Incidence of apnoea and bradycardia in preterm infants following DTPw and Hib immunization: A prospective study

Objective: To evaluate the incidence and severity of apnoea and bradycardia in hospitalized preterm infants following immunization at 2 months of age, and identify risk factors.
Methodology: A prospective study of 98 preterm infants, of gestational age 24–31 weeks, immunized at approximately 2 months post natal age with diphtheria-tetanus-whole cell pertussis vaccine (DTP_w) in the neonatal intensive care unit (NICU) at King George V Hospital Sydney. Half the infants also received Haemophilus influenzae type b conjugate vaccine (Hib) simultaneously. All infants were monitored for apnoea and bradycardia in the 24 h periods pre- and post immunization.
Results: Only one infant had apnoea and/or bradycardia pre-immunization compared with 17 post immunization. For 12 infants these events were brief, self-limiting and not associated with desaturations (oxygen saturation <90%). However, for five infants (30%) these events were associated with oxygen desaturation and two of these infants required supplemental oxygen. The group that had apnoea and/or bradycardia and the group that did not were not significantly different in terms of gestational age, birth weight and other variables. Infants who received Hib together with DTP_w were less likely to have apnoea and/or bradycardia than those given DTP_w alone.
Conclusion: When considering immunization for preterm infants, the benefits of early immunization must be balanced against the risk of apnoea and bradycardia. We recommend that the cardio-respiratory function of hospitalized infants born at less than 31 weeks gestation be monitored for 48 h post immunization.     

Adverse reactions to immunization with newer vaccines in the very preterm infant

OBJECTIVE: To study the frequency and types of adverse reactions to currently available vaccines in very preterm infants. METHODS: Case notes were obtained for very preterm infants < or =30 weeks' gestational age who received their first immunization at the Royal Women's Hospital, Melbourne, during 1999-2003. Data were extracted for the time periods 48 h before and 48 h after immunizations, with the data extraction blinded as to whether the period being evaluated was pre- or post-immunization. Data collected focused on the frequency and severity of apnoea, respiratory support, fever and clinical consequences of adverse reactions. RESULTS: A total of 48 very preterm infants were immunized during the period; 37 infants had Comvax (Haemophilus influenzae type B and hepatitis B vaccine), Infanrix (diphtheria, tetanus and acellular pertussis vaccine) and inactivated poliomyelitis vaccine, and 11 infants had Comvax and Infanrix only. Their mean (SD) gestational age at birth was 26.4 (1.7) weeks with mean birthweight of 872 (235) g. The mean postnatal age at immunization was 76 (20) days. Low-grade fever (>37.5 degrees C per axilla) occurred in 16 (33%) infants after immunization, but none before immunization (P < 0.001). There was no substantial change in recorded apnoea. No serious adverse events were noted. Four (8%) infants underwent a septic work up post-immunization. The C-reactive protein was increased in all four infants, but other tests for sepsis were negative. CONCLUSION: Fever remains a common adverse event following immunization of the preterm infant in spite of the development of a new generation of vaccines.     

Response of preterm infants to diphtheria-tetanus-pertussis vaccine

The American Academy of Pediatrics recommendation that immunization of preterm infants with diphtheria-tetanus-pertussis (DTP) vaccine should begin at 2 months after birth, regardless of gestational age, is based on limited data. A prospective study was conducted to determine the immunogenicity and safety of DTP vaccine in preterm infants. One hundred ten preterm and 146 full term infants received doses of DTP at 2, 4 and 6 months after birth. Adjusted analysis of the antibody responses indicated that after three doses mean titers among preterm infants to each vaccine component were comparable to those of full term infants. Adjusted analysis of the incidence of adverse events indicated that the risk of adverse events in preterm infants was not significantly higher than that in full term infants. DTP vaccine is immunogenic and safe in preterm infants when the series is initiated at 2 months after birth, and this study supports the current recommendation of the American Academy of Pediatrics.     

