[Comment on article "Variability of hemoglobin and hematocrit determined in blood gas equipment"]. / Comentario al artículo "Variabilidad de la hemoglobina y hematocrito determinados en equipo de gases sanguíneos".

´The analysis of samples on different equipment may lead to variation between results; in the article "Variability of hemoglobin and hematocrit determined in blood gas equipment", the authors talk about the variability of hemoglobin and hematocrit between an automated hematology analyzer and an arterial blood gas analyzer. Information is requested on some aspects considered relevant to improve the understanding of the conclusions.

El análisis de muestras en diferentes equipos puede conllevar una variación entre los resultados; en el artículo "Variabilidad de la hemoglobina y hematocrito determinados en equipo de gases sanguíneos", sus autores hablan de la variabilidad de hemoglobina y hematocrito entre un analizador automatizado de hematología y un analizador de gases arteriales. Se solicita información sobre algunos aspectos considerados relevantes para mejorar la compresión de las conclusiones.

Arterial blood gas as a prognostic indicator in patients with sepsis.

Abnormal arterial blood gas (ABG) among patients with sepsis is an important prognostic indicator. All-cause mortality was the highest among patients with respiratory acidosis (4/9 = 44.4%), followed by those having metabolic acidosis (3/8 = 37.5%). Median length of hospital and intensive care unit stay was 15.75 days and 6.25 days for those with abnormal ABG and 11 and 3.5 days among those with normal ABG. Median health-care expenditure at the time of discharge or death of the patient was the highest in patients with respiratory acidosis ($14,473) and least in patients with normal ABG ($3,384) (average expenditure among patients with abnormal ABG was [$10,059]).

Determining the predictive capability of a Clinical Assessment Scoring Chart to differentiate severity of the clinical consequences of neonatal calf diarrhea relative to gold-standard blood gas analysis.

Neonatal calf diarrhea (NCD) is a major problem to calf health worldwide, in terms of both morbidity and mortality. A five-point ordinal scale clinical assessment scoring (CAS) chart was utilized to assess calves suffering from NCD-related clinical abnormalities (acidosis and dehydration) on commercial farms. The objective of this research was to determine the predictive capability of this CAS chart against gold standard blood gas parameters, designed to assist farmers in the accurate assessment of the clinical consequences of NCD. A total of 443 diarrheic and non-diarrheic calves were enrolled in the study. The CAS chart rated a calf's health from no clinical signs to varying degrees of clinical severity on a 0 (clinically normal) to 4 (grave) scale, based on clinical indicators including calf demeanour, ear position, mobility, suckle reflex, desire-to-feed, and enophthalmos. Blood gas analysis was conducted for individual calves, consisting of pH, base excess, Na+, K+, Ca2+, Cl-, glucose, total hemoglobin, bicarbonate, anion gap, and strong ion difference. Statistical evaluation was performed by comparison of the CAS score with blood gas profiles using ordinal logistic regression and a non-parametric estimation of the Receiver Operating Characteristics (ROC). The ROC analysis indicated that the CAS chart had acceptable specificity (>95%) with low sensitivity (<60%) in differentiating clinically normal from acidotic/dehydrated cases. Assessment of individual severity classes indicated that the chart can predict and differentiate both clinically normal and advanced cases from the other severity classes (peak estimations >80%) but had reduced accuracy in differentiating mild and moderate cases (peak estimations >50%). The chart, as presented, provides a simple tool to differentiate clinically normal from calves suffering the consequences of diarrhea, but fails to accurately differentiate severity for NCD related acidosis and dehydration. Further efforts are required to enhance the sensitivity and differential diagnostic value of this type of chart.

Arterial blood gas analysis utility in predicting lung injury in blunt chest trauma.

