Intraoperative Bleeding

Functional endoscopic sinus surgery (FESS), or sinusoscopy, is a standard surgical procedure used to treat chronic rhinosinusitis and other conditions of the nasal sinuses. However, bleeding during surgery is a frequent challenge that can obstruct the surgeon's view, lengthen operative time, and increase the risk of complications. Vitamin C (ascorbic acid) supports collagen synthesis, capillary wall strength, and blood vessel integrity, which may help minimize mucosal bleeding during surgical procedures. The purpose of this randomized clinical trial is to evaluate whether administering preoperative Vitamin C reduces intraoperative bleeding, enhances surgical field visibility, and shortens operative duration in adult patients undergoing elective sinusoscopy. Participants will be randomly assigned to one of two groups: * Vitamin C Group: Receives a standardized 500 mg dose of Vitamin C before surgery. * Control Group: Receives standard perioperative care/placebo before surgery. Total blood loss will be recorded during surgery, surgical field clarity will be evaluated every 15 minutes using the Boezaart scale, and participants will be monitored for postoperative bleeding and potential side effects for up to 48 hours.

Cardiopulmonary bypass (CPB) is a process that uses a pump that temporarily takes over the function of the heart and lungs during cardiac surgery to maintain blood circulation and oxygenation. Using CPB during cardiac surgery can result in complications with blood clotting. Blood clotting is achieved when molecules in the blood, called platelets, are able to form together with the help of other clotting factors to form a clot. A drug called desmopressin (DDAVP) is used to help blood clot properly by increasing the amount of clotting factors in the blood. Several studies have shown that desmopressin has the ability to reduce the amount of blood transfusions needed for cardiac surgery patients in the postoperative period. At LHSC desmopressin is frequently requested by Cardiac Surgeons and Anesthesiologists to stop bleeding and promote blood clotting where required. A test called TEG6s platelet mapping is a blood test used to help manage the use of blood products by being able to provide information on platelet function and blood clotting activity. At the moment, there is a lack of information regarding the use of TEG6s platelet mapping to analyze the effect of desmopressin on blood clotting in cardiac surgery patients after CPB. The purpose of this study is to investigate the dose-related effects of desmopressin on platelet function in patients undergoing cardiac surgery with CPB. By using TEG6s platelet mapping, this study aims to observe dynamic changes in platelet function following desmopressin administration at various time points in the perioperative and postoperative periods.

The goal of this clinical trial is to determine if implementing a controlled blood removal protocol (i.e. hypovolemic phlebotomy \[HP\] where approximately 10% of the patient's blood is removed and reinfused following hepatic resection as described in the PRICE-2 clinical trial) will reduce the rate of blood transfusions in liver resection surgery at Kingston Health Sciences Centre. Our goals (not included in the PRICE-2 trial) are as follows: * Improved monitoring of how the body responds during surgery following controlled blood removal. We will conduct blood tests to look at oxygen, carbon dioxide, lactate, and acid (pH) levels in the blood as well as urine output. * Standardized guidelines for how fluids and blood pressure medications are used during surgery to reduce blood loss and keep hemodynamics stable. * Monitor patients' recovery following surgery to track complications, injury to the heart, length of hospital stay, and outcomes for up to 90 days. We will also compare long-term recurrence rate of liver cancer compared to patients in the past at our site who did not receive the controlled blood removal (i.e., HP) prior to surgery.

Nasal surgeries are common day case procedures. Although surgical complications are rare, bleeding decreases surgical field visibility and may cause vascular, orbital or intracranial complications in addition to failure of procedure. So, it is crucial to maintain hypotensive anaesthesia to optimize the surgical field.