乌鸦传媒

What to do for a woman in her mid-20s who presented with shortness of breath on exertion that had been bothering her for the past 2 years? That's what Praveen Gupta, DM, of the Praveen Heart Clinic and Research Foundation in New Delhi, needed to determine.

On physical examination, the woman's pulse was 70 beats per minute, and blood pressure was 110/70 mm Hg. "The cardiovascular examination showed a loud S1, normal S2, and an opening snap along with a mid-diastolic, soft, rumbling murmur at the apex of the heart," Gupta reported in a case study.

Clinicians performed an ECG, which showed that the patient's sinus rhythm was normal and the left atrium was enlarged. They detected significant stenosis of the mitral valve, with an area of 0.9 cm² and a mean gradient of 20 mm Hg.

The ECG also showed no signs of thickening below the mitral valve, and there was no evidence of leaflet calcification or mitral regurgitation. The patient was referred for a balloon mitral valvotomy (BMV).

Surgeons accessed the left ventricle via the right femoral artery to place a 6F pigtail catheter. They punctured the interatrial septum using a Mullins sheath and Brockenbrough needle, accessed via the right femoral vein.

"Entry into the left atrium was made and confirmed with a dye injection," Gupta wrote. At this point, the patient suddenly experienced an acute episode of dyspnea and chest pain behind her sternum.

When this event occurred, her blood pressure was 100/60 mm Hg, pulse was 70 beats per minute, and oxygen saturation was 96%. Clinicians pulled the catheter back into the right atrium, and immediately performed chest fluoroscopy, which revealed "a pulsatile translucency in the main pulmonary artery."

The opacity was similar in shape to the trunk of the main pulmonary artery, and alternating expansion and contraction with the cardiac cycle was noted. "The opening and closing of the pulmonary valve were visible at the inferior part of the translucent shadow," Gupta wrote. The patient was diagnosed with a large air embolism located in her main pulmonary artery.

The BMV procedure was stopped, and the patient was placed in the Trendelenburg position and was administered intravenous fluids and 100% oxygen. Clinicians had planned to remove the air embolus in the main pulmonary artery using a Judkins right coronary catheter, but "it was absorbed within 3 to 4 minutes with the medical management alone." The patient had a quick recovery. When she was stable, she was released from the hospital and advised to return 1 month later to undergo the BMV.

Discussion

Gupta noted that that pericardial tamponade resulting in pericardial effusion is a rare complication of BMV. Low blood pressure accompanies acute tamponade, and tamponade is characterized on fluoroscopy by reduced movement of cardiac borders, "along with separation of visceral and parietal pericardium due to accumulation of blood, which was not present in this case. Hence, pericardiocentesis was not indicated."

Gupta explained that a sudden development of a large thromboembolism in the main pulmonary artery generally causes an acute fall in blood pressure and shortness of breath, while findings of fluoroscopy tend to be unremarkable.

In rare cases of pulmonary embolism, fluoroscopy findings may include "a prominent pulmonary artery, an enlarged right descending pulmonary artery (Palla sign), an abrupt cutoff of vessels, elevated hemidiaphragm along with focal pulmonary oligemia (Westermark sign), and peripheral, pleural-based, wedge-shaped opacity (Hampton hump) due to pulmonary infarction," Gupta wrote.

On the other hand, contrast angiography will show an acute pulmonary embolism as a filling defect. Given the absence of any of these characteristic features in this patient, there was no indication for intravenous thrombolytic and catheter-directed removal of the air embolism.

A massive pulmonary artery air embolism can occur during , Gupta noted. However, air embolism has been seen more commonly in the presence of the following risk factors:

• Dehydration
• Low central venous pressure
• Coughing
• Deep inspiration
• Old age
• Use of a large central venous sheath
• Deep sedation

Depending on its size, an air embolism can cause no symptoms at all, or can result in a life-threatening fall in blood pressure requiring immediate cardiopulmonary resuscitation. Treatments include administration of 100% oxygen and intravenous fluids, as well as inotropic agents and cardiopulmonary resuscitation as required to stabilize circulation and optimize oxygen supply.

While this patient was placed in the Trendelenburg position, Gupta cited a recent report that said that the use of the Durant maneuver, in which the patient is placed in a left lateral decubitus position, is the preferable approach to managing a patient with air embolism. Very rarely, a has been used to suction the air from the pulmonary artery.

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