Sleep Apnea Evaluation in Lafayette, LA

Sleep apnea is a dangerous, potentially life-threatening condition. It is characterized by interruptions of breathing during sleep. The tongue relaxes during sleep and collapses on the airway. These periodic obstructions of breathing during sleep can compromise a good quality of life and are related to other serious medical conditions such as excessive daytime sleepiness, depression, high blood pressure, heart attack and stroke. It occurs in all age groups including children, but is most prevalent in older adults. Sleep apnea is a disorder unique to human beings. Speech is a special characteristic that distinguishes humans from lower animals. The articulation of speech requires a compliant, collapsible airway. The throat or pharynx is the compliant part of the airway that facilitates speech in humans, and collapses in sleep apnea. Air passes through the nose, mouth and pharynx on its way to the lungs. The pharynx is the conduit for two life supporting functions – swallowing and breathing. Breathing cannot occur simultaneously with swallowing in adult human beings. Normally the muscles of the pharynx maintain the open airway and close it only during swallowing and regurgitation. The exception is sleep apnea, a condition where the pharynx and tongue malfunction, collapse the airway and interrupt breathing during sleep.

Some apneic events can last 60 seconds or longer. Think of the consequences to the brain and heart of an 80 – 100% reduction of oxygen for 30 – 60 seconds. 40 apneic events per hour is classified as “severe” and some patients have apnea-hypopnea indexes in the range of 80 – 100 per hour. Obstructive sleep apnea has very dangerous health consequences.

Obstructive sleep apnea (OSA) is defined as an episode of airflow interruption during sleep, characterized by normal breathing effort but no airflow, lasting longer than 10 seconds (approximately two breaths) and with a minimum of five such episodes per hour. Obstructive sleep apnea occurs only during sleep and not during wakefulness.

Obstructive sleep apnea results from a complex interaction between nerves, muscles and certain predisposing structural anatomic factors. There is a normal relaxation in muscle tone during sleep but with any combination of the above factors in susceptible individuals, the airway closes. The brain then senses a reduction in oxygen and an increase in carbon dioxide and sends a signal to resume breathing. The patient experiences an arousal from sleep in response to the brain signal, and the muscles of the tongue and pharynx open the airway and breathing resumes. Often this occurs with a loud snort or gasp.

Hypopnea The arousal from sleep is necessary to restart breathing, but prevents the patient from getting good quality sleep; and repeated episodes over the course of a night result in such symptoms as excessive daytime sleepiness, compromised immune system, poor concentration, memory problems, a slow reaction time and the medical problems mentioned previously.

Hypopnea is a partial airway obstruction during sleep, in which there is breathing effort but reduced airflow. There must be at least a 50% reduction in normal airflow for at least 10 seconds and more than five per hour. To be scored as a hypopnea, an event must also be accompanied by a de-saturation (a drop in blood oxygen of at least 3%). Hypopneas also result in arousals and symptoms similar to obstructive sleep apnea.

Central Apnearesults when the brain fails to signal the chest muscles to breathe. A defect in the metabolic control center does not respond properly to carbon dioxide in the blood and shuts down the breathing effort. A 10 second or greater episode of no breathing effort and no air flow defines central apnea. Central apneas cause arousals from sleep. In the temporarily awake state, normal respiratory effort resumes.

Upper Airway Resistance Syndrome (UARS) is defined as a decrease in inspiratory effort caused by a lack of muscular activity and reduction in airway size resulting in arousals from sleep without episodes of apnea or hypopnea, and usually characterized by snoring. Patients with UARS have increased respiratory efforts with frequent arousals and without overt apneas. The fragmented sleep results in increased subjective and objective daytime fatigue and less commonly daytime sleepiness. The presence of snoring implies an elevated level of upper airway resistance. Snoring is not, however, synonymous with UARS. Non-apneic snoring does not automatically imply sleep fragmentation.

UARS patients who report nocturnal awakenings feel that is difficult to return to sleep following an arousal. UARS patients seem to have systolic blood pressure less than 105 mm Hg. Hypertension is only a symptom of UARS but a common symptom of OSA. Somatic functional complaints such as muscle pain, fainting and cold hands and feet are all related to UARS. Upper Airway Resistance can be identified on polysomnographic study by the curve of respiratory and expiratory air flow through the nasal/oral canula.

