الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Difficulties in discontinuing ventilatory support are encountered in 20% to 25%[80] of all mechanically ventilated patients with approximately 40% of total ventilation time spent in weaning [64]
The diaphragm, the principal respiratory muscle in humans, is susceptible to various insults such as hypotension, hypoxia, and sepsis, all of which are common in intensive care unit patients.
Mechanical ventilation in controlled mode and possibly with high levels of partial ventilatory assist can also¬¬¬¬¬¬¬¬¬¬¬¬¬ result in diaphragmatic dysfunction[41]
The aim of our study was to assess whether the degree of diaphragm thickening, measured by ultrasound during a weaning trial and expressed as thickening fraction, may be used to predict successful weaning.
Our study was conducted on 50 mechanically ventilated patients for any cause who are eligible for SBT, diaphragmatic ultrasound was done for all of them. Diaphragmatic paralysis was excluded by US, DTF was then calculated for all patients during SBT.
Our study correlated DTF with BMI, serum electrolytes, clinical comorbidities that may contribute to weaning failure, ICU stay and ventilation days. It was also correlated with weaning from mechanical ventilation, and the risk of reintubation within 48 hours after successful weaning from mechanical ventilation.
Our study found a significant moderate linear relationship between DTF and serum PO4with p values and r 0.035 and 0.5
It showed a significant negative linear relationship between DTF and ICU stay with a p value 0.04 and r = -0.2. While it showed a significant negative linear relationship between DTF and ventilation days with a p value 0.019 and r = -0.1
Our study showed a significant good linear relationship between DTF and VTe with a p value 0.007 and r = 0.75
On the other hand it showed a significant negative linear relationship between DTF and RSBI with a p value< 0.001 and r = -0.3
While it showed a significant moderate linear relationship between DTF and PImax with a p value <0.001 and r = 0.4
Also it showed a significant moderate linear relationship between DTF and weaning from mechanical ventilation with a p 0.014 value and r = 0.3
A ROC curve was calculated for the use of DTF as an index for weaning from mechanical ventilation. The area under curve [AUC] was 0.478 (95% confidence interval0.28 to 0.67) .
The optimal cut-off point of DTF for being an index for weaning from mechanical ventilation was ≥0.28 with a sensitivity of 82.3% and a specificity of 88% and with a PPV value of 0.93 and a NPV 0.88