Goodlettsville Dental Services

Mixed Apnea And Complex Sleep Apnea

Some people with sleep apnea have a combination of both types. When obstructive sleep apnea syndrome is severe and longstanding, episodes of central apnea sometimes develop. The exact mechanism of the loss of central respiratory drive during sleep in OSA is unknown but is most commonly related to acid-base and CO2 feedback malfunctions stemming from heart failure. There is a constellation of diseases and symptoms relating to body mass, cardiovascular, respiratory, and occasionally, neurological dysfunction that have a synergistic effect in sleep-disordered breathing. The presence of central sleep apnea without an obstructive component is a common result of chronic opiate use (or abuse) owing to the characteristic respiratory depression caused by large doses of narcotics.

Complex sleep apnea has recently been described by researchers as a novel presentation of sleep apnea. Patients with complex sleep apnea exhibit OSA, but upon application of positive airway pressure the patient exhibits persistent central sleep apnea. This central apnea is most commonly noted while on CPAP therapy after the obstructive component has been eliminated. This has long been seen in sleep laboratories and has historically been managed either by CPAP or BiLevel therapy. Adaptive servo-ventilation (ASV) modes of therapy have been introduced to attempt to manage this complex sleep apnea. Studies have demonstrated marginally superior performance of the adaptive servo ventilators in treating Cheyne-Stokes breathing; however, no longitudinal studies have yet been published, nor have any results been generated that suggest any differential outcomes versus standard CPAP therapy. At the AARC 2006 in Las Vegas, NV, researchers reported successful treatment of hundreds of patients on ASV therapy; however, these results have not been reported in peer-reviewed publications as of July 2007.

An important finding by Dernaika et al. suggests that transient central apnea produced during CPAP titration (the so-called “complex sleep apnea”) is “…transient and self-limited.” The central apneas may in fact be secondary to sleep fragmentation during the titration process. As of July 2007, there has been no alternate convincing evidence produced that these central sleep apnea events associated with CPAP therapy for obstructive sleep apnea are of any significant pathophysiologic importance.

Research is ongoing, however, at the Harvard Medical School, including adding dead space to positive airway pressure for treatment of complex sleep-disordered breathing.

Treatment

The most common treatment for sleep apnea is the use of a continuous positive airway pressure (CPAP) device, which ‘splints’ the patient’s airway open during sleep by means of a flow of pressurized air into the throat. However, the CPAP machine only assists inhaling, whereas a BiPAP machine assists with both inhaling and exhaling and is used in more severe cases.

In addition to CPAP, a dentist specializing in sleep disorders can prescribe Oral Appliance Therapy (OAT). The oral appliance is a custom-made mouthpiece that shifts the lower jaw forward, which opens up the airway. OAT is usually successful in patients with mild to moderate obstructive sleep apnea. Precise control of the position of the mandible is crucial to the success of an oral appliance.

OAT is a relatively new treatment option for sleep apnea in the United States, but it is much more common in Canada and Europe.In Singapore, there is a new treatment.

CPAP and OAT are generally effective only for obstructive and mixed sleep apnea.

In mild cases of obstructive sleep apnea, use of a specially shaped pillow or shirt may reduce sleep apnea episodes, usually by causing users to sleep on the side instead of on the back or in a reclining position instead of flat.

For patients who do not tolerate or fail nonsurgical measures, surgical treatment to anatomically alter the airway is available. Several levels of obstruction may be addressed, including the nasal passage, throat (pharynx), base of tongue, and facial skeleton. Surgical treatment for obstructive sleep apnea needs to be individualized in order to address all anatomical areas of obstruction. Often, correction of the nasal passages needs to be performed in addition to correction of the oropharynx passage. Septoplasty and turbinate surgery may improve the nasal airway. Tonsillectomy and uvulopalatopharyngoplasty (UPPP or UP3) is available to address pharyngeal obstruction. Base-of-tongue advancement by means of advancing the genial tubercle of the mandible may help with the lower pharynx. A myriad of other techniques are available, including hyoid bone myotomy and suspension and various radiofrequency technologies. For patients who fail these operations, the facial skeletal may be advanced by means of a technique called maxillomandibular advancement, or two-jaw surgery (upper and lower jaws). Technically, this is accomplished by a surgery similar to orthognathic surgeries addressing an abnormal bite. The surgery involves a Lefort type one osteotomy and bilateral sagittal split mandibular osteotomies.

Other surgery options may attempt to shrink or stiffen excess tissue in the mouth or throat, procedures done at either a doctor’s office or a hospital. Small shots or other treatments, sometimes in a series, are used for shrinkage, while the insertion of a small piece of stiff plastic is used in the case of surgery whose goal is to stiffen tissues.

