Venous air embolism is a potential surgical complication when a negative pressure gradient exists between the surgical site and the right atrium of the heart. It occurs more commonly when the operative site is over the heart, the pressure of gas in the body cavity exceeds that of the venous sinusoids (15 to 30 mm Hg), air rather than carbon dioxide is injected, or the venous sinusoids of bone marrow are exposed1,2. Shoulder arthroscopy satisfies many of these criteria: the beach-chair and lateral decubitus positions place the surgical site over the right atrium, the standard settings for arthroscopic pumps are at pressures of >30 mm Hg, air bubbles are often observed entering the joint, and venous sinusoids are exposed anytime that osseous work (i.e., distal clavicular excision, acromioplasty, or fracture repair) is performed. Two case reports of fatal venous air embolism following knee arthroscopy3,4 with intentional air insufflation have appeared in the literature, but we are not aware of any reported case following liquid-only arthroscopy.
We present the case of a patient undergoing revision arthroscopic rotator cuff repair and distal clavicular excision who experienced acute intraoperative cardiopulmonary collapse and was resuscitated, but died on postoperative day 14. The patient was undergoing liquid-only arthroscopy, and we postulated that air entered the joint through an unrecognizedair reservoir: commercially available 3-L arthroscopic fluid bags.
A forty-seven-year-old woman presented with a six-month history of severe pain in the right shoulder. The history, physical examination, and magnetic resonance imaging revealed a small, full-thickness tear of the supraspinatus tendon. After the failure of six months of conservative treatment, she elected to undergo arthroscopic supraspinatus repair and subacromial decompression. Unfortunately, four months postoperatively, while she was at work, a box of equipment fell from a shelf, striking her on the head and shoulder. Physical examination in conjunction with a magnetic resonance arthrogram revealed tenderness over the acromioclavicular joint and a full-thickness rerupture of the supraspinatus tendon. The patient failed to respond to an additional six months of conservative treatment, and ten months following the previous procedure she elected to undergo a revision arthroscopic rotator cuff repair and distal clavicular excision.
Preoperatively, she was evaluated and cleared medically for surgery by an internist. The only notable findings in her medical history were anemia and hypertension. She had no family history of anesthesia-related events.
She underwent a liquid-only revision arthroscopic rotator cuff repair with a distal clavicular excision in the beach-chair position. A closed-system arthroscopic pump was utilized without a continuous outflow. Following a standard diagnostic arthroscopy, which confirmed the existence of a rotator cuff tear, 8 to 10 mm of the clavicle was excised with use of standard arthroscopic techniques. Immediately following the distal clavicular excision, a sudden influx of air into the shoulder was observed in conjunction with the two 3-L arthroscopic fluid bags running dry. Although the inflow was disconnected in an attempt to limit the amount of incoming air, it could not be done before a substantial amount of air had entered the subacromial space. On replacement of the bags, the procedure continued and attention was turned to the torn rotator cuff.
Moments later, the anesthesia alarm indicated a severe decrease in end tidal carbon dioxide (CO2). A simultaneous decrease in blood pressure and heart rate was also observed. The patient became progressively unstable. Therefore, the arthroscopic wounds were closed rapidly, and the case was aborted to allow the anesthesiologists and additional staff to stabilize the patient. Over approximately the next fifteen minutes, the patient was stabilized as indicated by a stable heart rate and blood pressure and increasing end tidal CO2.
A transesophageal echocardiogram demonstrated a dilated, hypokinetic right ventricle. The echocardiogram ruled out a large thrombotic embolism in the right side of the heart and pulmonary arterial system. No atrial septal defect was observed. However, during the echocardiogram, small air bubbles were observed passing through the right side of the heart. A moderate to severe decrease in right ventricle contractility was seen. A subsequent multidetector computed tomography angiogram was negative for a thrombotic embolism.
The patient was transferred to the intensive care unit for ventilatory and medical support. She exhibited findings consistent with anoxic brain injury, including persistent myoclonic activity, fixed and dilated pupils, and unresponsiveness to painful stimuli. Computed tomography scans of the brain revealed progressive cerebral edema with bilateral patchy infarcts. An electroencephalogram demonstrated seizure activity not associated with the myoclonus. The patient died on postoperative day 14, and the family declined an autopsy.