The use of nasal continuous positive airway pressure to treat obstructive sleep apnoea.

AIM: To review 66 children with obstructive sleep apnoea (OSA) for whom a trial of nasal continuous positive airway pressure (nCPAP) was proposed. METHODS: Baseline sleep studies were performed to assess OSA severity; a trial of nCPAP was performed where moderate to severe OSA, not relieved by adenotonsillectomy, was found. The nCPAP trial was considered either technically successful (ST), if the child accepted the mask for sufficient time to determine nCPAP efficacy, or a technical failure (FT) if otherwise. Patients with an initial FT were offered a period of home acclimatisation to familiarise them with wearing the mask during sleep. ST patients in whom nCPAP was effective were established on long term therapy. RESULTS: Nasal CPAP trials were successful (ST) in 49/66 (74%) patients. Nasal CPAP efficacy could not be determined in the remaining 17 FT patients (26%), generally because of their poor nCPAP tolerance. These patients were subsequently considered for other treatment. A total of 42/49 (86%) ST patients were established on long term nCPAP therapy, 2/49 (4%) derived no benefit from nCPAP, while 5/49 (10%) refused long term nCPAP therapy. Of patients on long term nCPAP, the most frequently reported side effects were skin irritation and nasal dryness; however, these were not serious enough to require any patients to discontinue therapy. A period of home acclimatisation was found to be effective in increasing nCPAP acceptance, with 26% of FT children being subsequently successfully reassessed for nCPAP. CONCLUSION: The use of nCPAP was feasible in a significant proportion of a paediatric OSA population. Failure was usually because of the child's intolerance of the nCPAP equipment. Nasal CPAP was an effective treatment in the majority of patients where it could be assessed, and was adopted as a long term therapy in most cases. We have successfully used nCPAP to treat OSA across a wide range of ages. Motivated parents and skilled support staff have proved essential for the success of nCPAP in a paediatric setting.

Breathing patterns in children with craniofacial dysostosis and hindbrain herniation.

In the past few years, hindbrain herniation has become recognized as a frequent feature of the child with syndromic craniofacial dysostosis. The clinical significance of hindbrain herniation in these disorders is unclear. Abnormalities of respiratory control have frequently been reported. The aim of the present study was to document the incidence of obstructive and central respiratory abnormalities during sleep in craniofacial syndromes with hindbrain herniation. We performed cardiorespiratory sleep studies during unsedated night-time sleep in a group of 13 children. Hindbrain herniation was confirmed by magnetic resonance imaging (MRI) and ranged 1.5-26.9 mm below the cranial base. Sleep studies revealed central respiratory pauses associated with important reduction of the arterial oxygen saturation (Sa,O2) in only two of 13 cases (minimum Sa,O2 86% and 87%). In contrast 10 of 13 children had some degree of upper airway obstruction (four mild, three moderate and three severe). Of the remaining three children, two had previous long-term tracheostomies. Changes in the breathing pattern were proportional to the severity of the obstruction and comprised increased respiratory efforts and arterial oxygen desaturation. Infrequent mixed apnoeas were observed in five patients, and their severity reflected the severity of the obstructive component. In conclusion, obstruction of the upper airways was the predominant sleep-related respiratory problem in this group of patients. Hindbrain herniation was not associated with a high incidence of central sleep apnoea.

Consequences of cranial vault expansion surgery for craniosynostosis.

Remodelling the cranial vault in an attempt to increase the intracranial volume and thus control intracranial hypertension, whilst at the same time improving the patient's appearance, has been the mainstay of surgery for syndromic craniosynostosis. We report a case of craniosynostosis in whom cranial vault expansion was followed by the development of hind-brain herniation and hydrocephalus. This prompted a review of our other cases of craniosynostosis who had been evaluated by magnetic resonance imaging following surgery in order to assess the frequency of hind-brain herniation and hydrocephalus in these children. Magnetic resonance imaging had been performed in the postoperative evaluation of 34 cases of craniosynostosis who had undergone procedures intended to increase the intracranial volume. The position of the cerebellar tonsils and the presence or otherwise of hydrocephalus was recorded for all cases. The effectiveness of surgery in treating raised intracranial pressure (ICP) was evaluated by means of postoperative ICP monitoring and had been performed in 22 cases. Herniation of the hind-brain below the level of the foramen magnum was observed in 18 cases (53%). Hydrocephalus, requiring the insertion of a ventriculoperitoneal shunt, was present in 14 cases (41%) and had developed after the cranial vault procedure in 9. The mean sleeping ICP measured postoperatively was normal (<10 mm Hg) in 5, borderline (10-15) in 7, and raised (>15 mm Hg) in 10 cases. Cranial vault expansion in complex craniosynostosis may fail to address the underlying aetiology of intracranial hypertension. Furthermore, both hydrocephalus and hind-brain herniation may develop following such surgery. Neither the increase in intracranial volume afforded by cranial vault expansion nor the shunting of hydrocephalus precludes the persistence of abnormal ICP. These findings are discussed in the light of possible mechanisms, in addition to cephalocranial disproportion responsible for intracranial hypertension in complex craniosynostosis. The implications for the surgical management of complex craniosynostosis are reviewed.

