neonatal cyanosis
Introduction
Introduction to newborn cyanosis Cyanosis, also known as purpura, is a manifestation of increased hemoglobin concentration in the blood and on the skin and mucous membranes. It is more likely to occur in areas where the skin is thinner, the pigment is less, and the capillaries are more abundant, such as the lips and fingers. Toes) Tips, tip of the nose, and earlobe. Hair blemishes can be caused by insufficient airway in the lungs. It is also a symptom of many right-to-left shunt congenital heart diseases, and can also be seen in central nervous system damage and certain blood diseases. basic knowledge The proportion of the disease: the incidence rate is about 0.1% - 0.3%, more common in the intrauterine hypoxia Susceptible people: children Mode of infection: non-infectious Complications: brain edema metabolic acidosis
Cause
Neonatal bruising
(1) Causes of the disease
Temporary bruising
(1) Physiological cyanosis: Normal newborns may present cyanosis within 5 minutes after birth, because the arterial catheter and the foramen ovale have not been closed, and still maintain a right-to-left shunt, the lung has not fully expanded, and the lung ventilation function is not Perfect, and poor perfusion of blood around the skin, 5 minutes later, the circulatory system has been changed, the arteriovenous blood flow is completely separated, the lips and nail bed become pink, but sometimes the skin is still mild cyanosis, especially after birth Exposed to the cold environment, the local blood flow at the distal end of the limb becomes slower and the reduced hemoglobin increases. Therefore, although PaO2 is not low, the limbs are still obviously cyanotic, which is called peripheral cyanosis. After strengthening the heat preservation, cyanosis can be alleviated or disappeared.
(2) Temporary bruising: Normal newborns may appear cyanosis when crying hard, because the intrathoracic pressure increases when crying, the right atrial pressure rises, exceeds the left atrial pressure, and forms the right to left through the oval hole. Diversion, this temporary bruising disappears immediately after the crying stops.
2. Central cyanosis is caused by cardiopulmonary disease, which reduces arterial SO2 and PaO2. It can be divided into pulmonary and cardiogenic according to the cause.
(1) pulmonary-induced bruising: such as neonatal asphyxia, congenital malformations of the respiratory tract such as Pierre-Robin syndrome, posterior nostril obstruction, hyaline membrane disease, pulmonary insufficiency, pneumonia, emphysema, pneumothorax, congenital paralysis, congenital Pulmonary arteriovenous fistula, continuous fetal circulation, etc.
(2) Cardiac cyanosis: Congenital heart disease with right-to-left shunt, common in the neonatal period, tetralogy of Fallot, large vessel translocation, left ventricular dysplasia syndrome, pulmonary venous return , total arterial trunk, tricuspid atresia and severe pulmonary stenosis.
3. Peripheral cyanosis due to blood circulation through the surrounding capillary, the blood flow rate is slow, the tissue oxygen consumption increases, and the amount of local reduced hemoglobin increases, but the arterial SO2 and PaO2 are normal.
(1) Systemic diseases: slow circulation of blood circulation during heart failure, decreased cardiac output during shock, decreased peripheral blood supply, stagnant blood flow in capillaries, increased blood viscosity during polycythemia, and low sclerosis When the body temperature is reduced, the blood flow is reduced, and the blood flow can be slowed down and cyanosis appears.
(2) local blood flow disorder: the first exposed part of the body is stressed, such as the face, hips, etc. can appear cyanosis, in addition to neonatal physiological conditions, the limbs can also appear cyanosis.
Other respiratory failures such as central nervous system disorders, hypoglycemia, secondary apnea caused by hypocalcemia, abnormal hemoglobin such as hereditary methemoglobinemia, acquired methemoglobinemia, M-hemoglobinemia, etc. Can cause cyanosis.
