To the Editor: - Venous air embolism has been reported during neurologic and cardiothoracic procedures, but only one report describes it during arthroscopy. We report an additional case that occurred during shoulder arthroscopy.
A 40-yr-old healthy woman was scheduled for arthroscopy of the left shoulder. There was no history of allergy or reactive airway disease. She was administered general anesthesia with sevoflurane/nitric oxide/oxygen after placement of an interscaline block. Ventilation was controlled. The patient was placed in the beach-chair position. After the skin incision was made, the surgeon injected 60 ml air into the joint, after which the arthroscope was inserted. This was followed by the infusion of saline into the joint. Within 3 min after the insertion of the arthroscope, the end-tidal carbon dioxide (ETCO2) decreased to less than 10 mmHg. The oxygen saturation by pulse oximetry (SpO2) decreased to less than 90% before the signal acquisition was lost. Blood pressure measurement was unobtainable. The electrocardiogram showed a sinus rhythm at 90 beats/min. Anesthetics were discontinued, manual ventilation with 100% oxygen was begun, surgery was discontinued, and the patient was placed in the supine position. No pulse was felt in the groin or the neck, and closed chest massage was begun. At the same time, 1 mg intravenous epinephrine was administered. After approximately 3 min, spontaneous pulses were palpated. A radial artery catheter was placed, revealing a pressure of 160/100 mmHg. Oxygen saturation remained below 90%, but the capnogram returned to normal height with an end-expiratory value of 34 mmHg. The oxygen saturation gradually rose to the low 90% range. An arterial blood gas sample showed a pH of 7.25, a PO2of 64 mm Hg, a PCO2of 48 mmHg, and a base deficit of -6. The patient was transferred to the intensive care unit. Serial cardiac enzymes did not reveal myocardial infarction. Subsequent chest radiography was consistent with mild pulmonary edema and elevated right hemidiaphragm, but not pneumothorax. The patient was extubated the next day and discharged from hospital in good condition on the second postoperative day.
When cardiopulmonary resuscitation was begun, we were not aware of the insufflation of air because it was used for the first time by this surgeon. Later, we learned that 60 ml air had been injected followed by a jet stream of crystalloid solution.
The Australian Incident Monitoring Study (AIMS) reported the overall incidence of detectable venous air embolism in 2000 incidents to be 1%. The surgical field was the entry field in 63% of cases, 47% occurred during head and neck surgery. The incidence of venous air embolism is increased to 15% when the patient is in the sitting position, as in neurosurgical procedures and forceful insufflation of air into the operating field. Slow infusion of air or small amounts of air might be undetected in the anesthetized patient and may occur more often than reported. By control, the rapid changes seen in our patient suggested the injection of air over a short period. In our patient, the disappearance of the end expired carbon dioxide wave was most useful, not only for early detection, but also for confirmation of the diagnosis. Although the incident of venous air embolism during arthroscopy is rare, the possibility has to be kept in mind.
Eveline A. M. Faure, M.D.
Associate Professor of Anesthesia and Critical Care
Richard I. Cook, M.D.
Assistant Professor of Anesthesia and Critical Care
David Miles, C.R.N.A.
Department of Anesthesia and Critical Care; University of Chicago; Chicago, Illinois; firstname.lastname@example.org
(Accepted for publication May 12, 1998.)