Twenty-four percent of adult men and nine percent of adult women, or more than 20 million Americans, are estimated to have some degree of obstructive sleep apnea. Of these, six million are estimated to have cases severe enough to warrant immediate therapeutic intervention. However, obstructive sleep apnea was not well understood or recognized by primary care physicians until recently, and only a fraction of these 20 million obstructive sleep apnea patients have been diagnosed and treated by a physician. The National Sleep Association estimated that the number of patients currently undergoing treatment is probably less than 500,000.

While obstructive sleep apnea is commonly associated with obesity and male gender, it really affects a broad cross-section of the population. A very significant risk factor is habitual snoring. Unfortunately, results of a recent study indicate that one in three men and nearly one in five women who habitually snore suffer from some degree of obstructive sleep apnea.

Gender

More men than women appear to have sleep apnea. A range of studies has reported apnea or hypopnea (shallow nighttime breathing) in 9% to 25% of men and 4% to 15% of women. Sleep apnea may be under-diagnosed in women, particularly in older women. In general, older women have the same incidence as men their own age. It is not clear why apnea occurs more often after menopause. Although women tend to gain weight and develop larger necks after menopause, a 2001 study suggested that these factors were not the only reason for the increase in sleep apnea in postmenopausal women.

Age

Sleep apnea is most common and its symptoms are worse in middle-aged adults (between 40 and 60 years old). Nevertheless, it affects people of all ages, and, in fact, has been reported in between 1.6% to 3.4% of children. Some experts believe that sleep-disordered breathing may occur in as many as 11% of children. Ethnicity African Americans face a higher risk for sleep apnea than any other ethnic group in the United States. Other groups at increased risk include Pacific Islanders and Mexicans.

Geography

According to one study, although urban dwellers are more likely to report disturbed sleep, particularly as a result of stress, rural dwellers have a significantly higher risk for apnea. It has been Dr Moses’ experience that gender, age, ethnicity and geography are really poor predictors of an apnea patient. While the health history and examination are more important predictors of the possibility of apnea, the only true indicator of apnea is a polysomnographic (sleep) study.

Sleep apnea results from a very complex interaction between anatomic, hormonal, neurological, muscular and postural factors. Sleep apnea is a very dangerous disease, because if left untreated it gets progressively worse and has serious health consequences. Certain of the morbid consequences of sleep apnea are a direct result of the obstruction to breathing, some are effects of sleep deprivation, some are hormonal and others result from the changes caused by reduced oxygen getting to the brain.

Excessive daytime sleepiness. The most prevalent and disturbing side effect of sleep apnea is excessive daytime sleepiness (EDS). Patients suffering from EDS are at high risk for automobile accidents, occupational accidents, and poor work performance. Drowsiness was a factor in over 200,000 car crashes, 76,000 injuries and 1,400 deaths in motor vehicle accidents in the year 2000. The odds of having an auto accident are 3 times greater in drowsy drivers. Six states have passed or have legislation pending that a person driving drowsy is subject to reckless homicide felony laws, carrying a prison sentence of 3 – 28 years if found guilty.

Sleep apnea affects the heart . When breathing stops during apnea episodes carbon dioxide levels in the blood increase and oxygen levels drop. This sets off a cascade of physical and chemical events. Nitric oxide causes blood vessels to remain elastic, but sleep apnea causes decreased levels of nitric oxide and thus less elasticity in blood vessel walls.

One recent study showed that the greater the number of nightly apnea episodes a person had, the more likely they were to develop hypertension in the order of four years. Blood pressure fluctuates widely and rapidly in response to episodes of apnea and hypopnea. This is an autonomic nervous system response that controls involuntary muscle activity such as the heart. The transient constriction of blood vessels controlling the heart can lead to sustained hypertension (high blood pressure) and eventual heart damage. The blood in people with sleep apnea has higher levels of plasminogen. This substance causes the blood to become more viscous or sticky, and is thus more apt to clot and cause strokes. Certain immune factors as well are high in the blood of apnea patients. Immune responses cause inflammation that can damage blood vessels. The white blood cells of apnea patients have an increased number of adhesion molecules. These can bind to the blood vessel linings and also cause inflammation. Inflammation of the blood vessel walls has been implicated in coronary artery disease and heart attacks.

