Arterial oxygen saturation in preterm infants at discharge from the hospital and six weeks later

Higher awakening threshold of preterm infants in prone position may be a risk factor for SIDS

AIM

The supine sleeping position in the prevention of sudden infant death syndrome in preterm infants is poorly understood. We aimed to investigate the effect of sleep posture on cardiorespiratory parameters and movement patterns in preterm infants close to discharge.

METHODS

This observational study included neonates born in 2022 at the University Hospital Schleswig-Holstein, Lübeck, Germany. Motion sensor data, heart rate, respiratory rate and oxygen saturation were recorded for infants with postconceptional age 35-37 weeks during sleep in the prone and supine positions.

RESULTS

We recorded data from 50 infants, born at 31 (24-35) weeks of gestation (mean(range)), aged 5.2 ± 3.7 weeks (mean ± SD), of whom 48% were female. Five typical movement patterns were identified. In the prone position, the percentage of calm, regular breathing was higher and active movement was less frequent when compared to the supine position. The percentage of calm irregular breathing, number of apnoeas, bradycardias, desaturations and vital sign changes were not influenced by position.

CONCLUSION

The prone position seems to be associated with a higher arousal threshold. The supine position appears advantageous for escape from life-threatening situations such as sudden infant death syndrome.

Effect of an Alternate Definition for a Clinically Significant Cardiopulmonary Event on Discharge

OBJECTIVE

To evaluate a precise definition of a clinically significant cardiopulmonary event (CSCPE) on the hospital length of stay (LOS), medical provider satisfaction, and discharge complications.

STUDY DESIGN

This is a single-center, observational study that included 139 infants before and 134 infants after the new definition was implemented in December 2017. Retrospective data collected November 2015 to November 2017 (before) was compared with prospective data from June 2018 to July 2020 (after). Outcome measures were the proportion of infants waiting to outgrow CSCPE, LOS, provider satisfaction with the definition, and discharge complications. Multivariate regression modeling was used to evaluate variables on LOS and postmenstrual age at discharge.

RESULTS

The proportion waiting to outgrow CSCPE decreased from 68.4% to 31.7% (P < .0001). The LOS was similar between groups; however, multivariate analysis correcting for gestational age and reason awaiting discharge estimated 3.5 days (95% CI, 1.4-5.8 days; P = .0017) decrease in LOS, and 0.92 weeks (95% CI, 0.29-1.56; P = .005) younger postmenstrual age at discharge in the after group. There was no difference in the number of readmissions or emergency room visits for apnea or deaths. Provider satisfaction improved with discharge planning after the implementation of the definition.

CONCLUSIONS

We developed an alternate definition for a CSCPE that decreased the proportion of infants waiting to outgrow a CSCPE but not LOS. There was no difference in the number of readmissions or emergency room visits for apnea or deaths, and provider satisfaction in management and discharge planning was greater.

CLINICAL TRIAL REGISTRATION INFORMATION

This study was registered under the ClinicalTrial.gov Protocol ID: 5892S-15. "The effect of standardizing the definition and approach to a clinically significant cardiopulmonary event in infants less than 30 weeks on length of stay." Recorded Nov 2017.

Cardiorespiratory Events Following the Second Routine Immunization in Preterm Infants: Risk Assessment and Monitoring Recommendations

Due to frequent cardiorespiratory events (CREs) in response to the first routine immunization (rIM), current guidelines recommend readmitting and monitoring extremely preterm infants after the second rIM, though evidence on CREs in response to the second rIM is weak. In a prospective observational study, preterm infants with an increase in CREs after the first rIM were monitored for CREs before and after the second rIM. Seventy-one infants with a median gestational age of 26.4 weeks and a median weight of 820 g at birth were investigated at a median postnatal age of 94 days. All but seven infants showed an increase in CREs after the second rIM. The frequency of hypoxemias (p < 0.0001), apneas (p = 0.0003) and cardiorespiratory events requiring tactile stimulation (CRE-ts) (p = 0.0034) increased significantly. The 25 infants (35%) presenting with CRE-ts were significantly more likely to have been continuously hospitalized since birth (p = 0.001) and to receive analeptic therapy at the first rIM (p = 0.002) or some kind of respiratory support at the first (p = 0.005) and second rIM (p < 0.0001). At a postmenstruational age of 43.5 weeks, CRE-ts ceased. Our data support the recommendation to monitor infants who fulfil the above-mentioned criteria during the second rIM up to a postmenstruational age of 44 weeks.

Cerebral oxygenation monitoring of ex-preterm infants during the infant car seat challenge test

The American Academy of Pediatrics and until recently the Canadian Paediatric Society recommend preterm infants undergo an Infant Car Seat Challenge test prior to discharge to rule out systemic oxygen desaturation when placed at a 45-degree angle in a car seat. Near-infrared spectroscopy (NIRS) provides objective measurements of the impact of systemic oxygen (SO₂) desaturation, bradycardia, or both on cerebral regional oxygen saturation (rSO₂).

Objective

To characterize baseline cerebral rSO₂ during a car seat trial in preterm infants ready for discharge.

Design/Methods

A prospective observational study was performed in 20 infants (32 ± 5 weeks [mean] at a postmenstrual age 37 ± 6 weeks [mean]). Cerebral rSO₂ was continuously monitored by placing a NIRS transducer on head during Infant Car Seat Challenge (ICSC). Failure of an ICSC was defined as two SO₂ desaturation events below 85% for more than 20 seconds or one event below 80% for 10 seconds.

Results

The lowest SO₂ was 70% with a lowest NIRS recording of 68%. Three infants failed their ICSC, with the lowest rSO₂ in these three infants being 68%, above the lowest acceptable limit of 55%. Heart rate but not SO₂ appears to influence rSO₂ over the range of cerebral oxygenation seen.

Conclusions

Baseline cerebral rSO₂ during ICSC oscillates between 68 and 90%. There were no episodes of significant cerebral oxygen desaturation in studied infants regardless of whether they passed or failed the ICSC. We postulate that former preterm infants are capable through cerebral autoregulation, of maintaining adequate cerebral blood flow in the presence of either systemic oxygen desaturation or bradycardia when they are otherwise ready for discharge.

Parent Preferences Regarding Home Oxygen Use for Infants with Bronchopulmonary Dysplasia

OBJECTIVES

To determine parent preferences for discharge with home oxygen in infants with bronchopulmonary dysplasia.

STUDY DESIGN

This was a prospective study of parents of infants born at <32 weeks' gestation with established bronchopulmonary dysplasia and approaching neonatal intensive care unit (NICU) discharge. Parents were presented a hypothetical scenario of an infant who failed weaning to room air and 2 options: discharge with home oxygen or try longer to wean oxygen. The initial scenario risks reflected a 1.5-week difference in NICU length of stay and no differences in other outcomes. Length of stay and readmission outcomes were increased or decreased until the parent switched preference. Three months after discharge, parents were asked to reconsider their preference. Differences were analyzed by χ² or Kruskal-Wallis tests.

