122 / 242
122
Chapter 9
care they receive.
18
This subjective affective component makes measurement of satisfaction
challenging because frequently not all relevant items are addressed, and ‘minimal clinically
important difference’– meaning the smallest meaningful change that a patient can detect
with confidence – is difficult to define precisely.
19
This means that statistically significant
data are not always clinically relevant, and that satisfaction is difficult to compare in different
settings and at different time points.
Consequently, one limitationof our study is that the instrument of assessment of patients’ and
endoscopists’ satisfactionmay be criticised. However, only a few validated questionnaires on
patient satisfaction during sedation are available and we chose the validated questionnaire
developed by Vargo et al.
10
for sedation during colonoscopy and upper gastrointestinal
endoscopy in the United States. Patients’ expectations of sedation experience and therefore
their satisfaction are surely subject to national peculiarities, and it might be a limitation
to transfer a translated version of this questionnaire to Dutch patients without previous
validation. Our sample size calculation was based on patient’s satisfaction estimated by one
specific questionnaire. Probably, it would have been more appropriate – considering that
the safety profile of dexmedetomidine is more relevant within a clinical setting – to power
the study for acute respiratory or haemodynamic adverse events. However, much larger
scaled studies would have been necessary to address this outcome. We considered all these
events as possible problems and drawbacks, but their clinical impact cannot definitively be
determined from the present results. Our dosage of dexmedetomidine was in line with
other studies,
20,21
and is in line with the recommended maximum dosage approved by the
Food and Drug Administration for procedural sedation, but there was no preliminary study
on a potential dose-response for dexmedetomidine. With the exception of one patient, it
was not possible with this dosage to reach a sedation level (OAAS/S 2 to 4) sufficient to
facilitate the procedure tolerably for patients and endoscopists. The OAA/S scale may not
be the ideal tool to judge sedation depth using dexmedetomidine, as this score was not
validated for sedation with dexmedetomidine.
22
Our study was designed as a single centre trial using our standard sedation regimen with
propofol and alfentanil as comparator for dexmedetomidine and alfentanil. Although
propofol has gained the role as ‘gold standard’ for sedation, the use of the AMC standardised
TCI sedation protocol could limit generalisation of our data.
CONCLUSION
Dexmedetomidine sedation – even combined with analgesics – was less satisfactory
than sedation with propofol and caused haemodynamic depression after endoscopic
oesophageal procedures.