This cohort includes adult critically ill patients admitted to the intensive care unit at Hospital H+ Querétaro who required invasive mechanical ventilation for at least 24 hours and received inhaled sedation as their primary sedation strategy during ICU stay. In the study protocol, inhaled sedation is defined as the use of isoflurane administered through an anesthetic-conserving device. Patients in this cohort will be identified retrospectively through electronic medical record review and will be evaluated for total cost of care, duration of mechanical ventilation, ICU length of stay, adverse events, and relevant clinical covariates including age, sex, SOFA score, APACHE II score, and comorbidities. Patients with extracorporeal membrane oxygenation, severe traumatic brain injury, transfer to another unit, or less than 24 hours of mechanical ventilation will be excluded.

This cohort includes adult critically ill patients admitted to the intensive care unit at Hospital H+ Querétaro who required invasive mechanical ventilation for at least 24 hours and received continuous intravenous propofol as their primary sedation strategy during ICU stay. These patients will also be identified retrospectively through review of electronic medical records and will serve as the comparison group for the cost-effectiveness analysis. Outcomes assessed in this cohort will include total cost of care, duration of mechanical ventilation, ICU length of stay, adverse events, and indirect costs, as well as baseline and clinical covariates such as age, sex, SOFA score, APACHE II score, and comorbidities. The same exclusion criteria will be applied to maintain comparability between cohorts.