Blood Gas Laboratory Research Articles

EVALUATION OF BLOOD GAS INSTRUMENTS WITH 6 SIGMA METHODOLOGY

Purpose : 6 sigma is one of the most effective quality tools for demonstrating laboratory analytical performance. 6 sigma tells us what level we are at and what rules to follow in case of poor performance. Blood gas analysis plays an important role in the assessment of critical illness, determining the aetiology and severity of disease. In our study, we aimed to evaluate the test performance of blood gas instruments in our hospital with 6 sigma methodology. Methods : The study included pH, pO2, pCO2, glucose, lactate, ionised Ca, Na, K and Cl parameters analysed on Siemens RAPIDpoint 500e blood gas instruments in the emergency laboratory. In the sigma metric calculation TEa (total permissible error) rates, the values determined by RiliBAK (German Guidelines for Quality) were used. The causes of errors of poorly performing tests were evaluated with the quality goal index (QGI). Results : At the results, PCO2 (Level 2) in Instrument I, Lactate (Level 1-2) in Instrument II and pCO2 (Level 1-2) in Instrument III are the tests with sigma values below 4. When we look at the low performance problems, precision in Instrument I pCO2 (Level 2), accuracy in Instrument II lactate (Level 1-2) and accuracy in Instrument III pCO2 (Level 1-2) were detected. Conclusion : This study has allowed us to monitor laboratory blood gas testing performance very closely. With the 6 sigma methodology we have captured underperforming tests and investigated the reasons behind them

Neonatal CSF glucose measured by blood gas analyzer, glucometer, and standard laboratory methods.

To determine agreement between neonatal cerebrospinal fluid (CSF) glucose measured by standard laboratory method versus blood gas analyzers (BGA) and glucometers. This prospective, observational, cross-sectional study was conducted in a level III neonatal unit on 97 neonates undergoing lumbar puncture. Agreement was estimated by Lin's coefficient of concordance and Bland-Altman plot. Lin's coefficient of concordance between the CSF laboratory and BGA glucose values was higher than that between CSF laboratory and glucometer glucose {P value < 0.001}. Bland-Altman plot of CSF glucose values by laboratory and BGA methods showed a bias of -0.137 mmol/l. The plot of laboratory versus glucometer methods showed a bias of -0.863 mmol/l. A linear regression equation to predict laboratory CSF glucose from BGA values and glucometer values had an R2 of 0.975 and 0.971 respectively. CSF glucose measured by blood gas analyzers may be used as a point-of-care test among neonates. Not applicable.

Evaluating the Accuracy of Off-Label Placement of Pulse Oximetry Sensors in Comparison to On-Label Placement in the Adult Cardiac Intensive Care Unit Patient Population.

Continuous pulse oximetry (Spo2) is a commonly utilized tool to obtain an indirect, noninvasive measurement of hemoglobin oxygen saturation. Difficulty obtaining measurement with Spo2 sensors can lead nurses to try off-label sites until they find placement that provides a signal. Currently, there is limited evidence to support this application. The purpose of this study was to evaluate the accuracy of off-label placement of pulse oximetry sensors in comparison to on-label placement in adult cardiac intensive care patients. Data were collected on 24 participants. At the time of a medically necessary arterial blood gas laboratory draws, 4 Spo2 measurements were gathered from an on-label finger sensor, an off-label finger sensor, an on-label ear sensor, and an off-label ear sensor. Results were analyzed using 4 Pearson correlation coefficients, Bland-Altman plots, and 2 linear mixed-effect models. Our study found that while both our on-label finger and off-label finger pulse oximetry sensor overestimated when compared to the arterial hemoglobin saturation (gold standard), there was greater overestimation found with the off-label placement. Though there was not a significant difference observed between the ear probe on the nose and the gold standard, figures examining off-label ear probe and gold standard measures show that, in lower ranges of oxygen saturation, the off-site probe substantially overestimates true oxygen saturation, while in higher ranges of oxygen saturation, the off-site ear probe underestimates true oxygen saturation. No changes should be made to the current practice of using pulse oximetry sensor placement.

