Blood Gas Analyzer Research Articles

Value of narcotrend anesthesia depth monitoring in predicting POCD in gastrointestinal tumor anesthesia block patients

BackgroundThe purpose of this research was to evaluate the efficacy of Narcotrend (NT) monitoring on cognitive dysfunction in patients undergoing anesthesia blockade for gastrointestinal tumors and its effect on cerebral oxygen metabolism and inflammatory response.MethodsPatients preparing to undergo resection of gastrointestinal tumor resection were included and randomly divided into a control group (depth of anesthesia assessed by physician experience) and a research group (depth of anesthesia monitored by NT). HR and MAP were monitored at the preoperatively (T0), 12 h postoperative (T1), 24 h postoperative (T2), and 48 h postoperative (T3) stages. MMSE score was recorded to assess changes in cognitive function. Intracerebral oxygenation indicators (CjvO2, CERO2, and rSO2) were assessed by a blood gas analyzer. ELISA assay was conducted to explore the serum inflammatory indexes (CRP, IL-1β, and TNF-α) and neurological function indicators (NSE and MBP).ResultsMAP was higher in the research group than in the control group at T1 and T2 (P < 0.05). MMSE scores at T1, T2, and T3 stages were higher in the research group than in the control (P < 0.05). The incidence of POCD was also lower in the research group compared with the control (P < 0.05). CjvO2, CERO2, and rSO2 were significantly higher (P < 0.05) and were positively correlated with the MMSE scores. Postoperative serum inflammatory indexes were significantly elevated in both groups, but more significantly in the control group (P < 0.05). Both neurological function indicators were usually reduced after surgery, but the reduction was more significant in the research group (P < 0.05).ConclusionNT monitoring of anesthetic depth has a less physical impact on patients with gastrointestinal tumor anesthetic block, reduces the degree of postoperative POCD, and has significant clinical value.

A-333 Comparison between measured total carbon dioxide and calculated bicarbonate in hospitalized patients

Abstract Background Bicarbonate (HCO3-) is a key indicator of anion excess or deficit and important clinically for assessing acid-base balance. For patient care, HCO3- may be reported as a calculated value from blood gas analysis or measured on automated chemistry analyzers. When measured, the final result includes HCO3-, carbonate (CO32-) and carbamino compounds and thus is reported as total CO2 (TCO2). Anecdotally, some patients have discrepancies between HCO3- and TCO2. However, there is limited data in the published literature assessing agreement between the two methods. Our study aims to compare the calculated HCO3- values with measured TCO2 obtained from simultaneously collected clinical specimens. Methods This study included all results from physician ordered HCO3- and TCO2 between 01/2019 to 12/2020 retrospectively retrieved from the laboratory information system (Cerner). Specimens were collected by nursing staff within 5 minutes of each other. TCO2 was assessed on a Roche cobas 702 (CV = 4.2%) according to the manufacturer’s instructions using an enzymatic phosphoenolpyruvate carboxylase method in lithium heparin tubes. HCO3- was calculated using a Radiometer ABL800 blood gas analyzer from arterial or venous blood gas samples according to the manufacturer’s instructions. Briefly, HCO3- is calculated using the Henderson-hasselbalch equation and the measurement of PCO2 (CV= 1.75%), and pH (CV = 0.06%). Deming regression was performed. The CLIA total allowable error of 4 mmol/L and a reference change value (RCV, Cv Individual = 4%) of -13 and + 14 for TCO2 was used to assess agreement. All data was analyzed in R. Results There were 101,895 paired HCO3- and TCO2 results during the study period. The values ranged from 4 to 56 mmol/L and the mean was 25.7. The mean difference between the calculated HCO3- and measured TCO2 was 1.33 mmol/L. Relative to HCO3-, there were 2,119 (2.1%) TCO2 results with a negative bias exceeding 4 mmol/L and 427 (0.4%)[FC1] with a positive bias exceeding 4 mmol/L. Twenty-two samples exceeded the positive RCV of 14% and 22 samples exceeded the negative RCV. Deming regression revealed a slope of 1.09 (95% CI: 1.087-1.092) an intercept of -2.19 (-2.18 to -2.06), and a Pearson correlation of 0.960 (0.959 to 0.960). We also analyzed differences between HCO3- and TCO2 in arterial and venous samples. The Pearson r for venous samples was 0.956 (0.955 to 0.957) and for arterial samples was 0.966 (0.966-0.966). Deming regression revealed a slope of 1.099 (0.195 to 1.104) and 1.071 (1.068 to 1.074) for venous and arterial samples respectively. The intercept for venous samples was -1.441 (-1.559 to -1.324) and for arterial was -2.005 (-2.072 to -1.938). Conclusions There is bias between HCO3- calculations and TCO2 measurements in simultaneously drawn samples. A small proportion of samples (2.5%) exceed the CLIA total allowable error between the results but very few exceed the RCV. This may due to differences in matrices, with different correlations and slopes observed between arterial and venous specimens. Further studies are required to distinguish the causes of the observed differences between HCO3- and TCO2.

