Surgical Pleth Index as a Potentially Useful and Noninvasive Tool for Assessing Tracheal Intubation Conditions in Female Patients During Neuromuscular Blockade-Free Anesthesia.

Background: Neuromuscular blocking agents (NMBAs) are commonly used during tracheal intubation to ensure smoother procedural conditions, but they are associated with the risk of prolonged paralysis and respiratory complications. This study explores the relationship between the surgical pleth index (SPI) measured immediately before intubation and tracheal intubation conditions in patients who did not receive neuromuscular blockers, along with the predictive value of the SPI in these conditions. Methods: A total of 100 surgical patients (excluded 17 patients who did not meet the eligibility criteria) undergoing elective surgery under general anesthesia at The Affiliated Lihuili Hospital of Ningbo University between November 2021 and June 2022 were included, and key parameters, including systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), and SPI, were measured at different time points (T0 to T5). Results: At T2, significant reductions in SBP, DBP, HR, and SPI were observed compared to baseline (T0, after the completion of 6 mL/kg of lactate Ringer's solution infusion) and preintubation values (T1, at the time of loss of consciousness) ( Conclusions: The SPI proves to be a potentially useful and noninvasive tool for evaluating tracheal intubation conditions in female patients without the use of NMBAs.