Konrad Heimann

Neonatal non-contact respiratory monitoring based on real-time infrared thermography

BackgroundMonitoring of vital parameters is an important topic in neonatal daily care. Progress in computational intelligence and medical sensors has facilitated the development of smart bedside monitors that can integrate multiple parameters into a single monitoring system. This paper describes non-contact monitoring of neonatal vital signals based on infrared thermography as a new biomedical engineering application. One signal of clinical interest is the spontaneous respiration rate of the neonate. It will be shown that the respiration rate of neonates can be monitored based on analysis of the anterior naris (nostrils) temperature profile associated with the inspiration and expiration phases successively.ObjectiveThe aim of this study is to develop and investigate a new non-contact respiration monitoring modality for neonatal intensive care unit (NICU) using infrared thermography imaging. This development includes subsequent image processing (region of interest (ROI) detection) and optimization. Moreover, it includes further optimization of this non-contact respiration monitoring to be considered as physiological measurement inside NICU wards.ResultsContinuous wavelet transformation based on Debauches wavelet function was applied to detect the breathing signal within an image stream. Respiration was successfully monitored based on a 0.3°C to 0.5°C temperature difference between the inspiration and expiration phases.ConclusionsAlthough this method has been applied to adults before, this is the first time it was used in a newborn infant population inside the neonatal intensive care unit (NICU). The promising results suggest to include this technology into advanced NICU monitors.

Are recurrent hyperglycemic episodes and median blood glucose level a prognostic factor for increased morbidity and mortality in premature infants </=1500 g?

Abstract Background: Tight blood glucose control with intravenous insulin reduces morbidity and mortality in adult surgical intensive care patients. This has never been investigated in premature infants weighing ≤1500 g. We investigate the relationship between blood glucose levels repeatedly elevated >150 mg/dL and median blood glucose levels in the first week of life on one hand, and morbidity and mortality in premature infants weighing ≤1500 g on the other. Patients and methods: The following data were collected from 252 premature infants weighing ≤1500 g at birth: demographic data, blood glucose levels at three set times during the day (capillary and arterial) in the first week of life, actual and relative elevation of blood glucose level ≥150 mg/dL, median blood glucose level, allocation of patients into groups according to number of elevated blood glucose levels ≥150 mg/dL (0, 1–3 or ≥4 incidents), and median blood sugar level in relation to mortality and morbidity like IVH, ROP, and sepsis. Results: A significant increase in mortality (P<0.0001) with increasing median blood glucose level and repeated (≥4) incidents of blood glucose levels ≥150 mg/dL and in infants with low gestational age (<27 weeks) were observed. There was no correlation between blood glucose level and morbidity. Conclusion: Premature infants with low gestational age (<27 weeks), elevated median blood glucose levels and/or repeatedly elevated blood glucose levels ≥150 mg/dL have a significantly increased mortality. However, further prospective studies considering the gestational age should determine the relationship between tight glucose control and mortality.

Impact of Skin to Skin Care, Prone and Supine Positioning on Cardiorespiratory Parameters and Thermoregulation in Premature Infants

Background: Skin to skin care (SSC), prone (PP) and supine (SP) positions are standard positions in daily care for premature infants. Their influence on cardiorespiratory parameters and thermoregulation is discussed controversially. Objectives: We compared SSC with PP, the recommended position for preterm infants, and SP, the safest position for term infants, and tested the hypothesis that SSC has no impact on cardiorespiratory parameters and thermoregulation. Methods: In 18 spontaneously breathing premature infants [median gestational 28 weeks (24–32); chronological age 36 days (7–64), and weight 1,543 g (750–2,100)], heart and respiratory rate, breathing pattern, episodes of desaturation (<85 but ≧80 and <80%), oxygen saturation and rectal temperature were analyzed with polygraphy (Alice 3® and 3.5®) in a 6-hour measuring cycle of three subsequent series (120 min each in SP, SSC and PP) and compared (Wilcoxon test). Results: During SSC, we found no increase in apneic attacks and bradycardic episodes and no difference in respiratory rate, breathing pattern, oxygen saturation, episodes and duration of desaturation compared to SP and PP. Episodes of desaturation <85 but ≧80 and <80% were more frequent in SP compared to PP (p = 0.0421 and p = 0.0319). Heart rate increased in SSC and PP compared to SP (154.86 bpm, SD 11.55, and 153.33 bpm, SD 15.95 vs. 150.25 bpm, SD 14.64; p = 0.0013 and p = 0.0346). Temperature level was not significantly higher during SSC and PP compared to SP except a rise between the start and the end of the 6-hour measuring cycle (37.05°C, SD 0.2 vs. 37.30°C, SD 0.3; p = 0.0436). Conclusion: We found no significant SSC-mediated changes in quality and quantity of desaturations and in body temperature compared to PP in preterm infants.

