Assessing patent ductus arteriosus in preterm infants from standard neonatal intensive care monitoring.

Monitoring patent ductus arteriosus (PDA) in premature infants is currently performed intermittently using echocardiography which requires considerable expertise. The aim of this pilot study was to investigate whether PDA status could be assessed from standard neonatal intensive care monitoring. Electrocardiography (ECG) and blood pressure (BP) waveforms were acquired from extremely preterm infants using standard neonatal monitors. We developed software using MATLAB to analyse ECG and BP waveforms and their interrelationships in terms of pulse transit time (PTT) and pulse wave velocity (PWV). The times from peak systolic BP to diastolic trough (BPFt) and from the diastolic trough to peak systolic BP (BPRt) were also calculated. PTT, BPFt and BPRt were normalised for heart rate (HR) termed NPTT, NBPFt and NBPRt, respectively. ECG, invasive aortic BP monitoring and echocardiography were performed in 14 preterm infants < 29 weeks' gestation in the first 3 days after birth. The median (range) birth weight of the infants was 0.90 (0.48-1.31) kg, gestation 26.6 (24.0-28.7) weeks, PDA diameter 1.6 (0.8-3.6) mm and mean BP 32 (16-40) mmHg. We found a significant positive correlation between PDA diameter and NPTT (r = 0.69, P = 0.007) as well as NBPFt (r = 0.65, P = 0.012) and NBPRt (r = 0.71, P = 0.005). No relationship was found between PDA diameter and pulse pressure.Conclusions: Interrelationships between ECG and BP traces as well as BP waveform time analysis are straightforward to measure and associated with PDA diameter. The results of this pilot study suggest that this approach may help provide biomarkers for continuous monitoring PDA diameter and function. What is Known: • Patent ductus arteriosus (PDA) in premature infants is associated with increased risk of developing chronic lung disease, necrotising enterocolitis and cerebral injury. • Currently PDA is assessed intermittently using echocardiography which requires considerable expertise and sometimes is not well tolerated by critically ill preterm infants. What is New: • Blood pressure (BP) and ECG waveform interrelation and BP trace time analysis, taking account of heart rate, relate to PDA diameter. • ECG and BP waveform phase difference as well as BP waveform time analysis may be useful in the continuous assessment of PDA function.

Comparison of cerebral tissue oxygenation values in full term and preterm newborns by the simultaneous use of two near-infrared spectroscopy devices: an absolute and a relative trending oximeter.

The aim of this study is to compare a two-wavelength light emitting diode-based tissue oximeter (INVOS), which is designed to show trends in tissue oxygenation, with a four-wavelength laser-based oximeter (FORE-SIGHT), designed to deliver absolute values of tissue oxygenation. Simultaneous values of cerebral tissue oxygenation (StO2) are measured using both devices in 15 term and 15 preterm clinically stable newborns on the first and third day of life. Values are recorded simultaneously in two periods between which oximeter sensor positions are switched to the contralateral side. Agreement between StO2 values before and after the change of sensor position is analyzed. We find that mean cerebral StO2 values are similar between devices for term and preterm babies, but INVOS shows StO2 values spread over a wider range, with wider standard deviations than shown by the FORE-SIGHT. There is relatively good agreement with a bias up to 3.5% and limits of agreement up to 11.8%. Measurements from each side of the forehead show better repeatability for the FORE-SIGHT monitor. We conclude that performance of the two devices is probably acceptable for clinical purposes. Both performed sufficiently well, but the use of FORE-SIGHT may be associated with tighter range and better repeatability of data.

Insights into early brain development from modern brain imaging and outcome studies.

UNLABELLED: Recent brain imaging and outcome studies of infants born at very early gestation have cast new light on brain development at a vulnerable stage. Some of these new developments are reviewed in this editorial. CONCLUSION: The anatomical differences between the brains of babies born extremely prematurely and those born at term appear to translate into disturbances of function. The challenge for paediatricians is to discover the causes, with the aim of promoting normal brain development.

Peripheral haemodynamics in newborns: best practice guidelines.

Peripheral haemodynamics refers to blood flow, which determines oxygen and nutrient delivery to the tissues. Peripheral blood flow is affected by vascular resistance and blood pressure, which in turn varies with cardiac function. Arterial oxygen content depends on the blood haemoglobin concentration (Hb) and arterial pO2; tissue oxygen delivery depends on the position of the oxygen-dissociation curve, which is determined by temperature and the amount of adult or fetal haemoglobin. Methods available to study tissue perfusion include near-infrared spectroscopy, Doppler flowmetry, orthogonal polarisation spectral imaging and the peripheral perfusion index. Cardiac function, blood gases, Hb, and peripheral temperature all affect blood flow and oxygen extraction. Blood pressure appears to be less important. Other factors likely to play a role are the administration of vasoactive medications and ventilation strategies, which affect blood gases and cardiac output by changing the intrathoracic pressure.

