The project is characterized by incorporating multiple clinical, demographic, and
pharmacological variables, along with prediction methods based on machine learning, to
classify the level of sedation of critically ill patients into three broad categories:
underdosage, appropriate dosage, and overdosage. The investigators will compare the
performance of this approach against the current gold standard, which is the use of
validated clinical sedation scales (RASS/SAS).
The design of this project is divided into two phases. The first phase involves a
prospective observational cohort study where demographic, vital signs, ventilatory,
pharmacological, and EEG variables will be collected from ICU patients. The second phase
involves using the data obtained to create a multiparameter model with machine learning
tools that informs ICU staff about the depth of sedation or the degree of hypnosis of
each patient. Data will be collected from two national intensive care units: Hospital
Clinico Red UC-CHRISTUS (associated entity) and Dr. Sótero del Río Hospital (associated
entity). A technical team specialized in data collection and analysis, clinical research,
and algorithm development from Pontificia Universidad Católica de Chile (beneficiary
entity) will use this information to create a retrospective classifier that categorizes
patients into one of three groups: underdosed, appropriately dosed, and overdosed.
Upon admission, comprehensive patient data will be collected, including age, sex, cause
of connection to mechanical ventilation, comorbidities, and educational level. The
researchers will also record the drugs and doses used for sedation, neuromuscular
relaxants, and vasopressor drugs. Sedation will be administered with Fentanyl plus
Propofol or Midazolam, according to usual clinical practices at both participating
centers. Data from the RASS and SAS clinical sedation rating scales will be collected
every hour during two time windows, providing a detailed picture of the patient's
sedation levels.
There will be two data recording windows per patient. Time zero will be when the patient
is intubated and connected to mechanical ventilation. The first collection window will be
between 18 to 30 hours after intubation, for a period of 6 hours during business hours,
aiming to obtain a record of data once the chosen sedation strategy is established and
has presumably stable blood levels of drugs. The second window will start once the
patient's sedation is suspended and will last for at least 6 hours or until the patient
awakens, defined as SAS 4 and RASS 0, with eyes open to verbal command or if the patient
presents agitation and/or delirium according to CAM-ICU. The suspension time will be
recorded, along with the day and time all sedatives are stopped in the continuous
infusion pump.
Demographic (age, previous educational level, SOFA, Charlson, APACHE II), hemodynamic
(systolic and diastolic blood pressure, heart rate, electrocardiography), ventilatory
(oxygen saturation, respiratory rate, ventilatory mode, PEEP, tidal volume, plateau
pressure, peak pressure), electroencephalographic (EEG signal in time domain), pain
(hourly behavioral pain scale), neuromuscular blockade (hourly TOF), and pharmacological
(total mass of sedative drugs used at the time of suspending infusions and plasma samples
of sedative drug concentration at the beginning of both windows) data will be collected.
Once patients wake up, the onset of delirium will be assessed with the CAM-ICU tool twice
a day (AM/PM) by appropriately trained nursing staff.