Prognostic Value of Lung Ultrasound in Predicting Intensive Care Unit Length of Stay in Adult Cardiac Surgery: A Prospective Observational Study

After approval of the local institutional ethics committee and local institutional review board. All patients scheduled for open heart surgery in Fayoum university hospital starting from August 2020 will be enrolled in this prospective observational study until fulfilling sample size. A detailed informed consent will be signed by the eligible participants before recruitment ANESTHETIC TECHNIQUE All patients will be preoperatively assessed and investigated by complete blood count, coagulation profile, Liver and kidney functions and serum electrolytes. Chest X-ray, Electrocardiography (ECG) and echocardiography will be routinely done. Coronary angiography and carotid arterial duplex will be requested if needed.

Patient will be premedicated by 10 mg morphine intramuscularly at morning of the operation. Prior to induction of anesthesia, standard monitoring will be applied including a five-lead electrocardiography system, a pulse oximeter probe. A peripheral intravenous (IV) cannula will be placed. An arterial will be inserted using a 20 G cannula either right or left radial artery under local anesthesia. After pre-oxygenation, general anesthesia will be induced using midazolam 2-5 mg, fentanyl (3-10 μg/kg), propofol (1-1.5 mg/Kg), followed by atracurium (0.5 mg/kg).

After trachea intubation, patients will be mechanically ventilated with oxygen in air so as to achieve normocarbia. A main stream capnogram, an esophageal temperature probe and a Foley catheter will also be placed. A triple-lumen central venous catheter will be placed usually through the right internal jugular vein.

Maintenance of anesthesia will be achieved by inhaled Isoflurane 0.4 to 1% and atracurium infusion at a rate of 0.5 mg/kg/h. After initiating extracorporeal circulation, Propofol infusion at a rate of 50-100 µg/kg/min will be added to replace isoflurane inhalation.

Patients will receive intravenous heparin (300-500 IU/kg body weight) before the initiation of cardiopulmonary bypass (CPB) to achieve an activated clotting time (ACT) of more than 480 seconds. Cardiopulmonary bypass was instituted with the use of a non-pulsatile blood flow at 2.4 L/min/m2, a non-heparin-coated circuit, and a membrane oxygenator. Mean arterial pressure will be adjusted to exceed 60mmHg before, during and after cardiopulmonary bypass (CBP) . Cardiac arrest will be induced using St Thomas crystalloid solution (Hamburg). Lactated Ringer's solution will be added to the CPB circuit to maintain reservoir volume if needed, and packed red blood cells will be infused when hemoglobin level drops to less than 7g/dl. After rewarming the patient to 37°C and weaning from CPB; Protamine sulfate will be used to reverse the effect of heparin.