The Perfusion Index of the Ear as a Predictor of Hypotension Following the Induction of Anesthesia in Patients with Hypertension: A Prospective Observational Study

Feasibility study of using perfusion index to predict the timing of laryngeal mask insertion: an observational study

BACKGROUND

Currently, no objective indicators are available to predict the optimal timing for laryngeal mask insertion. Anesthesia depth monitoring devices such as the Bispectral Index (BIS) are not widely applicable for day-surgery patients due to their high cost. Previous literature has reported a correlation between the perfusion index (PI) and the anesthesia depth. Thus, the aim of this study is to verify whether the PI can serve as an indicator for predicting the timing of laryngeal mask insertion.

METHODS

This trial was conducted at a specialized pediatric hospital, with a final enrollment of 164 pediatric patients. After the children entered the room, baseline vital signs and PI1 were recorded. Three minutes after routine anesthesia induction, PI2 was recorded, and then a laryngeal mask was inserted. Then children were divided into the body movement group and the non-body movement group. The diagnostic efficacy of PI and the PI ratio for predicting the timing of laryngeal mask insertion were calculated using ROC curves.

RESULTS

The area under the ROC curve (AUC) for using PI to predict the timing of laryngeal mask insertion was 0.641 (95% confidence interval, 0.542-0.740), P = 0.009, and the cutoff value was 4.37. When PI > 4.37 was used to predict the timing of laryngeal mask insertion, the sensitivity was 53.2%, and the specificity was 73.7%. The AUC for using the PI ratio to predict the timing of laryngeal mask insertion was 0.751 (95% confidence interval, 0.657-0.844), P < 0.001, and the cutoff value was 2.955. When the PI ratio > 2.955 was used to predict the timing of laryngeal mask insertion, the sensitivity was 85.7%, and the specificity was 63.2%.

CONCLUSION

The PI ratio is more suitable than PI alone for predicting the timing of laryngeal mask insertion. When PI increases to three times the baseline PI after induction, laryngeal mask insertion can be considered.

CLINICAL TRIAL REGISTRATION

This trial was registered at the Chinese Clinical Trial Registry ( https://www.chictr.org.cn . Registration number ChiCTR2400083111, Weiwei Cai, 16 April 2024.).

The Use of the Perfusion Index to Predict Post-Induction Hypotension in Patients Undergoing General Anesthesia: A Systematic Review and Meta-Analysis

Post-induction hypotension (PIH) is a common and potentially serious complication of general anesthesia. This meta-analysis (Prospero registration number: CRD42024566321) aimed to evaluate the predictive efficacy of the perfusion index (PI) for PIH in patients undergoing general anesthesia. A comprehensive literature search was performed using multiple electronic databases (Google Scholar, EMBASE, Cochrane Library, and MEDLINE). Studies involving adult patients undergoing general anesthesia, with the PI measured before anesthesia induction and reporting PIH incidence, were included. The primary outcome was the diagnostic accuracy of the PI in predicting the probability of PIH. The secondary outcome was the pooled PIH incidence. Eight studies with 678 patients were included. The pooled incidence of PIH was 44.8% (95% confidence interval [CI]: 29.9%-60.8%). The combined sensitivity and specificity of the PI for predicting PIH were 0.84 (95% CI: 0.65-0.94) and 0.82 (95% CI: 0.70-0.90), respectively. The summary receiver operating characteristic (sROC) analysis revealed an area under curve of 0.89 (95% CI: 0.86-0.92). The Deek's funnel plot asymmetry test indicated no significant publication bias. The PI demonstrates high predictive efficacy for PIH in patients undergoing general anesthesia, indicating that it can be a valuable tool for identifying those at risk of PIH.

Protocol for development and validation of a prediction model for post-induction hypotension in elderly patients undergoing non-cardiac surgery: a prospective cohort study

INTRODUCTION

Post-induction hypotension (PIH) is a common event in elderly surgical patients and is associated with increased postoperative morbidity and mortality. This study aims to develop and validate a PIH prediction model for elderly patients undergoing elective non-cardiac surgery to identify potential PIH in advance and help to take preventive measures.

METHODS AND ANALYSIS

A total of 938 elderly surgical patients (n=657 for development and internal validation, n=281 for temporal validation) will be continuously recruited at The First Affiliated Hospital of Soochow University in Suzhou, China. The main outcome is PIH during the first 15 min after anaesthesia induction or before skin incision (whichever occurs first). We select candidate predictors based on published literature, professional knowledge and clinical expertise. For model development, we will use the least absolute shrinkage and selection operator regression analysis and multivariable logistic regression. For internal validation, we will apply the bootstrapping technique. After model development and internal validation, temporal validation will be conducted in patients recruited in another time period. We will use the discrimination, calibration and max-rescaled Brier score in the temporal validation cohort. Furthermore, the clinical utility of the prediction model will be assessed using the decision curve analysis, and the results will be presented in a nomogram and a web-based risk calculator.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Ethics Committee of the First Affiliated Hospital of Soochow University (Approval No. 2023-012). This PIH risk prediction model will be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ChiCTR2200066201.