13.4 Weight-Based Dosing Aids & Drugs to Avoid Routinely

Pediatric Doses Are Weight-Based—So Weight Must Be Right Enough

Almost every critical PALS number scales with body size: epinephrine 0.01 mg/kg, amiodarone 5 mg/kg, adenosine 0.1/0.2 mg/kg, defibrillation 2 then 4 J/kg, cardioversion 0.5–1 then 2 J/kg, fluid boluses 10–20 mL/kg. A wrong weight multiplies into a wrong dose. In emergency care you often lack a scale. PALS therefore expects fluency with estimation tools and the judgment to use known weights when available.

Length-based tapes (Broselow and similar systems)

A length-based tape is laid alongside the supine child from crown to heel. Color zones or length marks correlate with an estimated weight and often list pre-calculated doses, equipment sizes (ETT, blade, suction), and defibrillation energies. These systems are designed for the stress of resuscitation, when mental arithmetic fails.

Length-based systems are estimates. They outperform wild guessing in most emergency settings and are strongly preferred over "looks like a 2-year-old, give adult epi."

Prefer actual weight when known

If the parent states a recent scale weight, the clinic chart lists today’s weight, or a bed scale reading is available and trusted, use the actual weight for calculations. Do not ignore a known accurate weight merely because the tape is open. Conversely, if the stated weight is obviously wrong or unknown, the tape (or other validated estimate) is safer than paralysis.

Other cognitive aids that save lives

• Code cards / PALS pocket references with dose tables
• Pre-calculated dose sheets printed at triage for the estimated weight
• Smart IV pumps and pharmacy-prepared infusions in hospital settings
• Independent double-checks for high-alert drugs (vasoactives, concentrated electrolytes)
• Closed-loop communication: "Epinephrine 0.01 mg/kg—0.14 mg—1.4 mL of 0.1 mg/mL IO" → "1.4 mL IO now"

Under megacode stress, humans default to error. Cognitive aids are not cheating; they are professional practice. Teams that refuse tools because "I memorized everything" still make decimal mistakes.

Drugs NOT Recommended Routinely in Arrest (2025 Emphasis)

Not every ampule on the code cart belongs in every pediatric arrest. Two classic examples—sodium bicarbonate and calcium—are frequent distractors. Both have narrow, indication-based roles. Neither is a default "metabolic fix" for every prolonged code.

Sodium bicarbonate — not routine

2025-aligned PALS teaching: Routine sodium bicarbonate is not recommended during cardiac arrest.

Why the old habit is wrong:

• Bicarbonate generates CO2 that the poorly perfused lung may not eliminate during CPR.
• It can worsen intracellular acidosis in some contexts.
• It does not replace ventilation, high-quality CPR, or cause-specific therapy.

Special circumstances where bicarbonate may be considered (exam-level list):

If the stem is ordinary asystole/PEA without those features, do not pick "give bicarb now" as the next best step over CPR, epinephrine, ventilation, and reversible-cause search.

Calcium — not routine

Routine calcium administration is not recommended in pediatric cardiac arrest.

Consider calcium when:

Calcium is a high-alert drug. Wrong-dose or wrong-salt errors occur. Use dosing aids and indication discipline.

Contrast table for rapid exam review

Hyperkalemia package (ties Chapters 11 and 13)

When hyperkalemia is the reversible cause, think membrane stabilization + shift + removal, not a single magic drug:

• Calcium to antagonize cardiac effects of high K+
• Sodium bicarbonate may be part of some pathways
• Insulin with glucose, β-agonists, and definitive removal (dialysis) per advanced care
• Stop potassium sources; treat the cause

The exam point is indication-driven use—not sprinkling calcium and bicarb into every PEA.

Putting Safety Systems Together on a Real Code

A practical dosing workflow

1. Estimate or obtain weight (scale > recent known weight > length-based tape > last-resort visual guess).
2. Open the cognitive aid for that weight (tape zone, card, app).
3. Select the drug and indication (arrest epi vs anaphylaxis IM vs antiarrhythmic).
4. Confirm concentration on the vial.
5. Calculate mg, then mL; have a second provider verify when possible.
6. Deliver via IV/IO, flush, document time.
7. Reassess rhythm, pulse, perfusion—not only the syringe empty light.

Megacode behaviors instructors reward

• Assigning a medication role who narrates doses aloud
• Using the tape early rather than after three dosing arguments
• Refusing "just give some bicarb" without an indication
• Catching a peer’s ten-fold epinephrine concentration error before injection
• Transitioning to infusions and charts post-ROSC instead of repeated random pushes

Clinical scenarios

Scenario A — Unknown weight: Unresponsive toddler-length child, VF arrest. Team pulls length-based tape, estimates 12 kg, defibrillates 2 J/kg (24 J), places IO, gives epinephrine 0.01 mg/kg (0.12 mg = 1.2 mL of 0.1 mg/mL). After refractory VF, considers amiodarone 5 mg/kg (60 mg). No routine bicarb.

Scenario B — Known weight: Parent reports 16.0 kg from this morning’s clinic visit. Use 16 kg even if the tape color suggests nearby. Dose epi 0.16 mg.

Scenario C — Hyperkalemia PEA: Child with renal failure, peaked T waves before arrest, wide complex PEA. Alongside CPR and epinephrine, treat hyperkalemia—including calcium for membrane stabilization and other shift/removal therapies per protocol; bicarbonate may be considered in this special circumstance. This is the opposite of "bicarb for every long code."

Scenario D — TCA overdose: Wide-complex toxicity from sodium-channel blockade—sodium bicarbonate is indication-based toxicologic care, not a generic PEA reflex.

Link forward

Access and pharmacology only work inside team dynamics (Chapter 14): clear roles, closed-loop communication, constructive intervention when someone reaches for the wrong concentration, and debrief that includes medication safety. The best dose math still fails if nobody flushes the IO or if CPR stops for three minutes of drug debate.

Bottom line for 13.4: Use length-based tapes when weight is unknown and actual weight when known; lean on cognitive aids to prevent error; and remember the 2025 rules—no routine sodium bicarbonate and no routine calcium in arrest without special indications such as hyperkalemia, sodium-channel blocker toxicity, hypocalcemia, or calcium-channel blocker overdose.