cardiovascular system – cardiovascular changes at birth · cardiovascular system –...

Cardiovascular System – Cardiovascular changes at birth

Dr Graeme Polglase

the Ritchie Centre

Transition at Birth

Contents

The cardiopulmonary circulatory transition. Fetal and adult physiology Mechanisms driving the transition

Stabilisation of the cardiopulmonary circulatory transition.

New insights into the benefit of delayed cord clamping.

Adult vs. Fetal circulation

Fetus: – Umbilical flow supports

LVO and RVO. – Ventricles pump in

parallel due to:

– foramen ovale – ductus arteriosus

Driven by: – umbilical circulation

Newborn/Adult:

– Ventricles pump in series

PUMP 1. Blood flows from high pressure to low pressure

P1

P2 P3

If P1 and P2 > P3 Blood will flow down P3.

Pressure

If P1 > P2 & P3 (P2 = P3) Blood will flow equally In both directions. = >

PUMP

P1

P2 P3

2. Blood flows along the path of least resistance.

R2

If R1 = R2 Blood will flow equally through both

Resistance

If R1 > R2 Blood will flow through R2 R1 = >

Right Ventricle

Fetal Circulation

Lung

Pulmonary Circulation

Systemic Circulation (Placenta)

Ductus Arteriosus

Pulmonary Circulation: High Pressure High Resistance Low Blood Flow

Systemic Circulation: Lower Pressure Low Resistance

PPA > PSA

PVR > SVR Ductus Arteriosus: Right to Left Flow

45-50 mmHg 40-45 mmHg

Pulmonary circulation

Vasoconstricted during fetal life – high resistance & low blood flow – pulmonary pressure > systemic pressure – right-to-left shunt through the ductus

arteriosus.

Causes of vasoconstriction – not known – High degree of fetal lung expansion. – Low PO2

– Release of circulating vasoconstrictors.

Right Ventricle

Newborn Circulation

Pulmonary Circulation

Systemic Circulation

Ductus Arteriosus

Pulmonary Circulation: Low Pressure Low Resistance High Blood Flow

Systemic Circulation: High Pressure Higher Resistance PPA < PSA

PVR < SVR Ductus Arteriosus: Left to Right Flow

Cardio-Pulmonary Transition at Birth

Newborn 100% of RVO enters the lung PBF is high, PVR is low Systemic arterial pressure > pulmonary arterial pressure DA flow is left to right

Need to 1) Decrease pulmonary vascular resistance 2) Reverse pulmonary-systemic pressure gradient

1) Decrease in pulmonary vascular resistance at birth

Overall mechanism unknown – ↑ blood PO2

– release of vasodilators (?) – An effect of ventilation (?) – Reduction in lung volume caused by lung

aeration

Aeration of the lung is the principal component!

Pulmonary blood flow changes at birth

2 mins

Start Ventilation Clamp cord Deliver

+ve

-ve

Instability

FETUS NEWBORN


Need to 1) Decrease pulmonary vascular resistance Aerating the lung

2) Reverse pulmonary-systemic pressure gradient

Cardiovascular changes at birth

Reversing the pulmonary-systemic pressure gradient Clamp umbilical cord

– lose 1/3 of fetal blood volume • Umbilical cord “milking” (or leaving the cord open)

– lose 50% of venous return / right ventricular output. – ↑ Systemic blood pressure

Driven by removal of the placental circulation

Before Cord Occlusion

After Cord Occlusion

Start ventilation

Cardiovascular changes at birth

Venous return from umbilical circ ↓ → ↓ right atrial filling ↓ right atrial pressure (RAP)

+ aeration of the lung

Pulmonary vascular resistance ↓ → ↑pulmonary blood flow. ↓ pulmonary arterial pressure ↑ left atrial filling → ↑ left atrial pressure

Systemic arterial pressure > Pulmonary arterial pressure (left to right ductus arteriosus flow) LAP > RAP → reversal of flow through and closure of foramen ovale (FO)

All happens within the first minutes of life.


Need to 1) Decrease pulmonary vascular resistance Aerating the lung

2) Reverse pulmonary-systemic pressure gradient

Remove the placental circulation

Body

FO

Placenta

Brain

Right Heart

Lungs (High PVR)

50 % of CVO

50 % of CVO

Left Heart

The cardiopulmonary transition

DA

Before Cord Occlusion

After Cord Occlusion

Start ventilation

Umbilical cord occlusion

ventilation Lungs (Low PVR)

PPA > PSA PPA < PSA

Stabilises Left and Right Ventricular Output at Birth

Contents

The cardiopulmonary circulatory transition. Fetal and adult physiology Mechanisms driving the transition

Stabilisation of the cardiopulmonary circulatory transition.