RESULTS

Of 125 parents, 50% preferred home oxygen. For parents preferring home oxygen, the most important reason was comfort at home (79%). Forty percent switched preference when the length of stay difference decreased by 1 week; 35% switched when readmission increased by 5%. For parents preferring to stay in NICU, the most important reason was fear of taking care of the child at home (73%). Thirty-two percent switched preference when the length of stay difference increased by 1 week; 31% switched when readmission decreased by 5%. One hundred ten parents completed the 3-month follow-up; 80 were discharged with home oxygen. Seventy-eight percent would prefer home oxygen (97% who initially preferred home oxygen and 60% who initially preferred to stay in the NICU).

CONCLUSIONS

Parents weigh differences in NICU length of stay and readmission risk similarly. After discharge, most prefer earlier discharge with home oxygen. Earlier education to increase comfort with home technology may facilitate NICU discharge planning.

Heart rate, respiratory rate, apnoeas and peripheral arterial oxygen saturation in healthy term neonates during quiet sleep

AIM

This study compiled percentiles for cardiorespiratory parameters in healthy term neonates during quiet sleep.

METHODS

We enrolled 215 healthy term neonates born at Hannover Medical School, Germany, between October 2011 and March 2013. They were prospectively observed on the maternity ward at a median age of two days using six-hour recordings of pulse oximeter plethysmography, oxygen saturation, thoracic breathing movements and electrocardiogram during sleep in a supine position. We examined their heart rate, respiratory rate and oxygen saturation during quiet sleep, plus bradycardias, apnoeas lasting at least four-seconds and desaturations below 85%.

RESULTS

The 3rd, 50th and 97th percentiles were calculated as follows: heart rate 87, 112 and 133 beats per minute, respiratory rate 32, 44 and 57 per minute and oxygen saturation 94, 98 and 100%. Desaturations, apnoeas and bradycardias below 80 beats per minute were common and recorded in 54%, 98% and 30% of participants. In contrast, only 7% experienced bradycardias of less than two-thirds of the baseline heart rate and 5% experienced apnoeas exceeding 15 seconds.

CONCLUSION

Our results will facilitate the evidence-based valuation of cardiorespiratory parameters in term neonates and help validate the significance of cardiorespiratory events in preterm infants at discharge.

A graphical method for comparing nocturnal oxygen saturation profiles in individuals and populations: Application to healthy infants and preterm neonates

STUDY OBJECTIVES

Pulse-oximetry (SpO₂ ) allows the identification of important clinical physiology. However, summary statistics such as mean values and desaturation incidence do not capture the complexity of the information contained within continuous recordings. The aim of this study was to develop an objective method to quantify important SpO₂ characteristics; and assess its utility in healthy infant and preterm neonate cohorts.

METHODS

An algorithm was developed to calculate the desaturation incidence, depth, and duration. These variables are presented using three plots: SpO₂ cumulative-frequency relationship; desaturation-depth versus incidence; desaturation-duration versus incidence. This method was applied to two populations who underwent nocturnal pulse-oximetry: (1) thirty-four healthy term infants studied at 2-weeks, 3, 6, 12, and 24-months of age and (2) thirty-seven neonates born <26 weeks and studied at discharge from NICU (37-44 weeks post-conceptual age).

RESULTS

The maturation in healthy infants was characterized by reduced desaturation index (27.2/h vs 3.3/h at 2-weeks and 24-months, P < 0.01), and increased percentage of desaturation events ≥6-s in duration (27.8% vs 43.2% at 2-weeks and 3-months, P < 0.01). Compared with term-infants, preterm infants had a greater desaturation incidence (54.8/h vs 27.2/h, P < 0.01), and these desaturations were deeper (52.9% vs 37.6% were ≥6% below baseline, P < 0.01). The incidence of longer desaturations (≥14-s) in preterm infants was correlated with healthcare utilization over the first 24-months (r = 0.63, P < 0.01).

CONCLUSIONS

This tool allows the objective comparison of extended oximetry recordings between groups and for individuals; and serves as a basis for the development of reference ranges for populations.

Impairment of pulmonary diffusion correlates with hypoxemic burden in central sleep apnea heart failure patients

PURPOSE

Central sleep apnea (CSA) and Cheyne-Stokes respiration (CSR) are highly prevalent in heart failure (HF) and are linked to increased mortality. Impaired pulmonary diffusion capacity [DLCO] and [KCO]) have been suggested to play a key role in CSA-CSR pathophysiology. This study investigated the relationship between HF, CSR, DLCO and KCO in well-characterized HF patients.

METHODS

This prospective study included HF patients with CSR, all patients underwent full overnight polysomnography (PSG) and lung function testing.

RESULTS

A total of 100 patients were included (age 70.7±9.7years, 95% male, body mass index 28.9±5.3kg/m², left ventricular ejection fraction 33.5±7.7%, New York Heart Association class III 65%. DLCO and oxygenation were significantly correlated with hypoxemic burden (p<0.05). Mean oxygen saturation, oxygen desaturation, C-reactive protein level and pH were significantly associated with CSA-CSR severity (p<0.05).

CONCLUSION

The finding that lung diffusion capacity is significantly associated with hypoxemic burden in HF patients with CSA-CSR highlights the important of lung function in HF patients.

Developmental changes in sleep and breathing across infancy and childhood

Sleep and breathing are physiological processes that begin in utero and undergo progressive change. While the major period of change for both sleep and breathing occurs during the months after birth, considered a period of vulnerability, more subtle changes continue to occur throughout childhood. The systems that control sleep and breathing develop separately, but sleep represents an activity state during which breathing and breathing control is significantly altered. Infants and young children may spend up to 12 hours a day sleeping; therefore, the effects of sleep on breathing are fundamental to understanding both processes in childhood. This review summarizes the current literature relevant to understanding the normal development of sleep and breathing across infancy and childhood.

Screening for cardiopulmonary events in neonates: a review of the infant car seat challenge

The infant car seat challenge (ICSC), or period of observation in a car safety seat before discharge to monitor for episodes of apnea, bradycardia and desaturation, is one of the most common tests performed on preterm neonates in the United States. However, the utility of the ICSC to identify infants at risk for adverse cardiopulmonary events in the car seat remains unclear. Minimal evidence exists to guide clinicians in performance of this test including appropriate inclusion criteria and failure criteria. In this article, the origins of the ICSC are discussed as well as potential etiologies of desaturations and bradycardia in the car seat position. Current literature on implementation, inclusion and failure criteria, incidence of failure and data on the meaning of a 'passed' vs 'failed' ICSC are discussed. Emphasis is made on minimizing time in car seats and seated devices given concern over the risk of desaturations.

