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Biomedical subjects

R P Millman

Publications and source records attributed to R P Millman.

At least 19 recordsLinked to original sources
PubMed1992

Studies in the genetics of obstructive sleep apnea. Familial aggregation of symptoms associated with sleep-related breathing disturbances.

Previous studies of single families have suggested that familial factors may be important in the pathogenesis of obstructive sleep apnea. In this report, the role of inheritance in obstructive sleep apnea was assessed by quantitating the degree of familial clustering of symptoms associated with sleep-related breathing disorders. In total, 272 subjects from 29 families identified through an index case with obstructive sleep apnea and 21 control families with no relative known to have sleep apnea were studied with questionnaires that ascertained health status and symptoms. The unadjusted odds ratios of habitual or disruptive snoring, breathing pauses, and excessive day-time sleepiness in subjects with a single relative with the same symptom were 1.40 to 1.53 (p less than 0.05). Odds ratios increased progressively for subjects with increasing numbers of symptomatic relatives). Adjustment for body mass index, age, and gender modestly reduced these odds ratios to 1.33 to 1.42. These data suggest a significant familial aggregation of symptoms associated with sleep-disordered breathing that appears independent of familial similarities in weight.

Adult↗
PubMed1992

Sleep-disordered breathing in patients with Duchenne muscular dystrophy using negative pressure ventilators.

We studied the occurrence of nocturnal disordered breathing events and O2 desaturations in 12 patients with late-stage Duchenne muscular dystrophy (DMD) using negative pressure ventilators. We also assessed the effects of O2 supplementation and nasal continuous positive airway pressure (CPAP) on disordered breathing events in selected patients and examined sleep quality in a small subgroup. Average age was 23 + 2 years and FVC was 293 + 33 ml. Eleven of the 12 patients had more than five disordered breathing events per hour during nocturnal monitoring, and the lowest O2 saturation was < 85 percent in nine patients. Nasal O2 (2 L/min) during negative pressure ventilation in four patients did not alter the frequency of disordered breathing events, prolonged the mean and maximum durations of events, and failed to eliminate severe O2 desaturations in two patients. Nasal CPAP was used in two patients during negative pressure ventilation and completely eliminated disordered breathing events in both. Overnight polysomnography during negative pressure ventilation in three patients demonstrated frequent awakenings that fell in frequency following elective tracheostomy in two patients and use of nasal CPAP in one. We conclude that negative pressure ventilation in patients with late-stage DMD is associated with frequent disordered breathing events and severe O2 desaturations in many patients. Concomitant use of O2 supplementation may prolong the events, but a switch to positive pressure ventilation or addition of nasal CPAP is effective therapy.

Adolescent↗
PubMed1991

Nocturnal positive-pressure ventilation via nasal mask in patients with severe chronic obstructive pulmonary disease.

Intermittent positive pressure ventilation administered nocturnally via a nasal mask has been associated with improvements in pulmonary function and symptoms in patients with restrictive ventilatory disorders. We hypothesized that nocturnal nasal ventilation (NNV) would bring about similar improvements in patients with severe chronic obstructive pulmonary disease (COPD). The study used a randomized, crossover design, with subjects undergoing NNV or "standard care" for sequential 3-month periods. Of 23 patients with obstructive lung disease and a FEV1 less than 1 L who were initially enrolled, 4 were excluded because of obstructive sleep apnea prior to randomization. Among the remaining 19 patients, 7 withdrew because of intolerance of the nose mask, 5 were withdrawn because of intercurrent illnesses, and 7 completed both arms of the protocol. These latter 7 patients used the ventilator for an average of 6.7 h/night, and 3 of the 7 had partial relief of dyspnea during ventilator use. However, in comparison with studies performed upon initiation or after the standard care arm of the study, studies performed after 3 months of NNV revealed no improvements in pulmonary function, respiratory muscle strength, gas exchange, exercise endurance, sleep efficiency, quality or oxygenation, or dyspnea ratings. The only improvements observed were in neuropsychological function, possibly related to a placebo effect or another unknown mechanism. Despite the small sample size, our study indicates that NNV is not well tolerated by and brings about minimal improvements in stable outpatients with severe COPD.

