Rate of Reintubation in Mechanically Ventilated Neurosurgical and Neurologic Patients: Evaluation of a Systematic Approach to Weaning and Extubation. A Randomized Controlled Trial

Patients who did not meet exclusion criteria were randomized, as soon as all inclusion criteria were satisfied, to intervention or control group. Patient randomized to the intervention group were weaned and extubated following a protocol based on: a) A daily screening of physiological and clinical variables to assess readiness for the Spontaneous Breathing Trial. The criteria for readiness, which had been concurred by all the physicians in staff and agreed by nurses and respiratory therapists, were: 1) Glasgow Coma Scale not lower than 8, 2) presence of clearly audible cough during suctioning 15, 3) tracheal suctioning not exceeding 2/hour, 4) normal Sodium (Na+) blood values, 5) core temperature < 38.5° (C) during the previous 8 hours, 6) inspired oxygen fraction not exceeding (FiO2) 0.4, 7) pH not lower than 7.35, and arterial carbon dioxide tension pressure (PaCO2) not exceeding 50 mm Hg, 8) PaO2/FiO2 above 200 with Positive end-expiratory pressure not exceeding 5 cmH2O, 9) heart rate not exceeding 125 beat / min, 10) systolic blood pressure higher than 90 mmHg without epinephrine or norepinephrine infusion and with dopamine infusion not exceeding 5 mgr/Kg/min. The above described screening was performed every morning until all criteria were all met. b) The patients who passed the screening underwent a one-hour Spontaneous Breathing Trial, breathing through the circuit of a flow triggered ventilator, set to deliver 2-3 cmH2O of continuous positive airway pressure, with FiO2 0.4. The trial was interrupted and mechanical ventilation resumed whenever one of the following occurred: 1) respiratory rate > 35/min, 2) evident respiratory distress (diaphoresis, accessory muscle recruitment, thoraco-abdominal paradox), 3) SpO2 < 90%, 4) systolic arterial pressure < 90 mmHg or > 180 mmHg, 5) heart rate > 140 /min, 6) altered sensorium (obnubilation or agitation). At the end of the trial, patients who had a Respiratory rate/Tidal Volume ratio of 105 or less were considered to succeed the trial and underwent arterial blood gas analysis; patients who had PaO2/FiO2 above 200, pH not lower than 7.35, and PaCO2 not exceeding 50 mmHg were immediately extubated. Conversely, if the Respiratory rate/Tidal Volume ratio exceeded 105 or the arterial blood gas analysis criteria were not met, mechanical ventilation was resumed. The same physiologic and clinical data were available for both groups, however, they were systematically organized and checked (protocol) only for the intervention group. A priori power analysis showed that a recruitment of 300 patients (150 patients per group) over a 21-month period would have allowed detecting a decrease in reintubation from 15% to 5%, with 80% power at the 5% two-sided level of significance. We planned 2 interim analysis after 7 and 14 months, performed by an investigator not involved in the clinical management of patients. The study began on October 1st 2002 and ended on June 30th 2004. Patients already enrolled at June 30th 2004 completed the trial irrespective of the group of randomization.