The study aims to investigate the effect of using a multifunctional baby carrier with rocking, safe swaddling, and white noise features on physiological parameters, crying, and sleep status in infants aged 0-3 months who have undergone congenital heart surgery. It is planned to be conducted in a randomized controlled crossover design. Following congenital heart surgery, the use of sedative interventions in the high-stress environment of the intensive care unit has a significant effect on preserving the energy reserves necessary for the infant's growth and development. Using a sensitive and soothing mobile crib to assist in the postoperative care of infants who have undergone congenital heart surgery is a potential opportunity for the infant, nurse, and parent. The combined application of swaddling, sound, and movement reduces the baby's fussiness and has a calming effect on their physiological activation.

Infants who underwent heart surgery between 0-3 months and were followed up in a multi-purpose baby carrier (swaddling, white noise, and rocking) compared to infants in the follow-up experimental group, compared to infants in the control group who were only swaddled;

Hypothesis 1: The heart rate is lower. Hypothesis 2: Blood pressure is lower. Hypothesis 3: Oxygen saturation levels are higher. Hypothesis 4: Sleep durations are longer. Hypothesis 5: Pain scores are lower.

This thesis study was designed to investigate the effect of using a multifunctional baby carrier with rocking, safe swaddling, and white noise features on physiological parameters, pain, crying, and sleep status in infants aged 0-3 months who underwent congenital heart surgery.

The sample size for the study, which is a 2x2 crossover design, was calculated using power analysis a large effect size and 80% power, resulting in a sample size of 52. Infants will be assigned to groups using simple randomization.

The dependent variables of the study are the infant's heart rate, blood pressure, oxygen saturation, sleep status, pain scale score, and crying duration. The independent variables are: the baby's gender, the baby's age, the postoperative day, the time spent at home with the parent, swaddling, white noise, and rocking.

Research groups: 1. Swaddling group (control), 2. Swaddling combined with rocking and white noise feature in a multifunctional primary cradle group.

In the crossover design, two groups were defined: Group A and Group B, where interventions were applied in different orders.

The data collection tools used in the study were the Infant Information Form, Infant Intervention Monitoring Form, Neonatal Pain, Agitation, and Sedation Scale (N PASS), Pediatric Sequential Organ Failure Assessment Score (pSOFA), Informed Consent Form-Parent Form, monitor , actigraph, stopwatch, decibel meter, swaddling cloth, and multi-functional baby carrier crib will be used as data collection tools in the study. Research data will be analyzed using the Statistical Package for Social Sciences (SPSS) program.

The safety of patients' vital sign data will be ensured through graphs. Pain assessment using the N-PASS scale will be evaluated by the same two observers, and inter-observer agreement will be examined.

Inclusion Criteria:

• Babies born at 38 weeks or later
• Babies aged 0 to 3 months after birth
• No illness other than congenital heart disease
• Who has undergone surgery for the first time due to congenital heart disease
• Whose clinical condition is stable (PSOFA score below 8 points)
• Infants with stable thermoregulation

Exclusion Criteria:

• Babies born before 38 weeks of pregnancy
• Babies older than 3 months
• The presence of other chromosomal or neurological disorders and syndromes in the infant
• Those who have undergone two or more surgeries due to congenital heart disease
• pSOFA score above 8 points

The consent forms stated that the confidentiality of the information would be protected and that it would be used only for the evaluation of the data in this study without identifying information.