Changes in dead space/tidal volume ratio and pulmonary mechanics after surfactant replacement therapy in respiratory distress syndrome of the newborn infants

This study was performed to elucidate the mechanism of improved oxygenation after surfactant replacement therapy in respiratory distress syndrome (RDS) of the newborn infants. In 26 newborns with RDS, end tidal-CO2 tension (PetCO2), arterial blood gas analysis and pulmonary function tests were measured at baseline, 30 min, 2 hr and 6 hr after surfactant administration. The changes in dead space/tidal volume ratio (VD/VT ratio=(PaCO2-PetCO2)/PaCO2), oxygenation index and arterial-alveolar partial pressure difference for oxygen ((A-a)DO2) were elucidated and correlated with pulmonary mechanics. Oxygenation index and (A-a)DO2 improved, and VD/VT ratio decreased progressively after surfactant administration, becoming significantly different from the baseline at 30 min and thereafter with administration of surfactant. Pulmonary mechanics did not change significantly during the observation period. VD/VT ratio showed close correlation with OI and (A-a)DO2, but not with pulmonary mechanics. These results suggest that decreased physiologic dead space resulting from the recruitment of atelectatic alveoli rather than improvement in pulmonary mechanics is primarily responsible for the improved oxygenation after surfactant therapy in the RDS of newborn.     

Massive pulmonary hemorrhage in newborn infants successfully treated with high frequency oscillatory ventilation.

Massive pulmonary hemorrhage (MPH) in newborn infants is a catastrophic event with a fatal result. The aim of this study was to assess the efficacy of high frequency oscillatory ventilation (HFOV) as a rescue therapy for MPH in newborn infants. Eighteen newborn infants with MPH refractory to conventional mechanical ventilation were treated with HFOV. Changes in oxygenation were assessed using arterial-alveolar oxygen tension ratio (a/APO2) and oxygenation index (OI) during HFOV. The most common underlying disorder of MPH was preterm patent ductus arteriosus (PDA). Thirteen out of 18 (72%) newborn infants with MPH responded to HFOV and survived. Five out of 18 (28%) did not respond to HFOV and died. There were no differences between responders and nonresponders in gestational age, birth weight, pre-HFOV OI, and age of MPH onset. In responders, there was a rapid increase in a/APO2 from 0.18+/-0.04 to 0.40+/-0.08 at 30 minutes after HFOV. There was also significant decrease in OI from 14.9+/-4.7 to 8.1+/-1.5 at 1 hour after HFOV. We conclude that HFOV shows rapid and dramatic improvements and has ultimately life-saving effects in MPH of newborn infants.     

经鼻间歇正压通气防治早产儿呼吸窘迫综合征的临床研究

目的探讨经鼻间歇正压通气(NIPPV)在防治早产儿呼吸窘迫综合征(RDS)中的应用价值。方法选择2017年6月至2018年12月梧州市人民医院RDS早产儿90例,其中男性48例,女性42例;胎龄(29.03±0.58)周;出生体质量(996.91±98.52)g;病程(3.48±0.56)h;临床分级Ⅰ级58例,Ⅱ级32例;Apgar评分(6.85±1.06)分。依据随机数字表分为NIPPV组和持续气道正压通气(NCPAP)组,每组45例。NIPPV组给予NIPPV治疗,NCPAP组给予NCPAP治疗,若两组治疗后不能维持患儿生命体征则使用肺表面活性物质(PS)或行有创机械通气。结果NIPPV组和NCPAP组治疗12、24 h后和治疗结束时动脉血氧分压(PaO2)、氧合指数(OI)明显高于治疗前。NIPPV组治疗12、24 h后PaO2、OI明显高于NCPAP组,差异有统计学意义(P<0.05)。NIPPV组和NCPAP组治疗结束时PaO2、OI比较,差异无统计学意义(P>0.05);NIPPV组PS使用率(22.22%vs 44.44%)、有创通气率(17.78%vs 40.00%)、氧疗时间[(71.42±7.62)h vs(85.62±9.24)h]、有创通气时间[(46.78±5.32)h vs(55.27±6.14)h]、住院时间[(30.42±3.65)d vs(35.62±3.89)d]、并发症率(31.11%vs 53.33%)明显低于NCPAP组,差异有统计学意义(P<0.05)。结论NIPPV可有效改善RDS早产儿通气功能,有利于减少PS使用、有创通气及并发症,值得临床推广。     

