***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: 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 Our objective was to determine the effect of posture on respiratory function and drive in prematurely born infants immediately prior to discharge . Twenty infants ( 6 oxygen-dependent ) , median gestational age 29 weeks ( range , 25 - 32 ) , were studied at a median postconceptional age ( PCA ) of 36 weeks ( range , 33 - 39 ) . On 2 successive days , infants were studied both supine and prone ; each posture was maintained for 3 hr . The order on each day in which postures were studied was r and omized between infants . At the end of each 3-hr period , tidal volume ( Vt ) , inspiratory ( Ti ) and expiratory ( Te ) time , respiratory rate , and minute ventilation were measured . In addition , respiratory drive was assessed by measuring the pressure generated in the first 100 msec of an imposed airway occlusion ( P(0.1 ) ) , and respiratory muscle strength was assessed by recording the maximum inspiratory pressure ( Pimax ) generated against an occlusion which was maintained for at least five breaths . Overall , tidal volume was higher ( P < 0.05 ) , but respiratory rate ( P < 0.05 ) , P(0.1 ) ( P < 0.05 ) , and Pimax ( P < 0.05 ) were lower in the prone compared to the supine position . There were no significant differences in Ti or Te between the two postures . In oxygen-dependent infants only , minute volume was higher in the prone position ( P < 0.05 ) . In conclusion , posture-related differences in respiratory function are present in prematurely born infants studied prior to neonatal unit discharge Studies of the effect of body position during and after bolus feeding upon gastric emptying or gastric residual have not had consistent results . We tested the hypotheses that right lateral decubitus leads to less gastric residual than left lateral decubitus and that the prone position leads to less gastric residual than the supine position . A prospect i ve r and omized clinical trial with triple crossover of healthy growing , appropriate for gestational age preterm infants . Each infant was successively studied while fed in the four different positions .  Gastric residuals were measured at 1 and 3 hours after initiation of feeding and returned . Thirty-one patients were studied . At 1 hour , right lateral decubitus led to less significant residuals than the left lateral decubitus and the prone position led to less residual than the left lateral decubitus . The amount of gastric residuals 1 hour after a meal appears to be in the following decreasing order : left , supine , prone , right UNLABELLED BACKGROUND . The preterm infant is subject to the force of gravity : when its body lies pressed against the mattress on which it is placed . AIMS The purpose of this study was to investigate short-term effects of varied post-natal lying positions in order to prevent neuromuscular and postural abnormalities . METHODS 60 low risk preterm infants of 31 - 36 weeks gestational age were enrolled for this r and omised clinical trial . Initially each child underwent neurological and psychomotor assessment s which included tonus and reflex protocol s as well as behavioral , sensory motor and postural examinations . The lying positions of the treated group were varied ( back , prone , and side ) using a specially design ed moldable mattress that maintained the functional position of the infant 's body . The control group was placed on their stomachs , ( the st and ard lying position used in 1994 ) with a st and ard orthopaedic bolster support under their hips . All infants underwent a second round of examinations upon discharge to assess any changes in neurological and psychomotor outcomes . RESULTS The sensory-motor skills examinations showed significant abnormalities in the control group : ( 1 ) dominance of the extensor muscles due to muscle shortening , ( 2 ) hyper abduction and flexion of the arms , and ( 3 ) global neuromuscular rigidity . Psychomotor and neurological exams of the control and treatment groups showed delayed developmental muscular acquisitions for infants in the control group . CONCLUSION Regular changes in posture , while retaining correct functional positions , allowed maintenance of normal neuromuscular and osteo-articular function and permitted the development of spontaneous and functional motor activity in low-risk perterm infants OBJECTIVE : The purpose of this study was to determine the effects of prone and supine positioning on the cardiorespiratory stability of preterm infants with apnea and bradycardia . METHODS : A total of 22 preterm