Neonatal Monitoring Research Articles

Non-contact automatic vital signs monitoring of neonates in NICU using video camera imaging

ABSTRACT Non-contact vital signs monitoring is desirable in both clinical and non-clinical sectors. However, there are limited camera-based studies to monitor the vital signs of neonatal infants in a clinical setting. In this study, a digital camera was used to remotely monitor the heart rate (HR) and respiratory rate (RR) of seven infants at Flinders Medical Centre Neonatal Intensive Care Unit (NICU). The region-of-interest (ROI) was automatically selected based on a skin detection method using skin hue. The experimental results have been validated with the reference data obtained from an ECG monitor, and they showed a strong correlation using the Pearson correlation coefficient, (PCC) .9836 and .9426 for HR and RR, respectively, and a lower error rate with RMSE 2.66 beats/min and 2.93 breaths/min between measured data and reference data. A Bland Altman analysis of the data also presented a close correlation between measured data and reference data for both HR and RR with a mean bias .69 beats/min and .28 breaths/min, and the lower and upper limit of agreement −4.4 to +5.8 beats/min and −5.5 to +6.1 breaths/min, respectively. Therefore, video camera imaging may replace conventional monitoring in NICU and has potential applications in other contexts such as home health monitoring.

Camera fusion for real-time temperature monitoring of neonates using deep learning

The continuous monitoring of vital signs is a crucial aspect of medical care in neonatal intensive care units. Since cable-based sensors pose a potential risk for the immature skin of preterm infants, unobtrusive monitoring techniques using camera systems are increasingly investigated. The combination of deep learning–based algorithms and camera modalities such as RGB and infrared thermography can improve the development of cable-free methods for the extraction of vital parameters. In this study, a real-time approach for local extraction of temperatures on the body surface of neonates using a multi-modal clinical dataset was implemented. Therefore, a trained deep learning–based keypoint detector was used for body landmark prediction in RGB. Image registration was conducted to transfer the RGB points to the corresponding thermographic recordings. These landmarks were used to extract the body surface temperature in various regions to determine the central-peripheral temperature difference. A validation of the keypoint detector showed a mean average precision of 0.82. The registration resulted in mean absolute errors of 16.4 px (8.2 mm) for x and 22.4 px (11.2 mm) for y. The evaluation of the temperature extraction revealed a mean absolute error of 0.55 ^{circ }C. A final performance of 31 fps was observed on the NVIDIA Jetson Xavier NX module, which proves real-time capability on an embedded GPU system. As a result, the approach can perform real-time temperature extraction on a low-cost GPU module.Graphical abstract

Smart bioelectronic pacifier for real-time continuous monitoring of salivary electrolytes

Monitoring electrolytes is critical for newborns and babies in the intensive care unit. However, the gold standard methods use a blood draw, which is painful and only offers discrete measures. Although salivary-based detection offers promise as an alternative, existing devices are ineffective for real-time, continuous monitoring of electrolytes due to their rigidity, bulky form factors, and lack of salivary accumulation. Here, we introduce a smart, wireless, bioelectronic pacifier for salivary electrolyte monitoring of neonates, which can detect real-time continuous sodium and potassium levels without a blood draw. The miniature system facilitates the seamless integration of the ultralight and low-profile device with a commercial pacifier without additional fixtures or structural modifications. The portable device includes ion-selective sensors, flexible circuits, and microfluidic channels, allowing simplified measurement protocols in non-invasive electrolyte monitoring. The flexible microfluidic channel enables continuous and efficient saliva collection from a mouth. By modifying the surface properties of the channels and the structure of the capillary reservoir, we achieve reliable pumping of the viscous medium for quick calibration and measurement. Embedded sensors in the system show good stability and sensitivity: 52 and 57 mV/decade for the sodium and potassium sensor, respectively. In vivo study with neonates in the intensive care unit captures the device's feasibility and performance in the natural saliva-based detection of the critical electrolytes without induced stimulation.

