Download Respiratory Muscle Function

RespiratoryMuscleFunction
Assessmentof
StrengthandEndurance
Load
Work of breathing
Ventilation
Elastic Resistance
(Chest wall and Lung)
Airway Resistance
Capacity
of the respiratory pump
Substrate / O2
Force
Endurance
CNSoutput
Respiratorydrive
Pump
Capacity
Respiratory
musclepump
Loadon
thepump
Ventilatory
Failure
LOAD
RESPIRATORYMUSCLES
● HYPERINFLATION
● OBSTRUCTION
● EDEMA- FIBROSIS
● CHESTWALL
● VENTILATION
● TI/TTOT
CAPACITY
RESPIRATORYMUSCLES
•
•
•
•
•
•
•
•
•
•
•
HYPERINFLATION
CHRONICHEARTFAILURE
HYPERCAPNIA- HYPOXAEMIA
INACTIVITY
NEUROLOGICALCONDITIONS
NEUROMUSCULARCONDITION
CATABOLISM
DRUGS(CORTICOSTEROIDS)
INFLAMMATION
MALNUTRITION
ELECTROLYTEDISTURBANCES
STRENGTH
• MOUTHPRESSURE (PImax,PEmax)
• SNIFFPRESSURE (PSNIFF)
• TRANSDIAPHRAGMATICPRESSURE (PDImax)
• PHRENICNERVESTIMULATION
• CERVICALMAGNETICSTIMULATION
Techniquestomeasurerespiratory
musclefunction
Pdi
Psniff
O
Pmouth
Poes
Maximalvoluntarycontractions
EFFORTDEPENDENT!!!!
Pabd
Measurementofrespiratorymusclestrength
Pressure
Force
Geometry ofthethorax
Mechanical properties (stiffness)
PImax isnotameasure ofmusclecontractile properties
butrather ameasure ofpressure
ALL RESPIRATORYMUSCLESAREINCLUDED
VitalCapacity(%pred)
100
80
60
40
20
0
0
20
40
60
80
100
Inspiratorymusclestrength(%pred)
DeTroyeretal.Thorax1980,35:603- 610.
Maximalstaticpressuresatthemouth
• Measurementofpressuregeneratedbyallin- orexpiratory
respiratorymusclesANDpassiveelasticrecoiloflungsandchest
wall
• Advantages:
– simpleandquick
– welltolerated
– non-invasive
• Disadvantages
– effortdependent
– globalmeasurement
– resultdependentontechnique,andequipmentused
STANDARDISATION OF THE MEASUREMENT:
STANDARDISED
LUNG VOLUME
IS ESSENTIAL
Muscle Length
Elastic properties lung and chest wall
(FRC: ideal elastic properties included)
RV: PImax
TLC: PEmax
FORCE
MUSCLELENGTH-TENSIONRELATIONSHIP
LENGTH
Pressure-VolumeCurve
100
Pcw
%ofVitalCapacity
80
PRS
60
40
EELV/FRC
20
PL
0
-60
-40
-20
0
20
40
60
MouthPressure(cmH2O)
Rahn H,etal.AmJPhysiol 1946
Respiratorypressureandlungvolume
Lungvolume(%TLC)
100
TLC
80
60
FRC
40
Pmus
RV
20
-100
PRS
Pmus
-50
0
Pressure(cmH2O)
50
100
J.T.Sharpetal.ClinChestMed1983,4:421- 432.
