Effect of a rocking bed on apnoea of prematurity

Effects of semi-upright swings on vital signs in NICU infants

BACKGROUND

The aim of this study was to compare the impact of a semi-upright swing with a standard crib on vital signs in infants in the neonatal intensive care unit (NICU).

METHODS

We performed a within-subjects' comparison of vital signs of NICU infants corrected to ≥34 weeks of gestation and placed in the supine position versus the semi-upright position in a swing. The primary outcome was the mean oxygen saturation, and the secondary outcomes were the mean heart rate, the proportion of time with oxygen saturation (SpO₂) <90%, and respiratory rate.

RESULTS

Of the 65 infants, 34 (57%) were male and 32 (50%) were black. The mean ± SD gestational age at birth was 32.4 ± 5.1 weeks. In all, 40% were on noninvasive respiratory support. There were no significant differences in oxygen saturation, heart rate, time with oxygen desaturation defined by SpO₂ < 90%, or respiratory rate between the supine and semi-upright positions. A higher risk of desaturations was observed in infants without respiratory support (RR, 1.24, 95% CI, 1.15-1.33) and low-birth-weight infants (RR, 1.55, 95% CI, 1.42-1.69).

CONCLUSIONS

The placement of infants in a semi-upright swing resulted in no discernible differences in averaged vital signs compared to the supine position in NICU infants.

IMPACT

We identified no significant differences in averaged oxygen saturation, heart rate, or respiratory rate among NICU infants placed in a semi-upright swing compared to the supine position. Desaturation events occurred at a higher frequency in low-birth-weight infants and those on room air when placed in the swing, although none required oxygen supplementation. The results from the current study support that it is probably safe to use semi-upright swings in the NICU environment, although additional studies are necessary for generalization to the unmonitored home environment.

Anthropo-Mechanical Cradles: A Multidisciplinary Review

Domestic cradles are beds that are movable but non-mobile for babies up to five months of age. The "anthropo-mechanical" cradle simulates the physiological movement of the human body. The article reviews scientific literature discussing the impacts of swinging on infants, provides classifications of all currently used cradles due to how the child moves, and briefly describes modern technologies within cradle automation. This made it possible to calculate and propose safe motion parameters within mechatronic cradles. The main conclusions of the article are as follows: (1) the scientific literature reports the beneficial effects of harmonic movement on a child, (2) motion analyses substantiating the classifications of all cradles into six types (tilting, yawing, hammock, Sarong, swing, and surging cradle; the classification criterion included the nature of the cradle movement in relation to the planes and anatomical axes of the child's body), (3) modern technologies allowing for the use of movement with thoughtful parameters, thus, safer for a child, (4) movement within the parameters similar to the motion and speed passively performed by the child in the womb while a mother is walking was considered beneficial and safe, and (5) the use of advanced technology allows for the possibility to devise and create an automatic mechatronic cradle with a child-safe motion. Future innovative anthropo-mechanical cradles that follow physiological human motion parameters can be used safely, with a vertical amplitude ranging from -13 to + 15 mm and a frequency of up to 2 Hz.

