Approach to a neonate with cyanosis

1. Approach to a Neonate with
Cyanosis
Dr. Sunil Agrawal
1
st
yr MD pediatrics

2. Contents
•Introduction
•Central, Peripheral and Differential cyanosis
•Mechanism
•Etiology
•Approach
•Principles of Treatment
•Conclusion
•References

3. Introduction
•Bluish discoloration of the tissues that
results when the absolute level of reduced
hemoglobin in the capillary bed exceeds 3
g/dL
•Depends upon the total amount of
reduced hemoglobin rather than the ratio
of reduced to oxygenated hemoglobin.

4. Central cyanosis
•Pathologic condition caused by reduced
arterial oxygen saturation.
•Involves highly vascularized tissues, such
as the lips and mucous membranes,
through which blood flow is brisk and the
arteriovenous difference is minimal.
•Cardiac output typically is normal, and
patients have warm extremities.

5. Peripheral cyanosis
•Normal systemic arterial oxygen saturation
and increased oxygen extraction, resulting
in a wide systemic arteriovenous oxygen
difference
•The increased extraction of oxygen results
from sluggish movement of blood through
the capillary circulation

6. Peripheral cyanosis
•Causes-
–vasomotor instability, vasoconstriction caused
by exposure to cold, venous obstruction,
elevated venous pressure, polycythemia, and
low cardiac output
•Affects the distal extremities and
circumoral or periorbital areas .

7. Differential cyanosis
•Upper half of the body is pink and the
lower half cyanotic, or vice versa
•Requires pulmonary vascular resistance
elevated to a systemic level and a patent
ductus arteriosus.

8. Mechanism of cyanosis
•Alveolar hypoventilation
•Diffusion impairment
•Ventilation-perfusion mismatch
•Right-to-left shunting at the intracardiac,
great vessel, or intrapulmonary level
•Hemoglobinopathy (including
methemoglobinemia) that limits oxygen
transport

9. Factors affecting the detection of
cyanosis in the newborn
•Hemoglobin concentration -
–Detected at higher levels of saturation in
polycythemic than in anemic patients.
–Significant oxygen desaturation can be
present in an anemic patient without clinically
detectable cyanosis.

10. The arterial oxygen saturation level at which cyanosis is
detectable at different total hemoglobin concentrations is
illustrated above. The solid red portion of each bar represents 3
gm/dL reduced hemoglobin. Reproduced with permission from:
Lees, MH. Cyanosis of the newborn infant. J Pediatr 1970;
77:484.

11. Factors affecting the detection of
cyanosis in the newborn
•Fetal hemoglobin —
–Binds oxygen more avidly than adult hemoglobin.
–The oxygen dissociation curve is shifted to the left, so
that for a given level of oxygen tension (PO2), the
oxygen saturation (SO2) is higher in the newborn than
older infants or adults
–It also follows that for a given level of oxygen
saturation, the PO2 is lower in newborns.
–As a result, cyanosis is detected at a lower PO2 in
newborns compared with older patients. Thus, in
evaluating a cyanotic newborn, PO2 should be
measured in addition to SO2 to provide more
complete data.

12. Factors affecting the detection of
cyanosis in the newborn
•Other physiologic factors common in sick
newborns affect the oxygen dissociation
curve.

13. The oxygen-dissociation curve of human blood and the effects of changes in
the H+ ion concentration, Pco2 temperature and level of 2, 3-diposphoglycerate
(2,3-DPG) are depicted above. For fetal hemoglobin, the normal curve (a) is
shifted to the left (b). Reproduced with permission from: Levin, AR.
Management of the cyanotic newborn. Ped Ann 1981; 10:127. Copyriht ©1981
SLACK, Inc.

14. Factors affecting the detection of
cyanosis in the newborn
•Skin pigmentation -
–Less apparent in the skin of patients with
darker pigmentation.
–Examination should include the nail beds,
tongue, and mucous membranes, which are
less affected by pigmentation.

