Muscle ultrasound for nutritional

1. Muscle Ultrasound For
nutritional
assessment
HOSSAM ATEF
ASSOCIATE PROF OF ANESTHESIA&ICU
SUEZ CANAL UNIVERSITY

2. Muscles weakness
 Immobilization
 Dysfunctional central &peripheral neural
signals
 Metabolic & physiological dys-regulation of
skeletal muscle
 Loss of muscle mass
 Degradation in skeletal muscle architecture

4. Sarcopenia
 Definition : A geriatric syndrome characterized by
progressive & generalized loss of skeletal muscle mass &
function with a risk of adverse outcomes
 Sarcopenia staging
 Presarcopenia (low muscle mass only
 Sarcopenia low muscle mass + low muscle strength or
low physical performance
 Severe sarcopenia low muscle mass + low muscle
strength + low physical performance

5.  It is related
 ObesityOsteoporosis / Fracture
 Metabolic syndrome Blood sugar abnormality
 Cardiovascular disease
 Chronic liver disease
 Chronic kidney disease
 Cognitive impairment/ Depression

6. WHICH PATIENTS
 GUIDELINES OF NUTRITION
 NUTRITION FOR CANCER PATIENTS
 NUTRITION FOR ACUTE &CHRONIC KIDNEY
 NUTRITION FOR ACUTE PANCREATITIS
 NUTRITION FOR CRITICALLY ILL OBESE
 ALBUMIN STORY IN ICU
 NUTRITION IN TBI
 HEN

7. Muscle weakness….why a
serious problem
 independently predict clinical outcomes in ICU as ICU
patients had pronounced edema & fluid shifts ; Skeletal
muscle wasting in ICU often masked by fluid retention
 Anthropometric assessing body mass & composition
changes not applicable
 (all techniques assume a normal state of hydration)

8.  Most of the used measures Lack of specificity &variability
 Weight lost during hospitalization may regained within 1
year of ICU discharge but as fat mass rather than lean
mass

11. Muscle atrophy .... Time of
occurrence
 Still debate
 Within first 2-3 weeks
 Between 5 and 39 days (median 7)
 Approximately 8 to 30% loss of muscle within the first 7–10
days ICU admission
 Within 3 days
 … Whenever it is started, it progressively worsens
thereafter

12. Methods for Muscle
Quantification
 Body mass index (BMI)
 Bioelectrical impedance analysis (BIA)
 Dual-energy X-ray absorptiometry (DEXA)
 Computed tomography (CT)
 Magnetic resonance imaging(MRI)
 Ultrasonography

13. Skeletal muscle ultrasound
 Skeletal muscle ultrasound is not a new technique
 For > 30 years (Since the early 1980s), it has been used
in the ICU setting, in neuromuscular disease
 Skeletal muscle ultrasound focused on understanding
muscle loss in
 1- Chronic disease
 2-Aging

14.  Now it is used in the ICU to accurate muscle quantification
&for longitudinal analysis & is valuable for
 Understanding the underlying mechanisms of muscle wasting
 Characterizing metabolic & functional changes in lean tissue
 Assessing the success

15. US Muscle…Advantages
 Completely non-invasive & Absolutely safe
 Radiation-free instrument
 Handy, accessible in most clinical settings Inexpensive
tool (relatively)
 A clinician without prior US Experience need 2 weeks
 providing & correlates well with quantitative & also
qualitative assessment

18. Identification of landmarks
 Appropriate training needed for consistent identification of
landmarks.
 Standardized protocols on how to identify anatomical
landmarks for measurement are lacking.
 Reporting standards (in publications) are lacking .
 Reliability testing for landmark is either lacking or
included] within the entière data acquisition process (i.e.,
probe placement, image analyses

19. Muscle site
 Different muscles are often measured across different
studies (rectus femoris vs. vastus lateralis., upper limb vs,.
lower limb, or a combination).
 Different methods are used for muscle quantity
assessment (cross sectional area ? muscle layer vs
thickness
 Best site to capture muscle groups consistently are unclear
(i.e. mi1d-thigh versus 2/3 femur length versus 3/5 femur
length)

20. US Muscle…Disadvantages
 Measurement differences are probably:-
 Operator-related, such as oblique imaging of the RFCSA
or
 Placement of an inaccurate cursor outline for area
calculation
 Probe excess compression likely introduce additional
measurement variability

21.  Affected by limb fat:
 visualization of the muscle border is difficult when:-
 More subcutaneous fat present (RFCSA may unmeasurable
in severely obese)
 Depleted body fat grossly (problematic visualization of
intermuscular septa