(two) pathogenesis
Cardiac cyanosis is seen in right-to-left shunt congenital heart disease. The venous blood that fails to pass through the lungs and the oxygen in the alveoli is directly shunted into the arterial system, resulting in excessive reduction of hemoglobin in the arterial blood and cyanosis. The mechanism of sexual cyanosis hypoxia is caused by insufficient ventilation and insufficient ventilation. It is seen in various malformations and inflammatory diseases of the respiratory system. Intracranial hemorrhage in neonates, especially intraventricular hemorrhage in premature infants, can often cause cyanosis. Inhibition of the respiratory center, repeated episodes of apnea, affecting gas exchange, peripheral vasomotor dysfunction is another cause, severe microcirculatory disorders cause tissue hypoxia, leading to significant hypoxemia and metabolic acidosis.
Hemoglobin is a substance that carries oxygen. When blood flows through the alveoli, hemoglobin combines with oxygen to form oxygenated hemoglobin and color red. When blood flows to the whole body, oxygenated hemoglobin releases oxygen to the tissue for utilization, and is converted into reduced hemoglobin, color purple, normal. The blood contains 2 to 3 g/dl of reduced hemoglobin. When the content is increased to 5 g/dl, cyanosis appears in the clinic.
Cyanosis generally indicates hypoxia, but the meanings of cyan and hypoxia are not exactly the same. For example, children with carbon monoxide or cyanide poisoning and extreme anemia do not show cyanosis despite severe hypoxia. People in the plateau, through the increase of compensatory red blood cells and hemoglobin, can be roughly overcome by hypoxia and still have significant cyanosis.
The amount of oxygen saturation in newborns is significantly increased after birth, but the absolute amount of reduced hemoglobin is still high, so the nail bed often has mild purple, and because it has relatively more oxygen-carrying hemoglobin, it is not accompanied by irritability. , anxious and other symptoms of hypoxia.
Prevention
Neonatal cyanosis prevention
1. For neonatal cyanosis, timely treatment with oxygen. Hair blemishes suggest hypoxia in the body, which may cause damage to vital organs such as the brain, heart, kidney, lungs, etc., which may affect their mental and physical development.
2. In the home, oxygen can be produced by oxygen generators to meet the neonatal needs for oxygen. But be sure to choose absolutely safe equipment, and the oxygen generator should have no side effects. The use of a home oxygen generator wins time for the treatment of neonatal hypoxia, avoiding irreversible damage to organ development and mental development due to long periods of hypoxia.
3. When nursing newborns, keep warm, keep the airway open, and prevent milk and vomit from licking the trachea.
4. Intermittent milk, do not let the baby suck for a long time.
Complication
Neonatal cyanosis complications Complications brain edema metabolic acidosis
Patients with severe illness or not received timely treatment, prone to respiratory, circulatory failure, brain damage due to hypoxia, cerebral edema, hypoxic ischemic encephalopathy, etc., severe microcirculatory disorders cause tissue hypoxia, resulting in significantly lower Oxygenemia and metabolic acidosis are manifestations of a sharp deterioration in the condition.
Symptom
Newborn cyanosis symptoms Common symptoms Oral mucosa showing blue-violet dyspnea mouth mouth breathing erythrocytosis hug reflex disappearing respiratory irregular respiratory failure apnea
Check whether the newborn has cyanosis in the sun, carefully observe the oral mucosa, nail bed and eye-bound membrane, usually see the cyanosis when the naked eye, the arterial blood reduced hemoglobin has reached 50g / L (5g / dl) or more, oral mucosa bruising At the earliest, when the hemoglobin was reduced to 30g/L (3g/dl), it was blue-violet. To check whether the newborn has cyanosis, the following two points should be considered:
1 Newborns show cyanosis in the case of PaO2, which is lower than that of adults. Because of the higher fetal hemoglobin in the blood of newborns, the affinity with oxygen is higher.
2 The concentration of hemoglobin in newborns varies greatly. There are various causes of anemia, and there may be polycythemia. When erythrocytes increase, cyanosis occurs when the reduced hemoglobin reaches a high level. In severe anemia, oxyhemoglobin decreases. Cyanosis can be seen at very low levels.
The main performance characteristics of various diseases with bruising are as follows:
1. Congenital heart disease: In addition to blue UV, there are signs of heart disease, more than a short time after birth, cyanosis, cyanosis is persistent, oxygen can not be lifted.