高频振荡通气治疗新生儿呼吸衰竭的对比性研究

目的探讨高频震荡通气对新生儿重症呼吸衰竭治疗的疗效。方法对比分析36例新生儿重症呼吸衰竭使用传统机械通气失败后改用高频震荡通气治疗前后动脉血氧分压（PaO2）,二氧化碳分压（PCO2）,血氧饱和度（SaO2）,动脉血氧分压与吸入氧浓度之比（PaO2/FiO2）,动脉-肺泡氧张力比值（a/APaO2）,氧合指数（oxygenation index,OI）。结果改高频通气治疗后二氧化碳分压（PaCO2）、氧合指数（OI）下降,（P〈0.01）。动脉血氧分压（PaO2）、动脉血氧分压与吸入氧浓度之比（PaO2/FiO2）、动脉-肺泡氧张力比值（a/APaO2）上升,（P〈0.01）。结论高频震荡通气能更好地改善重症呼吸衰竭新生儿的通气和气体交换,减少气压伤,对治疗新生儿重症呼吸衰竭具有较好的疗效。     

Modified bovine surfactant (Survanta) versus a protein-free surfactant (Exosurf) in the treatment of respiratory distress syndrome in preterm infants: a pilot study.

We undertook a prospective, randomized, non-blinded pilot study to determine whether infants with respiratory distress syndrome (RDS) who were treated with protein-containing bovine surfactant (Survanta, Ross/Abbott Laboratories, Columbus, Ohio) had earlier and larger responses in gas exchange when compared with similar infants treated with a synthetic surfactant (Exosurf, Burroughs Wellcome, Research Triangle Park, North Carolina). Forty-one infants weighing between 600 g and 1750 g at birth with RDS of sufficient severity to require assisted ventilation with an FiO2 > 0.39 were enrolled in the study and treated with surfactant from 1 to 8 hours after birth. Infants were randomly selected to receive treatment with either Exosurf or Survanta. Despite randomization, the Survanta group was overrepresented with factors associated with greater severity of RDS (lower birthweight, more males, and fewer African Americans). No statistically significant difference was found in the primary outcome measure (arterial/alveolar PaO2 > 0.3 at 24 hours) by univariate or multivariate analysis. The percentage of responders in the Survanta-treated group was significantly increased 24 hours after treatment in two of four secondary measures of oxygenation when analyzed by univariate tests using one-tailed P values. Based on these results, we anticipate that acute outcomes after Survanta or Exosurf will approximate those found in this trial and that differences in measures of oxygenation between treatment groups will approximate 30% to 50% 24 hours after initial treatment.     

PMEA coating of pump circuit and oxygenator may attenuate the early systemic inflammatory response in cardiopulmonary bypass surgery

We investigated the effects of coating a cardiopulmonary bypass (CPB) circuit and oxygenator with poly-2-methoxy-ethyl acrylate (PMEA) on the systemic inflammatory response during and after CPB. Thirty patients undergoing elective cardiac surgery were randomized into three groups (each group n = 10): noncoated (group N), heparin coated (group H), and PMEA coated circuit and oxygenator (group X). Bradykinin (BK), complement 3 activation (C3a) and interleukin-6 (IL-6) levels were measured as early phase indicators of inflammatory response, as were maximum C reactive proteins (CRP) and white blood cell (WBC) levels. The alveolar-arterial oxygen gradient (A-a DO2) was measured as a parameter of respiratory function. IL-6 levels after CPB were significantly higher in group N than in groups H and X (p < 0.05). Serum BK and C3a levels showed similar patterns in all groups. A-a DO2 was lower at the end of and 3 hours after CPB in groups H and X than in group N (p < 0.05). Maximum CRP levels were lower in group X than in groups N (p < 0.05). This prospective study suggests that PMEA coated CPB may improve respiratory function and decrease systemic inflammatory response after cardiac surgery, possibly because this circuit is as biocompatible as heparin coated CPB circuit.     

Neonatal ventilatory techniques – which are best for infants born at term?

