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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
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
Respiratory failure
With severe hypoxemia
Hypoxemia
= R-L shunt
= « venous admixture »
100%60%
PaO2(mmHg)
45
Shunt=0 %
Shunt=20%
55
Hypoxemia
Parenchymal diseaseIntrapulmonary shunt
PPHNExtrapulmonary shunt
LA
LV
RA
RV
PA
AlveoliAlveoli
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
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
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
LA
LV
RA
RV
PA
AlveoliAlveoli
Intrapulmonary shunting Extrapulmonary shunting
X-ray
Assessment
Of respiratory
failure
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
FO
DA DA shunting
Inferior vena
cava diameter
Tricuspid regurgitation
Echocardiographic assessmentof hemodynamics : pressures
FO shunting
Pulmonary regurgitation
Septum position
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
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
Echocardiographic assessment : in 3 views !
Parasternal short axis Parasternal long axis Suprasternal
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
PA
DA
LPA
Ao
Para-mediastinal
Short axis view
To estimate Aortic blood flow
Suprasternal view
DA
LVO
0.25 to 0.35 m.s
0.25 to 0.35 m.s
Mean Ao Velocity
Rozé, Lancet 1994
Gournay, Acta Paediatr 1998
EDD LV :
14 to 18 mm
At term
LA/Ao :
1 0.2
To evaluate volemia
Para-mediastinal
Long axis view
SF LV = (EDD – ESD)x100/EDD = 30 to 40 %
To evaluate contractility
Para-sternal long axis view/TM
ESD EDD
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
Mean Velocity in Left PA
= 0.34 m.s
Hypoxemia
Parenchymal diseaseIntrapulmonary shunt
Alveoli
PPHNExtrapulmonary shunt
LA
LV
RA
RV
PA
Alveoli
Mainly intrapulmonary shunting
« Alveolar recrutment »
Alvéoli
PAO2PAO2
shunting
• Surfactant
• Mean Pressure
• hypoxic vasocontriction
At H6 :
• Surfactant;
• HFO :
• Mean Pressure = 18 cmH2O
• Peak to peak = 95 cmH2O
• Improved : FiO2 = 30 %,
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 +++
Mean Velocity in Ao = O.21 m.s
Mean Velocity in Right PA = 0.15 m.s
Parasternal short axis view
Velocities in ductus arteriosus
FO shunting
RA
RV
LA
LV
DA
Obstructive shock
2 possible mechanisms:
1. LAP : Q pulm
2. RAP : RV failure
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
Mean Velocity in Ao = 0.35 m.s
Management:
• iNO = 20 ppm
• Prostaglandin E1
Mean velocity in Left PA = 0.36 m.s
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
Pulmonary Hypertension
PAP = (Qp x PVR) + LAP
Flow
Resistance
Left
Atrial
Pressure
PPHN
PAP =
(Qp x PVR)
+ LAP
PVR
Right
heart
R Ductus Arteriosus
SVR
Systemic flow
Left
heart
Systemic flow = Qpulm + DA flow
+
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
Pulmonary artery pressure = Aortic pressure
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 !
Mean blood flow velocities
in Left Pulmonary Artery
= 0.25 m.s
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
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
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