High-frequency oscillatory ventilation combined with intermittent mandatory ventilation in critically ill neonates: 3 years of experience

A heterogeneous group of 45 neonates with severe pulmonary disease and inadequate gas exchange on conventional intermittent mandatory ventilation (IMV) was treated with a high-frequency oscillator combined with an IMV (HFO-IMV) system (Emerson Airway Vibrator connected to a BABYBird 1 ventilator). The mean gestational age was 33 weeks (25.5–43) and mean birth weight 2.02 kg (0.66–4.24). Primary diagnoses included respiratory distress syndrome (RDS; 23), pneumonia (12), persistent fetal circulation (PFC; 6), diaphragmatic hernia/hypoplastic lungs (4). The IMV rate was reduced from 78 to 29 BPM (P0.0005), while maintaining lower partial pressure of carbon dioxide (PaCO₂) (P<0.005) and higher partial pressure of oxygen (PaO₂) (P0.0025). Active air leaks were present in 20 infants and these infants responded most favourably to HFO-IMV. HFO-IMV failed to improve ventilation in neonates with diaphragmatic hernia/hypoplastic lungs. Complications during HFO-IMV were increased pulmonary secretions (11), worsening or recurrence of pre-existing air leaks (11), or occurrence of new air leaks (10). In 4 patients death was related to major air leak complications. Twenty-four infants died, 18 of them of a respiratory cause. Twenty-one infants finally survived. We assembled a well-tolerated system to provide HFO-IMV and to successfully ventilate neonates with severe respiratory disease, who failed to respond to conventional IMV. Initiation of HFO-IMV earlier in the course of the disease in this type of infant may improve survival.Abbreviations BPM breaths per minute - FiO₂ fraction of inspired oxygen - HFI high-frequency flow interrupter - HFJ(V) high-frequency jet (ventilation) - HFO high-frequency oscillation - HFO-IMV high-frequency oscillation combined with intermittent mandatory ventilation - HFPP(V) high-frequency positive pressure (ventilation) - IMV intermittent mandatory ventilation - P(a)CO₂ partial pressure of (arterial) carbon dioxide - P(a)O₂ partial pressure of (arterial) oxygen - Paw mean airway pressure - PFC persistent fetal circulation - PIE pulmonary interstitial emphysema - PIP peak inspiratory pressure - RDS (infant) respiratory distress syndrome     

Exercise Performance After Surgery for Pulmonary Atresia and Intact Ventricular Septum

The objective of this study was to assess exercise performance in subjects born in Sweden between 1980 and 1995 and undergoing surgery for pulmonary atresia and intact ventricular septum and to identify determinants of exercise performance. Twenty-seven subjects, 16 with biventricular repair and 11 with univentricular palliation, and 28 age- and sex-matched controls completed cardiopulmonary exercise and lung function testing. Peak oxygen uptake was determined using a symptom-limited ramp bicycle exercise protocol. Regression analysis was performed to identify predictors of peak oxygen uptake (V′O₂), The index group had lower peak V′O₂ (1.4 [median 0.8; range 2.5] l/min) than controls (1.9 [0.7; 3.1]; p < 0.05). Subjects without ventriculocoronary arterial communications (VCAC), corrected to biventricular circulation, had higher peak V′O₂, than the remaining index subjects. Decreased total lung capacity, low minute ventilation, and high physiologic dead space measured at peak exercise were all independent determinants of low peak V′O₂ Exercise capacity is generally decreased in subjects with pulmonary atresia and intact ventricular septum, although there are marked interindividual differences. Good exercise capacity was found in subjects without VCAC who had undergone biventricular repair. Decreased lung function was an unfavourable predictor of exercise capacity.     

