Anaphylactoid response to Optison® and its effects on pulmonary function in two dogs

Two of 26 anesthetized dogs given the cardiac echo-enhancing agent Optison® showed anaphylactoid responses (AR) related to the human albumin component of this agent. The episodes of AR were self-limited, and could be reproduced by human albumin injection alone. Gas exchange was maintained by mechanical ventilation and 5 cm H₂O PEEP, and dispersion of ventilation remained normal during AR despite severe hypotension. We suggest that: (1) pre-screening by measuring blood pressure response to intravenous injection of small doses of Optison®, and (2) availability of access to the airway in addition to emergency agents may be prudent preventive measures when Optison® is used in animals to enhance echocardiographic imaging.