الفهرس 
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Abstract
Summary & conclusion
summary
The present study was conducted to:
Assess the value of combining T-piece trial to PSV trial in predicting successful weaning in mechanically ventilated patients with chronic obstructive pulmonary disease.
We recruited in this study eighty patients classified to:
(1) 40 patients were weaned by PSV alone.
(2) 40 patients were weaned by PSV + T-piece.
The diagnosis of the case is confirmed on the basis of medical history, physical examination and chest radiography.
We excluded from our study patients under age of 18 years, previous tracheostomy, central nervous system disorders unrelated to hypercapnic encephalopathy or hypoxemia, neurological and neuromuscular diseases, patients who experienced unplanned extubation before or during the weaning process and patients with post arrest encephalopathy.
Patients who were receiving mechanical ventilation >24 h were assessed daily for readiness to wean. Weaning begins by subjective assessment and objective measurement of the following respiratory, mechanical and biochemical parameters.
Usually SBT was conducted early in the morning, when the patient was fully rested and there was a full complement of staff available. It initiated while the patient is awake, co-operative and not receiving sedative infusions. Before the start of SBT, Communication with patient and explanation of the procedure was done. A calm peaceful environment and encouragement was considered in all patients. The baseline parameters were recorded. The duration of the trials ranges between 30–120 min.
During SBT the patient should be subjectively observed for dyspnea, fatigue, anxiety and distress. The criteria for passing a SBT include good respiratory pattern, adequate gas exchange, hemodynamic stability and patient comfort. Arterial blood gases were done at the end of SBT. Patients in whom the spontaneous breathing trial was successful were then extubated and receive supplemental oxygen via a face mask, while if the patient was unable to tolerate the SBT, he wasn’t extubated and return back to full support of mechanical ventilation and it’s called failed spontaneous breathing trial, another trial was done after 24 hours.
In our study, the mean age of patients in both groups was 62.85 years old. As regards baseline data and at the start of weaning trial no significant difference between both groups was found. However, the determined statistical significance was of minimal clinical importance, since all other parameters had no significant difference between both groups. So, we can propose that both modes of weaning (PSV vs. T-piece) can be conveniently compared with each other in term of weaning course and outcome and also as the regard fate of extubation, length of stay, occurrence of complications and mortality.
When comparing gasometric parameters before and after the use of T-piece in group II patients, we found that there was a significant decrease in pH, PaO2, and SaO2 with a significant increase in PaCo2. And that may be due to ETT-imposed respiratory work load.
The majority of total patients (62.5%) had simple weaning, while (22.5%) had difficult weaning and only (15%) had prolonged weaning.
Regarding weaning duration, it was shorter in group I than group II (18.7± 32.1 vs. 19.85± 31.85) hours. Moreover, hospital mortality was less in group I than group II (12.5% vs. 17.5%).
Pressure support ventilation method was more successful than PSV + T-piece method in the weaning of mechanically ventilated COPD patients. PSV is commonly used to counteract the work of breathing imposed by endotracheal tubes and ventilator circuits. Theoretically, this should help with weaning, because a patient who is comfortable at the compensatory level of pressure support should be able to sustain ventilation after extubation.
Conclusions
The overall conclusions from our study are:
1- In a respiratory ICU population, PSV was safe, reliable and can be reasonably used for weaning trials. PSV confers a potential benefit in weaning duration, weaning category, numbers of spontaneous breathing trial, ICU length of stay, complications and mortality rate.
2- The addition of T-piece after PSV provides no benefits in weaning of COPD patients, but it can cause more complications, longer duration of hospital and ICU stay and longer duration of weaning.
3- An efficient weaning process reduces time on the ventilator and improves patient outcomes.
4- Smoking was the most important risk factor for COPD.
5- Most of COPD patients were between the age of 55 to 70 years old.
6- The commonest comorbidity in COPD patients were obesity, diabetes mellitus and systemic hypertension.
7- The most common complication of long duration mechanical ventilation is ventilator associated pneumonia and electrolyte disturbance.
Recommendations
1- Study the impact of additional T-piece in the weaning of mechanically ventilated patients with chest diseases other than COPD.
2- Compare between PSV and other methods of weaning of mechanically ventilated patients with COPD.