Abstract Background: Objective Structured Clinical Examinations (OSCEs) are vital for assessing nursing competence. However, the design of OSCE stations, particularly comparing critical (high-stakes) versus routine (low-stakes) scenarios, may differentially impact student stress and clinical performance. This experimental study compared these effects to inform the optimal design of assessments.

Methods: This 2024 experimental study at Torbat Heydariyeh University randomly assigned 78 final-year nursing students to two groups (n=39 each). The Intervention Group faced a critical CPR station where failure resulted in exam disqualification, while the Control Group faced a standard routine station. Both groups received identical Basic Life Support (BLS) training in accordance with the 2020 AHA guidelines. Outcomes were assessed using: (a) the PSS-10 stress scale (α=0.85); (b) a 20-item BLS knowledge test; and (c) a 17-item CPR skills checklist, with performance metrics (depth, rate, ventilation) recorded objectively by a Laerdal QCPR® manikin. Data were analyzed using independent t-tests and the Mann-Whitney test to achieve 80% power.

Inclusion Criteria:

• The inclusion criteria included nursing students in their eighth semester who had given their consent to participate in the study

Exclusion Criteria:

• Exclusion criteria were nursing students who were unwilling to participate, absence in any of the intervention sessions, and those who, for reasons such as acute stress, did not have the necessary mental or psychological readiness to perform cardiopulmonary resuscitation skills. Additionally, students taking medications that could attenuate the stress response (e.g., beta-blockers, central nervous system depressants) were also excluded.