BACKGROUND: thoracic trauma is one of the leading causes of death in all age groups and accounts for 25-50 % of all traumatic injuries. With the term lung injury in blunt chest trauma, we identified a spectrum of conditions: lung contusion, pneumothorax and haemothorax. The aim of this study was to evaluate the utility of arterial blood gas analysis parameters in predicting lung injury in blunt chest trauma. METHODS: we included 51 patients presenting to the Emergency Department of "C.T.O." Hospital in Naples [Italy] for blunt chest trauma. The patients were assigned to the Lung Injury Group or to the Non-Lung Injury Group basing on CT scan findings. For each patient, we calculated the alveolar-arterial oxygen gradient [AaDO2], the AaDO2 augmentation, the arterial partial pressure of oxygen deficit [PaO2 Deficit] and the ratio between arterial partial pressure of oxygen and fraction of inspired oxygen [P/F]. Areas under the curve [AUC] and receiver operating characteristic [ROC] curve were used to compare the performance of each different test in relation to the detection of lung injury in blunt chest trauma. RESULTS: patients with lung injury had lower oxygen saturation, arterial partial pressure of oxygen, P/F and higher PaO2 Deficit, AaDO2, AaDO2 augmentation than patients without lung injury. PaO2 Deficit, AaDO2 and AaDO2 augmentation showed a good accuracy to predict lung injury in blunt chest trauma. CONCLUSION: our study demonstrates that the combination of different arterial blood gas analysis variables may be a fast approach for identifying patients with lung injury in the setting of blunt chest trauma in the Emergency Department.

Continuous Noninvasive Carbon Dioxide Monitoring in Neonates: From Theory to Standard of Care.

Ventilatory support may affect the short- and long-term neurologic and respiratory morbidities of preterm infants. Ongoing monitoring of oxygenation and ventilation and control of adequate levels of oxygen, pressures, and volumes can decrease the incidence of such adverse outcomes. Use of pulse oximetry became a standard of care for titrating oxygen delivery, but continuous noninvasive monitoring of carbon dioxide (CO2) is not routinely used in NICUs. Continuous monitoring of CO2 level may be crucial because hypocarbia and hypercarbia in extremely preterm infants are associated with lung and brain morbidities, specifically bronchopulmonary dysplasia, intraventricular hemorrhage, and cystic periventricular leukomalacia. It is shown that continuous monitoring of CO2 levels helps in maintaining stable CO2 values within an accepted target range. Continuous monitoring of CO2 levels can be used in the delivery room, during transport, and in infants receiving invasive or noninvasive respiratory support in the NICU. It is logical to hypothesize that this will result in better outcome for extremely preterm infants. In this article, we review the different noninvasive CO2 monitoring alternatives and devices, their advantages and disadvantages, and the available clinical data supporting or negating their use as a standard of care in NICUs.

Can the blood gas analyser results be believed? A prospective multicentre study comparing haemoglobin, sodium and potassium measurements by blood gas analysers and laboratory auto-analysers.

Blood gas analysers are point-of-care testing devices used in the management of critically ill patients. Controversy remains over the agreement between the results obtained from blood gas analysers and laboratory auto-analysers for haematological and biochemistry parameters. We conducted a prospective analytical observational study in five intensive care units in Western Australia, in patients who had a full blood count (FBC), urea, electrolytes and creatinine (UEC), and a blood gas performed within 1 h of each other during the first 24 h of their intensive care unit admission. The main outcome measure was to determine the agreement in haemoglobin, sodium, and potassium results between laboratory haematology and biochemistry auto-analysers and blood gas analysers. A total of 219 paired tests were available for haemoglobin and sodium, and 215 for potassium. There was no statistically significant difference between the results of the blood gas and laboratory auto-analysers for haemoglobin (mean difference -0.35 g/L, 95% confidence interval (CI) -1.20 to 0.51, P = 0.425). Although the mean differences between the two methods were statistically significant for sodium (mean difference 1.49 mmol/L, 95% CI 1.23-1.76, P < 0.0001) and potassium (mean difference 0.19 mmol/L, 95% CI 0.15-0.24, P < 0.0001), the mean biases on the Bland-Altman plots were small and independent of the magnitude of the measurements. The two methods of measurement for haemoglobin, sodium and potassium agreed with each other under most clinical situations when their values were within or close to normal range suggesting that routine concurrent blood gas and formal laboratory testing for haemoglobin, sodium and potassium concentrations in the intensive care unit is unwarranted.

