Background: Current evaluation methods for nurse anesthesia students primarily assess didactic knowledge while lacking measures to evaluate students' critical thinking and application of clinical knowledge in decision making (Council on Accreditation of Nurse Anesthetists [COA], 2022; Staun et al., 2020). Purpose: This study aimed to develop an assessment tool to capture critical thinking through clinical actions in nurse anesthesia simulations. The tool sought to support educators in assessing students' application of didactic knowledge during a real-time scenario by identifying critical decision points. The study used a high-fidelity simulation to examine how critical thinking integrates with clinical decision making to contribute to a nuanced evaluation resource for nurse anesthesia education. Theoretical Framework/Philosophical Underpinnings: The study's theoretical framework combines constructivist principles with the Paul-Elder critical thinking model and Bloom's Taxonomy that support higher-order cognitive processing. Methods: This study employed a 3-phase, qualitative content analysis approach. Phase 1 involved a non-medical participant reviewing a simulated rapid sequence induction (RSI) video to help capture clinical steps objectively and avoid assumptions tied to tacit knowledge. Phase 2 engaged an expert panel to evaluate the tool's content validity through the Content Validity Index and semi-structured interviews for refinement. In Phase 3, faculty used the tool in simulation debriefings to assess its practical reliability in capturing critical thinking. Results: The results indicated the tool's effectiveness in evaluating critical thinking and decision making under simulated conditions, particularly in RSI scenarios. Thematic analysis emphasized the tool's ability to bridge the gap between didactic knowledge and practical decision making. Statistical analysis showed moderate to perfect interrater reliability (Cohen's kappa = 0.5 to 1.0) and high content validity. Conclusions: Conclusions suggest that while promising, the tool requires further refinement to ensure consistent use across different raters. Recommendations include improving its capacity to capture clinical rationale, increasing the sample size to mitigate variability, and adding customizable sections to reflect diverse anesthesia practices. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]