Statistical Description of SaO2–SpO2 Relationship for Model of Oxygenation in Premature Infants

A pulse oximeter model linking arterial (SaO2) and peripheral (SpO2) oxygen saturation is the terminal part of a mathematical model of neonatal oxygen transport. Previous studies have confirmed the overestimation of oxygen saturation measured by pulse oximetry in neonates compared to arterial oxygen saturation and the large variability of measured values over time caused by measurement inaccuracies. This work aimed to determine the SpO2 measurement noise that affects the biased SpO2 value at each time point and integrate the noise description with the systematic bias between SaO2 and SpO2. The SaO2–SpO2 bias was based on previously published clinical data from pathological patients younger than 60 days requiring ventilatory support. The statistical properties of the random SpO2 measurement noise were estimated from the SpO2 continuous recordings of 21 pathological and 21 physiological neonates. The result of the work is a comprehensive characterization of the properties of a pulse oximeter model describing the transfer of the input SaO2 value to the output SpO2 value, including the bias and noise typical for the bedside monitoring of neonates. These results will help to improve a computer model of neonatal oxygen transport.

Proceedings of the 13th International Newborn Brain Conference: Neonatal Neurocritical Care, Seizures, and Continuous EEG monitoring.

Proceedings of the 13th International Newborn Brain Conference: Neonatal Neurocritical Care, Seizures, and Continuous EEG monitoring.

Optimizing Vancomycin Dosing and Monitoring in Neonates and Infants Using Population Pharmacokinetic Modeling.

We determined optimal vancomycin starting dose regimens in infants ≤180 days of age to achieve the highest probability of target attainment with an area under the concentration-time curve for 24 h (AUC24) of ≥400 using population pharmacokinetic (PK) modeling. Secondarily, determination of the relationship between serum creatinine (SCR) and vancomycin clearance in neonates was done. A retrospective population PK study was designed and included pediatric patients ≤180 days old who had received vancomycin and had a serum vancomycin concentration sampled. A population PK model was developed using Pumas (v1.0.5). Simulation was performed with various dosing regimens to evaluate the probability of AUC24 target attainment and probability of trough of ≤20 mg/liter, and comparison to published models was performed. Individual clearance estimates, obtained from the final model, were plotted against SCR and faceted by age quartiles to assess the relationship between SCR and vancomycin clearance. A total of 934 patients were included in the study (58.6% male; median age, 43.6 days [range of 0 to 184]; median number of concentration samples, 1 [range of 1 to 29]). A one-compartment model was developed with body weight (WT), SCR, and postmenstrual age (PMA) identified as significant covariates on clearance. Plotting vancomycin clearance versus SCR demonstrated no clear relationship between the two at <10 days postnatal age (PNA). Dosing regimens to attain AUC24 and trough targets were stratified according to SCR for ≥10 days PNA and PMA for <10 days PNA. A vancomycin population PK model was developed for pediatric patients <180 days of age incorporating WT, SCR, and PMA. The relationship between vancomycin clearance and serum creatinine is not clear at <10 days PNA.

A Suitable Therapeutic Drug Monitoring Method for Amoxicillin in Plasma by High Performance Liquid Chromatography–UV (HPLC–UV) in Neonates

Amoxicillin, a broad-spectrum β-lactam antibiotic, is widely used for treatment of neonatal infections. Despite the unmet need in neonates, an adapted analytical method is still missing in clinical practice. The purpose of this study was to develop and test an easy and credible high performance liquid chromatography–UV (HPLC–UV) method to determine amoxicillin in small volumes of human plasma and use it in routine therapeutic drug monitoring (TDM) of neonates. After a protein precipitation, amoxicillin for standards, quality control samples, and patient samples were separated by LC and measured by UV detection, and tinidazole was used as the internal standard. The calibration range was 0.50–20.0 μg/mL. Intra- and inter-day precisions were less than 4.7%. The acceptance criteria of accuracy (between 85–115%) were met in all cases. A plasma volume of 50 μL was required to achieve the limit of quantification of 0.50 μg/mL. Thus, a simple, rapid, and accurate HPLC–UV method has been developed to detect the concentration of amoxicillin in human plasma. This method was adapted to do TDM of amoxicillin in neonates.

