Neonatal cyanosis

Introduction Cyanosis, also known as purpura and cyanosis, is the expression of reduced hemoglobin 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 richer, such as the lips, the tip of the toes, and the earlobe. Hair blemishes can be caused by insufficient airway disease in the lungs, and are 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. The disease is mainly based on prevention, and strengthening perinatal care is an important means to prevent this disease.

Cause

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 yet, and the right to left shunt remains, and the lung has not fully expanded, and the lung ventilation function is imperfect, and The circulatory system changes after 5 minutes of poor perfusion of the surrounding skin, the arteriovenous blood flow was completely separated, and the lips and nail bed became pink. However, sometimes the skin is still mildly cyanotic, especially after exposure to cold environment. The local blood flow at the distal end of the limb is slow and the hemoglobin is increased. Therefore, although the PaO2 is not low, the extremity is still obviously cyan, which is called the surrounding cyanosis. After bruising can be reduced or disappeared.

(2) Temporary bruising: Normal newborns may appear cyanosis when crying hard because the intrathoracic pressure increases when crying, so that the right atrial pressure rises above the left atrial pressure, forming a right-to-left shunt through the oval hole. This temporary bruising disappeared immediately after the crying stopped.

2. Central cyanosis: caused by a decrease in arterial SO2 and PaO2 by cardiopulmonary disease. According to the cause can be divided into pulmonary and cardiogenic.

(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 diaphragmatic congenital pulmonary arteriovenous, continuous fetal circulation, etc.

(2) Cardiac cyanosis: Congenital heart disease with right-to-left shunt is more common in the neonatal period with tetralogy of Fallot, large vascular translocation left ventricular dysplasia syndrome, pulmonary venous venous return artery Dry, tricuspid atresia, and severe pulmonary stenosis.

3. Peripheral bruising: Because the blood flows through the surrounding circulatory capillaries, the blood flow rate is slow and 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 in heart failure, decreased cardiac output during shock, peripheral blood supply, reduced blood viscosity in capillary blood stasis, erythrocytosis, hard swelling, low body temperature, blood Decreased cardiac output can cause the blood flow to slow down and appear cyanosis.

(2) local blood flow disorder: the first exposed part of the childbirth, such as the face and hips, can appear cyanosis, in addition to neonatal physiological conditions, the limbs can also appear cyanosis.

Others such as central nervous system disorders caused by respiratory failure, hypoglycemia, secondary apnea caused by hypocalcemia, abnormal hemoglobin, such as hereditary methemoglobinemia, acquired methemoglobinemia, M-hemoglobinemia Etc., can cause cyanosis.

an examination

Related inspection

Toxoplasma antibody anti-platelet antibody anti-platelet antibody (APA) amniotic fluid bilirubin amniotic fluid bilirubin

If you want to confirm whether there is any cyanosis in the clinic, you should immediately do blood gas analysis and determine the central cyanosis by PaO2. You should find the reason as soon as possible to correct hypoxemia in time to avoid the disease.

The respiratory rate, depth, presence or absence of inspiratory depression and expiratory sputum should be carefully examined, and the nose flaps should be used, and X-ray films should be taken. Generally mild cyanosis with obvious three concave signs, suggesting that the lung lesions; severe cyanosis with mild three concave signs, mostly congenital heart disease; cyanosis without any breathing difficulties more consistent with methemoglobinemia; caused by craniocerebral diseases The bruising often has superficial breathing, irregular rhythm, and even apnea; bruising caused by sepsis, shock, shallow and fast breathing, and the three concave signs are not obvious, accompanied by weakness of the limbs and low limbs, heel The skin capillary refilling time is prolonged.

Laboratory inspection:

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 may 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, the blood is dark brown when the methemoglobin concentration is 15g/L (1.5g/dl), and the skin and mucous membranes appear cyanotic.

Other auxiliary inspections:

1. X-ray chest radiograph: to determine whether there is cardiopulmonary disease such as congenital heart disease, congenital esophageal atresia (with tracheal fistula), congenital diaphragmatic nerve injury, neonatal pneumothorax, neonatal atelectasis, neonatal pneumonia And so on have the corresponding X-ray performance characteristics.

2. Others: According to the condition, choose B-ultrasound, ECG CT, etc. If the suspected neonatal intracranial hemorrhage can be used for CT scan of the brain, to confirm the diagnosis.

Differential diagnosis

Determining the diagnosis requires analysis of ECG and echocardiography and other necessary examinations based on clinical observations, X-ray chest radiographs, and other necessary tests to determine whether there is a cardiopulmonary disease.

