Approach to a Neonate with Cyanosis
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Transcript of Approach to a Neonate with Cyanosis
Dr.Afnan Shamraiz
Contents Introduction Central, Peripheral and Differential
cyanosis Mechanism Etiology Approach Principles of Treatment Conclusion
IntroductionCyanosis is derived from the colour ‘cyan’, which
comes from ‘kyanous’, the Greek word for blue It is defined as the bluish discoloration of the skin
and the mucous membranes, resulting from an increase in the reduced Haemoglobin or of haemoglobin derivatives in the small vessels of those areas.
Bluish discoloration of the tissues that results when the absolute level of reduced hemoglobin in the capillary bed exceeds 3- 4 g/dL
Depends upon the total amount of reduced hemoglobin rather than the ratio of reduced to oxygenated hemoglobin.
Sites to detect cyanosis Lips Nail beds Ears Malar Prominences Palms and Soles Tongue Mucous membranes of gum,soft palate,cheeks
Types of Cyanosis Central Cyanosis Peripheral Cyanosis Mixed Cyanosis
Other Types Enterogenous/Pigment Cyanosis Differential Cyanosis Acrocyanosis Orthocyanosis
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.
Mechanism Decreased arterial oxygen saturation due to
marked decrease in oxygen tension in the arterial blood(arterial PaO2 is reduced)
Sites- Tongue (margins & undersurface) Inner aspect of lips Mucous membranes of gums,soft palate,cheeks
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 .
Mechanism 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
• Sites• Tip of nose• Ear lobules• Outer aspect of lips,chin,cheek• Tips and nailbeds of fingers,toes• Palms,soles
Mixed Cyanosis
Cardiogenic shock+ pulmonary oedema CCF due to lt.sided heart failure Polycthemia (rare)
Orthocyanosis Present in upright position due to hypoxia
occuring in erect posture in Pulmonary Arteriovenous Malformation
Enterogenous/pigment cyanosis Due to presence of excessive –
sulphaemoglobin(>0.5g/dl),methaemoglobin(>1.5g/dl
Causes Hereditary haemoglobin M disease Poisoning by aniline dyes Drugs-
nitratres,nitrites,phenacetin,sulphonamides Carboxyhaemoglobinaemia
Differential Cyanosis Hands red (less blue) and feet blue seen in PDA with reversal of
shunt (Differential Cyanosis) Requires pulmonary vascular resistance elevated to a systemic level and a patent ductus arteriosus
L R shunt
Pulmonary hypertension
R to L
Reversal of shunt
Desaturated blood from the ductus enters the aorta distal to the left subclavian artery, sparing the brachiocephalic circulation.
Reverse Differential Cyanosis Hands blue and feet red seen in
Coarctation of Aorta with TGA(Reverse Differential Cyanosis
Intermittent Cyanosis seen in Ebstein’s Anomaly
Central Vs Peripheral Cyanosis SITES TONGUE,ORAL CAVITY TONGUE UNAFFECTED
HANDSHAKE FEELS WARM FEELS COLD
APPLICATION OF WARMTH,COLD
NO CHANGE WARMTH-CYANOSIS INCR,COLD-DECREASES
APPLICATION PURE O2 MAY IMPROVE NO RESPONSE
CLUBBING,POLYCYTHAEMIA
USUALLY PRESENT ABSENT
PULSE VOLUME MAYBE HIGH LOW VOL
DYSPNOEA PT BREATHLESS NO RESPIRATORY PROBLEM
Acrocyanosis
Condition in which there is arterial vasoconstriction,and secondary dilation of capillaries and venules with resulting persistant cyanosis of the hands and less fequently the feet.part of normal transitionmay last 72hrbeware APGAR of 10
○ hypoperfused○ severe anemia
Psuedocyanosis
Bluish tinge to the skin and or mucous membranes that is not associated with either Hyoxemia or Peripheral Vasoconstriction
Metals Drugs
Factors altering cyanosis
Colour of the cutaneous pigment Thickness of the skin State of cutaneous capillaries
Cyanosis becomes apparent when the concenteration of the reduced haemoglobin in capillary blood vessels exceeds 40 g/l or 4g/dl
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.
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.
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.
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.
