Reactivity of skin blood flow and heart rate to thermal stimulation in infants during the first postnatal days and after a two-month follow-up

The reactivity of skin blood flow and heart rate to periodic thermal stimulation was studied in 10 term small-for-gestational age (SGA) infants, in 9 preterm and 8 term normal-sized infants during the first two postnatal months. During the first postnatal days, the increase in thermally stimulated skin blood flow oscillations was absent in SGA infants but was clearly present in both preterm ( p < 0.01) and term ( p <0.01) normal-sized infants. The responsiveness of SGA infants improved during the follow-up ( p < 0.05). The response of the periodic heart rate variability of SGA and preterm infants was inferior to term normal-sized infants until the age of 2 months. The cardiovascular responsiveness of growth-retarded infants seems abnormal during the first days of life, and may impair their ability to meet stress, e.g. changes of ambient temperature.     

Reactivity of skin blood flow and heart rate to external thermal stimulation in anencephaly

Oscillations of skin blood flow and heart rate can be synchronised using external rhythmic thermal stimulation in healthy adults and infants. We examined the effect of thermal stimulation on the cutaneous circulation and heart rate of an anencephalic neonate using cutaneous laser Doppler flowmetry and ECG monitoring. The results suggest that synchronisation of SBF and HR to thermal stimulation can also be induced in an anencephalic newborn.     

新生儿黄疸光疗时氧自由基对光疗致溶血的影响

目的探讨新生儿黄疸光疗时氧自由基变化对光疗致溶血的影响。方法将高胆光疗病人随机分为维生素E干预组和对照组，动态测定红细胞超氧化物歧化酶（R - SOD）、血浆总超氧化物歧化酶（T - SOD）、铜锌超氧化物歧化酶（CuZn - SOD）、丙二醛（MDA）、活性氧（ROS）、总胆红素（TB）、血红蛋白（HB）及光疗指数，与正常新生儿组测定值比较。结果各组30例，光疗前：干预组与对照组各项指标差异无显著性，P 〉 0．05；干预组、对照组比正常组MDA高、R - SOD低，差异有显著性，P 〈 0.01或0.05。HB三组无显著性差异。光疗时对照组R - SOD、HB降低，ROS、MDA增高，干预组R - SOD增高，ROS、MDA及HB降低；在光疗24、36、48h时，干预组比对照组，R - SOD、HB高，MDA、ROS低、光疗指数小，P 〈 0．01或P 〈 0．05。干预组和对照组光疗后HB均比光疗前低，差异有显著性，P 〈 0．01。结论光疗时红细胞抗氧化能力进一步下降，氧自由基生成增多导致红细胞脂质过氧化损害加重、溶血加剧是光疗致溶血重要机制之一。维生素E干预可抗光疗时氧自由基损害、减轻溶血和缩小光疗指数。     

新生儿黄疸光疗时氧自由基对光疗致溶血的影响

目的探讨新生儿黄疸光疗时氧自由基变化对光疗致溶血的影响。方法将高胆光疗病人随机分为维生素E干预组和对照组,动态测定红细胞超氧化物歧化酶(R-SOD)、血浆总超氧化物歧化酶(T-SOD)、铜锌超氧化物歧化酶(CuZn-SOD)、丙二醛(MDA)、活性氧(ROS)、总胆红素(TB)、血红蛋白(HB)及光疗指数,与正常新生儿组测定值比较。结果各组30例,光疗前:干预组与对照组各项指标差异无显著性,P>0·05;干预组、对照组比正常组MDA高、R-SOD低,差异有显著性,P<0·01或0·05。HB三组无显著性差异。光疗时对照组R-SOD、HB降低,ROS、MDA增高,干预组R-SOD增高,ROS、MDA及HB降低;在光疗24、36、48h时,干预组比对照组,R-SOD、HB高,MDA、ROS低、光疗指数小,P<0·01或P<0·05。干预组和对照组光疗后HB均比光疗前低,差异有显著性,P<0·01。结论光疗时红细胞抗氧化能力进一步下降,氧自由基生成增多导致红细胞脂质过氧化损害加重、溶血加剧是光疗致溶血重要机制之一。维生素E干预可抗光疗时氧自由基损害、减轻溶血和缩小光疗指数。     