Clinical spectrum of neonatal apnoea in very low birthweight infants

Abstract This study quantifies apnoea and assesses the response to xanthine derivatives amongst 172 consecutively born, surviving very low birth weight (VLBW) infants, 136 appropriate weight for gestational age (AGA), 36 small for gestatfonal age (SGA). All babies had electronic monitoring of heart and respiratory rates and nursing staff recorded episodes of apnoea (> 10 s), bradycardia (<100) and cyanosis. Only 42 (24.2%) babies had no episodes recorded. (25 AGA, 17 SGA). Sixty-four (37.2%) received active resuscitation on at least one occasion with six babies ventilated by bag and mask on more than 10 occasions. Apnoea had commenced by day 10 of life in all the babies who had apnoea and persisted beyond day 50 in only six; however four of these infants were still requiring active resuscitation. Apnoea had ceased by 37 weeks post-conceptual age in 88% and by 40 weeks in all but three babies.
Risk factor analysis revealed a strong correlation (P<0.005) with lower gestational ages and birth weights, respiratory distress syndrome (RDS) and the problems associated with it, such as mechanical ventilation, patency of the ductus arteriosus (PDA) and chronic neonatal lung disease. A single, reversible cause for apnoea was rarely demonstrated. Care must be exercised with feeding, physiotherapy and suctioning the pharynx and trachea of 'at risk' infants. Xanthine derivatives were highly effective in decreasing the frequency of recurrent apnoea from a mean of 10.08 episodes one day before, to 1.83 two days after commencement of treatment.     

Apnoea and bradycardia in preterm infants following immunisation with pentavalent or hexavalent vaccines

There is a lack of data regarding the incidence and clinical significance of apnoea or bradycardia (AB) following immunisation with combination vaccines containing an acellular pertussis (Pa) component in respiratory stable preterm infants. Medical records of respiratory stable preterm infants who received a first dose of a combined diphtheria (D) and tetanus (T) toxoids, Pa, Haemophilus influenzae type b (Hib), inactivated poliovirus (IPV) vaccine with or without hepatitis B virus (HBV) in the neonatal intensive care unit (NICU) of the University Childrens Hospital Basel between January 2000 and June 2003 were analysed. For each infant, clinical data were recorded for a 72 h period before and after immunisation. Of 53 infants with a mean gestational age of 28 weeks, 7 (13%) showed a transient recurrence of or increase in episodes of AB following immunisation. Five of these seven infants required intervention ranging from tactile stimulation to bag and mask ventilation. Regarding risk factors, children with recurrent or increased AB were indistinguishable from those without such events. The rate of fever (>38°C) following immunisation was higher in affected infants compared to those without recurrence of or increase in AB (3/7 vs 2/46, P =0.01). Conclusion:Although most infants tolerated immunisation well, the incidence of recurrent or increased apnoea or bradycardia in respiratory stable preterm infants following the first immunisation with penta- or hexavalent vaccines was 13%. Most apnoea or bradycardia events required intervention but did not have serious consequences. Monitoring of all preterm infants following immunisation in the neonatal intensive care unit is recommended.     

Effect of blood transfusion on apnoea, bradycardia and hypoxaemia in preterm infants

We studied the effect of blood transfusion on the frequency of apnoea, bradycardia and hypoxaemia in 21 spontaneously breathing preterm infants with a median gestational age at birth of 28 (range 23–31) weeks. Age at time of study was 22 days (3–84), weight 925 g (640–2120). The patients exhibited frequent episodes of bradycardia and/or hypoxaemia and were anaemic (median haemoglobin level 109 (82–120) g/l). One infant received two transfusions and was thus studied twice. Four-hour recordings of pulse oximeter saturation (SpO₂), pulse waveforms, transcutaneous oxygen pressure, electrocardiogram, breathing movements and nasal airflow were performed immediately before and after transfusion, and again after a further interval of 12 h. Recordings were analysed for isolated and periodic apnoeas (> 4 s), bradycardias (heart rate < 2/3 of baseline), and episodic desaturation (SpO₂≤ 80%). There were no significant changes in the frequency, severity and/or duration of apnoea, bradycardia or desaturation following transfusion. The average SpO₂ nadir reached during each desaturation, however, increased by 3% following transfusion (P < 0.05), and there was a trend towards shorter desaturations. Conclusion The occurrence of frequent episodes of apnoea, bradycardia and/or hypoxaemia does not, on its own, justify a blood transfusion in moderately anaemic preterm infants. Received: 25 July 1996 / Accepted: 24 September 1996     

