DISCUSSION
Despite having many mucolytic agents to aid ACT in bronchiectasis,
research data to guide their use in children are very
limited.24 Hypertonic saline as an airway hydrating
treatment has not been sufficiently studied even in adults withnon-CF
bronchiectasis and to the best of our knowledge we have not found any
randomized trials in children with non-CF bronchiectasis that could
warrant use of HS in routine management.
Results of this study on use of 3% HS as a mucolytic agent prior to
chest physiotherapy in children with non-CF bronchiectasis were
promising.
Luis Maize Carro et al (2019) in their review on HS in non-CF
bronchiectasis did not find any trials done on paediatric age group and
the 3 randomized clinical trials reviewed by them were of patients more
than 18 years of age.25 Number of patients in those
studies that were done by Kellett et al (2005)21,
Kellett et al (2011)22 and Nicolson et al
(2012)26 had been 24, 28 and 40 respectively with a
dropout rate ranging between10-15%.
Although there was a slightly higher dropout rate (17%) in our study,
52 completed, and some of the reasons were logistic, than individual
reasons such as poor compliance.
There were no dropouts due to the adverse effects of 3% saline
nebulization in this study similar to two randomized crossover trials on
the use of HS (7%) in non-CF bronchiectasis in
adults.21,22 In contrary a trial done in Australia
with 43 children with CF related bronchiectasis had 50% of its dropouts
due to irritating cough and worsening of haemoptysis following HS
nebulisations.27
Mean age of the study group (9.51± 2.67) was similar to a study done in
India on non-CF bronchiectetic patients (9.6 years).28
The baseline mean FEV1 and FVC of both arms of the trial were between
60-70% reflecting moderate impairments, which could partly be due to
the relatively late diagnosis of bronchiectasis (mean ages of diagnosis
are 5.6 years in HS group and 6.3 years in the conventional group).Yet
this trial demonstrated a significantly higher mean improvement in
predicted FEV1 in the HS arm during both phases of the study.
A crossover trial conducted in United Kingdom which studied the
effectiveness of 7% hypertonic saline nebulisations in improving lung
functions of patients with bronchiectasis showed similar results to this
study. The two groups of patients received a random order active HS or
Isotonic saline (IS) daily for 3 months and a 4 week wash-out phase was
included between phases. Mean predicted FEV1 in the trial had been
66.42±6.1, which was very close to our study results. The improvements
in FEV1 and FVC were statistically significant in favour of HS
(FEV1=15.1±1.8, p < 0.01; FVC=11.2 ± 0.7, p <
0.01).22The same study showed a significant
improvement in frequency of exacerbations in favour of HS (2.14
exacerbations /year in HS group vs. 4.85/year in IS group) keeping with
the frequency of exacerbations reported in our study during the first
phase (2.5 exacerbations/yearn HS vs. 7.8 exacerbations /year in
controls) of the trial.
In contrary, another study which had a higher baseline mean predicted
FEV1( 84.8±20.5 in HS group and 80.4±21.1 in control group) did not
demonstrate any significant improvement between the two arms after
intervention.26 Therefore authors concluded that a
significant improvements difficult to observe when there is a higher
baseline dynamic lung function test.
Mean improvement in FEV1 and FVC between the two groups were less during
phase II compared to phase I and the number of exacerbations between the
two groups was also not significantly different. This may be due to the
better compliance with the ACT protocol in both groups towards the end
of the study period in the majority. Also it could be that after a
certain improvement, the base line lung functions have improved and
thereafter the rate of improvement would be less.
Murray et al in their randomized cross over trial of chest physiotherapy
in non-CF bronchiectasis describes a significant improvement in all
domains of lung functions in patients who underwent regular chest
physiotherapy compared to the group who received no physiotherapy.29
The results of 3 trials evaluated in a systematic review done in 2017 on
various mucoactive agents for chronic, non-CF lung disease have favoured
HS over other agents and techniques after 3 months of administration.
However, the effects had not been significant at 12
months.30All children of the current study were
continued on ACT with HS after completion of the study and the
consistency of the effectiveness could be measured in future.
Most of the studies available in the published literature, which used
HS, were to compare the effectiveness of Hypertonic saline as a
mucocilliary agent with other mucoactive agents. Objective of our study
was to compare the effectiveness of HS incorporated ACT to conventional
ACT. Therefore even 0.9% saline was not used in the control arm which
could improve mucocilliary activity and show clinical improvement. Being
an open label study and an unblinded evaluation with short term follow
up are some of the limitations than could be seen in this study.