Alteration in regional tissue oxygenation of preterm infants during placement in the semi-upright seating position

We investigated whether the cerebral (rSO2-C %) and renal (rSO2-R %) tissue oxygenation of preterm infants is altered by repositioning from the supine to semi-upright position for pre-discharge car seat testing. Near-infrared spectroscopy was used to measure rSO2-C and rSO2-R, which were recorded simultaneously with vital signs in 15 preterm infants for 30 minutes in supine, 60 minutes in the semi-upright (at 45 degrees in a car seat), and 30 minutes in the post-semi-upright (supine) position. Changes in rSO2-C and SO2-R were mostly within 1 Standard Deviation (SD) of baseline mean levels in the supine position. Decrease in rSO2-C and rSO2-R (more than 1SD below baseline mean) was recorded in 26.7% and 6.6% of infants respectively, which persisted even after adjustment for variation in heart and respiratory rate, and pulse oximeter measured oxygen saturation (P, 0.0001). Re-positioning the infants from the car seat to supine position was associated with normalization of the rSO2-C. Alteration in rSO2-C and rSO2-R in a car seat was independent from the gestational and post-conception age, weight and presence of anemia. We concluded that approximately one-third of preterm infants show minor reduction of cerebral tissue oxygenation in the semi-upright (car seat) position.

Nocturnal oxygen saturation profiles of healthy term infants

OBJECTIVE

Pulse oximetry is used extensively in hospital and home settings to measure arterial oxygen saturation (SpO2). Interpretation of the trend and range of SpO2 values observed in infants is currently limited by a lack of reference ranges using current devices, and may be augmented by development of cumulative frequency (CF) reference-curves. This study aims to provide reference oxygen saturation values from a prospective longitudinal cohort of healthy infants.

DESIGN

Prospective longitudinal cohort study.

SETTING

Sleep-laboratory.

PATIENTS

34 healthy term infants were enrolled, and studied at 2 weeks, 3, 6, 12 and 24 months of age (N=30, 25, 27, 26, 20, respectively).

INTERVENTIONS

Full overnight polysomnography, including 2 s averaging pulse oximetry (Masimo Radical).

MAIN OUTCOME MEASUREMENTS

Summary SpO2 statistics (mean, median, 5th and 10th percentiles) and SpO2 CF plots were calculated for each recording. CF reference-curves were then generated for each study age. Analyses were repeated with sleep-state stratifications and inclusion of manual artefact removal.

RESULTS

Median nocturnal SpO2 values ranged between 98% and 99% over the first 2 years of life and the CF reference-curves shift right by 1% between 2 weeks and 3 months. CF reference-curves did not change with manual artefact removal during sleep and did not vary between rapid eye movement (REM) and non-REM sleep. Manual artefact removal did significantly change summary statistics and CF reference-curves during wake.

CONCLUSIONS

SpO2 CF curves provide an intuitive visual tool for evaluating whether an individual's nocturnal SpO2 distribution falls within the range of healthy age-matched infants, thereby complementing summary statistics in the interpretation of extended oximetry recordings in infants.

Sleep and respiratory physiology in children

Maturational changes of breathing during sleep contribute to the unique features of childhood sleep disorders. The clinician's ability to evaluate common disorders related to sleep in children relies on an understanding of normal patterns of breathing during sleep across the ages. This article reviews respiratory physiology during sleep throughout childhood. Specific topics include an overview of respiration during sleep, normal parameters through childhood including respiratory rate, oxygen saturation, and measures of carbon dioxide, normal patterns of apneas throughout childhood, and features of breathing during sleep seen in term and preterm infants.

Prescription of home oxygen therapy to very low birth weight infants in Germany: a nationwide survey

OBJECTIVE

There is no consensus on prescription of home oxygen therapy to infants in Germany. We hypothesized that this causes considerable variability in prescribing home oxygen to infants.

STUDY DESIGN

A structured questionnaire involving management of home oxygen therapy was sent to all German pediatric departments (n = 293).

RESULTS

Response rate was 84% (247/293). SpO2 cutoff values below which oxygen therapy was considered indicated showed a wide range (80% to 94%, mean 90%). Respondents admitting >50 very low birth weight infants annually significantly more frequently prescribed home oxygen (P < .001) and aimed for SpO2 levels closer to the physiological range than those admitting less very low birth weight infants (P = .046).

CONCLUSION

Management of pediatric home oxygen therapy is diverse in Germany. Optimal SpO2 targets have to be further investigated by controlled studies and German guidelines should be established. Until then practice should abide by existing foreign guidelines.

Pulse-oximetry screening to detect critical congenital heart disease in the neonatal intensive care unit

The current pulse-oximetry screening (POS) protocol for detection of critical congenital heart defects (CCHDs) is recommended only for newborns in well-infant and intermediate care nurseries, and there is no evidence-based protocol for infants discharged from the neonatal intensive care unit (NICU). The objectives of this study were to examine the efficacy of the current screening protocol in a NICU setting and to determine the impact of a unit protocol on the use of POS. Charts of 250 infants previous (group 1) and 250 infants after (group 2) the protocol implementation were reviewed. The results of screening test and preductal and postductal SpO₂ were recorded for screened infants. A predischarge SpO₂ value was recorded if screening was not performed. No infant in group 1 had POS. All eligible infants in group 2 received screening and passed. Preductal and postductal oxygen saturations in preterm infants at discharge were similar to saturations in late preterm and term infants. These results show that oxygen saturations at discharge in late preterm and term infants requiring admission to the NICU are similar to infants with no morbidities and that the current POS protocol can be safely used for these infants at discharge from the NICU. This study also confirms that preductal and postductal oxygen saturations at discharge in preterm infants are not different from those in late preterm and term infants. A unit protocol is likely to be more effective than relying on individual providers to ensure that all infants undergo POS for detection of CCHD.

Reference values of nocturnal oxygenation for use in outpatient oxygen weaning protocols in premature infants

OBJECTIVE

To define reference ranges for oxygen saturation (SpO(2) ) values in healthy full-term infants in the first days of life and in preterm infants off supplemental oxygen as they approach neonatal intensive care unit (NICU) discharge.

METHODS

From April 2009 to March 2010, we enrolled convenience samples of full-term infants from the newborn nursery and former preterm infants who did not require supplemental oxygen at the time of discharge from the NICU. Overnight SpO(2) and signal quality recordings were obtained and analyzed for duration of artifact-free recording time (AFRT), time (s) with SpO(2) less than several different target saturations (90-95%), and number of falls in SpO(2) by ≥4% and ≥10%.