A multi‐metric movement model for identifying elk parturition events

AbstractFor wildlife managers, identifying the time and location of ungulate parturition events is necessary to protect parturition habitat and inform population models. Current methods for identifying parturition events include neonatal capture and monitoring and visual analysis of location data, which are resource intensive and subject to biases. Recently, movement‐based analyses using the spatial and temporal patterns contained in location data have shown promise for identifying parturition behavior; however, questions regarding efficacy and best practice have limited the adoption of such movement‐based parturition models into management programs. We used location data collected between 2017−2018 from a California population of female Roosevelt elk with known parturition status to build a set of movement‐based models. We compared each model's ability to accurately classify individual's parturition status and identify the timing of parturition. The top model showed that within 72 hours of a parturition event, elk made smaller movements, had smaller home ranges, and had longer visits to individual locations. Of the 16 individuals in our study with known parturition status, our approach to classifying an individual's status was 81% accurate in cross‐validation, which increased to 100% accuracy when the complete dataset was used to train the top model. We then used the top, global and single‐metric models to establish probability thresholds and identify parturition events for collared‐elk with unknown parturition status. Our results align with a growing number of studies that have shown movement‐based parturition models are a reliable method that could augment or replace field‐based techniques for identifying parturition events and quantifying parturition rates in ungulate populations.

Near-Infrared Spectroscopy as a Hemodynamic Monitoring Tool during Neonatal Extracorporeal Life Support: A Case Series

Near-infrared spectroscopy (NIRS) is a non-invasive clinical tool allowing for real-time, continuous measurement of regional tissue oxygenation (rSO2); though predominantly used for neuromonitoring, it also has the potential for early detection of hemodynamic compromise in the patients on extracorporeal life support (ECLS). The authors present two cases of neonates for whom continuous monitoring of multisite rSO2with NIRS provided the first indication of a significant compromise in hemodynamic status from catastrophic hemorrhagic complications while on ECLS ahead of conventional ECLS monitoring parameters. Routine NIRS monitoring of neonates on ECLS has utility for ongoing assessment of hemodynamic status and can be used for early detection of complications leading to impaired tissue perfusion.

Neonatal Impedance Cardiography in Asphyxiated Piglets-A Feasibility Study.

ObjectivesImpedance cardiography (ICG) is a non-invasive method for continuous cardiac output measurement and has the potential to improve monitoring and treatment of sick neonates. PhysioFlow® is a signal-morphology ICG-system showing promising results in adults with low and high cardiac output, but no data from neonates or neonatal models exist. The aim of this study was to investigate PhysioFlow® feasibility in asphyxiated newborn piglets.MethodsFifteen piglets, under continuous arterial heart rate (HR) and blood pressure (BP) monitoring, were asphyxiated until asystole. Cardiopulmonary resuscitation was performed and the piglets monitored after return of spontaneous circulation (ROSC). Arterial lactate was measured at baseline, every 5 min throughout asphyxiation, at asystole, and at 10 min and later every 30 min after ROSC. PhysioFlow® measured cardiac stroke volume (SV) and HR, and calculated cardiac index (CI) (L/m2/min). Registrations with a signal quality < 75% were excluded, and registrations recorded for 30 min from start of asphyxia analyzed. Pearson correlations were calculated for CI; and HR, mean BP and blood lactate.ResultsThe piglets were asphyxiated for median (interquartile range) 30 (20–35) min and had a lactate at asystole of 15.0 (9.1–17.0) mmol/L. Out of a total of 20.991 registrations in all animals combined, there were 10.148 (48.3%) registrations with a signal quality ≥ 75%. Signal quality ≥ 75% varied in individual piglets from 7 to 82% of registrations. We analyzed 1.254 registrations recorded 30 min from initiation of asphyxia, i.e., in piglets with brief asphyxia times, this included cardiopulmonary resuscitation and post-ROSC observation. There was a positive correlation between CI and SVI (r = 0.90, p < 0.001), and between CI and HR (r = 0.446, p < 0.001). There was no correlation between CI, or mean BP or lactate (p = 0.98 and 0.51, respectively).ConclusionAbout half of ICG-registrations in asphyxiated piglets were of good quality. However, signal quality was highly variable between piglets. In total, there was a higher proportion of reliable ICG-registrations than reported from clinical delivery room studies using electrical velocimetry. Our data are physiologically plausible and supports further research evaluating PhysioFlow® for cardiac output monitoring in perinatal asphyxia. In particular, factors influencing inter-individual variations in signal quality should be explored.