Sensory stimulation for apnoea mitigation in preterm infants

Apnoea, a pause in respiration, is ubiquitous in preterm infants and are often associated with physiological instability, which may lead to longer-term adverse neurodevelopmental consequences. Despite current therapies aimed at reducing the apnoea burden, preterm infants continue to exhibit apnoeic events throughout their hospital admission. Bedside staff are frequently required to manually intervene with different forms of stimuli, with the aim of re-establishing respiratory cadence and minimizing the physiological impact of each apnoeic event. Such a reactive approach makes apnoea and its associated adverse consequences inevitable and places a heavy reliance on human intervention. Different approaches to improving apnoea management in preterm infants have been investigated, including the use of various sensory stimuli. Despite studies reporting sensory stimuli of various forms to have potential in reducing apnoea frequency, non-invasive intermittent positive pressure ventilation is the only automated stimulus currently used in the clinical setting for infants with persistent apnoeic events. We find that the development of automated closed-looped sensory stimulation systems for apnoea mitigation in preterm infants receiving non-invasive respiratory support is warranted, including the possibility of stimulation being applied preventatively, and in a multi-modal form. IMPACT: This review examines the effects of various forms of sensory stimulation on apnoea mitigation in preterm infants, namely localized tactile, generalized kinesthetic, airway pressure, auditory, and olfactory stimulations. Amongst the 31 studies reviewed, each form of sensory stimulation showed some positive effects, although the findings were not definitive and comparative studies were lacking. We find that the development of automated closed-loop sensory stimulation systems for apnoea mitigation is warranted, including the possibility of stimulation being applied preventatively, and in a multi-modal form.

The Importance of Rhythmic Stimulation for Preterm Infants in the NICU

The fetal environment provides the fetus with multiple potential sources of rhythmic stimulation that are not present in the NICU. Maternal breathing, heartbeats, walking, dancing, running, speaking, singing, etc., all bathe the fetus in an environment of varied rhythmic stimuli: vestibular, somatosensory, tactile, and auditory. In contrast, the NICU environment does not offer the same proportion of rhythmic stimulation. After analyzing the lack of rhythmic stimulation in the NICU, this review highlights the different proposals for vestibular and/or auditory rhythmic stimulation offered to preterm infants alone and with their parents. The focus is on the beneficial effects of auditory and vestibular stimulation involving both partners of the mother-infant dyad. A preliminary study on the influence of a skin-to-skin lullaby on the stability of maternal behavior and on the tonic emotional manifestations of the preterm infant is presented as an example. The review concludes with the importance of introducing rhythmic stimulations in the NICU.

Swinging and Rocking: Two Millennia of Debating the Cradle

In most societies, devices evolved to enhance the mother's working capacity. This article depicts the cradle's development in some countries and delineates the scientific debate that led to its demise in the 19th century. A few basic forms of infant cots survived the centuries from antiquity: the carrying board, trough, hammock, sling, transverse rockers, and forward rockers. Romans discerned 2 types: the cuna stood on the floor and was moveable by wooden rockers. Lecti pensiles were suspended beds. Cradleboards of Native Americans revealed remarkable variety of shapes and decorations. The cradle's hood was a 16th century development, intended to protect the baby's face from flies, sunlight, and the evil eye. Already in the second century CE, Galen mentioned controversies about rocking. A fervent debate began in the 18th century. Propagators reasoned that rocking perpetuates habitual fetal movement, exercises the child, and avoids the need for somniferous drugs. Opponents claimed that rocking is dangerous, producing an unnatural sleep harmful to the brain, and impeding milk digestion. In the 20th century, cradles were replaced by pushchairs and prams, but they did not disappear. Despite centuries of debate, robust studies have never been conducted, and it remains unclear whether rocking has any benefit or harm for the infant.

Preterm Neurodevelopmental Outcomes Following Orosensory Entrainment Intervention

Previous research indicates that the NTrainer, a pressurized pacifier programmed to produce pulsed pneumotactile stimulation during gavage feeds, has been found to facilitate non-nutritive suck development and shorten the length of hospital stay when used in the Neonatal Intensive Care Unit (NICU). Four groups of children, including infants of diabetic mothers (IDM), healthy controls (HI), and those with respiratory distress syndrome (RDS), or chronic lung disease (CLD), were randomly assigned to an NTrainer therapy or sham 'control' condition when in the NICU. At 30 months of age, 113/223 study participants were assessed using standardized language, motor, and cognitive assessments. No significant group differences were evident between the NTrainer and sham groups in language, motor, or cognitive functioning. The NTrainer did not improve nor adversely impact language, cognition, or motor outcomes.