Neonatal and neurodevelopmental outcome in infants born before 30 weeks of gestation with absent or reversed end-diastolic flow velocities in the umbilical artery

The objective of our study was to examine the outcome of infants born at a gestational age <30 weeks with absent or reversed end-diastolic flow velocity (AREDFV) in the umbilical artery in comparison with gestational age-matched eutrophic controls. A group of 40 infants who had AREDFV were matched for gestational age and date of birth with 40 appropriate for gestational age infants. Perinatal outcome variables were retrospectively reviewed. In 16 out of the 40 matched pairs, a standardized neurological examination was done and, depending on age, the Kaufman Assessment Battery for Children or the Bayley Scales of Infant Development were applied at a corrected age of 13 to 100 months to assess neurodevelopmental outcome. The results were compared using Fisher's Exact Test or Mann Whitney U Tests as appropriate. In the AREDFV group, 26/40 (65%) survived until discharge compared to 39/40 (97.5%) in the control group (P < 0.001). AREDFV was associated with a higher rate of chronic lung disease, retinopathy of prematurity ≥ grade III and impaired intestinal motility. More AREDFV infants suffered from permanent neurological sequelae compared with control infants: 44% versus 25% were mentally retarded (P=0.033), and 38% versus 19% showed severe motor impairment (P=0.073). Conclusion Absent or reversed end-diastolic flow velocity is not only associated with a higher mortality and morbidity during the neonatal period, but the surviving infants of this high risk group have an increased risk for mental retardation and severe motor impairment as compared with appropriate for gestational age preterm infants of the same gestational age. Received: 24 July 2000 and in revised form: 25 September 2000 / Accepted: 26 September 2000     

深度水解蛋白配方乳对早产儿喂养和生长影响的多中心临床对照研究

目的 通过多中心临床对照研究,观察深度水解蛋白配方乳（eHF）对早产儿喂养和生长的影响。方法 随机选取2012 年2 月至2013 年12 月入住国内8 家三甲医院的早产儿,根据喂养方案分组：（1）胎龄结果 纳入研究的早产儿共328 例。胎龄PPPP>0.05）。胎龄32~34 周的观察组发生喂养不耐受后用eHF,生后第2 周血清总胆红素水平低于其相应的对照组（PPP>0.05）。结论 eHF 可促进早产儿胃肠动力功能、加速胆红素代谢和排泄,且未增加EUGR 的发生。     

Apnoea of prematurity and arousal from sleep

The incidence of sudden infant death syndrome (SIDS) has been found to be consistently higher in preterm and low birth weight infants than in infants born at term and this increase is inversely related to gestational age. The incidence and severity of apnoea of prematurity, are also inversely related to gestational age. The aim of this study was to investigate whether a neonatal history of apnoea/bradycardia affected the maturation of arousal responses. Twenty-five premature infants were studied. A perinatal risk score was determined for each infant and infants were divided into those with a neonatal history of apnoea/bradycardia (n=16) and those without (n=9). All infants were studied using daytime polysomnography on three occasions: (a) a preterm study around 36 weeks gestation, (b) within 3 weeks of term, and (c) 2-3 months post-term. Multiple measurements of arousal threshold (cm H2O) in response to air-jet stimulation applied alternately to the nares were made in both active sleep (AS) and quiet sleep (QS). Arousal thresholds were elevated in apnoeic infants compared to control infants in both AS (P<0.05) and QS (P<0.001) at the term study and in QS at 2-3 months post-term (P<0.01). In addition, arousal thresholds were positively correlated with perinatal risk score in both sleep states, in all studies, with the exception of AS at 2-3 months when all infants were readily arouseable. We conclude that a history of prematurity with neonatal apnoea has a persisting effect on decreasing arousabilty from sleep and these infants may be at increased risk for SIDS.     

