Non-invasive mechanical ventilation after the successful weaning: a comparison with the venturi mask

Abstract

Background and Goal of Study: This study compared the rates of acute respiratory failure, reentubation, length of intensive care stay and mortality in the patients in whom the non-invasive mechanical ventilation (NIMV) applied instead of the routine venturi face mask (VM) application after a successful weaning. Materials and Methods: Following the approval of the hospital ethics committee, 62 patients who were under mechanical ventilation for at least 48 hours were scheduled for this study. 12 patients were excluded because of the weaning failure during T-tube trial. The patients who had optimum weaning criteria after the T-tube trial of 30 min. were extubated. The patients were kept on VM for 1 hour to observe the haemodynamic and respiratory stability. The ones who do not fullfill the criteria were mechanically supported (NIMV or IMV) and excluded from the study (n=12). The group of 50 patients who were successful to wean (GCS>13; RR< 25/min; HR>50; < 140/min; SAP>70, < 180mmHg; SaO2>90%) randomly allocated to have either VM ( n=25, 4L/min O2) or NIV ( n=25, oro-nasal or face mask, IPAP: 13-15cmH2O and EPAP:35cmH2O, FiO2: 0.4). Sistolic arterial pressure (SAP), heart rate (HR), respiratory rate (RR), PaO2, PCO2, pH values were recorded before and 30th min. after the T-trial and 1st, 2nd, 3rd, 4th, 5th, 6th, 12th, 24th, 48th hour after the extubation. Patients who develop respiratory failure, who need reentubation were recorded. The lenght of stay and mortality rates were also noted. SPSS 20.0 were used for statistical analysis. Results and Discussion: The demographic data of the groups were similar. The number of the patients who developed respiratory failure in the NIV group were significantly less than VM group of patients ( 3 reentubation vs. 14 NIV+5 reentubation in the VM group; P=0.000). The lenght of stay in the ICU was also significantly shorter in NIV group (5.2 (plus or minus) 4.9 day vs. 16.7 (plus or minus) 7.7 day, p=0.000). The difference in the mortality rates was not statistically significant (8 % in group NIV; 16 % in group VM, p= 0.304). Conclusion(s): The ratio of the respiratory failure and the lenght of stay in the ICU were less when non-invasive mechanical ventilation was used after extubation even if the patient is regarded as 'successfully weaned'. We recommend the use of NIMV in such patients to avoid unexpected ventilatory failure.