Clinical Research Directory

Oxygen Reserve Index in Laparoscopic Colorectal Surgery

During laparoscopic procedures, certain physiological changes occur due to the creation of pneumoperitoneum. One such change is the reduction in portal venous blood flow, which can lead to decreased liver perfusion and acute liver cell injury. Additionally, due to an increased alveolar-arterial oxygen pressure gradient, postoperative atelectasis may occur, leading to hypoxia. In other words, the increased intra-abdominal pressure during laparoscopic surgery-along with the effects of patient positioning and mechanical ventilation used during anesthesia-can worsen low blood oxygen levels, especially in patients with already reduced lung compliance and higher metabolic demands. This makes close monitoring of oxygenation crucial. The Oxygen Reserve Index (ORI) is a relatively new tool that can help monitor both high oxygen levels (hyperoxemia) and drops in oxygen (desaturation) before they become clinically apparent. Studies have shown that ORI values range from 0 to 1, with an ORI of 0 typically corresponding to a PaO₂ level between 80-125 mmHg. A downward trend in ORI can act as an early warning sign of hypoxemia, giving clinicians a chance to act before it's too late. Many studies have highlighted the potential harms of using high oxygen concentrations during surgery. For example, while most hospitals still give patients 100% oxygen before anesthesia (a process called preoxygenation), recent evidence suggests this might increase the risk of atelectasis. Therefore, using 80% or less oxygen is now being recommended in many settings. High oxygen levels have also been linked to increased oxidative stress in the body. In this study, we aim to investigate whether monitoring ORI during extubation can help us detect and prevent both hyperoxemia and hypoxemia-situations that standard pulse oximetry often misses. We plan to compare two groups of patients: one receiving conventional 100% oxygen during extubation, and another receiving 80% oxygen. By monitoring ORI values in both groups, we hope to better understand how different oxygen levels affect patient safety and outcomes.

Effect of Oliceridine Analgesia on Postoperative Nause and Vomiting

Postoperative nausea and vomiting (PONV) is common after surgery and impede rapid recovery after surgery. Patients who undergo laparoscopic colorectal surgery are more likely to develop PONV due to the pneumoperitoneum, interruption of gastrointestinal system, delay of oral feeding, and nasogastric catheterization, as well as postoperative opioid analgesic requirement to control acute pain. Oliceridine is a novel selective μ-opioid agonist. It stimulates G protein signalling but is markedly less potent than morphine for β-arrestin recruitment; the latter contributes to opioid-related adverse events including PONV. It is postulated that G protein-biased agonists may deliver effective analgesia with fewer opioid-related adverse events. This randomized trial aimed to investigate whether oliceridine for patient-controlled analgesia can decrease the incidence of PONV in patients recovering from laparoscopic colorectal surgery.

Posterior Transversus Abdominis Plane Block Combined With Sacral Multifidus Plane Block Versus Posterior Transversus Abdominis Plane Block for Laparoscopic Colorectal Surgery

The aim of this study is to compare perioperative analgesic efficacy and safety profile of combined SMPB and posterior TAP block versus posterior TAP block in patients undergoing laparoscopic colorectal cancer surgery.