Final answer:
The most important assessment for the nurse to complete when evaluating the effectiveness of a postoperative client's intermittent pneumatic compression devices is checking for signs of deep vein thrombosis (DVT) or pulmonary embolism (PE).
Step-by-step explanation:
When evaluating the effectiveness of a postoperative client's intermittent pneumatic compression devices, the most important assessment for the nurse to complete is checking for signs of deep vein thrombosis (DVT) or pulmonary embolism (PE). These are potential complications after surgery that can be prevented or managed by the use of compression devices. The nurse should assess for symptoms such as pain, swelling, warmth, redness, or shortness of breath. If any of these symptoms are present, the nurse should notify the healthcare team immediately.