2. Posterior nostril atresia: Dyspnea and bruising occur at birth or shortly after birth. It is characterized by the disappearance of bruising when Zhangkou is crying, and the appearance of cyanosis when closing and sucking, such as pressing the tongue root with a tongue depressor, cyanosis Difficulty breathing is immediately relieved. The disease is a neonatal emergency. If both sides of the nostrils are locked, the newborn will not breathe and can cause suffocation and death.
3. Jaws with small jaws: When you are born, you will see small jaws, fissures, tongue shifting, difficulty breathing, paroxysmal bruising, and cyanosis on the back. If you push the tongue forward, the bruising will be relieved immediately.
4. Congenital esophageal atresia (with tracheal fistula): bruising occurs during feeding, accompanied by cough (caused by milk entering the respiratory tract), no cyanosis occurs when no milk is fed, but the mouth is often flowing.
5. Congenital diaphragm: There is persistent or paroxysmal bruising after birth, and the breathing is difficult. It is aggravated when feeding. It occurs on the left side. The percussion is a drum sound. The auscultation can be heard and the bowel sounds, mainly due to The intra-abdominal organs enter the chest, the heart, the large blood vessels, and the lungs are compressed or displaced. X-ray examination can help diagnose.
6. Placental vascular malformation: seen in the double fetus, there is bruising after birth, and there is irritability, due to abnormal placental blood vessels, receiving the blood of another fetus, causing red blood cells and hemoglobin is too high, another fetus has obvious anemia Can help diagnose.
7. Congenital metabolic defects: common inherited methemoglobinemia, there is cyanosis after birth, effective treatment with methylene blue or vitamin C, can be identified.
8. Neonatal asphyxia: When you are born, you will see the whole body bruising, suffocation, severe shock, facial and body pale and cyanotic lips, and many causes of hypoxia, such as long labor, placental abruption, maternal anesthesia Medicine, etc.
9. Neonatal intracranial hemorrhage: lighter can breathe on their own, but irregular breathing or apnea, intermittent cyanosis, severe suffocation at birth, whole body bruising, often cerebral screams, full suffocation, The size of the pupils is not equal, the sputum reflexes, and the hug reflection disappears.
10. sacral nerve injury: seeing difficulty breathing after birth, bruising, no abdominal abdomen during inhalation, weakened respiratory movement on the affected side of the chest, percussion dullness, decreased breath sounds, X-ray examination can help diagnose.
11. Neonatal pneumothorax: There is a history of dystocia, there is bruising after urinary, rapid, the chest is full, respiratory movement is reduced, the loudness of the percussion is enhanced, the breath sound disappears, the apex beats to the healthy side, X-ray examination can help diagnose.
12. Neonatal atelectasis: irregular breathing after birth, suffocation, bruising, bruising, paroxysmal, bruising or disappearing when crying, bruising or persistence during apnea, inconsistent signs of both lungs, sometimes affected side Local voiced sound.
13. Neonatal respiratory distress syndrome: occurs mostly in immature children, breathing at birth, normal heartbeat, bruising after a few hours, difficulty breathing, progressive aggravation, death due to respiratory failure, heart failure.
14. Neonatal pneumonia: bruising within a few days after birth, shallow breathing and irregular, foaming at the mouth, not eating, not crying, the lungs often have no typical pneumonia signs.
Examine
Examination of neonatal bruising
The arterial blood is taken for blood gas. If PaO2 is below 5.3 kPa (40 mmHg), it can be determined as cyanosis. Generally, after inhaling pure oxygen, if PaO2 rises above 33.25 kPa (250 mmHg), the right-to-left shunt caused by any reason can be excluded.
When the placental vascular malformation occurs, the blood red blood cells and hemoglobin of one fetus are too high, and the other fetus has obvious anemia.
In methemoglobinemia, when the methemoglobin concentration is 15g/L (1.5g/dl), the blood is dark brown and the skin and mucous membranes appear cyanotic.