Prediction of individual response to postnatal dexamethasone in ventilator dependent preterm infants

AIMS—To evaluate factors predictive of individual response to dexamethasone in preterm infants.
METHODS—A cohort of 74 preterm infants born between January 1993 and February 1996 was studied retrospectively. All of them had received dexamethasone to facilitate weaning from artificial ventilation. Demographic factors, ventilation parameters, and details of dexamethasone administration were recorded from the medical and nursing notes. Radiographs were assessed by one observer who was unaware of the clinical condition of the infant or the outcome. Outcome variables examined included change in ventilation index (VI) at 36-48 hours, the number of days to extubation from the start of dexamethasone, and death before extubation.
RESULTS—Most babies improved but changes in VI at 36-48 hours ranged from substantial deterioration to dramatic improvement. No identifiable factors were significantly associated with this range of response. The median time to extubation was 6 days. The 36 babies who extubated within the first 6 days were: significantly more mature; less likely to have pulmonary interstitial emphysema (PIE) or pneumothorax; and had significantly lower VIs in the 12 hours preceding dexamethasone treatment. The postconceptional age at extubation was the same whether babies were extubated within or after the first 6 days. Multiple linear regression confirmed a significant association between number of days to extubation and the three factors described above (adjusted R²=0.5126).
CONCLUSIONS—Individual responses to dexamethasone can be partly predicted by gestation, the presence of PIE, and the VI before dexamethasone administration.

     

The effect of positive endexpiratory pressure, peak inspiratory pressure, and inspiratory time on functional residual capacity in mechanically ventilated preterm infants

In mechanical ventilation of preterm infants, positive endexpiratory pressure (PEEP) is widely used to prevent alveolar collapse, maintain functional residual capacity (FRC) and improve oxygenation. Prolongation of inspiratory time (t_i) and increase of peak inspiratory pressure (PIP) are also used for this purpose. We investigated the effect of variations of PEEP, PIP and t_i on FRC in ten infants with hyaline membrane disease and onset of bronchopulmonary dysplasia (BPD, n= 7), pulmonary hypertension (n= 1), pulmonary hypoplasia (n= 1) or severe BPD (n= 1) (gestational age 24–39 weeks, median 26 weeks; birth weight 590–2960 g, 785 g; chronological age 7–84 days, 19 days; weight 689–4650 g, 1185 g). FRC, measured using the sulphur hexafluoride washout technique, was between 6.2 and 48.3 ml/kg (median 21.5 ml/kg). PEEP was changed stepwise 2–5 times in each patient (median 3) and mean airway pressure (MAP) was modified independently of PEEP by changing PIP 0–2 times (median 1) and t_i 0–2 times (median 2). Changes of FRC correlated well with modifications of PEEP in each patient (r= 0.90, range 0.71–0.99). The slope factors of linear correlations had a median value of 2.94 ml/cm H₂O per kg, which was significantly different from zero (P < 0.01) and significantly higher than the slope factors of linear correlations between FRC and MAP after modifications of PIP or t_i (P < 0.01). The latter two were statistically not different from zero. The quotients ΔFRC/ΔMAP were significantly higher after adjustments of PEEP than after adjustments of PIP or t_i (P < 0.01). The time lag between the change of PEEP and the stabilization of FRC on a new level ranged from 2 to 14 min (median 5). Conclusion FRC is mainly determined by PEEP but not by PIP or t_i. Stabilization of FRC after a change of PEEP can last up to 14 min. Its duration is unpredictable and has to be waited for when testing pulmonary function in ventilated preterm infants. Received: 18 November 1997 / Accepted: 7 January 1998     

Treatment of severe meconium aspiration syndrome with porcine surfactant

Abstract This study is based on clinical data from a retrospective series of 54 infants with meconium aspiration syndrome treated with porcine surfactant at a median age of 14 h (range 1–176 h). Median arterial/alveolar oxygen tension ratio (a/APO₂ ratio) before treatment was 0.08 (range 0.02–0.23) and oxygenation index 25 (range 6–110). After treatment with surfactant at an initial dose of 50–200 mg/kg there was a modest but statistically significant increase in a/APO₂ ratio associated with a reduction of oxygenation index. Ten (18%) babies showed a 3–4 fold increase in a/APO₂ ratio within 1–2 h of treatment. Twenty-four (44%) babies showed little or no response by 1–2 h with the remaining infants showing modest improvement in oxygenation. One third of babies required repeated doses of surfactant. Twenty-eight day survival was 81%, with two babies requiring extracorporeal membrane oxygenation. Conclusion Natural surfactant treatment of severe meconium aspiration may prove to be a useful intervention and randomised controlled clinical trials should be undertaken.     

