ABSTRACT Objective: To test the effect of the Premature Infant Oral Motor Intervention (PIOMI) at 29-30 weeks post-menstrual age on the development of oral-motor function and sucking capacity.

Study Design: This study was a single-blind randomized controlled experimental design. The sample consisted of 60 preterm babies from two Neonatal Intensive Care Units in Gaziantep, Turkey between May 2019 and March 2020, with 30 each in the control and experimental groups. The PIOMI was applied to the experimental group for five minutes a day for 14 consecutive days. Sucking capacity, growth, feeding outcomes, and length of hospital stay (LOS) were measured. The Yakut Manometer Measuring Suction Power (PCT/TR2019/050678) was developed specifically for this study and tested for the first time.

METHODS The data were obtained for 11 months between May 2019 and March 2020 in the NICUs of two different hospitals in the Gaziantep province of Turkey using a single-blind randomized controlled experimental design.

Eligibilty was determined by the neonatologist based on the following inclusion criteria: 1) babies born at 26-30 weeks PMA, 2) stable clinical condition, 3) vital signs stable for at least 24 hours, 4) able to have PIOMI by the 29th or 30th week PMA, 5) required respiratory support limited to an oxyhood, Continuous Positive Airway Pressure (CPAP) and/or nasal cannula up to 2L flow, 6) APGAR scores at 1- and 5-minutes of 4 and above, 7) any race or ethnicity, 8) intraventricular hemmorhage limited to level 1 or 2; and 9) had no birth defects including facial anomolies that would impact feeding.

Sample The sample consisted of a total of 60 preterm infants all born after 26 weeks PMA with 30 each in the experimental and control group. Subjects were enrolled when they reached 29 or 30 weeks PMA and met inclusion criteria, and whose parents gave written consent.

Random assignment to groups was performed by a research assistant, who was not involved in the research but worked in the same unit as the researchers, using the online software at https://www.randomizer.org. The primary nurses were blinded to groups, and the parents stepped out during therapy to assist in blinding.

Two subjects were lost during the research period. Subject number 15 in the experimental group died on the 11th day after enrollment of causes unrelated to the intervention. Subject number 31 in the control group was intubated on the 7th day after enrollment thus became ineligable. After a subject dropped out, the next subject enrolled replaced that subject and the study was continued with the same sample size.

Data Collection Tools The data were recorded on a Data Collection Form, a Follow-up Form for Daily Procedures Applied to the Infant, a Sucking Capacity Monitoring Form. The outcome measurements required preterm baby bottles and pacifiers, measuring tape for growth measurements, a scale, a bottle and pacifier sterilization machine, a labeling machine, and preterm baby silicone bottle nipples. Sucking capacity was measured by the Yakut Manometer Measuring Suction Power (Figure 1), a pressure manometer embedded into a silicone nipple developed specifically for this study by Prof. Dr. Yavuz Yakut (International Patent Number PCT/TR2019/050678). The PIOMI intervention required a stopwatch and infant monitors and no other equipment.

Ethical Approval Approval for this research was obtained and dated 9.03.2019 from Hasan Kalyoncu University Faculty of Health Sciences, Research Ethics Committee(2019/29). To ensure correct performance of the PIOMI, the researcher trained with Dr. Brenda Lessen Knoll, the founder of PIOMI, and competency was evaluated via review of a video-recording of the researcher doing PIOMI on a preterm baby (with written consent from the parents) using the Reliability Rating Tool (13) to ensure intervention fidelity. Written permission was received from Dr. Yakut to use his manometer for measuring sucking power in this study. Written informed consent was obtained from the parents of all subjects.

Test-Retest Reliability of the Manometer Measuring Suction Power To asses the reliability of the newly developed Yakut Manometer Measuring Suction Power it was tested on 10 preterm babies who had transitioned to full oral feedings and who had written consent from the parents and who were approved by a neonatologist. Each baby sucked on the manometer nipple for a minimum of one minute of successful sucking on two separate occcasions with a 5-minute interval in between. During both measurements, the highest value the infant could reach within the first minute after the baby began to suck was documented. The average sucking power at the 1st measure was 102±22.38 mmHg, and 104.5±13.83 mmHg at the 2nd measure. The test re-test reliability coefficient between the two applications was calculated by the Intraclass Correlation Coefficient (ICC) (2.1) and found to be 0.912. An ICC value of 0.75 indicates good reliability, and above .90 is excellent (33). The obtained ICC value of above 0.90 showed that the manometer was suitable / acceptable for use in clinical measurements (34).

Application Phase The PIOMI was applied only by the trained researcher, and blind to the nursing staff in charge of care and feeding. No information about the PIOMI was shared with the general staff working in the NICU, and it was performed in the absence of the mothers, although no formal curtain was used for additional blinding. Day 1 of the study was considered the 1st day that the babies received PIOMI. The researcher applied PIOMI to the experimental group for 5 minutes per day for 14 consecutive days, 15-20 minutes before a sheduled feeding at either the 09:00 or 12:00 feeding. On the first day, the baseline sucking capacity of babies in both groups was measured before any intervention. On the following 8th, 11th and 14th days, the measures of sucking capacity were repeated and followed by oral feeding trials. Growth measures were collected on the 1st and 14th days and the day of disharge (CONSORT Flow Diagram). A separate manometer nipple was used for each baby and labeled with names and surnames. Before each use, the bottle nipple was sterilized with a bottle and pacifier sterilization machine. Routine hand-washing was excercised before and after any patient or equipment contact. Babies were monitored during both the PIOMI application and the evaluation of the sucking capacity for any negative physiological/ behavioral cues of intolerance (apnea, bradycardia, desaturation below 90%, crying, tachycardia, facial color change). If one negative cue was observed, the procedure was suspended until the baby returned to normal, and was documented. The intervention would then be conitnued the following day.

Inclusion Criteria:

Eligibilty was determined by the neonatologist based on the following inclusion criteria:

• babies born at 26-30 weeks PMA,
• stable clinical condition,
• vital signs stable for at least 24 hours,
• able to have PIOMI by the 29th or 30th week PMA,
• required respiratory support limited to an oxyhood, Continuous Positive Airway Pressure (CPAP) and/or nasal cannula up to 2L flow,
• APGAR scores at 1- and 5-minutes of 4 and above,
• any race or ethnicity,
• intraventricular hemmorhage limited to level 1 or 2; and
• had no birth defects including facial anomolies that would impact feeding.

Exclusion Criteria:

• Whose gestational age at birth was less than 26 weeks,
• had congenital disorder or birth trauma,
• had NEC,
• had RDS,
• were diagnosed with severe asphyxia,
• had intraventricular bleeding,
• had Newborn Withdrawal Syndrome,
• had Fetal Alcohol Syndrome,
• were receiving ventilator support,
• were receiving Extracorporeal Membrane Oxygenation,
• developed any complications during the follow-up period in the intervention group, whose balance status deteriorated,
• whose written and verbal permissions were obtained from their parents.

We plan to share it after it is ready for publication.

The PIOMI was applied only by the trained researcher, and blind to the nursing staff in charge of care and feeding. No information about the PIOMI was shared with the general staff working in the NICU, and it was performed in the absence of the mothers, although no formal curtain was used for additional blinding.