Possibly owing to changes in pulmonary oxygen stores, sleeping on one’s side (as opposed to on one’s back) has been found to be helpful for central sleep apnea with Cheyne-Stokes respiration (CSA-CSR).
Medications like Acetazolamide lower blood pH and encourage respiration. Low doses of oxygen are also used as a treatment for hypoxia but are discouraged due to side effects.

Alternative treatments

A 2005 study in the British Medical Journal found that learning and practicing the didgeridoo helped reduce snoring and sleep apnea as well as daytime sleepiness. This appears to work by strengthening muscles in the upper airway, thus reducing their tendency to collapse during sleep.

A program that uses specialized “singing” exercises to tone the throat, in particular the soft palate, tongue and nasaopharynx, is ‘Singing for Snorers’ by Alise Ojay. Dr. Elizabeth Scott, a medical doctor living in Scotland, had experimented with singing exercises and found considerable success, as reviewed in her book The Natural Way to Stop Snoring (London: Orion 1995) but had been unable to carry out a clinical trial. Alise Ojay, a choir director singer and composer, began researching the possibility of using singing exercises to help a friend with snoring and came across Dr. Scott’s work. In 1999, as an Honorary Research Fellow with the support of the Department of Complementary Medicine at the University of Exeter, Alise conducted the first trial of singing exercises to reduce snoring. The results were described by Ojay as promising and after two years of investigations, she designed the ‘Singing for Snorers’ program in 2002.

The independent nonprofit UK consumer advocacy group Which? reviewed Singing for Snorers. Their physician Dr. Williams “feels the company is ethical in ‘offering aims not claims’ until research is complete” and the review stated: “Combining the programme with diet and exercise, the snorer in our test couple found real improvements in the volume and frequency of his snoring after six weeks. His partner is sleeping better, too.” In the case of snorers who also have sleep apnea, there is anecdotal evidence from some of the users of Ojay’s program, as she reports on her page, as reported by an American, Charley Hupp, who flew to the UK to personally thank her, on his web page and as reported by one user in the UK on the discussion forum of the British Snoring and Sleep Apnoea Association. This person reported that sleep tests before and after the program showed a significant effect: “My apnoeas had gone down from 35 to 0.8 per hour.”

Benefits and risks for treatment by surgery

CPAP is functional in sleep apnea and cost-efficient for the health care system, but it is a symptomatic therapy and does not cure the disease. In contrast, although not well known, surgery is more expensive and can treat directly the causes of sleep apnea: The Stanford Center for Excellence in Sleep Disorders Medicine achieved a 95% cure rate of sleep apnea patients by surgery. Maxillomandibular advancement (MMA) is considered the most effective surgery for sleep apnea patients, because it increases the posterior airway space (PAS). The main benefit of the operation is that the oxygen saturation in the arterial blood increases. In a study published in 2008, 93.3.% of surgery patients achieved an adequate quality of life based on the Functional Outcomes of Sleep Questionnaire (FOSQ). Surgery led to a significant increase in general productivity, social outcome, activity level, vigilance, intimacy and sex, and the total score postoperatively was P = .0002. Overall risks of MMA surgery are low: The Stanford University Sleep Disorders Center found 4 failures in a series of 177 patients, or about one out of 44 patients.

Surgery and anesthesia in patients with sleep apnea

Several inpatient and outpatient procedures use sedation. Many drugs and agents used during surgery to relieve pain and to depress consciousness remain in the body at low amounts for hours or even days afterwards. In an individual with either central, obstructive or mixed sleep apnea, these low doses may be enough to cause life-threatening irregularities in breathing or collapses in a patient’s airways. Use of analgesics and sedatives in these patients postoperatively should therefore be minimized or avoided.

Surgery on the mouth and throat, as well as dental surgery and procedures, can result in postoperative swelling of the lining of the mouth and other areas that affect the airway. Even when the surgical procedure is designed to improve the airway, such as tonsillectomy and adenoidectomy or tongue reduction, swelling may negate some of the effects in the immediate postoperative period. Once the swelling resolves and the palate becomes tightened by postoperative scarring, however, the full benefit of the surgery may be noticed. Individuals with sleep apnea generally require more intensive monitoring after surgery for these reasons.

Sleep apnea patients undergoing any medical treatment must make sure his or her doctor and/or anesthetist are informed about their condition. Alternate and emergency procedures may be necessary to maintain the airway of sleep apnea patients. If an individual suspects he or she may have sleep apnea, communication with their doctor about possible preprocedure screening may be in order.