fetal and neonatal hemodynamics: a focus on … · parasternal short axis suprasternal parasternal...
TRANSCRIPT
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FETAL AND NEONATAL HEMODYNAMICS:
A FOCUS ON ECHOCARDIOGRAPHIC ASSESSMENT
Pulmonary circulation***
Laurent Storme, CHRU de Lille, FRANCE
1
Université de Lille
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Outline
1. Why to assess pulmonary circulation ?;• Severe respiratory failure• Mechanism of shock
2. How to assess pulmonary circulation ?• Clinical examination;• Chest X-ray• Echocardiography
3. Particularities in Congenital DiaphragmaticHernia
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Respiratory failure
With severe hypoxemia
Hypoxemia
= R-L shunt
= « venous admixture »
100%60%
PaO2(mmHg)
45
Shunt=0 %
Shunt=20%
55
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Hypoxemia
Parenchymal diseaseIntrapulmonary shunt
PPHNExtrapulmonary shunt
LA
LV
RA
RV
PA
AlveoliAlveoli
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Principles of management
« Alveolar recruitment »
• Surfactant No surfactant
• mean airway pressure mean airway pressure
• Permissive hypercapnia Normalize PaCO2• Worsens with fluid/catecholamines Improves with fluid/Catecholamine
• Low NOi High NOi
« Vascular recruitment »
LA
LV
R
A
RV
PAPV
LA
LV
R
A
RV
PAPV
AlveoliAlveoli
Crit Care Med. 2007;35:1741-8
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PVR
Right
heart
Ductus arteriosus
Systemic
blood flow
Left
heart
PA Aorta
pulmonary flow
Obstructive shock
http://www.rivendell-peds.com/lungs.jpghttp://www.rivendell-peds.com/lungs.jpg
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Outline
1. Why to assess pulmonary circulation ?;• Mechanism of severe respiratory failure• Mechanism of shock
2. How to assess pulmonary circulation ?• Clinical examination;• Chest X-ray• Echocardiography
3. Particularities in Congenital DiaphragmaticHernia
-
LA
LV
RA
RV
PA
AlveoliAlveoli
• Anamnesis : No antenatal steroids PROM
• GA : Premature Full-term
• Etiology : HMD Infection, CDH
• O2 need : Stable Highly fluctuating
Pre- Post-ductal
SpO2 gradient
Clinical
Assessment
Of respiratory
failure
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LA
LV
RA
RV
PA
AlveoliAlveoli
Intrapulmonary shunting Extrapulmonary shunting
X-ray
Assessment
Of respiratory
failure
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FO
DA
LV outflowSkinner JR et al, Arch Dis Child 1999; 80: F81-7
LPA velocitiesWalther FJ et al, Pediatrics 1992; 90: 899-904 Rozé et al, Lancet 1994;344: 303-5Gournay Vet al. Acta Paediatr 1998; 87:419-23
Superior vena cava flow
RV outflow
Echocardiographic assessmentof hemodynamics : flow and velocities
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FO
DA DA shunting
Inferior vena
cava diameter
Tricuspid regurgitation
Echocardiographic assessmentof hemodynamics : pressures
FO shunting
Pulmonary regurgitation
Septum position
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FO
DA
• Tricuspid annular plane systolic excursion (TAPSE)
• Peak systolic tricuspidannular velocity
Echocardiographic assessmentof hemodynamics : function
• RV-myocardial performance index (Tei)
Septum position
• Speckle tracking
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But is it really useful ?
But adverse effects of stress on PVR !
0.4
0.6
0.8
1.0
1.2
-20 0 20 40 60 80 100 120 140
Time (min)
PV
R(m
mH
g/m
L/m
in)
suf+formol (n=6) formol (n=8)
Stress
Stress
V Houfflin et al, Am J Physiol, 2005
PVR
Stress
Stress + analgesia
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Echocardiographic assessment : in 3 views !
