to changes in...
Central neural drive to the respiratory muscles can be assessed by a variety of methods. These include measurement of respiratory nerve and muscle electrical activity, measurement of the pressures generated by the contraction of respiratory muscles, and measurement of the final output of the respiratory system––ventilation. We have assessed these o...
We determined the relationship between mouth occlusion pressure and diaphragmatic electromyography during CO2 rebreathing with and without inspiratory flow resistance. Diaphragmatic electromyography was measured as a moving time average; occlusion pressures were measured 150 msec after onset of an inspiratory effort against a closed airway (P.15)....
Five cases of nodular pulmonary sarcoidosis are presented. That nodular infiltration represents a reversible stage of sarcoidosis is suggested by the fact that all patients demonstrated roentgenographic resolution of these infiltrates. In four of the five subjects, tests of pulmonary function showed restrictive disease which remained unchanged or w...
To determine a reliable quantitative method of measuring diaphragmatic EMG (EMGdi), electrical activity of the diaphragm was obtained via an esophageal electrode during CO2 rebreathing in 6 normal males and processed three different ways: 1) integration (area), 2) as a moving time average, and 3) as a moving time variance. Integrated activity was q...
To evaluate mouth occlusion pressure as an index of neural drive to the respiratory muscles that is independent of lung mechanics, the occlusion pressure response to rebreathing was studied in 7 normal subjects under control conditions and during flow-resistive loading. Inspiratory, expiratory, and combined inspiratory-expiratory flow resistances o...
Changes in phrenic nerve activity, quantified as a moving time average, PNG(t), were characterized during complete airway occlusion at functional residual capacity (FRC) and compared to simultaneously occurring changes in intratracheal pressure. In anesthetized cats breathing room air and during CO2 breathing, PNG(t) during occlusion was the same a...
In 7 normal subjects, mouth occlusion pressure was evaluated as an index of neural drive to the respiratory muscles during CO2 rebreathing, with and without the addition of 2 degrees of elastic loads. During control and loaded rebreathing, changes in both mouth occlusion pressure and ventilation were linearly related to changes in end-tidal PCO2. W...
In conclusion, it is suggested that:
(1)Electrical activity of nerve and muscle can be used to study the pattern of neural drive to respiratory muscles.
(2)Methods of analysis should include those that resolve changes in the pattern of neural discharge with respect to time; namely, moving average and moving variance. Both peak and slope parameters...
The measure of diaphragm electrical activity in man to study regulation of ventilation has in the past been hampered by significant technical problems. This paper presents the results of some recent investigations on diaphragmatic EMG (EMG(di)) in normal human subjects, utilizing new methods of EMG processing and quantification, which have not been...
A 73-year-old man with malignant lymphoma who was undergoing treatment with systemic chemotherapy presented with an acute, febrile illness associated with cough and sputum production. The patient developed bilateral, diffuse, pulmonary interstitial infiltrates with rapidly progressive respiratory insufficiency. The diagnosis was made by demonstrati...
The biochemical composition of bronchial secretions was studied in patients with chronic obstructive pulmonary disease (COPD) and in normal subjects. The glycoprotein constituents of bronchial mucus were assessed by determining the contents of N acetyl neuraminic acid and fucose and the ratio of one to the other. Secondary bonding of the sputum gel...