Comparison of blood gas parameters with hematological and biochemical parameters in critically III intensive care patients connected to mechanical ventilation

Objective: The primary aim of this study was to compare blood gas parameters with laboratory parameters in critically ill intensive care patients who were connected to mechanical ventilation. Our secondary aim was to evaluate the effects of blood gas and laboratory parameters on mortality. Materials and Method: Critical patients over the age of 18 who were admitted to intensive care unit from emergency room or clinics and monitored with mechanical ventilation between January 1, 2021, and December 30, 2021, were included in this study. Analyses were done with the R 4.3.1 (R Core Team) program. Statistical significance was defined by p &lt; 0.05. Results: A total of 150 patients were included in this study, and 42.6% of them were male. 62% of the men and 50% of the women in this study died. We studied the trend accuracy of laboratory hemoglobin, hematocrit, sodium, potassium, glucose and blood gas hemoglobin, hematocrit, sodium, potassium, and glucose values using a modified Bland–Altman analysis. When the analyses from the first day were examined, mean bias (LOA g/dl) for hemoglobin was 0.001 (−0.15 to 0.14) and mean bias (LOA mEq/l) for potassium was −0.19 (−0.23 to −0.16). When the third day analyses were examined, mean bias (LOA g/dl) for hemoglobin was 0.29 (−0.05 to 0.63) and mean bias (LOA mEq/l) for potassium was −0.25 (−0.29 to −0.21). Conclusion: Hemoglobin and potassium, which are blood gas parameters, can be used instead of laboratory parameters in clinical decision-making in critically ill intensive care patients on mechanical ventilation.

Clinical evaluation of ventilation mode on acute exacerbation of chronic obstructive pulmonary disease with respiratory failure.

At present, understanding of the most effective ventilation methods for treating chronic obstructive pulmonary disease (COPD) patients experiencing acute worsening symptoms and respiratory failure remains relatively limited. This report analyzed the efficiency and side effects of various ventilation techniques used for individuals experiencing an acute COPD exacerbation. To determine whether pressure-controlled ventilation (PCV) can lower peak airway pressures (PAPs) and reduce the incidence of barotrauma compared to volume-controlled ventilation (VCV), without compromising clinical outcomes and oxygenation parameters. We have evaluated 600 patients who were hospitalized due to a severe COPD exacerbation, with 400 receiving mechanical ventilation for the respiratory failure. The participants were divided into two different groups, who were administered either VCV or PCV, along with appropriate management. We thereafter observed patients' attributes, clinical factors, and laboratory, radiographic, and arterial blood gas evaluations at the start and during their stay in the intensive care unit (ICU). We have also employed appropriate statistical methods for the data analysis. Both the VCV and PCV groups experienced significant enhancements in the respiratory rate, tidal volume, and arterial blood gas values during their time in the ICU. However, no significant distinctions were detected between the groups in terms of oxygenation indices (partial pressures of oxygen/raction of inspired oxygen ratio) and partial pressures of carbon dioxide improvements. There was no considerable disparity observed between the VCV and PCV groups in the hospital mortality (32% vs 28%, P = 0.53), the number of days of ICU stay [median interquartile range (IQR): 9 (6-14) d vs 8 (5-13) d, P = 0.41], or the duration of the mechanical ventilation [median (IQR): 6 (4-10) d vs 5 (3-9) d, P = 0.47]. The PCV group displayed lower PAPs compared to the VCV group (P < 0.05) from the beginning of mechanical ventilation until extubation or ICU departure. The occurrence of barotrauma was considerably lower in the PCV group in comparison to the VCV group (6% vs 16%, P = 0.03). Both VCV and PCV were found to be effective in treating patients with acute COPD exacerbation. However, PCV was associated with lower PAPs and a significant decrease in barotrauma, thus indicating that it might be a safer ventilation method for this group of patients. However, further large-scale study is necessary to confirm these findings and to identify the best ventilation approach for patients experiencing an acute COPD exacerbation.

