Noninvasive ventilation as a ventilating and weaning technique in acute-on-chronic air flow limitation

SummaryAcute exacerbation of Chronic Obstructive Pulmonary Disease (COPD) is a frequent cause of admission to the hospital and to the Intensive Care Unit (ICU) and is one of leading causes to death allover the world. Several studies were done in a trial to improve the methods of treatment and increase the choices for treatment without affecting morbidity and mortality of patients.NIV offers a number of potential advantages over invasive positive pressure ventilation. The most important advantages are avoidance of intubation-related trauma, decreased incidence of nosocomial pneumonia which is a frequent complication of mechanical ventilation and is important factor in determining the outcome of respiratory failure. Moreover, endotracheal tube deprives the patient of the ability to communicate easily. Also, NIV shortens the duration of ventilator use, a reduction in hospital stay, and ultimately reduced cost.This study was done in two parts.First part of the study aims to evaluate NIV as a method of ventilation with assessment of predictors of success and failure. This part includes 20 patients after selection criteria.Second part of the study aims to evaluate NIV as a method of weaning from endotracheal mechanical ventilation in comparison with invasive pressure support ventilation. This part included 20 patients use NIV and 15 patients on invasive pressure support ventilation.Results of the study:NIV can be used successfully for management of acute exacerbation of COPD.Also, this first part of the study showed that predictors of success including rapid improvement of conscious level and patients with good conscious level on admission showed rapid improvement.- Early reduction in PaCO2 and rise in pH are predictors of success.- Early reduction in respiratory rate, heart rate and improved exhaled tidal volume are predictors of success of NIV.The second part of the study showed reduction of total duration of endotracheal intubation and decreased subsequent complications related to endotracheal tube. Mortality and morbidity reduced with NIV in comparison with invasive pressure support ventilation. Both NIV and IPSV as a method of weaning from prolonged ETMV are equal in results and improving gas exchange. NIV neither shortened the length of ICU stay nor the hospital stay in comparison with invasive pressure support ventilation.NIV not a substitution of intubation but a modality of treatment and more success can occur if selection criteria and guidelines for NIV is followed.Conclusion• NIV can be used successfully as a ventilatory mode in selected patients with COPD exacerbation.• NIV avoids intubation, reduces the morbidity and possibly the mortality associated with COPD exacerbation.It is possible to use NIV immediately as an early extubation and weaning technique in intubated ACRF patients who are difficult to wean. In this situation, NIV permits earlier removal of the endotracheal tube and reduces the duration of daily ventilatory support during the weaning period without increasing the risk of weaning failure over that with conventional weaning using IPSV.• Level of consciousness, HR, PaCO2 and pH are good predictors of success of NIV.Recommendations- There is some factors which can lead to failure of NIV that can be avoided and corrected. The most important is lack of trained nurses and attendant physicians and this can be corrected by arrangement of training courses in COPD, modalities of treatment selection criteria for NIV or intubation from the start and monitoring of patient with NIV. Also, the physicians must be trained how to help patients to synchronize with NIV.- Further studies on NIV on a wide scale in all units and its role in home therapy.