"The doctor says my son had 86 respiratory events during his sleep study, all of which were hypopneas and not apneas." What's the difference?
"a" -- meaning "not"
"hypo" -- meaning "below"
"pnea" -- meaning "to breathe"
A + pnea (apnea) [ap-nE-uh] = not breathing
Hypo + pnea (hypopnea) [hI-pop-nE-uh] = shallow breathing
"oxia" -- oxygen
Hypo + oxia (hypoxia) [hI-pok-sE-uh] = too little oxygen (O2) in the blood
"hyper" -- above, high
"kapnos" -- "smoke" (here meaning "carbon dioxide")
Hyper + capnia (hypercapnia)
= too much carbon dioxide (CO2) in the blood
People with Duchenne and many other neuro-muscular diseases (NMDs) will face "hypopnea" (shallow breathing) as the disease progresses. Though often diagnosed as "hypoxia" (lack of oxygen in the blood), the true challenge most people will face if they have Duchenne, ALS, SMA, polymyositis, a high level spinal chord injury (SCI), or many other conditions is hypopnea. Generally, hypopnea will first affect breathing while asleep.
The person may not be directly aware of his breathing problem, and it may first be diagnosed during a hospital stay. However, by then he has probably already been showing the symptoms for quite some time, symptoms including...
For the person with an NMD or SCI, the cause of her breathing problem is usually...
Doctors often prescribe "supplemental O2" (oxygen) to correct the hypoxia; however, the problem is not the hypoxia, that is only a symptom of the shallow breathing. If the weak respiratory muscles cannot be directly addressed (as in Duchenne, NMDs, and SCI), we must address the next level up--the shallow breathing--by providing respiratory assistance (a ventilator) during periods of hypopnea. Often, for the person with a neuro-muscular disease, this is initially only a problem at night when she cannot consciously take a deep breath.
Supplemental oxygen should not be used to "correct" low blood oxygen saturation (hypoxia) in Duchenne patients or others with an NMD or SCI without first checking for hypercapnia and hypopnea. The improper use of supplemental oxygen has many bad side effects including masking congestion that requires "assisted coughing" to get cleared out to prevent pneumonia and other problems. And, improper use of supplemental oxygen can cause breathing to slow or even stop.
According to Dr. Bach and others, the correct course to take for these hypopneic patients is to investigate the use of nocturnal NIV/IPPV--nighttime noninvasive intermittent positive pressure ventilation.
Please see Dr. Bach's Outpatient Protocol regarding SaO2 monitoring, assisted coughing, and NIV/IPPV, and Prevention of Pulmonary Morbidity in Duchenne Muscular Dystrophy for more information and supporting research.
Pronunciation guide: The CAPITAL vowels mean to pronounce a "long" vowel (hI=high, pO=poe, nE=knee, etc.).
Dr. Bach's Articles: ©2000-2004, John R. Bach, MD, used by permission.
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