RESULTS

We studied 102 full-term infants and 52 preterm infants. Preterm and full-term infants spent similar amounts of time less than 90%, 91%, 92%, 93%, 94%, and 95% although preterm infants had more falls in SpO(2) by ≥4% per hour of AFRT. Over 67% of term and preterm infants spent less than 6% of their time below 93%.

CONCLUSION

These data represent reference SpO(2) ranges for both preterm infants not requiring supplemental oxygen at NICU discharge and full-term infants in the first days of life. As we currently lack guidelines dictating the optimal target oxygen saturations for infants and the acceptable maximal time that they can safely spend below set target saturations, our data may serve as a guide to interpreting SpO(2) recordings of premature outpatient infants who are weaning from supplemental oxygen.

Clinical predictors and institutional variation in home oxygen use in preterm infants

OBJECTIVE

To assess home oxygen use in preterm infants, identify risk factors predicting home oxygen use, and quantify the extent of institutional variation in home oxygen use across neonatal intensive care units.

STUDY DESIGN

We conducted a retrospective cohort analysis of surviving infants of 23- to 31-week gestational age discharged home in 2009, with de-identified electronic medical record information from the Pediatrix Clinical Data Warehouse. Mixed-effects logistic regression quantified clinical risk factors and institutional variation affecting home oxygen use.

RESULTS

A total of 8167 infants were identified. Home oxygen use varied by gestational age, from 59% of infants 23 to 24 weeks gestational age to 7% of infants 29 to 31 weeks gestational age. Other risk factors included small for gestational age, congenital anomalies, mechanical ventilation in the first 72 hours, fraction of inhaled oxygen >0.4 in the first 72 hours, and patent ductus arteriosus. After adjusting for clinical risk factors, there was still a 4- to 5-fold difference in institutions' odds of home oxygen use.

CONCLUSIONS

Home oxygen use was common in infants of earlier gestational ages and infants with more severe respiratory illness. Institutional variation accounted for 4- to 5-fold variation in home oxygen use. Families should be counseled about the likelihood of home oxygen use, and prospective research must identify optimal treatment strategies for high-risk infants.

Regional tissue oxygenation in preterm born infants in association with echocardiographically significant patent ductus arteriosus

OBJECTIVE

To analyze the levels of regional tissue oxygenation in preterm infants in association with echocardiographically significant patent ductus arteriosus (PDA).

STUDY DESIGN

Preterm infants with gestational age less than 32 week were enrolled before the first dose of the pharmacological treatment for the PDA. Non-invasive near-infrared spectroscopy (NIRS) technology was utilized to measure cerebral (rSO(2)-C), renal (rSO(2)-R) and mesenteric (rSO(2-M)) tissue oxygenation for approximately 60 min. Regional fractional oxygen extraction (FOE) was calculated using simultaneously measured arterial saturation (SaO(2)). We analyzed regional tissue oxygenation and oxygen extraction, hemodynamic parameters, and demographic and clinical information in association with the size of the PDA (moderate vs large).

RESULT

Among the 38 enrolled infants, the majority were diagnosed with a large (63.2%, n=24) and the rest with a moderate-sized PDA. Infants with large and moderate PDA were comparable in terms of gestational age, study age and weight, mode of delivery and hemodynamic parameters. A significantly higher proportion of infants with a moderate PDA were mechanically ventilated as compared with those with a large PDA. We found no significant differences in the rSO(2)-C and rSO(2)-R, irrespective of the type of respiratory support. However, in infants with a large PDA on continuous nasal positive airway pressure (NCPAP), the rSO(2)-M was lower and mesenteric FOE was higher than that in mechanically ventilated neonates with a large PDA, and in those with moderate PDA irrespective of the type of respiratory support.

CONCLUSION

The PDA size did not affect cerebral and renal tissue oxygenation, but the mesenteric tissue oxygenation was decreased in infants with a large PDA on NCPAP.

An exploratory investigation of some statistical summaries of oximeter oxygen saturation data from preterm babies

Aim. To explore the potential usefulness of the mean, standard deviation (SD), and coefficient of variation (CV = SD/mean) of oximeter oxygen saturations in the clinical care of preterm babies. Methods. This was an exploratory investigation involving 31 preterm babies at 36 weeks postmenstrual age. All babies were healthy, but two were considered to be clinically unstable and required greater attention. Each baby's oxygen saturations were recorded using an oximeter and summarized by the mean, SD, and CV. The potential usefulness of each measure was assessed by its ability to distinguish the two unstable babies from the others. This was achieved using box plots and hierarchical clustering together with the Calinski-Harabasz (CH) index to quantify clustering performance (higher CH index indicates stronger clustering outcome). Results. The box plots flagged both unstable babies as outliers and none of the other babies. Successful clustering of the stable and unstable babies was achieved using the CV (CH = 72.8) and SD (CH = 63.3) but not with the mean. Conclusion. Taking the box plots and clustering results together, it seems plausible that variability might be more effective than mean level for detecting instability in oxygen saturation in preterm babies and that the combination of variability and level through the CV might be even better.

Skin conductance variability between and within hospitalised infants at rest

BACKGROUND

Various methods of pain assessment in infants have been trialled in the search for objective, specific, physiologic measures of responses to pain. Skin conductance (SC) measured in the palm of the hand or on the plantar aspect of the foot may be one such measure. SC in these sites reflects the emotional sweating due to sympathetic nerve activity. The skin conductance response (SCR), which results from filling and reabsorption of sweat in the sweat glands, has previously been suggested to be the most sensitive SC parameter of sympathetic nerve activity in response to painful stimulation.

AIM

To study SCRs within and between medically stable hospitalised infants while at rest.

METHODS

SCRs were measured in infants during at least six periods of monitoring in a maximum 48-h period. Behavioural state was recorded throughout the data collection periods.

RESULTS

SC recordings (n=91) from 15 infants during sleep showed that frequency of SCRs varied between 0 and 0.04 SCRs per second (SCRs/s), median 0.002 SCRs/s. 73% of the total variation was within-infant variation, with the remaining 27% of variation due to variation between the mean SCR values of different infants.

CONCLUSION

This pilot study contributes to establishing baseline phasic SC activity in hospitalised infants at rest by measuring SCRs. These data can be used as a reference for future studies to determine the validity and reliability of SC measurement in infants exposed to painful or stressful interventions within a neonatal unit.