Continuous Monitoring of pH and Blood Gases Using Ion-Sensitive and Gas-Sensitive Field Effect Transistors Operating in the Amperometric Mode in Presence of Drift.

Accurate and cost-effective integrated sensor systems for continuous monitoring of pH and blood gases continue to be in high demand. The capacity of ion-selective and Gas-sensitive field effect transistors (FETs) to serve as low-power sensors for accurate continuous monitoring of pH and blood gases is evaluated in the amperometric or current mode of operation. A stand-alone current-mode topology is employed in which a constant bias is applied to the gate with the drain current serving as the measuring signal. Compared with voltage-mode operation (e.g., in the feedback mode in ion-selective FETs), current-mode topologies offer the advantages of small size and low power consumption. However, the ion-selective FET (ISFET) and the Gas-sensitive FET (GasFET) exhibit a similar drift behavior, imposing a serious limitation on the accuracy of these sensors for continuous monitoring applications irrespective of the mode of operation. Given the slow temporal variation associated with the drift characteristics in both devices, a common post-processing technique that involves monitoring the variation of the drain current over short intervals of time can potentially allow extraction of the measuring signal in presence of drift in both sensor types. Furthermore, in the amperometric mode the static sensitivity of a FET-based sensor, given by the product of the FET transconductance and the sensitivity of the device threshold voltage to the measurand concentration, can be increased by adjusting the device design parameters. Increasing the sensitivity, while of interest in its own right, also enhances the accuracy of the proposed method. Rigorous analytical validation of the method is presented for GasFET operation in the amperometric mode. Moreover, the correction algorithm is verified experimentally using a Si3N4-gate ISFET operating in the amperometric mode to monitor pH variations ranging from 3.5 to 10.

Correlation between sodium, potassium, hemoglobin, hematocrit, and glucose values as measured by a laboratory autoanalyzer and a blood gas analyzer.

INTRODUCTION: Blood gas analyzers can be alternatives to laboratory autoanalyzers for obtaining test results in just a few minutes. We aimed to find out whether the results from blood gas analyzers are reliable when compared to results of core laboratory autoanalyzers. MATERIALS AND METHODS: This retrospective, single-centered study examined the electronic records of patients admitted to the emergency department of a tertiary care teaching hospital between May 2014 and December 2017. Excluded from the study were patients under 18 years old, those lacking data, those who had any treatment before the laboratory tests, those whose venous gas results were reported more than 30 minutes after the blood sample was taken and for whom any of the laboratory tests were performed at a different time, and recurrent laboratory results from a single patient. RESULTS: Laboratory results were analyzed from a total of 31,060 patients. The correlation coefficients for sodium, potassium, hemoglobin, hematocrit, and glucose levels measured by a blood gas analyzer and a laboratory autoanalyzer were 0.725, 0.593, 0.982, 0.958, and 0.984, respectively; however, there were no good, acceptable agreement limits for any of the parameters. In addition, these results did not change according to the different pH stages (acidosis, normal pH and alkalosis). CONCLUSION: The two types of measurements showed a moderate correlation for sodium and potassium levels and a strong correlation for glucose, hemoglobin, and hematocrit levels, but none of the levels had acceptable agreement limits. Clinicians should be aware of the limitations of blood gas analyzer results.

