Implementation of an arterial blood gas indication algorithm in cardiac surgery.

PROBLEM: Arterial blood gasses (ABGs) account for an estimated 10-20% of all costs during an ICU stay. Non-clinically indicated ABGs increased costs of care, lengths of stay, ventilator days, and line days, increasing the risk of adverse outcomes in already vulnerable critically ill patients. A cardiac surgery intensive care unit (CSICU) within a large urban mid-Atlantic academic medical center accounted for 31% of the entire institution's ABG analyses between 2018-2019, was identified as a top utilizer due to inappropriate ordering practices compared to current guidelines. PURPOSE: The purpose of this quality improvement project was to implement an algorithm using evidence-based guidelines that identified appropriate standardized clinical indications for ABGs, with the intention of reducing non-clinically indicated blood gas analyses orders within the CSICU. Anticipated outcomes of this practice change included decreasing the total volume of ABGs sent, resulting in reduced costs of care, lengths of stay, and improved morbidity and mortality rates. METHODS: An evidence-based ABG indication algorithm was created focusing on acute changes in oxygenation, ventilation, acid base balance; changes in hemodynamics, post-operative baseline, and for patient ABGs to correlate with extra-corporeal membranous oxygenation values. Routine ABGs for monitoring were eliminated. Implementation occurred over fourteen-weeks in the fall of 2020 following staff and provider education. Training emphasized the use of non-invasive monitoring such as pulse-oximetry and capnography. Compliance and gross laboratory totals and indications were obtained from weekly auditing. RESULTS: There was an 8.8% reduction in ABGs obtained and 32% decrease in ABGs per patient day. The most common indications were extra-corporeal membranous oxygenation (ECMO)-correlated ABGs, post-operative, and changes in oxygenation and/or ventilation; 7.8% were non-indicated. CONCLUSIONS: Implementation of an ABG indication algorithm resulted in fewer ABGs sent, mostly due to a reduction in routine monitoring, and ABGs were more likely to be clinically indicated in response to an acute concern. Implementing an ABG indication algorithm is safe, feasible, and can lead to significant cost reductions for the institution.

Comparative analysis of hemoglobin, potassium, sodium, and glucose in arterial blood gas and venous blood of patients with COPD.

The study aims to assess the accuracy of the arterial blood gas (ABG) analysis in measuring hemoglobin, potassium, sodium, and glucose concentrations in comparison to standard venous blood analysis among patients diagnosed with chronic obstructive pulmonary disease (COPD). From January to March 2023, results of ABG analysis and simultaneous venous blood sampling among patients with COPD were retrospectively compared, without any intervention being applied between the two methods. The differences in hemoglobin, potassium, sodium, and glucose concentrations were assessed using a statistical software program (R software). There were significant differences in the mean concentrations of hemoglobin (p < 0.001), potassium (p < 0.001), and sodium (p = 0.001) between the results from ABG and standard venous blood analysis. However, the magnitude of the difference was within the total error allowance (TEa) of the United States of Clinical Laboratory Improvement Amendments (US-CLIA). As for the innovatively studied glucose concentrations, a statistically significant difference between the results obtained from ABG (7.8 ± 3.00) mmol·L-1 and venous blood (6.72 ± 2.44) mmol·L-1 was noted (p < 0.001), with the difference exceeding the TEa of US-CLIA. A linear relationship between venous blood glucose and ABG was obtained: venous blood glucose (mmol·L-1) = - 0.487 + 0.923 × ABG glucose (mmol·L-1), with R2 of 0.882. The hemoglobin, potassium, and sodium concentrations in ABG were reliable for guiding treatment in managing COPD emergencies. However, the ABG analysis of glucose was significantly higher as compared to venous blood glucose, and there was a positive correlation between the two methods. Thus, a linear regression equation in this study combined with ABG analysis could be helpful in quickly estimating venous blood glucose during COPD emergency treatment before the standard venous blood glucose was available from the medical laboratory.

Goal-directed fluid therapy guided by plethysmographic variability index versus conventional liberal fluid therapy in neonates undergoing abdominal surgery: A prospective randomized controlled trial.

