PURPOSE: In this study a system dynamics methodology was used to identify correlation and nonlinear feedback structure among factors affecting unplanned extubation (UE) of ICU patients and to construct and verify a simulation model. METHODS: Factors affecting UE were identified through a theoretical background established by reviewing literature and preceding studies and referencing various statistical data. Related variables were decided through verification of content validity by an expert group. A causal loop diagram (CLD) was made based on the variables. Stock & Flow modeling using Vensim PLE Plus Version 6.0b was performed to establish a model for UE. RESULTS: Based on the literature review and expert verification, 18 variables associated with UE were identified and CLD was prepared. From the prepared CLD, a model was developed by converting to the Stock & Flow Diagram. Results of the simulation showed that patient stress, patient in an agitated state, restraint application, patient movability, and individual intensive nursing were variables giving the greatest effect to UE probability. To verify agreement of the UE model with real situations, simulation with 5 cases was performed. Equation check and sensitivity analysis on TIME STEP were executed to validate model integrity. CONCLUSION: Results show that identification of a proper model enables prediction of UE probability. This prediction allows for adjustment of related factors, and provides basic data do develop nursing interventions to decrease UE.
Adult ; Airway Extubation/*psychology ; Female ; Humans ; Intensive Care Units ; Intubation, Intratracheal ; Male ; Middle Aged ; *Models, Theoretical ; Nonlinear Dynamics ; Risk Factors

PURPOSE: This study was done to identify pain perception (P-PER) by nurses and pain expression (P-EXP) by patients in critical care units (ICUs) and degree of agreement between nurses' P-PER and patients' P-EXP. METHODS: Nurses' P-PER was measured with a self-administered questionnaire completed by 99 nurses working in ICUs during May, 2013. Patients' P-EXP was measured with the Critical Care Non-Verbal Pain Scale through observations of 31 ICU patients during nine nursing procedures (NPs) performed between May and July, 2013. RESULTS: Nurses' P-PER was from 4.49 points for nasogastric tube (NGT) insertion to 0.83 for blood pressure (BP) measurement based on a 9-point scale, Patients' P-EXP was 4.48 points for NGT to 0.18 for BP measurement based on a 10-point scale. Eight NPs except oral care showed higher scores for nurses' P-PER than for patients' P-EXP. Position change (p=.019), subcutaneous injection (p<.001), blood sugar test (p<.001), and BP measurement (p<.001) showed significant differences between nurses' P-PER and patients' P-EXP. CONCLUSION: Nasogastric tube (NGT) insertion was scored highest by both nurses and patients. Eight NPs except 'oral care' showed nurses' P-PER was higher or similar to patients' P-EXP, which indicates that nurses may overestimate procedural pain experienced by patients.
Adult ; Aged ; Airway Extubation ; Female ; Humans ; *Intensive Care Units ; Intubation, Gastrointestinal ; Male ; Middle Aged ; Nursing Assessment ; Nursing Staff, Hospital/*psychology ; Pain Measurement ; *Pain Perception ; Questionnaires