Aged↗
PubMed1991

Measurement of sleep-related breathing disturbances in epidemiologic studies. Assessment of the validity and reproducibility of a portable monitoring device.

The feasibility and reliability of measuring sleep-related breathing disorders with a portable monitor (PM) were assessed in a heterogeneous population, consisting of 31 patients recruited from a sleep laboratory and pulmonary disease clinic, 16 participants in a genetic-epidemiologic study of sleep apnea, and four volunteers with no specific sleep complaints. The validity of measurements made by the PM was assessed with comparisons of respiratory parameters made with the PM to those determined with in-hospital polysomnography (PSG) (25 studies). Reproducibility was assessed in 29 subjects who underwent in-home monitoring on two occasions. There was a high level of agreement between the number of respiratory events (apneas or hypopneas) per hour of estimated sleep (respiratory disturbance index, RDI) recorded with the PM and PSG and log-transformed (r = 0.96). Using a RDI of greater than or equal to 10 to define "abnormality," 20 of the 21 subjects who would have been classified as abnormal with PSG were classified similarly with use of the PM. A similar high level of agreement was demonstrated for the log-transformed RDI determined with replicate in-home studies (r = 0.94). No evidence of a "first-night effect" for the RDI was suggested in studies performed with the PM; ie, RDI was 18.4 +/- 27.7 and 17.4 +/- 25.7 (mean +/- SD) for first and second night studies, respectively (p = 0.21). A second compared with an initial study with the PM would have resulted in reclassification of abnormality based on an RDI of greater than or equal to 10 in one subject. These findings suggest that measurement of the RDI with in-home monitoring provides a valid and highly reproducible index for assessment of sleep-related respiratory disturbances for use in epidemiologic studies of general populations.

Adult↗
PubMed1991

Sleepwalking precipitated by treatment of sleep apnea with nasal CPAP.

A 33-year-old man with a long history of snoring, observed apneic episodes, and excessive daytime sleepiness, underwent all-night polysomnography, which demonstrated severe obstructive sleep apnea. During the nasal CPAP trial, two episodes of sleepwalking were observed during a period of delta sleep rebound.

Adult↗
PubMed1991

Daytime hypertension in obstructive sleep apnea. Prevalence and contributing risk factors.

We examined the prevalence of daytime hypertension in a modern sample of patients with obstructive sleep apnea (OSA) and assessed the relative risk factors contributing to the development of hypertension in this disorder. Daytime hypertension was present in 92 (45 percent) of 206 male and female patients with OSA. Stepwise logistic regression revealed that only age and body mass index (BMI) were predictors of hypertension in this population. A subsample of 152 male patients with OSA was then compared to 904 men identified from a geographically and ethnically similar general population. When one controlled for age and BMI, the prevalence of hypertension in the two groups was the same except for those aged 25 to 44 years who were markedly obese (BMI greater than 31 kg/m2). In this group, 47 percent of the patients with OSA were hypertensive vs 26 percent of control subjects (p less than 0.05). Our data suggest that the high prevalence of hypertension in OSA is primarily related to age and the excess obesity seen in these patients. In morbidly obese young patients with OSA, factors directly related to OSA may also be contributing to the development of hypertension. With increasing age, other competitive risks may obscure any independent effect that OSA may exert.

Adult↗
PubMed1991

Causes and consequences of blood pressure alterations in obstructive sleep apnea.

