C

FIGURE 3 (See color insert.) (A) Schematic diagram illustrating oral cavity before (left) and after (right) tonsillectomy. (B) Patient's oral cavity depicting hypertrophied tonsils. (C) Same patient's oral cavity following tonsillectomy.

may be obstructed when the child is supine, the tongue falling back and the airway narrowing during REM sleep hypotonia. Also in a growing child the tonsils may also grow larger. If only the adenoids are removed there is the risk of having to later return for further surgery to remove the tonsils. Clinicians should be aware that there are several different techniques used to remove tonsils and this may play a role in the efficacy of treatment.

The anesthesiologist should be familiar with OSA since postoperative pulmonary complications can occur (87). Children with OSA are often thinner than expected. This is may be due to multiple factors including the greater caloric demand of breathing through a narrow airway and possible disruption of growth hormone secretion. Children after OSA surgery may unexpectedly increase their weight (88).

Surgery does not always completely cure the child's SDB. The true cure rate of this surgery for SDB is unknown (23,28,89,90). Most studies that have performed postsurgical sleep studies have used older adult definitions of sleep apnea in the children. Suen et al. designed a prospective study of 69 children aged 1 to 14 years who were referred to an otolaryngologist. Of the 69 children 35 (51%) had a RDI > 5 on polysomnography. Thirty children with a RDI > 5 underwent adenotonsillectomy. Of the 30 children 26 had follow-up polysomnography following surgery. All 26 children had a lower RDI after surgery, although four patients still had a RDI > 5. Using a RDI cut off of 5, the cure rate of surgery would be 85%. However, three children snored with postoperative RDI < 5. If those subjects were considered to have residual SDB then the cure rate of surgery would only be 73%. All patients improved with adenotonsillectomy but the true cure rate is not clear. The possibility of residual SDB should always be considered after surgery if the child is symptomatic. Suen et al. concluded history and physical findings were not useful in predicting outcome (91). Different surgical techniques may improve the success of surgery in these children (92).

Some may argue that patients with clear-cut cases of SDB may skip the postoperative sleep study. However, the adult experience teaches us that it is precisely these obviously more severe or "clear-cut" cases that will have residual disease. Adenotonsillectomy will not change the relationship of tongue size and shape to the palate. The parents may report that the child is "100% better" yet still has residual obstruction. If the child still has trouble paying attention in school, a sleep problem may be overlooked and no longer be considered a possibility. The child may end up labeled as having attention-deficit disorder because there was no postoperative sleep test done (36,93).

CPAP therapy should be considered if surgery is not a viable option for the child (94-96) (Fig. 4). CPAP uses a small air compressor attached to a mask via a

FIGURE 4 (See color insert.) (A) Child awake and (B) asleep while wearing a continuous positive airway pressure mask during polysomnography monitoring in a sleep laboratory. Note wires connected to recording electrodes that are placed on the face and on the scalp, which are hidden beneath the head wraps used to prevent dislodgement of electrodes.

FIGURE 4 (See color insert.) (A) Child awake and (B) asleep while wearing a continuous positive airway pressure mask during polysomnography monitoring in a sleep laboratory. Note wires connected to recording electrodes that are placed on the face and on the scalp, which are hidden beneath the head wraps used to prevent dislodgement of electrodes.

hose. The mask usually only covers the nose but masks are available that cover the nose and mouth. By forcing positive air pressure in the airway, the negative pressure of inspiration can be countered to avoid airway narrowing or collapse. CPAP is effective but can be cumbersome to use. Over time the CPAP devices have become smaller and quieter. The masks have also improved with many more styles and sizes available. In the recent past in the United States there was no CPAP mask certified for home use in children. Clinicians needed to obtain the mask from outside of the country or used the smallest available adult mask. This has now changed. CPAP has been approved for home use in children in the United States. A wider range of mask sizes and styles should now become available.

Despite these advances CPAP remains a second choice over surgery in most children (70). This is due to the advantage of having a surgical option. The main drawbacks of using CPAP are related to getting a proper-fitting CPAP mask. If the mask is not fitted correctly the air pressure may leak out causing discomfort and sleep disruption. If the mask is too tight it can cause facial abrasions or bruising. In small children the possibility of the CPAP mask interfering with growth of the maxilla should be considered. As the child grows CPAP may require adjustments both in terms of mask size and the amount of pressure delivered to the airway. In addition to a continuous pressure delivery mode, a bilevel mode [bilevel positive airway pressure, (BPAP)] is available. In this mode, the pressure on expiration is lowered from the inspiratory pressure (see also Chapter 7). This may allow the device to be more comfortable and may be preferred in patients with neuromuscu-lar weakness. The most recent advance in positive airway pressure has been the development of machines, which can adjust the pressure required to keep the airway open on a breath-by-breath basis. These so-called "smart CPAP" or auto-positive airway pressure units (see also Chapter 8) are promising but are not part of the mainstream treatment of children at this time (94).

The treatment of residual or persistent OSA after surgery is a difficult clinical situation. CPAP has been the recommended option yet CPAP can be cumbersome.

FIGURE 5 (See color insert.) Maxillary osteogenic distraction device placed below the palate of a child's mouth. Source: Photograph courtesy of Kannan Ramar, MD.

If a child has clinically significant SDB after adenotonsillectomy and CPAP is not an option or not tolerated the clinician had been forced to consider more aggressive surgery such as a tracheostomy or palliative use of supplemental oxygen. A search for better alternatives is underway. The application of more sophisticated surgical techniques with the possible use of orthodontic treatments is being pursued (97-100). In adults with persistent sleep apnea after a uvulopalatoplasty the remaining obstruction is often at the level of the base of the tongue. This may be due to a combination of retrognathia and a narrow hard palate. The most effective surgical correction at this level of obstruction is bilateral maxillo-mandibular advancement. This surgery is not advised for the growing bones of young children.

FIGURE 6 (See color insert.) Profile of child's face (A) before and (B) after mandibular distraction osteogenesis.

The base of tongue obstruction can be minimized in some children with rapid maxillary expansion (99,101). By widening the child's palate the tongue can fit into its natural position on the hard palate and be less likely to slide back into the hypopharynx (Fig. 5). This procedure is most effective when there is a significant narrow and high-arched palate. Such osteogenic distraction techniques are very promising. These techniques were traditionally reserved in children with cranio-facial anomalies to lengthen bones. These techniques are starting to be adapted for persistent SDB to bring the mandible forward and increase the posterior airway space in the pharynx (Fig. 6).

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