New insights into the benefit of delayed cord clamping.

A Role for Neuroprotection?

~50 mmHg 90-150 mmHg

“developmental immaturity can render the preterm neonate particularly susceptible to cerebral hemodynamic consequences in response to systemic disturbances”

Impaired Cerebral Autoregulation

Circulation Stabilisation – Delayed Cord Clamping

Does the timing of ventilation onset relative to umbilical cord clamping improve the stability of the circulatory transition at birth in a baby which is apnoeic?

Flow probes: • Left pulmonary artery • Ductus arteriosus • Carotid artery

Catheters: • Main pulmonary artery • Main Carotid Artery • Jugular Vein

Surgical Methods

Experimental timeline

(Clamp 1st Vent 2nd)

-1h 0 5 10 20 30 min

(Vent 1st Clamp 2nd)

-1h 0 5 10 20 30 min

Cardiovascular effects of cord clamping prior to ventilation.

Fetus

the RITCHIE CENTRE

Placenta

Right Heart

Left Heart

Upper body

Lower body

Ductus arteriosus

Pre-ductal arteries

Foramen Ovale

X X

Lungs

Low resistance 50% of CO

What are the cardiovascular consequences of cord clamping prior to ventilation?

20

70

20

70

-200

600

-400

900

0

200

CA

P

(mm

Hg)

P

AP

(m

mH

g)

PB

F (m

L/m

in)

DA

BF

(mL/

min

) C

AB

F (m

L/m

in)

Cord clamp

Changes over the first 10 heart beats

Placenta

Right Heart

Left Heart

Upper body

Lungs

Lower body

Ductus arteriosus

Foramen Ovale

X X

Cord clamp

Lung

Left Ventricular Output Critically Dependent Upon Increasing Pulmonary Blood flow

Effect of cord clamping followed by ventilation

Clamp Vent Clamp Vent

Placenta

Right Heart

Left Heart

Upper body

Lungs

Lower body

Ductus arteriosus

Foramen Ovale

X X

Effect of cord clamping followed by ventilation

Clamp Vent Clamp Vent

Delaying Cord Clamping until Ventilation Initiated

Lungs aerate

Placenta

Right Heart

Left Heart

Upper body

Lungs

Lower body

Ductus arteriosus

Foramen Ovale

X X 50% Venous Return

the RITCHIE CENTRE

20

70

20

70

-200

600

-400

900

0

200

CA

P

(mm

Hg)

P

AP

(m

mH

g)

PB

F (m

L/m

in)

DA

BF

(mL/

min

) C

AB

F (m

L/m

in)

Unventilated (Clamp 1st) Ventilated (Vent 1st)

Cardiovascular consequences of ventilating before cord clamping

Cord clamp Cord clamp

Changes over the first 10 heart beats

Clamp First Ventilate First

Ventilation before cord clamping stabilises the cardiovascular transition at birth

Clamp First Ventilate First

Improves Stability!

Benefits of delayed cord clamping until ventilation onset

• Decrease PVR and hence increase PBF before the cord is clamped

• PBF can immediately replace umbilical venous return as the primary source of preload for the LV – Stabilises LV output after birth – Potentially reduces risk of IVH

Acknowledgements

The Ritchie Centre Stuart Hooper Sasmira Bhatt Euan Wallace Kelly Crossley Beth Allison Valerie Zahra and the entire lab

Royal North Shore Hospital Martin Kluckow

King Edward Memorial Hospital Andrew Gill

Leiden University Medical Centre Arjan te Pas

Beyond Retirement Colin Morley

Spark of Life Neonatal Satellite

2013

The magic minutes after birth – making the most of them Transition from placenta to air breathing

Prof Stuart Hooper

Using oxygen wisely in the delivery room

Dr Jennifer Dawson

Transitional Circulation Dr Graeme Polglase Sustained inflations at birth Prof Stuart Hooper Monitoring in the delivery room Prof Peter Davis

Role of a sustained inflation

at birth

Stuart Hooper

the RITCHIE CENTRE

Should a liquid-filled lung be ventilated in the same way as an air-filled lung? Will they behave the same?