Prediction prolonged mechanical ventilation in trauma patients of the intensive care unit according to initial medical factors: a machine learning approach

The goal of this study was to develop a predictive machine learning model to predict the risk of prolonged mechanical ventilation (PMV) in patients admitted to the intensive care unit (ICU), with a focus on laboratory and Arterial Blood Gas (ABG) data. This retrospective cohort study included ICU patients admitted to Rajaei Hospital in Shiraz between 2016 and March 20, 2022. All adult patients requiring mechanical ventilation and seeking ICU admission had their data analyzed. Six models were created in this study using five machine learning models (PMV more than 3, 5, 7, 10, 14, and 23 days). Patients’ demographic characteristics, Apache II, laboratory information, ABG, and comorbidity were predictors. This study used Logistic regression (LR), artificial neural networks (ANN), support vector machines (SVM), random forest (RF), and C.5 decision tree (C.5 DT) to predict PMV. The study enrolled 1138 eligible patients, excluding brain-dead patients and those without mechanical ventilation or a tracheostomy. The model PMV > 14 days showed the best performance (Accuracy: 83.63–98.54). The essential ABG variables in our two optimal models (artificial neural network and decision tree) in the PMV > 14 models include FiO2, paCO2, and paO2. This study provides evidence that machine learning methods outperform traditional methods and offer a perspective for achieving a consensus definition of PMV. It also introduces ABG and laboratory information as the two most important variables for predicting PMV. Therefore, there is significant value in deploying such models in clinical practice and making them accessible to clinicians to support their decision-making.

Comparison of pulmonary function test, diffusion capacity, blood gas analysis and CT scan in patients with and without persistent respiratory symptoms following COVID-19

BackgroundLong-lasting symptoms following SARS-CoV2-infection have been described in several studies. However, there is only limited knowledge about the ongoing pathophysiology and the association with pathological findings in medical examinations.MethodsIn this post hoc analysis of a prospective trial, 135 patients following COVID-19 were enrolled and grouped with respect to the presence or absence of respiratory ongoing symptoms following COVID-19. Pulmonary function test (PFT), diffusion capacity measurement (TLCO SB and TLCO/VA), blood gas analysis (BGA), laboratory tests and high-resolution computed tomography (HRCT) of patients with persistent respiratory symptoms were compared to those of asymptomatic patients.ResultsIn this analysis, 71% (96/135) of all patients (mean age 49 years; range 20–91 years) reported long-lasting symptoms after a median (IQR) of 85 days (60–116) following COVID-19 whereby 57.8% (78/135) complained about persistent pulmonary symptoms. Pathological findings in blood test, PFT, TLCO, BGA and/or HRCT were found in 71.8% and 64.1% of patients with and without long-lasting respiratory symptoms respectively. Patients with persistent respiratory symptoms were significantly younger and presented a significant lower FVC (%), TLC (L), and TLCO SB compared to asymptomatic patients (p < 0.05). The multiple logistic regression results in a significant effect of age (p = 0.004) and TLCO SB (p = 0.042).ConclusionFollowing COVID-19, a large proportion of patients experience ongoing symptoms, whereby the respiratory symptoms are the predominant complaints. Compared to asymptomatic patients, patients with ongoing symptoms were younger and presented a significant lower FVC, TLC and TLCO SB. The multiple logistic regression demonstrated only a significant association between the TLCO SB as the only PFT parameter and the perceived symptoms.

