***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: Aminophylline and caffeine are commonly used for prophylaxis of apnea in premature infants . Previous studies have indicated different effects of the drugs on cerebral circulation . Therefore , we have compared the acute effects of bolus administration of caffeine citrate or aminophylline on left ventricular output , heart rate , blood pressure and global cerebral blood flow . The study group consisted of 33 newborn , spontaneously breathing , preterm infants r and omly assigned to receive either aminophylline 5mg/kg  ( n= 19 )  or caffeine citrate 20mg/kg  ( n= 14 ) . Two hours after iv drug administration , global cerebral blood flow measured by the Xe‐clearance technique was significantly lower after aminophylline than after caffeine ( mean(SD ) ) : 13.2 ( + 2.9/ ‐ 2.3 ) versus 17.2 ( + 7.1/ ‐ 5.1 ) ml/100 g/min ) ( p= 0.01 ) . There were no other statistically significant differences in circulatory or ventilatory parameters between the groups . Further studies are needed to clarify the clinical relevance of these results To determine if the use of oxygen in the delivery room influences subsequent global cerebral blood flow ( CBF ) , 70 infants of gestational age of less than 33 completed weeks were r and omly assigned to receive room air ( group I ) or 80 % oxygen ( group II ) during the initial stabilisation at birth . In group I supplemental oxygen was administered on clinical indications , when required . After being admitted to the neonatal intensive care unit all infants were treated according to our normal practice . At a postnatal age of 2 hours CBF was measured by xenon clearance . Seventy four per cent of the infants in group I were successfully stabilised without the need for supplemental oxygen . CBF was significantly higher in group I than in group II ( CBF median ( interquartile range ) : 15.9 ( 13.6 - 21.9 ) v 12.2 ( 10.7 - 13.8 ) ml/100 g/minute ) . Differences in oxygen exposure seemed to be the only explanation for the differences in CBF . No differences in short term outcome were found between the groups OBJECTIVE To investigate the effects on oxygenation of targeting the higher versus the lower end of the currently recommended range for pulse oximetry ( Spo2 ) . DESIGN Nonr and omized crossover trial with the use of within-subject comparisons ( two-tailed paired t test ) . SETTING Level III neonatal intensive care unit of a university hospital . PATIENTS Twenty infants whose lungs were mechanically ventilated ( mean + /- SD : birth weight , 1192 + /- 396 gm ; gestational age , 28.7 + /- 2.7 weeks ; age at time of study , 42 + /- 26 hours ) . INTERVENTIONS The inspired oxygen concentration was adjusted to achieve Spo2 readings of 93 % to 96 % versus 89 % to 92 % ( Ohmeda pulse oximeter ) or 95 % to 98 % versus 91 % to 94 % ( Nellcor oximeter ) . MEASUREMENTS Cardiac output was measured by echocardiography , oxygen content of arterial blood sample s by cooximetry , and oxygen consumption by indirect calorimetry . RESULTS The inspired oxygen concentrations required to achieve the Spo2 target ranges were 39.8 % + /- 8.3 % versus 28.7 % + /- 6.1 % ( p < 0.001 ) . The respective arterial oxygen contents were 18.0 + /- 2.6 ml/dl versus 16.9 + /- 2.5 ml/dl ( p < 0.001 ) . Oxygen consumption was unchanged . In the lower-oxygen condition no compensatory increase in cardiac output was detected ; thus the estimated mixed venous oxygen tension decreased and the oxygen extraction ratio increased . Venous admixture increased from 15 % + /- 6 % to 31 % + /- 9 % in the lower-oxygen condition ( p < 0.001 ) . CONCLUSIONS The " low normal " Spo2 target range allowed for less oxygen exposure . No signs of mismatch between systemic oxygen delivery and dem and could be detected Sleep fragmentation , decreased rapid eye movement ( REM ) sleep time , and REM sleep hypoxemia have been reported in infants with chronic neonatal lung disease ( CNLD ) in early infancy despite an awake hemoglobin oxygen saturation ( SaO2 ) > 93 % . Interestingly , higher inspired O2 concentrations have been demonstrated to reduce REM sleep fragmentation in CNLD patients in middle infancy . However , the effect of increased SaO2 on sleep architecture in infants with CNLD near the time of discharge from neonatal