Safety of DTaP-based combined immunization in very-low-birth-weight premature infants: frequent but mostly benign cardiorespiratory events

OBJECTIVE: To evaluate the safety of diphtheria-tetanus-acellular pertussis-inactivated polio-Haemophilus influenzae type B (DTaP-IPV-HIB) immunization in premature infants. STUDY DESIGN: Observational study of 78 very low birth weight premature infants (mean gestational age, 28+/-2 weeks; mean birth weight, 1045+/-357 g) given DTaP-IPV-HIB vaccine before hospital discharge. Apnea, bradycardia, oxygen requirements and saturation, feeding practice, and medical interventions were assessed before and after immunization. The results were analyzed by the severity of the clinical condition and the persistence of prematurity-associated symptoms. RESULTS: Administration of DTaP-IPV-HIB elicited resurgence or increase in cardiorespiratory events in 47% of infants (15% had apnea, 21% had bradycardia, 42% of desaturations). Most vaccine-triggered events resolved spontaneously or after brief stimulation. The relative risk was 5- to 8-fold higher in infants with a severe clinical course or persistence of cardiorespiratory symptoms at the time of immunization. Bag-mask respiratory support was given to 5 of 78 infants, and O(2) requirements increased transiently in 4 of 21 infants with chronic lung disease, none requiring reventilation. Reintroduction of O(2) supplementation, interruption of active oral feeding, or postponing of hospital discharge was not required. CONCLUSIONS: Cardiorespiratory events were frequently increased after DTaP-IPV-HIB immunization, requiring monitoring and appropriate intervention. However, these episodes did not have detrimental impact on the infants' clinical course. Timely immunization is warranted even in the most vulnerable preterm infants.     

Clinical spectrum of neonatal apnoea in very low birthweight infants

This study quantifies apnoea and assesses the response to xanthine derivatives amongst 172 consecutively born, surviving very low birth weight (VLBW) infants, 136 appropriate weight for gestational age (AGA), 36 small for gestational age (SGA). All babies had electronic monitoring of heart and respiratory rates and nursing staff recorded episodes of apnoea (greater than 10 s), bradycardia (less than 100) and cyanosis. Only 42 (24.2%) babies had no episodes recorded. (25 AGA, 17 SGA). Sixty-four (37.2%) received active resuscitation on at least one occasion with six babies ventilated by bag and mask on more than 10 occasions. Apnoea had commenced by day 10 of life in all the babies who had apnoea and persisted beyond day 50 in only six; however four of these infants were still requiring active resuscitation. Apnoea had ceased by 37 weeks post-conceptual age in 88% and by 40 weeks in all but three babies. Risk factor analysis revealed a strong correlation (P less than 0.005) with lower gestational ages and birth weights, respiratory distress syndrome (RDS) and the problems associated with it, such as mechanical ventilation, patency of the ductus arteriosus (PDA) and chronic neonatal lung disease. A single, reversible cause for apnoea was rarely demonstrated. Care must be exercised with feeding, physiotherapy and suctioning the pharynx and trachea of 'at risk' infants. Xanthine derivatives were highly effective in decreasing the frequency of recurrent apnoea from a mean of 10.08 episodes one day before, to 1.83 two days after commencement of treatment.     

