Transcript Low Osmolarity ORS : The Advantages (Against The Motion

LOW OSMOLARITY ORS:
The Advantages
(against the motion)
Dr Pravakar Mishra,MD
Asst. Prof. of Pediatrics
SVP PG Institute of Pediatrics,
Cuttack 753002
E-Mail:- [email protected]
BACKGROUND
• Under 5 Diarrhea- 1.5 Billion Episodes & 1.5 to 2.5 Million
deaths(5M. 20 yrs. back). JAMA. 2004;291:2628-2631.
• Widespread use of standard ORS in past 3 decades is with
promising results. JAMA. 2004;291:2628-2631.
• Most diarrhea deaths are caused by dehydration, which can
be treated by replacing fluid loss with ORS in over 90% of
cases. BMJ 2001;323:59-60
ORS development
None of the amino acid/ maltodextrin/
rice based ORS have been found
superior to standard ORS
Bhan MK, et al. Clinical trials of improved ORS formulation: a
review. WHO Bull.1994; 72: 945-55.
Table 1: Composition of standard and reduced
osmolarity ORS solutions
ORS
Standard
Reduced
Osmolarity
Contents
mEq/L
mEq/L
Glucose
111
75
Sodium
90
75
Chloride
80
65
Potassium
20
20
Citrate
10
10
Osmolarity
311
245
* 30 mmol/l of bicarbonate instead of 10 mmol/l of citrate
Randomized controlled trial…
A no. of RCTs have been conducted comparing the
standard (1975 WHO) and reduced-osmolarity (2002
WHO) solutions. In a trial of 300 adult patients with
cholera, those who received low osm. ORS had no
differences in stool output, duration of diarrhea, or need
for unscheduled intravenous therapy compared with
those treated with the standard WHO ORS.
cont…
RCT
Patients who received reduced-osmolarity ORS had an increased
incidence of hyponatremia (serum sodium level <130 mmol/L) (odds
ratio [OR], 2.1; 95% confidence interval [CI], 1.1-4.1). The mean
difference in serum sodium at 24 hours of treatment between the 2
groups was 1.2 mEq/L, and none of the patients with hyponatremia
in either group was symptomatic.
Christopher et al, JAMA, 2004,291:2628-2631
WHO and UNICEF joint meet 2001
Among adults with cholera, clinical outcomes
were not different among those treated with
reduced-osmolarity ORS compared with
standard ORS, although the risk of transient
asymptomatic hyponatremia was noted
Christopher et al, JAMA, 2004,291:2628-2631
WHO and UNICEF joint meet 2001
Further monitoring, including postmarketing
surveillance studies, were strongly encouraged
to better assess any risk of symptomatic
hyponatremia in cholera-endemic parts of the
world.
World Health Organization. Reduced Osmolarity Oral Rehydration Salts
(ORS) Formulation. New York, NY: UNICEF House; July 18, 2001 2001.
WHO/FCH/CAH/01.22.
Concerns
Pediatric and adult cholera patients typically lose
100 to 135 mEq of sodium per liter of diarrhea,
respectively. The reduced-osmolarity solution with
75 mEq/L of sodium would therefore induce a
negative sodium balance of ?25to ?60 mEq/L
ingested when matching intake to output.
Concerns Cont….
Adult diarrhea rates in severe cholera approach 1 L/h, so
losses of up to 300 mEq of sodium can accrue within 5
hours of such treatment, enough to sharply lower blood
sodium levels. Even with antibiotics, oral maintenance
usually lasts 24 to 44 hours in adult cholera patients,
enough to induce massive sodium deficits using the lowsodium solution. Moreover, to expand intravascular
volume rapidly, patients must drink more of a low-sodium
solution, which may lead to fatigue and treatment failure.
JAMA. 2004;291:2628-2631
Concerns Cont….
In malnourished patients with chronic hyponatremia and
multiple diarrhea episodes, very low-sodium oral
solutions (45 mEq/L) also aggravate hyponatremia (1 of
65 patients had seizure). Use of reduced-osmolarity
solution in these patients should be relatively
contraindicated, but the new recommendations do not
address this point.
JAMA. 2004;291:2628-2631.
Concerns Cont….
Another difficulty is that all studies of the new formulation
involved single-incident diarrhea episodes. Where
effective oral therapy programs exist, children may
receive therapy for multiple diarrhea episodes. Surveys
in several countries have shown more than 7 episodes of
varied etiologies per child annually. The risk of
aggravated hyponatremia might exist when such
patients, already sodium depleted, present for treatment
of incident episodes. This deserves study to determine
the safety of low-sodium solutions in such patients.
JAMA. 2004;291:2628-2631.
Concerns Cont….
Studies leading to the recommendation for the reduced-
osmolarity ORS for noncholera diarrhea therapy had
variable outcomes. Reduction in diarrhea rate, if real, is
minimal; diarrhea duration is unaffected. The need for
unscheduled intravenous fluids was not laboratory
confirmed, and in the largest study it was not paralleled
by reduced stool losses. For these reasons, and the risk
of induction of hyponatremia, it remains unclear whether
the new solution favorably alters the benefit-to-risk ratio
for pediatric and adult diarrhea patients without cholera.
Concerns Cont….
Additional, more rigorous studies are needed to
determine the optimal solution for such patients.
What is clear is that the reduced-osmolarity ORS
increases the risk for hyponatremia during
therapy in adults with cholera but offers them no
clinical advantages. Moreover, clinical findings in
small numbers of pediatric patients with cholera
were contradictory.
JAMA. 2004;291:2628-2631.
Experience with Standard ORS
The original WHO formulation with 90 mEq/L of sodium and 111
mmol/L of glucose proved a safe, effective formulation for all age
groups and cholera or noncholera diarrhea. However, failure to
communicate the information needed to ensure correct solution
preparation, concentration, and appropriate drinking volumes can
lead to electrolyte imbalance, whatever the formulation. Thus,
inaccuracies in home-mixing of solutions led to hypernatremia in
Egypt, a situation that was reversed with detailed instructions
broadcast via television and taught in rehydration clinics.
JAMA. 2004;291:2628-2631
Queries???
Should reduced osmolarity solution
replace the current WHO oral rehydration
solution as the new "standard" or should
there be two standard solutions, one for
regions where cholera is endemic and
another for everywhere else?
Thank You
Thank You