Chapter 16 3/21/2001
Last class we started talking about growth charts. Growth grits are
separate for boys and girls, and we are looking at Ht, wt, and head circumference as
compared to age. Values in the chart can vary within +/- 10th percentile . We use these
growth grids mostly in long term care facilities,.such as nursing homes, outpatient
community centers and WIC. The most important thing to remember, when dealing with
growth charts, as we have already mentioned last time, is to make sure that all
parameters are at the same percentile. If for example wt becomes a problem , you do not
want to put the child on a diet. What you want instead, is to keep the child at the same
percentile and have the height to catch up with the weight.
Growth charts used previously (developed in 1977), were revised in 2000
Why were CDC growth charts rewised ? Click here
Click here for Power point slide show presentation on CDC Growth charts here
If you are interested in learning more about growth charts, follow the links in
the text of chapter 16
Probably the most important anthropometric measurement that we are interested in
is weight. We are mostly concerned with actual body wt. This wt we then
compare with usual body wt, and ideal body wt. From those the usual, and actual body wt are the most important ones.
In the hospital we are looking at protein kcal malnutrition which is defined as
deficiency. For that reason, if somebody is for example obese, you cannot be looking at
the patient as having excess, and consider beneficial if he loses 20lb over the course of
a month. This kind of weight loss still needs to be viewed as significant weight loss,
that is putting the patient at risk for prot kcal malnutrition. From that follows that,
if you are calculating kcal need, you are always using actual body wt . In case the pt is
obese you are using adjusted body weight.(actual- usual) x 0 .25) + IBW = adjusted
BW
%UBW / %IBW
When we are doing assessment we are calculating
a) percentage of usual body weight %UBW = actual BW
UBW
b) percentage of ideal body weight %IBW = actual BW
IBW
What is considered significant wt loss is loss of 2% of BW over a week
5% a month
10% in 6 months
Other criteria are: 92% is a risk factor
90-92% is moderate risk
<90% is high risk for prot-kcal malnutrition
You really have to be careful when you are looking at IBW and UBW. The person
may be 100% at his/her IBW, but when you compare it to his/her UBW, you find out
that there was significant weight loss within a short period of time, which puts
this person at risk.
Calculating BMI
BMI- body mass index, is a measurement that is used to determine over-weight
and under weight, and helps to determine risk factors associated with high or low
numerical values. This measurement is widely used in extensive care facilities.
To calculate BMI we need to first convert wt(lb) into kg and Ht(inches)
into meters
a) lb into kg = > 1 lb = 2.2 kg
b) convert height into meters == > 1 feet = 12 inches = 1)convert feet into inches
2) add remaining inches
3) multiply by 2.54
4) move decimal by 2 places
to the left.
BMI = wt(kg)
ht(m)2
Example 1 : Male Ht = 5'9"
wt = 154 lb
1) 5(feet) x 12(12 inches in 1 feet) = 60 inches
2) 60 + 9(remaining inches he is 5'9") = 69 inches
3) 69 x 2.54 = 175 cm
4) To convert cm into meters move decimal point by 2 places to the left
= >> 1.75m
154 lb = 154
2.2 = 70 kg
Now we can calculate BMI using the above formula
BMI = wt(kg) = 70(kg) = 70(kg) = 22.84 = 23
ht(m)2 1.75(m)2 3.06
Example 2: Male Ht = 6'3" = 1.90 m
Wt = 240 lb = 109 kg
BMI = 109/(1.90)2 = 30
When we are measuring body, we are looking at
UBW = usual body weight
IBW = ideal body weight
ABW = actual body weight
BMI= body mass index
TFF(TSF) = triceps fat fold also known as triceps skin fold
Here we are measuring how much skin we can take off the muscle. For that we
have to do three measurements to get accurate reading. This measurement helps us to
determine percentage of adipose tissue
To measure somatic protein, we are using technique called Mid arm muscle
circumference.(MMC) To measure mid arm muscle
circumference we need to first measure circumference
around triceps . From that we subtract the skin fold
measurement and the result we multiply by a bone factor
MMC = (muscle circumference - TFF) x factor
When we are doing assessment on somebody we need to know:
a) his kcal need, and kcal intake ( intake we find by doing diet history)
b) his protein need, and protein intake
c) %UBW
d) %IBW
e) BMI
Example Male Ht = 5'11" AF= 1.2
ABW = 135 lb IF = 1.4
UBW = 165 lb
Age = 49
Calculate
1) kcal need
2) protein need
3) % UBW,
4) %IBW
5) BMI
1) HB = 66 + (13.7 x wt(kg)) + (5 x ht(cm)) - (6.8 x age)
=(66 + 840 + 900 ) - 333
= 1806 - 333
= 1473 kcal
Total energy need = HB x AF x IF
= 1473 x 1.2 x 1.4
= 2474 kcal
2) a) Protein need = wt (kg) x IF B)Protein need = (2474 : 150) x 6.25
= 135(kg x 1.4 = 16.49 x 6.25
2.2 = 103.08 = 103 gm
= 61.36 x 1.4
= 85.9 gm
3) %UBW = ABW
UBW
= 135 / 165
= 0.82 x 100 = 82% == > this person is cachectic
4) %IBW
IBW = 106 + (6 x 11)
= 106 + 66
= 172 cm ======= >>> %IBW = ABW
IBW
= 135 / 172
=0 .78 x 100 = 78% ==== > person is
underweight
BMI = wt (kg) / Ht ( cm)2
= 61.36 / (1.82) 2
= 18.4