Parasternal short axis Parasternal long axis Suprasternal
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from 0.25 to 0.35 m.s
Artère
Pulmonaire
Gauche
Para-mediastinal
short axis view
To assess
the pulmonary
circulation
PA
DA
LPA
Ao
Rozé, Lancet 1994
Gournay, Acta Paediatr 1998
Mean velocities
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PA
DA
LPA
Ao
Para-mediastinal
Short axis view
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To estimate Aortic blood flow
Suprasternal view
DA
LVO
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0.25 to 0.35 m.s
0.25 to 0.35 m.s
Mean Ao Velocity
Rozé, Lancet 1994
Gournay, Acta Paediatr 1998
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EDD LV :
14 to 18 mm
At term
LA/Ao :
1 0.2
To evaluate volemia
Para-mediastinal
Long axis view
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SF LV = (EDD – ESD)x100/EDD = 30 to 40 %
To evaluate contractility
Para-sternal long axis view/TM
ESD EDD
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Anaïs / Meconial aspiration syndrome
• Severe respiratory failure:
– Intubated / ventilated : P 24/4 cmH2O, RR=60 c/min,
– FiO2 = 60%,
– Post-ductal SpO2 = 88%, preductal SpO2= 87%,
– PaCO2=55 mmHg
– Art P = 55/35 (42); HR= 155c/min
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Mean Velocity in Left PA
= 0.34 m.s
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Hypoxemia
Parenchymal diseaseIntrapulmonary shunt
Alveoli
PPHNExtrapulmonary shunt
LA
LV
RA
RV
PA
Alveoli
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Mainly intrapulmonary shunting
« Alveolar recrutment »
Alvéoli
PAO2PAO2
shunting
• Surfactant
• Mean Pressure
• hypoxic vasocontriction
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At H6 :
• Surfactant;
• HFO :
• Mean Pressure = 18 cmH2O
• Peak to peak = 95 cmH2O
• Improved : FiO2 = 30 %,
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At H24 :
• FiO2 = 100%;
• SpO2 pré = 84%, SpO2 post = 80%
• HFO : Mean P = 22; P to P = 110
• pH = 7.26, PCO2 = 54 mmHg
• Blue/grey: CRT >>> 3s
• Art P = 35/28 (30) mmHg, HR= 160
• Lactate = 580 mg/l
• Diurèse = 0
• Unstable +++
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Mean Velocity in Ao = O.21 m.s
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Mean Velocity in Right PA = 0.15 m.s
Parasternal short axis view
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Velocities in ductus arteriosus
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FO shunting
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RA
RV
LA
LV
DA
Obstructive shock
2 possible mechanisms:
1. LAP : Q pulm
2. RAP : RV failure
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PVR
Right
heart
Ductus arteriosus
Systemic
blood flow
Left
heart
PA Aorta
pulmonary flow
Obstructive shock
http://www.rivendell-peds.com/lungs.jpghttp://www.rivendell-peds.com/lungs.jpg
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Mean Velocity in Ao = 0.35 m.s
Management:
• iNO = 20 ppm
• Prostaglandin E1
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Mean velocity in Left PA = 0.36 m.s
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Outline
1. Why to assess pulmonary circulation ?;• Severe respiratory failure• Shock
2. How to assess pulmonary circulation ?• Clinical examination;• Chest X-ray• Echocardiography
3. Particularities in Congenital DiaphragmaticHernia
-
Ultrasound Obstet Gynecol 2010;35,310
Deprest J, Ultrasound Obstet Gynecol 2010;36,452
LV
en
d-d
iast
oli
c v
olu
mePrénatal Postnatal
CDH
Hypoplasia of
the left heart
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Pulmonary Hypertension
PAP = (Qp x PVR) + LAP
Flow
Resistance
Left
Atrial
Pressure
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PPHN
PAP =
(Qp x PVR)
+ LAP
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PVR
Right
heart
R Ductus Arteriosus
SVR
Systemic flow
Left
heart
Systemic flow = Qpulm + DA flow
+
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Violette, full-term, at 12Hrs:
• FiO2=30%, P 22/4 cmH2O, RR=50
• SpO2 pré=92%, postductal=65%
• HR = 122 / min, TcPCO2=58 mmHg
• AoP=55/33 (40) mmHg, CRT
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Pulmonary artery pressure = Aortic pressure
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Failure of circulatory adaptation :
Persistent Pulmonary Hypertension of the Newborn (PPHN)
Pre- and Post-ductal SpO2 gradient
O2 Delivery =
1.3 x AoFlow x Hb x SpO2
FiO2 should target PRE-DUCTAL SpO2 85-95%
DA
RA
RVLV
PA
RV
RALV
LAAP
Ao
Hypoxemia, but no hypoxia !
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Mean blood flow velocities
in Left Pulmonary Artery
= 0.25 m.s
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Inhaled NO ??? :
• Recommanded in PPHN (↓ ECMO) ;
• Few CDH cases respond to iNO;
• No evidence that iNO improves outcome (death or ECMO);
• ↑ need for ECMO in CDH !
iNO cannot be recommanded in CDH infants with PPHN as long as preductal SpO2 is
adequate
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Lung overinflation
To prevent iatrogenic issues
0.4
0.6
0.8
1.0
1.2
-20 0 20 40 60 80 100 120 140
Time (min)
PV
R(m
mH
g/m
L/m
in)
suf+formol (n=6) formol (n=8)
Stress
Stress
Houfflin. Am J Physiol, 2005Houfflin. Anesth Analg, 2007
PVR
PVR
Dopamine
Jaillard S, Am J Physiol. 2001
Bouissou A, J Pediatr 2008
Painful stimuli
Painful stimuli + analgesiaBenzodiazepine
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Take home message:
Appropriate management in severe respiratory failure:• To assess the mechanisms of the respiratory failure (intra or extrapulmonary shunting ?);• To determine the mechanism of the Pulmonary Hypertension:
– High pulmonary vascular resistance ?– Post-capillary PH (Hypoplasia of the Left Heart in CDH) ?– High pulmonary blood flow ?
• To adapt treatment :– Pulmonary vasodilator when high PVR-induced low pulmonary blood
flow ;– Re-open the DA in suprasystemic PH;– « Better is the ennemy of good », in postcapillary PH;
• To prevent iatrogenic issues:• Overdistension of the lung• Deep sedation using midazolam or propofol