Broselow Tape and Weight Estimation in Pediatric Emergencies

Hardly any scenario in emergency medicine generates more stress than managing a critically ill child. A key reason: nearly every therapeutic intervention – from medication dosing to endotracheal tube size to defibrillation energy – depends on body weight. While standard dosing can be used for adults, misjudging a child's weight quickly leads to clinically relevant over- or underdosing. The Broselow Tape is one of the most well-established tools for quickly and reliably estimating weight in such situations. But it's not the only one. This article covers the correct use of the Broselow Tape, compares alternative estimation formulas, and provides you with concrete dosing tables for the most common pediatric emergency medications.

Why Weight Estimation Is Critical in Pediatric Emergencies

Children are not small adults – this principle runs through all of pediatrics and applies to emergency medicine in particular. The therapeutic window of many emergency medications is significantly narrower in children than in adults. A ten percent deviation from actual weight can already have clinically relevant consequences in an infant.

The challenges in detail:

• High variability: A one-year-old child weighs an average of 10 kg but can physiologically range between 7 and 13 kg.
• Stressful situation: Parents are often too distressed to respond or don't know the current weight. A scale is rarely available in the prehospital setting.
• Cognitive overload: Mental arithmetic under time pressure and emotional stress is a common source of error. Studies show that dosing errors in children occur up to ten times more frequently than in adults.
• Equipment selection: In addition to medications, endotracheal tube size, laryngoscope blade, IV catheter size, and defibrillation energy must all be adapted to the child.

This is precisely where length-based weight estimation systems come in: they turn a complex estimation task into a simple, reproducible measurement.

The Broselow Tape: Design and Functional Principle

The Broselow Tape (also known as the Broselow-Luten Tape) is a color-coded measuring tape that measures a child's body length and derives an estimated body weight along with corresponding dosages and equipment sizes. It was developed by James Broselow and Robert Luten and is an integral part of many PALS algorithms.

Basic Principle

In children, body length correlates better with weight than estimated age. The tape uses this correlation and divides children into color zones, each corresponding to a weight range.

Color Zones and Weight Ranges

Color Zone	Weight Range (kg)	Approximate Age
Grey	3–5	Newborn
Pink	6–7	Infant (approx. 3–6 months)
Red	8–9	Infant (approx. 6–9 months)
Purple	10–11	approx. 9–12 months
Yellow	12–14	approx. 1–2 years
White	15–18	approx. 2–4 years
Blue	19–23	approx. 4–6 years
Orange	24–29	approx. 6–8 years
Green	30–36	approx. 8–10 years

Note: Exact values may vary slightly depending on the tape version.

Correct Application – Step by Step

Correct measurement technique is crucial for accuracy:

1. Position the child supine on a firm surface.
2. Place the red end of the tape (marked "Measure from this end") at the crown of the head – not at the forehead.
3. Unroll the tape along the child's length down to the heel. The child should be lying stretched out with feet in a neutral position.
4. Read the color zone at the heel. The heel, not the tips of the toes, determines the zone.
5. Read the weight, medication dosages, and equipment sizes directly from the corresponding color zone.

Common Application Errors

• Measuring clothed children with shoes on: Leads to systematic overestimation of length and therefore weight.
• Placing the tape at the chin instead of the crown: Shortens the measured length.
• Measuring a child in a flexed position: Especially in infants who tend to draw up their legs, the length is underestimated.
• Using the tape for children over 36 kg: The Broselow Tape is validated for children up to approximately 36 kg (approximately 150 cm body length). For larger children, other methods should be used.

Limitations of the Broselow Tape

The Broselow Tape was developed and validated in a predominantly North American study population. Some important limitations:

• Obese children: With increasing prevalence of childhood obesity, the Broselow Tape systematically underestimates actual weight in overweight children. However, it is debated whether obese children should be dosed according to actual or ideal body weight – for most emergency medications, dosing based on ideal body weight (i.e., the Broselow weight) is recommended.
• Malnourished children: In populations with high prevalence of malnutrition, the tape overestimates weight.
• Ethnic variability: Body proportions vary between populations. Accuracy may be reduced in non-North American cohorts.