The BLISS cluster randomised controlled trial of the effect of 'active dissemination of information' on standards of care for premature babies in England (BEADI) study protocol [ISRCTN89683698].

BACKGROUND: Gaps between research knowledge and practice have been consistently reported. Traditional ways of communicating information have limited impact on practice changes. Strategies to disseminate information need to be more interactive and based on techniques reported in systematic reviews of implementation of changes. There is a need for clarification as to which dissemination strategies work best to translate evidence into practice in neonatal units across England. The objective of this trial is to assess whether an innovative active strategy for the dissemination of neonatal research findings, recommendations, and national neonatal guidelines is more likely to lead to changes in policy and practice than the traditional (more passive) forms of dissemination in England. METHODS/DESIGN: Cluster randomised controlled trial of all neonatal units in England (randomised by hospital, n = 182 and stratified by neonatal regional networks and neonatal units level of care) to assess the relative effectiveness of active dissemination strategies on changes in local policies and practices. Participants will be mainly consultant lead clinicians in each unit. The intervention will be multifaceted using: audit and feedback; educational meetings for local staff (evidence-based lectures on selected topics, interactive workshop to examine current practice and draw up plans for change); and quality improvement and organisational changes methods. Policies and practice outcomes for the babies involved will be collected before and after the intervention. Outcomes will assess all premature babies born in England during a three month period for timing of surfactant administration at birth, temperature control at birth, and resuscitation team (qualification and numbers) present at birth.

Use of tissue oxygenation index and fractional tissue oxygen extraction as non-invasive parameters for cerebral oxygenation. A validation study in piglets.

OBJECTIVE: To evaluate the relation between cerebral tissue oxygenation index (TOI), measured with spatially resolved spectroscopy (SRS), and the different oxygenation parameters. To evaluate the relation between a new parameter named fractional tissue oxygen extraction (FTOE) and the cerebral fractional oxygen extraction (FOE). METHODS: Six newborn piglets were measured at 33, 35, and 37 degrees C and in hypocapnia. Mean arterial blood pressure (MABP), haemoglobin (Hb), peripheral oxygen saturation (S(a)O(2)) and P(a)CO(2) were measured at each step. Cerebral blood flow (CBF) was measured by injection of coloured microspheres into the left atrium. Jugular bulb oxygen saturation (JVS), cerebral arterial and venous oxygen content (C(a)O(2) and C(v)O(2)) and FOE were calculated. TOI of the brain was calculated and FTOE was introduced as (S(a)O(2) - TOI)/S(a)O(2). The correlation was calculated with an ANCOVA test. RESULTS: There was a positive correlation (R = 0.4 and p = 0.011) between TOI and JVS. No correlation was found with CBF, MABP or Hb. There was a positive correlation between P(a)CO(2) and cerebral TOI (R = 0.24 and p = 0.03). FTOE correlated well with FOE (R = 0.4 and p = 0.016) and there was a negative correlation between FTOE and P(a)CO(2) (R = 0.24, p = 0.03). CONCLUSION: The measurement of TOI and FTOE by SRS correlated well with the cerebral venous saturation and FOE, respectively.

Project 27/28: inquiry into quality of neonatal care and its effect on the survival of infants who were born at 27 and 28 weeks in England, Wales, and Northern Ireland.

OBJECTIVE: To identify variations in standards of neonatal care in the first week of life that might have contributed to deaths in infants who were born at 27 and 28 weeks' gestation. METHODS: A case-control study was conducted of infants who were born at 27 and 28 weeks' gestation in England, Wales, and Northern Ireland during a 2-year period. Cases were neonatal deaths; control subjects were randomly selected survivors at day 28. Main outcome measures were failures of prespecified standards of care or deficiencies in care reported by regional panels assessing anonymized medical records. RESULTS: Failures of standards of care relating to ventilatory support (adjusted odds ratio [OR]: 3.29; 95% confidence interval [CI]: 1.97-5.49), cardiovascular support (OR: 2.37; 95% CI :1.36-4.13), and thermal care (OR: 1.71; 95% CI: 1.21-2.43) were associated with neonatal death. Frequencies of unmet resuscitation standards (range: 3%-46%) and of delays in surfactant administration (range: 38%-40%) were similar in cases and control subjects. Panels identified significantly more deficiencies in all aspects of neonatal care in cases with the exception of the management of infection. Stratification by clinical condition of infants at birth showed a stronger association between overall standard of care and death when infants were in a good condition at birth. CONCLUSIONS: Our findings suggest an association between quality of neonatal care and neonatal deaths, most marked for early thermal care and ventilatory and cardiovascular support. Poor overall quality of care was more strongly associated with deaths when the infant was in a good condition at birth.