Aortocaval Compression Syndrome - Causes, Symptoms, and Treatment

What Is Aortocaval Compression Syndrome?

Aortocaval compression syndrome is typically seen in pregnant women, usually after 20 weeks of gestation and mainly in a supine position. It is also known as a supine hypotensive syndrome. In this condition, the blood flow from the lower extremities back to the heart and central circulation is affected due to the uterus compressing on the inferior vena cava artery aorta. This restricts the blood flow to the placenta and results in mortality and morbidity of the fetus and mother. Not being diagnosed and treated at the right time can lead to hypotension in pregnant women and many serious complications.

What Is the Cause of Aortocaval Compression Syndrome?

The curvature of the lumbar spine leads to outward bowing of the vertebral column and the lower spine toward the abdominopelvic cavity. During pregnancy, the uterus is located intra-abdominally near the l4 l5 level. The uterus compresses the inferior vena cava and the aorta artery. In cases of the supine position, this worsens, and gravity allows the uterus to rest posteriorly to the lordotic spine compressing the inferior vena cava by the weight of the uterus. This affects the blood flow returning from the extremities to the heart resulting in maternal hypotension.

Due to any type of trauma or accidental injury, the pregnancy may lead to complications. This syndrome can also occur as a result of trauma. Mostly occurs in gestational age greater than 20 weeks, but it can also occur soon in certain conditions.

What Happens in Aortocaval Compression Syndrome?

Normally the uterus, in a non-pregnancy state, has a blood flow of 60 millimeters per minute. In pregnancy, the uterus's blood increases ten times more, and the vascular dynamics also increase. Even a mild decrease in blood return may lead to negative effects on the fetus and maternal health. This condition is initially experienced by initial tachycardia and late bradycardia. Symptoms like:

• Pallor (anemic).

• Nausea.

• Hypotension.

• Dizziness.

• Diaphoresis (sweating, especially in unusual degrees).

Most of the symptoms are involved with an impedance of blood flow. The change of position may relieve symptoms mostly when the position is changed by turning or lying on the side. This relieves the compressing pressure of the gravid uterus on the vena cava.

How Is the Syndrome Evaluated?

The aortocaval compression syndrome is normally evaluated clinically. A normal ultrasound is used to evaluate the syndrome. This can be helpful.

What Is the Treatment of Aortocaval Compression Syndrome?

The first line of treatment of aortocaval compression syndrome is treating hypotension, which is then followed by physical movement of the uterus of the spine and inferior vena cava, and this is very necessary. For this, many ways are tried when trauma is not involved in the case; simply placing the individual's left lateral position is done. And when trauma is present, immobilization of the spine is done, and different maneuvers are indicated.

A unique challenge is presented in individuals with cervical spine immobilization.

Three ways can be used to accomplish it. They are:

1. Isolate elevation of the right hip alone may alleviate compression. Also, tilting backward by 15 to 30 degrees to the left is an additional benefit.

2. This technique is either done with elevators like premade elevators or manually by placing towel rolls under the board.

3. It is tough sometimes as the weight of the gravid abdomen is more and gravity pulls the individual's left side, compromising spinal immobilization. In-line mobilization is a priority though it is difficult.

4. When the prior mentioned, both maneuvers are not options due to any moribund condition, and CPR (Cardiopulmonary resuscitation), a manual displacement of the uterus to the left of the midline, is used as a treatment option. During this, the provider's hand is placed on the right side of the abdomen and lateral to the gravid uterus and shifts the uterus to the left. This releases the pressure on the vena cava. It requires no expertise, a simple, less harmful procedure to the fetus and uterus.

What Are the Complications and Special Considerations With Aortocaval Compression Syndrome?

The complications and special considerations with aortocaval compression syndrome are:

• Aortoocaval compression is not confined to ladies at term. It can also be reported during the fifth month of pregnancy. Hydraminos or multiple pregnancies can also increase the risk of getting the condition.

• Normal blood pressure and lack of maternal symptoms should be appreciated, and significant cardiac output and placental perfusion should not be excluded.

• Most times, symptoms occur within 30 seconds or may be delayed by 30 minutes.

• Severity is based on the severity of hypotension.

• Conditions like catastrophic hypotension and cardiac arrest can occur if the woman with aortocaval compression is induced with general anesthesia.

What Is the Differential Diagnosis of Aortocaval Compression Syndrome?

The differential diagnosis of aortocaval compression syndrome is

• Stridor - Abnormal high-pitched musical breathing sound.

• Tracheomalacia - Condition in which cartilage in the trachea and windpipe has not developed properly.

• Thoracic Outlet Syndrome- A condition in which muscles, nerves, and vessels in between the rib and collar bone gets compressed.

• Pancreatitis- Inflammation of the pancreas.

• Laryngomalacia- A condition that leads to a common cause of noisy breathing in infants.

• Myocarditis- Inflammation of the myocardium.

• Cardiac Tamponade- A condition that leads to increased pressure in the heart due to fluid and blood buildup in space between the outer covering sac and the heart muscle.

• Hemorrhagic Shock- Condition in which severe shock leads to severe blood loss and inadequate oxygen delivery.

• Cardiogenic Shock- A condition where the heart fails to pump enough blood.

• Peripheral Vascular Injuries- Injuries of the extremities.

• Pediatric Subglottic Stenosis Surgery- Narrowing of the subglottis.

• Mechanical Back Pain- Back pain due to spinal stenosis, zygapophysial joint pain, herniated disc, and myofascial pain.

• Bronchiolitis- Lung infection in infants and children.

• Aortic Intramural Hematoma- Life threatening condition in which the acute aortic syndrome includes aortic penetrating ulcer and aortic dissection.

• Aortic Regurgitation- Condition in which the aortic valve does not close properly.

Conclusion:

It is very difficult to diagnose aortocaval syndrome, and it is best performed by an interprofessional team, including an internist, obstetrician, radiologist, nurse practitioner, intensivist, and emergency department physician. Once the diagnosis is made, the main focus is to relieve the pressure on the vena cava. Depending on the position, because the treatment is provided to improve the symptoms, the individual is warned that the signs and symptoms can be worse in a supine position, and a change of position is required immediately to ease the symptoms.