4. Discussion
To the best of our knowledge, this is the first paper to examine NIV
adherence and efficacy in children with DS with a control population.
Our study demonstrates that satisfactory NIV adherence and efficacy
rates are achievable in children with DS compared with a non-DS cohort.
Overall, acceptable leakage levels and NIV efficacy were demonstrated
across different age groups and cohorts in our study. Children with DS
with known congenital cardiac disease who underwent cardiac surgery had
decreased NIV adherence when compared with children who had not
undergone cardiac surgery.
There are conflicting reports regarding NIV adherence in children with
DS throughout the literature. Previous studies have shown that poor
compliance and refusal are significantly more common in children with DS
due to behavioural and cognitive impairment 31. We
collected adherence data for twelve months in both DS and non-DS cohorts
and conversely to previous studies, we have shown that children with DS
showed increased usage relative to their non-DS counterparts, with the
DS cohort using NIV on more than 75% of nights, with >
4hrs use on more than 50% of nights. These data are in keeping with
that observed by Dudoignon et al, where good compliance was observed in
the majority of children with DS 20. Similarly, Trucco
et al showed satisfactory NIV adherence within a paediatric DS
population, with particular emphasis being placed on the initiation
period as a key factor in overall and enduring compliance23. The importance of early optimisation and
compliance is a sentiment echoed in the literature, Mansell et al have
highlighted the important role of early domiciliary ventilator downloads
to identify modifiable risk factors, such as adherence, as part of a
treatment protocol to optimise and personalise NIV treatment32.
Having established satisfactory compliance within our DS paediatric
cohort, we next looked at another key factor of therapeutic success,
effective NIV delivery and system leakage. To date, there have been no
studies investigating NIV leakage in a paediatric population;
furthermore the level of clinical ”tolerabilty” of leaks is not well
established in home NIV 33. Despite this, it is widely
known that leakage will significantly effect NIV performance34. In this study we identified that there was
significantly greater leak in the DS cohort relative to their non-DS
counterparts and this is particularly evident in those aged
>5yrs.
Upper airway surgery is often the first-line treatment of OSA in
children with DS 18. Although significant clinical
improvements are seen post-adenotonsillectomy, the prevalence of
residual OSA is reported to be between 47% and 70%22,35. In this study there was no difference in NIV
adherence in those with residual OSA relative to those with no history
of upper airway surgery. Furthermore, leak and time at excess leak was
more pronounced in those with DS that displayed residual OSA post ENT
surgery. This finding may have been due to craniofacial abnormalities
which are well described in children with DS. Reducing leak at the
patient-ventilator interface is important, not only to further promote
comfort and compliance but to enhance NIV efficiency. However, a degree
of mask leak is acceptable and the levels of leakage recorded across
both cohorts was low overall therefore was not likely to be clinical
significant.
Children with DS are more susceptible to developing the adverse sequelae
of OSA largely due to the myriad of co-morbidities 27,
and as such The American Academy of Pediatrics (AAP) recommend a
screening PSG for OSA be carried out before the age of 4 in all children
with DS, a sentiment echoed by the Royal College of Paediatrics and
Child Health 36-38. Up to 60% of children with DS
have a history of congenital and structural heart disease increasing
their predisposition to persistent, development and recurrence of
pulmonary hypertension if OSA goes untreated or undertreated14,15,26. Congenital heart disease has previously been
suggested to undermine the efficacy of upper airway surgical outcome22. Those with a history of congenital heart disease
and particularly those previously requiring cardiac surgery within the
DS population have an increased risk of the cardiac sequelae of
untreated OSA.
In this study, seventy-seven percent of this DS cohort has a past
medical history that includes cardiac disease. This higher than normal
percentage is likely due to the fact that our centre is the national
referral centre for congenital heart disease. We have shown that those
with a prior history of cardiac surgery have significantly poorer NIV
adherence compared with their non-surgical counterparts.
To date, this is the first study of its kind that has identified poor
NIV adherence within a DS cohort with prior cardiac surgery. Similarly,
previous studies have noted poor therapeutic compliance within an
adolescent and young adult cohort following heart or heart and lung
transplant 39. In this study by Wray et al,
unintentional and intentional non-adherence was assessed, factors
surrounding intentional non-compliance included perceived difficulty of
the therapeutic intervention, as well as, perceived benefit39. Treatment compliance in long-term paediatric
conditions is a complex issue, it must be looked at in the context of
the issue at hand, past medical and surgical history of the child as
well as the interaction of the family with healthcare and practitioners40. Parental non-compliance commonly arises from the
emotional stresses associated with the recommended treatment; NIV
initiation can be difficult and emotionally taxing on caregivers.
Parents make continued attempts to balance concerns about the treatment,
such as perceived effectiveness and the perceived long-term threat of
the condition 41. Impaired quality of life, as well as
psychosocial issues including, adolescence, racial/ethnic minority
status, and presence of mental health issues have been identified as
factors associated with non-compliance 42. Familial
predictors associated with non-adherence problems included single-parent
households, lower socioeconomic status, lower family cohesion, presence
of family conflict, and poor family communication42. It could be postulated that the perceived threat
of OSA is not as great as congenital heart disease and the therapeutic
intervention is viewed as labour intensive particularly in the context
of milder threat. These data highlight that increased surveillance and
follow-up may be required in children with DS on NIV who have undergone
prior cardiac surgery.
The major strength of this study is the inclusion of a control group.
Previous similar studies have reported only on DS cohorts and the
addition of a non-DS cohort adds significant weight to our findings. The
authors are aware of the limitations of this study. Firstly, this is a
single-centre retrospective study. The foremost scientific limitation of
this study was the restricted availability of follow-up PSG data once
NIV had been initiated, PSG data was not available to support and
compliment the at home recordings at the investigated time-points due to
limited resources. However the use of downloadable data from these NIV
machines is emerging across the literature demonstrating its importance
within clinical decision-making 32,43. Home NIV data
is becoming a key source of reliable information; it is not subject to
the recall bias of previous usage questionnaires and can inform the
clinician while helping to optimise patient care in a personalised
fashion 32,43.
In conclusion, this study confirms satisfactory NIV adherence in
children with DS compared with a non-DS population. Particular attention
should be given to children with DS and co-existing congenital heart
disease in respect to NIV adherence. As we enter an age of personalised
medicine, future studies should examine ways of improving NIV adherence
and efficacy further in children with personalised NIV masks that
incorporate 3D solutions to reduce system leak and discomfort44. Our study demonstrates that NIV delivery in
complex children in a tertiary paediatric setting can be successful and
that good adherence and efficacy levels can be achieved.