The effects of vestibular stimulation rate and magnitude of acceleration on central pattern generation for chest wall kinematics in preterm infants

OBJECTIVE

To examine the role of vestibular inputs on respiratory and oromotor systems in healthy preterm infants.

STUDY DESIGN

A total of 27 preterm infants were quasi-randomly assigned to either the VestibuGlide treatment or control groups. VestibuGlide infants were held in a developmentally supportive position, given a pacifier and received a series of vestibular stimuli, counterbalanced across rate and acceleration conditions, 15 min 3 times per day for 10 days. The control infants were also held in a developmentally supportive position, given a pacifier for 15 min 3 times per day for 10 days but did not receive the VestibuGlide stimulation.

RESULT

A multi-level regression model revealed that treatment infants increased their respiratory rate in response to vestibular stimulus, and that the highest level of vestibular acceleration delivered to the infants (0.51 ms(-2)) resulted in a significant increase in breaths per minute.

CONCLUSION

Vestibular stimulation delivered to preterm infants before scheduled feeds effectively modulates respiratory rate and resets the respiratory central pattern generator.

Stabilizing immature breathing patterns of preterm infants using stochastic mechanosensory stimulation

Breathing patterns in preterm infants consist of highly variable interbreath intervals (IBIs) that might originate from nonlinear properties of the respiratory oscillator and its input-output responses to peripheral and central signals. Here, we explore a property of nonlinear control, the potential for large improvement in the stability of breathing using low-level exogenous stochastic stimulation. Stimulation was administered to 10 preterm infants (postconceptional age: mean 33.3 wk, SD 1.7) using a mattress with embedded actuators that delivered small stochastic displacements (0.021 mm root mean square, 0.090 mm maximum, 30-60 Hz); this stimulus was subthreshold for causing arousal from sleep to wakefulness or other detectable changes in the behavioral state evaluated with polysomnography. We used a test-retest protocol with multiple 10-min intervals of stimulation, each paired with 10-min intervals of no stimulation. Stimulation induced an approximately 50% reduction (P = 0.003) in the variance of IBIs and an approximately 50% reduction (P = 0.002) in the incidence of IBIs > 5 s. The improved stability of eupneic breathing was associated with an approximately 65% reduction (P = 0.04) in the duration of O(2) desaturation. Our findings suggest that nonlinear properties of the immature respiratory control system can be harnessed using afferent stimuli to stabilize eupneic breathing, thereby potentially reducing the incidence of apnea and hypoxia.

[Sensory stimulations for the treatment of idiopathic apneas of prematurity]

Idiopathic apneas of prematurity remain an alarming problem in neonatology. Long-term effects on neurological development cannot be excluded. Two principal treatments are currently applied to prevent apneic attacks: analeptics (methylxanthines and doxapram) and continuous positive airway pressure. Several studies suggest the use of sensory stimulations for curative or preventive treatments. Protocols of tactile, kinesthetic and auditory stimulations are described and their respective efficacy is discussed. We also resume a recent preliminary study which suggested the use of an olfactory stimulation as preventive treatment. A beneficial effect, specifically on apnea associated with severe bradycardia, was observed. Complementary studies are necessary to confirm the benefit of such sensory stimulations for apneas of prematurity, and, if so, to allow clinical applications.