infants with symptomatic apnea and bradycardia ( gestational age of 26.9 ± 1.8 weeks and birth weight of 865 ± 235 gm ) were monitored for 24 hours ( in four sequential 6-hour blocks ) for apnea , bradycardia , and oxygen desaturation in alternating positions ( prone or supine ) following r and omization . Postconceptional age at the time of study was 31.9 ± 3.0 weeks . Respiratory rate , heart rate , and transcutaneous oxygen saturation were continuously monitored . All episodes of apnea ( ≥10 seconds ) , bradycardia ( < 100 beats per minute ) , and oxygen desaturation ( < 90 % ) were recorded on an event monitor . Episodes of apnea , bradycardia , and oxygen desaturation were defined as clinical ly significant if the following criteria were met : apnea , ≥15 seconds ; bradycardia , < 90 beats per minute ; and oxygen desaturation , < 80 % . All other recorded episodes were considered mild . The episodes were analyzed for statistical significance using the paired t-test . RESULTS : No significant differences ( p > 0.05 ) in the incidence of clinical ly significant apnea , bradycardia , or desaturation between supine and prone positions were seen in these preterm infants . CONCLUSION : Our results suggest that the cardiorespiratory stability of preterm infants is not significantly compromised by supine positioning Objective The purpose of this study was to examine the influence of prone and supine position in preterm infants during acute pain of blood collection . Setting Level III Neonatal Intensive Care Unit ( NICU ) . Study Design Thirty-eight preterm infants ( birthweight 1339 [ 590–2525 ] g , GA 29 [ 25– 32 ] wks ) were in 2 groups depending on their position in the isolette prior to and during heel lance at 32 weeks post-conceptional age . The study design was a comparison between groups ( Prone , Supine ) during 2 events ( Baseline , Heel lance ) . Outcome MeasurePain measures were multidimensional , including behavioral ( sleep – wake state and facial activity ) and physiological ( heart rate ) responses measured continuously prior to ( Baseline ) and during blood collection ( Lance ) . Results Both groups of infants displayed statistically significant shifts in sleep – wake state to greater arousal , and increased facial activity and heart rate , from Baseline to Lance . Prone position was associated with significantly more deep sleep during Baseline , compared with Supine position , but there were no differences in sleep-wake state during Lance . Minor increased facial activity was shown in some time segments of Baseline for infants in Supine compared with Prone , but did not differ overall between positions . Prone and Supine position did not affect heart rate significantly during Baseline or Lance events . Conclusions Prone position promotes deep sleep in preterm neonates at 32 weeks post-conceptional age when they are undisturbed . However , placement in prone position is not a sufficient environmental comfort intervention for painful invasive procedures such as heel lance for blood sampling in the NICU . Neonates require other environmental supports to promote coping with this stressful event Background . As a result of the American Academy of Pediatrics ' recommendation that healthy infants be placed on their side or back for sleep , the percentage of infants sleeping prone has decreased dramatically . With the increase in supine sleeping , pediatricians have question ed if there are differences in the rate of acquisition of early motor milestones between prone and supine sleeping infants . Methods . To examine this question , we performed a prospect i ve , practice -based study of healthy term infants . Infants were recruited before the age of 2 months . Parents were asked to record infant sleep position and awake time spent prone until 6 months of age . A developmental log was used to track milestones from birth until the infant was walking . Age of acquisition of eight motor milestones was determined , and the mean ages of milestone attainment of prone and supine sleepers were compared . Results . Three hundred fifty-one infants completed the study .  