Few studies have examined ventilatory modes exclusively in infants born at term. Synchronous intermittent mandatory ventilation (SIMV) compared to intermittent mandatory ventilation (IMV) is associated with a shorter duration of ventilation. The limited data on pressure support, volume targeted ventilation and neurally adjusted ventilatory assist demonstrate only short term benefits in term born infants. Favourable results of high-frequency oscillatory ventilation (HFOV) in infants with severe respiratory failure were not confirmed in the two randomised trials. Nitric oxide (NO) in term born infants, except in those with congenital diaphragmatic hernia (CDH), reduces the combined outcome of death and requirement for extracorporeal membrane oxygenation (ECMO). In infants with severe refractory hypoxaemic respiratory failure, ECMO, except in infants with CDH, reduced mortality and the combined outcome of death and severe disability at long-term follow-up. Randomised studies with long term outcomes are required to determine the optimum modes of ventilation in term born infants.     

小儿Denis Browne微创小切口心内直视手术对肺功能的影响

目的观察小儿体外循环心内直视手术采用右腋下Denis Browne微创小切口径路对肺功能的影响。方法选择2004年3月至2006年5月间60例小儿先天性心脏病患者,按切口方式分为右腋下Denis Browne微创小切口径路组（右侧切口组）和正中切口组,每组各30例。均在体外循环下完成心内直视手术,根据在麻醉诱导后、体外循环转流前、主动脉开放心脏复跳时、关胸前、术后30min、4h、2h7个时间点的血气分析结果及给氧浓度计算氧合指数（Oxygenation index,OI）、肺泡-动脉血氧分压差（Alveolararterial oxygen tension gradient,P（A-a）O2）、呼吸指数（respiratory index,RI）,并观察呼吸机辅助时间、气管导管拔除后呼吸情况的改变,包括自主呼吸频率、有无呼吸困难、肺部哕音、紫绀以及动脉氧血红素饱和度、脉动氧血红素饱和度变化。结果两组均在体外循环下完成心内直视手术,无手术死亡,无严重并发症,术后均恢复良好。两组患儿OI均较术前降低,P（A-a,O2、RI较术前升高,两组患儿间无统计学意义;呼吸机辅助时间、气管导管拔除后呼吸情况的改变两组患者间无统计学意义。结论小儿体外循环心内直视手术采用右腋下Denis Browne微创小切口不加重术后肺功能的损伤。     

A comparison of clinical efficacy between high frequency oscillatory ventilation and conventional ventilation with lung volume recruitment in pediatric acute respiratory distress syndrome: A randomized controlled trial

Purpose:

To determine the efficacy of lung volume recruitment maneuver (LVRM) with high frequency oscillatory ventilation (HFOV) on oxygenation, hemodynamic alteration, and clinical outcomes when compared to conventional mechanical ventilation (CV) in children with severe acute respiratory distress syndrome (ARDS).

Materials:

We performed a randomized controlled trial and enrolled pediatric patients who were diagnosed to have severe ARDS upon pediatric intensive care unit (PICU) admission. LVRM protocol combined with HFOV or conventional mechanical ventilation was used. Baseline characteristic data, oxygenation, hemodynamic parameters, and clinical outcomes were recorded.

Results:

Eighteen children with severe ARDS were enrolled in our study. The primary cause of ARDS was pneumonia (91.7%). Their mean age was 47.7 ± 61.2 (m) and body weight was 25.3 ± 27.1 (kg). Their initial pediatric risk of mortality score 3 and pediatric logistic organ dysfunction were 12 ± 9.2 and 15.9 ± 12.8, respectively. The initial mean oxygen index was 24.5 ± 10.4, and mean PaO₂/FiO₂ was 80.6 ± 25. There was no difference in oxygen parameters at baseline the between two groups. There was a significant increase in PaO₂/FiO₂ (119.2 ± 41.1, 49.6 ± 30.6, P = 0.01*) response after 1 h of LVRM with HFOV compare to CV. Hemodynamic and serious complications were not significantly affected after LVRM. The overall PICU mortality of our severe ARDS at 28 days was 16.7%. Three patients in CV with LVRM group failed to wean oxygen requirement and were cross-over to HFOV group.

Conclusions:

HFOV combined with LVRM in severe pediatric ARDS had superior oxygenation and tended to have better clinical effect over CV. There is no significant effect on hemodynamic parameters. Moreover, no serious complication was noted.     

Clinical response to inhaled nitric oxide in persistent pulmonary hypertension of the newborn.