Haemodynamic consequences of phototherapy in term infants

The effect of blue-light phototherapy on cardiac output and brain and kidney perfusion was studied in 12 term infants with pulsed Doppler ultrasound. Mean (±SD) gestational age and birth weight were 39.0 (±1.6) weeks and 3438 (±533) g respectively. Mean (±SD) age of the infants at which phototherapy was initiated was 3.5 (±0.8) days. Left ventricular output (LVO), mean left pulmonary artery blood flow (LPA), mean blood flow velocities of the internal carotid (CBFV) and renal (RBFV) arteries were studied in all infants prior to the onset of phototherapy, 30 min, 2 h, and 12 h after initiation of phototherapy, and before and 12–24 h after discontinuation of phototherapy. LVO decreased immediately after the onset of phototherapy. However, after 12 h, LVO returned to pre-phototherapy values. LPA increased significantly after 12 h of exposure. LPA returned to pre-phototherapy values after discontinuation of phototherapy. CBFV increased, whereas RBFV decreased significantly after 2 h of exposure. After discontinuation of phototherapy CBFV as well as RBFV values returned to pre-phototherapy values. Conclusion Phototherapy does affect cardiac output and organ blood flow velocity in term infants. After termination of phototherapy the effect of phototherapy disappears. Received: 14 August 1997 / Accepted in revised form: 17 May 1998     

Uniform national guidelines do not prevent wide variations in the clinical application of phototherapy for neonatal jaundice

Aim

This study compared the use of phototherapy for neonatal jaundice in all 21 Norwegian neonatal intensive care units (NICUs) from 2013‐2014 to improve practice.

Methods

Information on all types of phototherapy devices was collected, and irradiance was measured from random units at 20 cm and 50 cm from the light source. We gathered information on local practice rules, including the use of single, double or triple phototherapy, how infants were positioned, the frequency of blood sampling, rules for using reflective surfaces and interrupting phototherapy. In every NICU, we asked one nurse with more than five years of experience and one with less than one year to set up phototherapy equipment, then measured the irradiance and distance.

Results

Photodiodes were the most common of the eight types of phototherapy devices used. Rules for the distance from the device to the infant varied from 10 to 40 cm and in practice they varied from 15 to 48 cm, with irradiance ranging from 11.1–56.1 W/m². There were significant variations between NICUs with regard to the overall treatment duration and duration in most birthweight categories.

Conclusion

There were considerable variations in phototherapy practices among Norwegian NICUs. In particular, the significant variations in duration need to be addressed.     

Do spectral bands of fetal heart rate variability associate with concomitant fetal scalp pH?

Background

Objective information on specific fetal heart rate (FHR) parameters would be advantageous when assessing fetal responses to hypoxia. Small, visually undetectable changes in FHR variability can be quantified by power spectral analysis of FHR variability.

Aims

To investigate the effect of intrapartum hypoxia and acidemia on spectral powers of FHR variability.

Study design

This is a retrospective observational clinical study with data from an EU multicenter project.

Subjects

We had 462 fetuses with a normal pH-value (pH > 7.20; controls) in fetal scalp blood sample (FBS) and 81 fetuses with a low scalp pH-value (≤ 7.20; low-FBS pH-fetuses). The low-FBS pH-fetuses were further divided into two subgroups according to the degree of acidemia: fetuses with FBS pH 7.11–7.20 (n = 58) and fetuses with FBS pH ≤ 7.10 (n = 23).

Outcome measures

Spectral powers of FHR variability in relation to the concomitant FBS pH-value.

Results

Fetuses with FBS pH ≤ 7.20 had increased spectral powers of FHR variability compared with controls (2.49 AU vs. 2.23 AU; p = 0.038). However, the subgroup of most affected fetuses (those with FBS pH ≤ 7.10) had significantly lower FHR variability spectral powers when compared to fetuses with FBS pH 7.11–7.20.

Conclusions

This study shows that spectral powers of FHR variability change as a fetus becomes hypoxic, and that spectral powers decrease with deepening fetal acidemia.     

Patent ductus arteriosus in preterm infants is associated with cardiac autonomic alteration and predominant parasympathetic stimulation

Background

Hemodynamic disorders in patent ductus arteriosus (PDA) may alter the stimulation of the autonomic nervous system.