intensive care has not been reported . We performed paired overnight polysomnography in a sleep laboratory on 16 infants with CNLD ( 4 weeks median corrected age ) in air or their usual inspired oxygen ( SaO2 > 93 % ) and again when receiving 0.25 L/min higher than baseline inspired oxygen via nasal catheters ( SaO2 > 97 % ) . A control group of seven healthy preterm infants was similarly studied . For CNLD infants on supplemented O2 , sleep duration decreased by 15 % ( 422+/-66 min vs. 359+/-89 min ; P < 0.005 ) , and sleep efficiency decreased by 7 % ( 73.2+/-10.6 % vs. 66.4+/-14.0 % ; P < 0.005 ) but percentage of time in REM sleep ( REM% ) ( 31.5+/-8.9 % vs. 29.8+/-8.6 % ; P=0.560 ) , REM epoch duration ( 12.4+/-2.8 min vs. 13.4+/-4.3 min ; P=0.420 ) , and REM arousal index ( 18.6+/-6.5 vs. 18.8+/-7.2 ; P=0.990 ) were not significantly affected . Conversely , higher O2 did not alter sleep architecture in the control group . The mean non-REM ( NREM ) respiratory rate decreased ( CNLD : P=0.003 ; controls : P=0.02 ) , NREM SaO2 increased ( P < 0.05 ) , although the mean transcutaneous CO2 was unaltered in both CNLD and control groups . This study confirmed low REM% in CNLD infants in early infancy and demonstrated that a higher SaO2 adversely affected sleep time but did not influence REM sleep duration or arousal frequency . A target SaO2 > 93 % is , therefore , as efficacious as an SaO2 > 97 % in optimizing sleep architecture in CNLD infants A previous report has shown no difference between the clinical outcome of infants exposed to a high oxygen ( O2 ) regimen and those exposed to a low O2 regimen for the treatment of respiratory distress syndrome ( RDS ) .  Mechanical ventilation was not used in either group . In the present study , pulmonary function tests were performed on 14 survivors receiving the low O2 regimen ( low O2 group ) and on nine receiving the high O2 regimen ( high O2 group ) ten years after their initial illness . Similar evidence of abnormalities of large airways was found in both groups of prematurely born children that was comparable with that previously reported for normal prematurely born children . There was evidence in the high O2 group similar to that reported for ventilated survivors with RDS exposed to a high concentration of O2 . From these data , it was concluded that neonatal exposure to high O2 concentrations in the absence of mechanical ventilation is capable of causing long-term change in small airways This study was performed to determine whether the use of continuous transcutaneous oxygen tension ( tcPO2 ) monitoring could reduce the incidence of retinopathy of prematurity in preterm infants receiving oxygen therapy . A total of 296 infants with birth weights less than or equal to 1,300 g were r and omly assigned to a continuous monitoring or a st and ard care group . Infants in the continuous monitoring group had  tcPO2  monitored continuously as long as they required supplemental oxygen , and infants in the st and ard care group had  tcPO2  monitored only during the more acute state of their illness . Management of both groups was otherwise identical . Of 148 infants in the continuous monitoring group , 101 survived ; of the 148 patients in the st and ard  care group , 113 survived . Mean birth weights and gestational ages were similar for both groups . Duration of mechanical ventilation and oxygen therapy was also similar . The overall incidence of retinopathy of prematurity was 51 % in the continuous monitoring group and 59 % in the st and ard care group . As birth weight for infants greater than or equal to 1,000 g increased , a higher risk of retinopathy of prematurity developing was noted in the st and ard care group . Cicatricial retinopathy of prematurity developed in four infants in the continuous monitoring group and five in the st and ard care group . These results suggest that continuous tcPO2 monitoring may reduce the incidence of retinopathy of prematurity in infants with birth weights greater than 1,000 g but not in the smaller infants in whom this complication occurs more frequently and is more severe Between 1966 and 1970 , infants with birthweights between 1000 and 1500 g entered a r and omized controlled trial to determine the short‐term and long‐term results of neonatal intensive care . Of 158 long‐term survivors , five were lost to follow‐up , but the multidisciplinary research team prospect ively followed 143 children up to the age of eight years . Useful data were available for the other 10 children . Of the long‐term survivors 74 had received routine , and 84 had received intensive nursery care Oxygen saturation determined by pulse oximetry was monitored in 152 pediatric surgical patients divided into two groups . In one group , the oximeter data and alarms were available ( N = 76 ) to the anesthesia team , and , in the other group , these data were unavailable ( N = 76 ) . A trained observer recorded all intraoperative hypoxic episodes and informed the anesthesia team of all major events ( i.e. , oxygen saturation less than or equal to 85 % for greater than or equal to 30 s ) ( PaO2 approximately 52 mmHg ) . Thirty-five major events occurred : 24 in the unavailable group , and 11 in the available group ( P = 0.021 ) . A greater number of major events occurred in children less than or equal to 2 yr of age ( P = 0.013 ) . Hypoxic events diagnosed by the oximeter , but not by the anesthesiologist , were more frequent in the unavailable group ( 13 ) than in the available group ( 5 ) ( P = 0.0495 ) . ASA Physical Status 3 and 4 patients were more likely to suffer a major event ( P = 0.009 available , 0.006 unavailable ) . The pulse oximeter diagnosed hypoxemia before the signs and symptoms of hypoxemia were apparent ( i.e. , prior to observed cyanosis or bradycardia ) . Major hypoxic events were unrelated to duration of anesthesia . Major events were evenly distributed among induction , maintenance , and awakening from anesthesia ; a greater number of hypoxic events occurred during induction in the unavailable group ( P = 0.031 ) . No morbidity was documented in any patient who suffered an hypoxic event . ( ABSTRACT TRUNCATED AT 250 WORDS The relation between PaO2 and retrolental fibroplasia ( RLF ) was studied prospect ively in 719 premature infants born in or treated in the intensive care units of a group of university hospitals .  Blood gas studies  were performed on 589 of these infants , 66 of whom had a diagnosis of RLF ; in 27 of these 66 , some grade of mostly nonblinding cicatricial disease developed . The frequency of RLF was highest among infants of lowest birth weight . A multivariate statistical method was used to analyze simultaneously the effect of possible etiologic factors associated with RLF . The occurrence of RLF was found to be unrelated to PaO2 , as determined by the limited information available from intermittent sampling . RLF is associated with concentration of oxygen administered in the lightest birth weight group , but the strongest association , aside from birth weight , was with time in oxygen . None of the other variables involving blood chemical values appeared to be associated with RLF . The severity of cicatricial RLF is clearly greater in infants weighing less than 1,200 g at birth . Conservative administration of oxygen may have been responsible for failure to demonstrate quantitative association between PaO2 levels and disease . Agreement between the observed and predicted numbers of infants with RLF demonstrate the strength of the multivariate technique employed in making the statistical analyses AIMS : To determine if decreasing arterial blood saturation from 95 % to 90 % could cause vasoconstriction of the pulmonary vasculature and dilatation of a patent ductus arteriosus in preterm newborn infants with respiratory distress syndrome ( RDS ) . METHODS : Doppler echocardiographic studies were compared at 95 % and 90 % pulse oxygen saturation ( SpO2 ) in 13 preterm infants aged 61.7 ( 4.3 ) hours with RDS and Doppler echocardiographic evidence of tricuspid regurgitation . RESULTS : The mean (SD)Doppler echocardiographic indices 
    Output:
    
The one trial that specifically addressed the question of lower versus higher PaO2 found no effect on death , but did not report ( in sufficient detail to warrant inclusion ) the effect of this intervention on eye or other outcomes .
REVIEW ER 'S CONCLUSIONS The results of this meta- analysis confirm the commonly held view of today 's clinicians that a policy of unrestricted , unmonitored oxygen therapy has potential harms , without clear benefits .