Evaluation of a Noninvasive Hemoglobin Measurement Device to Screen for Anemia in Infancy

Is noninvasive hemoglobin measurement suitable for children undergoing preoperative anesthesia consultation?

Preoperative anemia in children is a significant clinical concern requiring precise diagnosis. Although traditional blood sample collection is effective, it poses challenges because of children's aversion and technical difficulties. Therefore, this study explores the suitability of noninvasive hemoglobin measurements in children during preoperative anesthesia consultation. Noninvasive hemoglobin measurement (SpHb®; Masimo) in children aged ≤ 17 years was performed during preoperative anesthesia consultation and compared with laboratory hemoglobin (labHb) levels. SpHb was measured in 62 children (median age: 6 years, standard deviation [SD] ± 5.3) without adverse effects but was unsuccessful in one child. The bias, limits of agreement, and root mean square error between SpHb and labHb were 0.3, -2.26- +2.8, and 1.3 g/dl, respectively. LabHb demonstrated a significant regression relationship with R2 of 0.359. LabHb was associated with a negative effect on bias [- 0.443 (CI 95: - 0.591- - 0.153, P < 0.001)], i.e., SpHb tends to underestimate labHb for high labHb values. The retest reliability between two consecutive SpHb measurements was 0.727 (P < 0.001). Double measurement of SpHb, age, weight, sex, heart rate, and perfusion index had no significant effects on accuracy. Using SpHb, a specificity of 96.3% (95% confidence interval [CI 95]: 87.3%-99.5%) and a sensitivity of 57.1% (CI 95: 18.4%-90.1%) were observed. Based on adapted cut-off values for SpHb (age-dependent cut-off values plus 0.8 g/dl), a sensitivity of 100% (CI 95: 64.6%-100%) was achieved for the investigated study collective. SpHb measurement in children is a quick procedure. The accuracy of hemoglobin measurement is insufficient for the diagnosis of anemia. Thus, whether the calculated cut-off SpHb values of this study collective can be considered for anemia screening in pediatric patients undergoing preoperative anesthesia consultation should be confirmed. Trial registration number and date of registration: This prospective study was registered at ClinicalTrials.gov (NCT03586141).

Reliability of transcutaneous hemoglobin measurements in an outpatient pediatric clinic

OBJECTIVE

Our study assessed the reliability of a transcutaneous hemoglobin (tcHgb) measurement as compared to a standard capillary hemoglobin (cHgb) measurement in screening for iron deficiency anemia in a single university-based pediatric outpatient clinic.

METHODS

Study participants included all pediatric patients requiring a hemoglobin (Hgb) assessment from July 2019 to June 2020. A tcHgb measurement was attempted on all children who received a cHgb measurement. Additional variables evaluated were age, visit type, gender, insurance type, weight, BMI percentile and presence of comorbid conditions.

RESULTS

Of 777 attempts, both cHgb and tcHgb were obtained in 196 children aged 9 months to 21 years. Attempts were most successful in children > 2 years of age due to finger size and ability to remain still for one to two minutes. The mean cHgb was 12.5 ± 1.5 g/dL, mean tcHgb value 13.1 ± 2.1 g/dL, and the mean difference was 0.6 ± 2.1 g/dL (tcHgb-cHgb). An intraclass correlation coefficient was 0.29. There were no differences with regards to age, visit type, gender, insurance type, weight, BMI percentile and presence of comorbid conditions. Bland-Altman analysis displayed a lack of agreement between the tcHgb and cHgb measurements and tcHgb tended to over-estimate Hgb values when the cHgb was low.

CONCLUSIONS

The measurement of a transcutaneous Hgb is less invasive for pediatric patients but has significant limitations. Smaller children (probe specifications) and movement limited the ability to obtain a tcHgb measurement in ~75% of children tested. Falsely normal tcHgb values occurred due to overestimation of hemoglobin when compared to the traditional cHgb device. The suboptimal sensitivity of the tcHgb device may cause providers to miss a diagnosis of anemia. Future research should compare both methods of Hgb assessment to the gold standard laboratory-analyzed complete blood count and use a smaller probe for children under 2, once available.

Emerging point-of-care technologies for anemia detection

Anemia, characterized by low blood hemoglobin level, affects about 25% of the world's population with the heaviest burden borne by women and children. Anemia leads to impaired cognitive development in children, as well as high morbidity and early mortality among sufferers. Anemia can be caused by nutritional deficiencies, oncologic treatments and diseases, and infections such as malaria, as well as inherited hemoglobin or red cell disorders. Effective treatments are available for anemia upon early detection and the treatment method is highly dependent on the cause of anemia. There is a need for point-of-care (POC) screening, early diagnosis, and monitoring of anemia, which is currently not widely accessible due to technical challenges and cost, especially in low- and middle-income countries where anemia is most prevalent. This review first introduces the evolution of anemia detection methods followed by their implementation in current commercially available POC anemia diagnostic devices. Then, emerging POC anemia detection technologies leveraging new methods are reviewed. Finally, we highlight the future trends of integrating anemia detection with the diagnosis of relevant underlying disorders to accurately identify specific root causes and to facilitate personalized treatment and care.

Invasive and non-invasive point-of-care testing and point-of-care monitoring of the hemoglobin concentration in human blood – how accurate are the data?

