***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: STUDY OBJECTIVE To describe the physiologic changes and to evaluate the safety of placing pediatric patients with acute lung injury ( ALI ) prone for 20 h/d during the acute phase of their illness . DESIGN Single-center prospect i ve case series . SETTING Tertiary-level pediatric ICU . PATIENTS Consecutive patients with bilateral pulmonary parenchymal disease requiring intubation and mechanical ventilation with a PaO(2)/fraction of inspired oxygen ( FIO(2 ) ) ratio < /= 300 mm Hg . INTERVENTIONS Patients were enrolled as soon as possible after meeting criteria and were placed in a prone position for 20 h/d daily until clinical improvement or death occurred . MEASUREMENTS AND RESULTS Twenty-five pediatric patients who had ALI/ARDS , ranging in age from 2 months to 17 years , were placed in a prone position within 19 h of meeting the study criteria for a median time of 4 days , which accounted for 47 % of their time receiving mechanical ventilation . Eighty-four percent of patients ( n = 21 ) were categorized as overall responders to prone positioning because they experienced more days of increases of > /= 20 mm Hg in PaO(2)/FIO(2 ) ratio or a decrease of > /= 10 % in oxygenation index when shifted from a supine to a prone position during the study period . During the 107 patient-days and 214 positioning cycles , no critical incidents occurred . Furthermore , no patient experienced a persistent decrease in oxygen saturation as measured by pulse oximetry ( SpO(2 ) ) of > 10 % from values obtained when in the supine position , failed to keep their SpO(2 ) at > 85 % , or experienced an increased respiratory rate of > 40 breaths/min when prone . Using the COMFORT score , patients were objective ly rated to be equally comfortable in both the supine and prone positions . Patients also were able to resume spontaneous ventilation and to progress toward endotracheal extubation while in the prone position . Iatrogenic injury associated with prolonged prone positioning included stage II pressure ulcers in six patients ( 24 % ) . CONCLUSIONS The pediatric patients in this series demonstrated improvements in oxygenation without serious iatrogenic injury after prone positioning . This study provides a foundation for a prospect i ve r and omized study investigating the effect of early and repeated prone positioning on clinical outcomes in pediatric patients with ALI OBJECTIVE To compare the effects of supine and prone positions on oxygen saturation ( SpO(2 ) ) , desaturation episodes ( SpO(2 ) < 90 % and > or= 20 seconds ) , and motor activity in ventilated preterm infants during their first postnatal week . DESIGN With use of a crossover design , we r and omly assigned infants to a supine/prone or prone/supine position sequence . Infants were placed in each position for 2 hours . A stabilization period of 10 minutes before observation of each position was allowed . During the protocol , care procedures were kept minimal and ventilator setting s remained unchanged . SETTING Neonatal intensive care units at 2 tertiary care centers in Taiwan . SAMPLE The sample consisted of 28 infants receiving mechanical ventilation who were 25 to 36 weeks ' gestation , without known congenital abnormalities , within 7 postnatal days of birth , and were not receiving sedation . RESULTS When prone , infants had higher SpO(2 ) , fewer episodes of oxygen desaturation , and less motor activity than when supine . No significant differences in duration of SpO(2 ) less than 90 % , 85 % , and 80 % were found between the 2 positions . Seventy-four percent of desaturation episodes were associated with vigorous motor activity and crying . CONCLUSION The prone position results in less motor activity and may stabilize oxygenation for ventilated preterm infants . This may conserve energy and decrease complications of hypoxia for sick preterm infants Fourteen intubated infants recovering from neonatal respiratory disease had arterial blood gases and lung mechanics measured in the supine position and in two variants of the prone position . Prone positioning result ed in significant increases in mean ( + /- SEM ) arterial oxygen tension ( Pa(o2 70.4 + /- 2.5 to 81.1 + /- 4.4 mm Hg ) , dynamic lung compliance ( 1.7 + /- 0.24 to 2.55 + /- 0.37 ml/cm H2O ) , and tidal volume ( 8.6 + /- 1.0 to 10.5 + /- 1.2 ml ) when all prone values were compared to supine values . Prone positioning with the abdomen protruding freely , when compared to all supine values , was associated with significantly increased dynamic lung compliance and tidal volume . Values for prone-abdomen free were not significantly different from values for prone-abdomen restricted . This suggests that there are clinical benefits from prone positioning in neonates recovering from respiratory disease Objectives : Gastroesophageal reflux and aspiration can occur in premature infants who are supported with mechanical ventilation . The relation between physical positioning and gastric aspiration in ventilated infants has not been studied . Pepsin measured in tracheal aspirate ( TA ) emerged as a specific marker for aspiration . The objective of our study was to assess pepsin in TA of ventilated infants at 2 different positions : supine and right lateral . Methods : We conducted a r and omized controlled trial on premature infants who were enterally fed and supported with mechanical ventilation . Patients were r and omized into intervention and control groups . In the intervention group , infants were placed supine for 6 hours before a sample of TA was obtained . A second sample was collected 6 hours later while lying in the right lateral position . In the control group , the 2 sample s of TA were obtained while infants remained in the supine position during the entire study time . Pepsin in TA was measured while blinded to the group assignment . Results : A total of 34 patients were enrolled and r and omized to intervention ( n = 17 ) and control ( n = 17 ) groups . Gestational age was 32.7 ± 2.7 weeks , and birth weight was 1617 ± 526 g ; both groups had similar demographic and clinical characteristics . Pepsin concentration did not differ between groups at baseline . In the intervention group , pepsin concentration significantly declined from 13 ng/mL ( interquartile range [ IQR ] 11.9–38.7 ) to 10 ng/mL ( IQR 7–12 ; P < 0.001 ) , whereas it did not change in the control group ( P = 0.42 ) . Conclusions : The right lateral positioning is associated with decreased TA pepsin . The implication s of the present study on hospital practice and clinical outcomes need further investigations Objective . To assess whether the recommendations that infants  sleep supine could have adverse consequences on their motor and mental development . Design . A prospect i ve study of infants , delivered before , during , and after the Back to Sleep Campaign in the United Kingdom , followed to 18 months of age . Subjects . The children were participants of the Avon Longitudinal Study of Pregnancy and Childhood born to mothers resident in the three former Bristol-based health districts of Avon , with expected date of delivery from April 1 , 1991 to December 31 , 1992 . Question naires were completed on sleeping position at 4 to 6 weeks of age and sets of st and ardized questions on development at 6 and 18 months . Main Outcome Measures . Social , communication , fine and gross motor , and total developmental scales based on the Denver Developmental Screening Test at 6 and 18 months . Results . After adjustment for 27 factors using multiple regression , 3 of the 10 scales and subscales significantly distinguished between front and back sleeping position . At 6 months of age , infants put to sleep on their front had a mean score 0.38 SD ( 95 % confidence interval [ CI ] : 0.28 , 0.49 ) higher on the gross motor scale , 0.11 SD ( 95 % CI : 0.00 , 0.23 ) higher in the social skills scale , and a total development score 0.20 SD ( 95 % CI : 0.10 , 0.30 ) higher than those on their backs . These differences were no longer apparent at 18 months . Conclusions . There is some evidence that putting infants to sleep in the supine position results in a reduced developmental score at 6 months of age , but this disadvantage appears to be transient . Weighing this against the adverse health effects demonstrated with the prone sleeping position , these results should not change the message of the Back to Sleep Campaign OBJECTIVE To compare duration of ventilation to mortality and adverse neurodevelopmental outcomes among extremely low birth weight ( ELBW ; 501 - 1000 g ) infants . STUDY DESIGN Retrospective analysis of prospect ively collected data from 5364 infants with a birthweight of 501 to 1000 g born at National Institute of Child Health and Human Development ( NICHD ) Neonatal Research Network centers from 1995 to 1998 . The main outcome measures were : survival , duration of mechanical ventilation , and neurodevelopmental outcome . RESULTS Overall survival was 71 % . The median duration of ventilation for survivors was 23 days ; 75 % were free of mechanical ventilation by 39 days , and 7 % were ventilated for > or = 60 days . Of those ventilated for > or = 60 days , 24 % survived without impairment . Of those ventilated for > or = 90 days , only 7 % survived without impairment . Of those ventilated > or = 120 days , all survivors were impaired . CONCLUSIONS The prognosis for ELBW with protracted ventilation remains grim . The cohort who remain intubated have diminished survival and high rates of impairment . Parents of these infants should be informed of changes in prognosis as the time of ventilation increases AIM The aim of this study was to determine the effectiveness of quarter turn from prone compared with supine and prone positioning in maintaining respiratory function in premature infants managed in a neonatal intensive care unit . METHODS The study was a prospect i ve , r and omised , cross-over trial with concealed allocation and intention to treat analysis . Fifty-four infants ≤32 weeks gestation were r and omly allocated to the order of the positions supine , prone and quarter turn from prone . Distribution of ventilation was assessed by measurement of regional impedance amplitude , global inhomogeneity index and phase angle analysis using electrical impedance tomography 30 min after each position change . Physiological characteristics of heart rate , respiratory rate ( RR ) , oxygen saturation and inspired oxygen were also measured . RESULTS There was a significant difference between positions for RR with the RR in quarter turn from prone significantly lower than for supine ( mean difference 6.53 breaths/min ; 2.04 - 11.02 ) , but not compared with the prone position . No significant differences between positions were found for any of the other outcomes measured . CONCLUSION This study demonstrated that quarter turn from prone had an immediate positive positional effect on the RR of premature infants . The position of quarter turn from prone was comparable with prone in the maintenance of lung function and had a superior effect over supine on RR . These findings support the view that a quarter turn from prone can be confidently used in neonatal nurseries to manage premature infants To determine the influence of body position on chest wall and pulmonary function , we studied the ventilatory , pulmonary mechanics , and thoracoabdominal motion profiles in 20 preterm infants recovering from respiratory disease who were positioned in both the supine and prone position . Thoracoabdominal motion was assessed from measurements of relative rib cage and abdominal movement and the calculated phase angle ( an index of thoracoabdominal synchrony ) of the rib and abdomen Lissajous figures . The ventilatory and pulmonary function profiles were assessed from simultaneous measurements of transpulmonary pressure , airflow , and tidal volume . The infants were studied in quiet sleep , and the order of positioning was r and omized across patients . The results demonstrated no significant difference in ventilatory and pulmonary function measurements as a function of position . In contrast , there was a significant reduction ( -49 % ) in the phase angle of the Lissajous figures and an increase ( + 66 % ) in rib cage motion in prone compared with the supine position . In addition , the degree of improvement in phase angle in the prone position was correlated to the severity of asynchrony in the supine position . We speculate that the improvement in thoracoabdominal synchrony in the prone position is related to alterations of chest wall mechanics and respiratory muscle tone mediated by a posturally related shift in the area of apposition of the diaphragm to the anterior inner rib cage wall and increase in passive tension of the muscles of the rib cage . This study suggests that the mechanical advantage associated with prone positioning may confer a useful alternative breathing pattern to the preterm infant in whom elevated respiratory work loads and respiratory musculoskeletal immaturity may predispose to respiratory failure Background : Changes in head posture influence brain hemodynamics . Optimal positioning has been recommended as 1 of 10 potentially better practice s to reduce the incidence of brain injury in preterm newborns . Objectives : The aim of this study was to evaluate by near-infrared spectroscopy ( NIRS ) the effect of different head and body positions and the influence of gestational age ( GA ) and nasal continuous positive airway pressure on brain hemodynamics in very preterm newborns . Methods : 24 stable preterm newborns were studied by NIRS in 6 different postures including head rotation and head inclination in both supine and prone positions . Changes in normalized tissue hemoglobin index 
    Output:
    
The subgroup ventilated with CPAP  ( three trials ; 59 participants ) showed a trend towards improving SpO2 in the prone position compared with the supine position , although the mean difference ( 1.91 % ) was not significant ( 95 % CI -1.14 to 4.97 ) and heterogeneity was extreme ( I2= 95%).Sensitivity analyses restricted to studies with low risk of selection bias showed homogeneous results and verified a small but significant effect ( MD 0.64 , 95 % CI 0.26 to 1.02 ; four trials ; 92 participants ; I2= 0).We also noted a slight improvement in the number of episodes of desaturation ; it was not possible to establish whether this effect continued once the intervention was stopped .
Evidence of low to moderate quality favours the prone position for slightly improved oxygenation in neonates undergoing mechanical ventilation .
However , we found no evidence to suggest that particular body positions during mechanical ventilation of the neonate are effective in producing sustained and clinical ly relevant improvement