Schädler 2012.

Methods	Single centre (multiple ICU) randomized controlled trial
Participants	300 surgical adult patients (Intervention 150; Control 150) who at 09:00 AM, were ventilated for longer than 9 hours since ICU admission. Exclusion criteria comprised: cerebral surgery/trauma, age <18 years, do‐not‐resuscitate order, duration of ventilation > 24 hours, patients already enrolled in the study. Setting: Germany, academic tertiary hospital, 3 ICUs serving all surgical disciplines (10 bed cardiovascular ICU, 10 bed interdisciplinary ICU and 8 bed surgical ICU). ICUs staffed with a 1:2 nurse:patient ratio. During daytime a board certified physician was responsible for medical care + 1 resident for 3 shifts per day and 1 consultant on‐call. Daily ward round carried out by 2‐3 experienced intensivists, one resident, one consultant microbiologist and 1‐2 nurses.
Interventions	In both study arms, haemodynamically stable patients (maximal continuous infusion of epinephrine or norepinephrine of 0.01 mg/kg/h) were assessed with a 30 minute pressure support test initiated by the responsible physician or during study visits if clinically indicated. Patients were switched from PCV to PSV with PS between 15 to 30 cmH2O and identical settings of FiO2 and PEEP. Patients passed the PS test if remained clinically stable, spontaneous breaths were <35 per minute, VT ≥ 6 mL/kg predicted body weight with allowed PS, SpO2 ≥ 90%. Patients successfully passing the PS test were then weaned according to the allocated group. Intervention: SmartCare/PS™ via Evita XL ventilators with night rest and automatic tube compensation turned off and using a heat and moisture exchange filter. Readiness for extubation was identified by SmartCare/PS™. Extubation or end of ventilator therapy for tracheostomized patients occurred when the following criteria were satisfied: PaO2/FiO2 >200, patient awake and cooperative, sufficient airway protection or GCS >8, effective cough, and no surgical indication. Control: Standardized weaning protocol. Adjustment of PS at least 3 times per day by 2 or 3 cmH2O with the aim of maintaining the spontaneous breath rate ≤ 35 and good clinical adaptation. PS was increased if the spontaneous breath rate was >35 for longer than 3 minutes. A daily SBT lasting 30 minutes was commenced when PS ≤ 12 cmH2O, PEEP ≤ 5 cmH2O and FiO2 ≤ 0.5. Patients were deemed to have passed the SBT if the spontaneous breath rate remained below 35, SpO2 ≥ 90%, patient remained clinically stable (no diaphoresis, agitation or decreased level of consciousness). If a patient failed the SBT the test was reinitiated at least once during the next 24 hours. The same criteria were used for extubation/discontinuation of ventilation as used in the intervention arm. Analgesia was maintained by a continuous infusion of sufentanil (range 0.1 to 0.4 μg/kg/h). Sedation was achieved via continuous infusion of propofol (max 4 mg/kg/h) for 24 hours after inclusion. Thereafter bolus doses of midazolam were used to maintain a Ramsay score of 2.
Outcomes	Overall ventilation time during ICU stay considering any time the patient required invasive or noninvasive ventilation during the 28 day study period Time in zone of respiratory comfort Number of ventilator manipulations Length of ICU stay Length of hospital stay 28‐day mortality 90‐day mortality
Notes	Study sponsored by Dräger Medical via a restricted research grant. Sponsor had no role in the study
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Electronically generated and locally maintained randomization schedule
Allocation concealment (selection bias)	Low risk	Allocation was concealed
Incomplete outcome data (attrition bias) All outcomes	Low risk	Attrition reported, analysis according to ITT, no missing outcome data
Selective reporting (reporting bias)	Low risk	All pre‐specified outcomes are reported
Other bias	Low risk	No other sources of bias detected
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not possible to blind personnel
Blinding of outcome assessment (detection bias) All outcomes	High risk	Blinding of outcome assessors not possible. Outcome assessors were also involved in the daily care of patients