Methods
respiratory failure, arrhythmia, SBT failure, notch and gain
RESPIRATORY FAILURE, ARRHYTHMIA
Demographic data (age, sex and ethnicity), profiles of comorbidities and hospital admission parameters (symptoms and time of symptom onset related to difficult weaning, vital signs and laboratory tests) were obtained by authors. A prospective randomized self‐controlled crossover design was adopted in this study. Patients undergoing weaning who were enrolled for SBT observation received the placement of a gastric tube with integrated four‐lumen multi‐functional catheter. The pressure extension tubes of the oesophageal and gastric balloons were connected to the Validyne DP15 pressure sensor (USA). The ventilator circuit was also connected to the Validyne DP15 through pressure extension tubes via a Y‐shaped connector. The three‐channel pressure signals were amplified using a Validyne CD280 pressure amplifier. After adjustments to notch and gain, the pressure were imported into Powerlab and then exported to LabChart 8 for data acquisition.Patients underwent 30 min of either the S group or S1 group in a random order. During SBT, the patient's fraction of inspired oxygen (FiOPatients who successfully completed the SBT were assessed by the attending physician to determine whether they can undergo extubation. Patients who could not tolerate the SBT continued receiving ventilation with adjustments made to the pre‐SBT parameters. The criteria for SBT failure were as follows: RSBI >105, respiratory rate (RR) <8 or >35 breaths/min, spontaneous breathing tidal volume<4 mL/kg, heart rate (HR) > 140 beats/min or changes >20% and occurrence of new‐onset arrhythmia. Patients who developed respiratory failure within 72 h after extubation were reintubated. Weaning success was defined as the absence of reintubation 48 h after extubation (see Figure Flow chart. PEEP, positive end‐expiratory pressure; PS, pressure support; PSV, pressure support ventilation; SBT, spontaneous breathing trials.