Background/Objective <p>Outcomes for patients with subarachnoid hemorrhage (SAH) have improved substantially through the years, but there remains room for improvement. The RAISE (pRolonged ventilAtion In Subarachnoid hEmorrhage) score was designed to predict which SAH patients will require prolonged mechanical ventilation. We sought to assess the external validity of the RAISE score in our patient population.</p> Methods <p>This was a single center retrospective cohort study of adult patients admitted to the neurointensive care unit with non-traumatic SAH from July 2017-July 2025. The ability of the RAISE score to differentiate between patients with varying risk profiles was assessed. The predicted probabilities of mechanical ventilation duration &gt; 7&#xa0;days were compared to observed frequencies, and a calibration plot was generated. Multivariable logistic regression was also employed to examine if the components of the RAISE score were significantly associated with prolonged mechanical ventilation in our cohort.</p> Results <p>A total of 202 patients met study criteria. Of these, 49 (24.3%) were mechanically ventilated &gt; 7&#xa0;days. The area under the receiver operating characteristic curve was 0.85, and the calibration slope was 0.60, suggestive of overfitting. Of the 5 RAISE score components, only Hunt-Hess grade (<i>p</i> &lt; 0.001) was significantly associated with prolonged mechanical ventilation in logistic regression.</p> Conclusion <p>While the RAISE score performed well in its original cohort and can discriminate between various risk categories for prolonged mechanical ventilation, results indicate that the score is overfit to the original study population or that there are other confounders present such as differences in practices surrounding intubation, ventilation, and extubation. Future studies could consider utilizing another cohort for assessing external validity or designing a novel scoring system for prediction of prolonged mechanical ventilation.</p>