Persistent pulmonary abnormalities in newborns: The changing picture of bronchopulmonary dysplasia

Significant changes in the radiographic features of bronchopulmonary dysplasia (BPD) have accompanied recent advances in treatment of neonatal respiratory distress syndrome. Retrospective study of 709 newborns showed atypical radiographic findings in many patients with clinical BPD. While 12/20 infants with clinical BPD showed changes identical to Northway's stage 4 disease, the remaining 8 (40% of patients with significant respiratory dysfunction) had diffuse, fine infiltrates without emphysema. Radiographic progression from RDS through all Northway stages was observed in only 4 patients. Diagnosis of stage 2 BPD was complicated by the presence of PDA in 9/17 cases. Stage 3 BPD was identified with certainty in only 5 infants, but may have coexisted with PIE in as many as 22 cases. Nevertheless, there was close agreement between the radiographic findings and clinical severity of chronic lung disease. Mild (type 1) infiltrates following RDS may be distinguished from chronic pulmonary insufficiency of prematurity (CPIP) or “immature lung”. In patients who require only short-term supplemental O₂, type 1 changes may reflect delayed resolution of RDS in an underdeveloped lung. These same findings in infants with prolonged O₂ dependence usually indicate a mild form of BPD. Coarse infiltrates and emphysema (type 2) are almost always associated with severe respiratory impairment.     

Determinants of oxygenation during high frequency oscillation

Two studies are reported in which the aim was to assesses whether oxygenation on transfer to or during high frequency oscillation (HFO) was influenced by the mean airway pressure (MAP) level. Sixteen infants, median gestational age 28 weeks, were recruited into the first study and 14 with a median gestational age of 29 weeks into the second. In the initial study, blood gases were measured immediately before and 30 min after transfer to HFO and comparison made of those infants in whom oxygenation did or did not improve. In the second study the infants were studied at two MAP levels, 2 and 5 cmH₂O, above that used during conventional ventilation (baseline MAP) and at two frequencies (10 and 15 Hz), arterial blood gases were measured after 20 min on each setting. In the initial study, on transfer to HFO, oxygenation improved by a median of 21 mmHg in eight infants, but was either unchanged or deteriorated (n=7) in the other eight infants, the median impairment in oxygenation was by 17 mm Hg. The infants in whom oxygenation improved had required a significantly higher MAP during conventional ventilation than the rest of the study group. In the second study, increasing the MAP from 2 to 5 cmH₂O above baseline resulted in a significant increase in oxygenation, which was significantly greater at 10 rather than 15 Hz. Infants whose MAP remained below 13 cmH₂O had impaired oxygenation during HFO compared to that experienced during conventional ventilation. The results of these two studies demonstrate that the MAP level during HFO is an important determinant of oxygenation.     

Risk factors for fatal pulmonary interstitial emphysema in neonates

Among 315 infants treated for respiratory distress syndrome (RDS) over a 2 year period, 32 prematures were studied retrospectively with the diagnosis of pulmonary interstitial emphysema (PIE). Eighteen died. In this group, birth weight below 1600 g, need for oxygen above 0.6 on the 1st day and appearance of bilateral pulmonary interstitial emphysema within the first 48h of life were significant risk factors, with a mortality rate of 94%. In order to recognize one or more early criteria predictive of fatal PIE, we compared ventilation parameters on day 1 between neonates with fatal PIE and those with the same birth weight and initial severity of RDS but without PIE treated during the same period. High positive inspiratory pressure on day 1 was found to be the most significant parameter associated with further appearance of fatal pulmonary interstitial emphysema. A cut-off level of 26 cm H₂O was found to be discriminant. These criteria may be useful in selecting those neonates who might best benefit from a new therapy such as high frequency ventilation, before irreversible lesions appear.     

