Vasopressors may be needed after head and neck microvascular reconstructions to maintain sufficient mean arterial pressure. This is crucial for the flap survival. The study hypothesis is that norepinephrine and dopamine used as vasopressors do not affect flap tissue oxygen level and microdialysate metabolites.

Inclusion Criteria:

• head and neck cancer patients having tumor ablation surgery and reconstruction with microvascular radial forearm flap

Exclusion Criteria:

• Patients having contraindications for the operation.
• Patient refusal to participate in the study