RecruitingClinical trialEffect of Rib Mobilization on Weaning Parameters From Mechanical Ventilator in Patients With Pneumoniathis study will be conducted to distinguish between effect of rib mobilization and routine chest physiotherapy on weaning parameters from mechanical ventilator in patients with pneumonia • HYPOTHESES: It will be hypothesized that there may be significant effect of rib mobilization on weaning parameters from mechanical ventilator in patients with pneumonia. RESEARCH QUESTION: Does rib mobilization have an effect on weaning parameters from mechanical ventilator in patients with pneumonia? measuring weaning parameters: on screen of mechanical ventilator : measuring respiratory rate, Tidal volume (TV), FiO2. * Arterial blood gases (ABG) analyzer machine ABG is recorded daily (PH- PaO2 - PaCO2) * Length of ICU stay: calculated by (admission date - discharge date * Weaning success rate