Comparison of the effects of two weaning methods of spontaneous breathing trial and synchronized intermittent-mandatory ventilation on the physiological indices of patients with mechanical ventilation

Background: Weaning from mechanical ventilator might be risky since it directly affects the physiological indices of patients. Without success, this process may lead to the need for reintubation. This study aimed to compare the effects of two weaning protocols of spontaneous breathing trial (SBT) and synchronized intermittent-mandatory ventilation (SIMV) on the physiological indices of patients receiving mechanical ventilation in the intensive care unit (ICU).

Methods: This clinical trial was conducted on 44 intubated patients admitted in the ICU of a hospital in Arak, Iran in 2014. Patients were selected via convenience sampling and randomly allocated to two groups of intervention and control (n=22). SBT and SIMV were used as the weaning protocol in the intervention and control groups, respectively. Data were collected through the measurement of physiological indices and calculating Glasgow coma scale (GCS) scores before, during, and after the intervention. Data analysis was performed in SPSS version 20 using paired T-test, independent T-test, repeated measures ANOVA and Greenhouse-Geisser correction.

Results: In the SBT group, mean systolic blood pressure (107.90±5.2), heart rate (70.27±7.2), and respiratory rate (14.90±1.06) had a significant reduction after the intervention (9-12 am) (P<0.001). Moreover, mean Pao2 (89.12±1.16), diastolic blood pressure (76.09±4.6), SaO2 (93.09±0.97), and consciousness level (14.90±0.21) significantly increased after the intervention, improving the physiological status of the patients. However, no significant differences were observed in the physiological indices of the control group.

Conclusion: According to the results of this study, SBT improved the systolic and diastolic blood pressure, heart rate, Pao2, SaO2, and consciousness level of the patients in the intervention group. Therefore, it is recommended that this method be applied for weaning from mechanical ventilator in ICUs.