Massage therapy and sleep behaviour in infants born with low birth weight

This study attempts to evaluate the impact of massage therapy on sleep behaviour in infants born with low birth weight (LBW) in St. Petersburg, Russia. Fifty infants (22 boys, 28 girls) who were born in St. Petersburg between 2000 and 2002 and defined as LBW babies (<2500g at birth) were enrolled onto the study at the age of 2 months. Of these, 41 (19 boys, 22 girls) were light and pre-term infants (gestational age < or =36 weeks), and 9 (3 boys, 6 girls) born light at term. The control group consisted of 50 healthy infants born with LBW who were cross-matched with an experimental group of babies and controlled for gender, gestational age, weight and date of birth. The groups were also matched for proximal geographical distribution in the city. Babies in the experimental group were assigned massage intervention therapy that include gentle rubbing, stroking, passive movements of the limbs and other means of kinaesthetic stimulation performed by professionals until the infant is 8 months old. The findings suggest that 8-month-old LBW infants who received massage intervention were less likely to snore during sleep, required less feeding on waking-up at night, and appeared more alert during the day. These apparent correlations remained significant after adjustment was made for major potential confounders. No statistically significant difference was found in sleep behaviour between LBW infants exposed to massage therapy who were either born pre-term or at term. It is suggested that massage may be a valuable approach to improve quality of sleep and reduce sleep-disordered breathing in infants born with LBW. It is acknowledged that whilst this study does not represent a large sample, it is felt that the findings suggest further investigation and offer an insight into an area previously relatively unexplored.

Temporal trends of cardiac and respiratory responses to ventilatory challenges in congenital central hypoventilation syndrome

Congenital central hypoventilation syndrome (CCHS) patients exhibit respiratory deficits to ventilatory challenges, diminished breathing drive during sleep, and reduction of respiratory-related heart rate variation, but at least partially preserved peripheral chemoreception. We hypothesized that integration of afferent activity with respiratory motor output is deficient in CCHS, rather than chemoreceptor failure, and that examination of trends in heart and breathing rates and variabilities following ventilatory challenges may clarify the deficient mechanisms. Twelve children with CCHS and 12 age- and gender-matched control cases were subjected to hyperoxic hypercapnic, poikylocapnic hypoxic, and hyperoxic challenges while supine. Heart and respiratory rates and variabilities during 60-s baseline and 120-s challenge periods were assessed. Hypoxia and hypercapnia enhanced breathing rate in control subjects; in CCHS cases, the rise differed during hypercapnia and did not occur to hypoxia. Hyperoxia showed initial transient patterns in breathing rate that differed between groups. A heart rate increase to hypoxia and late decline to hyperoxia were muted in CCHS patients. In hypercapnia, heart rate followed similar rising patterns in both groups. Overall CCHS heart rate variability was lower in baseline and challenge periods, principally due to diminished respiratory-related variation, especially during hypercapnia. No heart rate variability group differences emerged in hypoxia, and only a late increase for CCHS cases developed in hyperoxia. The findings indicate retention of aspects of chemoreceptor sensitivity in CCHS cases. The heart rate alterations to ventilatory challenges suggest specific compensatory responses of a slower nature remain intact in CCHS, whereas other rapidly changing components are deficient.

Treatment of apnea of prematurity

In the last decade, knowledge regarding the neurodevelopment and functional aspects of the respiratory centers during postnatal maturation has increased substantially. However, an increase in such knowledge has not provided a basis for change in practice. The diagnosis of apnea of prematurity (AOP) is one of exclusion. All causes of secondary apnea must be ruled out before initiating treatment for AOP. Treatment will depend on the etiology as well as effectiveness and tolerability of the treatment by the patient. The primary goal of any treatment of AOP is to prevent the frequency of apnea lasting >20 seconds, and/or those that are shorter, but associated with cyanosis and bradycardia. The clinical management of AOP is not much different today than it was two decades ago, with pharmacologic and nonpharmacologic treatment options remaining the mainstay of therapy. Methylxanthines are still the most widely used pharmacologic agents. Due to the wider therapeutic index of caffeine and ease of once daily administration, it should be the preferred agent. Doxapram, or nonpharmacologic treatment measures such as nasal continuous positive airway pressure, may be considered in infants who are unresponsive to methylxanthine treatment alone. Treatment should be continued until there is complete resolution of apnea, and for some time thereafter. The choice of method for weaning treatment remains one of individual physician preference. Discharge from hospital after apnea requires close monitoring and some infants will require home apnea monitors. The decision to provide a home apnea monitor should be individualized for each patient, depending on the effectiveness of treatment and clinical response.

