The case for using 200 mL sachets of ORS, rather than the usual 1 L sachets, for the home treatment of diarrhoea can be summarised as follows:
Two 1 L sachets
Four 200 mL sachets
|• Difficult to comply (incorrect dilution)||• Easier to comply (correct dilution)|
|• High contamination risk||• Lower contamination risk|
|• High wastage (>50%)||• No wastage|
|• Sufficient for 2 days of treatment||• >3 days of treatment|
|• Increased perception of ORS effectiveness|
|• User-centric design|
These issues are outlined in more detail below.
Vessels to measure 1 litre of water are very uncommon in homes especially in low income households. Many people will not know what a litre is. This means that many carers mix the ORS incorrectly in one of two ways:
- They use a whole sachet but do not have a 1 litre vessel to measure the volume of water correctly.
- They use part of sachet and mix it with a smaller volume of unmeasured water and judge dilution rate based on taste, colour (for coloured preparations of ORS) and/or what they perceive to be the correct dilution.
In the ColaLife Trial, of the carers who used a whole ORS sachet (and most did), only 60% used the correct amount of water. In other words 40% mixed the ORS incorrectly and produced solutions of unknown and potentially dangerous or ineffective concentrations.
In the same trial 93% of carers mixed the ORS correctly when given 200 mL sachets which were supplied in packaging that could be used to measure the water (see Kit Yamoyo).
The recommendation is that unconsumed ORS solution should be discarded after 24 hours because of the increasing likelihood of contamination. Supplying ORS in 1 litre sachets means that the carer will mix ORS once a day and the mixed ORS will be open to contamination for a full 24 hours. Mixing ORS in batches of 200 mL (a glass full) greatly reduces the potential of contamination and eliminates wastage.
Unconsumed ORS solution should be discarded after 24 hours. In a 24 hour period an under 5 child will consume 400ml of ORS solution on average. This means that a carer will generally throw away more ORS solution (600 mL) that the child drinks (400 mL).
In Western eyes this appears as a waste of ORS. In a carer’s eyes, who has had to bring the water to the house and fetch wood to boil it to make it safe, it is perceived as a waste of safe water.
With 200 mL sachets, there is no wastage as the child will drink this quantity well within the 24 hour period.
Duration of treatment
Providing carers with two 1 litre sachets of ORS, which is standard practice, provides sufficient ORS to administer ORS for 2 days. In the ColaLife Trial we found that, in practice, carers eke this out to 2.75 days. But this practice comes with the increased risk of contamination. However, when carers were given 200 mL sachets, there is no wastage and they treated their child for longer (3.55 days). Giving less total ORS, but in more appropriate sachet sizes, increases the number of days carers treat their children.
Amount of ORS dispensed when using 1 L vs 200 mL sachets
The graph below from the ColaLife Trial shows that 80% of mothers used four 200ml sachets or less. Then there is a blip in the data where 10% of mothers used all 8 of the sachets provided in the trial kit. This use of 8 sachets does not follow the pattern of administering ORS which otherwise follows the course of the bout of diarrhoea. It is likely that the carers who used 8 sachets did not do so because they needed to, but because 8 sachets were provided. If you accept this, then 90% of women used four sachets or less. This is equivalent to a total of 800 mL of ORS solution or 16.5 g of ORS. This is less than half (40%) of the amount provided when ORS is dispensed as two 1 litre sachets (41.4 g of ORS).
Perception of effectiveness
In the ColaLife Trial we increased the perception of ORS as an effective treatment for diarrhoea by 14 percentage points over 12 months. At the baseline, 78% of carers thought ORS was an effective treatment for diarrhoea. After 12 months this had risen to 92%. This increase cannot all be attributed to the smaller sachet size, as the kit supplied had other user-centric design features, but this is likely to have had some influence.
The carer experience
As well as the considerations above, 200 mL sachets are a ‘user-centric’ design. Consider the situation of the carer (usually the mother) with a sick child and imagine how it feels when you are given two 1 litre sachets of ORS to treat your child. Also, bear in mind that the carer may have to start treatment at night, in the dark:
- You will have difficulty finding a vessel that measures one litre.
- You are likely to have difficulty sourcing a whole litre of safe water. In most circumstances the water will have been carried to the home and will have needed to be treated (boiled usually) to make it safe.
- After 24 hours you will need to throw away what’s not been consumed (600 mL on average) and start again with the second sachet.
Aside from these practical challenges, how would you feel as a mother? Would you feel you were doing the right thing? Would you feel you were doing the best thing for your child?
Why are we giving 1 L sachets of ORS for the home treatment of diarrhoea?
The reason for this practice is probably historic. When ORS was first manufactured (30 years ago), it was produced for use in institutions (clinics, hospitals etc). In this setting you are likely to have multiple diarrhoea cases and it is useful to mix up ORS a litre at a time. In addition, health staff are more likely to know what a litre is and so will mix it correctly and contamination is less likely to be a problem as the mixed ORS will be given over a short period of time to multiple patients.
In the early days of manufactured ORS use, the recommendation was to use sachets of ORS in institutions and homemade ORS for the home treatment of diarrhoea. However, the results of using homemade ORS are generally poor and with the advent of ‘Low Osmolarity ORS’, the recommendation changed in 2002 and Low Osmolarity ORS became the recommended treatment in all settings – in the home as well as institutions. Homemade ORS remains the recommendation only when Low Osmolarity ORS is unavailable.
The problem is that when the recommendation to use Low Osmolarity ORS for home treatment was made, nobody seems to have considered the issue of the way the ORS is packaged for the home treatment of diarrhoea and we continue to give the same sachets for home treatment that are used in institutions with all the above challenges.
 Touchette PE, Elder J, Nagiel M. (1990) How much oral rehydration solution is actually administered during home-based therapy? J Trop Med Hyg. 1990 Feb;93(1):28-34.
A note on the data in this post
The data contained in this blog post are unpublished and based on preliminary analysis of data from the ColaLife Operational Trial in Zambia (COTZ). Final calculations may vary and will be published in peer reviewed literature in due course. In the interim, the following citation may be used: Ramchandani, R. et al. (forthcoming). ColaLife Operational Trial Zambia (COTZ) Evaluation. Johns Hopkins Bloomberg School of Public Health, Baltimore. Related correspondence should be sent to Rohit Ramchandani (firstname.lastname@example.org) and copied to Simon Berry (email@example.com).