This study aimed at the impact of the N-acetyl cysteine on the improvement of liver function subsequently on-pum mitral valve replacement. Following a clinical trial design, 54 candidates of on-pump MVR, aged 18 to 70 years, with normal liver and renal function were selected. The candidates were randomly divided into intervention: IV150 mg/ kg N-acetyl cysteine over 15 min, and control groups (normal saline as placebo) (n = 27 in each group).

In a randomized controlled prospective study conducted in a teaching hospital, after approval by the ethics committee and informed consent, 54 candidates for on-pump MVR, aged 18 to 70 years, with normal liver and renal function, were selected. The candidates were randomly divided into intervention: IV 150 mg/ kg N-acetyl cysteine over 15 min then 50 mg/kg over 4 hrs for 3 days, and control groups (normal saline as placebo) (n = 27 in each group).and we will assess the effect of NAC on intra-operative hemodynamics and post-operative its protective rule against oxidative stress and liver dysfunction.

Inclusion Criteria:

• Age from 18 to 70 years
• Both sexes
• Patients undergoing on-pump elective MVR with cold cardioplegia.

Exclusion Criteria:

• Patient refusal.
• Allergy to any of the study medications.
• Emergency procedures.
• systolic dysfunction, left ventricular ejection fraction <40%.
• Pre-existing hepatic dysfunction, which is defined as an increase in liver enzymes AST and ALT >10 times the baseline.
• chronic use of drugs affecting liver functions, e.g., NSAIDs, steroids, and anticonvulsants.

quadrible blinded