Three new cases of congenital agenesis of the trachea

Congenital absence of the trachea is a rare anomaly that might confront the obstetrician or neonatologist with an unexpected emergency. These patients present with cyanosis, severe respiratory distress, insufficient gas exchange, absence of audible crying and difficult or impossible endotracheal intubation. In more than 90% it is associated with further congenital malformations. Adequate oxygenation depends on the existence of a tracheo- or bronchooesphageal fistula and the length of the proximal trachea. We present the cases of three neonates with tracheal agenesis with tracheooesophageal fistula. Two of the neonates died within the first hour of life because endotracheal intubation was impossible and oxygenation through an oesophageally placed tube was insufficient. The third infant could be oxygenated through a tracheooesophageal fistula. The ventilation was at least insufficient and no surgical intervention was made. The diagnosis of a congenital absence of the trachea usually is made after birth because of the clinical signs and the course within the first minutes of life. The only way that the diagnosis can be made prenatally is by magnetic resonance imaging (MRI). The knowledge of this clinical picture helps to make decisions in an unexpected emergency in the immediate postpartum period and also in patients whose ventilation is very difficult right from the start.

Infrared thermography for detailed registration of thermoregulation in premature infants.

Abstract Objective: To evaluate skin temperature by using different positions with non-contact infrared thermography (IRT) in multiple body areas of preterm infants for detailed information about temperature regulation and distribution. Methods: The temperature of ten premature infants (median: 27 weeks; age 36 days; weight 1322 g) was determined via IRT (leg, back, arm, head, upper abdomen; diameter 1 cm, scale 0.00°C), and comparison was made with two conventional sensors. There were measurements of 10 min each: first incubator phase (I1), standardized skin-to-skin care (SSC) at the beginning (SSC1), after 90 min (SSC2), and then there was a second incubator phase (I2). Results: From I1 to SSC1, patients cooled down (max. 0.62°C; both methods). From SSC1 to SSC2 temperature on central areas (abdomen, back) was maintained but rose distinctively on the head and leg (P<0.05). In the incubator (I2), temperature niveau in all IRT-areas was significantly lower than before SSC. Conclusion: Via IRT, it is possible to detect fluctuations in temperature of premature infants. The cooling in I2 after SSC should be taken into account before routine daily care.

Multichannel simultaneous magnetic induction measurement system (MUSIMITOS)

Non-contact heart and lung activity monitoring would be a desirable supplement to conventional monitoring techniques. Based on the potential of non-contact magnetic induction measurements, requirements for an adequate monitoring system were estimated. This formed the basis for the development of the presented extendable multichannel simultaneous magnetic induction measurement system (MUSIMITOS). Special focus was given to the dynamic behaviour and simultaneous multichannel measurements, so that the system allows for up to 14 receiver coils working simultaneously at 6 excitation frequencies. Moreover, a real-time software concept for online signal processing visualization in combination with a fast software demodulation is presented. Finally, first steps towards a clinical application are pointed out and technical performance as well as first in vivo measurements are presented. This paper covers some aspects previously presented in Steffen and Leonhardt (2007 Proc. 13th Int. Conf. on Electrical Bioimpedance and the 8th Conf. on Electrical Impedance Tomography, Graz 2007).

Idiopathic Growth Hormone Deficiency: A Vanishing Diagnosis?

Some non-organic causes for growth hormone (GH) deficiency (GHD) can be attributed to genetic defects within the hypothalamo-pituitary axis. Using modern molecular biology techniques micromutations within the GH and GH-releasing hormone receptor genes have been detected as a rare cause of isolated GHD. Combined pituitary hormone deficiencies (CPHD), on the other hand, are associated with defects that manifest during the organogenesis of the anterior pituitary gland. In recent years an increasing number of patients with CPHD has been reported, showing mutations within pituitary transcription factors Pit-1, Prop-1 and HesX1. Such defects can be observed with different frequencies in patients. Some disorders, such as CPHD due to Pit-1 mutations, display a hormonal phenotype that seems more or less invariable. In most other forms of genetic CPHD both the combination and severity of anterior pituitary hormone deficiencies vary considerably. Ongoing research concentrates on factors involved in the differentiation and proliferation of cells that belong to the hypothalamo-pituitary growth axis. As not every possible candidate turns out to be a frequent cause of GHD or CPHD in humans, it will be many more years before the term ‘idiopathic’ becomes a vanishing attribute to the clinical diagnosis of pituitary insufficiency.