Una mirada crítica a las consideraciones preanalíticas de gases sanguíneos / Uma análise crítica das considerações pré-analíticas dos gases sangüíneos / A critical look at the preanalytical considerations of blood gases

Introducción: uno de los asuntos menos discutidos y que poco se entiende del mismo, es la seguridad del paciente. Hace poco tiempo se ha convertido en un tema ubicuo y polémico, especialmente para algunas organizaciones médicas. Objetivo: sistematizar referentes teóricos relacionados con las particularidades del proceso de toma de muestra y análisis de los gases en sangre. Método: se revisan los principales elementos que gravitan en esta fase para el análisis de los gases sanguíneos, así como la influencia que estos pueden tener en la calidad de los resultados y las prácticas clínicas y de laboratorio para optimizarla. Desarrollo: la fase preanalítica es aquella que antecede a la realización de un ensayo o estudio de laboratorio e incluye la preparación del paciente, la confección de la solicitud de análisis y los cuidados para la obtención de las muestras. La atención que el médico de asistencia y el personal del laboratorio concedan a esta fase es directamente proporcional a la calidad de los resultados que se obtendrán. Conclusiones: el análisis de pH y gases sanguíneos deben ser considerados siempre como un estudio de urgencia. La muestra no debe permanecer por más de diez minutos a temperatura ambiente y cuando el análisis demore más de 15 minutos, la muestra deberá ser conservada en agua con hielo(AU)

Introduction: one of the least discussed issues and that little is understood about it, is patient safety. It has recently become a ubiquitous and controversial issue, especially for some medical organizations. Objective: to systematize theoretical references related to the particularities of the process of sample taking and analysis of blood gases. Method: the main elements that gravitate in this phase are analyzed for the blood gas analysis, as well as the influence that these can have on the quality of the results and the clinical and laboratory practices to optimize it. Development: the preanalytical phase is the one that precedes the performance of a trial or laboratory study and includes the preparation of the patient, the preparation of the analysis request and the care for obtaining the samples. The attention that the attending physician and laboratory staff give to this phase is directly proportional to the quality of the results that will be obtained. Conclusions: the analysis of pH and blood gases should always be considered as an emergency study. The sample should not remain for more than ten minutes at room temperature and when the analysis takes more than 15 minutes, the sample should be stored in ice water(au)

Introdução: uma das questões menos discutidas e que pouco é entendido sobre isso, é a segurança do paciente. Tornou-se recentemente uma questão onipresente e controversa, especialmente para algumas organizações médicas. Objetivo: sistematizar referenciais teóricos relacionados às particularidades do processo de coleta de amostras e análise de gases sangüíneos. Método: os principais elementos que gravitam nesta fase são analisados para a gasometria, assim como a influência que estes podem ter na qualidade dos resultados e nas práticas clínicas e laboratoriais para otimizá-la. Desenvolvimento: a fase pré-analítica é aquela que precede a realização de uma pesquisa ou estudo laboratorial e inclui a preparação do paciente, a elaboração do pedido de análise e o cuidado para obtenção das amostras. A atenção que o médico assistente e o pessoal de laboratório dão a essa fase é diretamente proporcional à qualidade dos resultados que serão obtidos. Conclusões: a análise do pH e dos gases sanguíneos deve ser sempre considerada como um estudo de emergência. A amostra não deve permanecer por mais de dez minutos em temperatura ambiente e quando a análise demora mais de 15 minutos, a amostra deve ser armazenada em água gelada(AU)

The discriminative value of blood gas analysis parameters in the differential diagnosis of transient disorders of consciousness.