Studies in older people with sleep apnea and excessive daytime sleepiness demonstrate lower test scores for cognitive function. In one study 32% of adult apnea patients also had suffered from depression. Studies of children and adolescents with sleep apnea reported academic underachievement, short attention span, and hyperactivity, all thought to be a result of sleepiness.

The National Commission on Sleep Disorders Research estimates that sleep apnea results in 38,000 cardiovascular deaths each year.

Obstructive sleep apnea and snoring pose difficult and complex issues to healthcare clinicians. No single regimen currently in use is successful on all patients. Each treatment modality has its successes and its not so successful results. OSA, if untreated will not get better and it will get worse. The life threatening morbidity of obstructive sleep disorders means the one alternative that is not acceptable is ignoring the problem. There are three recognized treatment modalities in the domain of medical practice 1) continuous positive airway pressure, 2) surgery and 3) lifestyle changes. In the domain of dentistry there is another modality that is safe, painless, noninvasive and rapidly gaining in popularity – oral appliances.

Continuous Positive Airway Pressure (CPAP) is the most common long term treatment recommended for obstructive sleep apnea, hypopnea, upper airway resistance syndrome, snoring and even central apnea.

The patient wears a mask over their nose, or nose and mouth during sleep. The CPAP machine blows air via a tube through the mask, and the pressure is adjusted to a level sufficient to prevent the airway from collapsing during sleep. Polysomnography is used to set the appropriate CPAP level during a night’s sleep at the sleep lab. The advantage of CPAP is that it almost always works, its cost is reasonable and it is easily titrated. One of the few contraindications is a patient with complete nasal blockade. Among its disadvantages are that patient compliance is low. It is difficult to travel with CPAP, it seems to be a deterrent to sex life, the mask is often uncomfortable, The masks can develop air leaks, skin can become irritated from the mask, excessive morning dry mouth is possible, some complain of abdominal bloat and noise of the pump is obtrusive.

TRDs utilize the suction generated into a rubber bulb to actively pull and hold the tongue into a forward position protruding beyond the incisor teeth. The lower jaw, which is attached to the tongue, is passively pulled forward. Because the mouth must be sealed around the TRD to sustain the necessary suction, its use is absolutely contraindicated in patients who are mouth breathers. A patent nasal airway is a cardinal principle in prescribing a TRD.

Some apneic events can last 60 seconds or longer. Think of the consequences to the brain and heart of an 80 – 100% reduction of oxygen for 30 – 60 seconds. 40 apneic events per hour is classified as “severe” and some patients have apnea-hypopnea indexes in the range of 80 – 100 per hour. Obstructive sleep apnea has very dangerous health consequences.

MADs are fabricated over the teeth so the lower jaw is held more open and protrusive than in the normal biting position. In the MAD the mandible is actively pulled forward and the anterior repositioning of the tongue is passive. Scientific studies have demonstrated that MADs dilate pharyngeal muscles, thus helping prevent collapse of a drooping soft palate. The modified jaw position in a MAD raises the hyoid bone relative to cranial base and extends the neck to a position similar to the one in which CPR is initiated, thus helping maintain an open airway. MADs lower elevator muscle activity, reducing clenching and preventing bruxism. They increase volume of space for the tongue in the mouth. Further, some MADs correct dysfunctional swallowing and some have been shown to increase nasal airflow.

Both MADs and TRDs have advantages and disadvantages. At the present time there are over fifty different mandibular advancement devices available for dentists to choose from. No one yet is the perfect device. MADs are generally more comfortable and better tolerated by most patients than TRDs. MADs can be made for patients with nasally compromised breathing. The overwhelming majority of oral appliances currently being prescribed for apnea and snoring are MADs.

