Intraoperative fluid optimization of patients undergoing total hip or knee arthroplasty using pulse pressure variation obtained by a continuous noninvasive blood pressure monitor

This study is testing a smarter way to manage intravenous fluids during hip or knee replacement surgery under general anaesthetic. Instead of giving a standard amount of fluid to all patients, researchers are using a special non-invasive blood pressure monitor to guide exactly how much fluid each patient needs in real time. The goal is to reduce complications after surgery and shorten hospital stays by keeping patients' circulation as stable as possible throughout the operation. You may be eligible if: - You are 18 years or older - You are scheduled for an elective hip or knee joint replacement surgery - You will have general anesthesia - You have a regular heart rhythm - You have given written informed consent You may NOT be eligible if: - You have an obvious blood flow problem in the arm being monitored - You have a vascular implant in the arm being monitored - You have a known neurological or neuromuscular condition affecting your upper limbs - You have peripheral (limb) oedema (swelling) Talk to your doctor about whether this trial might be right for you.