Inspiration

P

+P

Inflation Pressures drives airway liquid movement

the RITCHIE CENTRE

Inspiration

P

Pressures generated by Inspiration drives airway liquid movement

the RITCHIE CENTRE

+P

Inspiration

+P

P


the RITCHIE CENTRE

P P P


the RITCHIE CENTRE

Inspiration

Partial airway liquid retention non-uniform ventilation

P = pressure

P

P

P P

P P

P

Should a liquid-filled lung be ventilated in the same way as an air-filled lung? Will they behave the same?

Ventilation: the basics

O2 CO2

Inspiration

Exhalation

When the lung is liquid-filled: Inspiration - needed for airway liquid clearance Expiration - superfluous as no gas exchange

the RITCHIE CENTRE

Uniform Lung aeration

Sustained Inflations What are the Unknowns??

How long should the sustained inflation be?

What Inflation pressure?

Physics of lung aeration

viscosity x length tube (radius tube)4

R1

Smaller very preterm infants:

Smaller airways + lower surface area = Resistance

R2 determine by epithelial barrier properties and surface area

R1 R2

RT = R1 + R2

R1 = resistance to moving liquid through a tube R2 = resistance to moving liquid across alveolar wall

2010 ILCOR Guidelines

Recommend inflation pressures of:

30 cmH2O in term infants and

20 to 25 cm H2O in preterm infants “occasionally higher pressures are required”.

Duration & Inflation pressure for a SI

0

15

30

45

0

10

20

Lung

air

volu

me

(mL/

kg)

Airw

ay p

resu

re

(cm

H2O

)

RT = P x T/ΔV

Time

ΔV

Effect of age on SI starting pressure

P1 P2 >>

Effect of age SI duration and airway resistance

P1 P2 >>

Sustained Inflations: where are we?

Inflation Pressure and duration will differ between infants: Airway size Maturity of the distal airways The volume of airway liquid present at birth

Solution?? Target an inflation volume of 20mL/kg

American NRP text book

Cardiopulmonary resuscitation

What do the guidelines say?

HR <60bpm (apneic, non-responsive infants) Start chest compressions IV epinephrine

Respiratory support ILCOR - No consensus

“initiation of intermittent positive-pressure ventilation at birth can be accomplished with either shorter or longer inspiratory times”

European - 5x 3 sec inflations

Cardiopulmonary resuscitation

“Establishing pulmonary ventilation is the key”

How???

Conventional 60 breaths/min 5x 3 sec inflations ????? 30 sec sustained inflation

Protocol

Deliver & Clamp cord

Start resuscitation BP = 20-25 mmHg

Finish 30 min after Resuscitation start

Groups 1. Conventional 60 breaths/min 2. 5x 3 sec inflations 3. 30 sec sustained inflation

Outcomes 1. Restoration of HR >120 bpm 2. Restoration of BP > 40 mmHg 3. Respiratory mechanics

HR Changes

Resuscitation start

Restoring cardiac function

Why is a SI so effective?

Better at aerating the lung To increase O2 uptake

To increase PBF and increase preload

But is this a good thing?? Could the higher BP cause brain

haemorrhage

Blood brain barrier

Extravasation of serum indicates disruption to the blood brain barrier.

the RITCHIE CENTRE

No extravasation Extravasation (Immunoreactive blood vessel)

Sheep serum extravasation- blood brain barrier disruption

the RITCHIE CENTRE

Blood brain barrier disruption

the RITCHIE CENTRE

Data presented as median (IQR)

Total blood vessel profile scores

There were more animals showing BBB disruption after a 30 sec SI

a

b

ab

Summary

Sustained inflation is fantastic at increasing HR in severely asphyxic newborns

But!! the return in circulation may be too quick and should be tempered to prevent brain haemorrhage


2013


Prof Stuart Hooper


Dr Jennifer Dawson


Monitoring of the newborn infant in delivery room

Peter Davis Melbourne

Australian Resuscitation Council Neonatal Satellite Meeting

Evaluate respirations, heart rate and colour

ILCOR 2005

Assessment in the DR

• Colour • Heart rate • Chest rise • (tone and reflex irritability)

Can we use clinical assessment of colour?

• 3-5 minute clips from 20 videos of varying gestation requiring varying degrees of resuscitation (including none)

• 27 medical and nursing observers noted the time at which the infant turned pink

• Corresponding oxygen saturation from a masked oximeter noted

How well do 27 observers agree about colour?

How well do 27 observers agree about colour?

• Median saturation at which babies thought to become pink was 69

• Range extended from 10 to 100!