BACKGROUND: Intraoperative fluid therapy maintains normovolemia, normal tissue perfusion, normal metabolic function, normal electrolytes, and acid-base status. Plethysmographic variability index has been shown to predict fluid responsiveness but its role in guiding intraoperative fluid therapy is still elusive. AIMS: The aim of the present study was to compare intraoperative goal-directed fluid therapy based on plethysmographic variability index with liberal fluid therapy in term neonates undergoing abdominal surgeries. METHODS: A prospective randomized controlled study was conducted in a tertiary care centre, over a period of 18 months. A total of 30 neonates completed the study out of 132 neonates screened. Neonates with tracheoesophageal fistula, congenital diaphragmatic hernia, congenital heart disease, respiratory disorders, creatinine clearance <90 mL/min and who were hemodynamically unstable were excluded. Neonates were randomized to goal-directed fluid therapy group where the plethysmographic variability index was targeted at <18 or liberal fluid therapy group. Primary outcome was comparison of total amount of fluid infused intraoperatively in both the groups. Secondary outcomes included intraoperative and postoperative arterial blood gas parameters, biochemical parameters, use of vasopressors, number of fluid boluses, complications and duration of hospital stay. RESULTS: There was no significant difference in total intraoperative fluid infused [90 (84-117.5 mL) in goal-directed fluid therapy and 105 (85.5-144.5 mL) in liberal fluid therapy group (p = .406)], median difference (95% CI) -15 (-49.1 to 19.1). There was a decrease in serum lactate levels in both groups from preoperative to postoperative 24 h. The amount of fluid infused before dopamine administration was significantly higher in liberal fluid therapy group (58 [50.25-65 mL]) compared to goal-directed fluid therapy group (36 [22-44 mL], p = .008), median difference (95% CI) -22 (-46 to 2). In postoperative period, the total amount of fluid intake over 24 h was comparable in two groups (222 [204-253 mL] in goal-directed fluid therapy group and 224 [179.5-289.5 mL] in liberal fluid therapy group, p = .917) median difference (95% CI) cutoff -2 (-65.3 to 61.2). CONCLUSION: Intraoperative plethysmographic variability index-guided goal-directed fluid therapy was comparable to liberal fluid therapy in terms of total volume of fluid infused in neonates during perioperative period. More randomized controlled trials with higher sample size are required. TRIAL REGISTRATION: Central Trial Registry of India (CTRI/2020/02/023561).

Oxygenation during general anesthesia in pediatric patients: A retrospective observational study.

STUDY OBJECTIVE: Protocols are used in intensive care and emergency settings to limit the use of oxygen. However, in pediatric anesthesiology, such protocols do not exist. This study aimed to investigate the administration of oxygen during pediatric general anesthesia and related these values to PaO2, SpO2 and SaO2. DESIGN: Retrospective observational study. SETTING: Tertiary pediatric academic hospital, from June 2017 to August 2020. PATIENTS: Patients aged 0-18 years who underwent general anesthesia for a diagnostic or surgical procedure with tracheal intubation and an arterial catheter for regular blood withdrawal were included. Patients on cardiopulmonary bypass or those with missing data were excluded. Electronic charts were reviewed for patient characteristics, type of surgery, arterial blood gas analyses, and oxygenation management. INTERVENTIONS: No interventions were done. MEASUREMENTS: Primary outcome defined as FiO2, PaO2 and SpO2 values were interpreted using descriptive analyses, and the correlation between PaO2 and FiO2 was determined using the weighted Spearman correlation coefficient. MAIN RESULTS: Data of 493 cases were obtained. Of these, 267 were excluded for various reasons. Finally, 226 cases with a total of 645 samples were analyzed. The median FiO2 was 36% (IQR 31 to 43), with a range from 20% to 97%, and the median PaO2 was 23.6 kPa (IQR 18.6 to 28.1); 177 mmHg (IQR 140 to 211). The median SpO2 level was 99% (IQR 98 to 100%). The study showed a moderately positive association between PaO2 and FiO2 (r = 0.52, p < 0.001). 574 of 645 samples (89%) contained a PaO2 higher than 13.3 kPa; 100 mmHg. CONCLUSIONS: Oxygen administration during general pediatric anesthesia is barely regulated. Hyperoxemia is observed intraoperatively in approximately 90% of cases. Future research should focus on outcomes related to hyperoxemia.