Aim

The objective of this study was to analyze the orthosympathetic–parasympathetic balance in preterm infants with PDA.

Study design and subjects

Patients were included from consecutive admissions to Amiens University Hospital from 2009 to 2011. We defined a PDA group and a Control group (echographic criteria). For each patient, three 4-minutes segments of ECG were recorded during quiet sleep and the RR chronologic series were extracted, and spectral (Fourier Transform) and time-domain analyses were performed. For each parameter of heart rate variability (HRV), average of three measures was determined and analysed.

Results

Forty-four patients were included for analysis. The total HRV power, LF/HF ratio and SDNN were lower in the PDA group (n = 22, gestational age 28.2 w ± 1.9) than in the Control group (n = 22, gestational age 28.8 w ± 2). The decrease in LF power destabilized the autonomic balance in favour of parasympathetic stimulation. After adjustment for postconceptional age, PDA was still associated with parameters of autonomic neural stimulation.

Conclusion

These results suggest association of PDA with predominance of parasympathetic stimulation in preterm infants. The mechanisms of homeostasis in patients with PDA are very complex and involve both circulatory adaptations and control by autonomic pathway. If confirmed, our results could be interesting for future researches aiming to verify the interest of new targeted therapies for the management of PDA.     

Autonomic organization of respirocardial function in healthy human neonates in quiet and active sleep

BACKGROUND AND AIM: It is not known on which time scales the nonlinear respirocardial interactions occur. This work's aim is to quantitatively assess functional respirocardial organization during quiet and active sleep of healthy full-term neonates by autonomic information flow (AIF) without limitation on specific time scales. Representing respirocardial interactions on a global time scale AIF carries information on a wider scope of interdependencies than known linear and nonlinear measures described. It assesses the complexity of heart rate fluctuations (HRF) and respiratory movements (RM) and their interaction comprising both linear and nonlinear properties. Thus, we hypothesized AIF to characterize novel aspects of sleep state-dependent respirocardial interaction. METHODS: RM and ECG-derived HRF of six healthy full-term neonates were studied. We analyzed their power spectra, coherence, auto- and cross-correlation and complexity estimated on local ("next sample" prediction) and global time scales (an integral over AIF predicting for all time lags in HRF and RM). RESULTS: We found the global AIF of HRF and RM to differ significantly between active and quiet sleep in all neonates, whereas on a local time scale this applied to the HRF AIF only. HRF complexity was larger in quiet than in active sleep. Respirocardial interaction was less complex in quiet versus active sleep in the high frequency band only. CONCLUSION: Complex sleep state-related changes of respirocardial interdependencies cannot be identified completely on the local time scale. Considering the global time scale of respirocardial interactions allows a more complete physiological interpretation with regard to the underlying autonomic dynamics.     

选择性头部亚低温治疗对新生儿缺氧缺血性脑损伤脑血流动力学的影响

目的探讨选择性头部亚低温治疗新生儿缺氧缺血性脑损伤(hypoxic-ischemic braindamage,HIBD)期间脑血流动力学的变化。方法38例中重度HIBD新生儿随机分为常温组(20例)和低温组(18例)。生后6 h内开始治疗,常温组维持体温在36℃;低温组维持鼻咽温度在34℃,持续72h,然后自然复温。其他治疗方法两组相同。7例无窒息史及呼吸系统疾病的新生儿作为对照组。三组均持续观察84 h,分别在生后6、12、24、48、72和84 h采用经颅多普勒血流诊断仪测定大脑中动脉血流速率。结果常温组HIBD新生儿生后6h收缩期峰流速率(Vs)为(32.42±5.28)cm/s、舒张末期血流速率(Vd)为(14.28±7.54)cm/s、平均血流速率(Vm)为(20.42±2.76)cm/s,明显低于对照组[分别为(24.05±6.87)(、7.27±5.06)和(15.15±5.55)cm/s](P均<0.05);阻力指数(RI)0.81±0.15,较对照组(0.67±0.09)明显增加,(P<0.05)。生后12 h,Vs和Vm与对照组无差异,但RI(0.72±0.12)较对照组(0.62±0.08)仍显著升高(P<0.05)。生后24、48 h,Vs[(28.0±7.28)(、32.0±6.29)cm/s]和Vm[(17.55±5.28)、(18.65±4.61)cm/s]较对照组显著降低(P<0.05)。生后72和84 h两组各指标无统计学差异。亚低温治疗后大脑中动脉Vs和Vm在生后12和48 h较常温组增加(P<0.05),RI降低(P<0.05),且与对照组无差别。结论中重度新生儿HIBD脑血流速率明显降低,选择性头部亚低温治疗新生儿HIBD可以改善脑血流动力学。     