Colour and oxygen • Improvement in colour may take several minutes

to achieve, even in uncompromised babies. Exposure of the newly born to hyperoxia is detrimental to many organs at cellular and functional level.

• Therefore, colour has been removed as an indicator of oxygenation or resuscitation efficacy

ILCOR guidelines

Pediatrics, 2010, 126 (5), p. e 1321.

Can we use the colour of an infant’s tongue?

• The Giraffe study

Infant characteristics Characteristics: Study group:

n= 68

Gestational age, mean (SD), week 38 (2)

Birth weight, mean (SD), g 3214 (545)

Apgar score at 1 min, median (IQR) 9 (8-9)

Apgar score at 5 min, median (IQR) 9 (9-9)

Type of anaesthesia, n (%)

Spinal/epidural 66 (97)

General anaesthesia 2 (3)

Time to first data, median (IQR), sec 76 (67-91)

Assessor characteristics

Characteristics: n (%): Midwives 38 (84)

Paediatricians 7 (16)

≤1 year of experience 14 (31)

>1 year of experience 31 (69)

Results

• When the colour is pink, the baby has a saturation >70% and probably does not need supplemental oxygen

0.0

00.2

50.5

00.7

51.0

0S

en

sitiv

ity

0.00 0.25 0.50 0.75 1.001 - Specificity

Area under ROC curve = 0.8642

Measurement of Heart Rate (HR) in the delivery room

• Guidelines recommend auscultation or umbilical cord palpation (count for 6 seconds and multiply by 10)

• HR is an (the most?) important sign in determining need for and response to resuscitation

• How precise and accurate are clinical measurements?

Assessment of heart rate: Auscultation & palpation v ECG

-----------------------------------------------

Kamlin CO, O'Donnell CP, Everest NJ, Davis PG, Morley CJ. Resuscitation. 2006

Assessment of heart rate • Auscultation of the heart rate is more accurate than palpation

of the cord. However, both are relatively insensitive.

• Auscultation of the heart rate should remain the primary means of assessing heart rate. There is a high likelihood of underestimating the heart rate with palpation of the umbilical pulse, but this is preferable to other palpation locations.

ILCOR guidelines

Pediatrics, 2010, 126 (5), p. e 1321.

How should we judge ventilation?

• Chest movement? • Manometer?

ILCOR guidelines: Initial breaths

• Avoid excessive chest wall movement during ventilation of preterm infants

• Monitoring of inflation pressures may help provide consistent inflations and avoid unnecessarily high pressures

Pediatrics, 2010;126(5):e1323.

Displayed PIP vs Expired tidal volume

Schmölzer et al, Arch Dis Child Fetal Neonatal Ed. 2010;95(6):F393-7.

Peak inflation pressure in cm H2O

Expi

red

tidal

vol

ume

in m

l/kg

Chest wall movement?

• Infants < 32 weeks gestation who received face mask PPV immediately after birth

• Estimate tidal volume (quantitative and qualitative) – head view – side view – experienced and inexperienced operators

• Hot-wire anemometer flow sensor to measure gas flow and tidal volume

Poulton et al, Resuscitation 2011;82:175-179.

Tidal volume 0

10

20

30

4 8

10 13 2 9 16 14 5 6 11 18 19 20 15 17 7 1 3 4 8 12

expi

red

tidal

vol

ume

(VTe

) in

mL/

kg fo

r eac

h op

erat

or

measured VTe estimated VTe

Tidal volume 0

1020

304

8ex

pire

d tid

al v

olum

e (V

Te) i

n m

L/kg

for e

ach

oper

ator

measured VTe estimated VTe

1

3 4

12

18 19 20

10

13

8 9

2

16

5 6

11

17

15

7

14

8

Chest movement vs Expired tidal volume

0

2

4

6

8

10

12

14

Not at all Too low Appropriate Too much Not sure

Expi

red

Tida

l Vol

ume

(ml/

kg)

Clinical signs of effective ventilation are imperfect

• Displayed PIP is a poor surrogate for tidal volume delivered

• Chest rise is an inaccurate, unreliable measure of adequacy of ventilation

Why might this be important?

Too much ventilation

• Björklund (Pediatric Research 1997) – 5 pairs of 127-128 day lambs (~28 weeks’)

• Six large manual inflations – reduced compliance – worse gas exchange – widespread lung injury

Excessive bagging

Standard resuscitation

What can help us?