Analysing arterial blood gas results using the RoMe technique.

Arterial blood gas (ABG) analysis is a fundamental skill in healthcare practice, particularly when caring for acutely unwell or deteriorating patients. It can be useful in the assessment of patients' acid-base balance and gas exchange, thereby informing appropriate care and management. However, many nurses find interpreting ABG results challenging. This article outlines a simplified approach to ABG analysis using three main values - pH, partial pressure of carbon dioxide and bicarbonate - and applying the RoMe ('Respiratory opposite, Metabolic equal') technique. It also provides brief descriptions of selected acid-base imbalances and explains how to identify whether these are uncompensated, partially compensated or fully compensated.

Effect of syringe underfilling on the quality of venous blood gas analysis.

OBJECTIVES: There is limited information on the influence of collecting small amounts of blood on the quality of blood gas analysis. Therefore, the purpose of this study was to investigate the effects of different degrees of underfilling of syringes on test results of venous blood gas analysis. METHODS: Venous blood was collected by venipuncture from 19 healthcare workers in three 1.0 mL syringes for blood gas analysis, by manually aspirating different volumes of blood (i.e., 1.0, 0.5 and 0.25 mL). Routine blood gas analysis was then immediately performed with GEM Premier 5,000. The results of the two underfilled syringes were compared with those of the reference syringe filled with appropriate blood volume. RESULTS: The values of most assayed parameters did not differ significantly in the two underfilled syringes. Statistically significant variations were found for lactate, hematocrit and total hemoglobin, the values of which gradually increased as the fill volume diminished, as well as for sodium concentration, which decreased in both insufficiently filled blood gas syringes. The bias was clinically meaningful for lactate in syringe filled with 0.25 mL of blood, and for hematocrit, total hemoglobin and sodium in both syringes containing 0.5 and 0.25 mL of blood. CONCLUSIONS: Collection of smaller volumes of venous blood than the specified filling volume in blood gas syringes may have an effect on the quality of some test results, namely lactate, hematocrit, total hemoglobin and sodium. Specific indications must be given for standardizing the volume of blood to be collected within these syringes.

Low partial pressure of oxygen causes significant and unrecognized under-recovery of glucose on blood gas analyzers.

BACKGROUND: Blood gas analyzers employing glucose-oxidase biosensors under-recover glucose when pO2 is low. The manufacturer of the GEM®Premier™ series of analyzers introduced an algorithm to detect specimens at risk of low pO2 interference. We investigated the reliability of this algorithm. METHODS: Whole blood specimens were tested by GEM®Premier™ 4000 (GEM 4000) and 5000 (GEM 5000). Specimens with an incalculable ("incalc") error code for glucose result or that had a glucose ≥ 20 mmol/L were retested on a second analyzer of the same type within 5 min over the course of 30 months in 5 hospitals in Calgary, Alberta. Discordant retests were defined as either: 1) paired numeric results with a difference >10 %, or 2) an "incalc" code that yielded a numeric result upon retesting. Glucose recovery in relation to pO2 level was assessed by comparing specimens experimentally depleted of pO2 between GEM 5000 and a laboratory analyzer (Siemens Vista®). RESULTS: Of 1,776 glucose tests repeated on the GEM 5000 or 1,544 on GEM 4000, 10% were discordant. GEM 5000 produced twice as many discordant numeric retests versus the GEM 4000 [5.9% (98/1,651) vs 2.7% (38/1,391)]. The majority of "incalc" error codes repeated with a numeric glucose result on both GEM analyzers [(79.7% (122/153) vs 75.2% (94/125)]. Among specimens experimentally depleted of pO2, the GEM 5000 under-recovered glucose by up to 30% compared to the Siemens Vista and were not flagged by an "incalc" code. CONCLUSIONS: The algorithm in the GEM®PremierTM series of analyzers that flags specimens at risk for glucose under-recovery due to low pO2 does not reliably detect specimens at risk for glucose under-recovery.

A comparison of continuous blood gas monitors during cardiopulmonary bypass LivaNova B-Capta, Terumo CDI 500, spectrum medical M4.

