meccanica toraco-polmonare: dalla fisiologia alla misura · meccanica toraco-polmonare: dalla...
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Meccanica Toraco-Polmonare:
dalla fisiologia alla misura
Lorenzo Lorenzo AppendiniAppendini
Fondazione “Salvatore Maugeri”, IRCCS, Fondazione “Salvatore Maugeri”, IRCCS,
Istituto Scientifico di Veruno, Divisione di Pneumologia Istituto Scientifico di Veruno, Divisione di Pneumologia
Veruno (NO), Italy.Veruno (NO), Italy.
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Gastric Pressure
Esophageal Pressure
Airways Opening
Pressure
Ampl.
Ampl.
Ampl.
Ampl.Tracheal Pressure
Pga
Pes
PaoPtr
Respiratory Mechanics - Experimental Setup
Ampl.Tracheal Pressure
Pneumotach
3 CH EMG
Flow
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IPERINFLAZIONE DINAMICA PEEPi PEEPi (Pressione Positiva di Fine Espirazione intrinseca)
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MECCANICA RESPIRATORIA MECCANICA RESPIRATORIA DURANTE RESPIRO SPONTANEO
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Gastric Pressure
Esophageal Pressure
Airways Opening
Pressure
Ampl.
Ampl.
Ampl.
Ampl.Tracheal Pressure
Pga
Pes
PaoPtr
Respiratory Mechanics - Experimental Setup
Ampl.Tracheal Pressure
Pneumotach
3 CH EMG
Flow
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Computed Parameters
• inspiratory time per breath (TI = t2-t1)
• expiratory time per breath (TE = t1*-t2),
• respiratory cycle duration (TT= TI + TE)
•
A zero crossing algorithm detects the beginning time of the
inspiratory and expiratory phases (t1, t2 respectively). The onset
of Pdi pressure is computed to measure the time (t0) in which
the transpulmonary and the transdiaphragmatic pressures begin
to leave the end expiratory level. (Fig.2)
Reference Points and Parameters
5
10
15
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
1 2 3 4 5 6
-0.1
0
0.1
0.2
0.3
0.4
0.5
VT/2
dP3
Flow(L)
PL=Pao-Pes (cmH2O)
Volume (L)
dP0
VT
dP2dP1
dF2 dF1
• respiratory cycle duration (TT= TI + TE)
• duty cycle (TI/TT)
• tidal volume (VT)
• breathing frequency ( f = 60 / TT )
• minute ventilation (V’E = VT x f)
• rapid shallow breathing index (RSB = f / VT)
• PEEPi both on esophageal (PEEPi) and trans-
diaphragmatic (PEEPi,corr) pressure
• Dynamic lung elastance EL,dyn=dP0/VT
• Mean resistance RL = dP1/dF1
• Mean inspiratory resistance RL,insp = (dP2 – dP3)/dF2
• Pressure Time Product on Pdi and Pes (PTPdi and PTPes,
respectively)
0
5
10
15
20
25
30
0 1 2 3 4 5 6
-10
-5
0
1 2 3 4 5 6
-20
-15
-10
-5
0
5
10
1 2 3 4 5 6
PEEPi
PEEPi (1,2), Resitive (3), Lung (4) and Chest Wall (5) elastic components of PTPes
5
1 2 3
4
PEEPi,corr
t1 t4 t2 t5
Pdi=Pga-Pes (cmH2O)
t0 t6
Pes (cmH2O)
t1 t2t0 t6
t1*
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PmusPmus == ((VVTTxExE + V’+ V’xRxR + + PEEPPEEPii))
Respiratory workloadRespiratory workload
NORMALS
Inspiratory muscleInspiratory muscleperformanceperformance
NMD
COPD
Aldrich TK, Prezant DJ. 1994Aldrich TK, Prezant DJ. 1994
Ventilatory Ventilatory
failurefailure
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Respiratory workloadRespiratory workload
NORMALS
Inspiratory muscleInspiratory muscleperformanceperformance
Pmus = VPmus = VTTxE + V’xR + PEEPxE + V’xR + PEEPii
COPD
NMD
MVMV
MVMV
Pmus + Paw = VPmus + Paw = VTTxE + V’xR + PEEPxE + V’xR + PEEPiiwww.aitfr
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