A prospective, randomized comparative study where investigators present results of off pump bidirectional Glenn operation done using either a venoatrial shunt or external shunt to decompress superior vena cava during clamping.

The bidirectional Glenn shunt (BDG) is performed for cyanotic congenital heart defects, with single-ventricle pathology . The BDG is usually performed with cardiopulmonary bypass (CPB) with its associated complications. The conduct of this operation without CPB can be associated with elevation of superior vena caval (SVC) pressure that may lead to neurological damage.

However, the safety of performing BDG without CPB reported by many authors but with some decompression techniques of the SVC at the time of clamping

Objective: investigators present results of off pump bidirectional Glenn operation done using either a venoatrial shunt or external shunt to decompress superior vena cava during clamping.

Design A prospective, randomized comparative study Setting: Single tertiary care cardiac center Participants 30 patients with functional single ventricle who will go off pump bidirectional Glenn.

Interventions: The patients will be randomly assigned into two groups: Group I (n = 15), where it will be done with a veno-atrial shunt(internal), and Group II (n = 15), where it will be done with an external shunt. All patients will go a complete neurological examination both preoperatively as well as postoperatively Intraoperative data will be collected and analyzed at the following time points: pre-clamping (post induction), during clamping and after de-clamping of SVC. variables such as arterial oxygen saturation (SaO2), systolic blood pressure (SBP), mean arterial blood pressure (MAP), diastolic blood pressure (DBP), and hematocrit, CVP, SVC pressure, cerebral perfusion pressure (CPP= MAP-CVP), PaO2, PaCO2 and ScvO2 will be analyzed.

Postoperatively, the patients will be stabilized in the intensive care unit (ICU) and after monitoring the SVC pressure for 12 h, the internal jugular vein cannula will be removed to prevent any jugular vein thrombosis. The patients will start aspirin (5 mg/kg/day), which will be continued indefinitely.

Inclusion Criteria:

• single-ventricle lesions,
• good sized branch pulmonary arteries (Magoon's index > 1.5),
• PA pressures < 20 mmHg,
• So2 < 80%,
• age range from (6 months-5years)
• weight range from (6-21) kg, -All these patients had adequate atrial septal defects and none of these patients required any intra cardiac repair.-

Exclusion Criteria:

• previous cardiac operation,
• known intracranial pathology,
• neurologic disease
• craniofacial anomalies.

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