• Pulse oximetry – How to apply – How accurate? – Limitations

• Respiratory function monitoring – An introduction

PO Sensor

Pulse Oximeter

Patient Cable

Conclusion: Apply the sensor to the right hand and then to the patient cable

Feasibility of oximetry in the DR

Using optimal technique: • 90% of infants have oximetry data in < 92 sec • preterm infants are easier to monitor than term

O’Donnell, Kamlin, Davis and Morley, J Pediatr 2005;147:698-9

How accurate is PO measurement of heart rate?

Pulse oximetry vs ECG Heart Rate

Ability of PO to detect HR <100 •Sensitivity 89% •Specificity 99% •PPV 83% •NPV 99%

40 60 80 100 120 140 160 180 200

Heart rate from ECG

40

60

80

100

120

140

160

180

200

Hea

rt ra

te fr

om M

asim

o Pu

lse

Oxi

met

er

AAAAAAAA A

AAA

AAAA

AAA

AAAAAAAAAAAAAAA

AAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAA

AA AAAAAAA

AAAA

AAAA

AAA

AA

A

AAAAA

A A A

AAA

AAA

A

A

AA A A

A

AAAAA AAAA

AAAA A A

AAAA AAA AAA

A AAAA AAAAAAAAAAAA AAAA AAAAAAA AAAAAA

AAA

AAA

AA AA

A A A AAA

A A

A AAA

AA

A

AA

A A AA A AA

A

A AAA

AAAA

A

AAAA AAA

AAAA

AAAAA A

A

A

AAAAA

A

AAA

A

AAA AA

AA

AA A AAA

AAA

AAA AA

AA

A AAA AAAAA AA

A

A

A

AA

AAA

AA

A AA AA

AA

AAAAA AAAAAAA AAAAAA

A AAAA

AAAAA A

A AAAA AAAAAAAAAA

A

A AAAAAAAAAA

AAAAAAAA

AA AAAAAAA AAA AAAAAAA AA AAAAAAAAAA AA

A

AAAAAAAAAAAAAAAAAAAAA

AAAAAAAA

AAAAAAA

A AAAAAAAAAAAAAAAAAAAA

A AAA

AAAAAA

AAAAA AAAAAAAAAAAAAAA

AAAAAA A

AAAAA AAA AAAAAAA

A AAAAAAAAAA AAAAA

AA AAAAAA AAAAAAAAAAAAAAAAAAA AAA

AA AA A AAAAAA AAAA AAAAAAAAAAA AAAAA A AAA AAAA AAAAAAAAAAAAAAAAAAAAAA AAAAAAAAA A AAA AAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAA

