There are many assessment tools
for measuring the severity of nausea and vomiting.
A major issue in interpreting
and comparing
studies on the management of NVP has been the use of numerous
different methods to qualify and quantify nausea, vomiting
and related symptoms. Different researchers have arbitrarily
defined
NVP as "mild", "moderate" or "severe" without
clear quantitative definitions or biological logic.
Often
the assessments have been retrospective. In some cases
end points were measured dichotomously as success/failure
or as percentage preferring one drug over the other (in
crossover studies). While these approaches may be reasonable
in randomised
control trials (RCTs), assuming that all arms of the studies
are evaluated similarly, the clinical interpretation of
arbitrary endpoints and comparison between studies becomes
difficult,
if
not impossible.
We feel that future studies should use a
standard, validated tool that will allow comparison among
studies.
The Rhodes
Index appears to be an optimal tool for this purpose. It
separately scores, as categorical variables,
the number
of vomiting episodes per day, the size of the vomiting,
the degree
and length of nausea and retching, as well as the distress
associated with the condition (Table 1). The inventory
can be done once
or twice a day and, in addition to an overall score,
one can report separately on the frequency and changes in nausea,
vomiting,
retching and stress.
TABLE 1: RHODES INDEX OF NAUSEA, VOMITING AND RETCHING
