RT Journal Article
SR Electronic
T1 Classifying Different Types of Double Triggering Based on Airway Pressure and Flow Deflection in Mechanically Ventilated Patients
JF Respiratory Care
FD American Association for Respiratory Care
SP 460
OP 466
DO 10.4187/respcare.00731
VO 56
IS 4
A1 Kuang-Ming Liao
A1 Chih-Ying Ou
A1 Chang-Wen Chen
YR 2011
UL http://rc.rcjournal.com/content/56/4/460.abstract
AB BACKGROUND: Double-triggering (DT) is a frequent type of patient-ventilator asynchrony and has potentially severe consequences, such as alveolar overdistention or the generation of intrinsic PEEP. However, the first breath of DT could be patient-triggered (DT-P), auto-triggered (DT-A), or ventilator-triggered (DT-V). OBJECTIVE: To differentiate DT-P, DT-A, and DT-V using airway pressure or flow changes during the trigger-delay phase in ventilated patients. METHODS: Fourteen mechanically ventilated patients with DT were included. All patients were on flow-triggered ventilation modes and received either continuous mandatory ventilation or pressure support ventilation. Breaths in which the first breath was associated with an esophageal pressure drop of > 1 cm H2O were categorized as DT-P. Breaths in which the first breath occurred at the ventilator set cycle were categorized as DT-V. Breaths in which the first breath occurred earlier than the ventilator set cycle without esophageal pressure drop were categorized as DT-A. The pressure drop and flow change at 0.13 s (PD0.13 and F0.13, respectively) in the trigger-delay phase were calculated from the nadir. RESULTS: There were 507 double-triggered breaths: 271 DT-V (53%), 50 DT-A (10%), and 186 DT-P (37%). The PD0.13 for DT-V, DT-A, and DT-P were 0.16 ± 0.12 cm H2O, 0.25 ± 0.17 cm H2O, and 1.34 ± 0.67 cm H2O, respectively. The F0.13 for DT-V, DT-A, and DT-P were 2.11 ± 2.31 L/min, 2.64 ± 2.07 L/min, and 16.51 ± 8.02 L/min, respectively. The best discriminatory criteria for differentiating DT-P from DT-V and DT-A, based on the Youden index (sensitivity + specificity – 1) was PD0.13 ≥ 0.49 cm H2O, which had a Youden index of 95%. CONCLUSION: DT-P can be distinguished from DT-V and DT-A by using airway pressure deflections in the trigger-delay phase.