AAA AAAAAAAAAAA

AAAA

AAAAAA AAA

AAAAAAAAAAAAAAAAAAAA

A

A

AAA

AAAAA

A

AAAAAAAAAAAAA

AAAAAAA

AA

AAAAAAAA

AAAAA

AAAAA

AAAA

A

A

A

AAA

A

A

AA

AAA

AAAAAAA A

A

AAA AA

A AAA

A A

AA

AAA

AAAAAAA

A

A

AAAAA

AA

AAA

AA

A

AAAAAA

A

AA

A

AA AAA

AA

A

A

AAAAAA

AA

AA

A A

A AAAAA

A

AAAAAAAAAAA

AAAAA A

AAA

A

AAA

AA

AAA

AA

AAAA A

AAAAAAAAA

A

A

A

A

AA

A

A

A

AA

AAA AAA AAAA

A

AA

AAAA

AA

AAA

AA A A

AA

AAAAA AA AAA

A

A

AAAAA

A A

A AAAA

AAA

AA

AA

AAAA

AAA

A AA

AA

AAA

AAA

AA

AAAA

A

AA A

A

AA

AAAAA

A

AAA

AA A

A

AAA

AA

A

A

A A

AAA

A

AAAA

AA

AAA

AA A

AAA

AA AAAAAA

AAAAAAAA

AAAAAA

AAA

AA

AAAA

A A

AA

AAA

AAAAA

A A

AA

AAA

A

A

AA

A

AAA

AA

AAAAA

AA

AAAA

AA

A

AAAAAA

AAAAAAAA AAAA

AAA

A

AA

AA

AAAAAAAAAAAAAAAAA

AAAAAAAAAAAA

AAAAAA

AAAAAAAAAA AA

AAAAAAAAAA

AAAAAA

A A AAA AAAAAA

AAA

AA

A

AA A

AA

A

AAAAAA AAAA

AAAAAA

AAAA A AAAAA

AAAAA AAAA AAAA

AAAAAAAAAAA

A AAAAAA

AAAAAA

AAA

AAAAAAAA AA

AAA

AA AA

A

AAAAAA

A A AA AAAAA

AAAAAAAA AAAAAAA

AA

AAAA

AAAA

A

AAAAAAAAAAAAA

AAAA

AA

A

AA

AAAAAA

AAA

AAA A

AAAAAAAAAA

AAAAAAAAAAAAA

A

A

AAA

AAA

AAAAA

AA

A

AAA

AA A

AAAAA

AAAAAAA AAA

AAAAAA

AA

A

AA

AAA AA

AAAAAA

A

AAA

AA

AAAA A

A

AAAAA AAA AAAAA

AA

AAAA

AAAA

AAAA

AA

AAA

AAAAA

A

AA

A

A

AA

AAAA

A

AA

AAA A

AAAAA

AA

AAA

A

AAA

A

AAA

AAAAAAAAA

AA

A

AAAA

A

A AAAAAAAA

A

A

AAA AAAA

AAAAA

A

AAAA

A

AA

AA

A A AAAA

AA A A

AAA AA

AAAAAAAAAAA

AAAAAAAA

A A

AA

AAAAA

AAA

A

A AA

A

AA

AAAA A

A

AAA A

A

AAAAAAA

A

A

AAAA

AAA

AA

A

AAA AA

AA

AAAAAAA

AA

AA

A

AAAA

A AAA

AAA A AAAA A A

AAAA

AAAAA A A

AA

AA A

AAAAAAA AAAAAA

AAA

AAAAAAAA

A

A

AAAAAAAAAAAAA

A AA A A AAAAA AA

AAA AAAAAAA AAAA

AAAAAA

A

AAAAAA AAA

AAAA AAA

AAAAAA

AAAA AA A

AAA AAAA AAAAAAAAAAAAAAA

AAAAAAAAA

AAAAA

AAAAAA

A

AAA

AAAAAAAAA

AAA AAAA

AAAA

AAA

AAAAAAAAAAA

A

AAAAAAAA

AA AA

A

AAAAAAAA

AAAAAAAAAA

AA

AAA

AAAAA

A AAAAAA

A

AAA

AA

A A

AAA

A

AAAAAAA

AAA AAAA

AAAAAAAAA

AAAAAA AAA

A

AAAAA

AAA

AAAAAAAAA

AAAAAAAAAAA

AAAAAAAAAAAAA

AA A

AA

A

AAA

AA

A AAA

A

AA AA

AAAAAAAA

A

AAA

AAA A A

A AA

A

A

AA

AAAA

AA

A A AA A A

AAAAAA AA AA

AA

AAA AA AA

AA

A

AA

A

AAAAAAAA A

AAA

AAAAAA

A

A

AAA

A

A AAAAAAA AAAAAAAAA AAA

AAAAAA

A

AA

AAA

AA

A

AAAAA

A AA

AAAAA

A

AA

AAA

AA

AAAAA

AAA AAAAA A

A AAAAA A AAA

AAAA AAAAAAAAA

AAA

AA

AAAAA A A AAAAAAA

A

AAA

A

A A AAAAAA AAAAAAAAA AAAAA

A AAAAAAA AAAAAA

AAAAAAAAAAAA

AAAAAAAAAAA AA

AAA

AAAA

AAAAAAAAAA

AAAAAAAAAAAAAAA

AAAAAAAAAA

AAAAAAAAAAAA

AAAAA AAA

AAAAAAAAAAAAAAAAAAAAAAA

AA

AAAAAAAAAAAA AAAA

AAAAAAAA

AAAAAAAA AAAAAAAAAA

A AAAAAA

AAAAAAAAA AAAAA

A

AAAA A

A

A AA AAAAAA

A A AA

AAAAAAAA AAA

AA

AA

A AA

AAA

A

AAAAAAA AAAAAA

AAA A

A A AAA AA AAAA

AA

AAA

AAAAAA

AAAAAAAAAAAAAAAAAAA

AAA AAAAAAAAA

A

AA

AAAAAA AA