ОСОБЕННОСТИ ПОКАЗАТЕЛЕЙ ЗДОРОВЬЯ НЕДОНОШЕННЫХ ДЕТЕЙ В ПЕРИОДЕ РАННЕГО ДЕТСТВА В ЗАВИСИМОСТИ ОТ СРОКА ГЕСТАЦИИ ПРИ РОЖДЕНИИ

Despite the great success in the care of premature babies in recent years, the incidence and disability of this contingent remain high. The aim of the study was to analyze the health indicators of premature babies in the first 3 years of life. Materials and methods of research: a singlecenter cohort retrospective comparative continuous study was carried out for the period from 2016/01/01 to 2020/12/31. The study included 1113 premature babies (598 boys and 515 girls) with a gestational age of 24 to 36 weeks at the age of 3 months up to 3 years. The sample size was not pre-calculated. Results: it was found that more than 50% of children with a gestational age of less than 32 weeks are at risk of developing diseases of the nervous system – 24.8% (p=0.032), the organs of sight – 1.3% (p=0.023) and the respiratory system – 27.6% (p=0.18). Conclusion: tactics of neonatal nursing and monitoring of the child after discharge from the hospital are important for improving the outcomes of morbidity in premature infants.

Expert consensus on grading management of electroencephalogram monitoring in neonates.

Neonatal electroencephalogram (EEG) monitoring guidelines have been published by American Clinical Neurophysiology Society, and the expert consensus on neonatal amplitude-integrated EEG (aEEG) has also been published in China. It is difficult to strictly follow the guidelines or consensus for EEG monitoring in different levels of neonatal units due to a lack of EEG monitoring equipment and professional interpreters. The Subspecialty Group of Neonatology, Society of Pediatrics, Chinese Medical Association, established an expert group composed of professionals in neonatology, pediatric neurology, and brain electrophysiology to review published guidelines and consensuses and the articles in related fields and propose grading management recommendations for EEG monitoring in different levels of neonatal units. Based on the characteristics of video EEG and aEEG, local medical resources, and disease features, the expert group recommends that video EEG and aEEG can complement each other and can be used in different levels of neonatal units. The consensus also gives recommendations for promoting collaboration between professionals in neonatology, pediatric neurology, and brain electrophysiology and implementing remote EEG monitoring.

Expert consensus on minimum technical standards for neonatal electroencephalography operation and report writing.

Electroencephalography (EEG) monitoring is an important examination method in the management of critically ill neonates, which can be used to evaluate brain function and developmental status, severity of encephalopathy, and seizures and predict the long-term neurodevelopmental outcome of high-risk neonates with brain injury. EEG monitoring for neonates is different from that for adults and children, and its operation and interpretation are easily affected by the number of recording electrodes, electrode montage, and monitoring quality. Therefore, standard operation must be followed to ensure the quality of signal acquisition and correct interpretation, thereby ensuring proper management of critically ill neonates. The Subspecialty Group of Neonatology, Society of Pediatrics, Chinese Medical Association established an expert group composed of professionals in neonatology and brain electrophysiology to perform a literature review, summarize the minimum technical standards for neonatal EEG monitoring, and develop the expert consensus on minimum technical standards for neonatal EEG operation and report writing. This consensus will provide guidance for neonatal EEG operation, including technical parameters of EEG monitoring device, operation procedures of EEG monitoring, and specifications for report writing.