[Non-contact monitoring of heart and lung activity using magnetic induction measurement in a neonatal animal model].

Zusammenfassung Hintergrund: Die magnetische Bioimpedanzmessung (MBM) ermöglicht die Bestimmung des Widerstandes in biologischem Gewebe mit Hilfe von magnetischen Wechselfeldern, d.h. sich zeitlich ändernden Magnetfeldern. Diese entstehen, wenn im Körper leitende Fluide bei Atemtätigkeit (Luft, schlecht leitend) oder Herzaktion (Blut, gut leitend) verschoben werden. Als Folge verändert sich die Widerstandsverteilung im Thorax, und es kommt zur Verschiebung seines Gesamtwiderstandes. Mittels Spulen werden diese Veränderungen kontaktlos registriert und aufgezeichnet. Dieses Messprinzip wurde bisher in einem Tiermodell mit ausgewachsenen Schweinen und bei gesunden Erwachsenen angewandt. Ein neonatales Tiermodell existiert nicht. Unser Ziel war es, mittels MBM kontaktlos Atemtätigkeit und Herzaktion bei neugeborenen Ferkeln zu messen, um dieses Verfahren gegebenenfalls als Modell zur Evaluation von Störungen der Herz- und Atemfunktion im Neugeborenenalter zu testen. Material und Methode: Mittels 5 Spulen (3 Mess- und 2 Erregerspulen) im Boden eines Experimentalinkubators wurde bei 16 analgosedierten Ferkeln simultan die Veränderung der magnetischen Induktion in Abhängigkeit von Herzaktion und Atemtätigkeit gemessen und mit einem Pulsoxymeter (Monitorsystem Sirecust 404 N) und einem Atemflussdetektor (Strömungswiderstand und Differenzdrucksensor) als Referenzsignale verglichen. Neben Spontanatmung wurden die Tiere unter Continuous Positive Airway Pressure (CPAP, Atemunterstützung zur Verhinderung des endexpiratorischen Alveolarkollapses,) (Flow 8 l/min, PEEP 5 cm H2O), konventioneller Beatmung (inspiratorischer Druck 14 mm Hg, Frequenz 40/min) und Hochfrequenzoszillation (HFOV, Beatmungsverfahren bei Lungenversagen) (Frequenz 10 Hz, Mitteldruck 10 mm Hg, Amplitude 1,5) untersucht. Die Erkennung der Atemtätigkeit durch MBM, im Vergleich zum Referenzsignal, wurde anhand der prozentualen Detektionsrate „korrekt registrierter Atemzüge“ (95-%-Konfidenzintervall) beurteilt. Zur Quantifizierung der Übereinstimmung zwischen MBM und Referenzmessung in der Herzfrequenz wurden der Konkordanzkorrelationskoeffizient (KKK) nach Lin (95% Konfidenzintervall) und der Bland-Altman-Plot herangezogen. Ergebnisse und Diskussion: Die Detektionsrate der Atemtätigkeit für MBM im Vergleich zum Referenzsignal lag unter CPAP bei 88% [95% KI: (87,1%; 88,5%)], unter konventioneller Beatmung bei 91% [95% KI: (90,3%; 91,2%)] und unter HFOV bei 95% [95% KI: (94,7%; 94,9%)]. Bei der Herzaktion lag während der Apnoephasen die Differenz bei 1,1 Schlägen/min (±11,3 SD) und unter HFOV bei 5,3 Schlägen/min (±26,4 SD). Unter Spontanatmung gelang es bisher nicht, eine Korrelation zwischen MBM und Referenzsignal herzustellen. Aufgrund von Interferenzproblemen war eine Erfassung der Herzaktion nur während Apnoephasen und unter HFOV möglich. Schlussfolgerung: Die Erfassung der Atemtätigkeit mittels MBM ist in einem neonatalen Tiermodell grundsätzlich möglich. Aufgrund der viel kleineren Herzsignal-anteile gelingt die Herzaktivität bisher nur in ausgewählten Situationen. Die Ergebnisse können eine Basis für die Entwicklung von wenig- bzw. nichtinvasiven Parametern in der Neonatologie sein, wobei als nächstes qualitative Eigenschaften der Atemtätigkeit erfasst werden sollten. Abstract Background: Magnetic induction measurement (MIM) allows the identification of resistance in biologic tissues by alternating magnetic fields. These occur when well-conducting (blood) and poor-conducting matter (air) is moved through the thorax during heart and lung activity. As a result, allocation of the resistance changes and the total resistance of the thorax is shifted. By using coils, these changes can be registered in a non-contact manner and recorded. To date, this measuring principle was employed only in adult volunteers or in full-grown pigs. A neonatal animal model has not yet been described. The aim of this study was to test the hypothesis that non-contact monitoring of heart and lung activity using MIM in a porcine newborn piglet model can be applied in order to evaluate neonatal disorders of heart and lung activity in the future. Materials and methods: By using five coils (three measurement and two excitation coils), placed at the bottom of an experimental incubator, magnetic induction changes, depending on the heart and lung activity in 16 analgosedated piglets, were simultaneously measured and compared with pulse oximetry and airflow detection (flow resistance and pressure differential sensor) as reference signals. In addition, spontaneous breathing, including apnea, CPAP (continuous positive airway pressure to prevent end-expiratory alveolar collapse, flow 8 l/min; pressure 5 cm H2O), mechanical ventilation (inspiratory pressure 14 cm H2O; frequency 40/min) and high frequency oxygenation ventilation (HFOV, ventilation method in lung failure) (frequency 10 Hz, mean pressure 10 cm H2O, amplitude 1.5) were performed. Lung activity with MIM compared with the reference signal was estimated with a detection rate (%) of “correct registered lung activity”. To quantify the analogy between MIM and reference signal for heart activity, the concordance correlation coefficient after Lin (95% confidence interval) and the Bland-Altman plot were calculated. Results and discussion: The detection rate for breathing [%] of MIM compared with the reference signal under CPAP was 88% [95% CI: (87.1%; 88.5%)], mechanical ventilation 91% [95% CI: (90.3%; 91.2%)] and under HFOV 95% [95% CI: (94.7%; 94.9%)]. For heart activity, during apnea the difference between MIM and reference signal was 1.1 bpm (±11.3 SD) in apnea and during HFOV 5.3 bpm (±26.4 SD). Under spontaneous breathing it was not possible to achieve a correlation. Owing to interference problems, registration of heart activity with MIM during simultaneous breathing activity (CPAP, conventional mechanical ventilation, HFOV) was insufficient. Conclusion: Non-contact monitoring of lung activity using MIM in a neonatal piglet model is possible under specific conditions. These results might be a basis for the development of non-invasive parameters in neonatology. It also provides the possibility of obtaining more information about the characteristics of lung activity of the newborn.