AAAAAAAAA AAAAAA AAA

A

AAA AA AAAA

AAAAAAA A AAAA AAAA

A AAAAAAA

AA

AA

AAAAAAA

AA

A

AAAA

AA

A AA

AAA

AAAAAAAAAAAA

AAAAAAAA

AA

AA

AAAAAAAAA

AAAAAAA

AAAA AAAAAAAA

AAAAAAAAAAAAAAAAA AA

A

AAA

AAAAA

AAAAAAAAA

AAAA

AA

AAAA

AA AA AAA

A

A A

AA

AAAAAAAAAAAA

A

AA

A

A

A A AA AA

AAAA A

A

AA AA

AAA

AAA

A AAAAAA AAA

AAAAAAAA

AAAAAAA

AAAAA AA

AAAAAAAA

AAAA AAA

AA

A

A AAA

AAAA A AAA AAAAAAAA

AA

AAA

AA

AA AAA

AAAAA A

AA

A

AA

A

A A AAA A A

AA

AA

AA

A

AAAAA

A

AAAAA

A

AAA

AA

A

AA

AAAAA

A AAA A

AAAAAAAAAAAAAA

AAA

A

A

A A

AAA

AAA

AAA

AA

AAAAAAA A A

AAAA

A AAAA

AAAAA

AAAAAA

AA A

AAAA

AAAA

AAA

AAA

A A AA

AAAAAA

AA

AAA

AAAAAAA

AAAAAAAAAA AA

AAAAA AAAAAAAAAA

AAA AAA

A AA

AAAA

AAAAAAAAAAAAA

AAAAA

AA

AAAAAA

AAAA

AAAAA AAAAA A AA AA

AA

AAAAAAAAAAA

A

A

AA

A

A

AA AAAAAAAA

AA AA

AAA

AA

AA

AAAA

A A

AA

AAAAA

AAA

AAAA

AAA

A

AAAAA

AAAA

AAA

AAAAA

AAAA

AAAAAAAAAAA

AAAA

AA A

AAAAAA A

AAAAA AAA

A

AAAAAAAAAAA

AAA A

AAA

AAAAA AAAAAAAAA

A

A A

AAA A A

AAAAAA AAA

A

AA

AAAAAAAAAAAAAA A

A AAAAAA

A

AA A

AAAA

AAAA

AA

AAAAAAAAA

AAAAAA

AA A A

A

AAA

A

A

A

A

AAA

AAAA A

A

A

AAA

A A

A

AA

AAAAAA A A AAA AAAA

A AAA

AAAAAA

A

AAAAAA AAA

AA A AA

AA

AAAAAAAA A

AA

AA

A

A

AAAA

A

AAA

A

A

A

AAA

A

AAAAA

AAA

AAA

AA

AAAAAAAAAAAAAAAAAAAA AAAAAAAA

AAAAAAAAA

AAA

A

AA AAAAAA AAAAA

AAA

AA A A

AAAAAAAAAAAAAAAAAAAA

A

AAAAAAAAAAAAAAAAA

AAAAAAAAAA AAAAAAAAAAA

AAAAAAAAAAA

AAAAA A

AAAA

AAAAA

A

AAA

AAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAA

AAA

AAA AAAAAA

AAAAAAAAAAAA

AA

A

AAAAAA A AAA AAAAAAAAAAAAAAAAAAAAAAAA

A AA

A AAA

AAAA

A

AA

AAAAAAAAAAAA

A

A A A

A

A

A

AAAA

A

A

AAAAAAAAAAA

AA

AA

AA A

AA

AAA

A

A

A A

AA A

A

AA

AA AAAAAA

A

A

A

AA

AAA

AAAAAA

AAAAAAAA AA AA

AAAAA

AAAAA AAAA

AAAA AA

AAAA

AA

AA AAAAAAAAA

AAAAA A AAAAAAAAAAAAAAA

A AAAAAA AAAAAAA AAAAAAAAAAAA

A

A

AAA

A A

A

A AAA

A

AAA

A

AA

AA

A

AAA

AA

A

A

A AA

AAA

AA

AA

A

A

AAAA

A

A

AAAA

A

AAA

A

A

A

AA

AA

AA

AA

A AAAA

AA AAAAA

AAAA

A AAA A

A AAAA

A AAAAAAA

AAA AA

A AA

AAAA

AAAAA

A

A

AAAAAAA A

AA AAAA

AAAAA A AA A

AAAAAAAAAAAAAAA

A AAA AAAAAAAAAA

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

AAAAAAAAAAAAA AAA AA

AA

AAAAAA AA AA

AAAAAAAAA AAA AAAAAAAAAA

AA AAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAA AAAA

AAAAAAAAA AA

AAAAAAAAAAAAAAAAAAAAA

AAAAAAA

AAA

AAAAA

A

A

AAA

AA

AA

AAA

AAA

A

AA A

AAA

AA

A A

A

A AAA AA

AA AAAAAA

AA

A AA

A

A

AAAAAAAAAAAAAAAA

AAA AAAA A

AAAAAAAAAAAAAA AAAA

AAAAAA AAAA

AAA

A

A

AA

A

AA

AAAAAA

AA

AAAAAAAAAAAAAA

A

A

A

AAAAAAAAAAAAAA

AAAAAA

AAA

A

A

AA

AA AA

A A AAAAAAAAAAA

A

A AAA

AAAA AAAAAAA

AAA AA A

AAA

A

A

AAAAAAA

AAAAAA

A

AAAAAAAAAAAA

AAAAA AA AAAA AAAA

AAAAAAA

A

AAAAA

AAAAAAAA

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