When examining the presence or absence of bruising in newborns, it is necessary to correctly distinguish between peripheral cyanosis and central cyanosis. The lips and oral mucosa are the most reliable and sensitive parts that reflect the true cyanosis. The obvious local cyanosis is still needed in certain newborns. Pigment coloration, 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 auto-regulation instability of the skin vasomotor contraction, the baby exposed on the face and face can be seen in the head and face due to pressure The congestion, edema, local skin and even the lips can be blue-purple and 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 manifests symptoms in the neonatal period, such as tetralogy of Fallot pulmonary artery stenosis or Atresia, tricuspid atresia or insufficiency, large vessel displacement, total arterial trunk left dysplasia syndrome, etc., should be noted that some cyanotic congenital heart disease in the neonatal period may not show cyanosis, such as Faro IV In the neonatal period, due to the opening of the arterial catheter, the blood entering the pulmonary circulation does not appear to reduce cyanosis. Total arterial trunk due to the small pulmonary artery in the neonatal period has not yet hardened. The pulmonary circulation pressure is low, and a large amount of blood can enter the lungs. At this time, the bruising is very light or has no obvious cyanosis. On the contrary, some non-cyanotic heart diseases can sometimes be in the neonatal period. Cyanosis, such as ventricular septal defect When certain factors increase pulmonary artery pressure beyond aortic pressure, right ventricular pressure is greater than left ventricular pressure through the right to left shunt of the defect port to cause cyanosis in the baby.

The diagnosis of congenital heart disease can be clearly established when cyanosis is accompanied by heart murmur enlargement or heart failure. However, cyanosis can sometimes exist alone. Some extremely serious cyanotic congenital heart diseases do not have murmurs in the neonatal period, such as complete vascular transposition and pulmonary valve atresia. If you do not combine other cardiac malformations, you will not hear them. Noise or no loud noise.

On the other hand, hearing heart murmurs during the neonatal period is not necessarily congenital heart disease. In infants with severe asphyxia resuscitation, the tricuspid regurgitation is caused by hypoxic injury of the papillary muscles. Loud systolic murmurs can be heard under the xiphoid or 3 to 4 intercostals of the left sternal border. At this time, pulmonary hypertension is accompanied. A right-to-left shunt that produces a catheter level or atrial level, which forms a continuous fetal circulation, and a baby with severe cyanosis is a clinical syndrome that needs to be distinguished from congenital heart disease.

2. Identification of pulmonary source cyanosis and cardiogenic cyanosis: It is generally believed that cyanosis is caused by lung disease after inhalation of pure oxygen. This cyanosis is caused by lung disease. If it does not disappear, it is cardiogenic cyanosis but not completely, such as:

(1) Neonatal lung disease: pulmonary diseases, especially hyaline membrane disease, often produce right-to-left shunts in the lungs or through the foramen ovale during the course of the disease, and severe cyanosis occurs when inhaling pure oxygen does not increase PO2. Cyan is reduced or disappeared.

(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, a right-to-left shunt caused by any cause, such as a PaO2 rise above 33.25 kPa (250 mmHg) after inhalation of pure oxygen.

When cyanosis is caused by a right-to-left shunt, it is a distinction between a right-to-left shunt that is a pulmonary-derived or cardiogenic intravenous vasodilator. Usually, the lung vessels are dilated with tolazoline or phentolamine, and the pulmonary artery pressure is reduced to 0.5-1.0 mg/time. The scalp vein is injected at 20 minutes. If it is directly injected into the pulmonary artery, the effect is better. After injection, if the pulmonary vascular resistance is reduced, Pa02 is significantly increased, and the reduction or disappearance of cyanosis suggests that the heart structure is normal. This right to left shunt may be caused by pulmonary lesions or pulmonary vascular disease.

3. Identification of methemoglobinemia: Newborns 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 the concentration of methemoglobin is 15g/L (1.5g/dl), the blood is dark brown, and there are three causes of methemoglobinemia in the skin and mucous membranes.

(1) HbM disease: less common for dominant hereditary abnormalities. Hemoglobin leukemia has a clear family history. Cyanosis is often persistent, and a small number of intermittent episodes of any treatment are ineffective.

(2) Temporary NADH methemoglobin reductase deficiency: no family history, moderate cyanosis without 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 causes Sexual cyanosis, methemoglobinemia caused by drugs or poisoning, cyanosis is reduced or disappeared after intravenous injection of methylene blue or vitamin C. Congenital methemoglobinemia does not respond to this treatment.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.