Pharmacological and non-pharmacological pain management is required to reduce and minimize pain during short-term, mild to moderately painful procedures in children in the intensive care unit. For this reason, non-nutritive sucking, which is one of the non-pharmacological methods used in infants / children, has vital importance in controlling pain, providing comfort and neurobehavioral control, increasing physiological stability and oxygenation, reducing stress, effective functioning of the digestive system, and reducing the risk of aspiration. The Turkish Neonatology Association (2018) also recommends that sick babies be supported with a pacifier or empty breast feeding method while they are being cared for in the intensive care unit. In the literature many painful procedures (circumcision, vaccination, IV catheterization, lumbar puncture) It is reported that when used during the test, it provides an analgesic effect and reduces stress. This method activates the sucking reflex through a non-opioid mechanism when a pacifier is placed in the child's mouth, creating an endogenous analgesic effect as a result of tactile sensitivity and stimulation of mechanical receptors. Since sucking prevents swallowing, it protects the baby/child against aspiration. At the same time, the use of pacifiers in stressed babies/children with tachycardia provides stability in heart rate and increases oxygenation, allowing the baby to calm down. Behavioral organization such as self-consolation and soothing develops, and the time spent for sleep and alertness levels increase. All these situations provide the baby with less energy consumption, thus causing the baby to be discharged earlier. In the treatment plan of stressed babies/children with poor sucking, swallowing and breathing coordination, it is recommended to use a pacifier as it helps neurobehavioral organization and maturation, and supports calming.

The Baby-Friendly Hospital Initiative, launched by the United Nations International Children's Emergency Fund \[UNICEF\] in 1990 to promote and support breastfeeding, established the principles of "Ten Steps to Successful Breastfeeding". It was realized that these principles, which rejected the use of pacifiers in the future, did not take into account the separation of the mother and the baby, and it was suggested that this situation should be brought to the agenda. In 2013, the "Ten Steps to Successful Breastfeeding" application was revised and pacifier use was recommended considering the special situations in which the newborn and mother were separated. In the literature and to prevent delays in nutritional development of babies in intensive care units who have to be separated from their mothers. It is strongly recommended to use pacifiers in justified situations to support the development of maturity levels such as motor organization, neuro behavior. However, it is recommended to stop using pacifiers until the age of 3 at the latest. The habit of sucking, which continues after the age of three, can cause displacement of the teeth, deformities in the teeth, gap between the teeth and narrow-high palate structure.

Painful and invasive procedures for follow-up, diagnostic and therapeutic purposes are an inevitable part of care in the intensive care unit. Effective pain and stress management is at the core of nursing care and is based on a comprehensive assessment of the child's pain and stress. Appropriate assessment of pain response and stress level guides treatment. Physiological changes such as increase in heart rate, respiratory rate and intracranial pressure, increase in blood pressure, decrease in oxygen saturation, sweating in the palms of the hands, change in respiratory pattern, differentiation in skin color and pupil size as a result of activation of the sympathetic nervous system following painful stimuli in children. It is also recommended to use the salivary cortisol level in assessing children's stress and to implement the planned intervention in case of stress. Nurses and the interdisciplinary healthcare team have the responsibility to prevent or minimize pain and stress during these procedures. The nurse's being with the patient for a long time can contribute to the healing process by enabling the evaluation and reduction of the patient's pain and stress. Although many studies have been conducted on the assessment of pain and stress in children dependent on mechanical ventilation, there is no study on the use of pacifiers in children dependent on mechanical ventilation. In this study, a pacifier produced from a modified pacifier shield made of polypropylene (PP), a biocompatible polymer with complete ergonomics, adapted to the intubation tube in children connected to mechanical ventilators, will be used. The fact that the pacifier planned to be used in this study is a pacifier evaluated within the scope of the utility model presents the originality of the study. However, it is thought that the use of pacifiers in children who are dependent on mechanical ventilators, who are in a painful and stressful process, will be beneficial in terms of reducing pain and stress in them and thus providing new evidence to nurses about physiological variables.

Considering the benefits of the pacifier and intubated children between 12-36 months in PICU; Considering the suggestions that they need to calm and soothe themselves, their coordination in sucking and swallowing reflexes is not good, there are risks of aspiration, their weight gain and discharge are prolonged, the physiological stability caused by stress is impaired and pacifiers can be used up to the age of 3 years, the hospital where it is planned to work with them is both intensive and neonatal intensive care unit. Since it was observed that sterile gloves were used as pacifiers in the care unit and PICU infants/children to calm them down, this study was planned to be carried out. Although the use of sterile gloves for this purpose seems to be a good method, it is thought that it is not sustainable in terms of continuing the habit of using pacifiers in the future. The aim of this study was to examine the effects of modified pacifier use on pain, physiological variables and stress level in children aged 12-36 months who are dependent on mechanical ventilation.

The research will be conducted in a City Hospital PICU. During the vascular access procedure; 30 children with modified pacifiers will form the study group, and 30 children with no application will form the control group.

In the study, as data collection tools; Introductory Information Form, Ramsay Sedation Scale (RSS), Face, Legs, Activity, Cry, Consolability (FLACC) Pain Assessment Scale, Physiological Variable Follow-up Form, Salivary Cortisol Level Measurement in Stress Assessment tools will be used.