Flaps may be monitored for color, warmth, and appearance, and sometimes a Doppler is necessary to monitor vascularity. Necrosis of the tissue is a serious complication of flap procedures and may occur within hours of the procedure. Postoperatively, meticulous management of the blood pressure should occur as hypotension may decrease perfusion to the flap, and hypertension may cause bleeding due to damage to the delicate vessels repaired under the microscope. It is also important to closely observe the appearance of the flap. A pale cool flap may indicate arterial occlusion whereas venous blockage within the flap presents with darker, purple color and edema. The surgeon should be alerted immediately if changes in the flap occur during the postoperative period, which could occur as early as minutes after surgery (Drain & Odom-Forren, 2008; Rothrock & McEwen, 2006; Burns & Blackwell, 2007).