Theequipment
Tube
Black&Hyatt(ARRD,1969)
cylinder length15.2cm
internal diameter 3cm
closeddistalend
leak, length15mm,i.d. 2mm
Smaller leaksresult inlargerpressures
(10-20%)
Mayos Chest1991;100:364-366
Leakpreventsglottisclosure,andgenerationofpressurebythe
facialmuscles
Themouthpiece
The mouthpiece
16
14
Pressure (kPa)
12
10
**
Flanged
Tube
**
8
6
4
2
0
PI max
PE max
MEP-measurements
• Checkcontra-indications(e.g.stressincontinence)
• Patientseatedstraight
• Explainthemaneuver:emphasisonFORCE,not
VOLUME
•
•
•
•
•
Fullinspiration
Applymeasuringdevicetothemouth
Forcefulexpirationwithstiffcheeks
Checkquality,andperformance
Repeatuntilreproducible(<5%betweenbest3)
MIP-measurements
• Patientseatedstraight
• Explainthemaneuver:emphasisonFORCE,not
VOLUME,explainthesensationofnotgettingairin
• Fullexpiration
• Applymeasuringdevicetothemouth
• Forcefullinspirationwithstiffcheeks
(creatingavacuum)
• Checkquality,andperformance
• Repeatuntilreproducible(<5%betweenbest3)
ATS/ERSStatement Respiratory muscle testingAJRCCM2002;161:518-624
VOLUNTARYACTIVATION:
FULLCOOPERATIONOFTHE
PATIENTIS REQUIRED*!
*Assessment inICUpatientswillbe
discussed separately
Number of repetitions
PImax (cmH2O)
80
70
60
50
40
1
2
3
4
5
6
7
8
9
10 11 12
20
Fiz etal.Thorax1989;44:419-421
Inspection of pressure/time curve
Start not at RV
Not quick enough
P
Time
Normativedata
9 - 18
Age
Man
Women
19 - 49
50 - 69
-96 ±35
-127 ±28
-112 ±20
-76 ±27
PEmax (cmH2O) 170 ±32
216 ±45
196 ±45
133 ±42
90 ±25
-91 ±25
-77 ±18
-66 ±18
PEmax (cmH2O) 136 ±34
138 ±39
124 ±32
108 ±28
PImax (cmH2O)
PImax (cmH2O)
> 70
Rochester&Arora1983
ATS/ERSStatement Respiratory muscle testingAJRCCM2002;161:518-624
Istheobtainedresult‘(ab)normal’ ?
PImax (cmH 2 O)
180
PImax (kPa)
20
15
10
160
140
120
100
80
60
40
20
5
0
0
0
10
20
30
40
50
0
60
70
80
Age (Yrs)
Wijkstra 1995
McConnell 1998
Uldry 1995
Rochester 1983
Hautmann 2000
Heijdra 1993
Enright 1994
Vincken 1987
15
90 100
30
45
60
75
85
Age (yrs)
Leech 1983
McElvaney 1989
Ringqvist 1966
Wilson 1984
In:Troosters Eur Respir Mon2005
SNIFFPRESSURE
SNIFFPRESSURE
Pes
Pnp
Pmo
ATS/ERSStatement Respiratory muscle testing.AJRCCM2002;161:518-624
ENDURANCE
• SUSTAINEDNORMOCAPNICHYPERPNEA
• INCREMENTALTHRESHOLDLOADING
• REPEATED(SUB)MAXIMALINSPIRATORYMANEUVERS
SustainedNormocapnicHyperpnea
RESPIRATORYMUSCLEENDURANCE
Normocapnic Hyperpnoea
https://youtu.be/lkmGHMRZpKM
Ventilation, L
Sustainedventilation
~60-70%MVV
Tlim,sec
ATS/ERSStatement Respiratory muscle testingAJRCCM2002;161:518-624
Incrementalthresholdloading
Gosselink etal.Thorax1996;51:601-605
ATS/ERSStatement Respiratory muscle testingAJRCCM2002;161:518-624
Respiratorymuscleendurance:constant
workload
Pressureload
(%PImax)
100%
75%
50%
25%
5
10
15
20
Endurancetime(Tlim)
(min)
25
Variable Resistive IMT
Endurancemeasurement
• Patientseatedstraight
• Explainthemaneuver:emphasisonENDURANCE
• Inspiratoryloadapprox.50%PImax
•
•
•
•
Exhalecompletely
Fastandforcefulinspiration
Warm-uptrial3-5minat40%Pimax
Repeatwhentrialisshorterthan3minorlonger
than7minutes
Endurance
Conclusions
• Assessment of respiratory muscle
performance is clinically relevant for
diagnosis, treatment and evaluation
• Assessment of respiratory muscle strength
and endurance is feasible and reliable in
clinical practice
• Practical training is necessary to develop
skills in the assessment of respiratory
muscle strength and endurance