A AAAAAAAAAAAAAAAAAA

AAAAAA A

AAAA

AAAAAAAAAAA

AA AAAAAA

AAAAAA AAAA

AAAAA AAAAAAAAAA

AAAAAAAAAA

AAA

AA

AA AAAA A

A A

A

A A

A

A

A

A AA

AA

A

AAAAAAAAAAAAAAAAAA AAA

AAAAAAAAAAAAAAAAAAA

AAAAAAAAAAAAA

AAAAAAAAAAA

A

AA

A A

A

AAA

AAAAA

A

AAA

AAAAAAAAAAAA

A

AAA

AA

A

A

A

AA

AA

A AAA

AA

AA

A

AA

AAAA

AAA

A

A

AAA A

A

A

AAAA

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

AAAAAAA

AAAAAAAAAA

AAAAA

AAA AA

AAAAAAAAAA AAAA

AAA

AAAAAAAAAAAAAAAAA

AAAA

A

AAAAAAAAAAAAAAAAAAAAAAAAAAA

n=206 (4%) n=42 (1%)

n=4871 (94.5%) n=26 (0.5%)

Accuracy of pulse oximetry measurement of heart rate of newly born infants in the delivery room. Kamlin, Dawson, Singh, Morley, Donath, Davis. Journal of Pediatrics 2008;152(6):756-60.

10.1

-11.6

-100

-50

050

HR

from

EC

G m

inus

HR

from

Nel

lcor

PO

(bpm

)

50 100 150 200Average of HR from ECG and HR from Nellcor PO (bpm)

-0.8

Agreement between HR measurements

B A

Bland-Altman plots showing the level of agreement between HRECG and HRNellcor (A) and between HRECG and HRMasimo (B)

HRECG – HRNellcor

Mean Difference -0.8 bpm

95% Limit of Agreement ± 10.9 bpm

-100

-50

050

HR

from

EC

G m

inus

HR

from

Mas

imo

PO

(bpm

)

50 100 150 200Average of HR from ECG and HR from Masimo PO (bpm)

9.6

0.2

-9.3

10.1

-11.6

-100

-50

050

HR

from

EC

G m

inus

HR

from

Nel

lcor

PO

(bpm

)

50 100 150 200Average of HR from ECG and HR from Nellcor PO (bpm)

-0.8

Agreement between HR measurements

B A

Bland-Altman plots showing the level of agreement between HRECG and HRNellcor (A) and between HRECG and HRMasimo (B)

HRECG – HRNellcor HRECG – HRMasimo

Mean Difference -0.8 bpm 0.2 bpm

95% Limit of Agreement ± 10.9 bpm ± 9.4 bpm

Heart rate in the delivery room: What is normal?

Heart rate in healthy term babies (no interventions)

Oxygen saturations in the delivery room: What is normal?

O2 saturations in the first 10 mins 0

1020

3040

5060

7080

9010

0O

xyge

n sa

tura

tion

(%)

0 1 2 3 4 5 6 7 8 9 10Minutes after birth

10th 25th 50th 75th 90th

All babies no interventions in the delivery room

Defining the Reference Range for Oxygen Saturation for Infants After Birth. Pediatrics. 2010.

Don’t forget to look at the baby!

Measuring pressure and volume

Florian traces (200Hz) using Spectra software during ventilation

Pressure

Flow

Volume

Summary (1)

• “Colour” is no longer recommended as a useful sign in the DR

• Clinical assessment systematically underestimates true heart rate

Summary (2)

• Pulse oximetry is a useful guide to assessment of oxygenation and heart rate in the DR but: – Know what is normal – Look at the baby

• Signs of effective ventilation are imperfect – Respiratory function monitoring helps us

understand the problems


2013


Prof Stuart Hooper


Dr Jennifer Dawson


cardiovascular system – cardiovascular changes at birth · cardiovascular system –...

Documents