This study assess the relation between intra abdominal pressure and collapsibility index of inferior vena cava in emergency bedside ultrasonography before and after fluid therapy.

Inclusion Criteria:

• Body Mass index less than 30
• Written agree of the patient to participate in the study

Exclusion Criteria:

• neurogenic bladder or any documented previous surgery on bladder, spastic or contractile bladder
• large abdominal hernia
• patients who received neuromuscular blocking agents
• Patients with abdominal respiration due to chest pain