Transcript Nutritional Assessment & Clinical Application Part 2

Nutritional Assessment
Workshop
Nicola Riley
Concord Repatriation General Hospital
[email protected]
Emma McNamara
Concord Repatriation General Hospital
[email protected]
What is Nutritional
Assessment?
“the evaluation of nutrition needs of
individuals based upon appropriate
biochemical, anthropometric, physical,
and dietary data to determine nutrient
needs and recommended appropriate
nutrition intake including enteral and
parenteral nutrition”
- American Dietetic Association
Nutritional Assessment & Clinical
Application - Overall View
Nutrition Management:
• Assessment
• Intervention
• Follow-up / Review
• Evaluation
Consider:
• Health care setting
• Disease / condition
• Lifecycle / physiological state
Nutritional Status
• “Nutritional Status expresses the degree to which
physiologic needs for nutrients are met”
• Optimal NS = Balance between intake and
requirement
• Malnutrition
– state caused by nutritional deficiency
– Reversible by providing appropriate nutrition support
• Deficiency vs Overload
(can be combination of both)
• “whole person” focus, not just disease or condition
focus.
Nutritional Risk
• Critically unwell patients may be well
nourished but high nutritional risk
• Illness, injury, infection




Metabolic derangements
May have significant affect on nutritional status
May lead to malnutrition
Cannot be corrected by nutrition support alone
• Patients at high nutritional risk will require
early nutritional intervention and close
monitoring
Why do we need to
identify malnutrition?
• Malnutrition is associated with:
–  length of stay in hospital
–  complications
–  hospital costs
–  mortality rates
Screening vs Assessment
Nutrition Screening Tools
• Requirements
– quick and simple to administer
– sensitive enough to identify individuals at
risk
– appropriate for client group being screened
– capable of being used by non-dietitians
– reproducible when used by different
observers
– able to guide non dietetic staff into taking
appropriate action for findings recorded
Malnutrition Screening Tool (MST)
Have you lost weight recently without trying?
If NO
If unsure
If YES, how much weight have you lost?
1 – 5 kg (2 – 11 lb)
6 – 10 kg (1 – 1½ st)
11 – 15 kg (1¾ - 2⅓ st)
> 15 kg (> 2⅓ st)
Unsure
Have you been eating poorly because of a
decreased appetite?
If NO
If YES
Total
If the score is 2 or more please refer to the dietitian.
(Ref: Ferguson M et al, Nutrition 15: 458-464, 1999)
0
2
1
2
3
4
2
0
1
The Short Nutritional
Assessment Questionnaire
(SNAQ)
Question
Score
Did you lose weight unintentionally?
>6kg in the past 6 month
3
>3kg in the past month
2
Did you experience a decreased appetite
over the past month?
Did you use supplemental drinks or tube
feeding over the past month?
1
1
Nutritional Assessment Tools
• No single / standard way of assessing nutritional
status
• Various validated assessment tools developed
– some disease specific
– some age specific
• 2 examples
– Mini Nutritional Assessment (MNA)
– Subjective Global Assessment (SGA)
Mini Nutritional Assessment
(MNA)
• Screening and Assessment tool for the
identification of malnutrition in the
elderly
• Considers:
– Dietary Intake – foods, patterns
– Weight change, BMI, Muscle circumferences
– Functional impairment, Independence,
Living arrangements
– Psychological issues, Self assessment
Subjective Global
Assessment
• Valid assessment tool
• Strong correlation with other subjective
and objective measures of nutrition
• Highly predictive of nutritional status in a
number of different patient groups
• Quick, simple and reliable
Subjective Global
Assessment…features
• Medical History
– Weight change
– Dietary intake
– GI symptoms
– Functional impairment
• Physical Examination
– Loss of subcutaneous fat
– Muscle wasting
– Oedema and ascites
Subjective Global Assessment
…Classifications
A
Well nourished
B
Moderately malnourished or
suspected of malnutrition
C
Severely malnourished
Full Nutrition Assessment
Step 1…Data collection
• Systematic Approach
• Assessment based on
clinical/psychosocial/physical information
–
–
–
–
Dietary
Anthropometric
Biochemical
Physical
• Including
– Subjective (eg. signs/symptoms of nutritional
problem, appetite)
– Objective (eg. Lab results)
Data Collection…
An Example… A B C D E
A
B
C
D
E
Anthropometry
Biochemical Data
Clinical signs and symptoms,
medical condition
Dietary Intake
Exercise (Energy balance –
expenditure)
Consider current level, history and changes
Anthropometry
• Height
• Weight
• Weight history /
pattern
(% weight change)
• Weight for Height
• BMI
• Growth Pattern,
head circumference
(paediatrics)
•
•
•
•
•
MAMC
TSF
Waist circumference
Hip circumference
WHR
Be aware of fluid
status, presence of
oedema.
