To study the role of noninvasive ventilation as a weaning mode when compared to conventional weaning

Author: 
Vijayakumar V., Arshad Z., Abbas H and Kushwaha B.B

Background: Noninvasive Ventilation (NIV) delivers mechanical ventilation to the lungs using techniques that do not require an indwelling endotracheal airway. Since it provides partial ventilatory support, NIV is used in preventing reintubation in patients with ARF from COPD, cardiogenic edema. The aim of the study is to evaluate the role of NIV as a weaning mode and to ascertain difference with conventional weaning.
Methods: A randomized prospective study was conducted after getting permission from ethical committee of our university. 40 patients of age group 18-65 years, in ICU who received mechanical ventilation for more than 72 hours were considered and were divided randomly and equally in to 2 groups after satisfying weaning criteria, Group A : Included those patients who were weaned by NIV ( using BiPAP mode with Oro nasal interface ), Group B: Included those patients who were weaned by conventional methods ( Spontaneous mode with pressure support ).
Results: Incidence of weaning failure and reintubation was 35% (7 cases) in Group A as compared to none in Group B (p=0.004). Following this, 7 failed cases from Group A were excluded from assessment, and thus the sample size of Group A was reduced to 13. This was done to compare the hemodynamic profile, duration of hospital stay & ventilator use between the patients weaned by NIV and to that of conventional weaning. Now statistically the difference between two groups for the mean Systolic, Diastolic blood pressures and Pulse rate, was significant at all the follow up intervals (p<0.001) with continuous declining trend of all these variables was observed in Group A patients, along with their mean values lesser than that of group B patients throughout the follow up period. Mean duration of hospital stay and ventilator use was significantly lower in Group A as compared to Group B (p=0.002 & p=0.004 respectively). There was no change in outcome of the patients in terms of VAP between the two groups.
Conclusion: NIV does not prevent the need for reintubation, or reduce the incidence of weaning failure. Despite this NIV can be considered as an alternative weaning procedure taking in to consideration of the advantages provided by them, although a judicious clinical decision of when to wean and selection of appropriate patients gives a favourable outcome in patients who are weaned by NIV.

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