Effect of Ultra Filtration on Extravascular Lung Water Assessed by Lung Ultrasound in Pediatric Cardiac Surgery

The anesthesiologist will interview the guardians; examine the patients, checking all routine investigations include: CBC(complete blood count), coagulation profile, liver function tests, renal function tests, blood grouping, chest X-ray, recent echocardiography and angiography if available.

Children will be received Midazolam 0.3 mg/kg IM (intramuscular) and Atropine 0.02 mg/kg IM 10 min as pre-medication before induction.

Induction of anesthesia will be established using fentanyl, 1-5µg/kg, ketamine 1-2 g/kg. Atracurium 0.5mg/kg will be administered to facilitate endotracheal intubation and repeated intraoperative as required to maintain muscle relaxation. Anesthesia will be maintained using sevoflurane 0.3%-2 % in oxygen-air mixture (1:1 ratio). A central venous line will be inserted and arterial line for invasive blood pressure monitoring. The use of inotropes will be guided by the patient's hemodynamics after surgical repair. Dobutamine 5-10 µg/Kg/min, Tridil 1-4 µg/Kg/ min, Adrenaline 0.05µg/kg/min or Milrinone 0.5µg/kg/min will be used according to pathophysiology and Intraoperative state of patient.

In all patients, a median sternotomy will be performed. CPB will be initiated after full heparinization in a dose of 300-400 I.U to achieve a n ACT( activated clotting time) of 450 sec or 3 times baseline reading followed by the standard aorta-bicaval cannulation. A membrane oxygenator (Mini-max Plus; Medtronic Inc., Anaheim, CA) and a non-pulsatile roller pump (model 10.10.00; Stôckert Instruments; Munich, Germany) will be used. Venting of the left heart will be performed with a left atrial vent inserted through a small incision at the interatrial septum. Priming fluids consist of lactated Ringer's solution supplemented with heparin. Fresh whole blood was added to the priming solution in appropriate amounts to achieve a hematocrit of 20% to 22% during CPB ( cardiopulmonary bypass). Moderate hypothermia (26°C to 28°C) will be used during CPB.

After cardiac repair the patient will be weaned from CPB. protamine will be given 3-4 mg/kg to reverse heparin. The control group will not subjected to ultrafiltration and the ultrafiltration group will be subjected to conventional ultrafiltration guided by hematocrit level 28%.