The effect of clonidine on heart rate variability analysis in patients undergoing key-hole surgery to remove gallbladder

This study is looking at how a medication called clonidine affects a new type of anaesthetic monitor called the Analgesia Nociception Index (ANI). The ANI monitor uses changes in heart rate patterns to estimate how much pain a patient is feeling during surgery. Clonidine is a non-opioid pain reliever and sedative. Researchers want to know if clonidine changes the ANI readings in a way that could affect how anaesthesiologists use this monitor during keyhole gallbladder removal surgery. You may be eligible if: - You are 18 years or older - You are scheduled for laparoscopic cholecystectomy (keyhole surgery to remove the gallbladder) You may NOT be eligible if: - You are unable to give consent - You are under 18 years old - You have a pre-existing heart rhythm problem (arrhythmia) - You have an allergy or sensitivity to clonidine - You have diabetes with nerve damage (autonomic neuropathy) - You have sepsis or unstable blood pressure - You have chronic pain Talk to your doctor about whether this trial might be right for you.