Anthropometry – Body
Composition
Muscle, Fat, Bone, Water
Body Mass:
• LBM – Body mass
that contains small
% (~3%) essential
fat
[Essential fat +
Muscle + Water +
Bone]
• Fat Free Mass (FFM)
Fat Store:
• Essential Fat for
physiological
function, eg. fat
stored in muscle,
liver, heart
• Storage fat in
adipose tissue –
visceral fat and
subcutaneous fat
Body Compostion cont’d.
• Practical Methods in Clinical Setting:
– Weight, height & weight Hx
– Skinfolds, circumferences
• TSF, MAMC,WHR
• More precise, occasional use:
– Bioelectrical Impedance Analysis (BIA)
• FFM, % body fat
– Dynamometry (grip strength)
• Precise, Expensive, Research purposes:
– CT, MRI, Dexascan, TBK,TBN
Biochemistry & other Blood Tests
(See also disease/condition specific lectures)
• Objective measures
• No single test is diagnostic
• Consider “normal / recommended range” for
various and combination of conditions, eg.
age, gender, physiological state, disease type
and stage
• Consider clinical significance of test result
• Test result may reflect immediate intake (eg
glucose) or long term status (HbA1c)
Other factors to Consider…
• Other factors can mask/influence
test results eg.
– Acute phase response due to stress /
injury ( reduced albumin)
– GI bleed (higher urea)
– blood transfusion (higher serum K
and Hb)
– Surgery (lower Hb and albumin)
Acute Phase Response
Inflammatory processes (shock, trauma,
sepsis)
liver protein synthesis shifts from
visceral proteins, e.g. albumin and
prealbumin to acute phase proteins
Visceral proteins may reflect ‘nutritional
risk’ not nutritional status
Nutritional Indicators
• Ideal indicator or marker is sensitive
and specific to nutritional intake
Commonly Used “Nutritional Indicators”
–
–
–
–
Albumin
Pre-albumin
Transferrin
Retinol-binding protein
Albumin
• Synthesised in the liver
• May be useful indicator of nutritional
status in “healthy” person.
• Not a good indicator of protein status
during critical illness (due to acute
phase response)
• Long half life (14-20 days) and large
body pool  slow to respond to
improvements in clinical status
Factors Affecting Serum
Albumin Levels
Increased in:
– Dehydration, blood transfusions,
exogenous albumin
Decreased in:
– Overhydration, hepatic failure,
inflammation, infection, metabolic
stress, post-op, bed rest, pregnancy,
nephrotic syndrome.
Pre-albumin
• Also known as Transthyretin, thyroxine binding
protein.
• Synthesised in the liver
• Relatively short half life (2 days)
• Negative acute phase reactant -  with
inflammatory response
• May be useful in healthy population
Transferrin and RBP
Transferrin
– Half life 8-10 days
– Poor correlation with nutrition status
– Involved with iron transport, influenced by
iron status
Retinol Binding Protein (RBP)
– Half life 12 hours
– Affected by renal function, Vitamin A and
Zn status
– Unreliable measure of nutritional status
Biochemistry & other Blood Tests,
cont’d
(See also disease/condition specific lectures)
• Interference – drugs, sampling
• Nutrient-nutrient interactions, drugnutrient interactions
• Be aware of hydration status
• Must interpret lab results with other
nutritional parameters
Clinical issues to consider:
• Medical history, treatment and
medications
• Significant factors affecting nutritional
intake
• Fluid balance – input and output, Bowel
habits
• Physical assessment of nutritional
status
• Clinical signs and symptoms
Clinical Signs and Symptoms
Signs
• Subjective,
impression
• Descriptive,
observation
• Appearance
• Visual examination
• Needs clinical
judgement
• Eg muscle wasting,
malnutrition
Symptoms
• Recall, report by
subjects
• Descriptive
• Eg nausea, itchiness,
diarrhoea, anorexia
Dietary Intake
(See relevant lectures in dietary intake, RDIs, etc)
• Is intake meeting requirement?
