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.
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.
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.
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
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, 5th
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
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
• “5th
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 PaO2
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
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.
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
As an example, 3 g/dL of reduced hemoglobin is associated with an oxygen saturation of 67 percent when the total hemoglobin concentration is 9 g/dL, and 85 percent when the hemoglobin concentration is 20 g/dL.
This characteristic aids in fetal uptake of oxygen from the placenta but results in less oxygen delivery to the tissues
Those that increase the affinity of hemoglobin for oxygen (shifting the oxygen dissociation curve to the left), decrease the concentration of reduced hemoglobin at a given arterial P02, and lower the PO2 at which cyanosis first appears. These factors include alkalosis, hyperventilation (low PC02), cold temperature, and low levels of 2,3 diphosphoglycerate (show figure 2) [8] . In contrast, acidosis, fever, or increased adult hemoglobin shift the curve to the right. As a result, at a given arterial PO2, there is increased oxygen delivery to the tissues resulting in a greater concentration of reduced hemoglobin, and cyanosis appears more readily.
Methemoglobinemia- An oxidized form of hemoglobin, cannot carry oxygen and, when present in significant quantities, will cause cyanosis. Acquired or congenital disorder due to nicotinamide adenine dinucleotide (NADH) cytochrome b5 reductase deficiency and hemoglobin M disorder.
Lithium- Ebstein anomaly Fetal hydantoin synd- PS, AS Fetal alcohol- VSD,ASD Connective tissue disorder- congenital complete heart block associated with anti-Ro/SSA and anti-La/SSB antibodies. Congenital infections- cytomegalovirus, herpesvirus, rubella, or coxsackie virus can lead to cardiac structural abnormalities or functional impairment.
several of the most serious anatomic abnormalities, such as transposition of the great arteries, produce only a very soft murmur or no murmur at all.
Probe site — Postductal probe placement is the optimal site because defects with right-to-left shunting of desaturated blood through the ductus arteriosus will not be detected with preductal placement. Signal quality and infant behavior [28] — Measurements should not be performed when the infant is crying or moving as it reduces the quality of the signal and the accuracy of the test.
oxygen. With dyshemoglobinemia it is possible to have a substantial reduction in the blood’s oxygen carrying capacity and yet have normal functional saturation. Thus, normal functional saturation does not ensure adequate oxygen carrying capacity, so a functional saturation reading could mislead someone who did not know the difference between functional and fractional saturation- methemoglobinemia and carboxyhemoglobinemia