INTRODUCTION: Accurate and precise management of blood gas parameters during cardiopulmonary bypass (CPB) is crucial to patient care and outcome. This study compares the data provided by Livanova B-Capta, Terumo CDI500, and Spectrum Medical M4 with the results from a gold standard blood gas analyzer to test accuracy. METHODS: All three continuous blood gas monitoring (CBGM) devices were used simultaneously during CPB on one dedicated HLM. Arterial and venous blood samples of 40 adult patients who underwent elective cardiac surgery with CPB were taken from the CPB circuit. RESULTS: Pre- and post-alignment deviation in percentages are compared with CLIA guidelines. B-Capta data reveals that the deviation pre-alignment is small and within the CLIA threshold for all parameters. Pre-alignment data for CDI 500 is within CLIA threshold for SvO2 and PaO2. The pre-alignment data for the M4 exceeds the CLIA thresholds for all parameters. Post-alignment data for B-Capta and CDI 500 reveals an accurate agreement for Hb and Hct and strong agreement for PaO2. All values for B-Capta and CDI 500 are within CLIA threshold values except for SvO2. Post-alignment the M4 exceeded the CLIA threshold value only for PaO2. CONCLUSION: B-Capta is the only CBGM device that operates within the CLIA guidelines and is in agreement with laboratory values prior to alignment.

Compatibility levels between blood gas analysis and central laboratory hemoglobin and electrolyte tests in pediatric patients: A single-center experience.

INTRODUCTION: We aimed to evaluate the interchangeability of sodium, potassium, hemoglobin, and hematocrit measurement between the blood gas analyzers and laboratory automatic analyzers results. METHODS: This was a retrospective cross-sectional study. The results of 1927 paired samples analyzed simultaneously with the blood gas analyzer and the laboratory automatic analyzer were compared. The Bland-Altman and Cohen's kappa statistic detected the agreement between the two analyses. RESULTS: The limits of agreement (±1.96 standard deviation of the mean difference) were -11.1 to 20.3 for sodium, -1.9 to 0.5 for potassium, -16.1 to 12.9 for hematocrit, and -5.0 to 4.0 for hemoglobin. Agreement between the two analyses was not acceptable within the defined clinically acceptable limits. In addition, none of the kappa values were higher than 0.60, which highlights the lack of agreement between the two analyzers. CONCLUSION: The blood gas analyzers and laboratory automatic analyzers results cannot be used interchangeably.

Defining blood gas analysis stability limits across five sample types.

Accurate reporting of blood gas samples is dependent upon following proper preanalytical sample handling requirements though there is variation for sample acceptability criteria across institutions. We examined five common sample types (arterial, venous, umbilical arterial, umbilical venous and capillary) stored at either room temperature or on crushed ice in a time series (0, 15, 30, 45, 60, 90, 180, 240 min) and applied local regulatory and/or institutional allowable performance limits to determine the need for cold preservation and/or maximum stability time for pH, pO2, pCO2, glucose, lactate, sodium, potassium, chloride, and ionized calcium where applicable in each sample type. Although changes in sample pO2 and/or lactate values were responsible, in part or in whole, for surpassing the allowable limits in nearly all sample types analyzed, this was not uniformly observed across sample types within the typical time limits that are referenced in literature. Furthermore, we demonstrated that cold preservation may not ubiquitously provide longer stability for blood gas specimens and this is dependent on the sample type and analyte in question. Nevertheless, these results demonstrate the known instability of pO2 and lactate and suggest that it may be possible to simplify the monitoring of preanalytical conditions by first evaluating pO2 and lactate in patient blood gas samples if applicable.

Milk-Alkali Syndrome: A Century-old Cause of Hypercalcemia Requires the Addition of Venous Blood Gas in Hypercalcemia Workup.

The Milk-Alkali syndrome (MAS) is identified by the triad of high serum levels of calcium, metabolic alkalosis, and acute kidney injury, usually caused by consuming excessive amounts of calcium and absorbable alkali. If not treated promptly, the syndrome can result in rapid hypercalcemia, acute renal failure, and metastatic calcification. Notably, an increasing number of cases of MAS have been observed, potentially due to the rampant use of calcium-based over-the-counter supplements for the prevention and treatment of osteoporosis in postmenopausal women. Herein, we report a case of severe hypercalcemia due to prolonged intake of calcium carbonate supplements in the absence of any alkali. The case report highlights the importance of including venous blood gas (VBG) analysis as a part of the workup for hypercalcemia, as metabolic alkalosis can help clinch the diagnosis of MAS in the setting of severe hypercalcemia. How to cite this article: Sahu U, Trivedi T, Gupta R. Milk-Alkali Syndrome: A Century-old Cause of Hypercalcemia Requires the Addition of Venous Blood Gas in Hypercalcemia Workup. J Assoc Physicians India 2023;71(9):104-105.