Healthcare worker-related MRSA cluster in a German neonatology level III ICU: a true European story.

Here we investigated a cluster of eight newly Methicillin-resistant Staphylococcus aureus (MRSA)-colonized neonates at an ICU, and present data on molecular strain characterization as well as the source identification process in which we analyze the impact of MRSA-colonized HCWs. Molecular strain characterization revealed a unique pattern which was identified as spa-type t 127--an extremely rare strain type in Germany. Environmental sampling and screening of parents of colonized neonates proved negative. However, staff screening identified one healthcare worker (HCW; 1/134) belonging to a group of recently employed Romanian HCWs who was colonized with the spa 127 strain. Subsequent screening also detected MRSA in 9/51 Romanian HCWs (18%) and 7/9 (14% of all) isolates showed the same molecular pattern as the index case (spa/PFGE type). All carriers were successfully decolonized, after which no new patient cases occurred. As a result, we have now implemented a universal screening programme of all new employees as part of our infection control management strategy. MRSA-colonized HCWs can act as a source for in hospital transmission. Since HCWs from high endemic countries are particular prone to being colonized, they may pose a risk to patients.

Staphylococcal Scalded Skin Syndrome as a Harbinger of Late-onset Staphylococcal Septicaemia in a Premature Infant of Very Low Birth Weight

Sir, Blistering skin disorders are rare conditions in neonates and infants presenting with a broad range of differential diagnoses and potentially fatal clinical sequelae. Although rarely encountered, exfoliative toxins synthesized by coagulase-positive Staphylococci must be considered as a possible underlying cause, as they are known to induce staphylococcal scalded skin syndrome (SSSS, Ritter’s disease) (1). We report here on a preterm infant who developed SSSS as presenting sign of septicaemia caused by a Staphylococcus aureus strain producing exfoliative toxins A and B.