Variability of respiratory rate measurements in neonates- every minute counts

BackgroundRespiratory rate is difficult to measure, especially in neonates who have an irregular breathing pattern. The World Health Organisation recommends a one-minute count, but there is limited data to support this length of observation. We sought to evaluate agreement between the respiratory rate (RR) derived from capnography in neonates, over 15 s, 30 s, 120 s and 300 s, against the recommended 60 s.MethodsNeonates at two hospitals in Nairobi were recruited and had capnograph waveforms recorded using the Masimo Rad 97. A single high quality 5 min epoch was randomly chosen from each subject. For each selected epoch, the mean RR was calculated using a breath-detection algorithm applied to the waveform. The RR in the first 60 s was compared to the mean RR measured over the first 15 s, 30 s, 120 s, full 300 s, and last 60 s. We calculated bias and limits of agreement for each comparison and used Bland-Altman plots for visual comparisons.ResultsA total of 306 capnographs were analysed from individual subjects. The subjects had a median gestation age of 39 weeks with slightly more females (52.3%) than males (47.7%). The majority of the population were term neonates (70.1%) with 39 (12.8%) having a primary respiratory pathology. There was poor agreement between all the comparisons based on the limits of agreement [confidence interval], ranging between 11.9 [− 6.79 to 6.23] breaths per minute in the one versus 2 min comparison, and 34.7 [− 17.59 to 20.53] breaths per minute in the first versus last minute comparison. Worsening agreement was observed in plots with higher RRs.ConclusionsNeonates have high variability of RR, even over a short period of time. A slight degradation in the agreement is noted over periods shorter than 1 min. However, this is smaller than observations done 3 min apart in the same subject. Longer periods of observation also reduce agreement. For device developers, precise synchronization is needed when comparing devices to reduce the impact of RR variation. For clinicians, where possible, continuous or repeated monitoring of neonates would be preferable to one time RR measurements.

Clinical Profile of Hypoglycaemia in Neonates at Risk in a Tertiary Care Teaching Institute in Southern India: A Longitudinal Study

Introduction: Hypoglycaemia is common in babies at risk. Without early detection, timely diagnosis and treatment, hypoglycaemia can cause disastrous consequences on neurological and developmental outcomes. Therefore, continuous monitoring of blood glucose levels in babies at risk should be done to reduce its impact. Aim: To describe the clinical profile and sequential blood sugar levels in the first four postnatal days in at-risk neonates and to identify the risk group of neonates with recurrent hypoglycaemia. Materials and Methods: This was a longitudinal study done in the Neonatal Intensive Care Unit (NICU) and Special Newborn Care Unit (SNCU) of a tertiary care teaching institute; Sri Avittam Thirunal Hospital (SATH), Government Medical College, Thiruvananthapuram, Kerala, India, from October 2017 to October 2018. Neonates admitted with risk factors for hypoglycaemia according to ‘National Neonatology Forum’ clinical guidelines with low capillary blood sugar (&lt;40 mg/dL) within the first two to four hours of life were included in the study. These neonates were followed-up clinically till fourth postnatal day with glucose monitoring. Statistical analysis was done using Statistical Package for the Social Sciences (SPSS) software version 22. Categorical variables were expressed as proportions and compared using the Chi-square test. A p-value &lt;0.05 was considered statistically significant. Results: A total of 368 ‘at risk’neonates had hypoglycaemia at admission (2 to 4 hours) and of these 200 (54.3%) developed recurrent hypoglycaemia. Out of the neonates with recurrent hypoglycaemia, 150 (75%) were preterm and 50 (25%) were term. The preterm Small for Gestational Age (SGA) had a higher chance of developing recurrent hypoglycaemia than preterm Appropriate for Gestational Age (AGA) and Large for Gestational Age (LGA) (p-value=0.0256). Although, 102 (40.2%) preterm had asymptomatic hypoglycaemia, 90 (78.9%) term neonates showed symptoms of hypoglycaemia. The major clinical manifestation was jitteriness in those with a single episode 31 (18.45%) and lethargy/poor activity in those with more than one episode 66 (33%). The blood glucose levels less than 25 mg/dL at admission was significantly associated with the occurrence of a repeat episode of hypoglycaemia (p-value=0.028). Conclusion: Blood glucose monitoring in neonates with risk factors is mandatory as 54.3% of neonates developed recurrent hypoglycaemia. Of these, preterm SGA had a high chance of developing recurrent hypoglycaemia. The variable presentations in neonatal hypoglycaemia indicates the need for detailed and thorough clinical examination with glucose monitoring in these at-risk neonates. Initial blood glucose level less than 25 mg/dL was significantly associated with recurrent hypoglycaemia.

Laboratory Diagnosis of Cerebral Creatine Deficiency Syndromes by Determining Creatine and Guanidinoacetate in Plasma and Urine.