Continuous positive airway pressure reduces loop gain and resolves periodic central apneas in the lamb

Continous positive airway pressure (CPAP) is used to treat infant respiratory distress syndrome and apnea of prematurity, but its mode of action is not fully understood. We hypothesised that CPAP increases lung volume and stabilises respiratory control by decreasing loop gain (LG). Experimentally induced periodic breathing (PB) in the lamb was terminated early by CPAP in a dose-dependent manner, with a control epoch of 45.4+/-5.1s at zero CPAP falling to 32.9+/-5.4, 13.2+/-4.2 and 9.8+/-3.1s at 2.5, 5 and 10 cmH(2)O, respectively (p<0.001); corresponding duty ratios (duration of the ventilatory phase of PB divided by its cycle duration) increased from 0.50+/-0.02 to 0.62+/-0.05, 0.76+/-0.06 and 0.68+/-0.08, respectively (p<0.001). Since epoch duration and duty ratio are surrogate measures of LG, we conclude that CPAP ameliorates the effects of recurrent central apneas, and perhaps mixed and obstructive apneas, by decreasing LG via increases in lung volume.

Intermittent hypoxia in supine versus side position in term neonates

Supine sleeping, recommended to prevent sudden infant death, should be started in the delivery hospital, but meets concern that neonates may exhibit more intermittent hypoxia in this position. We aimed to demonstrate that intermittent hypoxia is equally rare in supine and side position. We enrolled 609 term neonates in a crossover study. Pulse oximeter saturation (Spo2) was recorded throughout; feeding periods were excluded. The rate of desaturation events to <80%/h was the primary study variable. Four hundred seventy-six recordings fulfilled study criteria. Mean duration of recording was 4.8 h in side and 4.9 h in supine position (SD 0.8 for both). There was a mean of 0.11 desaturation events per hour in supine and 0.05 per hour in side position. Of the 118 infants with desaturation events, more had such events only in supine position (64 vs. 31 infants). For supine compared with side position, the adjusted odds ratio for at least one desaturation event was 2.0 (95% confidence interval 1.3-3.1). The lowest Spo2 value reached during these events was 56% in supine and 53% in side position. These neonates had more desaturation events while sleeping supine. We speculate, however, that this positional effect likely is too small to affect outcome.

Prolonged, documented home-monitoring of oxygenation in infants and children

RATIONALE

Although home cardiorespiratory monitors have been used for a few decades, they do not give information on oxygenation status during events. Pulse oximeters with low false-alarm rates are now available but with no standards for alarm adjustment.

OBJECTIVE

To determine, in a population of children monitored at home with a pulse oximeter, whether the chosen alarm levels could safely identify potentially significant events early on but also limit the number of alarms for non-significant events.

METHODS

Retrospective cohort study of all children monitored at home with a pulse oximeter (n = 37) between 2002 and 2007. Clinical information and Hb-O(2) saturation (SpO(2)) recordings were reviewed. Audible alarm was set-up when SpO(2) reached 85% with a delay of 5 or 10 sec.

RESULTS

A total of 24,127 hr of valid data were available for analysis. There were 13,228 events >4 sec of which 9177 (69%) were events lasting <10 sec. We determine that, with an audible alarm being triggered when SpO(2) reached 85% with no delay or a delay of 5 or 10 sec, audible alarms would have occurred at a rate of 3.6, 0.9, and 0.2 alarm/night (median), respectively. Thirteen patients needed intervention following alarms. Ten patients were readmitted to the hospital on the basis of increased frequency of alarms confirmed as true events on the recordings, but in the absence of clinical deterioration.

CONCLUSION

The monitor was able to alert parents as to potentially dangerous events while the alarm adjustment limited the number of alarms for non-significant events.

Desenvolvimento dos estados de sono na infância

Na perspectiva de descrever alguns aspectos da ontogênese e da organização dos estados de sono no primeiro ano de vida, revisou-se na literatura as alterações fisiológicas e comportamentais controladas pelas mudanças que ocorrem durante o sono nessa etapa desenvolvimental. Além disso, com fundamentação na teoria precursora do sono, expõe-se as etapas da diferenciação, a classificação e a organização temporal dos estados de sono, com vistas ao manejo favorável dos eventos ambientais, que afetam a organização do sono infantil.

Detection of previously unrecognized daytime desaturation in children with chronic lung disease

PRIMARY OBJECTIVE

The prime rationale of this research is to investigate the possible occurrence of previously unrecognized episodes of desaturation apparent in preterm infants with chronic lung disease as they freely move around a non-artificial environment.

RESEARCH DESIGN

The study comprises 58 hours of telemetric recordings of SpO2, heart rate, body movement and temperature, along with full ECG and photoplethysmographic waveforms for eight preterm subjects in their home environment. MAIN OUTCOME/RESULTS: The data is analysed for remarkable events, more particularly periods of spontaneous desaturation. Statistical results for all case studies are collated into a table along with examples of graphical analysis.

CONCLUSIONS

This study has shown that some patients are prone to episodes of hypoxemia during the course of normal daily activity or daytime sleep that would usually go unrecognized and that more effective management of supplemental oxygen treatment may be possible with continual unobtrusive monitoring.

Car seat or car bed for very low birth weight infants at discharge home

OBJECTIVE

To compare the incidence of apnea, bradycardia, or desaturation in a car seat with that in a car bed for preterm very low birth weight (< or = 1500 g) infants.

STUDY DESIGN

Infants were studied for 120 minutes in a car seat and in a car bed. Apnea (> 20 seconds), bradycardia (heart rate < 80/min for > 5 seconds), desaturation (SpO2 < 88% for > 10 seconds), and absent nasal flow were monitored.

RESULTS

We assessed 151 infants (median birth weight, 1120 g [range, 437 to 3105]; median birth gestational age, 29 weeks [24 to 34]) in both devices. Twenty-three infants (15%) had > or = 1 event in the car seat compared with 29 (19%) in the car bed (P = .4). Time to first event was similar in the car seat and car bed (mean, 54 to 55 minutes). In logistic regression analyses, bronchopulmonary dysplasia was a significant predictor for a car seat event and a lower gestational age at birth was a risk factor for a car bed event.

CONCLUSIONS

We found no evidence that an event is less likely in a car bed than in a car seat. Whichever device is used, very low birth weight infants require observation during travel.

Near-infrared spectroscopy in the detection of regional tissue oxygenation during hypoxic events in preterm infants undergoing critical care

OBJECTIVES

To determine whether pulse oximetry-detected episodes of desaturation are associated with impairment of cerebral and somatic (renal) tissue oxygenation in mechanically ventilated preterm neonates.

DESIGN

Observational cross-sectional study.

SETTING

Neonatal intensive care unit of a university-affiliated children's hospital.

PATIENTS

Ten mechanically ventilated preterm (gestational age 24-32 wks) infants.

INTERVENTIONS

In addition to the traditional monitoring of hemodynamic variables that included pulse oximetry (Sao2), near-infrared spectroscopy (NIRS) was used to evaluate the cerebral and somatic (renal) tissue oxygen saturation (rSO2C and rSO2R, respectively).

