Common Formulae for use in Paeds

 

COMMON FORMULAE :

                         

Many Drugs are given according to Surface Area of Pt.

Formula to Calculate Surface area from weight (x)  is :

S.A = (4x + 7) / (90 + x)

       = _____ m2

Fluid  rate

what are the formulas to calculate drops rate of a simple dripset, B.T set , and microburette ???

 In in simple drip set 15 drops = 1 ml

 In Blood Tx Set 12 drops = 1ml

 In microdrip set (pediadrip) 60 micro-drops =1 ml

Various Formulae are given below.

 1)   Simple Calculation Formula is:

                    Fluid in ml *drops/time in min

2) Drop index Formula is :

                   Fluid in ml ×drop index/time in min                    

  the drops will come out for one minute !

  drop index is 15 for dripset ,, 60 for M.B (pediadrip) and 10 or BT set.

3)  FOR BURETTE.. FLUIDS(ml)/TIME(hrs)

4) for DRIP.............FLUIDS(ml)/TIME(hrs) MULTIPLY BY 1/4.....e.g to give 500 ml in 8 hrs it will be approx 62 micro drop/min or 15 macrodrops.

Calculation of GFR

Many drugs , specially antibiotics need adjustment in their DOSES, or their INTERVALS of administration . This is decided on the basis of  GFR , which may be calculated as:

GFR = kL/SrCreatinine

Where K is constant

L is length/height

Sr creatinine

K values:

LBW infants in 1st year	0.33
Term AGA in first yr	0.45
Children and adolescent girls	0.55
Adolescent boys	0.70

Check at the end of Harriet Lane : Drugs in Renal Failure to see adjustment of DOSES, or intervals or BOTH.