AIM: The differentiation between epileptic and non-epileptic episodes can be challenging. Our aim was to compare lactate, anion gap (AG), bicarbonate and the Denver Seizure Score (DSS) as point-of-care test (POCT) markers for episodes of transient alterations of consciousness. METHODS: The blood serum parameters were drawn at arrival in the emergency department (ED) within 2 h of the episode. After calculating AG and DSS values, the four parameters were compared retrospectively between patients with generalized tonic-clonic seizures (GTCS) (n = 165) and patients with other disorders of consciousness [syncopes (n = 43), and psychogenic non-epileptic seizures (n = 15)]. Additionally, we compared all values among men and women. RESULTS: In GTCS patients, all four parameters differed significantly compared to non-epileptic episode patients (p < 0.001). Serum lactate showed significant additional benefit over the remaining values, with an AUC of 0.947 (95% CI 0.92-0.975) and a high sensitivity and specificity for an optimal cut-off value of 2.45 mmol/l. For DSS, the AUC was 0.857 (95% CI 0.808-0.906; cut-off: 0.35), and for AG 0.836 (95% CI 0.783-0.889; cut-off: 12.45 mmol/l). In the case of serum bicarbonate, the AUC was 0.831 (95% CI 0.775-0.886; cut-off: 22.75 mmol/l). In the sex-dependent comparison, the results were similar. Men showed more significant differences in the compared values than women. CONCLUSIONS: Serum lactate is best suited as POCT marker in the differential diagnosis of epileptic and non-epileptic episodes and is superior to AG, DSS and bicarbonate. The differences among sexes may pose a challenge in their implementation and interpretation.

Establishing and Evaluating Autoverification Rules with Intelligent Guidelines for Arterial Blood Gas Analysis in a Clinical Laboratory.

Arterial blood gas (ABG) analysis is important for acutely ill patients and should be performed by qualified laboratorians. The existing manual verifications are tedious, time-consuming, and prone to send wrong reports. Autoverification uses computer-based rules to verify clinical laboratory test results without manual review. To date, no data are available on the use of autoverification for ABG analysis. All autoverification rules were established according to AUTO10-A. Additionally, the rules were established using retrospective patient data, and then validated by actual clinical samples in a "live" environment before go-live. The average autoverification passing rate was 75.5%. The turnaround time (TAT) was reduced by 33.3% (27 min vs 18 min). Moreover, the error rate fell to 0.05% after implementation. Statistical analysis resulted in a kappa statistic of 0.92 ( p < 0.01), indicating close agreement between autoverification and senior technician verification, and the chi-square value was 22.4 ( p < 0.01), indicating that the autoverification error rate was lower than the manual verification error rate. Results showed that implementing autoverification rules with intelligent guidelines for ABG analysis of patients with critical illnesses could decrease the number of samples requiring manual verification, reduce TAT, and eliminate errors, allowing laboratorians to concentrate more time on abnormal samples, patient care, and collaboration with physicians.

National surveys on internal quality control for blood gas analysis and related electrolytes in clinical laboratories of China.

BACKGROUND: Internal quality control (IQC) is essential for precision evaluation and continuous quality improvement. This study aims to investigate the IQC status of blood gas analysis (BGA) in clinical laboratories of China from 2014 to 2017. METHODS: IQC information on BGA (including pH, pCO2, pO2, Na+, K+, Ca2+, Cl-) was submitted by external quality assessment (EQA) participant laboratories and collected through Clinet-EQA reporting system in March from 2014 to 2017. First, current CVs were compared among different years and measurement systems. Then, percentages of laboratories meeting five allowable imprecision specifications for each analyte were calculated, respectively. Finally, laboratories were divided into different groups based on control rules and frequency to compare their variation trend. RESULTS: The current CVs of BGA were significantly decreasing from 2014 to 2017. pH and pCO2 got the highest pass rates when compared with the minimum imprecision specification, whereas pO2, Na+, K+, Ca2+, Cl- got the highest pass rates when 1/3 TEa imprecision specification applied. The pass rates of pH, pO2, Na+, K+, Ca2+, Cl- were significantly increasing during the 4 years. The comparisons of current CVs among different measurement systems showed that the precision performance of different analytes among different measurement systems had no regular distribution from 2014 to 2017. The analysis of IQC practice indicated great progress and improvement among different years. CONCLUSIONS: The imprecision performance of BGA has improved from 2014 to 2017, but the status of imprecision performance in China remains unsatisfying. Therefore, further investigation and continuous improvement measures should be taken.

