Abstract
Abstract Confirmation bias is an ever‐present risk to the rapid decision‐making required in emergency departments (EDs). We present a case of a young woman who was brought to ED by ambulance with hypotension, syncope and vaginal bleeding, with a presumptive pre‐hospital diagnosis of ruptured ectopic pregnancy. On arrival in ED, she was found to have intra‐abdominal free fluid on bedside ultrasound. This finding could have been used by clinicians to confirm their suspicion of a ruptured ectopic; however, with further investigations, it was found that anaphylaxis was the most likely cause of the patient's symptoms. This case highlights that point‐of‐care ultrasound findings can play a potentially dangerous role in confirmation bias and that we should maintain an open mind when making a diagnosis by treating the patient, rather than the ultrasound picture.