Purpose: Although the medical decision-making process can be overwhelming for some surrogates, there is a lack of understanding regarding their experiences. The objectives of this study were to examine the decision self-efficacy and decisional conflict experienced by surrogates in intensive care units (ICUs) when faced with the decision of whether to reintubate patients with respiratory failure after a planned extubation. In addition, predictors and mediators influencing these decision-making processes were identified. Methods: This study utilized a cross-sectional design to investigate the decision-making processes of 174 surrogates who were faced with the decision of whether to reintubate patients with respiratory failure after a planned extubation in the internal ICU of a medical center between August 2021 and February 2022. Structured questionnaires were administered to collect data on the surrogates' background information, decision self-efficacy, decisional conflict, and positive and negative affect. The patients’ background information was also collected. Univariate and multivariate analyses were performed to model the data. Results: The mean decision self-efficacy score of the surrogates was 82.41 points, and 20.7% surrogates had decisional conflict scores exceeding 37.5 points, suggesting that they faced challenges in the decision-making process. Surrogates' employment status and negative affect significantly predicted their decision self-efficacy. In addition, patients' activities of daily living prior to hospitalization and the decision self-efficacy of the surrogate significantly predicted surrogate decisional conflict. The impact of surrogates’ negative affect on decisional conflict was fully mediated by decision self-efficacy. Conclusions Surrogate decision self-efficacy mediates the relationship between negative affect and decisional conflict. Providing clinical care interventions that focus on enhancing surrogate self-efficacy and reducing negative affect can help alleviate decisional conflict in this population.