Agreement of invasive versus non‐invasive blood pressure in preterm neonates is not dependent on birth weight or gestational age

Purpose: Blood pressure constitutes an important parameter in the assessment of the cardiovascular status in preterm infants. Invasive arterial blood pressure (IBP) is considered the ‘gold‐standard’, but non‐invasive blood pressure (NIBP) is used frequently in preterm infants. The aim of this prospective study was to compare mean IBP and mean NIBP arterial blood pressure measurements in three subsets of preterm infants (>1500 g; 1000–1500 g, and <1000 g, and >31 weeks, 28–31 weeks, and <28 weeks of gestation). Methods: Prospective, simultaneous assessment of both IBP and NIBP measurements in 50 preterm neonates at 6, 12, 18, 24 h after birth in a tertiary University centre. Results: Mean gestational age was 26.7 ± 2.2 (24–32) in group I (n= 18), 29.6 ± 2.0 (27–34) in group II (n= 19) and 32.2 ± 1.9(30–36) weeks in group III (n= 13), respectively; mean birth weight was 777 ± 161 (495–995), 1251 ± 154 (1010–1490) and 2010 ± 332 (1590–2550) g. Mean IBP and mean NIBP increased significantly during the first 24 h of life in all three sub‐groups (P < 0.01); IBP and NIBP measurements were significantly correlated, and showed good agreement, irrespective of birth weight and gestational age. Conclusions: Although IBP monitoring is considered the ‘gold standard’, NIBP values showed good agreement with those obtained invasively irrespective of gestational age and birth weight. We conclude that NIBP monitoring constitutes an important parameter in the assessment of the cardiovascular status even in extremely low birth weight infants.     

Association between early parenteral nutrition and the development of bronchopulmonary dysplasia in preterm infants北大核心CSCD

目的分析生后1周未能肠内营养的胎龄<32周早产儿肠外营养素摄入情况与支气管肺发育不良(bronchopulmonary dysplasia,BPD)发生的关系。方法回顾性收集2017年10月—2022年8月出生并于生后24 h内转入苏州大学附属儿童医院新生儿重症监护病房、胎龄<32周、生后第1周营养摄入完全依靠肠外营养的早产儿作为研究对象,包括79例BPD患儿和73例非BPD患儿。比较两组早产儿住院期间的临床资料。结果BPD组生后体重下降超过10%、宫外生长发育迟缓、胃肠外营养相关性胆汁淤积的患儿比例较非BPD组高(P<0.05),出生体重恢复时间、达完全肠内营养时间、出院时纠正胎龄均大于非BPD组(P<0.05),而纠正胎龄36周时体格发育Z评分低于非BPD组(P<0.05)。BPD组生后1周内液体摄入量高于非BPD组(P<0.05),而热卡摄入量低于非BPD组(P<0.05);BPD组生后1周内氨基酸、葡萄糖、脂质的起始剂量及其摄入总量均低于非BPD组(P<0.05);BPD组生后第3天的糖脂比高于非BPD组,生后第7天的热氮比和糖脂比均高于非BPD组(P<0.05)。结论BPD患儿生后1周内氨基酸和脂质的摄入量及其所提供的热卡占总热量的比例低于非BPD患儿,提示早期肠外营养素摄入与BPD的发生可能有关。     

不同胎龄早产儿生后24 h内血小板及相关参数参考范围

目的 研究不同胎龄早产儿生后24 h内血小板及相关参数参考范围并探讨其临床意义。方法 根据纳入标准和排除标准,收集2018年1~12月入住新生儿重症监护室且出生胎龄为23~36⁺⁶周早产儿1 070例的临床资料进行回顾性分析,观察生后24 h内不同胎龄早产儿血小板参数参考范围。结果 不同胎龄早产儿血小板计数（PLT）及血小板压积（PCT）水平比较差异无统计学意义（P > 0.05）;晚期早产儿组（34~36⁺⁶周,n=667）血小板平均体积（MPV）及血小板体积分布宽度（PDW）均低于极早早产儿组（23~27⁺⁶周,n=36）和早期早产儿组（28~33⁺⁶周,n=367）（P < 0.05）。不同性别早产儿之间血小板及相关参数比较差异均无统计学意义（P > 0.05）。按照不同胎龄来计算早产儿血小板参数的参考范围,23~36⁺⁶周早产儿PLT参考范围为（92~376）×10⁹/L,PCT参考范围为0.1%~0.394%;23~33⁺⁶周早产儿MPV参考范围为9.208~12.172 fl,PDW参考范围为8.390%~16.407%;34~36⁺⁶周早产儿MPV参考范围为9.190~11.950 fl,PDW参考范围为9.046%~15.116%。结论 不同胎龄早产儿生后24 h内MPV及PDW不同,依据胎龄制定早产儿MPV及PDW参考范围更有助于指导临床工作。     

