Review Guide for Test 4

When studying for your Module 4 test on Monday, be sure to:


o†† memorize the formulas, including UNITS, for Clark's Rule, Fried's Rule, and the Body Surface Area (BSA) rule


o†† notice that Fried's Rule is only applicable to children 24 months (2 yrs.) and under


o†† notice that Clark's rule weights are in pounds, not kilograms; if the weight is given in kg, obviously you'll need to convert to lb. before applying Clark's Rule


o†† understand the difference between the two BSA charts that are displayed together on p. 229;  if they give both height and weight, use the HEIGHT, WEIGHT, and [B]SA columns; if only a "normal height for a weight of 30 pounds" is given, use the boxed nomogram just to the left of center


o†† when using the full-blown height and weight BSA nomogram, be sure to use the correct scales for height (cm or in, as appropriate) and weight (lb or kg, as appropriate)


o†† notice that the boxed nomogram on p. 229 converts weight in POUNDS to a BSA estimate; if patient weight is given in kg, you'll need to convert to lb.


o†† notice that BSAs range from 0.10 m^2 (meters squared or square meters) to 2.0 m^2; the boxed nomogram in the book does not use the "leading zeroes before all quantities less than one" rule, so it's easy to mistakenly give 45 m^2 instead of 0.45 m^2 for the BSA of a child of normal height for his/her weight of 20.5 lb.  (Obviously 45 m^2 is the area of all the walls, plus floor and ceiling of a fairly large classroom, but it's easy to grab the "45" and miss the decimal point that makes it 0.45 m^2.)Iíll put a corrected version of the nomogram on the test, but mark your books with 0.xx m^2.

o†† download the Guide for Calculations with Body Surface Area (BSA)  from my website;  the BSA problems aren't hard at all, but the two major categories of BSA calculations need to be recognized and acted upon


o†† download the information on dosage range or "Is it safe?" problems;  be sure that the units of the dosage range (mg/dose or mg/day, or even mL/dose or mL/day) are made to match the units of the order (mg/dose, mg/day, or whatever


In general, watch the units on the test; be sure that kilograms divide out kilograms and pounds divide out pounds; some of the pediatric dosages have the unusual property of stating dosage rates in mg/lb instead of mg/kg, and some of the infusion rates are in mcg/lb/min.  If the patient's weight is in pounds already in these problems, don't convert to kilograms.  Likewise, if the patient weight is in kilograms, convert to pounds if the rate is "per pound."


I hope this helps!