Alveolar Arterial Gradient and Respiratory Index in Predicting the Outcome of COVID-19 Patients; a Retrospective Cross-Sectional Study

Introduction:Alveolar arterial (A-a) oxygen gradient and respiratory index can be of immense help for the critical care physician in clinical decision making. This study aimed to evaluate the potential application of A-a oxygen gradient and respiratory index in predicting the survival of COVID-19 patients in intensive care unit (ICU).Method:This is a retrospective cross-sectional study involving 215 adult patients with COVID-19 disease, admitted to the ICU between 1st April 2020 and 30 June 2021. Details regarding demographic variables, comorbidities, laboratory and arterial blood gas (ABG) findings were recorded. Alveolar-arterial gradient and respiratory index were calculated and tested as predictors of survival. Result:The mean age of the patients was 51.92 years (65.6 % male). Hypertension was the most common comorbidity and oxygen via non-rebreathing mask was the most common modality used at the time of ICU admission. Mortality was 28.37% and average length of stay was 12.84 days. Patients who died were older (p=0.02), mostly male (p=0.017), had at least one comorbidity (p<0.001), and higher heart rate and respiratory rate (<0.001 and p=0.03, respectively), lower pH on arterial blood gas (ABG) (p=0.002), higher FiO2 requirement (p<0.001), and increased A-a oxygen gradient on admission compared to survivors. According to receiver operating characteristic (ROC) curve analysis, A-a oxygen gradient and respiratory index were not sensitive or specific in predicting mortality in the studied patient subset. Conclusion:A-a oxygen gradient and respiratory index calculated at time of admission to ICU in patients with COVID-19 were poor predictors of survival.

Automated prediction of COVID-19 mortality outcome using clinical and laboratory data based on hierarchical feature selection and random forest classifier

Early prediction of COVID-19 mortality outcome can decrease expiration risk by alerting healthcare personnel to assure efficient resource allocation and treatment planning. This study introduces a machine learning framework for the prediction of COVID-19 mortality using demographics, vital signs, and laboratory blood tests (complete blood count (CBC), coagulation, kidney, liver, blood gas, and general). 41 features from 244 COVID-19 patients were recorded on the first day of admission. In this study, first, the features in each of the eight categories were investigated. Afterward, features that have an area under the receiver operating characteristic curve (AUC) above 0.6 and the p-value criterion from the Wilcoxon rank-sum test below 0.005 were used as selected features for further analysis. Then five feature reduction methods, Forward Feature selection, minimum Redundancy Maximum Relevance, Relieff, Linear Discriminant Analysis, and Neighborhood Component Analysis were utilized to select the best combination of features. Finally, seven classifiers frameworks, random forest (RF), support vector machine, logistic regression (LR), K nearest neighbors, Artifical neural network, bagging, and boosting were used to predict the mortality outcome of COVID-19 patients. The results revealed that the combination of features in CBC and then vital signs had the highest mortality classification parameters, respectively. Furthermore, the RF classifier with hierarchical feature selection algorithms via Forward Feature selection had the highest classification power with an accuracy of 92.08 ± 2.56. Therefore, our proposed method can be confidently used as a valuable assistant prognostic tool to sieve patients with high mortality risks.

Helmet Continuous Positive Airway Pressure in COVID-19 Related Acute Respiratory Distress Syndrome in Respiratory Intermediate Care Unit

Background: The SARS-CoV-2 outbreak spread in Lombardy Region (Italy) rapidly saturating intensive care unit beds, forcing the application of noninvasive respiratory support in RICU. Objectives: We aimed to analyze the effects of helmet CPAP in COVID19- related ARDS in RICU. The primary outcome was CPAP failure, defined as the occurrence of either intubation or death due to any cause during RICU stay; the secondary one was the identification of factors related to patients’ prognosis. Methods: 150 consecutive patients with ARDS due to COVID-19 and referred to Vimercate Hospital (MB) between March and May 2020 were enrolled. All patients were treated with helmet CPAP. Demographics, clinical and laboratory tests and blood gas analysis were collected. Results: Patients had a mean (SD) age of 62 (±11) years. The worst PaO2/ FiO2 ratio during continuous positive airway pressure stratified the subjects in mild (26/150), moderate (39/150) and severe (85/150) ARDS. Most of patients were treated with systemic corticosteroids (79%). 93 patients (62%) were successfully treated while 57 (38%) failed; of the latter, 32 patients were transferred in the intensive care unit to receive invasive mechanical ventilation. Dimer test and ferritin at admission, use of steroids, P/F in oxygen at admission and age were independently associated with CPAP failure. The severity of ARDS and the use of steroids strongly correlate with clinical outcomes. Mortality rate in our cohort of patients was 28%. Conclusions: The application of helmet CPAP in RICU and the administration of corticosteroids in COVID19-related ARDS are associated with satisfactory clinical outcomes.