Determination of reference intervals and comparison of venous blood gas parameters using a standard and nonstandard collection method in 51 dogs.

INTRODUCTION: The aim of this study was to determine reference intervals (RI) for venous blood parameters determined with the RAPIDPoint 500 (RP500) blood gas analyzer using blood gas syringes (BGS) and to determine whether immediate analysis of venous blood collected into lithium heparin (LH) tubes can replace anaerobic blood sampling into BGS. The null hypothesis was that canine venous blood samples collected in BGS and in LH tubes are comparable. Jugular blood was collected from 51 healthy dogs into a BGS and a LH tube. The BGS was immediately analyzed followed by the LH tube. The RI were calculated from BGS results. The BGS and LH tubes results were compared using paired t-test or Wilcoxon matched-pairs signed-rank test and Bland-Altman analysis. To assess clinical relevance, the bias between BGS and LH tubes was compared with the allowable total error (TEa). Values derived from LH tubes showed no significant difference for standard bicarbonate (HCO3std), whole blood base excess (BE B), Na, K, Cl, glucose and hemoglobin (tHb). The pH, partial pressure of carbon dioxide and oxygen, actual bicarbonate, extracellular base excess, ionized Ca, anion gap and lactate were significantly (p.

INTRODUCTION: Le but de la présente étude était de déterminer l'intervalle de référence (RI) de l'analyseur de gaz du sang RAPIDPoint 500 (RP500) pour du sang veineux prélevé dans des seringues pour gaz du sang (BGS) ainsi que de voir si une analyse immédiate du sang collecté dans des tubes à l'héparine de lithium (LH) pouvait remplacer la collecte anaérobe dans des seringues BGS. L'hypothèse était que les échantillons sanguins dans les seringues BGS et dans les tubes LH sont comparables. On a prélevé du sang de la veine jugulaire sur BGS et LH chez 51 chiens en bonne santé, on l'a analysé immédiatement avec l'analyseur RP500 et on a calculé les intervalles de référence pour les résultats des prélèvements sur BGS. Les résultats des prélèvements sur BGS et sur LH ont été comparés au moyen de t-test appariés ou d'un test de Wilcoxon signé ainsi que par une analyse de Bland-Altman. Pour juger de la signification clinique, on a comparé le biais entre BGS et LH avec une erreur globale admissible (TEa). Il n'y avait pas de différence significative entre BGS et LH en ce qui concerne le bicarbonate standard, l'excès basique du sang total, le sodium, le potassium, le glucose et l'hémoglobine. Le pH, les pressions partielles de gaz carbonique et d'oxygène, le bicarbonate effectif, l'excès basique extracellulaire, le calcium ionisé, le trou anionique et le lactate étaient significativement (p.

Blood Gas Analyzer Accuracy of Glucose Measurements.

OBJECTIVE: To investigate the comparability of glucose levels measured with blood gas analyzers (BGAs) and by central laboratories (CLs). MATERIAL AND METHODS: Glucose measurements obtained between June 1, 2007, and March 1, 2016, at the Vanderbilt University Medical Center were reviewed. The agreement between CL and BGA results were assessed using Bland-Altman, consensus error grid (CEG), and surveillance error grid (SEG) analyses. We further analyzed the BGAs' performance against the US Food and Drug Administration (FDA) 2014 draft guidance and 2016 final guidance for blood glucose monitoring and the International Organization for Standardization (ISO) 15197:2013 standard. RESULTS: We analyzed 2671 paired glucose measurements, including 50 pairs of hypoglycemic values (1.9%). Bland-Altman analysis yielded a mean bias of -3.1 mg/dL, with 98.1% of paired values meeting the 95% limits of agreement. In the hypoglycemic range, the mean bias was -0.8 mg/dL, with 100% of paired values meeting the 95% limits of agreement. When using CEG analysis, 99.9% of the paired values fell within the no risk zone. Similar results were found using SEG analysis. For the FDA 2014 draft guidance, our data did not meet the target compliance rate. For the FDA 2016 final guidance, our data partially met the target compliance rate. For the ISO standard, our data met the target compliance rate. CONCLUSION: In this study, the agreement for glucose measurement between common BGAs and CL instruments met the ISO 2013 standard. However, BGA accuracy did not meet the stricter requirements of the FDA 2014 draft guidance or 2016 final guidance. Fortunately, plotting these results on either the CEG or the SEG revealed no results in either the great or extreme clinical risk zones.