15. Etiology

16. Non- cardiac causes
•Alveolar hypoventilation
–Central nervous system depression: asphyxia,
maternal sedation, intraventricular
hemorrhage, seizure, meningitis, encephalitis
–Neuromuscular disease: Werdnig-Hoffman
disease, neonatal myasthenia gravis, phrenic
nerve injury
–Airway obstruction: choanal atresia,
laryngotracheomalacia, macroglossia, Pierre
Robin syndrome

17. Non- cardiac causes
•Ventilation/perfusion mismatch
–Airway disease: pneumonia, aspiration, cystic
adenomatoid malformation, diaphragmatic hernia,
pulmonary hypoplasia, labor emphysema, atelectasis,
pulmonary hemorrhage, hyaline membrane disease,
transient tachypnea of the newborn
–Extrinsic compression of lungs: pneumothorax,
pleural effusion, chylothorax, hemothorax, thoracic
dystrophy

18. Non-cardiac causes
•Hemoglobinopathy
–Methemoglobinemia: congenital or secondary to toxic
exposure
–Other hemoglobinopathies
•Diffusion impairment
–Pulmonary edema: left-sided obstructive cardiac
disease, cardiomyopathy
–Pulmonary fibrosis
–Congenital lymphangiectasia

19. Cardiac causes
•Decreased pulmonary blood flow-
–Tetralogy of Fallot
–Tricuspid valve anomaly
–Pulmonary valve atresia
–Critical valvular pulmonary steanosis
•Increased pulmonary blood flow-
–Transposition of great arteries
–Truncus arteriosus
–Total anomalous pulmonary venous connection

20. Cardiac causes
•Severe heart failure-
–Hypoplastic left heart syndrome
–Coarctation of the aorta
–Interrupted aortic arch
–Critical valvular aortic steanosis

21. Mnemonic
•Cardiac causes- "five Ts" of cyanotic CHD:
–Transposition of the great arteries
–Tetralogy of Fallot
–Truncus arteriosus
–Total anomalous pulmonary venous connection
–Tricuspid valve abnormalities.
•A sixth "T" is often added for "tons" of other diseases,
such as double outlet right ventricle, pulmonary atresia,
multiple variations of single ventricle, hypoplastic left
heart syndrome, or anomalous systemic venous
connection (left superior vena cava connected to the left
atrium).

22. Differential cyanosis
•With normally related great arteries, oxygen
saturation may be higher in the upper than lower
extremity in patients if there is right-to-left
shunting through the ductus arteriosus.
•Seen with severe coarctation or interrupted
aortic arch.
•May also occur in patients persistent pulmonary
hypertension of the newborn
•The differential effect is reduced if there is also
right-to-left shunting at the level of the foramen
ovale, or if there is left-to-right shunting across a
coexisting ventricular septal defect

23. Differential cyanosis
•Reversed differential cyanosis is a rare
finding that may occur in patients with
transposition of the great arteries
associated with either coarctation or
pulmonary hypertension.
•In these infants, oxygen saturation is
higher in the lower than upper extremity.

24. Approach

25. Aim
•Differentiate physiologic from pathologic
cyanosis
•Differentiate cardiac from non- cardiac
cause of cyanosis
•Find cause which needs urgent treatment
or referral

26. Not so serious
•Acrocyanosis
–Bluish color in the hands and feet and around the
mouth (circumoral cyanosis). The mucus membranes
generally remain pink.
–Reflects benign vasomotor changes in the diffuse
venous structures in the affected areas.
–Does not indicate pathology unless cardiac output is
extremely low, resulting in cutaneous vasoconstriction
•Cyanosis soon after birth- transition from
intrauterine to extrauterine life
•Hand or leg prolapse

27. Perinatal history
•Drug intake
–Causing neonatal depression
–Lithium- Ebstein anomaly
–Phenytoin- PS and AS
•Maternal diabetes-
–TGA, ventricular septal defect (VSD), and
hypertrophic cardiomyopathy
•Connective tissue disorder- Heart blocks
•Congenital intrauterine infections
•Antenatal fetal echocardiography