The obstructive sleep apnea (OSA) syndrome has been considered to be a cause of both transient blood pressure elevations during sleep and sustained hypertension during the awake state. The purpose of this review was to examine critically the existing literature regarding (1) the blood pressure alterations associated with OSA, (2) causal mechanisms relating specific blood pressure alterations to OSA, and (3) potential consequences of the systemic circulatory abnormalities associated with OSA. Particular attention was directed at studies that assessed the prevalence of OSA in patients with hypertension and that examined the effects on blood pressure of treatment of OSA. We conclude that patients with OSA have abnormal sleep blood pressure patterns, manifested most frequently by apnea-associated blood pressure elevations. Confounding factors such as obesity and antihypertensive drug therapy, and conflicting evidence regarding changes in daytime blood pressure after therapy for OSA, make it premature to conclude that OSA and daytime hypertension are directly associated. Circumstantial evidence suggests that the blood pressure alterations that occur during sleep could contribute to the high cardiovascular morbidity in patients with OSA. Further research into the relationship between OSA and hypertension should improve the future care of patients with these conditions and enhance our understanding of cardiopulmonary pathophysiology.

Blood Pressure↗
PubMed1990

Changes in airway resistance following nasal provocation.

Controversy exists on whether stimulation of the nasal mucosa results in reflex bronchoconstriction. To address shortcomings in previous experimental design, we performed double-blind randomized nasal challenges in asthmatic patients with allergic rhinitis and in controls. Using pledgets containing 10-microliters aliquots of 0.9% saline or increasing concentrations of methacholine or histamine, we were able to increase nasal resistance significantly in both groups. Only methacholine caused an increase in lower airway resistance, and this could be blunted by premedication of the nasal mucosa with phenylephrine. This suggests that the effect on lower airway resistance was due to systemic absorption. Our study does not support the existence of a nasobronchial reflex from mechanical alteration of the nasal mucosa.

Adult↗
PubMed1990

A family study of sleep apnea. Anatomic and physiologic interactions.

The distribution of symptoms, physiologic responses, and upper airway structure in members of one family with three generations of subjects with sleep apnea (SA) is reported. Questionnaire data were obtained from ten family members (ages 7 to 66 years), overnight sleep studies were performed in nine subjects, and ventilatory responses to hyperoxic hypercapnia and to eucapnic hypoxia and cephalometry were obtained in five subjects. All ten family members reported habitual snoring or nighttime snorting/gasping; five of ten family members also reported excessive daytime sleepiness. All studied subjects except for a pregnant woman had greater than ten apneas/hypopneas per hour. Ventilatory responses to hypoxia were markedly reduced in all five subjects studied (less than or equal to 0.51 L/min/SaO2); hypercapnic responses were reduced in three of five subjects (less than or equal to 0.61 L/min/mm Hg CO2). No subject was morbidly obese (body mass index less than 29 kg/m2) or demonstrated retrognathia. The posterior airway space was reduced in three subjects, and the mandibular to hyoid distance was increased in four subjects. The two subjects with the longest soft palates and the most inferiorly displaced hyoids had the most severe sleep disorder. Sleep apnea was present, albeit less profound, in the one subject with normal anatomy who had an abnormal hypoxic ventilatory response. The distribution of these physiologic and anatomic measurements in this family provides further support for a genetic basis for SA, and suggests that the disorder may occur as a result of interactions between ventilatory control abnormalities and anatomic risk factors.

Adult↗
PubMed1989

Rapid development of cor pulmonale following acute tonsillitis in adults.

We describe two adult patients in whom acute tonsillitis resulted in the rapid development of cor pulmonale in the absence of clinically evident upper airway obstruction or diffuse obstructive airway disease. Both patients had developed symptoms of sleep apnea and all-night polysomnography confirmed the presence of severe obstructive sleep apnea. These cases emphasize the potentially severe cardiovascular consequences of acute tonsillar hypertrophy in the obese adult patient.

Acute Disease↗
PubMed1989

Massive epistaxis from nasal CPAP therapy.

A 75-year-old man with obstructive sleep apnea and secondary right heart failure was started on nasal CPAP therapy. Shortly thereafter he experienced massive life-threatening epistaxis requiring nasal packing and hospitalization. The epistaxis was thought to be due to the drying effect of nasal CPAP.

