B064 - FORMIGONS ESTRUCTURALS EN MASSA

The extra-uterine environment that a preterm infant is born into is an unsupportive, over-stimulating and stressful environment that differs greatly from the warm, safe and calming environment of a mother’s uterus (21,28,31,32).

Sharp or loud sounds can be devastating to the preterm infant as it may result in physiological changes such as tachycardia, apnoea, tachypnoea, sudden increase in arterial blood pressure, oxygen desaturation. It may disturb sleep patterns and even cause intracranial haemorrhage (5).

Along with the cochlea, the human peripheral sensory-end organs are only completely developed by 24 weeks gestation (87), whereas the auditory pathways might only mature at 40 weeks gestation, making it one of the last systems to fully mature. It is evident that this system will still be developing in the premature infant and that auditory stimulations during this time play a big role in the development of auditory perception. Seeing as auditory stimulation inaugurates communication and social attachment during early development, it supports emotional development as well (6).

The NICU exposes the preterm infant to greater noise levels (arising from equipment as well as staff) acting as a massive stressor (52).Behavioural and structural changes could decrease sound levels in the NICU (3).

Behavioural changes include sensitising staff to the noise levels recommended and informing them on the impact it has on the infant. Sensitisation to reduce noise levels involves the encouragement of nurses to use quieter alarms, promptly silencing alarms and for staff to converse a distance from the preterm infants and not right next to the infant’s bedside. Structural changes (incubator covers, relocation of the nurses’ station, individual rooms etc.) serve as a long-

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term approach in noise abatement. It is recommended that the sound be regulated at a maximum of 50 decibels similar to the sound of light traffic or a running refrigerator (17).

Despite the availability of compelling evidence regarding the negative effects of sound and noise on the developing preterm infant, it is reported that the NDSC guidelines regarding limiting noise and sound in the NICU was not adhered to in the South African context (3,59). Sounds and noise mostly arose from ward routines, sonars, x-ray machines, telephones, suctioning and nurses’ and visitors’ voices. No evidence of sound controlling devices were reported and monitor volumes were not titrated, as staff numbers are low. The prevalence of high patient-nurse ratios seemingly results in the alarm noise levels remaining high. Staff talking loudly heard throughout the NICU was evident as well (3,6). Noises were also reported from closing incubators as well as performance procedures and multi-disciplinary teams’ ward rounds (6).

Similar to the auditory system the visual system also develops late. The visual pathway is the last sensory modality to develop and only matures at about 39 to 40 weeks after birth (3). Healthy visual development requires indirect light and colour but only after the age of 2 to 3 months. Bright light might be harmful to the preterm infant’s developing retinas (2).

Furthermore, constant light can disturb body rhythm, leading to disturbance in sleep-awake cycles and ultimately sleep deprivation. Bright light decreases attention, as it prevents the eyes from opening. A sudden light increase can lead to oxygen desaturation, which could have damaging effects on the neurodevelopment of an immature visual system. Bright light can further prolong rapid eye movement sleep. This ultimately increases physiological instability, bradycardia and apnoea (5).

The visual care mediations for the preterm infant (until 40 weeks) includes exposure to low level indirect light in order to prevent the eyes from being exposed to direct light as well as facilitation of necessary sleep cycles and diurnal rhythms. It is recommended that procedure lights be equipped with adjustable field size, direction and intensity that could assist in the protection

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from direct exposure of light to the infant’s eyes (2). Cycled lightings, as a source of visual stimulation, can be used to form diurnal rhythms in preterm infants. Diurnally (daylight) cycled lighting presents the following results in the development of the preterm infant: early transition to bottle/oral feeding, improved weight gain as well as shorter hospital stay (17).

In the South African context, it is evident that fixed florescent lights are situated in panels right above the infant bed spaces. These lights cannot be dimmed although it is reported that the lights are often switched off, except during procedures or when the multi-disciplinary team rounds are underway. In cases where preterm infants were under phototherapy lights, their eyes were covered with eye shields. Incubator covers, used to shield the infant from direct light, are not always present (6).

Furthermore, challenges that hindered the staff in the South African context from complying with best practice guidelines were identified. These challenges included ineffective equipment maintenance, staff shortages and fixed physical structuring, resulting in the infants being sleep deprived and over stimulated (6). Apart from the overstimulation of the visual and auditory systems in the NICU, this environment is often filled with noxious and unpleasant odours from hospital disinfectants and antibacterial solutions, which could have a negative effect on the preterm infant’s taste and smell sensations (17,88).

The olfactory system starts developing at six weeks of pregnancy with the foetus able to smell around 28 weeks of pregnancy (30). The olfactory system proposes the preterm infant with the mother’s scent, thus making it one of crucial senses that is needed for survival after birth. This sense reinforces bonding between the mother and her infant and empowers the preterm infant to locate the mother’s nipple to feed (6,30).

The system of taste, the gustatory system, develops from eight weeks gestation to mature around twelve weeks gestation. This is also the time during which the development of swallowing and sucking reflexes occur (3,6). Amniotic fluid swallowed by a foetus aids early chemosensory experiences. In the postnatal period, these experiences (along with the sucking reflex) enable nutrition

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seeking behaviour as well as tactile necessities of the infants (feeling secured and relaxed with the mother and exploration of the surrounding environment) (3,6).

Preterm infants are often unable to manage sucking, breathing and swallowing, making them dependent on alternative methods for feeding (cup feeding, tube feeding, bottle feeding or dropper or syringe feeding with expressed breast milk). These feeding methods keep the infant from experiencing the normal sensory input that comes from smell and taste resulting in sensory deprivation and possibly oral sensitivity in the future (17).

The presence of strong smells in the South African NICUs are reported and include the use of alcohol-based disinfectant for the staff’s hands and surface cleaning products that offer a noxious odour. On the positive side, staff accommodates the infants by using gauze and water instead of wipes during the hygiene routine (3,6). Seeing as no evidence of positive olfactory stimulation (e.g. mother’s scent on a piece of her clothing/breast milk with the infant) is present (3,6), it is clear that South African NICUs are not fully adhering to the guidelines for optimal olfactory circumstances in the NICU.