Comprehensive Review on Epidemiology, Diagnosis and Auspicious Management of COVID 19

:COVID-19 has been identified as a major international concern and global challenge for public health. We have discussed COVID-19 as an infectious disease creating a pandemic situation aross the globe and various tests that have been carried out to detect and treat the infection along with the possibility of finding a vaccination and its results. We have reviewed diagnostic tests such as serological detection, rapid antibody test, nucleic acid test, polymerase chain reaction test, high sophistication molecular-based laboratory testing (USA) and blood gas analyzer aiding. We have reviewed effective drug therapies and their results along with various drugs like Hydroxychloroquine in combination with azithromycin and other drugs like remdesivir, favipiravir, lopinavir and ritonavir tried individually. We have discussed in detail the current research on vaccination conducted by the Oxford University, UK. Our review highlights the success of drug therapy and vaccine trials conducted on sample human populations giving a hope to control the pandemic in the future.

Effects of Pneumatic Tube Transport on Blood Gas and Supplemental Analytes.

Pneumatic tube transport of blood gas samples is a common method of delivery within a facility. The effects of pneumatic tube transport on blood gas analysis has been studied. However, other analytes that are often assessed in blood gas analysis (eg, electrolytes, metabolites, and oximetry) are not typically included in these studies. We sought to investigate the impact of pneumatic tube transport on some of these other analytes. The study was conducted at the blood gas laboratory at the University of Utah Hospital. A split sample comparison was performed. Both samples were walked to a pneumatic tube station, where one sample was sent via tube to the blood gas laboratory, while the other sample was walked back to blood gas laboratory. We examined 2 samples from each of the 27 different pneumatic tube stations in this hospital. Results were graphed with upper and lower control limits set to conform to acceptable College of American Pathologists proficiency testing evaluation criteria. Data were compared using the Student t test. Differences between walked and tubed specimens were neither clinically nor statistically significant. Pneumatic tube transport of blood gas specimens is acceptable for blood gas and supplementary analytes, as evidenced by multiple points of evaluation, including statistical analysis, clinical judgment, and concordance with regulatory guidelines.

Reducing Point-of-care Blood Gas Testing in the Intensive Care Unit through Diagnostic Stewardship: A Value Improvement Project.

Overutilization of point-of-care (POC) testing may reduce the overall value of care due to high-cost cartridges, need for staff training, and quality assurance requirements. The Diagnostic Stewardship group at Cincinnati Children's Hospital Medical Center assembled a multidisciplinary team to reduce the use of POC blood gas testing by 20% in the pediatric intensive care unit (PICU). Key drivers of test overutilization included poor knowledge of cost, concern with testing turnaround time, and a lack of a standard definition of when a POC test was appropriate. We calculated weekly the outcome measure of POC blood gas tests per PICU patient-day and a balancing measure of blood gas result turnaround time using data extracted from the electronic medical record. Interventions focused on staff education, the establishment of a standard practice guideline for the use of POC testing, and improving turnaround time for laboratory blood gas testing. Over the baseline period starting July 2016, a median of 0.94 POC blood gas tests per PICU patient-day was ordered. After initial staff training, the rate was reduced to 0.60 tests per PICU patient-day and further reduced to 0.41 tests per PICU patient-day after a formal policy change was adopted. We have sustained this rate for 15 months through June 2018. Institutional direct cost savings were estimated to be $19,000 per year. Our improvement initiative was associated with a significant and rapid reduction in the use of POC testing in the PICU. Interventions focused on cost awareness, and a formal guideline helped establish a consensus around appropriate utilization.

