Air embolism

Air embolism (VE) occurs due to ingress of air into the vessels of the lungs or a large circle of blood circulation (paradoxical embolism).

Since the first half of the XIX century, in the literature periodically met descriptions of air embolism in obstetrics. The expansion of diagnostic capabilities (precardial dopplerometry, echocardiography, end-expiratory gas analysis) made it possible to more accurately estimate the frequency of RE in obstetrics. It is found during caesarean section under general anesthesia of 52-71%, with regional anesthesia - in 39% of cases. Approximately with the same frequency (10-37%), there are signs of RE with spontaneous childbirth. Clinical manifestations are noted only in 0.78% of cases.

ICD-10 code

088.0. Obstetric air embolism.

Causes Air embolism

Causes of air embolism

Factors contributing to the development of VE in obstetrics:

• deviation of the uterus to the left and its excretion into the cavity of the wound with caesarean section (increases the pressure gradient),
• the position of Trendelenburg,
• rotation and increment of the placenta,
• placenta previa,
• decreased CVP (with bleeding or shortage of BCC in severe gestosis),
• use of nitrous oxide in general anesthesia.

Air embolism is possible in the following clinical situations by caesarean section, premature detachment of the normally located placenta, manual placental separation, instrumental scraping of the uterus, hysteroscopy, manipulation of the central venous catheter. And also air embolism arises at the gaping of venous vessels and when between the operative wound and the right atrium the gravitational gradient is 5 cm of water. Art.

Pathogenetic mechanisms that lead to disruption of cardiac activity and respiration are similar to those in PE.

Severity of manifestations and mortality in air embolism depend on the volume, rate of air intake, and localization of the air embolus. Air volumes of more than 3 ml / kg can lead to a fatal occlusion of blood flow from the right ventricle ("air lock"). Smaller amounts of air contribute to the violation of ventilation-perfusion relationships and are manifested by hypoxemia, overload of the right heart, arrhythmia, hypotension. The ingress of air into the system of arterial circulation through an open oval hole may manifest as acute coronary insufficiency and neurologic symptoms. At a high intake rate, air can pass into a large circulation and through the pulmonary vessels.

[1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15]

Symptoms Air embolism

Symptoms of air embolism

Symptoms of massive air embolism are chest pain, cyanosis, cervical veins, dyspnea (more often respiration by the type of gasping), brady or tachycardia, arterial hypotension, heart rhythm disturbances. In severe EV, bronchospasm, AL, circulatory arrest are possible. With paradoxical embolism - coronary or neurological symptoms. Auscultatory it is possible to find "drum" tones of the heart, which replaces the noise of the "mill wheel", caused by the mixing of blood and air in the right ventricle.

Diagnostics Air embolism

Diagnosis of air embolism

With the help of instrumental diagnostic methods, one discovers:

• increased CVP and pressure in the pulmonary artery due to congestion of the right heart,
• a decrease in the level of CO2 at the end of expiration during capnography,
• reduction of saturation,
• hypoxemia,
• moderate hypercapnia,
• on ECG signs of congestion of the right heart - changes in the tooth P, depression of the ST segment,
• Pre-cardiac dopplerometry and echocardiography - air in the heart cavity.

To diagnose paradoxical embolism, a CT scan or magnetic resonance imaging of the brain or spinal cord is performed.

[16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26]

Treatment Air embolism

Treatment of air embolism

• Stop further air intake (surgical hemostasis, irrigation of the operating field with saline solution, change in body position).
• Give the operating table a slant to the left and lower the head end to displace the "air lock" and "lock" it in the right atrium or ventricle.
• With spontaneous breathing, begin inhalation of 100% oxygen, switch to mechanical ventilation if necessary.
• With general anesthesia, stop the supply of dinitrogen oxide and run the ventilator with FiO ₂ 21.0.
• Stabilize hemodynamics (infusion therapy and vasopressors to eliminate hypotension).
• Try to aspirate air from the central vein, the chambers of the heart through a catheter located 1 cm below the site of the inferior vena cava into the right atrium.
• Accelerate delivery.
• When migrating an air embol into the brain - HBO.
• When the circulation stops, CPR.