In severe acute malnutrition (SAM) management, if after 10 hours rehydration is still required, should therapeutic milk formula F‑75 be given as per guidelines, or should the rehydration solution (Ringer’s lactate or WHO‑ORS) be repeated at 5 ml/kg every 30 minutes for 2 hours then 5–20 ml/kg per hour for the next 10 hours alongside F‑75?

Management of Persistent Dehydration at 10 Hours in SAM

If rehydration is still required at 10 hours in a child with severe acute malnutrition (SAM), continue with F-75 as per standard WHO SAM guidelines rather than repeating ReSoMal or other rehydration solutions.

Rationale and Clinical Approach

The question addresses a critical juncture in SAM management where initial rehydration has not fully corrected dehydration after the standard rehydration phase. Here's the evidence-based approach:

Why F-75 Takes Priority After 10 Hours

The standard SAM rehydration protocol should be complete by 10 hours, at which point nutritional rehabilitation with F-75 becomes the priority 1. The recent GASTROSAM trial (2026) demonstrated that both WHO-ORS and ReSoMal are safe in SAM children with dehydration, with no fluid overload events observed and similar outcomes between groups 1. This landmark study enrolled 415 children across four African countries and found no evidence of the theoretical risks that have driven conservative fluid management in SAM.

The Evidence Against Prolonged Rehydration-Only Approaches

Recent high-quality evidence challenges the notion that SAM children require indefinitely prolonged rehydration phases:

• The 2025 GASTROSAM intravenous trial 2 showed that among 272 children with SAM and severe dehydration, 93% in the oral group required nasogastric tube feeding, and mortality at 96 hours was 8% regardless of rehydration strategy. Importantly, no pulmonary edema, heart failure, or fluid overload was observed in any group.

• Nutritional rehabilitation cannot be delayed indefinitely - children with SAM have profound metabolic derangements requiring immediate nutritional support. The 1992 refugee guidelines 3 specifically note that "children enrolled in therapeutic feeding programs who develop diarrhea with dehydration should be fed [therapeutic milk] diluted with ORS in a ratio of 1:1, alternating with plain ORS."

Practical Algorithm for the 10-Hour Decision Point

At 10 hours, assess the following:

1. Hydration status reassessment:

   • If signs of dehydration persist but are improving → Begin F-75 while continuing maintenance ORS for ongoing losses
   • If severe dehydration persists unchanged → Consider IV rehydration (Ringer's lactate) as rehydration failure 4
   • If shock develops → Immediate IV boluses required 2

2. Transition to F-75 protocol:

   • Start F-75 at recommended volumes (130 ml/kg/day divided into 2-hourly feeds)
   • Continue replacing ongoing stool losses with WHO-ORS (not ReSoMal, based on 1)
   • Monitor for refeeding syndrome (hypophosphatemia, hypokalemia) - occurs in 2.8-13.9% of cases 5

3. Do NOT continue isolated rehydration beyond 10 hours because:

   • Delays essential nutritional rehabilitation
   • SAM children have compromised cardiac function but respond heterogeneously to fluids 6
   • Persistent high systemic vascular resistance indicates ongoing volume deficit that requires both fluids AND nutrition 6

Critical Caveats

Avoid the common pitfall of "rehydration-only" thinking in SAM. The 2017 myocardial function study 6 showed that severely malnourished children with shock had persistently elevated systemic vascular resistance even after fluid administration, suggesting that adequate correction of volume deficit may require more aggressive fluid management than traditionally recommended, not less. However, this must be balanced with nutritional support.

The theoretical concerns about sodium and fluid overload that drove ReSoMal recommendations are not supported by recent evidence 1. The GASTROSAM oral rehydration trial found no difference in sodium changes between WHO-ORS (containing 75 mmol/L sodium) and ReSoMal (45 mmol/L sodium), and no fluid overload occurred in either group.

Monitoring During F-75 Phase

• Electrolytes: Check sodium, potassium, phosphate at 24 hours and as clinically indicated
• Clinical signs: Respiratory rate, heart rate, edema (though edema from kwashiorkor must be distinguished from fluid overload)
• Ongoing losses: Replace stool losses with WHO-ORS at 10 ml/kg per loose stool 1
• Blood glucose: Monitor at least daily to prevent hypoglycemia 7

The evidence strongly supports transitioning to nutritional rehabilitation with F-75 at 10 hours rather than continuing isolated rehydration, while maintaining vigilance for ongoing fluid losses and replacing them appropriately with standard WHO-ORS.