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CARDIOPULMONARY INTERACTIONS
CARDIOPULMONARY INTERACTIONS
Evaluation and Treatment of
Low Cardiac Output Syndrome,
RV Dysfunction, and
Cardiopulmonary Interactions
‘Right heart failure’
Neonatal and Childhood Pulmonary Vascular Disease
San Francisco 2012
Right ventricular myocardial
function
Right ventricular loading
conditions and cardiac output
Role of lungs
CARDIOPULMONARY INTERACTIONS
CARDIOPULMONARY INTERACTIONS
Positive pressure ventilation
The normal circulation
Left ventricular failure
Reduced O2
consumption
PEEP for oxygenation
/recruitment with
pulmonary oedema
Lower LV afterload
Spontaneous inspiration and the right
heart:
Modest reduction in mean
airway pressure
Diaphragmatic descent increased IAP
Increased venous return
↑ Stroke volume
CARDIOPULMONARY INTERACTIONS
CARDIOPULMONARY INTERACTIONS
Normal: increased mean airway pressure
Normal: increased afterload
Change in CO
PEEP 20cm
no PEEP
Pleural
Pressure
-15%
mmHg
-16%
PVR
Dyne.s.cm
RVEDV
mls
Stroke
volume
-6%
ml/beat
Cournand, 1947
Henning J Appl Physiol 1986
CARDIOPULMONARY INTERACTIONS
CARDIOPULMONARY INTERACTIONS
RV afterload
Lung inflation and the right heart:
Pressure-volume relations
Whittenberger 1950
• Matched
to low
Left ventricle
hydraulic impedance
Right ventricle
Maximal stroke work
limited
Ventricular volumes and
ejection fraction
sensitive to acute
changes in afterload
Afterload sensitivity x45 of LV Volume
Volume
Redington et al. Br Heart J 1989
CARDIOPULMONARY INTERACTIONS
CARDIOPULMONARY INTERACTIONS
Superficial fibres
Myocardial crosstalk
Sanchez-Quintana et al. Heart 1999
CARDIOPULMONARY INTERACTIONS
Aortic constriction leads to increased
RV stroke volume and developed
pressure during experimental PA
constriction
Yamashita et al. Jpn Circ J 1989
Belinkie et al. Circulation 1995
Apitz C et al. Thorac & Cardiovasc Surg 2011
Damiano et al. Am J Physiol 1991
CARDIOPULMONARY INTERACTIONS
Acute RV failure
Apitz C et al. Thorac & Cardiovasc Surg 2011
CARDIOPULMONARY INTERACTIONS
CARDIOPULMONARY INTERACTIONS
Acute RV failure
Acute RV failure
RV Contractility
RV Contractility
Isolated acute RV systolic failure:
Post bypass (e.g.Ebsteins)
Post transplant
RV infarction
Apitz C et al. Thorac & Cardiovasc Surg 2011
Apitz C et al. Thorac & Cardiovasc Surg 2011
CARDIOPULMONARY INTERACTIONS
CARDIOPULMONARY INTERACTIONS
RV contractility
RV pressure-volume relations
Unloaded
RV emax
Conductance catheter
Brief period of CPB
Reduced ESPVR
Volume
Volume
Redington et al. Br Heart J 1989
Adverse effects
of RV
afterload amplified in
previously normotensive RV
Brookes et al. JTCVS 1999
CARDIOPULMONARY INTERACTIONS
CARDIOPULMONARY INTERACTIONS
RV afterload proportional to:
Negative pressure ventilation
Pulmonary arteriolar smooth
muscle tone
Pulmonary venous pressure
Lung volume
Mean airway pressure
Hyek oscillator
Comparison of
NPV vs IPPV
Direct Fick
Respiratory mass
Spectrometry
Lara Shekerdemian
Shulze-Neick. Circulation 2003:103; 167-73
CARDIOPULMONARY INTERACTIONS
CARDIOPULMONARY INTERACTIONS
Hyek Oscillator
Effect of IPPV
IPPV and the right heart:
Comparison of IPPV and NPV in
‘normal’ children
Comparison of IPPV and NPV in
children after ‘simple’ heart
surgery
IPPV
Paw (cmH2O) = + (5-8)
NPV
Paw (cmH2O) = - (6-9)
11%
28%
Shekerdemian et al. Heart 1997;78:587-93
CARDIOPULMONARY INTERACTIONS
CARDIOPULMONARY INTERACTIONS
Natural models
Restrictive physiology-Postop
RV dysfunction after
tetralogy repair
Fontan circulation
Lower urine output
Cool peripheries
Lower pH
The heart and lungs as a
haemodynamic
unit
Cullen et al. Circulation 1995; 91:1782-9
CARDIOPULMONARY INTERACTIONS
CARDIOPULMONARY INTERACTIONS
Restrictive Physiology
The Fontan circulation
Pulmonary blood flow in the TCPA:
Redington et al. Br Heart J 1990
CARDIOPULMONARY INTERACTIONS
Effect of ventilation-MRI
CARDIOPULMONARY INTERACTIONS
PEEP- Fontan
IVC
Arterial PO 2
Cardiac Index
5
4
200
Inspiration
3
PaO2
torr
CI
2
L/min/m
68%
FLOW (L/min)
2
SVC
100
1
0
0
3
6
*
*
9
12
0
0
PEEP cm H20
32%
Lars Sondegard
*
*
*
*
3
6
9
12
PEEP cm H20
Williams et al. JTCVS 1984
CARDIOPULMONARY INTERACTIONS
CARDIOPULMONARY INTERACTIONS
Negative pressure ventilation: TOF
IPPV Vs NPV
Transesophageal echo: TCPC
Shekerdemian et al. JACC 1999; 33(2): 549-555
Negative pressure ventilation: Fontan
CARDIOPULMONARY INTERACTIONS
High frequency oscillation
mean airway pressure
Total increase in Cardiac Output = 54%
P<0.001
6 children, unchanged MAP
9
4
cardiac index
CARDIOPULMONARY INTERACTIONS
6
3
IPPV
IPPV
15 mins
P = ns
2
HFOV
IPPV
HFOV
45 mins NPV
Bohn and Shekerdemian 1996
Shekerdemian et al. Circulation 1997; 96: 3834-42
CARDIOPULMONARY INTERACTIONS
CARDIOPULMONARY INTERACTIONS
Positive pressure ventilation
APRV
General management
Maintain SR, adequate RA
pressureMAP compatible
Lowest
Lowest total pulmonary
maintained
resistance
with
ventilation/alveolar
recruitment
-Ventilate around FRC
-Short insp time, short plateau,
low/no added peep
Constant airway
pressure
Intermittent timecycled pressure release
Allows spontaneous
respiration without
pressure support
Walsh et al. Critical Care Medicine Dec 2011
CARDIOPULMONARY INTERACTIONS
CARDIOPULMONARY INTERACTIONS
Airway pressure release ventilation
APRV: Spontaneous ventilation
20 patients (postop ToF, BCPS)
Respiratory mass spectrometry/Fick
Synchronised pressure controlled
Airway Pressure
mmHg
P=.09
12.3+2.6
11.3+2.5
Airway pressure released
L/mim/m2
Pulmonary blood flow
P<.02
2.9+1.5
2.5+1.5
ml/mim/m2
Oxygen delivery
CARDIOPULMONARY INTERACTIONS
Conclusions
RV function very dependent on
afterload
Modifiable via R-L interactions
Important cardiopulmonary
interactions driven by mean airway
pressure
APRV may be useful for some
patients during weaning
P<.03
528+208
620+285