We observed clinical response to inhaled nitric oxide (iNO) in 12 neonates with persistent pulmonary hypertension of the newborn (PPHN). Clinical response was defined as a decrease in oxygenation index (OI) by 40%. Ten of 12 neonates had response to iNO showing decrease OI from 46.1+/-7.6 to 14.4+/-6.8 at 1 hour after inhalation. Sustained improvement of OI was achieved in 8 neonates and two neonates were relapsed. In the group of neonates who had OI above 40 (n=7), 6 of them showed the decrease of OI from 66.1+/-4.8 to 18.3+/-8.0 at 1 hour. In two groups, one had OI of 40 or greater, and the other OI of 40 or less, there were no differences in pattern of response and early death rate. The response rates according to underlying diseases were as follows; idiopathic PPHN 100%, respiratory distress syndrome 100%, and diaphragmatic hernia 66.7%. Relapse was observed in one neonate with sepsis caused by pneumonia and in one infant with meconium aspiration syndrome. Two infants showed no response to iNO (one diaphragmatic hernia and one suspected pulmonary hypoplasia). We conclude that iNO therapy could improve oxygenation in high percentage of newborn infants with severe PPHN of various underlying conditions except pulmonary hypoplasia.     

Factors affecting the response to inhaled nitric oxide therapy in persistent pulmonary hypertension of the newborn infants

Persistent pulmonary hypertension of the newborn infant (PPHN), is a clinical syndrome characterized by elevated pulmonary vascular resistance, resulting from reactive vasoconstriction or structural remodeling of the pulmonary vasculature. Although inhaled nitric oxide (iNO) has emerged as a novel selective treatment of PPHN, responses to iNO are variable according to the etiologies or the clinical situation. A retrospective chart review of 51 newborn infants with PPHN and treated with iNO, was undertaken to evaluate the factors affecting response to iNO. Response to iNO was defined as a reduction in the oxygenation index (OI) of more than 20%, or disappearance of the difference in oxygen saturation between preductal and postductal circulation after iNO therapy. The patients were divided into two groups; the responder group and the non- responder group. Respiratory distress syndrome (RDS) was more commonly associated with PPHN in the responder group than in the non-responder group (p < 0.05), while there were many more patients with congenital diaphragmatic hernia (CDH) in the non-responder group than in the responder group (p < 0.05). Infants with meconium aspiration syndrome (MAS) were similar in both of the two groups. Initial OI, initial mean airway pressure (MAP), and initial and peak NO concentration were significantly lower in the responder group compared to the non-responder group (p < 0.05). Rapid response (response to iNO within the first hour) was shown in 74% of the responder group and 33% of the nonresponder group (p < 0.05). There was no significant differences in the initial chest radiographic findings, such as normal, focal or bilateral diffuse infiltration, with the exception of CDH, between each group. Lower initial OI, lower initial MAP and significant response within the first hour were shown to be favourable factors in response to iNO therapy. Patients with RDS associated with PPHN responded much better to iNO than those with other diseases.     

Oxygenation index for extracorporeal membrane oxygenation: is there predictive significance?

Although extracorporeal membrane oxygenation (ECMO) is known to improve survival in neonates with respiratory failure, there has been a significant decrease in the use of ECMO in recent years. Alternative modalities such as high-frequency oscillatory ventilation (HFOV), inhaled nitric oxide (iNO), and surfactant therapy are associated with this decline. The criteria for the initiation of ECMO, developed about 20 years ago, are likely no longer relevant. We examined the predictive significance of the oxygenation index (OI) as a patient entry criterion for ECMO use. We sought a critical OI level predicting death or chronic lung disease (CLD) with and without ECMO use. We also examined whether patients with certain OIs are more likely to have worse outcomes. One hundred and seventy-four term-newborn admissions between 1995 and 2000 requiring mechanical ventilation were enrolled in the study. Receiver operating curve analysis was performed to find a cutoff value of OI for ECMO initiation. Mortality rates and CLD probability were compared to the worst OIs. Our 6-year ECMO administration experience showed that an OI of 33.2 is a suitable cutoff value for ECMO initiation with high sensitivity and specificity as a predictive criterion. The critical OI value associated with the CLD risk when ECMO is not used is in the 40s. OI is a good predictor of CLD; the probability of CLD increases with higher OIs. Our data support the trend toward the use of new interventions over ECMO, especially for patients with OI scores of less than 33.2. Only when the probability of ventilator-associated lung injury becomes significant is it better to consider ECMO than conventional modalities.     