Postural differences in cardiac dynamics during quiet and active sleep in low birthweight infants

To study the effects of body position (supine versus prone) on changes in cardiac inter-beat interval during quiet and active sleep, 6-h continuous electrocardiographic recordings and simultaneous minute-by-minute behavioural activity state assignments were made in 61 healthy, growing, low birthweight infants. The infants weighed 795-1600 g at birth and ranged between 30-38 wk in postconceptual age. Infants were randomly assigned to the supine or prone position for the first 3 h of each study; the position was reversed for the second 3 h. Higher heart rates and lower time and frequency domain measures of inter-beat interval variability were observed in the prone position as compared to the supine position, during both quiet and active sleep. In addition, an analysis of consecutive increases and decreases in the instantaneous heart rate revealed a lower incidence of sustained accelerations or decelerations in the prone position. Although consistent findings concerning inter-beat interval variability and sleeping position were obtained from all analytic techniques, the differences derived from analysis of consecutive inter-beat changes were the most robust. These differences in multiple measures of cardiac rate and rhythm between prone and supine positions suggest that autonomic control of the heart is altered by body position, the net effect on heart rate being increased sympathetic dominance.     

Autoregressive analysis of cardiac RR intervals in preterm and full-term infants

For the purpose of obtaining information on the maturation process of the autonomic nervous system in pre- and full-term infants, polygraphs were recorded during sleep from a total of 52 appropriate-for-dates infants at a conceptional age of 28–41 weeks. The 104 RR interval time series was calculated by auto-regressive (AR) and component analysis. Histograms of damping frequencies obtained were divided into two frequency bands: low frequency fluctuations (LF) of less the 0.1 cycle/beat (c/b) and high frequency fluctuations (HF) of more than 0.15 c/b. Total power and LF power decreased with increases in the conceptional age or postnatal age at a significance level of 0.01, respectively. In addition, the HF amount of bio-informing activity increased (P< 0.001) and the damping time of HF also increased (P <0.01). From these results, it was speculated that the activity of the sympathetic system decreases with increases in conceptional or postnatal age. It was also speculated that increased regularity and oscillatory duration in HF might be caused by the development of the reciprocal response of respiration to heart rate variation.     

窒息新生儿心率变异性的临床研究

目的 探讨窒息新生儿心率变异性(heart rate variability,HRV)与心肌损害的相关性.方法 对53例窒息新生儿与40例健康新生儿进行24h全程动态心电图记录,对24h窦性心律进行HRV时域分析,时域分析指标包括:正常窦性R-R间期的标准差(SDNN);全程记录中每5分钟R-R间期平均值的标准差(SDANN);全程记录中每5分钟R-R间期标准差的平均值(SDNNindex);相邻R-R间期差值的均方根值(rMSSD);正常R-R间期标准差＞50 ms的百分比(PNN50).结果 (1)窒息新生儿与正常对照新生儿24h最快心率、最慢心率、平均心率比较,差异均有统计学意义(P＜0.05);轻、重度窒息新生儿间以上指标比较差异也有统计学意义(P＜0.05);重度窒息3种心率指标明显降低.(2) HRV时域分析中,轻、重度窒息新生儿SDNN、SDANN与正常对照新生儿比较差异有统计学意义(P＜0.05),轻、重度窒息SDNN、SDANN、SDNNindex、rMSSD及PNN50 5项指标组间比较差异无统计学意义(P＞0.05).SDNNindex、rMSSD及PNN503组间未见明显差异.结论 新生儿窒息心肌损害会导致心脏自主神经功能受损并影响心率的变化,受损程度与窒息缺氧严重程度有关.     

