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Assessment
Central to the scientific
investigation into the efficacy of approaches for the control
of these side effects is the evaluation and quantification of
nausea and emesis. Different methods are needed for the assessment
of vomiting and of nausea. Vomiting can be measured objectively,
within certain limitations, based on the type of measurement used.
Nausea is completely subjective and exists only as the
patient defines it --- no external frames of reference or alternatives
to self report have proven adequate.
- Direct observation
-- Vomiting can be assessed by simply observing the patient
and counting the number of vomiting episodes. This was actually
done in early antiemetic studies where patients were often hospitalized
for cancer chemotherapy treatments. It is no longer done as
patient self reports of emesis are typically the new standard.
People do not usually have any confusion over whether or not
they have thrown up.
- Self Report--Nausea
is a subjective feeling that is individual to each patient and
only the patient can report the presence or grade the severity
of the nausea. There are two primary methods for assessing nausea:
- Some
type of interval
or Likert scale, which relies on descriptive words; and
- Some variation
of a visual
analogue scale, which typically uses a 10 cm line marked
in increments to illustrate the points between two extremes.
Delayed
emesis and delayed nausea
are important factors in the assessment of antiemetic effectiveness
that are often overlooked. Comparative antiemetic trials should
be specifically designed to evaluate these symptoms. They should
be accounted for by describing both the day-by-day responses in
order to evaluate the pattern of the phenomenon, and the summary
experience across the trial.
A patient
diary best accomplishes this. We have not had problems with
patients completing recordings of their nausea and emesis experience
in time periods corresponding to : "morning, afternoon, evening,
and night" over a five day period. Patients complain about
more frequent recordings or longer time periods of diary recordings;
and that reduces compliance. Both approaches are useful in comparing
and evaluating the potential relationship(s) between delayed emesis
and potential prognostic factors.
There is no place in
assessment for measures of "retches" since they cannot
be reliably differentiated from dry heaves or gags and, besides,
none of the three have anything to do with either nausea or emesis.
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