MEASUREMENTS AND MAIN RESULTS

A total of 40 rSO2C and rSO2R measurements were simultaneously recorded: 20 during hypoxic events when the Sao2 was </=80% for >/=4 secs (cases) and generally ranged between 70% and 80%, and 20 measurements when the Sao2 was >/=85% (paired controls). Additionally, the fractional oxygen extraction (FOE) from the cerebral (FOEC) and renal (FOER) tissue was calculated. All the measurements were made under steady conditions during a 2-hr period. The rSO2C, rSO2R, FOEC, and FOER among the cases (Sao2 </= 80%) and controls (Sao2 >/= 85%) were compared using the paired Student's t-test. Both rSO2C and rSO2R during the desaturation episodes were lower than in the controls (51.6 +/- 6.3% vs. 66.2 +/- 10.2%, p < .0001 and 61.1 +/- 6.8% vs. 80.1 +/- 10.0%, p < .0001, respectively). The FOEC during the hypoxic episodes was comparable with control levels but increased in renal tissue. However, during two of the desaturation episodes (10%), the rSO2C and FOEC levels (which were <44% and >0.47, respectively) may reflect compromised tissue oxygen supply.

CONCLUSIONS

In the majority of mechanically ventilated preterm neonates, the reduction in cerebral and renal tissue oxygenation associated with short periods of decreased arterial saturation to 70-80% does not significantly compromise oxygen utilization in the cerebral tissue but increases oxygen extraction in the renal tissue, which might cause ischemic tissue injury following a further reduction in oxygen delivery.

Risk of cardio-respiratory abnormalities in preterm infants placed in car seats: a cross-sectional study

BACKGROUND

Little is known about the factors that predispose to the occurrence and severity of cardio-respiratory symptoms during the placement of a prematurely born infant in a car seat. The impact of gestational age, weight at discharge and infant's pre-existing cardio-respiratory status (in the supine position) on cardio-respiratory function during pre-discharge testing in a car seat (semi-upright position) has not been investigated.

METHODS

The cardio-respiratory function of 42 preterm neonates with gestational age 24 to 35 weeks and discharge weight 1790 to 2570 grams were monitored for 45 minutes before, during, and after placement in a car seat. The occurrence of periodic breathing, apnea, bradycardia, or decreased oxygen saturation (SaO2) was analyzed.

RESULTS

Prior to the car seat testing, 15 (35.7%) infants displayed one or more abnormalities of cardio-respiratory function. During the car seat testing, 25 (59.6%) infants had periodic breathing, 33 (78.2%) had oxygen saturation <90%, 14 (33.3%) had bradycardia less than 80 beats per minute, and 35 (83.3%) had a combination of these symptoms. Infants, both with and without pre-existing cardio-respiratory abnormalities, had an almost equal probability (80% vs. 83.3%) for the development of cardio-respiratory symptoms during placement in the car seat. Weight at discharge ([less than or equal to] 2,000 grams) but not the gestational age (<28 weeks or [greater than or equal to] 28<37 weeks), was associated with either increased episodes of oxygen desaturation or the combination of cardio-respiratory symptoms that were seen during the placement of these infants in the car seat. Repositioning from the car seat to the supine position showed normalization of cardio-respiratory function in the majority (83%) of the tested infants. None of the tested clinical factors were associated with the severity of the cardio-respiratory symptoms.

CONCLUSION

Pre-discharge testing of the cardio-respiratory function of preterm infants during placement in a car seat is important for the prevention of cardio-respiratory symptoms during their transportation. However, the high risk for developing cardio-respiratory symptoms will require the consideration of an alternative mode of safe home transportation for preterm infants; especially those with a discharge weight less than 2,000 grams.

The early feeding skills assessment for preterm infants

Preterm infants develop the skills necessary to begin oral feeding as their health stabilizes and as they reach a postconceptional age that supports coordination of breathing and swallowing with oral-motor functioning. The time from initiation of oral feeding to full oral feedings (with adequate intake for growth and maintenance of physiologic stability) can vary from days to months for the preterm infant. The approach to feeding the infant during this transition period must be developmentally supportive and tailored to meet the needs of the individual. To accomplish this, caregivers--notably nurses and parents--need to communicate about the specific skills that the infant has gained, about skills that are emerging, and about skills that the infant has not yet developed. The Early Feeding Skills (EFS) Assessment is a checklist for assessing infant readiness for and tolerance of feeding and for profiling the infant's developmental stage regarding specific feeding skills: the abilities to remain engaged in feeding, organize oral-motor functioning, coordinate swallowing with breathing, and maintain physiologic stability. This article introduces the EFS.

Twelve-month prospective study of oxygen saturation measurements among term and preterm infants

BACKGROUND

Optimising home oxygen delivery in infants has important logistical and safety implications. This can be aided by having a suitable reference range of normal values for arterial oxygen saturation using pulse oximetry (SpO(2)).

OBJECTIVES

To describe oxygenation profiles in healthy preterm and term infants in relation to gestational and postnatal age, to extend reference values to guide home oxygen therapy.

STUDY DESIGN

Prospective monitoring of SpO(2) for 4 hours at 3 monthly intervals of 34 term, and 53 preterm healthy infants, took place over a 12-month period using an Ohmeda Biox 3700e pulse oximeter and data logger.

RESULTS

Group mean and 5th percentiles were used to construct cumulative frequency curves at each time interval, representing the normal reference range of SpO(2) profiles for term and preterm infants over time.

CONCLUSIONS

These data may be used to test the benefits in the home or hospital of having a reference range of normal values for cumulative SpO(2).

The Australian Safe-n-Sound Baby Safety Capsule and its effect on oxygen saturation values in infants ready for discharge home

PURPOSE

To examine the effect of Australian Safe-n-Sound Baby Safety Capsule (BSC) on oxygen saturation (SpO2) values of preterm and term infants ready for discharge home.

DESIGN

A two-group pretest/protest quasi-experimental study compared the effect of the BSC on SpO2.

SAMPLE

Thirty-nine low birth weight premature newborn infants and 19 term newborn infants ready for discharge home.

MAIN OUTCOME VARIABLE

Mean oxygen saturation values and the number of oxygen desaturation events below 90 percent.

RESULTS

The mean SpO2 values for both preterm and term infants were within the normal range (>90-100 percent) for each phase of data collection (baseline, capsule, and recovery). However, mean SpO2 values decreased from baseline during the 60 minutes spent in the BSC for the preterm infants.