Aged↗
PubMed1989

Depression as a manifestation of obstructive sleep apnea: reversal with nasal continuous positive airway pressure.

Fifty-five patients with obstructive sleep apnea each completed a Zung Self-Rating Depression Scale (SDS), Twenty-five patients (45%) had SDS scores greater than or equal to 50, consistent with depression. The SDS scores did not correlate with age, the number of respiratory events per hour sleep, antihypertensive medication, or the oxygen saturation baseline or nadir. The group with SDS scores of 50 or greater, however, had 68.0 +/- 8.8 respiratory events per hour compared with 47.9 +/- 4.7 in the group with SDS scores under 50 (p less than .05). Nineteen patients who were treated with nasal continuous positive airway pressure completed a follow-up SDS Inventory. After treatment, the SDS scores fell from 60.5 +/- 1.9 to 44.4 +/- 2.6 (p less than .001) in the 11 patients with baseline elevated scores. The authors conclude that obstructive sleep apnea can produce prominent symptoms of depression that appear to be related to the severity of the underlying apnea; furthermore, treatment of obstructive sleep apnea may result in alleviation of these symptoms in certain patients.

Adult↗
PubMed1988

Spectral analysis of ventilation in elderly subjects awake and asleep.

We studied the periodicities of ventilation in elderly subjects using digital comb filtering. Two groups of subjects were studied, those with and without sleep apnea. Measurements were made in wakefulness, stage 1-2 sleep, and where possible in stage 3-4 sleep. For each of the digital filters we calculated the average power of the oscillatory output. To compare subject groups we first specifically determined the average power in the filter with the maximum output. The mean of this measurement was greater in elderly subjects with apnea compared with those without apnea, both during wakefulness and stage 1-2 sleep. In both groups of subjects the cycle time of the major ventilatory oscillations was on the order of 40-60 s. There was no difference in this cycle time between the two groups of subjects in wakefulness or stage 1-2 sleep. Thus, whereas similar oscillatory processes occur in subjects with and without apnea, it is the magnitude of the oscillation that differs between the two groups. These conclusions are supported by analysis of the output of individual filters of the digital comb filter. In both groups, stage 1-2 sleep produced significantly increased oscillations in ventilation. Both in wakefulness and stage 1-2 sleep, significantly greater periodicities occurred in the apneic compared with the nonapneic group. In the few subjects who had sufficient data in stage 3-4 sleep for spectral analysis, ventilatory oscillations were virtually absent in this state. Our data suggest that subjects who develop apnea during sleep have an increased propensity for periodic breathing even while awake.

Aged↗
PubMed1988

Changes in compartmental ventilation in association with eye movements during REM sleep.

The effect of phasic eye movement activity on ventilation during rapid-eye-movement (REM) sleep was studied in seven healthy young adults by use of the respiratory inductive plethysmograph. Mean ventilation (VE) and ventilatory components during REM sleep were not significantly different from that seen in either stages 1-2 or 3-4 sleep. The percent of rib cage contribution to ventilation in REM sleep, 29.3 +/- 5.1%, was reduced compared with 54.4 +/- 5.8% in stage 1-2 and 52.2 +/- 4.3% in stage 3-4 sleep (P less than 0.005). When one separated breaths by the degree of associated phasic eye movement activity, it became apparent that breathing during REM sleep is very heterogeneous. Increasing eye movement activity was associated with inhibition of ventilation with a reduction in VE from 5.1 +/- 0.3 to 3.8 +/- 0.3 l/min. Tidal volume and frequency both fell, whereas inspiratory duration was unchanged. Compartmental ventilation was also affected, with the fall in the rib cage contribution from 37.8 +/- 6.4 to 15.3 +/- 5.6%. Chest wall and abdominal movement became more asynchronous as phasic-eye-movement activity increased and frank paradoxical breathing was seen.

Adult↗