A controlled trial of synthetic surfactant in infants weighing 1250 g or more with respiratory distress syndrome. The American Exosurf Neonatal Study Group I, and the Canadian Exosurf Neonatal Study Group

BACKGROUND. Surfactant-replacement therapy is now recognized as a life-saving and safe intervention in small premature infants, but there is little evidence concerning its risks and benefits in larger premature infants. METHODS. We conducted a placebo-controlled, blinded trial in 1237 infants with respiratory distress who were enrolled at 23 hospitals in the United States and 13 hospitals in Canada. At entry all the infants weighed at least 1250 g, were receiving mechanical ventilation, and had a ratio of arterial to alveolar oxygen tension below 0.22. The initial dose of either the synthetic surfactant (Exosurf, 5 ml per kilogram of body weight) or air (the placebo) was administered less than 24 hours after birth, with a second dose given 12 hours later. A total of 614 infants were assigned to receive surfactant, and 623 to receive placebo. RESULTS. Fewer infants in the surfactant group than in the placebo group died before 28 days of age or survived at 28 days with bronchopulmonary dysplasia (7 percent vs. 12 percent, P = 0.002). In the first 28 days of life, there were fewer deaths due to respiratory distress syndrome in the surfactant group (1 percent vs. 3 percent, P = 0.043), lower overall neonatal mortality (4 percent vs. 7 percent, P = 0.04), and a lower incidence of bronchopulmonary dysplasia (3 percent vs. 6 percent, P = 0.008). There was also a significantly lower incidence of pulmonary air leaks, intraventricular hemorrhage, patent ductus arteriosus, seizures, hypotension, and pulmonary hypertension in the surfactant group. The infants treated with surfactant were weaned from oxygen and mechanical ventilation significantly sooner than those given placebo, and they less often required high-frequency ventilation or extracorporeal membrane oxygenation. The primary side effect observed more frequently among the infants who received surfactant treatment was pulmonary hemorrhage (six infants vs. one infant, P = 0.055). CONCLUSIONS. In infants weighing at least 1250 g at birth who have respiratory distress syndrome, treatment with two doses of synthetic surfactant improves survival and reduces perinatal morbidity.     

Comparison of clinical efficacy of Newfactan versus Surfacten for the treatment of respiratory distress syndrome in the newborn infants

Newfactan is a domestically developed, bovine lung-derived, semi-synthetic surfactant. The aim of this study was to compare the clinical efficacy of Newfactan with that of Surfacten in the treatment of respiratory distress syndrome (RDS). Newfactan or Surfacten was randomly allocated to 492 newborn infants who were diagnosed as RDS and required surfactant instillation in four participating hospitals. The comparisons were made individually in two subsets of infants by birth weight (<1,500 g group [n=253] and > or =1,500 g group [n=239]). Short-term responses to surfactant and acute complications, such as the total doses of surfactant instilled, response type, extubation rate, ventilator settings, changes in respiratory parameters, air leak, patent ductus arteriosus, pulmonary hemorrhage, and intraventricular hemorrhage, and mortality during the 96 hr after surfactant instillation were measured. Long-term outcome and complications, such as total duration of intubation, bronchopulmonary dysplasia and periventricular leukomalacia, and ultimate mortality were measured. There were no significant differences in demographic and perinatal variables, shortterm responses to surfactant and acute complications, and long-term outcome and complications between Newfactan and Surfacten in both birth weight groups. We concluded that Newfactan was comparable to Surfacten in the clinical efficacy in the treatment of RDS in both birth weight groups.     

Vitamin D deficiency and its effect on respiratory distress syndrome in premature infants: results from a prospective study in a tertiary care centre

BackgroundThe positive effects of steroids on lung development are well known, and 1,25-dihydroxy vitamin D₃ has been shown to exert positive effects on fetal lung development.ObjectiveWe aimed to investigate the relationship between 25-hydroxyvitamin D [25(OH)D] levels and respiratory distress syndrome (RDS) in premature infants.MethodsInfants aged ≤32 gestational weeks who were admitted to the neonatal intensive care unit (NICU) during 1 year were enrolled in this prospective study. 25(OH)D levels were obtained at the time of admission to NICU. Patients were divided into three groups according to their 25(OH)D levels: severe (group 1), moderate (group 2), and mild (group 3) 25(OH)D deficiencies.ResultsThe study comprised 72 patients; of them, RDS was observed in 49 and not observed in 23 patients. The mean 25(OH)D levels were significantly lower in RDS patients (p=0.04). Multivariate analysis showed that patients with higher 25(OH)D levels can be preventive for the development of RDS (odds ratio 0.89; 95% confidence interval 0.8–0.99; p=0.04).ConclusionOur study revealed that 25(OH)D deficiency is an independent risk factor for RDS in premature infants. However, further studies are necessary to explore the association between 25(OH)D deficiency and RDS.     

