A method for handling sudden and substantial pressure changes in invasive arterial blood pressure monitoring, a blood pressure monitoring apparatus, and a computer program product for a blood pressure monitoring apparatus are disclosed. To provide a user of a patient monitor a possibility to readily adapt the alarm functionality of blood pressure measurement to a clinical task without a need to go through a complicated nullifying process of a high priority alarm, a touchable user interface element is produced onto a touch screen of patient monitor if a sudden and substantial change is detected in measured arterial blood pressure of the subject. The user interface element is indicative of an alarm and configured to enable the user to modify alarm functionality of the patient monitor for an intentional clinical task that caused the sudden and substantial change in the measured arterial blood pressure.