Skin‐to‐skin care in neonatal intensive care units in the Nordic countries: a survey of attitudes and practices

Aim: To investigate the application of skin‐to‐skin care (SSC) in the Nordic countries, the existence of guidelines for SSC and the attitudes of neonatal staff towards SSC. Methods: One questionnaire was distributed at unit level and one at staff level in all Nordic neonatal intensive care units (n = 109). Results: The unit questionnaire was answered by 95 (87%) units and the staff questionnaire by 1446 staff members (72%). All units offered SSC to various degrees, but guidelines only existed at 47% of them. Units in Denmark, Norway and Sweden seemed to use SSC earlier, longer and in more medically complicated situations than units in Finland and Iceland. Seventy‐seven per cent of the units had private rooms where parents and infants could stay together, still the physical environment of the units limited the use of SSC. Medical risks were considered the main barrier for further implementation of SSC, while general development and early interaction were the most frequently mentioned benefits. Conclusion: Skin‐to‐skin care is implemented in all Nordic neonatal units, but offered to various degrees, to various populations and to varying extents. Danish, Norwegian and Swedish units are offering SSC more extensively than units in Finland and Iceland.     

Power spectrum analysis of fetal heart rate variability at near term and post term gestation during active sleep and quiet sleep

Background

Spectral analysis of fetal heart rate variability is promising for assessing fetal condition. Before using spectral analysis for fetal monitoring it has to be determined whether there should be a correction for gestational age or behavioural state.

Aims

Compare spectral values of heart rate variability between near term and post term fetuses during active and quiet sleep.

Study design

Case-control. Cases had a gestational age of ≥ 42 weeks; controls were 36 to 37 weeks. Fetuses were matched for birth weight percentile.

Subjects

STAN^® registrations from healthy fetuses. For each fetus one 5-minute segment was selected during active and one during quiet sleep.

Outcome measures

Absolute and normalized low (0.04-0.15 Hz) and high frequency power (0.4-1.5 Hz) of heart rate variability.

Results

Twenty fetuses were included. No significant differences were found between cases and controls in absolute (481 and 429 respectively, P = 0.88) or normalized low (0.78 and 0.80 respectively, P = 0.50) or absolute (41 and 21 respectively, P = 0.23) or normalized high frequency power (0.08 and 0.07 respectively, P = 0.20) during active state. During rest, normalized low frequency power was lower (0.58 and 0.69 respectively, P = 0.03) and absolute (16 and 10 respectively, P = 0.04) and normalized high frequency power were higher (0.21 and 0.14 respectively, P = 0.01) in cases compared to controls. Absolute and normalized low frequency power were higher during active state compared to rest in both groups (all P values < 0.05).

Conclusions

We found sympathetic predominance during active state in fetuses around term. Post term parasympathetic modulation during rest was increased compared to near term.     

Specific change in spectral power of fetal heart rate variability related to fetal acidemia during labor: comparison between preterm and term fetuses

Background

Spectral analysis of fetal heart rate (FHR) variability is a useful method to assess fetal condition. There have been several studies involving the change in spectral power related to fetal acidemia, but the results have been inconsistent.

Aims

To determine the change in spectral power related to fetal umbilical arterial pH at birth, dividing cases into preterm (31–36 weeks) and term (≥ 37 weeks) gestations.

Study design

Case–control study. The 514 cases of deliveries were divided into a low-pH group (an umbilical arterial pH < 7.2) and a control group (pH ≥ 7.2).

Subjects

FHR recorded on cardiotocography during the last 2 h of labor.

Outcome measures

The spectral powers in various bands of FHR variability.

Results

In preterm fetuses, the total, low (LF), and movement (MF) frequency spectral powers and LF/HF ratio were significantly lower in the low-pH group than the control group (all P < 0.05). In contrast, in term fetuses, the total frequency, LF, and MF powers were significantly higher in the low-pH group than the control group (all P < 0.05). The area under the receiver operating characteristic of LF power to detect a low pH at birth was 0.794 in preterm fetuses and 0.595 in term fetuses. The specificity was 86.8% and 93.3% in preterm and term fetuses, respectively.

Conclusions

The changes in spectral power responding to a low pH are different between term and preterm fetuses. Spectral analysis of FHR variability may be useful fetal monitoring for early detection of fetal acidemia.     