Kinesthetic stimulation for treating apnea in preterm infants

BACKGROUND

This section is under preparation and will be included in the next issue.

OBJECTIVES

Main question: in preterm infants with apnea, does the use of kinesthetic stimulation lead to clinically important reductions in clinical apnea and bradycardia (>50% reduction in number of episodes), use of mechanical ventilation (IPPV) or continuous positive airways pressure (CPAP), and neurodevelopmental disability, without clinically important side effects.

SEARCH STRATEGY

The standard search strategy of the Neonatal Review Group was used. This included searches of the Oxford Database of Perinatal Trials, Cochrane Controlled Trials Register, MEDLINE, previous reviews including cross references, abstracts, conferences, symposia proceedings, expert informants, and journal handsearching mainly in the English language.

SELECTION CRITERIA

All trials using random or quasi-random patient allocation in which kinesthetic stimulation in preterm infants was compared to placebo or no treatment for apnea of prematurity were included.

DATA COLLECTION AND ANALYSIS

Standard methods of the Cochrane Collaboration and its Neonatal Review Group were used with separate evaluation of trial quality, data extraction by both authors and synthesis of data using relative risk and weighted mean difference. As all three trials were crossover trials, the data were extracted from all exposure periods and combined where appropriate. Measures of severity of apnea as well as the response to treatment were consistent with an evaluation of 'clinical apnea', as defined by the American Academy of Pediatrics (Nelson 1978).

MAIN RESULTS

Three crossover studies (Korner 1978, Tuck 1982 and Jirapaet 1993) were identified that compared a form of kinesthetic stimulation to control for the treatment of apnea of prematurity. Clinically significant apnea: None of the three studies showed an important reduction (>50%) in clinical apnea. Using a lower threshold (>25%), the study by Korner 1978 found less apnea and bradycardia in infants receiving kinesthetic stimulation. Tuck 1982 demonstrated reductions in the frequencies of apneas (> 12 seconds) associated with bradycardia (< 100 bpm), apneas associated with hypoxia (TcP02 < 50 mmHg), and apneas requiring stimulation in infants on the rocking bed. Individual patient data were not available from the author to determine if there was an important reduction in clinical apnea. No outcome could be extracted from the study by Jirapaet 1993 that was consistent with the definition of clinically important apnea. Other events: No significant differences were found in the incidence of infants requiring resuscitation, IPPV, CPAP or respiratory stimulants whilst receiving treatment. Adverse events such as death, intraventricular hemorrhage and neurodevelopmental follow up were not reported.

REVIEWER'S CONCLUSIONS

There is insufficient evidence to recommend kinesthetic stimulation as treatment for clinically significant apnea of prematurity. Previous reviews have suggested that kinesthetic stimulation is not effective at preventing apnea of prematurity (Henderson-Smart and Osborn 1998) and is not as effective as theophylline at treating clinically significant apnea of prematurity (Osborn and Henderson-Smart 1998).

Randomized clinical trial of an oscillating air mattress in preterm infants: effect on apnea, growth, and development

To investigate claims that oscillating mattresses reduce apnea of prematurity and improve growth and neurobehavioural development, we performed a randomized clinical trial using a predetermined sample size. Preterm infants weighing from 750 to 1750 gm at birth were randomly assigned, by 250 gm strata, to either a conventional mattress (n = 63) or to an air mattress (n = 59) oscillating at 14 to 16 regular pulses per minute. Infants remained on the oscillating air mattress for at least 7 days or until 34 weeks postmenstrual age. Apneic episodes occurred and required treatment equally in the two groups; this lack of an effect was seen for both sexes and all weight groups. Both weight and energy intake were similar. Neurobehavioral development as shown by sleep state, habituation testing, and behavioral assessment at term, 3, 6, and 12 months was similar in the two groups. There was no difference in the incidence of neurologic abnormalities. We conclude that an oscillating air mattress has no prophylactic value in reducing apnea and does not enhance growth and development.