The effects of flight and altitude

Increasing numbers of infants and children journey by aeroplane, or travel to high altitude destinations, for example, on holiday or as part of a population migration. Most are healthy, although increasingly children may be transported by aeroplane or helicopter specifically to obtain treatment for severe illness or injury. It is therefore useful to review the effects of altitude, and their relevance to children who undertake flights or travel to, or at high altitudes, particularly those with acute and chronic medical conditions.

Sudden unexpected deaths after discharge from the neonatal intensive care unit

The published evidence on the risk of sudden unexpected death in infants after discharge from the neonatal intensive care unit (NICU) is reviewed, together with the relevance of the various identified potentially modifiable post-natal risk factors, particularly sleeping position. Infants of low birthweight, short gestation, and those with adverse perinatal histories are at substantially increased risk of sudden infant death syndrome (SIDS), but the potential benefits from following the measures designed to reduce the risk of SIDS are proportionally greater than for term infants. The use of home apnoea monitors has not been shown to be of value in preventing SIDS, but the importance of maintaining adequate oxygenation in infants with bronchopulmonary dysplasia is emphasised. Evidence based recommendations for care of infants after discharge from the NICU with a view to reducing the risk of SIDS are presented, and do not differ significantly from those for low-risk infants.

Early NICU discharge of very low birth weight infants: a critical review and analysis

Early neonatal intensive care unit (NICU) discharge has been advocated for selected preterm infants to reduce both the adverse environment of prolonged hospital stay and to encourage earlier parental involvement by empowering parents to contribute to the ongoing care of their infant, and thereby reducing costs of care. Randomized trials and descriptive experiences of early discharge programs are critically reviewed over the last 30 years, and the key elements necessary for successful early discharge are reviewed and defined. Early discharge is clearly achievable for a large number of infants. Variations in neonatal care practices are reviewed since these variations have been documented to influence NICU stay. Management of apnea of prematurity and feeding practices is documented to significantly influence NICU length of stay, as is timing of discharge based on institutional factors. Developmentally centered care, use of nutritional supplements pre- and postdischarge, hearing screening programs, evaluation for retinopathy of prematurity, evaluation for apnea and bradycardia events, and cardiopulmonary stability while in a car seat all influence timing of discharge. Programs of early hospital discharge with home nursing and neonatologist support have been successful in lowering the length of NICU stay. However, trends in length of stay in NICUs indicate that for infants >750 g at birth over the last decade there have been insignificant reductions in length of hospital stay. Thus, because of the increase in the percentage of low birth weight infants in the US, there remain opportunities to improve on variations in care that will be translated to fewer NICU days in hospitals for selected infants. Several professional guidelines are summarized, and standards of care as related to discharge of premature infants are reviewed.

Controversy surrounding the use of home oxygen for premature infants with bronchopulmonary dysplasia

OBJECTIVE

To determine the criteria used in the current practice of neonatology for the initiation of home oxygen therapy in premature infants with bronchopulmonary dysplasia and to compare these criteria with the available literature regarding the use of home oxygen therapy.

STUDY DESIGN

Participants in the December 2000 meeting of the Vermont Oxford Network were surveyed regarding their current use of home oxygen therapy for infants with bronchopulmonary dysplasia.

RESULTS

Surveys were returned by 181 out of 297 participants. Pulse oximetry saturation (SpO2) thresholds for the initiation of home oxygen therapy varied widely from <84% to <98%. The most common threshold was <90% chosen by only 43% of the respondents. Additionally, 22% of the respondents did not initiate therapy until the oxygen saturation in room air was below 88%. Once on oxygen therapy, the target SpO2 also varied widely from >84% to >98%, with only 27% of respondents aiming for an SpO2 of >94%.

CONCLUSIONS

There is a clear lack of consensus among neonatologists regarding the initiation of home oxygen therapy for bronchopulmonary dysplasia. Furthermore, the criteria used for home oxygen therapy varies widely with the majority of neonatologists surveyed using oxygen saturation levels not supported by the literature. We speculate that a significant underutilization of home oxygen therapy exists for infants with bronchopulmonary dysplasia.

Occurrence of oxygen desaturation events during preterm infant bottle feeding near discharge

AIMS

The purpose of this study was to examine the occurrence, severity, pattern, and moderators of oxygen desaturation during preterm infant bottle feeding near the time of discharge from the neonatal intensive care unit (NICU) when fed by mothers.

STUDY DESIGN

Twenty-two very low birthweight (VLBW) infants [birthweight 1155+/-293 g, gestational age (GA) 28.1+/-2.0, postconceptional age (PCA) 36.5+/-1.6 weeks] were videotaped being bottle-fed by their mothers. Most infants (86%) were discharged within 6 days of the study. Oxygen saturation was continuously monitored and infant feeding behaviors were coded. Oxygen desaturation events (SpO(2)<90%) were identified and analyzed.

RESULTS

Infants averaged 10.8 events during feeding (range 1-28, S.D. 8.9) and spent, on average, 20% of their feeding time (range 0-70%, S.D. 17.98%) with oxygen levels below 90%. One hundred forty of the desaturation events (59%) were classified as mild (SpO(2) 85-89), 47 events (20%) were classified as moderate (SpO(2) 81-84), and 51 events (21%) were classified as severe (SpO(2)</=80). Events were evenly distributed across infants' feeding time. Receiving supplemental oxygen, beginning the feeding with a higher baseline SpO(2), and being of older PCA predicted lower percentage of feeding time with SpO(2) below 90% (R(2)=0.57). Receiving supplemental oxygen and beginning the feeding with a higher baseline SpO(2) predicted less number of desaturation events during the feeding (R(2)=0.44). Despite similar baseline SpO(2) levels, infants who were on supplemental oxygen had 50% less oxygen desaturation events and spent 33% less time with SpO(2) less than 90%.

CONCLUSION

VLBW infants continue to have desaturation events during feeding when fed by their mothers near the time of discharge. Further research is needed to understand the effect of hypoxemia on the preterm infant's development of oral feeding skills, to study the effects of supplemental oxygen during feeding, and to further develop interventions to minimize desaturation during feeding.

Periodic breathing and oxygen saturation in preterm infants at discharge

OBJECTIVE

Periodic breathing (PB) is a common respiratory pattern in preterm infants. Our aim was to determine the influence of PB on the pattern of oxygenation in preterm infants with significant PB at discharge from hospital.

STUDY DESIGN

Overnight 12-hour recordings of arterial O(2) saturation (SpO(2)), impedance breathing movement, nasal thermistor signals for airflow, and heart rate were performed in all preterm infants < or = 34 weeks' gestational age at birth, prior to hospital discharge. Infants had recovered from their neonatal complications and were not receiving methylxanthines or supplemental oxygen. Data from 28 infants who had significant PB (> or = 5% of quiet time artifact free) were further analyzed. Gestational age at birth was (median, range) 32 (27-34) weeks, and gestational age at recording was 35 (33-37) weeks.

