Extubation Safety Via Microstream EtCO₂ (IPI) Monitoring

The investigators aim to explore the safety of extubation guided by microstream sidestream End-Tidal Carbon Dioxide (EtCO2) monitoring, specifically using the Integrated Pulmonary Index (IPI). End-tidal carbon dioxide (EtCO2) monitoring is a non-invasive, simple, real-time, and continuous parameter for assessing respiratory function. Using EtCO2 monitoring to observe respiratory changes in anesthetized patients helps clinicians detect ventilation abnormalities early, ensuring patient safety during the perioperative period. This study employs micro-side-stream EtCO2 monitoring based on infrared spectroscopy, which can more accurately and stably identify patients' respiratory changes. This monitor can provide early warnings of airway obstruction and hypoxemia and is suitable for neonatal, pediatric, and adult patients in hospitals, medical institutions, and during intra-hospital transport.

The Integrated Pulmonary Index (IPI) combines four respiratory function parameters-SpO2, PETCO2, respiratory rate (RR), and pulse rate (PR)-into a simplified IPI score ranging from 1 to 10, representing different respiratory states. A score of 1 indicates severe respiratory insufficiency, while 10 represents optimal respiratory function.

Traditional criteria for extubation primarily rely on the clinical experience of anesthesiologists or nurse anesthetists to determine the appropriate timing. However, with the increasing complexity of patient conditions, anesthesiologists face significant challenges in ensuring safe and smooth extubation. Currently, there is no objective monitoring parameter to guide safe extubation. Previous studies on EtCO2-derived IPI monitoring have mostly focused on post-extubation patients in the Post-Anesthesia Care Unit (PACU). Research has shown that a decline in IPI after extubation may indicate suboptimal extubation timing, and timely intervention can effectively reduce the incidence of respiratory adverse events. For example, in patients with sleep apnea, post-extubation IPI monitoring can also reduce the occurrence of hypoxemia. Our preliminary studies have found that using this monitoring method to observe respiratory changes in elderly patients under intravenous anesthesia helps detect hypoxemia earlier. However, there is limited research on the application of IPI monitoring to guide safe extubation.

This study enrolled patients scheduled for elective abdominal surgery under general anesthesia with endotracheal intubation and admitted to the PACU, randomly dividing them into two groups: the conventional extubation group (Group C) and the IPI-monitored extubation group (Group T). Upon PACU admission, all patients were connected to monitoring devices, with the IPI group additionally equipped with an endotracheal tube-connected EtCO2 sampling line for continuous IPI monitoring, while the control group received routine monitoring. In the IPI group, after the return of spontaneous respiration, mechanical ventilation was discontinued, and extubation was performed when the IPI reached ≥8. In the control group, extubation followed the standard PACU protocol. After extubation, respiratory changes were observed in both groups, and adverse events (hypoxemia, duration of hypoxemia, cardiovascular adverse reactions) and interventions were recorded.

By comparing the incidence of hypoxemia, adverse cardiovascular events, intervention rates, and satisfaction surveys from both patients and PACU nurses between the two groups, this study aims to explore the safety of using IPI monitoring to guide extubation in PACU patients recovering from general anesthesia.