28. History
•Methemoglobinemia may be acquired
following exposure to aniline dyes,
nitrobenzene, nitrites, and nitrates.

29. Onset of cyanosis in cardiac lesions-
•Depends on-
–Nature and severity of the anatomic defect
–In utero effects of the structural lesion
–Alterations in cardiovascular physiology
secondary to the effects of transitional
circulation like closure of ductus arteriosus
and the fall in pulmonary vascular resistance

30. Onset of cyanosis in cardiac lesions
Age on admission In order of frequency
0-6 days D- transposition of great arteries
Hypoplastic left ventricles
Tetralogy of fallot
7-13 days Coarctation of aorta
Hypoplastic left ventricle
D-transposition of great arteries
Tetralogy of fallot
14-28 days Coarctation of aorta
Tetralogy of fallot
D- transposition of great arteries
Neonatology- Pathophysiology and management of newborn, 5
th
edition ed.
1999. Philadelphia; Lippincott Williams and Wilkins

31. History- Risk factors
•Pneumonia/ sepsis-
–PROM
–Foul smelling liquor
–Maternal pyrexia
–Maternal GBS
•TTN –
–Birth by cesarean section
with or without labor
–Male sex
–Family history of asthma
(especially in mother)
–Macrosomia
–Maternal diabetes
•Polycythemia-
–small-for-gestational age
•MAS-
–Post maturity
–Small for gestational age
–Placental dysfunction
–Fetal distress
–Meconium stained liquor
•Pneumothorax-
–Aggressive resucitation
–IPPV
–Meconiun aspiration
–HMD
–Hypoplastic lung
–Staph pneumonia
•Hyaline membrane
disease-
–Premature infant
–Infant of diabetic mother

32. History
•Choanal atresia-
–Cyanosis decreases during crying
–Confirmed by failure to pass a soft No. 5F to
8F catheter through each nostril

33. Physical Examination
•Vital signs-
–Hypothermia or hyperthermia- infection.
–Tachycardia-hypovolemia.
–Weak pulses- Hypoplastic left heart
syndrome or hypovolemia.
–Pulses or blood pressures stronger in
the upper than in the lower extremities-
coarctation of the aorta.

34. Physical Examination
•Congenital heart disease-
–Respirations often are unlabored unless there
is pulmonary congestion or complicated by
the development of heart failure or acidosis,
which will affect the respiratory pattern.
•CVS-
–Presence or absence of a heart murmur is of
little assistance. Loud S2 suggests pulmonary
or systemic hypertension or malposition of the
aorta.
•

35. Physical Examination
•Inspiratory stridor-
–upper airway obstruction
•Chest-
–Asymmetric chest movement combined with
severe distress-
•alarming sign for tension pneumothorax,
diaphragmatic hernia
–Transillumination of the chest-
•Pneumothorax on an emergent basis

36. Physical Examination
P/A-
–Scaphoid abdomen
•Congenital diaphragmatic hernia
–Hepatosplenomegaly-
•congestive heart failure, maternal diabetes,
or congenital infection.

37. Physical Examination
•Central nervous depression-
–Causes shallow, irregular respirations and
periods of apnea.
–Affected infants typically appear hypotonic
and lethargic.

38. Pulse oximetry screening
•Difficulty in visual detection of cyanosis
•Potentially severe consequences of missing an
early sign of CHD
•“5
th
vital sign”
•Sensitivity and specificity varies-
–Criteria used for abnormal test
–Timing of screening
–Probe site
–Quality of the equipment
–Signal quality and neonate behaviour
–Health care workers expertise

39. Pulse Oximetry
•Oxygen saturation should be performed
initially on room air to serve as a baseline.
•Subsequently can be served to
differentiate between cardiogenic and non-
cardiogenic causes

40. Limitations of pulse oximetry
•effects of ambient light
•skin pigmentation
•dyshemoglobinemia
•low peripheral perfusion states
•motion artifact

41. Hyperoxia test
•If a low-pulse oximeter reading persists, it
may be appropriate to proceed to a
hyperoxia test. It is indicated if the pulse
oximeter reading is less than 85% in both
room air and 100% oxygen
•It is not recommended in preterm infants.