Cerebral oxygenation and cerebral oxygen extraction in the preterm infant: the impact of respiratory distress syndrome

Haemodynamic factors play an important role in the etiology of cerebral lesions in preterm infants. Respiratory distress syndrome (RDS), a common problem in preterms, is strongly related with low and fluctuating arterial blood pressure. This study investigated the relation between mean arterial blood pressure (MABP), fractional cerebral oxygen saturation (ScO₂) and fractional (cerebral) tissue oxygen extraction (FTOE), a measure of oxygen utilisation of the brain, during the first 72 h of life. Thirty-eight infants (gestational age < 32 week) were included, 18 with and 20 without RDS. Arterial oxygen saturation (SaO₂), MABP and near infrared spectroscopy-determined ScO₂ were continuously measured. FTOE was calculated as a ratio: (SaO₂–ScO₂)/SaO₂. Gestational age and birth weight did not differ between groups, but assisted ventilation and use of inotropic drugs were more common in RDS infants (P<0.01). MABP was lower in RDS patients (P<0.05 from 12 up to 36 h after birth), but increased in both groups over time. ScO₂ and FTOE were not different between groups over time, but in RDS infants ScO₂ and FTOE had substantial larger variance (P<0.05 at all time points except at 36–48 h for ScO₂ and P<0.05 at 12–18, 18–24, 36–48 and 48–60 h for FTOE). During the first 72 h of life, RDS infants showed more periods of positive correlation between MABP and ScO₂ (P<0.05 at 18–24, 24–36 36–48 48–60 h) and negative correlation between MABP and FTOE (P<0.05 at 18–24, 36–48 h). Although we found that the patterns of cerebral oxygenation and extraction in RDS infants were not different as compared to infants without RDS, we suggest that the frequent periods with possible lack of cerebral autoregulation in RDS infants may make these infants more vulnerable to cerebral damage.     

足月新生儿呼吸窘迫综合征危险因素及肺表面活性物质疗效评估

目的 探讨足月新生儿呼吸窘迫综合征（RDS）的危险因素,观察肺表面活性物质（PS）的疗效,为足月儿RDS的防治提供依据.方法 选取2007年1月至2011年12月郑州大学第三附属医院NICU收治的足月儿RDS为RDS组,以同期入院的非RDS足月儿为对照组,对两组性别、胎龄、分娩方式、宫内窘迫、出生窒息、母亲妊高症、糖尿病、胎膜早破进行单因素方差分析和Logistic多因素回归分析;并以RDS组中是否给予PS治疗分为应用PS亚组和未应用PS亚组,评估PS的疗效.结果 RDS组和对照组各106例进入分析.①RDS组发病时间为生后5 min至18 h,平均（4.9±3.4）h,其中生后6 h内发病87例（82.1%）,～12 h 16例（15.1%）,〉12 h 3例（2.8%）;X线胸片分级Ⅰ级28例（26.4%）,Ⅱ级36例（34.0%）,Ⅲ级23例（21.7%）,Ⅳ级19例（17.9%）;②Logistic回归分析显示男性（OR=10.35,95%CI：1.94～15.26）、胎龄〈39周（OR=6.59,95%CI：2.33～36.51）、剖宫产（OR=7.26,95%CI：11.61～23.22）、择期剖宫产（OR=13.14,95%CI：3.55～21.84）和出生窒息（OR=4.33,95%CI：2.74～27.39）是足月儿RDS的危险因素;③应用PS亚组72例,未应用PS亚组34例.机械通气发生率、机械通气天数、氧疗时间、住院天数和呼吸机相关性肺炎发生率应用PS亚组均显著低于未应用PS亚组（P〈0.05）;两亚组气胸、肺出血、持续性肺动脉高压和动脉导管未闭发生率差异均无统计学意义（P〉0.05）.结论 男性、胎龄〈39周、剖宫产尤其是无医学指征的择期剖宫产、出生窒息是足月儿RDS的危险因素,PS治疗足月儿RDS疗效较好.     