Monitorización hemodinámica integrada: clínica, gasométrica y ecocardiográfica / Integrated hemodynamic monitoring: clinical, gasometric and echocardiographic / Monitorização hemodinâmica integrada: clínica, gasométrica e ecocardiográfica

Introducción: la monitorización hemodinámica constituye un conjunto de técnicas y parámetros que permiten valo rar si la función cardiovascular es la adecuada para mantener la perfusión y la oxigenación tisular que permita sa tisfacer las demandas metabólicas del organismo, valorar el estado y el comportamiento del sistema cardiovascular, orientando sobre la mejor estrategia terapéutica. La presente revisión busca proporcionar una descripción general e integrada de las diferentes técnicas de monitorización, así como aspectos fisiológicos relevantes para su entendi miento y empleo terapéutico. La monitorización hemodinámica acompañada de un adecuado conocimiento de la fisiología cardiovascular permite determinar el estado del sistema cardiovascular, la condición hemodinámica del paciente y la estrategia terapéutica requerida. Su interpretación debe partir de la integración y la correlación de diversos parámetros hemodinámicos.

Introduction: hemodynamic monitoring is a set of techniques and parameters that allow evaluating whether cardio vascular function is adequate to maintain tissue perfusion and oxygenation to satisfy metabolic demands of the or ganism, assess the condition and behavior of the cardiovascular system, providing guidance on the best therapeutic strategy. This review seeks to provide a general and integrated description of the different monitoring techniques, as well as physiological aspects relevant to their understanding and therapeutic use. Hemodynamic monitoring accompanied by an adequate knowledge of cardiovascular physiology allows to determine the state of the cardiovascular system, hemodynamic condition of the patient and therapeutic strategy required, its interpretation must start from the integration and correlation of different hemodynamic parameters.

Introdução: a monitorização hemodinâmica constitui um conjunto de técnicas e parâmetros que permitem avaliar se a função cardiovascular é adequada para manter a perfusão e oxigenação tecidual que permite satisfazer as exi gências metabólicas do organismo, avaliar o estado e comportamento do sistema cardiovascular, orientando sobre a melhor estratégia terapêutica. Esta revisão procura fornecer uma descrição geral e integrada das diferentes técnicas de monitorização, bem como aspectos fisiológicos relevantes para a sua compreensão e utilização terapêutica. A monitorização hemodinâmica acompanhada de um conhecimento adequado da fisiologia cardiovascular permite determinar o estado do sistema cardiovascular, a condição hemodinâmica do doente e a estratégia terapêutica neces sária, a sua interpretação deve partir da integração e correlação de vários parâmetros hemodinâmicos.

Accuracy and stability evaluation of different blood sampling methods in blood gas analysis in emergency patients: A retrospective study.