Whichever oral appliance is prescribed for OSA and snoring, as with all other alternative treatment regimens, there is no guarantee of success. Various home monitors are available to objectively evaluate progress each time the device is adjusted. After the dentist has adjusted the oral appliance to maximum performance a final study should be done in the sleep lab to confirm results. The gold standard is still polysomnography.

Oral appliances are not always as effective as CPAP. The importance of titration adds to the cost. Because it is time consuming for the dentist to repeatedly adjust and then measure outcome each time, their cost may be higher than CPAP.

There are side effects to the use of oral appliances. There is an initial accommodation period of getting used to sleeping with a foreign device in the mouth. Symptoms such as tooth discomfort and excessive salivation are common. In the morning when the appliance is removed, there is often a period of 15 – 45 minutes necessary for the jaw to reprogram itself from the forward bite to the habitual bite. Occasionally, there is some tooth movement and bite change as a side effect. Rarely are they serious enough to discontinue using the appliance, but regular, semi-annual check-up visits to the dentist are important.

One problem with oral appliances is that dental work done after fitting and adjustment has been completed may seriously compromise fit and function. Major dental work done subsequent to fitting the appliance could necessitate a remake. Any anticipated dental work should be done before fabrication of an oral appliance for snoring and/or apnea.

Positive lifestyle changes do work, but based on the human psyche, they are difficult to maintain and keep. They require a strong lifetime commitment. They should be utilized, but in perspective to each patient. They usually are most effective as augmentation to other physical regimens.

• No alcohol– alcohol relaxes the muscles of the upper airway during sleep
• No sedatives – sedatives also relax the muscles of the upper airway during sleep, thus facilitating airway collapse
• Eliminate the source of nasal congestion – irritants and allergens can stimulate an allergic reaction, swelling nasal membranes and blocking nasal airflow
• No smoking – smoking causes inflammations and swelling of the upper airway which restricts airflow.
• Regulate sleep hours – the body regulated by a circadian rhythm cycle, a natural internal body clock; there are patterns of brain wave activity and hormone regulation and regeneration that depend on cues given by the biological clock; upsetting these rhythms can disrupt normal biological function and distress the entire system
• Weight loss – excessive weight causes deposition of fat in the pharyngeal tissue, adding to a narrower airway passage and increased chance of collapse
• Sleep on the side – in some patients the apnea or snoring only occurs when they sleep on their back; there are some physical devices of the market to help but retraining sleep position to the side is of major importance

The goal of surgery is to prevent the airway from collapsing during sleep. The many different surgical procedures are directed at increasing airway size and stiffness, eliminate excess tissue in the airway, and correcting jaw deformities that predispose or contribute to compromised airway function.

The key to success is to correctly identify before surgery, the tissue that is causing the airway collapse so the correct procedure can be performed. At this point in the state of the science surgery by most estimates is successful at eliminating OSA 40 – 50% of the time. More than one procedure is often tried before the patient perceives any benefit.

There is debate in the medical literature whether OSA is an anatomic problem or not. Some academics argue that upper airway obstructers are not essential to have apnea. Their position is that apnea is based on a reduced neural compensation by the brain that initially lowers the muscle activity before the actual airway collapse. To strengthen their case they point out that all people with narrow airways and large tonsils get apnea. They believe that is why surgery is not more successful. The focus of their research is directed at optimizing neural drive to the muscles that maintain airway patency during sleep. “Keep the airway awake and let the brain sleep” is their operative goal.

Certainly apnea and snoring are difficult and complex problems. No regimen currently in use is successful on all patients. Each treatment modality has its successes and its not so successful results. OSA, if untreated will not get better and it will get worse. The life threatening morbidity of obstructive sleep disorders means the one alternative that is not acceptable is ignoring the problem.

Decisions on treatment are customized for each patient based on the medical history, sleep specialist’s examination, results of the sleep lab study, the individual’s unique needs, preferences, health problems and life style. Success of the selected treatment can and should be verified by a repeat study in the sleep lab.

There are two main categories of oral appliances – Tongue Retaining Devices (TRDs) andMandibular Advancement Devices (MADs). Both result in the tongue being in a more forward position than normal and the mouth being held open beyond its normal rest position. They presumably keep the airway open by preventing collapse of the tongue on the soft palate and throat.