# Rounding rules

Published

I've been doing some pediatric safe dosage range questions and in my book the weight is first converted to kg and rounded to the nearest 10th then you proceed with the math problem. This is the way we were taught in school. While reading some other books it said to round pediatric weight to nearest hundredth. And other books the weight is not rounded at all. So is it correct to round pediatric weight to nearest 10kg then proceed with math problem?

1 Article; 7,349 Posts

Specializes in Pedi. Has 16 years experience.

To the nearest 10 kg? Most definitely not. The nearest 10th? In an older child, maybe. In an infant or preemie, probably not.

When I worked in the hospital, our infant scales went to the 3rd decimal point, the standard scale for older kids went to 1. Infant weights were definitely documented and used for calculation out to the 3rd decimal point. Preemies sometimes weigh less than 1 kg, rounding could lead to a very significant dose change. For example, you have a preemie who weights 851 g. If you use this to calculate a drug that's dosed at 100 mg/kg, your baby's dose is 85 mg. If you round to 900 g/0.9 kg, the dose of that medication is now 90 mg. For a baby that small, that could be significant.

1 Article; 2,282 Posts

Specializes in Pediatric Critical Care.

At most, I will round to the nearest 0.1 kg in a patient who is over 10 kg.

If they are under 10 kg, I keep either 2 or 3 decimal points.

Rounding to the nearest kilo or more is only for near-adult sized patients in emergency situations.

3,828 Posts

In practice, I don't round until I have completed all calculations. Then, when I round I base the number of decimal places I round to based upon the accuracy of the delivery device. For example, if I am using a 1 mL syringe I round to 2 decimal places, all other syringes I round to 1 decimal place.

As to rounding pediatric weights. For patients 2.5 kg or less, I round to 2 decimal places. For patients less than 40 kg I round to 1 decimal places. As we use adult dosing for patients greater than 40 kg I round to the nearest whole number.

8 Posts

For pediatric oral medications such as Tylenol is the ml to be given rounded to nearest tenth or hundredth ml? Example 4 yr old patient 32 lbs ordered Tylenol 15mg/kg available Tylenol 160mg/5ml how many ml to administer? I would answer give 6.8ml is that correct?

3,828 Posts

Where I practice, yes.

2,577 Posts

Specializes in ED, Pedi Vasc access, Paramedic serving 6 towns.

I would round to the whole number, so 7 mL

3,828 Posts

For pediatric oral medications such as Tylenol is the ml to be given rounded to nearest tenth or hundredth ml? Example 4 yr old patient 32 lbs ordered Tylenol 15mg/kg available Tylenol 160mg/5ml how many ml to administer? I would answer give 6.8ml is that correct?

Yes, this is correct.

In practice, I round the volume that I am preparing based upon the gradation marks on the syringe I am using. Our 1 mL enteral syringes are accurate to 0.01 mL, and our 3, 6, and 12 mL enteral syringes are accurate to 0.1 mL.

Pediatric Critical Care Columnist / Guide

16 Articles; 7,358 Posts

Specializes in NICU, PICU, PCVICU and peds oncology. Has 25 years experience.

Yes. Oral medication syringes are inexact at best.

149 Posts

Use a TB syringe if you're concerned about exact dosing. As far as rounding up or down, consult the MD or pharmacist on the exact, appropriate dose if you have questions . There are many drugs that need exact measurements--less than a tenth of a cc can make a huge difference. Don't take this on yourself--kick it upstairs. It could make a significant difference. Peace.

8 Posts

For pediatric math problems are ml, mcg, mg, and kg rounded to the nearest tenth or hundredth for the final answer?

Pediatric Critical Care Columnist / Guide

16 Articles; 7,358 Posts

Specializes in NICU, PICU, PCVICU and peds oncology. Has 25 years experience.

That will depend on how much of a stickler your instructor/preceptor is. In neonatal patients, the other nurses are going to go to several decimal points for weights and many calculations. In peds, we typically round to the nearest 10th, which is the best one can do when measuring tiny volumes.

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