BACKGROUND: To evaluate the accuracy and stability of arterial blood gas (ABG) results by comparison with venous measurements from routine blood tests, and to compare the accuracy and performance of two sampling syringes, pre-heparinized syringe (PHS) and disposable arterial blood syringe (DABS), in ABG analysis. METHODS: We retrospectively analyzed the practical use of PHS and DABS in collecting ABG samples, involving 500 and 400 patients, respectively. For each patient, in addition to the ABG sample, a venous blood sample was also collected using a venous blood collection tube (VBCT) and used for routine blood tests. Accordingly, patients were referred to as the PHS + VBCT group and DABS + VBCT group. The correlation between arterial and venous values of each blood parameter in each group was evaluated using the interclass correlation coefficient (ICC). Bland-Altman was performed to evaluate the agreement between arterial and venous values and compare the performance of PHS and DABS in ABG sample collection. RESULTS: In the PHS + VBCT group, arterial K+ , Na+ , hemoglobin (Hb), and hematocrit (HCT) were 0.32 mmol/L, 2.90 mmol/L, 2.21 g/L, and 1.27% significantly lower their corresponding venous values while arterial Cl- was 7.60 mmol/L significantly higher than venous Cl- . In the DABS + VBCT group, arterial K+ and Na+ were 0.20 mmol/L and 1.19 mmol/L significantly lower while Cl- and HCT in arterial blood were 5.34 mmol/L and 0.66% significantly higher than their corresponding venous values. In both groups, arterial K+ , Na+ , Hb, and HCT values were highly consistent with their corresponding venous values, with all ICCs greater than 0.70, especially Hb and HCT. Bland-Altman analysis demonstrated that arterial K+ and Na+ were more consistent with venous counterparts in the DABS + VBCT group, with a narrower 95% limits of agreement than the PHS + VBCT group (K+ , -0.7-0.3 mmol/L vs. -1.1 to 0.5 mmol/L; Na+ , -5.8 to 3.4 mmol/L vs. -8.2 to 2.4 mmol/L). CONCLUSION: Arterial blood gas analysis of K+ , Na+ , Hb, and HCT using PHS or DABS for blood sampling is accurate and stable, especially DABS, which can provide clinicians with fast and reliable blood gas results.

AARC Clinical Practice Guidelines: Capillary Blood Gas Sampling for Neonatal and Pediatric Patients.

In the absence of an indwelling arterial catheter, capillary blood gas sampling may be used to evaluate the acid/base and ventilation status of neonatal and pediatric patients with cardiorespiratory conditions. These guidelines were developed from a comprehensive review of the literature to provide guidance for the collection, handling, and interpretation of blood obtained from an arterialized capillary sample. Capillary and venous blood gas measurements are a useful alternative to arterial blood gas measurements for neonatal and pediatric patients who do not require close monitoring of [Formula: see text] In the presence of alterations in body temperature, blood pressure, or peripheral perfusion, agreement between a capillary blood gas with an arterial sample is recommended to determine whether changes in these physiologic conditions reduce reliability. Perfusion to the sample site should be assessed and preference given to blood sampling from a well perfused site, and blood should be analyzed within 15 min of sampling to minimize the propensity for pre-analytical errors. Clinicians should consider re-collecting a blood sample, obtained from an artery, vein, or capillary, when the blood gas or analyte result interpretation does not align with the patient's clinical presentation. A pneumatic tube system can be reliably used to transport blood gas samples collected in a syringe and capillary tube to a clinical laboratory for analysis. To reduce the cumulative pain effect and risk of complications, the capillary puncture procedure should be minimized when possible. Non-pharmacologic interventions should be used to reduce pain associated with capillary blood gas sampling. Automatic lancets are preferred to puncture the skin for capillary blood gas collection.

Comparison of the bovine blood gas parameters produced with three types of portable blood gas analyzers.

BACKGROUND: A definite diagnosis should be made in the bovine practice field, however, it was difficult to perform laboratory analysis immediately. Currently, three types of portable blood gas analyzers are available in Korea. OBJECTIVES: This study aimed to evaluate the correlations among these three analyzers. METHODS: Seventy-two plasma samples from Holstein-Friesian cows were used for blood gas analysis, and three instruments (EDAN i15 Vet, VETSCAN i-STAT, and EPOC) were operated simultaneously. Moreover, plasma calcium levels were compared between these portable analyzers and blood chemistry device, which is usually used in a laboratory environment. Pearson analysis was performed to confirm the correlation of each parameter produced with the three instruments and blood chemistry analyzer. RESULTS: As results, high correlation was observed in parameters of pH, pO2, potassium ion, ionized calcium, and glucose (p < 0.001, r > 0.7). In addition, pCO2 showed a moderate correlation among the three analyzers (p < 0.001, r > 0.5), and there was no correlation among all instruments for sodium ions. There was also a high correlation between ionized calcium from the three portable devices and total calcium from the biochemistry analyzer (p < 0.001, r > 0.9). CONCLUSIONS: In conclusion, there was a high correlation between results from the three different blood gas analyzers used in the bovine clinical field in Korea. Thus, a consistent diagnosis can be made even with different equipment if the operator is aware of the strengths and weaknesses of each piece of equipment and operates it properly.

