الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Mechanical ventilation is a daily event in any ICU, using NIV as a weaning facilitating strategy for mechanically ventilated patients after passing Spontaneous Breathing Trial (SBT) recently considered to reduce complications associated with invasive ventilation. Also NIV used early to avoid invasive ventilation especially with COPD patients.
In our performed study we applied NIV for mechanically ventilated patients ≥ 72 hrs. immediately after planned extubation compared to conventional face mask regarding ICU stay, hospital mortality, reintubation rate.
Fifty patients were randomized to two groups 25 patients each, NIV group assigned to apply NIV while FM group assigned to face mask.
The weaning protocol was based on a gradual reduction of pressure-support ventilation mode (PSV) combined with synchronized intermittent mandatory ventilation (SIMV). The adjustments of the mechanical ventilator were as follows: PSV to obtain an expiratory tidal volume of 8 ml/kg; SIMV with a respiratory rate of 10 and a tidal volume of 8 ml/kg, FIO2 ≤ 40%, PEEP required to obtain SaO2≥ 90%, and pressure sensitivity of 0.5 cm H2O. The pressure-support level was decreased by 2 cm H2O every 2 hours until a PSV of 10 cm H2O was reached. If f/TV >105, PSV was increased to the previous value for a minimum period of 6 hours, after which the protocol was then resumed. In the cases in which PEEP exceeded 5 cm H2O, it was gradually decreased by 2 cm H2O every 6 hours until a value of 5 cm H2O was reached. The patient was considered ready for extubation, which was carried out in PSV of 10 cm H2O, PEEP 5 cm H2O, SaO2 ≥ 90%, FIO2< 40%, and f/TV < 105.
NIV was administered with a BiPAP in spontaneous mode for a period of 24 hours. After this period, it was replaced by a nebulization face mask with a flow of 5 L/min. For all patients, the initial expiratory positive airway pressure (EPAP) and delta inspiratory positive airway pressure (IPAP) values were 4 cm H2O and 8 cm H2O, respectively. Values were adjusted whenever required. In cases of hypoxemia, with PaO2 ≤ 60 mm Hg and/or SaO2 ≤ 90%, EPAP was increased by 2 cm H2O until hypoxemia improved, as well as the IPAP level (aim for maximum level ≤ 30 cm H2O), to maintain the delta inspiratory pressure value. IPAP was increased or decreased according to the F/TV ratio, or in cases of hypoventilation with PaCO2 ≥ 50 mm Hg, IPAP was increased until hypoventilation improved with minimal air leakage (15-30 L/min).
Each patient closely observed for vital data, serial ABG’s, respiratory pattern. Our primary outcome was weaning failure and reintubation with resumption of invasive MV, and secondary outcome was to follow up ICU stay and hospital mortality.
Reintubation required within a period of 48 hours after extubation was considered weaning failure in any study group. The decision for reintubation was made by the staff physician at the ICU, in the persistent presence of respiratory distress criteria (either clinical or laboratory): systolic arterial pressure ≥ 180 mm Hg or ≤ 90 mm Hg, heart rate ≥ 140 beats/min, life-threatening arrhythmia, decreased level of consciousness or intense agitation requiring sedation, respiratory rate ≥ 30/min, PaO2 ≤ 60 mm Hg or SaO2 ≤ 90%, PaCO2 ≥ 50 mm Hg, pH < 7.2, or significant difficulty in eliminating respiratory secretions.
At baseline, demographic data (age and gender), Acute Physiology and, duration of mechanical ventilation before extubation, and diseases that led to exacerbation were recorded for all patients. Heart rate, arterial blood pressure, respiratory rate, and hemoglobin saturation were monitored throughout the study for both groups.
Five arterial blood gas analyses were carried out by radial artery puncture at immediate, 2 hours, 6 hours, 12 hours, and 24 hours after extubation for all patients.
Patients were followed up throughout their ICU and hospital stay. The need for reintubation was recorded, as well as the length of ICU stay and hospital mortality.
Our results showed lower rate of reintubation in NIV group (n=2) 8% compared to face mask group (n=8) 32% (p 0.034), higher PaO2 & lower PCO2 in NIV group immediate, 2 hrs, 6 hrs, 12 hrs, and 24 hrs post extubation, and lower PaCO2 in NIV group immediate post extubation. ICU length of stay was significantly different between the groups, with a mean of 8.6 ± 2.1 days in the NIV group and 10.8 ± 3.9 days in the FM group (p 0.024). Hospital mortality rate (within about 30 days) showed a significant difference between groups, with one death (4%) during hospitalization in the NIV group and seven (28%) deaths in the FM group (P < 0.04).
Noninvasive ventilation compared with face mask alone prevented reintubation if done immediately after planned extubation in our targeted patients requiring invasive mechanical ventilation for more than 3 days due to respiratory failure secondary to COPD exacerbation, with significant difference regarding ICU stay and hospital mortality.