Cardiorespiratory development in extremely preterm infants: vulnerability to infection and persistence of events beyond term-equivalent age

OBJECTIVE: Apnoea, bradycardia and hypoxemia occur frequently in extremely preterm infants, yet there is little longitudinal data describing cardiorespiratory development in these infants. This prospective study characterized early age-dependent changes in cardiorespiratory function and determined how activity is affected by factors such as underlying disease, postnatal insults and therapeutic interventions. PATIENTS AND METHODS: Thirty-three infants born between 23 and 28 weeks gestational age (GA) were monitored weekly from birth to beyond term-equivalent age (i.e. 25-45 weeks postconceptional age, PCA). Baseline cardiorespiratory activity as well as apnoea/hypopnoea, bradycardia and hypoxemia events were examined using impedance pneumography, electrocardiography (ECG) and pulse oximetry, respectively. RESULTS: Three hundred thirty-eight cardiorespiratory recordings lasting 3236 h were analysed. While the respiratory rate (RR) did not change during the early postnatal period, heart rate (HR) decreased and O2 saturation improved. There were 5973 total cardiorespiratory events, and their incidence decreased with advancing age. However, they still occurred frequently at term-equivalent age and after hospital discharge (mean PCA at discharge=38.3+/-0.5 weeks). Moreover, infection significantly increased apnoea/hypopnoea and hypoxemia incidence. CONCLUSION: The persistence of cardiorespiratory events beyond term-equivalent age as well as the marked impact of infection on cardiorespiratory function indicate that close surveillance after hospitalization is of crucial importance in extremely preterm infants.     

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     

胎龄≤32周早产儿低血糖的危险因素分析

目的 探讨胎龄≤32周早产儿出生后发生低血糖的危险因素。方法 回顾性纳入2017年1月至2020年6月入住新生儿重症监护病房的86例胎龄≤32周低血糖早产儿作为低血糖组,随机选取同期住院监测血糖正常的早产儿172例为对照组。采用单因素分析与多因素logistic回归分析筛选早产儿低血糖的危险因素。结果 研究期间早产儿共计515例,其中低血糖86例（16.7%）。低血糖组小于胎龄儿（SGA）、剖宫产出生、孕母高血压、产前使用激素的比例均高于对照组（P < 0.05）,而出生体重及血糖检测前已静脉使用葡萄糖的比例均低于对照组（P < 0.05）。SGA（OR=4.311,95% CI：1.285~14.462）、孕母高血压（OR=2.469,95% CI：1.310~4.652）和产前使用激素（OR=6.337,95% CI：1.430~28.095）为早产儿低血糖的危险因素（P < 0.05）,静脉使用葡萄糖（OR=0.318,95% CI：0.171~0.591）为早产儿低血糖的保护因素（P < 0.05）。结论 SGA、孕母高血压和产前使用激素可增加胎龄≤32周早产儿早期发生低血糖的风险;对胎龄≤32周早产儿,建议生后尽早静脉使用葡萄糖,以减少低血糖的发生。     