Plasma soluble intercellular adhesion molecule-1 (sICAM-1) in pediatric ARDS during high frequency oscillatory ventilation: a predictor of mortality

Soluble intercellular adhesion molecule-1 (sICAM-1), an important adhesion molecule that mediates leukocyte-endothelial interaction, has been identified as a marker for the outcome of acute respiratory tract infection. We postulate that plasma ICAM-1 may be a valuable marker for both biological and clinical severity of acute respiratory distress syndrome (ARDS). Sixteen pediatric patients (> 1 month and < 15 years of age) diagnosed with ARDS were recruited from the Pediatric Intensive Care Unit at King Chulalongkorn Memorial University Hospital, Bangkok. The patients were randomized to receive either high frequency oscillatory ventilation (HFOV) or conventional mechanical ventilation. Plasma sICAM-1 was measured by enzyme linked immunosorbent assay (ELISA) on days 1, 3, 5 and 7 of ARDS. Plasma sICAM-1 levels in survivors and non-survivors of the HFOV and conventional treatment groups were compared. Nine and 7 patients constituted the control group receiving conventional treatment and HFOV group, respectively. Overall nine patients survived. The patients in the HFOV group had a better chance of survival compared to the controls (71% versus 31.5%), but it was not statistically significant (p = 0.2). The overall mortality was 45.7%. The mean plasma sICAM-1 levels (n = 13/16) were significantly elevated among non-survival patients as compared to survival patients at all time points, which indicates that an unfavorable outcome in ARDS is related to the degree of epithelial and endothelial alveolar cell injury. The elevation of plasma slCAM-1 on day 3 provided the best predictor of mortality (likelihood ratio 11.9, p < 0.001). It was concluded that HFOV facilitated a potentially better outcome compared to conventional treatment and it was associated with less lung injuries evidenced by lower plasma sICAM-1.     

Effect of intrauterine cocaine exposure on respiratory distress syndrome in very low birthweight infants.

To evaluate the effect of intrauterine cocaine exposure on lung maturity of very low birthweight infants, the medical records of all infants with birthweight < 1500 g born between January 1989 and December 1990 at DC General Hospital were reviewed. Infants with conditions known to cause lung maturity, severe congenital anomalies, proven early sepsis, and birthweight > or = 500 g were excluded. A total of 69 infants were included in the study. Chest roentgenograms of these infants were evaluated by a pediatric radiologist, who was unaware of the infant''s medical course, for evidence of respiratory distress syndrome (RDS), and radiological findings were correlated with clinical signs. Forty infants were exposed to cocaine in utero (cocaine group) and 29 were not exposed (noncocaine group). African-American ethnicity, pregnancy-induced hypertension, prolonged rupture of membranes, and alcohol use were similar in both groups. Tobacco use among cocaine group mothers was higher (42.5% versus 13.8%; P = .01). Gestational age (28.3 +/- 2.8 versus 28.3 +/- 3 weeks), birthweight (966 +/- 282 versus 1059 +/- 295 g), male gender, and Apgar scores were similar in both groups. Thirty (75%) infants in the cocaine group developed RDS compared with 19 (66%) in the noncocaine group (P > .05). Using multiple logistic regression analysis and controlling for smoking, alcohol use, and prolonged rupture of membranes (24 to 72 hours), the incidence of RDS between the groups remained statistically insignificant. We conclude that intrauterine cocaine exposure does not alter the incidence of RDS in very low birthweight infants.     

不同剂量牛肺表面活性物质治疗晚期早产儿 呼吸窘迫综合征的临床研究

目的 研究不同剂量牛肺表面活性物质治疗晚期早产儿呼吸窘迫综合征的临床疗效。方法 选取2016年1月~2018年1月在我院诊治的90例晚期早产儿呼吸窘迫综合征患儿,依据使用药物剂量分为观察组和对照组,每组45例。对照组给予标准剂量70 mg/kg,观察组给予100 mg/kg,对比两组患儿用药后5 h、10 h、20 h、40 h MAP、FiO2,PCO2、OI、PO2、通气时间以及并发症发生率。结果 观察组用药后5 h、10 h、20 h、40 h MAP、FiO2低于对照组,差异有统计学意义（P＜0.05）;观察组PCO2、OI均低于对照组,PO2高于对照组,通气时间短于对照组,差异有统计学意义（P＜0. 05）;观察组并发症发生率为8.89%,低于对照组的20.00%,差异具有统计学意义（P＜0.05）。结论 临床采用牛肺表面活性物质治疗晚期早产儿呼吸窘迫综合征,剂量应满足100 mg/kg,可有效缩短通气时间,改善肺顺应性,降低并发症的发生,临床安全性良好。