Pulmonary interstitial emphysema due to respiratory syncytial virus infection

Pulmonary interstitial emphysema (PIE) primarily affects premature infants on positive pressure ventilation. PIE is rarely reported in infants and children in the absence of mechanical ventilation and/or associated respiratory infection. We report a case of PIE in a 22‐month‐old girl who had severe respiratory distress due to respiratory syncytial virus infection. Chest computed tomography showed cystic lung lesions mimicking congenital cystic adenomatoid malformation. The cystic lesions spontaneously resolved after conservative treatment. Based on the clinical course and the chronological changes on imaging, the cystic lung lesions were diagnosed as localized persistent PIE.     

Outcome of ventilated infants born at term without major congenital abnormalities

The longer-term outcome of term-born infants without congenital anomalies requiring ventilation in the first 24 h after birth has rarely been reported. Our aims were to determine the mortality and long-term morbidity of such infants and identify risk factors for adverse outcome. The outcomes of 43 of 45 infants born at term consecutively requiring mechanical ventilation were reviewed. The infants had: meconium aspiration syndrome (n = 11), hypoxic ischaemic encephalopathy (HIE) (n = 11), respiratory depression (n = 12), sepsis (n = 5), persistent pulmonary hypertension of the newborn (n = 3) and middle cerebral artery infarction (n = 1). Eleven infants developed seizures (26%), 13 (30%) had abnormal electroencephalograms and 11 (26%) had abnormal MRI scans; 26% had an adverse outcome: six died, and five had severe neurodisability at 2 years. The infants with congenital toxoplasmosis and a middle cerebral artery infarction were excluded from the prediction analysis. In the remaining 41 patients, requirement for anticonvulsants (relative risk, RR = 4.44, 95% CI = 1.48 to 12.70; p = 0.014) and prolonged ventilation (longer than 3 days) (RR 4.83, 95% CI 1.51 to 15.64) predicted adverse outcome. Infants with HIE had an increased risk of adverse outcome (relative risk 5.45, 95% CI 1.01 to 33.85), but an adverse outcome occurred in infants with other diagnoses. Conclusion: Mortality and neurodisability at follow-up were common in infants born at term without major congenital anomalies who required mechanical ventilation in the first 24 h after birth, particularly in those who developed seizures requiring treatment and prolonged ventilation.     

High frequency oscillatory ventilation in infants with increased intra-abdominal pressure

AIMS—To describe the short term effect of high frequency oscillatory ventilation on infants with severe abdominal distension who could not be conventionally ventilated.METHODS—Eight infants (25 to 38 gestational weeks, birthweight 600-3200 g, postnatal age 1 to 190 days) with a variety of intra-abdominal pathologies, resulting in severe abdominal distension and failure of conventional ventilation, were studied.RESULTS—The oxygenation status of all infants significantly improved within an hour of changing from conventional to high frequency oscillatory ventilation. Infants who were hypercapneic on conventional ventilation also showed a reduction in PaCO₂. As a group, the mean (SD) PaO₂/FIO₂ improved from 4.99 (0.98) kpa to 11.55 (3.8) kpa (P = 0.002), and the PaCO₂ from 6.48 (2.12) kpa to 4.89 (1.22) kpa (P= 0.028). These improvements were sustained throughout the next 48 hours.CONCLUSION—High frequency oscillatory ventilation seems to be an effective rescue measure for infants with respiratory failure secondary to increased intra-abdominal pressure.     