Despite these limitations, available evidence shows that the Broselow Tape estimates weight within ±10% of actual weight in over 50–65% of cases, making it superior to or at least equivalent to other estimation methods (particularly pure age-based estimation).

Alternative Methods of Weight Estimation

Age-Based Formulas

When no Broselow Tape is available, age-based formulas can serve as a fallback strategy. The most common:

APLS Formula (for children 1–10 years):

• Weight (kg) = (Age in years + 4) × 2

Modified Luscombe-Owens Formula:

• Weight (kg) = (Age in years × 3) + 7

For infants (0–12 months):

• Weight (kg) = (Age in months + 9) / 2
• Or simplified: Birth weight doubles by 5 months, triples by 12 months.

Evaluation of the formulas:

Formula	Advantage	Disadvantage
APLS	Simple, widely used	Tends to underestimate weight in older children
Luscombe-Owens	More accurate for older children	Less widely known
Age in months	Useful for infants	Requires known age

Fundamental problem with all age-based formulas: They require the age to be known. In emergency situations with unresponsive caregivers or unaccompanied children, the age is often unobtainable. Furthermore, age correlates less well with weight than body length.

Pediatric Emergency Rulers (PAWPER Tape, Pediatric Emergency Ruler)

Newer systems such as the PAWPER-XL Tape (Pediatric Advanced Weight Prediction in the Emergency Room) attempt to overcome the limitations of the Broselow Tape by incorporating body habitus (slim, normal, obese) in addition to body length. Accuracy in studies tends to be higher than with the classic Broselow Tape, but application is somewhat more complex.

Parental Inquiry

When parents are present and able to communicate, parental weight estimates are surprisingly accurate – in many studies even more accurate than age-based formulas. The question "How much does your child weigh?" should therefore always be asked when the situation allows. Caution is warranted with very agitated parents or when the last weight measurement was a long time ago.

Decision Algorithm for Weight Estimation

For clinical practice, the following prioritization is recommended:

1. Actual weight (scale, if available and time permits)
2. Reliable parental report of the last measured weight
3. Length-based estimation (Broselow Tape, PAWPER Tape)
4. Age-based formula (only as a fallback strategy)
5. Pure clinical estimation (least accurate method – only as a last resort)

Dosing Aids for Pediatric Emergency Medications

Correct weight estimation is only the first step. The weight must then be converted into the correct dose. Pre-made tables, dosing cards, or smartphone apps are indispensable here.

Common Emergency Medications – Dosing Overview

Resuscitation / PALS Algorithm:

Medication	Dosage	Maximum Dose	Notes
Epinephrine IV/IO	0.01 mg/kg (= 0.1 ml/kg of 1:10,000 solution)	1 mg	Repeat every 3–5 min
Epinephrine endotracheal	0.1 mg/kg (= 0.1 ml/kg of 1:1,000 solution)	2.5 mg	Only if IV/IO not possible
Amiodarone IV/IO	5 mg/kg	300 mg (1st dose)	For shock-refractory VF/pVT
Lidocaine IV/IO	1 mg/kg	100 mg	Alternative to amiodarone
Atropine IV/IO	0.02 mg/kg	0.5 mg	Minimum dose 0.1 mg
Defibrillation	2 J/kg (1st shock), 4 J/kg (subsequent)	10 J/kg or adult dose	Biphasic
Cardioversion (synchronized)	0.5–1 J/kg (initial), 2 J/kg (escalated)	–	For SVT, VT with pulse

Airway and Anaphylaxis:

Medication	Dosage	Maximum Dose	Notes
Epinephrine IM (anaphylaxis)	0.01 mg/kg of 1:1,000 solution	0.5 mg	Vastus lateralis, repeat every 5–15 min
Salbutamol nebulized	2.5 mg (<20 kg) / 5 mg (>20 kg)	–	For bronchospasm
Prednisolone PO/IV	1–2 mg/kg	60 mg	For croup, asthma, anaphylaxis
Dexamethasone PO/IV	0.15–0.6 mg/kg	16 mg	Preferred for croup
Ipratropium bromide nebulized	250 µg (<20 kg) / 500 µg (>20 kg)	–	In addition to salbutamol for severe asthma

