Department of Surgery, Ajou University School of Medicine, Suwon, Korea
*Department of Anesthesiology and Pain Medicine, Chonnam National University, Medical School, Gwangju, Korea
Division of Pulmonology, Critical Care and Sleep Medicine, Department of Internal Medicine, St. Paul’s Hospital, The Catholic University of Korea, Seoul, Korea
Department of Pulmonology, Kangreung Asan Medical Center, Kangreung, Korea
Department of Anesthesiology and Pain Medicine, Hanyang University school of Medicine, Seoul, Korea
Department of Anesthesiology and Pain Medicine, Ajou University School of Medicine, Suwon, Korea
University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Korea
Copyright © 2014 The Korean Society of Critical Care Medicine
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Total ventilation time: the time period from the start of MV to the successful weaning end point.
Weaning time: (total ventilation time) – (time of ventilation with the controlled mode), however, if the patient was weaned with pressure control, the duration of the controlled mode was as follows;
Weaning trial: start of weaning according to the following criteria;
Oxygenation: PaO2 > 60 mmHg with FiO2 < 0.4, PaO2/FiO2 > 150, SaO2 > 90%, PEEP < 5 cmH2O, and minute volume < 15 L/min.
Vital signs: mean arterial pressure > 60 mmHg without vasopressor, heart rate < 140/min, 35°C < body temperature < 38°C, and respiratory rate < 35/min.
Clinical status: resolution of acute disease phase, no newly developed definite pulmonary infiltration, Ramsay sedation score 2–4, hemoglobin > 7 g/dl, pH > 7.30, electrolyte within normal range, no active bleeding, no increased intracranial pressure, no bronchospasm, no untreated coronary arterial disease, and no specific treatment such as nitric oxide gas, prone position or operation plan etc.
Successful weaning: more than 48 hours of spontaneous breathing with a T-piece or in the extubated status. Successful weaning marked the cessation of MV.
Primary weaning failure: restart of MV within 48 hours from the weaning end.
Secondary weaning failure: restart of MV between 48 hours and 7 days from the weaning end.
Unsuccessful weaning: no successful weaning within 7 days from the study enrollment.
Data are presented as mean ± standard deviation or %. Primary weaning failure, restart of MV for more than 24 hours within 48 hours after the start of weaning; Secondary weaning failure, restart of MV for more than 24 hours between 48 hours and 7 days after the start of weaning. MV: mechanical ventilation; ICU: intensive care unit.