1. X-ray chest X-ray: to determine whether there is cardio-pulmonary disease, such as congenital heart disease, congenital esophageal atresia (with tracheal fistula), congenital diaphragmatic hernia, radial nerve injury, neonatal pneumothorax, neonatal atelectasis, newborn Pediatric pneumonia and other characteristics have corresponding X-ray characteristics.
2. Others: According to the condition, choose B-ultrasound, electrocardiogram, CT, etc. If you suspect that the newborn is intracranial hemorrhage, you can do a CT scan of the brain to confirm the diagnosis.
Diagnosis
Diagnosis of neonatal bruising
diagnosis
If you want to confirm whether there is cyanosis in the clinic, you should immediately do blood gas analysis. If you are diagnosed as central cyanosis by PaO2, you should find the cause as soon as possible, and correct hypoxemia in time to avoid the disease, and confirm the diagnosis according to clinical observation. Tablets, blood gas analysis, electrocardiogram and echocardiography, and other necessary examinations to determine whether there is a heart or lung disease.
Should carefully check the respiratory rate, depth, with or without inspiratory depression and expiratory sputum, with or without nasal wing fan, and X-ray chest X-ray, generally mild cyanosis with obvious three concave signs, suggesting lung lesions; severe cyanosis With mild three concave signs, mostly congenital heart disease; cyanosis without any breathing difficulties is more consistent with methemoglobinemia; cyanosis caused by craniocerebral diseases often have superficial breathing, irregular rhythm and even apnea; by sepsis, The cyanosis caused by shock is shallow and fast, and the three concave signs are not obvious. At the same time, it is accompanied by weakness, weak limb tension and cold limbs, and prolonged capillary filling time of the heel.
Differential diagnosis
When examining the presence or absence of bruising in newborns, it is necessary to correctly distinguish between peripheral cyanosis and central cyanosis, lips and oral mucosa, which is the most reliable and sensitive part of true cyanosis. The obvious local cyanosis is still needed in some newborns. Skin pigmentation, such as the difference between the birth and the birth of the baby, the common skin pattern is often seen in the newborn, more obvious in the cold environment, due to the autoregulation instability of the skin vasomotor, the baby exposed on the face is exposed to the head and face due to stress Caused by congestion, edema, local skin and even lips can be blue-purple, should be distinguished from central cyanosis.
1. Identification of congenital heart disease: severe cyanosis in newborns should be examined in detail for congenital heart disease, many congenital cyanotic heart disease symptoms in the neonatal period, such as tetralogy of Fallot, pulmonary stenosis Or atresia, tricuspid atresia or insufficiency, large vessel displacement, total arterial trunk, left ventricular dysplasia syndrome, etc., it should be noted that some cyanotic congenital heart disease in the neonatal period may sometimes not show cyanosis, such as faro In the neonatal period, due to the opening of the arterial catheter in the neonatal period, there is no significant decrease in blood entering the pulmonary circulation. Cyanosis does not occur. The total arterial trunk is not hardened due to the small pulmonary artery in the neonatal period. The pulmonary circulation pressure is low, and a large amount of blood can enter the lungs. Inside, at this time, cyanosis is very light or has no obvious cyanosis. On the contrary, some non-cyanotic heart disease may sometimes appear cyanosis in the neonatal period. For example, ventricular septal defect, when certain factors increase pulmonary artery pressure, exceed the aortic pressure, right ventricle The pressure is greater than the left ventricular pressure, and the right to left shunt through the defect port causes the baby to produce cyanosis.
When cyanosis is accompanied by heart murmur, heart enlargement or heart failure, the diagnosis of congenital heart disease can be clearly established, but cyanosis can sometimes exist alone, and some extremely serious cyanotic congenital heart disease does not appear in the neonatal period. Noise, such as complete vascular transposition and pulmonary valve atresia, without other cardiac malformations, can not hear murmurs or loud murmurs.