Detection of preanalytical errors in arterial blood gas analysis.

Introduction: Blood gas analysis (BGA) is an essential test used for years to provide vital information in critically ill patients. However, the instability of the blood gases is a problem. We aimed to evaluate time and temperature effects on blood gas stability. Materials and methods: Arterial blood was collected from 20 patients into syringes. Following BGA for baseline, syringes were divided into groups to stand at 4°C and 22°C for 30, 60, 90, 120 minutes. All were tested for pH, partial pressure of carbon dioxide (pCO2), partial pressure of oxygen (pO2), oxygen saturation (sO2), oxyhemoglobin (O2Hb), sodium, potassium, glucose, lactate, oxygen tension at 50% hemoglobin saturation (p50), and bicarbonate. A subgroup analysis was performed to detect the effect of air on results during storage. Percentage deviations were calculated and compared against the preset quality specifications for allowable total error. Results: At 4°C, pO2 was the least stable parameter. At 22°C, pO2 remained stable for 120 min, pH and glucose for 90 min, lactate and pCO2 for 60 min. Glucose and lactate were stable when chilled. Air bubbles interfered pO2 regardless of temperatures, whereas pCO2 increased significantly at 22°C after 30 min, and pH decreased after 90 min. Bicarbonate, sO2, O2Hb, sodium, and potassium were the unaffected parameters. Conclusions: Correct BGA results are essential, and arterial sample is precious. Therefore, if immediate analysis cannot be performed, up to one hour, syringes stored at room temperature will give reliable results when care is taken to minimize air within the blood gas specimen.

Systematic review and meta-analysis: value of venous blood gas in the diagnosis of acute exacerbation of chronic obstructive pulmonary disease in Emergency Department.

BACKGROUND: at present, arterial blood gas (ABG) analysis is widely used in the diagnosis and treatment evaluation of acute exacerbation of chronic obstructive pulmonary disease (COPD) in emergency department, but it has the risk of thrombosis and bleeding. In recent years, venous blood gas (VBG) analysis has become more and more popular, but its clinical diagnostic value in emergency patients with acute exacerbation of COPD remains unclear. METHODS: relevant clinical studies on the diagnosis of acute exacerbation of COPD by blood gas analysis were searched in Medline, Excerpta Medica Database (EMBASE), Elton B. Stephens. Company (EBSCO), OVID, China Biomedical Database, and Wanfang Database from the establishment of the database to January 2010 to September 2021, Meta-analysis was performed on the data with RevMan5.3. The differences of blood gas analysis indicators potential of hydrogen (pH), partial pressure of carbon dioxide (PaCO2), and hydro-carbonate (HCO3) were compared between the arterial blood gas group and the venous blood gas group. Heterogeneity of results was assessed with Chi2 test and I2 in RevMan5.3. RESULTS: a total of 7 articles with 1,257 subjects were included in this study. Newcastle-Ottawa scale (NOS) scores were higher than six points. In relation to the ABG analysis and VBG analysis, there was no significant difference in the potential of hydrogen (pH) [mean difference (MD) =-0.00, 95% confidence interval (CI) =0.05-0.04, Z=0.19, P=0.85]; however, there were significant differences in the partial pressure of carbon dioxide (PaCO2) (MD =5.32, 95% CI =3.32-7.33, Z=5.20, P<0.00001) and hydro-carbonate (HCO3) (MD =1.05, 95% CI =0.27-1.83, Z=2.63, P=0.009). CONCLUSIONS: there were differences between ABG and VBG in the diagnosis of patients with acute exacerbation of COPD in the emergency department. Due to the small number of included literatures, further verification is needed.

Mathematical Arterialization of Capillary Blood for Blood Gas Analysis in Critically Ill Patients.