Delayed chemoreceptor responses in infants with apnoea

Aims: To test the hypothesis that apnoea of infancy (AOI) is due to a deficit in chemoreception. Methods: Tests were performed on 112 infants: 43 healthy control infants, 28 infants with periodic breathing or central apnoea (PBCA), and 41 infants with obstructive apnoea (OA) on overnight polysomnography. Chemoreceptor responses to hypercapnia (4% and 6% CO₂ in air) for 6–8 minutes and hyperoxia (100% O₂) for 60 seconds were expressed in terms of response strength and reaction time. Age at birth (gestational week 37–41) and age at test (2–34 postnatal weeks) were comparable across groups (median, min–max value). A total of 70 CO₂ and 71 O₂ tests were analysed. Results: The strongest and fastest CO₂ responders were control infants: their median increase in ventilation was 291%/kPaCO₂ and their reaction time 16 breaths. In infants with PBCA and OA, the increase in ventilation was 41% and 130%/kPaCO₂, and reaction time 64 and 54 breaths, respectively. There was a significant negative correlation between CO₂ response strength and response time. In response to hyperoxia there was a comparable decrease in ventilation in all infants (12–20%), but a significantly longer response time in infants with apnoea (20 v 12 breaths). There was no correlation between the response strength and response time to O₂ and CO₂. Conclusion: An inappropriate central control of respiration is an important mechanism in the pathogenesis of apnoea of infancy.     

Pulmonary interstitial emphysema in very low birthweight infants.

Forty six of 142 infants weighing less than 1500 g at birth, who had chest radiographs in the first 5 days of life, developed pulmonary interstitial emphysema (PIE) and in 19 this occurred in the first 24 hours. PIE was seen more frequently in infants weighing less than 1000 g at birth (24 of 57) than in those weighing 1000-1500 g (22 of 85). Ventilation for hyaline membrane disease was strongly associated with PIE, and only babies who were resuscitated, or ventilated, or had hyaline membrane disease developed the disorder. Most pneumothoraces were preceded by x-ray appearances of PIE (17 of 21). Mortality was increased in ventilated infants who developed PIE and was high in those with severe x-ray changes.     

Use of continuous positive airway pressure during stabilisation and retrieval of infants with suspected bronchiolitis

Aim: Infants with viral bronchiolitis are often hospitalised with a proportion requiring respiratory support. The aim of this review was to examine the use of nasal prong continuous positive airway pressure (CPAP) as a management strategy for infants with a diagnosis of bronchiolitis, who required stabilisation and transport to a tertiary centre. Method: A retrospective audit of infants with bronchiolitis requiring CPAP during transport between January 2003 and June 2007. Results: Nasal CPAP was initiated in 54 infants with 51 of these (34 ex‐preterm, 17 term) subsequently continuing on CPAP during retrieval. Mean CPAP pressure was 7 cmH₂O. Oxygenation improved between stabilisation and the end of retrieval (P < 0.01). During retrieval, there was no significant increase in transcutaneous CO₂, no infant required endotracheal ventilation and no adverse events were noted. Five infants were intubated within the first 24 h of admission at the receiving hospital. Conclusion: This review demonstrated that use of nasal prong CPAP to transport infants with bronchiolitis was a safe management strategy in those with moderate to severe disease severity.     

Chronic night cough and asthma severity in children with stable asthma

The relationship between night cough and other indices of asthma severity was studied in 21 children with clinically stable asthma and persistent night cough. Overnight cough was quantified and related to symptom scores, oxygen saturation (S_aO₂) during sleep, evening and morning peak flow recordings and daytime tests of lung function. In the index group the median number of coughing episodes was 23 (range 1–158). Only 4 children had counts of <10 overnight, similar to the comparison group of 12 children all of whom had counts of <10. There was a trend towards the association of overnight cough with reduced evening peak flow (r=–0.407,P=0.07) and reduced S_aO₂ (r=–0.36,P=0.10). Abnormalities in daytime tests of lung function were observed in 13 children. There was no relationship between night cough and daytime indices of lung function abnormality although children with more severe daytime abnormalities also had significant night cough. Conversely, five children with chronic night cough had normal daytime function.Conclusion Night-time cough in children with asthma is not simply a reflection of daytime lung function status, whereas, overnight S_aO₂ correlates well. Other factors need to be explored to explain the variability of night-time cough in these children.     