•Useful in distinguishing cardiac from
pulmonary causes of cyanosis.

42. Hyperoxia test
•Arterial oxygen tension is measured in the right
radial artery (preductal) and in a lower extremity
artery while the patient breathes 100 percent
oxygen (postductal).
•Pulse oximetry cannot be used- in neonate given
100% inspired O2 a value of 100% saturation
may be obtained with an arterial PO2 ranging
from 80 torr( abnormal) to 680 torr (normal)

43. Hyperoxia test
Disease Result- Increase
in PaO
2
Lung disease is more likely than
CHD
>150 mmHg
TGA or severe pulmonary outflow
obstruction
<50 to 60 mmHg
In lesions with intracardiac mixing
and increased pulmonary blood
flow such as truncus arteriosus-
>75 to 150
mmHg

44. Differential cyanosis
•To detect differential cyanosis, oxygen
saturation should be measured in sites
that receive blood flow from both preductal
(right hand) and postductal (foot) vessels.
It is preferable to use the right (rather than
left) upper extremity, since the left
subclavian artery arises close to the
ductus arteriosus, and some of its flow
may come from the ductus and thus not
reflect preductal values

45. Investigation
•Hematocrit or hemoglobin
•Sepsis screening
•Blood glucose concentration
•Arterial blood gases (Pao2, Paco2, pH)
•Blood cultures
•Electrocardiography
•Echocardiography, cardiac catheterisation,
angiocardiography
•Hemoglobin electrophoresis- Hb M

46. Chest X-Ray
•Aberrancy of the cardiothymic silhouette-
–Suggest the presence of structural heart
disease, and
–Abnormalities of the lung fields may be helpful
in distinguishing a primary pulmonary problem
such as meconium aspiration

47. Chest X- Ray
•Pulmonary vascular markings-
–Decreased in CHD with obstructed pulmonary
blood flow such as tetralogy of Fallot, severe
pulmonary stenosis or atresia, and tricuspid
atresia.
–Increased in admixture lesions like
transposition of the great arteries, total
anomalous pulmonary venous connection,
and truncus arteriosus.

48. Total Anomalous Pulmonary
Venous Return
•Snowman

49. Tetralogy of Fallot
•Boot
shape

50. Transposition of Great
Arteries
•Egg on a
string

51. Investigation
•If central cause-
– appropriate scan and drug levels
•Methemoglobinemia-
–Place few drops of pt blood on filter paper
–Appear chocolate brown

52. Treatment
•Goals-
–Provide adequate tissue oxygen and CO2
removal
•Principles-
–Establish airway
–Ensure oxygenation
–Ensure adequate ventilation
–Correct metabolic abnormalities
–Alleviate the cause of respiratory distress

53. Treatment- Buy time
•Prostaglandin E1
–For ductal dependant CHD/ reduced
pulmonary blood flow- Fail hyperoxia test( An
arterial PO2 of less than 100 torr in the
absence of clear- cut lung disease)
–Infusion of prostaglandin E1 at a dose of 0.05-
0.1mcg/kg/min intravenously to maintain
patency

54. Treatment- buy time
•Prostaglandin E1-
–S/E- hypoventilation, apnea, edema and low
grade fever
–Benefits- Can be stabilized more easily,
allowing for safe transport to a tertiary care
center. More time is also available for
thorough diagnostic evaluation and patients
can be brought to surgery in a more stable
condition.

55. Conclusion
•Identify those that are life-threatening.
•complete maternal and newborn history
•perform a thorough physical examination
•recognize the common respiratory and
cardiac disorders
•differentiate among various diagnostic
entities
•For ductal dependent lesion, start
prostaglandin E1 and early referral

56. References
•Nelson textbook of pediatrics
•Cloherty manual of neonatal care
•Approach To Cyanotic Heart Disease In The First Month
Of Life , Harry J. D'Agostino, Jr., M.D. and Eric L.
Ceithaml, M.D.
•Pediatrics in Review. 1999;20:350-352.)
© 1999, Consultation with the Specialist, Nonrespiratory
Cyanosis, Jon Tingelstad, MD
•UpToDate