PE15.1-4 | Fluids and Electrolytes — Practice Quiz

For a 10 kg child: 100 mL/kg/day × 10 kg = 1000 mL/day. The Holliday-Segar formula uses 100 mL/kg/day for the first 10 kg.

Holliday-Segar maintenance: 100/50/20 mL/kg/day for first 10 kg / next 10 kg / each additional kg. Equivalently 4/2/1 mL/kg/hr (the '4-2-1 rule').

Holliday-Segar: 100 mL/kg/day for the first 10 kg = 1000 mL for a 10 kg child. For 20 kg it would be 1500 mL (1000 + 50×10), and for >20 kg add 20 mL/kg beyond 20 kg.

Two or more of: restlessness, sunken eyes, drinks eagerly, slow skin pinch = 'some dehydration'. Plan B: ORS 75 mL/kg over 4 hours in a healthcare facility.

IMNCI dehydration: Plan A (no dehydration), Plan B (some — 75 mL/kg ORS over 4 h), Plan C (severe — IV Ringer's lactate 100 mL/kg, 30 mL/kg fast then 70 mL/kg over 2.5–3 h). The key differentiator between some and severe is the ability to drink (eager vs unable).

The presence of ≥2 signs (restless, sunken eyes, eager thirst, slow skin pinch) classifies this as 'some dehydration' per IMNCI — Plan B with 75 mL/kg ORS over 4 h, not 50 mL/kg and not IV Plan C.

Sodium correction must not exceed 10–12 mmol/L per 24 hours to prevent osmotic demyelination syndrome (ODS), even in symptomatic hyponatraemia.

Hyponatraemia correction: maximum 10–12 mmol/L per 24 h to prevent ODS. In symptomatic severe hyponatraemia (seizures), 3% saline 2–3 mL/kg IV may be given acutely to raise sodium by 4–6 mmol/L, then slow to the 10–12 mmol/L/24 h ceiling.

The maximum safe correction of hyponatraemia is 10–12 mmol/L in 24 h. Faster correction risks osmotic demyelination syndrome (ODS), a serious neurological complication. The rate limit applies regardless of consciousness.

Calcium gluconate IV is the first and most urgent step because it stabilises the cardiac membrane immediately, preventing fatal arrhythmia. It does not lower potassium but buys time for definitive therapies.

Hyperkalaemia management sequence: (1) Calcium gluconate IV — membrane stabilisation; (2) Insulin + dextrose IV — shift K+ in; (3) Sodium bicarbonate — shift K+ in (alkalosis); (4) Salbutamol nebulisation; (5) Kayexalate/furosemide — removal; (6) Dialysis if refractory. Max IV K+ infusion rate 0.5 mmol/kg/hr.

When hyperkalaemia causes ECG changes, cardiac membrane stabilisation with calcium gluconate is the immediate priority. Insulin+dextrose and bicarbonate shift potassium intracellularly but take longer. Kayexalate removes potassium over hours.

IMNCI Plan C: Ringer's lactate (preferred) 30 mL/kg over 30 minutes (15 min for infants), then 70 mL/kg over 2.5 hours (2.5 h for children >1 yr). Total = 100 mL/kg.

IMNCI Plan C: Ringer's lactate 100 mL/kg total — 30 mL/kg fast (30 min for children, 15 min for infants) then 70 mL/kg over 2.5 h. Reassess every hour; if not improving, repeat the fast phase.

Plan C uses Ringer's lactate (not normal saline or dextrose) in a two-phase regimen: 30 mL/kg fast, then 70 mL/kg over the remaining time. Normal saline is an acceptable alternative if RL is unavailable, but RL is preferred.

4-2-1 rule: 4 mL/kg/hr for the first 10 kg = 4 × 8 = 32 mL/hr for an 8 kg child.

The 4-2-1 hourly rule (equivalent to Holliday-Segar daily ÷ 24): 4 mL/kg/hr for first 10 kg, 2 mL/kg/hr for next 10 kg, 1 mL/kg/hr for each additional kg. For an 8 kg child: 4 × 8 = 32 mL/hr.

For a child ≤10 kg, the 4-2-1 hourly rule gives 4 mL/kg/hr. For 8 kg: 4 × 8 = 32 mL/hr. The 4-2-1 rule mirrors the Holliday-Segar daily formula divided by 24.

WHO reduced-osmolarity ORS (2003) has osmolarity 245 mOsm/L: NaCl 2.6 g/L (Na 75 mmol/L), KCl 1.5 g/L, glucose 13.5 g/L, trisodium citrate 2.9 g/L.

WHO reduced-osmolarity ORS (245 mOsm/L): lower sodium (75 vs 90 mmol/L) and glucose (75 vs 111 mmol/L) than the old standard ORS. Reduces stool output and duration; safe for all ages including infants. Osmolarity 245, NOT 311.

The original WHO ORS had osmolarity 311 mOsm/L. The reduced-osmolarity ORS (245 mOsm/L) was adopted in 2003 after studies showed improved efficacy and lower purging rates. NaCl content is 2.6 g/L, glucose 13.5 g/L.

Intraosseous (IO) access is the recommended emergency vascular access when peripheral IV cannot be established rapidly in a critically ill child. Fluids, medications, and blood products can all be administered via IO.

IO access: recommended when peripheral IV fails in a critically ill child. Standard site = proximal tibia (2 cm below tibial tuberosity, medial flat surface). All resuscitation fluids and drugs can be given IO. Initial flush with 10 mL normal saline before drug infusion.

IO access is the standard of care when peripheral venous access fails in a critically ill child. It provides rapid, reliable access at the proximal tibia. Cutdown and central lines are slower; deferring IV access is dangerous in severe dehydration.

At Na 128 with symptoms, hyponatraemia is acutely dangerous (seizures, cerebral oedema). K 2.8 requires correction but is less immediately life-threatening at this level. The rate limit for Na correction is ≤10–12 mmol/L/24 h to avoid ODS.

In hyponatraemia, the correction rate ceiling (≤10–12 mmol/L/24 h) is the critical safety constraint regardless of severity. Hypokalaemia: supplement cautiously in IV fluids (K max 0.5 mmol/kg/hr IV, never as IV bolus). Always correct associated dehydration to improve electrolyte balance.

Both abnormalities need attention. Hyponatraemia at 128 mmol/L in a symptomatic child poses an immediate seizure and cerebral oedema risk. Hypokalaemia at 2.8 mmol/L is significant but not immediately fatal at this level. The critical constraint is that Na correction must not exceed 10–12 mmol/L/24 h.

Flashback of blood into the cannula chamber indicates the needle tip is in the vein. Advancing the cannula off the needle, aspirating freely, and seeing no swelling on a test flush confirms intravascular placement.

IV cannula insertion steps: prepare site → tourniquet → clean skin → bevel-up 15–30° insertion → look for flashback → advance cannula over needle → withdraw needle → confirm with aspiration and saline flush → secure with transparent dressing. Blood flashback is the key confirmation sign.

Confirmation of IV placement requires: (1) blood flashback in the chamber, (2) free aspiration of blood, and (3) no swelling/pain on a small test flush of saline. None of the other options reliably confirm intravascular position.