For the purpose of assessing the spread of the local anaesthetic after injecting it between abdominal muscles on both sides, the investigators will test if the patient can feel a change in the perception of cold and warm, as well as being pricked with a blunt needle. The investigators will also take several blood samples, together with routine samples, to measure the concentration of the local anesthetic in the blood.

Inclusion Criteria:

• undergo abdominal surgery, eligible for TAP block, over 18, BMI 20-40

Exclusion Criteria:

• does not speak danish, does not consent, does not fulfill inclusion criteria

Patients undergoing abdominal surgery