Prone sleepers acquired motor milestones at an earlier age than supine sleepers . There was a significant difference in the age of attainment of rolling prone to supine , tripod sitting , creeping , crawling , and pulling to st and . There was no significant difference in age when infants walked . Conclusions . The pattern of early motor development is affected by sleep position . Prone sleepers attain several motor milestones earlier than supine sleepers . However , all infants achieved all milestones within the accepted normal age range . Pediatricians can use this information to reassure parents . This difference in milestone attainment is not a reason to ab and on the American Academy of Pediatrics ' sleep position recommendations OBJECTIVE We investigated whether nursing in the head elevated tilt position ( HETP ) , compared with the horizontal position , has any effect on the incidence of bradycardic and hypoxemic episodes in preterm infants . METHODS Twelve spontaneously breathing preterm infants with idiopathic recurrent apnea were studied in a r and omized controlled crossover trial . Nine infants were treated with aminophylline . Each spent a total of 24 hours in the horizontal prone position and a total of 24 hours in HETP ( prone , 15 degrees ) . The position was changed in r and om order every 6 hours . Thoracic impedance , heart rate , and arterial oxygen saturation were recorded continuously . The frequency of isolated hypoxemia ( arterial saturation < 80 % ) , of isolated bradycardia ( heart rate < 90 beats per minute ) , and of mixed events was analyzed and compared without knowledge of the allocated position . RESULTS In total , there were significantly fewer bradycardic and /or hypoxemic episodes ( 28.2 % ) in HETP compared with the horizontal position ( mean difference , 13.35 episodes/24 hours ; 95 % confidence interval [ CI ] : 5.9- 20.8 ) . The decrease was largest for isolated hypoxemic episodes ( 48.5 % ; mean difference , 11.74 episodes/24 hours ; 95 % CI : 6.1 - 17.4 ) . Isolated bradycardic episodes ( mean difference , 2.27 episodes/24 hours ; 95 % CI : -0.78 - 5.31 ) and mixed events were not decreased significantly in HETP . CONCLUSIONS Nursing in a moderately tilted position ( 15 degrees ) reduces hypoxemic events in preterm infants . This intervention is easy to apply , quickly reversible , and can be combined with drugs such as aminophylline OBJECTIVE . Prematurely born compared with term born infants are at increased risk of sudden infant death syndrome , particularly if slept prone . The purpose of this work was to test the hypothesis that preterm infants with or without bronchopulmonary dysplasia being prepared for neonatal unit discharge would sleep longer and have less arousals and more central apneas in the prone position . METHODS . This was a prospect i ve observational study in a tertiary NICU . Twenty-four infants ( 14 with bronchopulmonary dysplasia ) with a median gestational age of 27 weeks were studied at a median postconceptional age of 37 weeks .  Video polysomnographic recordings of 2-channel electroencephalogram , 2-channel electro-oculogram , nasal airflow , chest and abdominal wall movements , limb movements , electrocardiogram , and oxygen saturation  were made in the supine and prone positions , each position maintained for 3 hours . The duration of sleep , sleep efficiency ( total sleep time/total recording time ) , and number and type of apneas , arousals , and awakenings were recorded . RESULTS . Overall , in the prone position , infants slept longer , had greater sleep efficiency ( 89.5 % vs 72.5 % ) , and had more central apneas ( median : 5.6 vs 2.2 ) , but fewer obstructive apneas ( 0.5 vs 0.9 ) . The infants had more awakenings ( 9.7 vs 3.5 ) and arousals per hour ( 13.6 vs 9.0 ) when supine . There were similar findings in the 
    Output:
    
The results of this review support the prone position in preterm infants for improvement of arterial oxygen saturation , improved lung and chest wall synchrony of respiratory improvements , decreased incidence of apnea in infants with a clinical history of apnea , promoted sleep , and decreased gastroesophageal reflux .
However , the prone position increased postural abnormalities , orthopaedic abnormalities of the feet , and delayed developmental musculature .
The combined use of a postural support roll and a postural nappy while very preterm infants are nursed , improved hip and shoulder posture up to term postmenstrual age .
The change in body position from horizontal to head-up tilt in very immature and unstable infants may affect the cerebral homodynamic .
The management of position per se may not be sufficient for assisting preterm neonates to cope with the painful procedure .
Furthermore , preterm infants are susceptible to oxygen desaturation in car seats and carrying slings .
Prone positioning was shown to have many advantages for prematurely born infants .
But the longer , deep sleep period and fewer awakenings associated with a prone position would support higher vulnerability for preterm infants to sudden infant death syndrome ( SIDS ) .