Inflation times during resuscitation of preterm infants

Data on the effects of a prolonged inflation time during the resuscitation of very prematurely born infants are limited; one study showed no effect, and in another, although lower bronchopulmonary dysplasia (BPD) rates were seen, that effect could have been due to the prolonged inflation time, the positive end expiratory pressure applied or the combination of the two. The aims of our study were to assess the length of inflation times used during face mask and t-piece resuscitation of prematurely born infants in the labour suite and determine whether prolonged inflations led to longer inflation flow times. A respiration monitor (NM3 respiratory profile monitor) was used to record flow, airway pressure and tidal volume changes. The first five inflations for each baby were analysed. Forty prematurely born infants (median gestational age 30, range 26–32 weeks) were examined. Their median inflation pressure was 17.6 (range 12.2–27.4) cm H₂O, inflation time 0.89 (range 0.33–2.92) s, expiratory tidal volume 1.01 (range 0.02–11.41) ml/kg and inflation flow time 0.11 (range 0.04–0.54) s. There was no significant relationship between the inflation time and the inflation flow time, but there was a significant relationship between the inflation pressure and the inflation flow time (p = 0.024). Conclusion: These results suggest that prolonging inflation times during face mask resuscitation of prematurely born infants would not improve ventilation as prolonged inflation did not lead to longer inflation flow times.     

Evaluation of triggering systems for patient triggered ventilation for neonates ventilator-dependent beyond 10 days of age

The performance of two triggering systems was compared during patient triggered ventilation (PTV) of infants ventilator-dependent beyond 10 days of age. Ten infants were studied who had a median gestational age of 26.5 weeks and a postnatal age of 15.5 days. PTV was administered via the SLE ventilator and the two triggering systems, an airway pressure monitor and the MR10 respiration monitor, were used in random order each for 30 min. The airway pressure trigger had a superior performance in that, although it did not differ significantly in delivered inflation volume or sensitivity to the MR10 respiration monitor, it had a shorter trigger delay (P<0.01). Oxygenation improved in eight of the ten infants on the airway pressure trigger, but only in three on the MR10 respiration monitor. The reduction in PaCO₂ was greater during PTV with the airway pressure trigger compared with the MR10 respiration monitor (P<0.01). We conclude that the airway pressure trigger has a superior performance compared to the MR10 respiration monitor trigger in infants who are ventilator-dependent beyond 10 days of age.     

A European multicenter randomized controlled trial of single dose surfactant therapy for idiopathic respiratory distress syndrome

We performed a multicenter prospective randomized controlled trial to determine the efficacy and safety of the surfactant preparation, Survanta (Abbott Laboratories, Chicago, USA), for 750–1750 g infants with idiopathic respiratory distress syndrome, (IRDS) receiving assisted ventilation with 40% or more oxygen. One hundred and six eligible infants from the eight participating centers were randomly assigned between March 1986 and June 1987 to receive either surfactant (100 mg phospholipid/kg, 4 ml/kg) or air (4 ml/kg) administered into the trachea within 8 h of brith (median time of treatment 6.2 h, range 3.2–9.1 h). The study was stopped before enrollment was completed at the request of the United States Food and Drug Administration when significant differences were observed in incidence of periventricular-intraventricular hemorrhage (PIH), between the surfactant treated and control infants. Surfactant treated infants had larger average increases in the arterial-alveolar oxygen ratio, (a/A ratio) (P<0.0001), and larger average decreases in FiO₂ (P<0.0001) and mean airway pressure, (MAP) (P<0.017) than controls over the 48 h following treatment. The magnitude of the differences between the surfactant and control groups were 0.19 (SE=0.03) for a/A ratio, –0.28 (SE=0.04) for FiO₂ and –1.7 cm H₂O (SE=0.70) for MAP. The clinical status on days 7 and 28 after treatment was classified using four predefined ordered categories: (1) no respiratory support; (2) supplemental O₂ with or without continuous positive airway pressure (CPAP); (3) intermittent mandatory ventilation; and (4) death. There were no statistically significant differences in the status categories on days 7 or 28 between surfactant and control infants. There were no significant differences between the groups with respect to the incidence of patent ductus arteriosus, bronchopulmonary dysplasia, necrotizing entero-colitis, air leaks or death. There was a statistically significant difference between treated and control infants in the frequency and severity of periventricular-intraventricular hemorrhage (PIH) (Cochran-Mantel-Haenszel ²adj=6.36,P=0.01). Hemorrhages occurred in 59.6% of surfactant treated infants and 26.9% of controls. Severe hemorrhages (grades 3 or 4) occurred in 38.5% of surfactant treated infants and 15.4% of controls ( ²adj=4.01,P=0.045). We conclude that the intratracheal administration of Survanta prior to 8 h of age to infants with IRDS receiving assisted ventilation with 40% or more oxygen results in a reduction in the severity of respiratory distress during the 48 h after therapy. Because of the difference in incidence of PIH between surfactant and control infants in this study, we recommend that future clinical trials of surfactant include more frequent prospective serial ultrasound evaluations for diagnosis of hemorrhage.     

