Obstructive Sleep Apnoea

OSA Treatments

The treatment options for OSA can be split depending on the severity. For severe OSA Continuous Positive Airway Pressure (CPAP) is the clear gold standard treatment, with the highest clinical success. MAS therapy tends to be the treatment of choice for mild to moderate Obstructive Sleep Apnoea as it very effective, less expensive and more patient friendly compared to CPAP.

Sleepwell ™ can be offered in conbination with CPAP as it holds the lower jaw forward thereby opening the airway hence reducing the air pressure required. Patients who have a low CPAP compliance threshold should be considered for Sleepwell ™.

There are two well established clinically proven treatment options :-

Intra-oral appliances

Mandibular advancement splints (MAS)

The MAS is by far the most common form of intra-oral appliance used in the management of SBD (Schmidt-Nowara et al., 1995; Johal and Battagel, 2001). There is considerable variation in the design of MAS, but all posture the mandible forwards, to a varying extent, with a degree of vertical opening. Sleepwell ™ is the most clinically proven and effective.

Nasal continuous positive airway pressure (N-CPAP)

N-CPAP is regarded as the major non-surgical, long-term treatment; the so-called 'gold standard'. Described by Sullivan et al. (1981), N-CPAP delivers a continuous stream of filtered air under low pressure (5 to 15cm H2O) through a nasal mask to the pharynx. N-CPAP acts as a pneumatic splint, by raising the intra-luminal pressure in the upper airways, preventing them from collapsing regardless of the subjectÍs position, but not enough to prevent expiration. All subjects undergo full polysomnographic studies in order for N-CPAP titration to be performed, to ensure that the pressure used is sufficient for maintaining airway patency and preventing apnoea in all sleep stages and postures. Most patients require lifelong treatment and to be reliably effective, N-CPAP should be used for 4 to 6 hours per night, 7 days a week (Engleman et al., 1998). The reported benefits of N-CPAP are: improved quality of life (Sanner et al., 2000); improved daytime cognitive function (Borak et al., 1996); elimination of snoring, and other night-time symptoms and reversal of daytime symptoms, in particular, sleepiness (Kiely et al., 1999) and reduced risk of road traffic accidents (Hack et al., 2000); long-term improvement in survival rates near to those of the general population (Chaouat et al., 1999). In addition, many of the beneficial effects have been shown to continue over the longer-term (Jenkinson et al., 2001). N-CPAP is the treatment for OSA with the firmest evidence base (Wright et al., 2002). However, randomised controlled trials of treatment for mild OSA do not support reduced objective sleepiness after N-CPAP and thus this should be reserved as a first line choice of therapy for those with moderate or severe OSA (Jenkinson et al., 1999; Barbe et al., 2001).

However, the use of N-CPAP is not without its problems: long-term compliance has been estimated at between 60 to 95 per cent, with intensive efforts (Engleman et al., 1998; McCardle et al., 1999); problems are often encountered with the nasal mask (Pepin et al., 1995); the face mask is considered anti-social and the machine noisy (Engleman et al., 1998). In an attempt to overcome some of the problems with N-CPAP, auto-titrating devices have been developed which raise pressure if they detect upper airway narrowing or obstruction and, conversely, lower pressure if the airway is not obstructed (Lloberes et al., 1996). However, they are more expensive than conventional N-CPAP machines and, as yet, there is no convincing evidence that they produce better outcomes in managing OSA over the long-term.

Elimination of aggravating factors

Regardless of the severity of the SBD, it is prudent to eliminate co-existent conditions that either predispose to or worsen upper airway dysfunction during sleep (see section 2.3.3). Subjects should therefore abstain from alcohol and caffeine during the evening, avoid the use of central nervous system depressants and ensure adequate control of any co-existing chronic obstructive airway disease, asthma or hypothyroidism. Furthermore, in subjects with a BMI above 25, research has demonstrated a weak correlation between the amount of weight loss and the clinical response (Smith et al., 1985; Kuna and SantÍAmbrogio, 1991). A Cochrane review of lifestyle modifications for subjects with OSA could not identify any randomised controlled trials to support their use and concluded that there was no strong evidence to prevent instituting therapies of proven effectiveness, such as N-CPAP (Shneerson and Wright, 2002).

Changing sleeping posture

Research has demonstrated that, in a proportion of subjects, the frequency of SBD is substantially greater during sleep in the supine position compared with the lateral recumbent position (Cartwright, 1984). That author proposed that the effect of gravity on the tongue and enlarged soft palate collectively could lead to upper airway occlusion. Methods used to help subjects to sleep in the lateral recumbent position include the use of a tennis ball sewn into the back of their sleeping garment and positional alarms. In subjects whose symptoms are enhanced in the supine position, such treatment modalities have been demonstrated to reduce the AHI by 50 per cent (Cartwright et al., 1991).

Removal of nasal obstruction and nasal dilating devices

The presence of any nasal obstructions (see section 2.6.2) will lead to an increase in nasal airway resistance, which in turn will further promote collapse of the upper airway during inspiration. Despite the unpredictable direct effects of relieving nasal obstruction on SBD (Elsherif and Hussein, 1998), some authors suggest the removal of any obstructions as first line care in facilitating other treatment regimes (Kuna and SantÍAmbrogio, 1991). The use of external nasal dilating devices to reduce nasal resistance has been shown to have beneficial effects in reducing the severity of snoring (Hoffstein et al., 1993; Ulfberg and Fenton, 1997).

Pharmacological therapy

The limited data available suggests that protriptyline (a non-sedating tricyclic anti-depressant) may be associated with a reduction in apnoeic episodes and daytime sleepiness (Clark et al., 1979; Bronwell et al., 1982). This may occur as a result of its REM-sleep suppressant effect or augmentation of upper airway muscle tone. However, the trials carried out have involved only a small number of subjects and the drug's anti-cholinergic effects are also limiting as they may exacerbate any cardiac problem. Smith et al. (2002), in their Cochrane review, concluded that no medication demonstrated a consistent response. Thus, the evidence base to date does not support the use of pharmacological therapy as effective first line therapy for OSA. More recently, however Modafinil, a wake provoking agent, has been shown to be an effective and well tolerated adjunctive therapy for the treatment of residual daytime sleepiness in OSA subjects whose apnoea is controlled by to N-CPAP (Kingshott et al., 2001; Schwartz et al., 2003).

In addition a range of surgical procedures address snoring however success varies. Short term results using surgical procedures have shown limited success, the long term results show that the snoring can return. Procedures include Tracheostomy, Nasal surgery, Pharyngeal surgery, Maxillo-facial surgery and Tongue base resection. In summary Uvulopalatopharyngoplasty (UPPP) is proven to be 50-90% successful for snoring but problems with the procedure include, pain, nasal regurgitation, swallowing problems and speech disturbances. Laser assisted uvulopalsty (LAUP) is 55-90% successful for snoring with similarly difficult side effect for the patient.