Comparison of Arterial Blood Gas Analysis versus Central Laboratory Electrolyte and Hemoglobin Determination in Birat Medical College and Teaching Hospital

Introduction: Electrolyte and hemoglobin measurement are the integral part of management of critically ill patient. There can be a wide variation in the electrolyte and hemoglobin measurement in critically ill patient between arterial blood gas analyzer and central laboratory auto analyzer.&#x0D; Objective: To compare the electrolytes (sodium, potassium and chloride) and hemoglobin level measured by arterial blood gas analyzer and laboratory analyzer.&#x0D; Methodology: This was a prospective cross-sectional comparative study comparing the electrolytes (sodium, potassium and chloride) and hemoglobin measurement between arterial blood gas analyzer and laboratory auto analyzer. The study included 124 paired blood samples from the patient admitted in intensive care unit of Birat Medical College Teaching Hospital in two months duration. The arterial sample and venous sample for electrolytes and hemoglobin measurement were taken simultaneously or not more than one hour apart and analysis was done by arterial blood gas analyzer and central laboratory auto analyzer accordingly. The values of electrolytes and hemoglobin measured by two different analyzers were finally compared for variation.&#x0D; Result: The mean difference calculated for sodium potassium and chloride in ABG machine and Auto-analyzers were 0.57 mmol/l.-0.04mmol/l and 1.71mmol/l respectively. These data were within the acceptable range of United States Clinical Laboratory Improvement Amendments(USCLIA). The mean difference derived for hemoglobin in ABG and Auto-analyzers was 0.16g/dl which was not consistent with the range of United States Clinical Laboratory Improvement Amendments (USCLIA)&#x0D; Conclusion: The measurement of electrolyte namely sodium, potassium and chloride in ABG machines and Auto-analyzers of central lab were comparable while hemoglobin was not comparable under the USCLIA guidelines.

POC Assessment of Combined Umbilical Arterial and Venous Lactate: A Potential Screening Test for Neonatal Acidosis [OP04-7D

INTRODUCTION: Umbilical artery (UA) lactate and pH aid the diagnosis of neonatal acidosis. This study examines the relationship between point-of-care (POC) measurement of combined umbilical arterial and venous (CUAV) lactate and UA lactate and pH to determine whether this POC assessment could serve as an alternative screening modality for neonatal acidosis. METHODS: In this prospective cohort study, UA and CUAV cord blood samples were collected from vaginal and cesarean deliveries occurring between June and August 2019 at a tertiary care center. UA samples were analyzed for pH and lactate using a standard laboratory blood gas analyzer (GEM 4000). CUAV lactate was analyzed at the POC (StatStrip Xpress Lactate Meter, off-label indication, IRB-approved) as well as on the blood gas analyzer. Short-term neonatal outcomes, including 1- and 5- minute APGAR scores and NICU admission rates were also assessed. RESULTS: N=190. There was a statistically significant correlation between POC CUAV lactate concentrations and UA lactate concentrations (R2=0.806 P=2.2 x 10-16). Additionally, there was a statistically significant correlation between the CUAV lactate concentrations obtained using the POC device and the GEM analyzer (R2=0.934 P=2.2 x 10-16). R2=0.95 for technical replicates of POC CUAV lactate concentration measurements. There was no statistically significant association between POC CUAV lactate and UA pH (R2=0.223 P=2.4 x 10-6). CONCLUSION: POC testing of CUAV lactate is reliable and closely correlated with UA lactate concentrations, making POCT CUAV lactate a feasible screening test for neonatal acidosis. More data is needed to establish the sensitivity and specificity of this test and its association with clinical neonatal outcomes.

