Discussion:
In 1981, Puchelle et al. showed that the saccharin test could be used as
a useful screening test in nasal mucociliary
clearance.[2] Various authors have also shown that
saccharin test is advantageous over other modalities of investigation.
Hence to assess the impact of tracheostomy on nasal mucociliary
clearance, a saccharin test was performed.
In 1995, Kleinschmidt et al. used the saccharin test and showed a
saccharin transit time (STT) of 624 seconds in healthy subjects while
the present study showed a mean STT of 447.4±63.2 seconds in control
group.[3]
Similar studies were done by Yergin et al., Stanley et al. showed a mean
STT of 432 seconds, 702±228 seconds, respectively, in healthy subjects.
Such variations in average mucociliary clearance time are attributed to
various factors such as habits, habitat, climate, facial configuration,
and comorbidities [4, 5, 6]. A study done by
Golhar et al. on 150 subjects from India revealed a mean nasal
mucociliary clearance time of 430 seconds (range: 320- 700 seconds)
which was consistent with the results of the present study. Golhar
further stressed that the saccharin test could be used as a valid
screening test, not only for the diagnosis of nasal mucociliary
impairment but also for the prognosis of various diseases of nasal and
lower respiratory tracts [7]. Karaoglu D et al.
conducted a study in which they studied the long-term effects of
laryngectomy on nasal functions and found that mean mucociliary
clearance time for laryngectomized patients was 1017.14 seconds whereas
in control group it was 662.5 seconds suggesting that physiological
alteration in the nose due to bypass of nasal airway, leads to reduced
ciliary clearance and impaired olfaction which can affect patients
quality of life and safety. [8]
In our study, mean nasal mucociliary clearance time (NMCT) was
934.97±75.9 seconds, these results were similar to study done by
El-Sharnouby et al. who conducted a study on 31 patients and found that
the mean saccharine test time recorded 2 months following tracheostomy
was 732.6± 323.4 seconds and at 6 months postoperatively was 1615±1042
seconds and was statistically significant.[9]However, study done by Yadav SP et al. on 30 tracheostomized patients
showed nasal mucociliary clearance time of 444±22.8 seconds when
saccharin test was done at 3 weeks following tracheostomy and NMCT
further reduced to 371.4±32.4 seconds in patients who were
tracheostomized for more than 3 weeks, suggesting that, following
tracheostomy, there is a significant decrease in nasal mucociliary
clearance time, particularly after 3 weeks postoperatively.[10]
A study was done by Tsikoudas A et al. in 2011 on 10 subjects in cases
and control arms respectively, where the author used SNOT-22, and
Rhinogram nasal symptoms score questionnaires and found that
tracheostomy group had a median Rhinogram score of 13.5 vs. 2 for the
control arm (p=0.02), and similarly SNOT-22 scores for tracheostomized
patients and controls were 39 and 29 respectively (p=0.205), thereby
observing that the tracheostomy group had more nasal symptoms due to
worsening of mucociliary clearance, which supports the hypothesis of
this present study and author concluded by stressing that this
impairment in nasal mucociliary clearance following tracheostomy should
be addressed in follow up as altered nasal function can predispose
patients to sinonasal diseases and a reduction in olfaction causing poor
identification of smell of food leading to a poor quality of life and
could become potentially dangerous in situations like gas
leak.[11]
Smaller sample size was one of the limitations of this study hence
further studies with larger sample size and follow-up can be done to
better understand these changes in nasal mucocilia and whether these
changes are reversible following decannulation, additionally we can also
determine whether techniques like polite yawning etc. can be used to
improve nasal mucociliary physiology and olfaction in these
tracheotomised patients.