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Appendix A

Complications costing

It is thought that the majority of phlebitis resolves after the removal of the cannula. The costs
of phlebitis are therefore attributed to the re-siting of the cannula and all associated equipment
and staffing costs. Phlebitis costs are summarised in Table A.11. Potential antibiotic costs for the
treatment have been excluded from the model. Extravasation injuries as a result of phlebitis have
also been excluded from the model. The assumption made by the model is that the majority of
these injuries will resolve themselves with no treatment.
The model assumes that if a patient is diagnosed with paralytic ileus they would be transferred
to IVT and therefore the costs of paralytic ileus are encapsulated in the downstream cost of IVT
and not as a separate cost.

Table A.11 Phlebitis costs
Item Cost Notes
Cannula £0.78
Staff tasks: £8.42 It is assumed that re-siteing the cannula and associated tasks
• Ametop® application take approximately 15 minutes. These tasks are done by nurses
• cannulation and taking blood (band 5) and a specialty registrar.
samples
• fluid preparation/attaching

‘Worst case’ sensitivity analysis

In addition to the base case analysis, a ‘worst case’ analysis for ORT relative to IVT has been
considered. This was done in order to subject the findings of the base case model – that ORT
was more cost-effective – to the most vigorous scrutiny by biasing model assumptions, within
plausible limits, in favour of IVT. By carrying out a ‘worst case’ analysis, it is possible to determine
whether or not ORT remains the most cost-effective option even under assumptions that are
intended to represent the least favourable scenario for ORT.
Parameters changed for ORT

For this ‘worst case’ sensitivity analysis, the following changes were made:

Probabilities
For point estimates of proportions, the upper limit of the 95% confidence intervals were calculated
to obtain the highest probability of:
• failure to rehydrate following ORT
• paralytic ileus following ORT.

The implication of doing this is a higher percentage of patients failing ORT and therefore a higher
level of hospitalisation within ORT.

Staff
The GDG were asked to estimate the maximum time it could take staff to carry out ORT-related
tasks. These time values were used to calculate the maximum costs for labour for ORT (see
Table A.3).

Parameters changed for IVT
The ‘worst case’ favoured IVT and therefore the aim here was to cost up a much less resource-
intensive means of providing IVT. The following changes were made:

Probabilities
To try to make the best case for IVT, the probability of failing to hydrate following IVT and the
probability of complications (namely phlebitis) following IVT were changed to 0.

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