Around 5%-10% of newborn babies require some form of resuscitation at birth and heart rate (HR) is the best guide of efficacy. We report the development and first trial of a device that continuously monitors neonatal HR, with a view to deployment in the delivery room to guide newborn resuscitation. The device uses forehead reflectance photoplethysmography (PPG) with modulated light and lock-in detection. Forehead fixation has numerous advantages including ease of sensor placement, whilst perfusion at the forehead is better maintained in comparison to the extremities. Green light (525 nm) was used, in preference to the more usual red or infrared wavelengths, to optimize the amplitude of the pulsatile signal. Experimental results are presented showing simultaneous PPG and electrocardiogram (ECG) HRs from babies (n = 77), gestational age 26-42 weeks, on a neonatal intensive care unit. In babies ⩾32 weeks gestation, the median reliability was 97.7% at ±10 bpm and the limits of agreement (LOA) between PPG and ECG were +8.39 bpm and -8.39 bpm. In babies <32 weeks gestation, the median reliability was 94.8% at ±10 bpm and the LOA were +11.53 bpm and -12.01 bpm. Clinical evaluation during newborn deliveries is now underway.
BackgroundAlthough international newborn resuscitation guidance has been in force for some time, there are no UK data on current newborn resuscitation practices.ObjectiveEstablish delivery room (DR) resuscitation practices in the UK, and identify any differences between neonatal intensive care units (NICU), and other local neonatal services.MethodsWe conducted a structured two-stage survey of DR management, among UK neonatal units during 2009–2010 (n = 192). Differences between NICU services (tertiary level) and other local neonatal services (non-tertiary) were analysed using Fisher's exact and Student's t-tests.ResultsThere was an 89% response rate (n = 171). More tertiary NICUs institute DR CPAP than non-tertiary units (43% vs. 16%, P = 0.0001) though there was no significant difference in frequency of elective intubation and surfactant administration for preterm babies. More tertiary units commence DR resuscitation in air (62% vs. 29%, P < 0.0001) and fewer in 100% oxygen (11% vs. 41%, P < 0.0001). Resuscitation of preterm babies in particular, commences with air in 56% of tertiary units. Significantly more tertiary units use DR pulse oximeters (58% vs. 29%, P < 0.01) and titrate oxygen based on saturations. Almost all services use occlusive wrapping to maintain temperature for preterm infants.ConclusionsIn the UK, there are many areas of good evidence based DR practice. However, there is marked variation in management, including between units of different designation, suggesting a need to review practice to fulfil new resuscitation guidance, which will have training and resource implications.
The effects of permanent circumflex coronary artery occlusion (PO) compared with reestablishing blood flow (OR) at 2 and 6 h after occlusion on the final extent of histological infarction (HI) was assessed in chronically instrumented awake dogs. The relationships between the extent of left ventricular ischemia measured by microsphere techniques and HI in the PO group were used as models to predict the expected infarction in the 2- and 6-h OR groups. Mean HI (+/-SD) in the PO and 6- and 2-h OR groups was 21 +/- 13, 19 +/- 10, and 13 +/- 12% of left ventricular weight, respectively; values were not significantly different. The extent of HI in samples grouped according to epicardial and endocardial layers and ischemic blood flow ranges (0-15, 16-30, 31-50, 51-75% of control region blood flow) was reduced in the 2-h but not 6-h OR group. Analysis of individual animals using total ischemic region blood flow to epicardial and endocardial layers demonstrated that OR at 2 h but not 6 h reduced infarction in most animals but not in certain animals with the largest ischemic regions.
Background Heart rate (HR) is considered the most reliable indicator of successful newborn resuscitation. Current recommended assessment is by auscultation but this is subject to human error1 and can interrupt resuscitation. Pulse oximetry is sometimes used but is subject to long acquisition times and poor signal with reduced perfusion.2 An improved method of monitoring HR during these crucial minutes may optimise outcomes for infants requiring resuscitation. Aims To validate a novel, reflectance photoplethysmographic sensor to measure HR. Advantages of this device include (1) forehead placement reduces the risk of hypothermia in preterm infants, (2) Rapid placement and acquisition time,3 (3) reliable in poor perfusion states, (4) continuous and hands free. Methods We evaluated the sensor in 50 infants (26–42 weeks gestation) admitted to our Neonatal Intensive Care Unit. The sensor was on the forehead and 20-min recordings made with simultaneous routine ECG monitoring to provide the comparator. Reliability was calculated as the percentage positive agreement within 5 bpm of the ECG HR. Results Data were excluded for six infants due to poor or incomplete ECG traces. Overall median agreement with ECG was 88% (IQR 79%, 95%). Conclusion Our novel sensor detects a pulsatile signal in stable newborn infants with reliability ≥88% for a clinically useful agreement of +/−5 bpm. We identified motion artefact as a significant contributor to reduced reliability and are optimising sensor fixation to reduce this. Ongoing trials to validate this device among term and preterm infants in the delivery room are underway.
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Methods: Retrospective review of moderately LBW infants admitted to the SCBU in the Rotunda with birth weights >1800g and < 2500g. Patients were identified using the unit database; further information obtained from chart review where necessary. All infants had temperature recorded on admission.Results: 340 infants fulfilled the weight criteria. 44% of these were hypothermic on admission: 27% had mild hypothermia (36-36.4°C); 17% had moderate hypothermia (32-35.9°C). No patients had severe hypothermia. The lowest recorded temperature was 34° C. Overall rate of hypothermia in this group: 44% versus 32.4% in infants >2.5kg. Conclusion:A significant number (44%) of LBW infants weighing 1.8 to 2.5kg admitted to the SCBU had mild to moderate hypothermia. The rate of hypothermia in larger infants (>2.5kg) was 32%. This indicates the need for improving practices to prevent hypothermia in the delivery room and during transfer of LBW infants. Aims: Develop a user friendly, quick and reliable forehead HR sensor for use in newborn infants requiring delivery room resuscitation. HEARTLIGHT -DELIVERY ROOM ACQUISITION TIME FOR A NOVEL FOREHEAD HEART RATE SENSOR FOR NEWBORN RESUSCITATION Methods:We have developed a forehead HR sensor (HeartLight), utilising patented reflectance photoplethysmography technology, to detect changes in pulse volume with a rapid acquisition time. The HeartLight can be sited within ten seconds. Following development in the NICU, we examined the acquisition time of the HeartLight sensor in the delivery room in term newborn babies (birth weight 3263±486g, n=16). Time to acquire a reliable signal was measured from the time the sensor was activated.Results: Median time to obtain the first two consecutive pulsations was 1.8 seconds (IQR 1.4-8.0s) and first ten consecutive pulsations was 13.2 seconds
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