RESULTS

The baseline SpO(2) was 98% (92-100%). During PB, all infants had episodes when SpO(2) fell > or = 5%, and all except one had episodes when SpO(2) was < 90%. Sixty episodes of prolonged desaturation (SpO(2) < or = 80% for >/ or = 4 seconds) were recorded in 10 infants: 31 occurred during PB, 16 during hypopnea, 10 during apnea, and 3 occurred in the absence of these breathing patterns. During PB, nine infants (32%) had 1 to 13 episodes of prolonged desaturation, lasting 9 (4-76) seconds.

CONCLUSION

We conclude that PB is a common cause of prolonged desaturation in preterm infants at discharge.

Desaturation events in neonates during mechanical ventilation

This study examines the accuracy of oxygen saturation measured by Nellcor N200 pulse oximetry (SpO2) compared with arterial oxygen saturation (SaO2) measured through a three-wavelength fiberoptic umbilical catheter in 10 neonates who needed mechanical ventilation. Real-time SaO2 was validated with a reference method every 4 hours. Oxygen saturation readings (SaO2 and SpO2), along with pulse rate and pulsation, were recorded continuously every second through a computer. Concurrent care events and neonatal responses were recorded. Data were completed on 10 neonates who had an umbilical arterial catheter. Desaturation events (<90%) as measured by both SaO2 and SpO2 were described and compared. A total of 959 desaturation events occurred during an average of 51 hours of monitoring per subject. Of these events, 63% were associated with frozen SPO2 readings, and 18% of frozen readings occurred when SaO2 was <90%. Bias for SpO2 compared with SaO2 was +5.03%, with 5.6% of the readings outside the range of two standard deviations. However, 67% of the readings exceeded the 4% difference criterion between measurements. Future studies need to examine the desaturation events in relation to oxygenation status as measured by different methods.

Respiratory instability of term and near-term healthy newborn infants in car safety seats

OBJECTIVE

Premature infants who are discharged from intensive care nurseries are known to be at increased risk for apnea, bradycardia, and oxygen desaturation while in the upright position. These small infants also do not fit securely in standard infant car seats. Because of these problems, the American Academy of Pediatrics recommends a period of observation in a car seat for all infants who are born at <37 weeks' gestation. It is not clear whether this recommendation should apply to the minimally preterm infants (born at 35-36 weeks' gestation) who are healthy at birth and are hospitalized in the normal newborn nursery. The objective of this study was to evaluate the respiratory stability and safety requirements of healthy, minimally preterm infants in car seats compared with term infants.

METHODS

Fifty healthy, nonmonitored, preterm infants (mean gestational age: 35.8 +/- 0.6 weeks) and 50 term infants (mean gestational age: 39.5 +/- 1.4 weeks) were recruited from a level I newborn nursery in a community hospital. Appropriateness of car seat fit was documented for each infant. Heart rate, respiratory rate, and pulse oximetry were evaluated while infants were supine and in their car seats. Apneic and bradycardic events were recorded in addition to a continuous recording of oxygen saturation values.

RESULTS

Twenty-four percent of preterm and 4% of term newborn infants did not fit securely into suitable car seats despite the use of blanket rolls. Mean oxygen saturation values declined significantly in both preterm and term infants from 97% in the supine position (range: 92%-100%) to 94% after 60 minutes in their car seats (range: 87%-100%). Seven infants (3 preterm and 4 term) had oxygen saturation values of <90% for longer than 20 minutes in their car seats. Twelve percent of the preterm infants (95% confidence interval: 4.5%-24.3%) but no term infants had apneic or bradycardic events in their car seats.

CONCLUSIONS

Our data support the current American Academy of Pediatrics recommendations that all infants who are born at <37 weeks' gestation, including those who are admitted to level I community hospitals, be observed for respiratory instability and secure fit in their car seats before hospital discharge. Because lowering of oxygen saturation values was seen uniformly in all newborn infants, car seats should be used only for travel, and travel should be minimized during the first months of life.

Back to sleep: is there room in that crib for both AAP recommendations and developmentally supportive care?

This article offers one institution's approach to implementation of the recommendations for infant sleep positioning as set forth by the American Academy of Pediatrics. The guidelines are directed toward healthy infants in the first year of life, a population not always encountered by the neonatal nurse. The guidelines focus on supine sleep position and the minimization of additional bedding, both of which can be challenging when contrasted with accomplishing supportive positioning and the goals of developmentally supportive care for ill or preterm infants. A multidisciplinary task force was formed to consider this challenge. The outcome is an evidence-based policy that is presented as an example for other clinicians. The policy addresses the following major components: sleep position with specific clinical exceptions, the use of bedding materials, play position during awake states, and parent education with preparation for discharge. The article also outlines the process by which the task force plans to implement and evaluate necessary practice changes.

Haemodynamic effects of altering arterial oxygen saturation in preterm infants with respiratory failure

AIMS

To examine the haemodynamic effects of brief alteration in arterial oxygenation in preterm infants with respiratory failure.

METHODS

Eighteen preterm infants with respiratory failure, aged 9-76 hours, underwent detailed Doppler echocardiographic assessment at 86%, 96%, and 100% SaO2, achieved by altering the FIO2. Sixteen were receiving intermittent positive pressure ventilation, median FIO2 0.45 (0.20-0.65), median mean airway pressure 12 cm H2O (0-20). SaO2 was stable for 15 minutes at each stage. Four parameters of pulmonary arterial pressure were measured: peak velocity of tricuspid regurgitation and peak velocity of left to right ductal flow, TPV:RVET ratio and PEP:RVET ratio, measured at the pulmonary valve, along with flow velocity integrals at the aortic and pulmonary valves, and systemic arterial pressure. Ductal size was graded into closed, small, moderate, large with imaging, pulsed and continuous wave Doppler.

RESULTS

Between 86% and 96% SaO2, there were no consistent changes, but in three of the 12 with a patent ductus arteriosus (PDA) there was ductal constriction, with complete closure in one. Between 96% and 100% SaO2, peak ductal flow velocity rose significantly in four of eight with a PDA. Ductal constriction occurred in four infants; in three this was associated with a significant fall in aortic flow integral and a rise in aortic pressure (4-6 mm Hg). Overall, 11 infants went from 86% to 100% SaO2 and pulmonary arterial pressure fell significantly in seven.

CONCLUSION

A brief rise in SaO2 within the range maintained by most neonatal units can cause significant ductal constriction. The fall in pulmonary arterial pressure with 100% SaO2 seen in most infants was associated with a fall in pulmonary blood flow (or no change), rather than a rise, indicating that the dominant haemodynamic effect was ductal constriction rather than pulmonary vasodilation.