Effect of Different Proprioceptive Neuromuscular Facilitation Techniques Versus Flow Trigger Sensitivity on Weaning Off Mechanical Ventilation

1\. Pressure support ventilation will be titrated at a level sufficient to achieve a respiratory rate of 20-30 breath/min and tidal volume 4-6 ml/kg. Pressure support will be reduced by 2 cm H2O every hour to reach pressure support 8 cm H2O. Two exercise sessions will be performed, at 9 AM and 5 PM. Training will be based on decreasing the trigger sensitivity gradually in order to increase muscle endurance. The trigger sensitivity will be adjusted to 20% of the first recorded MIP at the start of training (In the first session), inspiratory muscle training (IMT) will be limited to 5 min; afterwards the duration will be increased by 5 min at every session until it reach 30 min. If a patient tolerates 30 min of IMT, The next session will be performed with increasing trigger sensitivity by 10% of the initial MIP. Patients who could not tolerate IMT with 20% of MIP for 5 min were trained with 10% of MIP. Training consists of 5 to 6 sets of repetitions through the trainer.

"1. patients in this group treated with the rhythmic initiation technique derived from the PNF concept. The RIT will be applied in four manual positions of the therapist's hands: The upper and lower chest wall, the sternum and below the rib cage, so that the patient can learn the correct breathing pattern. Verbal commands will be also used by the PT to reinforce the manual stimulation with each pattern/exercise being performed 10 times.~2. patients treated with the initial stretch technique ,This technique facilitates the initiation of inhalation. The IST was applied to help the patient to initiate the inhalation phase, increase the force developed by the inspiratory muscle, and to enhance the active range of motion of the chest wall and the diaphragm. At the final stage of exhalation, when inspiratory muscles will be elongated optimally, the stretch reflex will be initiated by applying a quick tap to elicit a strong and active inspiratory muscle contraction"

"Perioral pressure is provided by applying pressure with the therapist's finger on the top lip between the nose and lip. The pressure is maintained for the length of time that the therapist wishes the patient to breathe in the activated pattern.~Intercostal stretch is provided by applying pressure to the upper border of a rib in order to stretch the intercostal muscle in a downward(not inward) direction. The stretch position is then maintained while the patient continues to breathe in his/her usual manner.~vertebral pressure high - manual pressure applied to thoracic vertebrae in the region T2 - T5.~vertebral pressure low - manual pressure applied to thoracic vertebrae in the region T9 - T10.~Co-contraction of the Abdomen Provided by the therapist by pressing adequate pressure on the lower ribs and pelvis on the same side, so that pressure is applied at right angles to the patient.~Moderate Manual Pressure of the open hand(s) is maintained over the area in which expansion is desired"