The purpose of this randomized controlled trial is to determine the effect of different positions (supine, prone, right lateral and left lateral) in post-op term newborns staying in Pediatric Cardio Vascular Surgery (PCVS) Intensive Care Unit on gastric residual volume and comfort level.

In the study, crossover design from experimental designs was preferred. Crossover design is an experimental design type in which two or more interventions are applied in a sequence to each case in the study group. In these studies, each group is its own control group. In this design type, all different interventions in the study are applied to the same case; thus, differences that may arise due to individual differences are prevented. Additionally, less number of cases is sufficient in order to obtain the same number of observation data compared to the other design examples. Due to these properties, randomized crossover design model was used in this study. The study will be conducted in PCVS Intensive Care Unit of a University Hospital in Turkey between October 2020 and August 2021.

In this study, sample size was calculated at the confidence interval of 95% using "G. Power-3.1.9.4" program. In a study the effect size used for determining the sample size in the study was found to be 0.54 based on the mean and standard deviation values of the study. By using this effect size, minimum sample size was found as 38 children in order for the gastric residue amount difference between positions to express statistically significance (p<0.05) with theoretical power of 0.95. By considering that there might be losses in the study, it is planned to include a total of 44 children in the study.

The order of the 4 positions to be given to the infants in the study group (A:Prone Position, B:Right lateral Position, C:Left lateral Position, D:Supine Position) was determined by lot method. 4 different orders were chosen randomly from all possible orders of 4 positions to be given to the infants in the study group (24 different orders). Each different order of the positions was expressed as a group. 4 orders randomly selected from 24 different orders were as follows:

The order in the first group is A, C, D, and B; The order in the second group is D, A, B, and C; The order in the third group is C, B, A, and D; The order in the fourth group is B, D, C, and A.

Groups and position orders according to the result of the draw:

1. st GROUP ORDER; Prone (A), Left lateral (C), Supine (D), and Right lateral (B)
2. nd GROUP ORDER; Supine (D), Prone (A), Right lateral (B), and Left lateral (C)
3. rd GROUP ORDER; Left lateral (C), Right lateral (B), Prone (A), and Supine (D)
4. th GROUP ORDER; Right lateral (B), Supine (D), Left lateral (C), and Prone (A)

Assigning the infants to 4 groups was made in Microsoft Excel program using "RANDBETWEEN" command. All positions will be applied once to each infant. The newborns to be assigned to the groups according to this result are stated in the below table.

Groups Newborns

1. st group A, C, D, B 1, 5, 10, 11, 12, 20, 21, 30, 36, 38, 44
2. nd group D, A, B, C 19, 22, 23, 24, 25, 27, 28, 31, 32, 33, 42
3. rd group C, B, A, D 3, 4, 6, 7, 9, 13, 15, 29, 34, 37, 43
4. th group B, D, C, A 2, 8, 14, 16, 17, 18, 26, 35, 39, 40, 41

Data Collection tools:

In the data collection, "Information Form" prepared by the researcher to record the descriptive information of the newborn, "Newborn Comfort Behavior Scale" to evaluate the comfort level and "Residue Follow-up Form" to record the residual amount and the "Vital Signs Follow-up Form" to record the vital signs will be used.

Information Form: It is a form prepared by the researcher in line with the literature to record the natal and postnatal information of the newborn. The information in this form will be filled out by the researcher.

Newborn Comfort Behavior Scale: It is a Likert-type scale developed to be used to assess sedation and comfort needs, pain, and distress of newborns followed-up in the intensive care. The Newborn Comfort Behavior Scale will be evaluated at the 30th, 60th and 120th minutes after the position. The comfort level scale scoring will be evaluated and filled by the researcher and a second observer working in the Intensive Care Unit for 5 years.

Residue Follow-up Form: The form prepared to follow up the residue includes the position given, amount of nutrition, the way of feeding, feeding type, and residue amount control. The researcher will evaluate and fill out the form at the 30th, 60th and 120th minutes after feeding.

Vital Signs Follow-up Form: This form prepared by the researcher in line with the literature was composed of the parameters of heart rate (min), respiratory rate (min) and oxygen saturation value (%SpO2) of the newborn. The researcher will evaluate and fill out the form at the 30th, 60th and 120th minutes after positioning.

Inclusion Criteria:

• • Having a gestational week of 37 and above,

  • Undergoing heart surgery,
  • Being separated from the mechanical ventilator,
  • Starting to be fed with nasogastric or orogastric tube,
  • Not showing any signs of infection,
  • Not using narcotic drugs in post-op period,
  • Having no factors that can interfere with feeding (vomiting, distention, necrotizing enterocolitis, etc.)
  • Having no condition that can prevent positioning,
  • Receiving Informed Consent Form from their families.

Exclusion Criteria:

• • Having a gestational week of less than 36+6 days,

  • Have not been separated from the mechanical ventilator,
  • Showing any signs of infection,
  • Using narcotic drugs in the post-op period,
  • Having factors that may prevent feeding (vomiting, distention, necrotizing enterocolitis, etc.)
  • Having a condition that can prevent positioning,
  • Receiving no consent from their mother or father.

It will be shared after the article is published.