Impaired clinical utility of sequential patient GEM blood gas measurements associated with calibration schedule.

BACKGROUND: Within- and/or between-instrument variation may falsely indicate patient trends or obscure real trends. We employ a methodology that transforms sequential intra-patient results into estimates of biologic and analytic variation. We previously derived realistic biologic variation (sb) of blood gas (BG) and hematology analytes. We extend this methodology to derive the imprecision of two GEM 4000 BG analyzers. METHODS: A laboratory data repository provided arterial BG, electrolyte and metabolite results generated by two GEM 4000s on ICU patients in 2012-2013. We tabulated consecutive pairs of intra-patient results separated by increasing time interval between consecutive tests. The average between pair variations were regressed against time with the y-intercept representing the sum of the biologic variation and short term analytic variation: yo2=sb2+sa2. Using an equivalent equation for the Radiometer ABL, the imprecision of the two GEMs was calculated: saGEM=(yoGEM2-yoABL2+saABL2)1/2. This analysis was performed for nearly all measurements, regardless of time as well for values obtained over two 12h mutually exclusive periods, starting either at 2am or 2pm. RESULTS: Regression graphs were derived from 1800 patients' blood gas results with least 10,000 data pairs grouped into 2h intervals. The calculated saGEM exceed the directly measured saABL with many GEM sigma ratios of biologic variation/analytic variation being close to unity. All of the afternoon saGEM exceeded their morning counterparts with pH, pCO2, K and bicarbonate being statistically significant. CONCLUSION: For many analytes, the average analytical variation of tandem GEMs approximates the biologic variation, indicating impaired clinical usefulness of tandem sequential measurements. A significant component of this variation is due to increased variation of the GEMs between 2pm and 2am.

Stability of ionized calcium measurements at concentrations less than 0.3 mmol/L by point-of-care blood gas instruments: application for postfilter calcium quality control in patients with citrate anticoagulation during extracorporeal circulation.

Background Measurements of ionized calcium (Ca2+) at concentrations less than 0.3 mmol/L are required for postfilter control in patients who receive extracorporeal circulation with sodium citrate anticoagulation. This study evaluates the stability of the Ca2+ measurements at such concentrations. Methods The stability of the Ca2+ measurements was tested by measuring daily the external standard Qualicheck concentration 3 s7950, Radiometer (0.22-0.25 mmol/L) by blood gas instruments ABL800 and ABL90, Radiometer. Two different Ca2+ membrane lots were tested for the usual membrane lifetime of 12 weeks at ABL800 instruments. For the ABL90 instrument, the sensor cassette (with Ca2+ membrane and electrode) was replaced after four weeks as required. Results We observed over 40% Ca2+ increase within the usual 12 weeks lifetime of the Ca2+ membrane at the ABL800 instruments. Measurements of Ca2+ at concentrations less than 0.3 mmol/L were within acceptable limits for both ABL800 and ABL90 instruments when Ca2+ membrane and sensor cassette were replaced after four weeks. Conclusions For ABL800 instruments, it is necessary to use an extra quality control (<0.3 mmol/L) in addition to the usual quality controls to monitor Ca2+ measurements below 0.3 mmol/L. The acceptable stability of the Ca2+ measurements can be achieved by the Ca2+ membrane and sensor cassette replacement after four weeks. If the usual 12 weeks of Ca2+ membrane lifetime is maintained, it may result in a clinically significant overestimation of Ca2+ by ABL800 instruments.