– Basic nutrition adequacy
– Special requirement / disease / conditions
• Consider factors affecting intake
• Consider clinical, nutritional and psychosocial issues
• Methods of collecting information/data
• ?Relevant and practical
Exercise – Energy Balance
• Nutrition and exercise closely linked –
metabolic and physical fitness
• Functional capacity and Nutritional status
– Correlation between muscle mass and physical
strength, nutritional status and physical function
• Energy Balance to attain optimal weight and
body composition
• Bed Rest / Inactivity
– Negative effects on muscles, bone and CV system,
eg. 8 g protein loss / day of bed rest
– Exercise – affects on appetite, bowel function
Estimating Nutritional
requirements
Consider
•Energy
•Protein
•Fluid
•RDIs for micronutrients
Estimating Energy
Requirements
• Indirect Calorimetry
– preferred method
– use of a metabolic monitor/cart
– measures respiratory gas exchanges
– Differences in oxygen and carbon dioxide content
between air going in and air coming out 
respiratory exchange  energy expenditure
(Ref: Mann & Truswell(ed) Essentials of Human Nutrition, Chap. 5)
Harris Benedict Equation
• Devised in 1919
• Multiple regression analysis of the gender,
age, height and weight of 239 healthy
volunteers
• Recent review of data and methodology - still
valid (Frankenfield et al, 1998, JADA)
• Basal energy expenditure (BEE)
= energy expended by a fasting
subject at rest in a ‘thermoneutral’
environment
Harris Benedict Equation
Males (kJ/24hr)
BEE = 278 + (57.5 x W) + (20.9 x H) - (28.3 x A)
Females (kJ/24hr)
BEE = 2741 + (40.0 x W) + (7.7 x H) - (19.6 x A)
W = actual weight in kg, H = height in cm,
A = age in years.
Schofield Equation
• Original equation (Schofield, 1985) derived
from a study group of 5000 healthy adults
• Modified by COMA Panel on Dietary
Reference Values (UK Dept of Health, 1991)
• excluded some data from developing nations
• additional equations for people over age of 75
yrs, based on Italian data
• Limitations - ?validity with obese clients,
some ethnic groups, ?applicable to
Australian population.
Original Schofield Equations
(1985)
Males
Females
Age (yrs) kJ /24hr
Age (yrs) kJ / 24hr
15-18
74W + 2754
15 - 18
56W + 2898
18-30
63W + 2896
18-30
62W + 2036
30-60
48W + 3653
30-60
34W + 3538
60+
49W + 2459
60+
38W + 2755
Modified Schofield Equations
(1991)
Males
Females
Age (yrs)
kJ /24hr
Age (yrs)
kJ / 24hr
10-17
74W + 2754
10-17
56W + 2898
18-29
63W + 2896
18-29
62W + 2036
30-59
48W + 3653
30-59
34W + 3538
60-74
50W + 2930
60-74
39W + 2875
75+
35W + 3434
75+
41W + 2610
Estimating Energy requirements
• Estimate BMR/BEE for healthy adult
using predictive equation
• Adjust for stress using injury factor
• Adjust for activity using activity
Energy requirement = BEE x Injury/Stress factor x Activity factor
Activity Factors
Resting sedated +/- ventilated
Resting conscious
Bedrest (moving self around bed)
Light (mobilizing around ward)
Moderate (regular, intense physio)
1.0
1.1
1.2
1.3
1.4
Injury Factors
Medical (IBD, liver/pancreatic d)
Surgical (transpl, fistula)
Cancer (tumour/leukaemia)
Trauma (or minor burns)
Sepsis (or other major infection)
Major burns
1.1-1.2
1.2-1.4
1.2-1.4
1.2-1.4
1.3-1.4
1.5-1.6
* Refer also to nutrition support and specific
clinical lectures
Estimating Protein /
Nitrogen Requirements
• From measuring Nitrogen losses from the body (urine,
faeces, fistulae/drain losses, burn exudates)
– Urinary nitrogen excretion can be estimated by
measuring urinary urea nitrogen(UUN) excretion
from a 24hr urine sample.
– Urea production influenced by liver failure, sepsis,
stress
 insensitive and unreliable in clinically unstable
patients
Estimating Protein /
Nitrogen Requirements
Using RDA’s
– Healthy adult
0.75g/kg BW
Increased metabolic needs during periods of stress
– Mild/intermediate stress state
eg surgery, fractures
1-1.5g/kg BW
– Cancer
1.2-1.5g/kg BW
– Multiple trauma,
1.5+/kg BW
extensive burns(>30%)
Fluid Requirements
Different methods used:
• 35 – 45 mL/kg body weight
– 30mL for older adults
– 40 – 45 mL for active young adult
• 0.24mL/kJ energy given
• 1500mL + add 20mL per
additional kg over 20kg