Suspected air embolism associated with post-anesthetic pulmonary edema and neurologic sequelae in a horse.

A Quarter Horse underwent anesthesia for eye removal surgery, and during recovery a cap was dislodged from a jugular vein catheter which resulted in lung congestion due to leakage of fluid into lung tissues (pulmonary edema) and oxygen deficiency in the blood (arterial hypoxemia). Despite resolving lung congestion, the horse exhibited an impaired sense of balance and loss of vision, indicating some neurological impacts. After a week-long treatment that included different types of medicine and oxygen supply via the nose, the horse gradually recovered and was free of neurological symptoms in six weeks. Although an air bubble blocking blood supply (air embolism) was not officially confirmed in this case, the sequence of events hints at the catheter cap incident being the underlying cause of the lung and neurological complications.

Overview of the Case

• The patient was a 523 kg Quarter Horse who was put under anesthesia for the surgical removal of an eye (unilateral eye enucleation).
• During the animal’s recovery, the cap on a catheter inserted into the jugular vein became dislodged, which presumably allowed air to enter the bloodstream.
• Following this, the horse developed pulmonary edema (fluid build-up in the lungs) that was associated with moderate arterial hypoxemia (low blood oxygen levels).

Post-Anesthetic Complications

• Though the lung congestion resolved following medical treatment, neurological symptoms manifested the next day. These symptoms included vestibular disease (a condition related to the balance system causing issues like dizziness and loss of balance) and blindness.
• The treatment regimen, which lasted 7 days, comprised insufflating oxygen into the nostrils, administering analgesics, diuretics, steroids, vitamins, antimicrobials and supplying compounds with anti-inflammatory properties.
• After the week-long hospital stay, the horse was discharged.

Follow-up and Prognosis

• Six weeks post-discharge, the horse was examined and found to be neurologically normal.
• Although air embolism was not confirmed in this particular case, the evidence i.e., the dislodged catheter cap followed by lung and neurological complications, supports it as the presumable cause.
• This case report suggests that echocardiography (an ultrasound imaging technique to visualize the heart’s internal structure) should be used for the definitive diagnosis of air embolism in horses showing similar acute clinical symptoms.