Lung volume measurements in infants with and without chronic lung disease

Infants born prematurely who develop chronic lung disease (CLD) have airways obstruction and hence may have low lung volume. The aim of this study was to test that hypothesis and ascertain whether the nature of the comparison control group influenced the results. Sixteen infants who were oxygen dependent for more than 28 days (CLD) and eight infants without CLD had measurements of functional residual capacity (FRC) at 14 and 28 days. The 16 CLD infants consisted of eight less than 27 weeks gestational age (group A) and eight greater than 26 weeks gestational age (group B). The eight infants without CLD (group C) were each matched for gestational age and gender to infants in group B. Group A compared to group C had lower FRCs both at 14 days (median 18 ml/kg vs 27 ml/kg, P<0.01) and 28 days (median 20 ml/kg vs 26 ml/kg, P<0.05), but group A differed from group C with respect to both gestational age (P<0.01) and birth weight (P<0.01). The FRC results of group B were lower than those of their matched controls (group C) only at 28 days (median 22 vs 26 ml/kg, P<0.05). Overall, the FRC results at 14 and 28 days correlated significantly with the duration of oxygen and ventilator dependence and weakly with gestational age. Conclusion These results support the hypothesis that FRC results are lower in infants with CLD compared to those without CLD when measured in the neonatal period and emphasize the importance of an appropriate control group. Measurement of lung volume may facilitate assessment of the response to therapies for CLD. Received: 5 May 1997 / Accepted in revised form: 29 September 1997     

Dexamethasone and hypertension in preterm infants

The magnitude and duration of the effect of dexamethasone on systolic blood pressure has been examined in 13 very preterm infants (median gestational age 25 weeks). All had chronic lung disease (CLD). To exclude any effect of CLD on blood pressure each infant acted as his or her own control. Systolic blood pressure increased in all infants (P<0.01) and remained elevated for at least 48h following cessation of therapy. The median maximum increase in blood pressure was 24 mm Hg (range 13–49 mmHg) and occurred on day 4 (median, range 2–10) of treatment. One infant developed hypertensive encephalopathy. These results demonstrate the need to monitor infants with CLD throughout steroid therapy and preferably for some days after it has ceased.     

极早产儿存活率和并发症的多中心回顾性研究

目的 研究极早产儿存活率和严重并发症发生情况,并分析其影响因素。 方法 回顾性收集2018年1月至2019年12月江苏省11家医院新生儿科收治的极早产儿（胎龄<32周）的一般资料,分析其存活率和严重并发症发生情况,采用多因素logistic回归分析评估极早产儿死亡和严重并发症发生的危险因素。 结果 共纳入极早产儿2 339例,其中存活2 010例（85.93%）,无严重并发症存活1 507例（64.43%）。胎龄22~25⁺⁶周、26~26⁺⁶周、27~27⁺⁶周、28~28⁺⁶周、29~29⁺⁶周、30~30⁺⁶周、31~31⁺⁶周各组极早产儿存活率分别是32.5%、60.6%、68.0%、82.9%、90.1%、92.3%、94.8%,随着胎龄增加,存活率呈升高趋势（P<0.05）;相同胎龄分组下无严重并发症存活率分别是7.5%、18.1%、34.5%、52.2%、66.7%、75.7%、81.8%,随着胎龄增加,无严重并发症存活率呈升高趋势（P<0.05）。多因素logistic回归分析显示,胎龄大、出生体重大、母亲产前使用糖皮质激素是极早产儿死亡的保护因素（P<0.05）,而1 min Apgar评分≤3分是极早产儿死亡的危险因素（P<0.05）;胎龄大、出生体重大是存活极早产儿发生严重并发症的保护因素（P<0.05）,而5 min Apgar评分≤3分、母亲绒毛膜羊膜炎是存活极早产儿发生严重并发症的危险因素（P<0.05）。 结论 极早产儿存活率与胎龄密切相关。1 min Apgar评分≤3分可增加极早产儿死亡的风险,而胎龄大、出生体重大、母亲产前使用糖皮质激素与死亡风险降低有关。5 min Apgar评分≤3分和母亲绒毛膜羊膜炎可增加极早产儿严重并发症发生的风险,而胎龄大、出生体重大可降低严重并发症发生的风险。