22. Requirements for Muscle US
Measurement
 Room temperature of 25°C (required to take off the heavy
coats)
 B-mode
 US settings (Depth, Gain and Focus) were standardized for
muscle examinations
 Depth set to where the bone could be discerned for
orientation

23.  The transducer → linear
 → curvilinear only if large limb size (to visualize section
completely)
 Excess contact gel applied (↓underlying soft tissue
distortion) (↓depression of the dermal surface)
 some researchers used full maximal probe compression on
underlying tissues
 to remove confounding effect of edema [apply as much
pressure as patient’s sense of pressure/ pain]

24.  Probe head perpendicular to the major axis of the limb surface
= to the long axis of the muscle
 After freezing the US image:-
 The measurement points marked with indelible ink (consistency
& facilitate subsequent measurements)
 the US measurement to the nearest 0.01 cm
 The participants were asked to take rest for 20 minutes after
each US measurements
 2-3 consecutive measurements were taken for each muscle (use
the mean of 3 measurements)
 For both limbs
 If lower limb fractures, measurements were taken on the
contralateral limb only) The dominant limb

25.  Thickness (MT)
 Use on screen calipers and taken as:
 Vertical distance between the inner edge of the muscle
 From the bone upper margin to the deep fascia of the
muscle lower boundary
 Cross-sectional area

26.  Gentle contraction-relaxation maneuvers employed to
delineate muscle septa prior to image acquisition The
operator minimize Oblique imaging to obtain the smallest
cross-sectional image
 On a frozen image with by a movable cursor
 the inner echogenic line of the rectus femoris was outlined
by a movable cursor
 RFCSA was calculated by a planimetric technique

27. Lower limb US
 Patient position: Supine for Quadriceps group Prone for
Gastrocnemius
 Both Legs rested supported in passive extension &neutral
rotation
 Muscle selected:
 Rectus femoris
 Rectus femoris + Vastus intermedius
 Gastrocnemius

28. The Quadriceps group
 Rectusfemoris
 Point of measurement: The distance from the anterior superior iliac
spine to the patella superior border (upper pole ):
 Midpoint (1/2)
 Lower 1/3
 Lower 3/5 (three-fifths) [The highest point in thigh that entire RF
cross section could be visualized in a single field; other muscles of the
quadriceps group could not be encompassed in this manner

32. GASTROCNEMIUS
 Cross-sectional area of the Gastrocnemius measurement
 Prone position
 Legs passive extension & neutral rotation & relaxed
 Feet hanging off the examination bed
 Probe position:-
 The medial head of the gastrocnemius muscle medial cross
section
 found the largest CSA as the standard section, marking the
corresponding body surface

35. Upper limb US
 Arm ultrasound measurements
 Supine ,Arm in passive extension , Forearm supinated
 arm bent 90 degrees at the elbow while the actual measure was
performed with the arm hanging loose or stretched out along
the bed
 Probe position: midway between the superior & lateral
projection of the acromion process of the scapula and the
proximal and lateral border of the head of the radius

36.  Technique:-
 The flexor compartment of the mid-upper arm → muscle
thickness
 perpendicularly from the bone to the superficial fat-muscle
interface

37.  Muscle US Measurements
 Quantitative parameters :
 Anterior–posterior diameter (AP diam)
 Lateral–lateral diameter (LL diam)
 Cross-sectional area (CSA) (computed from the perimetral
contour of the muscle section)

38.  Muscle thickness (MT)= Muscle layer thickness (MLT)
 distance between the upper and deeper aponeurosis on the
axial view
 Muscle cross-sectional area (CSA): Typically describe its
contraction

39. Physiological cross-sectional
area (PCSA)
 Is the area of the cross section of a muscle perpendicular to its
fibers (generally at its largest point)
 In a pennate muscles
 When a muscle contracts & shortens→ more muscle fibers can be
packed in parallel→ by ↑pennation angle → so with smaller range
of motion; allowing muscle higher force production although fiber
angle to action direction
 (the maximum force in that direction is somewhat less than the
maximum force in the fiber direction

40. Muscle cross-sectional area
(CSA)
 Anatomical cross-sectional area (ACSA):
 Is the area of the cross section of a muscle perpendicular to
its longitudinal axis
 In a non-pennate muscle

42. Muscle physiological cross-
sectionalarea (PCSA)
 In a pennate muscle:-
 (muscle with fascicles attached obliquely (slanti
 ng position) to its tendon)
 In a non-pennate muscle PCSA coincides with ACSA as
fibers are parallel to the longitudinal axis
 Does not accurately represent the number of
 muscle fibers in the muscle