猪肺表面活性物质气管内灌洗治疗重症新生儿胎粪吸入综合征的临床研究

目的 研究猪肺表面活性物质（PS）气管内灌洗治疗重症新生儿胎粪吸入综合征（MAS）的临床疗效。方法 2010 年1 月至 2013 年6 月收治的重症MAS 足月儿136 例, 随机分为PS 气管内灌洗治疗组（灌洗组）和PS 气管内注入治疗组（注入组）,每组68 例。灌洗组采用稀释后的PS 3~5 mL/次（12 mg/mL）气管内灌洗;注入组采用PS 原液200 mg/kg（首剂）气管内注入。比较两组患儿治疗前及治疗后2、12、24、48 h的血气分析、OI 值、P/F 值的动态变化,以及两组患儿的上机时间、并发症、治愈率。结果 灌洗组在PS 使用后的12 h、24 h、48 h PaO2、PaCO2、OI、P/F 值均优于注入组（PPPPP结论 PS 稀释后进行气管内灌洗在改善通气和氧合方面优于PS 气管内注入,并可减少上机时间,减少并发症,提高治愈率。     

Prediction of outcome from the chest radiograph appearance on day 7 of very prematurely born infants

Our aim was to determine whether the chest radiograph appearance at 7 days predicted chronic lung disease development (oxygen dependency at 36 weeks post-menstrual age) or death before discharge and if it was a better predictor than readily available clinical data. Two consecutive studies were performed. In both, chest radiographs taken at 7 days for clinical purposes were assessed using a scoring system for the presence of fibrosis/interstitial shadows, cystic elements and hyperinflation and data were collected regarding gestational age, birth weight, use of antenatal steroids and post-natal surfactant and requirement for ventilation at 7 days. Oxygenation indices were calculated in the first study (study A) at 120 h and in the second (study B) at 168 h. In study A, there were 59 infants with a median gestational age of 26 weeks (range 24 to 28 weeks) and in study B, 40 infants with a median gestational age of 27 weeks (range 25–31 weeks). In both studies, infants who developed chronic lung disease had a significantly higher total chest radiograph score, with a higher score for fibrosis/interstitial shadowing than the rest of the cohort. Infants who died before discharge differed significantly from the rest with regard to significantly higher scores for cysts. In both studies, the areas under the receiver operator characteristic curves with regard to prediction of chronic lung disease were higher for the total chest radiograph score compared to those for readily available clinical data. Conclusion:in infants who require a chest radiograph for clinical purposes at 7 days, the chest radiograph appearance can facilitate prediction of outcome of infants born very prematurely.Abbreviations CLD chronic lung disease - CXR chest radiograph - CMV conventional mechanical ventilation - HFO high frequency oscillation - KCH Kings College Hospital - OI oxygenation index - PIE pulmonary intestinal emphysema - PMA post-menstrual age - ROC receiver operator characteristic curves - UKOS United Kingdom Oscillation Study