The Applied Advantage Of Sequential Noninvasive Following Invasive Mechanical Ventilation In Acute Respiratory Failure

Objective: Noninvasive positive-pressure ventilation(NPPV) refers to the delivery of mechanical ventilation to the lungs using techiques that not require an endotracheal airway. It can maily reduce the time of intubation tube and the incidence rate of ventilator-associated pneumonia(VAP) etc. So it is welcome to medical workers. Recently some research work applied NPPV in weaning and proposed strategy of "sequential noninvasive following invasive mechanical ventilation", that is patients with endotracheal airway was extubated to NPPV before they met standard extubation criteria . Resesrch work found it benefit to chronic obstructive pulmonary disease(COPD). But there are few study use the strategy in acute respiratory failure(ARF) caused by other etiological factor(excluding COPD) and absent randomized controlled clinical trial. Our study is a prospective randomized controlled trial to estimate the feasibility and clinical efficacy of sequential noninvasive following invasive mechanical ventilation in acute respiratory failure caused by multiple etiologcal factors (excluding COPD). Methods: From March 2003 to February 2005, patients who need invasive mechanical ventilation because of multiple cause acute respiratory failure(excluding COPD) were hospitalized in center intensive care unit(Center ICU). we put forward a criteria which indicate patients could extubate to NPPV. when patients met this criteria they prospective-randomized enter NPPV group or conventional group. Patients in NPPV group use NPPV via facial mask with bi-lever positive airway pressure(BiPAP) mode immediately. Patients in control group go on with invasive mechanical ventilation and weaning by synchronous intermittent mandatory ventilation +pressure support ventilation(SIMV+PSV) mode. The data of age,sex,acute physiology and chronic health evaluation Ⅱ(APACHE Ⅱ)sore,arterial blood gas analysis,heart rate(HR),mean arterial blood pressure(MAP),the time when patients met the criteria that we put forward,the length of ICU stay and hospital stay,the incidence of ventilator-associated pneumonia(VAP) and the mortality in hospital were recorded. Results: There are thirty-nine patients involved in the study, among them 20 cases were in NPPV group, the other 19 cases were in control group. The two group had similar age,sex,APACHEⅡ score,HR,MAP,PaO2,PaCO2 and PaO2/FiO2 etc at the time of study beginning and meeting the criteria. the time when patience in two groups met the criteria was 4.5±2.8 days and 4.9±3.7 day(sP>0.05). In NPPV group, after they use NPPV for two hours , patients`s HR,MAP,RR,PaO2,PaCO2 and pH had similar to those were recorded before they use NPPV. For NPPV group and conventional group, the duration of invasive MV was 5.0±3.2 and 14.2±6.7 days(P<0.01),the duration or total MV was 9.4±5.5 and 14.2±6.7 days(P<0.05) , the length of ICU stay was 10.6±5.6 and 15.4±7.0 days(P<0.05), the expenses for ICU was 31.77±24.02 and 60.70±41.86 thousand yuan (P<0.05). The incedence of VAP was 15% and 47%(P<0.05), the success rate was 80% and 79%(P>0.05), the hospital mortality was 15% and 21%(P>0.05). Otherwise there are two patients with serious complication of airway in conventional group while non in NPPV group. Conclusion: To patients with multiple cause acute respiratory failure(excluding COPD) NPPV applied in weaning can mostly reduce the duration of invasive mechanical ventilation , the duration of total mechanical ventilation,the incedence of VAP,length of ICU stay and expenses for ICU. our study demostrates that the strategy is the feasibility and efficacy in clinical practice.