BACKGROUND: Delayed mechanical ventilation monitoring may impede recognition of lifethreatening acidemia. Coordination of multidisciplinary processes can be improved by using a checklist and time-out procedure. The study objective was to evaluate process-related outcomes after implementation of a post-intubation checklist and time out. METHODS: An observational study of a 24-bed medical ICU in Philadelphia, Pennsylvania, was conducted from January to December 2011. A random sample of mechanically ventilated adults was selected from the preintervention (n ؍ 80) and post-intervention (n ؍ 144) periods. The primary outcome was the proportion of subjects with an arterial blood gas (ABG) result within 60 min of mechanical ventilation initiation. Secondary outcomes included rates of respiratory acidosis, moderate-severe acidemia (pH <7.25), checklist initiation, and project sustainability. Chi-square analysis was used to evaluate differences in outcomes between time periods. RESULTS: After the intervention, the proportion of subjects with an ABG result within 60 min increased (56% vs 37%, P ؍ .01), and time to ABG result improved (58 min vs 79 min, P ؍ .004). Adjusting for illness severity, the proportion with an ABG result within 60 min remained significantly higher in the post-intervention period (odds ratio 2.42, 95% CI 1.25-4.68, P ؍ .009). Checklist adherence was higher with ICU intubations than for intubations performed outside the ICU (71% vs 27% checklist initiation rate, P < .001). Transfer from referring institutions (23% checklist initiation rate, P ؍ .006) negatively impacted checklist use. Implementation challenges included frequent stakeholder turnover, undefined process ownership, and lack of real-time performance feedback. CONCLUSIONS: A post-intubation checklist and time out improved the timeliness of mechanical ventilation monitoring through more rapid assessment of arterial blood gases. Implementing this peri-intubation procedure may reduce the risks associated with transitioning to full mechanical ventilatory support. Optimal implementation necessitates strategies to surmount organizational and behavioral barriers to change.