Factors affecting the detection of cyanosis in the newborn Other physiologic factors common in
sick newborns affect the oxygen dissociation curve.
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
For fetal hemoglobin, the normal curve (a) is shifted to the left (b)
Cyanosis
0
10
20
30
40
50
60
70
80
90
100
0 20 40 60 80
HCT
% S
atu
rati
on
Cyanosis…
Cyanosis is dependent on HCT and % Sat
Florescent light makes cyanosis hard to see.
Except in the extreme, cyanosis is not obvious
Any question, check a pulse ox
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.
For fetal hemoglobin, the normal curve (a) is shifted to the left (b)
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.
Etiology Can be divided in to,,
Site of cynosis Central causes Peripheral causes
Mecanism of cynosis
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
Central Cyanosis:- Decreased arterial oxygen saturation Decreased atmospheric pressure-High altitude Impaired pulmonary function Alveolar hypoventilation Pulmonary ventilation perfusion imbalance Impaired oxygen diffusion Anatomic Shunts –ASD,VSD,PDA Congenital Heart Diseases-Fallots Tetrology,TGA Pulmonary AV fistulas Mutiple small intrapulmonary shunts Haemoglobin Abnormalities
Peripheral Cyanosis Decreased Cardiac Output Cold Exposure Redistribution Of blood from extremities Arterial Obstruction-embolus,raynauds
phenomenon Venous Obstruction-thrombophlebitis,SVC
syndrome Frost bite CCF,shock,Peripheral Circulatory Failure Hyperviscosity -Multiple myeloma,Polycythemia Peripheral Vascular Diseases-
atherosclerosis,buerger’s Mitral Stenosis Cryoglobulinemia
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
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
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
Cardiac causes Decreased pulmonary blood flow-
Tetralogy of FallotTricuspid valve anomalyPulmonary valve atresiaCritical valvular pulmonary steanosis
Increased pulmonary blood flow-Transposition of great arteriesTruncus arteriosusTotal anomalous pulmonary venous connection
Cardiac causes
Severe heart failure-Hypoplastic left heart syndromeCoarctation of the aortaInterrupted aortic archCritical valvular aortic steanosis
The 6 T’s
Total Anomalous Pulmonary Veins Tetrology of Fallot Tricuspid Atresia Transposition Truncus Arteriosus
Total AcardiaTotal Acardia
Mnemonic
A 7T" 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
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
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.
Aim
Differentiate physiologic from pathologic cyanosis
Differentiate cardiac from non- cardiac cause of cyanosis
Find cause which needs urgent treatment or referral
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
Perinatal history Drug intake
Causing neonatal depression Lithium- Ebstein anomaly Phenytoin- PS and AS Fetal hydantoin synd- Fetal alcohol- VSD,ASD
Maternal diabetes- TGA, ventricular septal defect (VSD), and hypertrophic
cardiomyopathy Connective tissue disorder- Heart blocks associated with
anti-Ro/SSA and anti-La/SSB antibodies. Congenital intrauterine infections cytomegalovirus,
herpesvirus, rubella, or coxsackie virus can lead to cardiac structural abnormalities or functional impairment
Antenatal fetal echocardiography
History
Methemoglobinemia may be acquired following exposure to aniline dyes, nitrobenzene, nitrites, and nitrates.
Advanced maternal age Trisomy 21 associated with many congenital heart defects (cyanotic and acyanotic)
Oligohydramnios …..Pulmonary hypoplasia
Onset of cyanosis in cardiac lesions-
Depends on-Nature and severity of the anatomic defectIn utero effects of the structural lesionAlterations in cardiovascular physiology secondary
to the effects of transitional circulation like closure of ductus arteriosus and the fall in pulmonary vascular resistance
A ductal dependent lesion is one that depends on the ductus to get adequate blood flow to the pulmonary and systemic circuits, or provide mixing
○ PS
○ CoA○ TGA
Labour Hx Associated causes of cyanosis
•PROM, fever, GBS +ve •Sepsis
•Sedatives/anesthetics •Respiratory depression, apnea
•C-section •TTN, PPHN
•Preterm infant •RDS
•Meconium •MAS (pneumonia)
Onset of cyanosis in cardiac lesionsAge 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
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
History Choanal atresia-
Cyanosis decreases during cryingConfirmed by failure to pass a soft No. 5F to
8F catheter through each nostril
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.
