A newborn's recognition and preference for their mother's voice occurs early in life, very likely during fetal development. Maternal voice stimuli undergo a unique form of cerebral processing that lends support for the existence of neurophysiologic mechanisms that reflect a child's preference for his/her mother's voice. This study aims to evaluate and compare the effect t of maternal sound listening in children undergoing cardiac surgery on stress response and physiological parameters.

Children (4 to 8 years) undergoing repair of Atrial Septal Defect (ASD). Patients will be randomized into two equal groups (30 in each group) (control group and maternal sound group); in control group patients listened to a blank CD, while in maternal sound group patients listened to a recorded CD where the mother singing the most popular songs their children like or telling a story to their children. Baseline stress markers (blood glucose and plasma cortisol) sampled the morning before scheduled operation. A interview with the patients and their parents before operation to collect the questionnaire regarding patient's characteristic (age, sex, weight and height), patient's clinical data (medical diagnosis and American Society of Anesthesiologists physical status) and haemodynamic data (blood pressure, heart rate, oxygen saturation on room air, temperature). In addition, the researcher interviewed with the mothers to record on one CD their voice while they are singing the most popular songs their children like or telling a story to their children to help them to sleep to be used during intra-operative period in maternal sound group.

Inclusion Criteria:

• Age range 4-8 years
• Elective cardiac surgery
• Atrial Septal Defect (ASD) repair with Cardiopulmonary bypass

Exclusion Criteria:

• Previous cardiac surgery
• Diabetes mellitus
• Hearing impairment
• Psychiatric illness
• Neurological illness.