On the other hand, hearing heart murmurs in the neonatal period is not necessarily congenital heart disease. Infants with severe asphyxia resuscitation, tricuspid regurgitation due to hypoxic injury of the papillary muscles, under the xiphoid or left sternal border 3 4 intercostal can hear loud systolic murmur. At this time, if accompanied by pulmonary hypertension, the right or left shunt of the catheter level or atrial level is generated, forming a continuous fetal circulation, and the baby is severely cyanotic, which is a need and congenital Clinical syndrome that distinguishes heart disease.
2. Identification of pulmonary source cyanosis and cardiogenic cyanosis: It is generally believed that cyanosis disappears after inhaling pure oxygen, and this cyanosis is caused by lung diseases. If it does not disappear, it is cardiogenic cyanosis, but it is not entirely true, such as:
(1) Neonatal lung disease: pulmonary diseases, especially hyaline membrane disease, often produce a right-to-left shunt in the lungs or through the foramen ovale during the course of the disease, and severe cyanosis occurs. At this time, inhalation of pure oxygen does not increase PO2. Reduce or disappear the bruising.
(2) Open arterial catheter: open arterial catheter can cause cyanosis due to pulmonary failure and small airway obstruction. After inhalation of pure oxygen, cyanosis can disappear. This is because the arterial catheter is open but heart disease, but hypoxia. The mechanism of blood production is insufficient alveolar ventilation.
(3) Large blood vessel translocation: infants have severe cyanosis when inhaling indoor air. After inhaling pure oxygen, cyanosis can be alleviated. The mechanism is to reduce pulmonary vascular resistance after inhaling pure oxygen and increase arteriovenous blood through the foramen ovale or artery. The shunt of the catheter, the arteriovenous blood can be better mixed, and the infant cyanosis can be slightly relieved. Therefore, the response to inhaled pure oxygen can only be considered as the pathophysiological mechanism of the disease and the severity of the lesion. It is not certain that the lesion causing cyanosis is Cardiogenic or pulmonary.
In general, after inhaling pure oxygen, such as PaO2 rising above 33.25 kPa (250 mmHg), the right to left shunt caused by any cause can be excluded.
When cyanosis is caused by right to left shunt, to distinguish between right and left shunt is pulmonary or cardiogenic, can be differentiated by intravenous pulmonary vasodilator, usually with torazoline or phentolamine to dilate the lungs Blood vessels, reduce pulmonary artery pressure, the dose is 0.5 ~ 1.0mg / time, injected through the scalp vein in 20min, if it can be directly injected into the pulmonary artery, the effect is better, if the pulmonary vascular resistance is reduced after the injection, Pa02 is obviously increased, and the bruising is reduced or disappeared. The heart structure is normal, and this right to left shunt may be caused by lung lesions or pulmonary vascular disease.
3. Identification of methemoglobinemia: neonates are more prone to methemoglobinemia than infants and children. This is because neonatal blood contains more fetal hemoglobin, which is more likely to form methemoglobin than adult hemoglobin, when methemoglobin concentration When 15g/L (1.5g/dl), the blood is dark brown, the skin and mucous membrane appear bruising, and there are three causes of neonatal methemoglobinemia:
(1) HbM disease: less common, is a hereditary hereditary abnormal hemoglobin leukemia, has a clear family history, bruising often persists, a small number of intermittent episodes, any treatment is ineffective.
(2) Temporary NADH methemoglobin reductase deficiency: no family history, moderate cyanosis, no hypoxic symptoms, cyanosis can be gradually reduced after neonatal period.
(3) methemoglobinemia caused by poisoning or drugs: It has been reported that neonatal methemoglobinemia is caused by well water-filled milk powder containing nitrate or nitrite, and the drug causing methemoglobinemia is sulfonamide. Class, antimalarial, antipyrine, vitamin K1 and phenacetin, etc., the blood of methemoglobinemia is dark brown, does not turn red after mixing with air, according to this point can be caused by other reasons Cyanosis difference, methemoglobinemia caused by drugs or poisoning, after intravenous injection of methylene blue or vitamin C, bruising is reduced or disappeared, and congenital methemoglobinemia does not respond to this treatment.