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.
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
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
Physical Examination
P/A-Scaphoid abdomen
○ Congenital diaphragmatic hernia
Hepatosplenomegaly-○ congestive heart failure, maternal diabetes,
or congenital infection.
Physical Examination
Central nervous depression-Causes shallow, irregular respirations and
periods of apnea.Affected infants typically appear hypotonic
and lethargic.
Investigations CBC & diff : Increase or decrease WBC : sepsis Hematocrit > 65% : polycythemia Serum glucose: to detect hypoglycemia Arterial Blood Gases (ABGs): Arterial PO2: to confirm central cyanosis : SaO2 not as
good an indicator due to Increase fetal Hb affinity for O2 (left-shift)
Increase PaCO2: may indicate pulmonary or CNS disorders, heart failure
Decrease pH: sepsis, circulatory shock, severe hypoxemia Methemoglobinemia: Decrease SaO2, normal PaO2,
chocolate-brown blood
If central cause- appropriate scan and drug levels
Hb electropheresis…..Hb M Decrease pH: sepsis, circulatory shock,
severe hypoxemia Decrease pH: sepsis, circulatory shock,
severe hypoxemia Sepsis screening
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 testTiming of screeningProbe siteQuality of the equipmentSignal quality and neonate behaviourHealth care workers expertise
Signal quality and infant behavior — 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 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
Terms
PaO2 Arterial Oxygen Pressure
Measured on an ABG machine Oxygen dissolved in plasma
○ 0.003 ml O2/mmHg/dl plasma
SaO2 Percent Oxygen Saturation
Measured by saturation monitor (pulse-Ox) ~1.34ml O2/g Hb
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
Useful in distinguishing cardiac from
pulmonary causes of cyanosis.
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).
Hyperoxia Test
Infant on Room Air, get ABG Infant on 100% oxygen, get ABG PaO2 unchanged = fixed shunt = CCHD
Max PaO2 <100 = CCHD
Max PaO2 >200 = No CCHD
Hyperoxia testDisease 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
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
Chest X-Ray To identify pulmonary causes of cyanosis:
pneumothorax, pulmonary hypoplasia, diaphragmatic hernia, pulmonary edema, pleural effusion, etc.
Useful in evaluating congenital heart disease: e.g., cardiomegaly & vascular congestion: heart failure
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
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.
Total Anomalous Pulmonary Venous Return
Snowman
Tetralogy of Fallot
Boot shape
Transposition of Great Arteries
Egg on a string
Echocardiography
Indicated if abnormal cardiac examination suggestive of congenital heart defect, failed hyperoxia test (cardiac disease suspected) or has unclear diagnosis
Treatment Goals-
Provide adequate tissue oxygen and CO2 removal
Principles-Establish airwayEnsure oxygenationEnsure adequate ventilationCorrect metabolic abnormalitiesAlleviate the cause of respiratory distress
Monitor Airway, breathing, circulation (ABCs) with respiratory compromise, establish an airway & provide supportive therapy (e.g., oxygen, mechanical ventilation)
Monitor Vital signs Establish vascular access for sampling blood &
administering meds (if needed): umbilical vessels convenient for placement of intravenous & intraarterial catheters
If sepsis is suspected or another specific cause is not identified, start on broad spectrum antibiotics (e.g., ampicillin and gentamycin) after obtaining a CBC, urinalysis, blood & urine cultures (if possible). Left untreated, sepsis may lead to pulmonary disease & left ventricular dysfunction.
.
An infant who fails the hyperoxia test & does not have PPHN or a CXR showing pulmonary disease likely has a congenital heart defect that’s ductus-dependent. If cardiac disease is suspected, immediately start PGE1 infusion. Complications of PGE1 infusion include hypotension, tachycardia, apnea. Secure a separate intravenous catheter to provide fluids for resuscitation and ensure accessibility of intubation equipment should they be required
Treatment-
Prostaglandin E1For 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
Treatment-
Prostaglandin E1-S/E- hypoventilation, apnea, edema and low
grade feverBenefits- 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.
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
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
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