[The practice of neonatal umbilical blood gas analysis in the "Alsace" regional French perinatal network]. / La pratique de l'analyse des gaz du sang au cordon ombilical dans le réseau périnatal alsacien.

OBJECTIVE: The assessment of neonatal well-being is paramount in delivery rooms. For that purpose, it is recommended in France to carry out a systematic neonatal umbilical cord blood gas analysis. The aim of this study is to evaluate how umbilical cord blood gas sampling is realised, analysed and interpreted by midwives in a French regional perinatal network. MATERIALS AND METHODS: We conducted a survey focused on randomly selected midwives partitioning in different maternities that constitute the "Alsace" regional perinatal network. A questionnaire concerning the modalities of umbilical cord blood sampling, its analysis and the interpretation of results was used during interviews with included midwives. RESULTS: Fifty-one midwives were included in the study (15.8% of whom were working in delivery rooms). Only 13% of maternities constituting the perinatal network did not realise systematic neonatal umbilical cord blood analysis. Among interviewed midwives, 78.4% reported umbilical cord clamping after the first breath of the child. Among the midwives included, 86.3% of them realise sampling from the umbilical artery and 29.4% from both umbilical artery and vein. For 86.3% of interviewed midwives, the leitmotif of realising umbilical blood sampling was medico-legal. More than two third of included midwives interpret blood gas taking into account two parameters (either pH and base excess, or lactate). They settled at 7.0-7.2, the limit below which a newborn might present sequelae. DISCUSSION AND CONCLUSION: This study shows that the neonatal umbilical cord blood gas analysis at birth is almost systematic in this regional French perinatal network. It is realised primarily for medico-legal purpose. However, there are significant variations in sampling procedures and interpretation. This should lead to the establishment within each maternity of a neonatal umbilical cord blood gas sampling protocol along with a midwifery training program.

[Setting up of 15 POC blood gas analyzers at Montpellier Hosptital (France)]. / Mise en place de 15 analyseurs de gaz du sang délocalisés GEM(®) Premier™ 4000 (IL) au CHU de Montpellier - Partage d'expérience.

The purpose of this article is to describe the setting up of 15 blood gas analyzers GEM(®) Premier™ 4000 (IL) at Montpellier hospital. This experience includes analytical characterization (within and between run coefficient of variation) using GSE and GHE IL controls, correlation of 35 samples with a routinely used laboratory blood gas analyzer (Cobas b221, Roche(®)). We shall also develop the training, the habilitation and its follow-up for the user staff (450 people) of the different hospital's units in the aim of the accreditation.

Robustness of arterial blood gas analysis for assessment of respiratory safety pharmacology in rats.

Whole body plethysmography using unrestrained animals is a common technique for assessing the respiratory risk of new drugs in safety pharmacology studies in rats. However, wide variations in experimental technique make cross laboratory comparison of data difficult and raise concerns that non-appropriate conditions may mask the deleterious effects of test compounds - in particular with suspected respiratory depressants. Therefore, the objective of this study was to evaluate the robustness of arterial blood gas analysis as an alternative to plethysmography in rats. We sought to do this by assessing the effect of different vehicles and times post-surgical catheterization on blood gas measurements, in addition to determining sensitivity to multiple opioids. Furthermore, we determined intra-lab variability from multiple datasets utilizing morphine and generated within a single lab and lastly, inter-lab variability was measured by comparing datasets generated in two separate labs. Overall, our data show that arterial blood gas analysis is a measure that is both flexible in terms of experimental conditions and highly sensitive to respiratory depressants, two key limitations when using plethysmography. As such, our data strongly advocate the adoption of arterial blood gas analysis as an investigative approach to reliably examine the respiratory depressant effects of opioids.