Seizure / Status Epilepticus:

Medication	Dosage	Maximum Dose	Notes
Midazolam buccal/intranasal	0.2 mg/kg	10 mg	First-line therapy prehospital
Midazolam IV/IO	0.1 mg/kg	5 mg	If access available
Diazepam rectal	0.5 mg/kg	20 mg	Alternative if midazolam unavailable
Levetiracetam IV	40–60 mg/kg	3000 mg	Over 15 min, second-line therapy
Phenobarbital IV	20 mg/kg	1000 mg	Over 20 min, if first-line therapy fails

Other Important Emergency Medications:

Medication	Dosage	Notes
Glucose (10%) IV	2–5 ml/kg	For hypoglycemia; in neonates: 2 ml/kg D10%
Normal saline (0.9%) bolus	20 ml/kg	Over 5–20 min; for sepsis/shock, repeat after reassessment
Adenosine IV	0.1 mg/kg (1st dose), 0.2 mg/kg (2nd dose)	Maximum dose 6 mg / 12 mg; rapid bolus with flush
Naloxone IV/IM/IN	0.1 mg/kg	Maximum dose 2 mg; for opioid intoxication

Practical Tip: Dilutions and Error Prevention

A common and potentially fatal error is the confusion of epinephrine concentrations:

• 1:1,000 (1 mg/ml): For IM administration in anaphylaxis and endotracheal application
• 1:10,000 (0.1 mg/ml): For IV/IO administration during resuscitation

The AHA guidelines consistently recommend using mg/kg notation rather than dilution ratios to minimize confusion. Nevertheless, clear team communication about which concentration is being drawn up is essential.

Additional strategies for error prevention:

• Whenever possible, dose medications using pre-made dosing tables or cards rather than mental arithmetic
• Closed-loop communication: Announce the dose, have the person preparing it repeat it back, confirm again before administration
• Watch for "10-fold errors" – the most common type of error in pediatric dosing (decimal point errors)
• When possible, use standardized syringes with pre-prepared dilutions

Equipment Sizes by Weight

In addition to medication dosages, the Broselow Tape also provides recommendations for selecting the correct equipment size. The most important reference values:

Endotracheal tube size (uncuffed):

• Internal diameter (mm) = (Age in years / 4) + 4

Endotracheal tube size (cuffed):

• Internal diameter (mm) = (Age in years / 4) + 3.5

Laryngoscope blade:

• Neonates: Miller 0–1 (straight)
• Infants: Miller 1 (straight) or Macintosh 1
• Toddlers: Macintosh 2
• School-age children: Macintosh 2–3

Laryngeal mask airway (supraglottic airway):

Weight (kg)	LMA Size
< 5	1
5–10	1.5
10–20	2
20–30	2.5
30–50	3

IV Access:

• Neonates/infants: 24–22 G
• Toddlers: 22–20 G
• School-age children: 20–18 G
• In emergencies: Intraosseous access (IO) as an equivalent alternative for difficult venous access – insertion site: proximal tibia (1 cm medial and distal to the tibial tuberosity)

Integration into Teamwork

The best dosing aid is of little use if it is not systematically employed during an emergency. Proven strategies for team-based use:

• Keep the Broselow Tape as standard equipment in the pediatric emergency bag and ensure its location is known to the team
• Color-coded emergency kits: Some EMS systems and emergency departments organize pediatric equipment in drawers or bags corresponding to the Broselow color zones – so every team member immediately reaches for the right material
• Announce the weight first: As soon as the tape is applied, the estimated weight is communicated aloud to the entire team and recorded on the chart
• Dedicated "medications" role: One team member is exclusively responsible for dose calculation and preparation
• Regular training of pediatric emergency scenarios in simulation format to automate workflows and identify error sources

Practical Training

The correct use of the Broselow Tape, safe dosing of pediatric emergency medications, and structured management of critically ill children are most effectively trained in realistic simulation scenarios. In the PALS course (Pediatric Advanced Life Support) by Simulation Tirol, you work through pediatric emergency algorithms systematically in small groups – from weight estimation to medication dosing to team communication. The AHA-certified course format combines theory with hands-on exercises, so you can rely on automated, safe workflows when it matters most.