BACKGROUND: In clinical practice, capillary blood taken from hyperemized earlobes (CBGE) or fingertips (CBGF) is frequently used as substitute for arterial blood (ABG) for blood gas analysis. While there is a close agreement between ABG and CBGE/CBGF regarding pH and pCO2, pO2 is often underestimated by CBG. Recently, a software tool (v-TAC®; Roche Diagnostics, Risch-Rotkreuz, Switzerland) has been developed to calculate ABG values based on a peripheral venous blood gas analysis supplemented with peripheral oxygen saturation. OBJECTIVE: Here we investigate whether v-TAC can also be used to calculate ABG values from capillary blood samples. METHODS: Patients (n = 85) with an indwelling arterial line were included in the study. A reference ABG sample (ABG1) was obtained, followed by CBGE, CBGF, and finally a second ABG (ABG2). Results of CBGE/CBGF before and after mathematical arterialization by v-TAC (aCBGE/aCBGF) were compared to ABG1. RESULTS: After mathematical arterialization by v-TAC, the mean bias in pO2 between ABG1 and CBGE went down from 5.24 mm Hg (95% limit of agreement [95% LoA]: -14.19 to 24.67) to 0.18 mm Hg (95% LoA: -11.84 to 12.20) and was in a similar range as the mean bias between ABG1 and ABG2 (0.39 mm Hg [95% LoA: -13.46 to 14.24]). Differences in pH and pCO2 between arterial and capillary samples were small before and after mathematical arterialization. Very similar results were obtained when using fingertip instead of earlobe capillary blood. CONCLUSION: In summary, v-TAC can be used for mathematical arterialization of capillary blood samples for blood gas analysis resulting in increased diagnostic accuracy for pO2.

Performance Evaluation of the i-SmartCare 10 Analyzer and Method Comparison of Six Point-of-Care Blood Gas Analyzers.

Blood gas, electrolyte, glucose, and lactate level measurement have an immediate and critical impact on patient care. We evaluated the performance of i-SmartCare 10 (i-SENS Inc., Seoul, Korea) and conducted a method comparison study of five point-of-care (POC) analyzers with i-SmartCare 10 as the comparator, according to the CLSI guidelines. Ten analytes (pH, pCO2, pO2, Na+, K+, Cl-, iCa2+, glucose, lactate, and Hct) were tested on six analyzers: i-SmartCare 10, ABL90 FLEX PLUS (Radiometer Medical ApS, Copenhagen, Denmark), i-Stat (Abbott Point of Care Inc., Princeton, NJ, USA), RapidLab 1265 (Siemens Healthcare Diagnostics Inc., Tarrytown, NY, USA), Stat Profile pHOx Ultra (Nova Biomedical, Waltham, MA, USA), and Gem Premier 5000 (Instrumentation Laboratory, Bedford, MA, USA). The total imprecision and linearity (r2>0.99) were excellent, except for a few analytes that narrowly escaped the preset criteria. Interference was noted for Na+ in the presence of a high K+ level and for iCa2+ in the presence of high K+ and Mg2+ levels. Forty of 48 items demonstrated either a proportional or systematic difference in regression analysis; the relative mean difference (%) of 14/48 items escaped the allowable total error in the difference plot analysis. i-SmartCare 10 shows acceptable performance, and using a single POC blood gas analyzer is recommended for monitoring.

Hemolysis and blood gas analysis: it's time for a change!

Modern blood gas analyzers are not able to identify hemolysis, lipemia and icterus; therefore, the aim of this study was to assess the influence of hemolysis on blood gas samples. Blood gas analysis represents an essential part in the diagnosis and treatment of critically ill patients, including those affected by the pandemic coronavirus disease 2019 (COVID-19). Hemolysis, lipemia, and icterus, are causes of clinical misinterpretation of laboratory tests. A total of 1244 blood gas specimens were collected over a one-week period from different clinical wards, including the Emergency Department, and were assessed for serum indices on Cobas C6000 CE (Roche Diagnostics, Mannheim, Germany). The prevalence of hemolysis, lipemia, and icterus were 5%, 12%, and 14%, respectively. Sample storage at room temperature, delivery to central laboratory using pneumatic tube system, as well as small sample size, strongly affected blood gas parameters (p < .01). Hemolysis led to an increase in analytical bias for pH, pO2, and potassium, and a significant decrease for pCO2, HCO3-, sodium, and Ca2+ (p <.01). Currently, hemolysis detection systems are not yet widespread, and a rapid centrifugation of samples after blood gas analysis along with the assessment of serum indices represent the only prompt approach to identify unsuitable results, avoiding pitfalls in clinical decision-making, although it cannot be applied to the Emergency Department routine. Blood gas analyzers manufacturers and suppliers should implement automated built-in serum indices detection systems.