北京地区3至12岁1581例健康儿童心率变异性分析

目的 探讨健康儿童早搏、房室传导阻滞、心率变异性（heart rate variability,HRv）与年龄、性别的关系.方法 1581例健康儿童分为3～6岁、～10岁、～12岁3组,按年龄、性别及室性早搏发生与否分组进行心律失常发生率、HRV的5项时域值的比较.结果 （1） ECG和24h心电监测（Holter）示健康儿童的平均心率、最慢心率和最快心率随年龄增加而降低,PR、QTc间期相反,除PR间期外其余各项指标差异均有统计学意义（P＜0.01）.（2）健康儿童Holter和ECG心律失常阳性检出率差异有统计学意义（x2 =4.810,P＜0.05）.（3）不同年龄组室上性早搏、室性早搏、Ⅰ.房室传导阻滞的发生率差异有统计学意义（P＜0.05）,且随年龄增长有升高或下降趋势;与3～6岁组比较,～ 10岁和～12岁组室性早搏发生危险度明显增加（OR =1.31和2.04）.（4） HRV的5项时域指标值随年龄增长而增高,各年龄组比较差异有统计学意义（P＜0.01）.（5） HRV的5项时域指标值男性均高于女性（P＜0.01）.（6）按室性期前收缩分组,HRV的5项时域指标差异均无统计学意义（P＞0.05）.结论 （1）健康儿童的心率随年龄增长逐渐下降,QTc间期随年龄增加而延长.（2）健康儿童Holter检测心律失常中室上性早搏的发生率最高.（3）健康儿童中室上性早搏、室性早搏的发生随年龄增长而增多,青春前期更明显.Ⅰ°房室传导阻滞的发生随年龄的增长有下降趋势.上述类型心律失常的发生与性别无关.（4）健康儿童HRV存在年龄差异,提示儿童心脏自主神经系统发育尚不成熟.（5）青春期前,男女间HRV的差异最为显著,提示可能此年龄段男女间心脏自主神经发育的不一致性.（6）健康儿童室性早搏的发生大部分为良性早搏.     

北京地区3~12岁920名儿童心率变异性分层随机抽样调查分析

摘要 目的 测定920名3～12岁儿童心率变异性（HRV）时域指标值范围；明确HRV与年龄、性别的相关性；研究无症状期前收缩和QT延长儿童HRV的变化。方法 920名3～12岁儿童分为学龄前期组（3～6岁，274名)、学龄期组（～10岁，365名)、青春前期组（～12岁，281名)，行24 h HRV时域分析；进行各年龄组、性别HRV的方差分析；室性期前收缩按照Lown分级法分成4组，QT延长以QTc>450 ms为界分成正常和延长2组，分别进行组间HRV的方差分析。结果 ①HRV各时域指标值随年龄增长而增高，各年龄组均数间差异有统计学意义（P<0.01）。②按性别分组比较HRV 5项时域指标值，男性高于女性，总体标准差（SDNN）、均值标准差（SDANN）和标准差均值（SDNNINX）3项指标均数差异有统计学意义（P<0.05），学龄期和青春前期组SDNN、SDANN均数的男、女间差异有统计学意义（P<0.01），差值均方的平方根（RMSSD）和差值>50 ms的百分比（PNN50）均数差异无统计学意义（P>0.05）。③无期前收缩组与无症状偶发期前收缩组、频发期前收缩组和病理性期前收缩组HRV时域指标值差异无统计学意义（P>0.05）。④QT间期正常组和延长组HRV时域指标值差异无统计学意义（P>0.05）。结论 ①儿童HRV存在年龄差异。HRV的时域指标值随年龄增长而增加，提示儿童心脏自主神经系统发育尚不成熟，交感神经和迷走神经随年龄的增长发育渐趋完善和平衡。②学龄前期至青春前期，HRV男性高于女性。提示心脏自主神经总张力男性高于女性，男性心交感神经张力较女性相对增高；而心迷走神经张力男、女间差异无统计学意义，男、女心脏迷走神经功能发育可能较一致。青春期前，男、女间HRV的差异最为显著。可能提示此年龄段男、女间心脏自主神经发育的不一致性。③无症状期前收缩及QT间期延长儿童的HRV与其他儿童HRV相比无明显变化。