Understanding Blood Gas Interpretation

Feasibility Analysis of ECG-Based pH Estimation for Asphyxia Detection in Neonates

Birth asphyxia is a potential cause of death that is also associated with acute and chronic morbidities. The traditional and immediate approach for monitoring birth asphyxia (i.e., arterial blood gas analysis) is highly invasive and intermittent. Additionally, alternative noninvasive approaches such as pulse oximeters can be problematic, due to the possibility of false and erroneous measurements. Therefore, further research is needed to explore alternative noninvasive and accurate monitoring methods for asphyxiated neonates. This study aims to investigate the prominent ECG features based on pH estimation that could potentially be used to explore the noninvasive, accurate, and continuous monitoring of asphyxiated neonates. The dataset used contained 274 segments of ECG and pH values recorded simultaneously. After preprocessing the data, principal component analysis and the Pan-Tompkins algorithm were used for each segment to determine the most significant ECG cycle and to compute the ECG features. Descriptive statistics were performed to describe the main properties of the processed dataset. A Kruskal-Wallis nonparametric test was then used to analyze differences between the asphyxiated and non-asphyxiated groups. Finally, a Dunn-Šidák post hoc test was used for individual comparison among the mean ranks of all groups. The findings of this study showed that ECG features (T/QRS, T Amplitude, Tslope, Tslope/T, Tslope/|T|, HR, QT, and QTc) based on pH estimation differed significantly (p < 0.05) in asphyxiated neonates. All these key ECG features were also found to be significantly different between the two groups.

Development and Characterization of Interstitial-Fluid-Mimicking Solutions for Pre-Clinical Assessment of Hypoxia

Asphyxia, a leading cause of illness and death in newborns, can be improved by early detection and management. Arterial blood gas (ABG) analysis is commonly used to diagnose and manage asphyxia, but it is invasive and carries risks. Dermal interstitial fluid (ISF) is an alternative physiological fluid that can provide valuable information about a person's health. ISF is more sensitive to severe hypoxia and metabolic disorders compared to blood, making it an attractive option for minimally invasive asphyxia detection using biosensors. However, obtaining ISF samples from humans is challenging due to ethical concerns and sampling difficulties. To address this, researchers are developing ISF-mimicking solutions as substitutes for early testing and evaluation of biosensors. This paper focuses on the development of these solutions for bench-based testing and validation of continuous asphyxia-monitoring biosensors. With an understanding of the factors influencing system quality and performance, these solutions can aid in the design of biosensors for in vivo monitoring of dermal ISF. Monitoring interstitial fluid pH levels can provide valuable insights into the severity and progression of asphyxia, aiding in accurate diagnosis and informed treatment decisions. In this study, buffer solutions were prepared to mimic the pH of ISF, and their electrical properties were analyzed. The results suggest that certain buffers can effectively mimic metabolic acidosis associated with asphyxia (pH < 7.30), while others can mimic metabolic alkalosis (pH > 7.45). Overall, this research contributes to the development of ISF-mimicking solutions and lays the groundwork for biosensor systems that monitor dermal ISF in real time.

Retrospective cohort study shows that the risks for retinopathy of prematurity included birth age and weight, medical conditions and treatment

AIM

This study described the characteristics and risk factors of neonates who developed retinopathy of prematurity (ROP) and severe treatable ROP in two Egyptian neonatal intensive care units (NICUs).

METHODS

This retrospective cohort study comprised 108 preterm neonates who were screened for ROP after being admitted to the two NICUs run by Cairo University Hospital from June 2014 to May 2015. Patients were examined using digital fundus photography and indirect ophthalmoscopy was performed if ROP was detected.

RESULTS

Retinopathy of prematurity occurred in 75 patients. Late-onset sepsis, ventilation and hypercapnia were independently associated with ROP. Patients who developed severe treatable ROP had a younger gestational age (GA) than patients who did not develop ROP or developed mild or moderate ROP (29 weeks, range 27-33 weeks versus 32 weeks, range 28-36 weeks, p = 0.002) and a lower birthweight (1200 g, range 980-1590 g versus 1460 g, range 770-2475 g, p = 0.029). The risk factors associated with severe treatable ROP included the duration of admission, the duration of incubator oxygen, late-onset sepsis, intraventricular haemorrhage, total parenteral nutrition and the duration of caffeine citrate therapy.

CONCLUSION

This study showed that the risks for ROP were wide-ranging and included GA and weight, medical conditions and treatment.

Using ABGs to optimize mechanical ventilation: three case studies illustrate how arterial blood gas analyses can guide appropriate ventilator strategy

This article focuses on translating arterial blood gas information into clinical benefits, with 3 case scenarios that focus on using arterial blood gases to manage mechanical ventilation.

Understanding neonatal ventilation: strategies for decision making in the NICU

Neonatal ventilation is an integral component of care delivered in the neonatal unit. The aim of any ventilation strategy is to support the neonate's respiratory system during compromise while limiting any long-term damage to the lungs. Understanding the principles behind neonatal ventilation is essential so that health professionals caring for sick neonates and families have the necessary knowledge to understand best practice. Given the range of existing ventilation modes and parameters available, these require explanation and clarification in the context of current evidence. Many factors can influence clinical decision making on both an individual level and within the wider perspective of neonatal care.

Arterial Blood Gases

Arterial blood gases (ABG) results reflect underlying pathology and interpretation of the results are often compounded by ongoing disease processes and clinical interventions. While ABG specimens should be analysed immediately for optimal results the Clinical and Laboratory Standards Institute (CLSI) has recommended a window of 30 minutes at room temperature from blood collection to ABG analysis. A fresh and simple approach to interpreting ABG is provided.

Reference values of capillary blood saturation in neonates and its difference from pulse oximetry

INTRODUCTION

Haemoglobin saturation is an obligatory oxygen parameter in the assessment of neonatal oxygenation. Although, pulse oximetry is currently one of the major methods in the determination of haemoglobin saturation, capillary blood saturation is still present in the diagnostic process. As well known, haemoglobin saturation value of capillary blood is insufficiently accurate, but not as much as the difference in relation to the values determined by pulse oximetry. Until now published studies have reported that capillary samples are obtained according to a protocol by the principle of free blood outflow, which is practically almost unachievable in the neonate.

OBJECTIVE

Determination of the reference values of oxygen saturation (SCO2) and partial pressure (pcO2) of capillary blood by squeezing of the foot. The determination of difference between ScO2 and pulse oximetry (SpO2).

METHODS

In 134 term newborns, we determined SpO2. Subsequently, we measured the values of ScO2 and pcO2 from the same extremity. While withdrawing a capillary sample, we exerted multiple squeezing of the foot. The mean value of ScO2, pcO2, SpO2 and the difference between ScO2 and SpO2 were determined.

RESULTS

Mean ScO2 value was 80.5 +/- 8.5%, pcO2 was 48.2 +/- 11.4 mm Hg and SpO2 was 98 +/- 1.9%. The difference between ScO2 and SpO2 values was 17.5 +/- 8.6% (t = 23.568; p = 0.000).

CONCLUSION

There is a statistically highly significant difference between the values of ScO2 and SpO2. Having the knowledge of this difference can increase the accuracy of clinical evaluation and further diagnostics. Comparison in up-to-now conducted studies suggests that the squeezing of the foot for obtaining a capillary sample in relation to free blood outflow does not bear any significant influence on the resultant values of haemoglobin saturation.