Upper airway obstruction and raised intracranial pressure in children with craniosynostosis.

In children with craniosynostosis, raised intracranial pressure (ICP) and upper airway obstruction (UAO) are both common features. However, potential interactions between UAO and ICP during sleep are poorly understood. The aim of the present study was to compare the levels of ICP during sleep between a group of patients with syndromic craniosynostosis (with facial involvement and consequent UAO) and a group of control patients with isolated unicoronal synostosis (with no facial involvement and normal upper airways). Polygraphic cardiorespiratory sleep studies with continuous monitoring of ICP were performed during unsedated sleep in 13 children with syndromic craniosynostosis and 7 control patients with isolated unicoronal synostosis only. In the syndromic group, UAO was present in 11 out of 13 patients, with 8 out of 13 having frank obstructive sleep apnoea. In contrast, none of the control patients showed signs of UAO during sleep. There was no evidence of central apnoeas in any of the patients studied. Clinical histories taken from parents tended to underestimate the severity of the respiratory problems. Elevated ICP was seen in 10 of the 13 syndromic patients, with borderline raised ICP in the remaining three cases. In contrast, raised ICP was seen in only 3 of the 7 control patients, with borderline raised levels in 2 of the 7. For both patient groups, ICP was higher during active sleep compared to quiet sleep. Multiple regression analysis showed that ICP during active sleep was dependent upon disease severity (unicoronal/ multiple synostosis) and to the baseline ICP level during quiet sleep. Both raised ICP and airway obstruction were more apparent during active sleep. There was a significant correlation between severity of UAO and increased ICP in active sleep. We conclude that obstructive respiratory problems are frequent in the syndromic patients, and can be severe in a large proportion of cases; intracranial hypertension is also frequent in this group. Further studies are required to investigate the possibility of a causal relationship between upper airway obstruction and raised intracranial pressure.

Treatment of obstructive sleep apnoea using nasal CPAP in children with craniofacial dysostoses.

We studied a group of children (aged 2.2-15 years) with craniofacial dysostosis and obstructive sleep apnoea to assess the use of nasal continuous positive airway pressure (n-CPAP) as a palliative form of treatment. A variable period of time was allowed for acclimatisation to n-CPAP (1 day to 2 months), depending on the patient. Patients were then admitted for their first CPAP trial. Baseline breathing difficulty and the effectiveness of n-CPAP were assessed by respiratory sleep studies. Successful results were obtained with n-CPAP in five of the eight patients, with marked clinical and polygraphic improvements of the respiratory pattern immediately after n-CPAP was established. Of the remaining three cases, one child needed a prolonged period of acclimatisation to the n-CPAP system, one was withdrawn from the study, and one failed to respond to n-CPAP and was found to have complete blockage of the upper airways as a result of enlarged adenoids. Our results confirm that n-CPAP can be tolerated even by young patients and can be effective, and that it may be a useful alternative palliative treatment for obstructive sleep apnoea in children with craniofacial syndromes.

Subdural intracranial pressure monitoring in craniosynostosis: its role in surgical management.

In the management of craniosynostosis subdural intracranial pressure (ICP) monitoring has proved a useful and safe means of identifying those children with raised ICP who are at risk from its long-term sequelae and who would benefit from early surgical intervention. Overnight subdural ICP recordings have been obtained in 136 unoperated cases of craniosynostosis. Fifteen patients were studied both before and after cranial vault remodelling procedures. ICP was raised (> 15 mmHg) in 35%, borderline (10-15 mmHg) in 37% and normal (< 10 mmHg) in 27% of cases. Raised ICP was present in 28/53 of the syndromic craniofacial dysostosis cases and in 20/83 non-syndromic craniosynostosis cases investigated (P < 0.001). Raised mean ICP and periodic plateaux of sustained ICP during sleep were particularly associated with the syndromic cases. Of the 15 patients studied following cranial vault surgery, 9 showed a reduction in ICP, 3 were unchanged and 3 had higher ICP postoperatively. The results of ICP monitoring can contribute significantly to formulating a rational and staged surgical management plan incorporating the need to normalise ICP and correct the frequently severe functional and cosmetic consequences of these disorders.