Evaluation of Usefulness of Mannheim Peritonitis Index and APACHE II Score in Predicting Mortality and Morbidity in Patients with Peritonitis- A Prospective Diagnostic Test Study

Introduction: Peritonitis, defined as inflammation of the peritoneal cavity can be of various causes, and is one of the most common surgical emergencies. This continues to be a challenge to diagnose and treat. Early intervention is essential to select patients who will need intensive care which brings out better outcome for the patients. This also helps us use the resources optimally. Over years, many scoring systems have been developed and studied to predict outcomes in patients with peritonitis. Aim: To evaluate the ability of Mannheim Peritonitis Index (MPI) and APACHE II (Acute Physiology And Chronic Health Evaluation II) scores in predicting mortality and morbidity in patients with peritonitis. Materials and Methods: A prospective, observational study was conducted at Christian Medical College and Hospital, Vellore, Tamil Nadu, India, for a period of two years from September 2014 to August 2016. A total of 78 patients were recruited for this study. These patients were scored with MPI and APACHE II scores. The primary outcome studied was in hospital death or discharge. The secondary outcome studied was morbidity in terms of local and systemic complications. The risk factors associated with mortality in patients with peritonitis were also studied. The best cut-off value for MPI and APACHE II from the data was calculated using Yuden index. The sensitivity, specificity and likelihood ratios were calculated and presented with 95% Confidence Interval(CI). The sub-group analysis was done for risk factors and complications. Results: There were more males than females. Age ≥48 years (p=0.002) and serum creatinine ≥1.3 g/dL (p=0.012) were found to be significant risk factors for mortality. The sensitivity and specificity of MPI ≥27 in predicting mortality was found to be 90% and 57% respectively. The sensitivity and specificity of APACHE II score ≥10 in predicting mortality was found to be 40% and 78%, respectively. MPI scores ≥27 were strongly associated with morbidity like prolonged ICU stay (p=0.004), mechanical ventilation requirement (p=0.001) and need for dialysis (p=0.035). Conclusion: Present study showed MPI to be a better predictor of mortality than APACHE II, though APACHE II showed better specificity. MPI score also was helpful in predicting morbidity such as prolonged ICU stay, mechanical ventilation requirement postoperatively and need for dialysis postoperatively. MPI was easier to use as it contained lesser variables. MPI could be of use in rural areas with no facility for laboratory investigations and blood gas analysis.

Intra-patient potassium variability after hypothermic cardiac arrest: a multicentre, prospective study

BackgroundTo date, the decision to set up therapeutic extra-corporeal life support (ECLS) in hypothermia-related cardiac arrest is based on the potassium value only. However, no information is available about how the analysis should be performed. Our goal was to compare intra-individual variation in serum potassium values depending on the sampling site and analytical technique in hypothermia-related cardiac arrests.MethodsAdult patients with suspected hypothermia-related refractory cardiac arrest, admitted to three hospitals with ECLS facilities were included. Blood samples were obtained from the femoral vein, a peripheral vein and the femoral artery. Serum potassium was analysed using blood gas (BGA) and clinical laboratory analysis (CL).ResultsOf the 15 consecutive patients included, 12 met the principal criteria, and 5 (33%) survived. The difference in average potassium values between sites or analytical method used was ≤1 mmol/L. The agreement between potassium values according to the three different sampling sites was poor. The ranges of the differences in potassium using BGA measurement were − 1.6 to + 1.7 mmol/L; − 1.18 to + 2.7 mmol/L and − 0.87 to + 2 mmol/L when comparing respectively central venous and peripheral venous, central venous and arterial, and peripheral venous and arterial potassium.ConclusionsWe found important and clinically relevant variability in potassium values between sampling sites. Clinical decisions should not rely on one biological indicator. However, according to our results, the site of lowest potassium, and therefore the preferred site for a single potassium sampling is central venous blood. The use of multivariable prediction tools may help to mitigate the risks inherent in the limits of potassium measurement.Trial registrationClinicalTrials.gov Identifier: NCT03096561.

