Sleep Apnea: What Causes it? Weak
Diaphragm Muscles May Be Factor
By LOIS BAKER
News Services Editor
Research on the respiratory system being conducted at UB may shed new light on the causes of sleep apnea, brief episodes during the night when breathing ceases, depriving the brain of oxygen.
Sleep apnea occurs most often among people aged 30 to 40 who are overweight. It can cause excessive sleepiness during the day, which can disrupt work and social life.
Using rats as an animal model, Gaspar Farkas, UB associate professor of physical therapy and exercise science, and colleagues showed that weakened diaphragm muscles, the muscles most responsible for breathing, may be one of the factors contributing to the condition.
The researchers measured diaphragm function in lean and obese rats over a normal 18-month lifetime, testing them when they were young (6-8 weeks), mature (10-12 months) and old (17-18 months). They found that diaphragm muscles in the obese animals lost their ability to respond forcefully as the animals aged. Diaphragm response in the obese young animals was not compromised.
"The diaphragm is the only respiratory muscle that is active
during REM sleep, and in obese people it is already overloaded," Farkas
said. "We have shown that these muscles become weakened with age, at a time
when load and stress on these muscles are already great, so it's a double
deficit. "This finding helps to explain why an obese person may not have
problems with sleep apnea at 20, but may have problems at 50," he
added.Researchers from the University of Florida at Gainesville and the
University of South Dakota also participated in the study.
From Mike: No doubt in mind that weak diaphragms arr a major aspect
of OSA More
about
The Effect of Cervical Circumference, Lingual
Height and Lingual Width on
the Obstructive Sleep Apnea-Hypopnea Syndrome
Chen H,
Zhang X.
Department of Otolaryngology, Haidian Hospital, Beijing, 100080, China.
chenhanent@tom.com
OBJECTIVE: To investigate the relation between the obstructive sleep apnea
syndrome and the metrical value of the patient's cervical circumference,
lingual height and lingual width.
METHOD: The clinical and radiographic data
of 33 (OSAHS) patients were retrospectively analyzed, the value of cervical
circumference was direct manual measurement, the value of lingual height,
lingual width was indirect measured through X-ray radiography of Iodic oil,
and selected 33 normal adult as control group.
RESULT: The mean of cervical
circumference, lingual height and lingual width of OSAHS group have
significant difference to normal control group respectively, the value of
OSAHS group remarkably higher than control group.
CONCLUSION: Cervical
circumference, lingual height and lingual width make important effect on
pathogenesis of OSAHS.
PMID: 16375110 [PubMed - in process]
From Mike:
Makes good sense and is a reason why we work with the tongue and cervical
spine a lot but that is only part of the whole picture.
More
about
Manual Abdominal Compression for the
Detection of Expiratory Flow Limitation
Abdel Kafi S,
Leduc D,
Sergysels R,
Ninane V.
Service de Pneumologie et de Soins Intensifs, CHU Saint-Pierre, Bruxelles,
Belgique. sophia_abdelkafi@stpierre-bru.be
INTRODUCTION: Expiratory flow limitation (EFL) is a characteristic feature
of chronic obstructive pulmonary disease (COPD) and leads to dynamic
hyperinflation (DH) which is a major source of dyspnoea, particularly during
exercise.
STATE OF THE ART: A new technique for the detection of EFL, based
on manual compression of the abdomen (MCA), was assessed both in normal
subjects and patients with COPD. MCA was always associated with a moderate
increase in pleural pressure and allowed the detection of EFL in a
reproducible manner, in both the seated and supine postures. The technique
was well tolerated. It was also a reliable method for the detection of EFL
during exercise since EFL detection was effectively associated with the
development of DH. Finally, MCA was also compared to NEP in patients with
obstructive sleep apnea syndrome (OSAS) and in these patients, MCA
invariably increased expiratory flow whereas the NEP method produced flow
limitation in some cases because of upper airway collapse.
PERSPECTIVES: EFL
detection with MCA may be clinically useful since EFL is a determinant of
dyspnoea, affects ventilatory response to exercise as well as maximum
exercise capacity.
CONCLUSIONS: MCA is a reliable technique for the
detection of EFL in different positions, during resting breathing or
exercise, requiring neither special equipment nor patient cooperation.
PMID: 15968762 [PubMed - indexed for MEDLINE]
From Mike:
Helpful but so much more is needed.
More about
Experimental Physiology
Review Article
doi:10.1113/expphysiol.2005.032268
Volume 0 Issue 0
Mathematical Models of Periodic Breathing and Their Usefulness in Understanding Cardiovascular and Respiratory Disorders
Neil S. Cherniack and Guy S. Longobardo
Periodic breathing is an unusual form of breathing with oscillations in minute ventilations and with repetitive apnoeas or near apnoeas. Reported initially in patients with heart failure or stroke, it was later recognized to occur especially during sleep. The recurrent hypoxia and surges of sympathetic activity that often occur during the apnoeas have serious health consequences. Mathematical models have helped greatly in the understanding of the causes of recurrent apnoeas. It is unlikely that every instance of periodic breathing has the same cause, but many result from instability in the feedback control involved in the chemical regulation of breathing caused by increased controller and plant gains and delays in information transfer. Even when it is not the main cause of the periodic breathing, unstable control modifies the ventilatory pattern and sometimes intensifies the recurrent apnoeas. The characteristics of disturbances to breathing and their interaction with the control system can be critical in determining ventilation responses and the occurrence of periodic breathing. Large abrupt changes in ventilation produced, for example, in the transition from waking to sleep and vice versa, or in the transition from breathing to apnoea, are potent factors causing periodic breathing. Mathematical models show that periodic breathing is a 'systems disorder' produced by the interplay of multiple factors. Multiple factors contribute to the occurrence of periodic breathing in congestive heart failure and cerebrovascular disease, increasing treatment options.
From Mike: Clearly one major factor is UDB
WHERE THEY WENT WRONG I BELIEVE?
The Effect of Treatment on Diaphragm Contractility in Obstructive
Sleep Apnea Syndrome.
El-Kabir DR,
Polkey MI,
Lyall RA,
Williams AJ,
Moxham J.
Lane Fox Respiratory Unit and Sleep Disorders Centre, St Thomas'
Hospital, Guy's King's and St Thomas' School of Medicine, Lambeth Palace
Road, London SE1 7EH, UK. desielk@cwcom.net
In untreated obstructive sleep apnea syndrome (OSAS) inspiratory efforts
are made against an occluded airway and diaphragm fatigue might
therefore complicate OSAS. To test this hypothesis we measured twitch
transdiaphragmatic pressure (Tw Pdi) in response to bilateral cervical
magnetic stimulation of the phrenic nerve roots in nine patients with
OSAS before and one month after successful therapy with nasal continuous
positive airways pressure (nCPAP). The mean Tw Pdi before therapy was
23.2cm H2O and after therapy was 22.8cm H2O (P = 0.59); the mean change
after initiation of nCPAP was 0.4cm H2O with 95% confidence intervals of
-1.3cm H2O and +2.1 cm H2O. We conclude that low frequency diaphragm
fatigue does not complicate untreated OSAS
From Mike: My theory is that properly developing the diaphragm as well as the vocal tract will eliminate most if not all OSA. Begin here
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