Young female with abdominal pain and intra-abdominal free fluid: The risk of confirmation bias associated with point-of-care ultrasound

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.