In this review, scientific investigations of point-of-care testing (POCT) and point-of-care monitoring (POCM) devices are summarized with regard to the measurement accuracy of the hemoglobin concentration. As a common basis, information according to the Bland and Altman principle [bias, limits of agreement (LOA)] as well as the measurement accuracy and precision are considered, so that the comparability can be mapped. These collected data are subdivided according to the manufacturers, devices and procedures (invasive and non-invasive). A total of 31 devices were identified. A comparability of the scientific investigations in particular was given for 23 devices (18 invasive and five non-invasive measuring devices). In terms of measurement accuracy, there is a clear leap between invasive and non-invasive procedures, while no discernible improvement can be derived in the considered time frame from 2010 to 2018. According to the intended use, strict specifications result from the clinical standards, which are insufficiently met by the systems. More stringent requirements can be derived both in the area of blood donation and in the treatment of patients.

A Pilot Randomized Controlled Trial of a New Supplementary Food Designed to Enhance Cognitive Performance during Prevention and Treatment of Malnutrition in Childhood

BACKGROUND

Cognitive impairment associated with childhood malnutrition and stunting is generally considered irreversible.

OBJECTIVE

The aim was to test a new nutritional supplement for the prevention and treatment of moderate-acute malnutrition (MAM) focused on enhancing cognitive performance.

METHODS

An 11-wk, village-randomized, controlled pilot trial was conducted in 78 children aged 1-3 or 5-7 y living in villages in Guinea-Bissau. The supplement contained 291 kcal/d for young children and 350 kcal/d for older children and included 5 nutrients and 2 flavan-3-ol-rich ingredients not present in current food-based recommendations for MAM. Local bakers prepared the supplement from a combination of locally sourced items and an imported mix of ingredients, and it was administered by community health workers 5 d/wk. The primary outcome was executive function abilities at 11 wk. Secondary outcomes included additional cognitive measures and changes in z scores for weight (weight-for-age) and height (height-for-age) and hemoglobin concentrations at 11 wk. An index of cerebral blood flow (CBF) was also measured at 11 wk to explore the use of this measurement as a biological index of cognitive impairment.

RESULTS

There were no significant differences in any outcome between groups at baseline. There was a beneficial effect of random assignment to the supplement group on working memory at 11 wk in children aged 1-3 y (P < 0.05). This difference contrasted with no effect in older children and was not associated with faster growth rate. In addition, CBF correlated with task-switching performance (P < 0.05).

CONCLUSIONS

These preliminary data suggest that cognitive impairment can be monitored with measurement of CBF. In addition, the findings provide preliminary data that suggest that it may be possible to improve poor cognitive performance in young children through changes in the nutritional formulation of supplementary foods used to prevent and treat MAM. Powered studies of the new supplement formulation are needed. This trial was registered at clinicaltrials.gov as NCT03017209.

Accuracy of Capillary Hemoglobin Measurements for the Detection of Anemia among U.S. Low-Income Toddlers and Pregnant Women

The aim of this study is to evaluate the accuracy of capillary hemoglobin (Hb) measurements in detecting anemia among low-income toddlers (aged 12–35 months) and pregnant women. In analyses of data among toddlers from Kansas City (n = 402) and St. Louis, Missouri (n = 236), and pregnant women at <20 weeks gestation from Cleveland, Ohio (n = 397), we compared subjects’ anemia status based on capillary Hb concentrations in finger puncture samples as measured by the HemoCue system with their anemia status based on venous Hb concentrations as measured by the HemoCue and Coulter Counter. The sensitivity of capillary blood analyses in identifying cases of anemia was 32.8% (95% Confidence Intervals (CI): 21.0%–46.3%), among Kansas City toddlers, 59.7% (95% CI: 45.8%–72.4%) among St. Louis toddlers, and 66.7% (95% CI: 46.0%–83.5%) among pregnant women in Cleveland; the corresponding specificities were 97.7%, 86.6%, and 96.7%, respectively. The correlation between HemoCue and Coulter Counter measurements of venous Hb (0.9) was higher than that between HemoCue measurements of capillary and venous blood (0.8). The results show that Hb measurements of capillary blood with HemoCue were not optimal for determining the anemia status of toddlers and pregnant women.

Poor Validity of Noninvasive Hemoglobin Measurements by Pulse Oximetry Compared with Conventional Absorptiometry in Children in Côte d'Ivoire

Anemia remains a major public health issue in many African communities. We compared a novel, commercially available noninvasive hemoglobin (Hb)-measuring device to direct Hb measurements by finger-prick samples in a pediatric cohort in rural Côte d'Ivoire. Noninvasive Hb measurements were attempted in 191 children 2-15 years of age and obtained in 102 (53.5%) children. The median Hb for the 102 children was 12.0 g/dL (interquartile range [IQR] = 11.3-12.7 g/dL) for conventional absorptiometry and 13.3 g/dL (IQR = 12.1-14.2 g/dL) for noninvasive measurements. A Bland-Altman analysis demonstrated a median bias of +1.1 g/dL (IQR = 0.4-2.0 g/dL), with greater overestimation of Hb by noninvasive testing occurring at low Hb values. This overestimation of the noninvasive Hb-measuring device to direct Hb measurements persisted across preschool- and school-aged children, and both sexes. The Pearson correlation coefficient was 0.50 for children 4-9 years of age, and 0.33 for children 10-15 years of age. Further study and development of noninvasive Hb devices is necessary prior to implementation in African pediatric populations.