Cerebral creatine deficiency syndromes are caused by the dysfunctional creatine biosynthesis or transport and comprise three hereditary neurodevelopmental defects including arginine-glycine amidinotransferase (AGAT), guanidinoacetate methyltransferase (GAMT), and creatine transporter deficiencies. All conditions are characterized by seizures, intellectual disability, and behavioral abnormalities. Laboratory diagnosis of these disorders relies on the determination of creatine and guanidinoacetate concentrations in both plasma and urine. Here we describe a rapid quantitative UPLC/MS/MS method for the simultaneous determination of these analytes using a normal-phase HILIC column after analyte derivatization. The approach is suitable for neonatal screening follow-ups and monitoring of the treatment for creatine deficiency syndromes.

Qualitative study exploring the feasibility, usability and acceptability of neonatal continuous monitoring technologies at a public tertiary hospital in Nairobi, Kenya

ObjectiveTo assess the feasibility, usability and acceptability of two non-invasive, multiparameter, continuous physiological monitoring (MCPM) technologies for use in neonates within a resource-constrained healthcare setting in sub-Saharan Africa.DesignA qualitative study...

Cerebral Oxygenation and Activity During Surgical Repair of Neonates With Congenital Diaphragmatic Hernia: A Center Comparison Analysis.

Background and aim: Neonatal brain monitoring is increasingly used due to reports of brain injury perioperatively. Little is known about the effect of sedatives (midazolam) and anesthetics (sevoflurane) on cerebral oxygenation (rScO2) and cerebral activity. This study aims to determine these effects in the perioperative period.Methods: This is an observational, prospective study in two tertiary pediatric surgical centers. All neonates with a congenital diaphragmatic hernia received perioperative cerebral oxygenation and activity measurements. Patients were stratified based on intraoperatively administrated medication: the sevoflurane group (continuous sevoflurane, bolus fentanyl, bolus rocuronium) and the midazolam group (continuous midazolam, continuous fentanyl, and continuous vecuronium).Results: Intraoperatively, rScO2 was higher in the sevoflurane compared to the midazolam group (84%, IQR 77–95 vs. 65%, IQR 59–76, p = < 0.001), fractional tissue oxygen extraction was lower (14%, IQR 5–21 vs. 31%, IQR 29–40, p = < 0.001), the duration of hypoxia was shorter (2%, IQR 0.4–9.6 vs. 38.6%, IQR 4.9–70, p = 0.023), and cerebral activity decreased more: slow delta: 2.16 vs. 4.35 μV2 (p = 0.0049), fast delta: 0.73 vs. 1.37 μV2 (p = < 0.001). In the first 30 min of the surgical procedure, a 3-fold increase in fast delta (10.48–31.22 μV2) and a 5-fold increase in gamma (1.42–7.58 μV2) were observed in the midazolam group.Conclusion: Sevoflurane-based anesthesia resulted in increased cerebral oxygenation and decreased cerebral activity, suggesting adequate anesthesia. Midazolam-based anesthesia in neonates with a more severe CDH led to alarmingly low rScO2 values, below hypoxia threshold, and increased values of EEG power during the first 30 min of surgery. This might indicate conscious experience of pain. Integrating population-pharmacokinetic models and multimodal neuromonitoring are needed for personalized pharmacotherapy in these vulnerable patients.Trial Registration: https://www.trialregister.nl/trial/6972, identifier: NL6972.

A case of new-onset SLE during pregnancy an initial manifestation with all diagnostic criteria: The challenges of diagnosis and managing a complex disease in a low resource setting

Systemic lupus erythematosus (SLE) is a complex chronic multiorgan autoimmune disease. When newly diagnosed during pregnancy or puerperium, it is known as new-onset SLE during pregnancy. Delayed or missed diagnosis of newonset SLE during pregnancy may occur due to similar clinical manifestation of SLE with normal physiological changes of pregnancy and lupus nephritis with preeclampsia. New-onset SLE during pregnancy has major organ involvement with poor maternal and foetal outcomes. Management options are limited due to teratogenic side effects of drugs in pregnancy. This is further compounded in a low resource setting with lack of health seeking behaviours and inadequate access to timely care. Multidisciplinary management with close medical, obstetric, neonatal monitoring, patient education and improved access to care is essential for better outcomes. Our aim is to report a 19 year old primigravida with new onset SLE in pregnancy and multiorgan involvement fulfilling all criteria for diagnosis of SLE at the first presentation.

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.