Assessment of Accuracy of Continuous Noninvasive versus Invasive Method of Hemoglobin Estimation in Patients Undergoing Pituitary Surgery

Abstract Aim Determination of hemoglobin (Hb) concentration by standard methods is time consuming, invasive, and intermittent. Noninvasive (NI) methods of Hb estimation are less time consuming, and reduce the risk of infection, number of required working personnel, and long-term costs. In this study, we aimed to find the accuracy of Hb values at various time points using noninvasive (NI) Hb monitoring and standard invasive techniques such as laboratory (LabHb) and arterial blood gas (ABG). Methods All American Society of Anesthesiologists (ASA) physical grade I and II adult patients between 18 and 65 years of either gender undergoing pituitary surgery under general anesthesia were included over a period of 1 year. Samples were collected for Hb estimation from the arterial line (aHb) using ABG analyzer machine and LabHb using automated Hb analyzer. Simultaneously, Hb reading from the NI Hb monitor was recorded using Masimo Spot Hemoglobin Check Device. Bland–Altman plot was used to find out agreement between Hb values drawn from three different techniques. A p-value &lt; 0.05 was considered significant. Results A total of 30 patients participated in the study. The male to female ratio was 13:17. Statistical analysis showed poor correlation between the invasive and NI methods of Hb estimation. Conclusion NI method of Hb estimation may be successfully used in clinical practice, replacing estimation from ABG analysis or laboratory tests. However, NI method cannot replace the invasive methods of Hb estimation.

Relocation of blood gas laboratory to the emergency department helps decrease lactic acid values

ImportanceEmergency Physicians often rely on Lactic Acid (LA) values to make important clinical decisions. Accuracy of LA values improve when blood gas analysis is performed in the emergency department (ED) as opposed to a satellite laboratory (SL). ObjectiveTo investigate an association between blood gas laboratory location and accuracy of ED lactic acid samples. MethodsThe study team evaluated lactic acid values from venous and arterial blood gas samples drawn between June 1, 2015 and September 30, 2016. The study was exempt from institutional review board approval. Samples were separated into two groups: those which were drawn prior to and after relocation of the blood gas laboratory to the ED. The data, including patient demographic characteristics, acute illness severity indices, and blood gas results were compared within and between each group using t-test for continuous variables and chi-square test for categorical variables. The primary outcome was the mean lactate value measured in the SL group in 2015 compared to the ED group in 2016. Potassium and creatinine values were measured between the two groups as secondary outcomes. ResultsOf the 21,595 consecutive samples drawn, 10,363 samples were from the SL group and 11,232 from the ED group. The SL group included 5458 (52.7%) women; mean (SD) age was 61.8 (21.0). The ED group contained 5860 (52.2%) women; mean (SD) age was 61.7 (20.5). Mean Emergency Severity Index (ESI) were the same in each group at 2.31 and rates of Systemic Inflammatory Response Syndrome (SIRS) were also equivalent in each group at 22.2%. Significant differences were found between LA values in the SL group (mean 2.21mmol/L) and in the ED group (mean 1.99mmol/L) with a p value of <0.0001. There was a small statistical significance between the difference in potassium values in the SL group (mean 3.98meq/L) compared to the ED Group (mean 3.96meq/L) with a p value of 0.022. No significant difference was found between the creatinine values. Conclusions and RelevanceThese results suggest that mean lactate values decreased when measured in an ED blood gas laboratory and may provide more accurate LA results than blood gas samples analyzed at an SL blood gas laboratory within the same institution. Hospitals may consider moving blood gas laboratories to the ED to improve accuracy of one of the most important early blood markers used in the definition of sepsis and in the identification of the critically ill.

WITHDRAWN: Relocation of blood gas laboratory to the emergency department helps decrease lactic acid values

The Publisher regrets that this article is an accidental duplication of an article that has already been published, http://dx.doi.org/10.1016/j.ajem.2018.03.017. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.