A-324 Performance and Turnaround Time of Plasma Lactate Assay on POCT, Blood Gas Instrument, and Chemistry Analyzer

Abstract Background Time is a critical factor of plasma lactate testing in the management of patients with sepsis. To best serve these patients, we must optimize testing methods to provide a turnaround time (TAT) that guides efficient patient care. Point of care tests (POCTs) provide rapid results for emergency department and medical intensive care unit but are not feasible for all hospital settings. Laboratory testing methods on an automation line provide greater efficiency but result slowly due to need of specimen preparation and longer analytical time. The goal of this study is to provide detailed TATs of plasma lactate testing among the methods of POCT, chemistry analyzer in an automation line, and blood gas analyzer. Methods Plasma lactate testing was performed by three methods, GEM Premier ChemSTAT (POCT in ER only), Beckman AU5800 (chemistry analyzer), and Radiometer ABL800 (blood gas instrument). The TAT of lactate for each method was measured and include the time from specimen collection to laboratory receipt (except for POCT method), and time from specimen receipt to resulting (including specimen preparation for Beckman AU5800). Results The average TATs of lactate testing for each method in all hospital sites are detailed with respect to each event and subcategorized (Table 1). The average TAT of 12.0 min on Radiometer ABL800 is higher than the TAT of 2.5 on GEM Premier ChemSTAT method but is greatly reduced compared to the TAT of 35.4 min on Beckman AU5800. Conclusions Radiometer ABL800 method could be the optimal laboratory method for plasma lactate testing fulfilling the TAT (average 12 min), with less test cancellation due to specimen stability issue, and combines testing with blood gases. Using three Radiometer ABL800 instruments, we manage the performance of around 70 plasma lactate tests daily.

A-127 Stability of Ionized Calcium in Blood Gas Specimens

Abstract Background Ionized calcium monitoring is crucial for monitoring critically ill patients as well as patients undergoing apheresis. According to CLSI C31-A2:2001, the acceptable stability time for all tests to be run on blood gas analyzers in heparinized syringes is thirty minutes from collection. We sought to determine whether the stability of ionized calcium in blood gas samples can be extended to accommodate prolonged transport times. Methods Sixty whole blood samples were collected into 1CC syringes containing 23 IU of heparin (Vital Signs, Inc.) and sent to the laboratory for ionized calcium and pH analysis on the Siemens RAPIDLab 1265. If the remaining sample was sufficient, it was set aside for additional testing 40, 60 and 90 minutes after receipt in the laboratory. All samples were kept at room temperature during all timepoints. The three timepoints were compared to the initial reported baseline result and the average percent bias and standard deviation was determined. Results When compared to the baseline result, samples analyzed at the 40-, 60-, and 90-minute timepoints showed negligible bias for both pH and ionized calcium. The absolute bias was within +/- 0.6 and +/-0.4 for ionized calcium and pH, respectively. Conclusions This study showed that accurate measurements of both ionized calcium and pH can be obtained from blood gas samples collected in heparinized syringes at least till 90 minutes after collection.

A-343 Novel In-Line Hemolysis Detection on a Blood Gas Analyzer for Capillary Samples

Abstract Background Point-of-care (POC) blood gas and electrolyte analyzers utilizing whole blood as the predominant sample type are blinded by the presence of hemolysis until today. Moreover, capillary samples are particularly vulnerable to in-vitro hemolysis due to excessive force applied during sample collection. Here, we introduce the GEM Premier 7000 with iQM3 (GEM 7000) which incorporates automatic, in-line hemolysis detection in capillary blood gas samples without a need for additional sample volume or reagents. Methods The hemolysis detection module which is integrated into the disposable GEM cartridge uses acoustophoretic technology and photometric measurements to detect hemolysis in whole blood. In GEM 7000, hemolysis of ≥ 116 mg/dL was found to have significant interference with potassium results. A hemolysis flag is presented as the degree of hemolysis: none (0 - 50 and 51 - 115), mild (116 - 200 and 201 - 300), moderate (301 - 400), and gross (≥401). Due to volume limitations with native capillary samples and challenges in assessing hemolysis levels with a comparator assay, venous blood spiked volumetrically with hemolysate and transferred to capillary devices was used to verify the hemolysis flag performance. An agreement analysis was performed using the Roche cobas hemolysis value. The device's (GEM 7000) ability to flag hemolyzed capillary samples is demonstrated in a simulated clinical setting using native and contrived fingerstick capillary samples. Results Hemolysis verification with transferred capillary samples demonstrated that 98.2% (274/279) of samples were correctly flagged based on the cobas hemolysis value of spiked hemoglobin. Hemolysis in the native capillary samples (N = 235) was primarily distributed in the 0-50 mg/dL range. Additionally, native capillary samples altered using vigorous flea mixing (&amp;gt; 1 minute) showed hemolysis distribution over a wide hemolysis degree (none to gross), and their potassium results were flagged accordingly. Conclusions By providing integrated hemolysis detection in capillary blood sample measurements, the GEM Premier 7000 with iQM3 system can provide quality and confidence in the clinical interpretation of critical results such as potassium.

A-345 Effect of Hemolysis on Routine Blood Gas Analytes

Abstract Background Hemolysis is a major pre-analytical concern for most laboratory analytes. Detection of hemolysis and mitigation efforts are especially important for analytes, such as potassium, with high intracellular concentrations. Routine serum and plasma chemistry tests are performed on analyzers with the capacity to detect and measure the degree of hemolysis. However, for whole blood chemistries and blood gas measurements, the instruments utilized lack this capacity. The aim of this study was to evaluate the effect of hemolysis on whole blood and blood gas analytes and to compare visual assessments of hemolysis to measured hemolysis indices (H-index). Methods Remnant whole blood samples were split into two portions and each portion was aspirated and dispensed through a syringe one or more times. For the mock portion, only the syringe was used, while the hemolyzed portion had a needle affixed to the end of the syringe. The needle provided shear stress on the red blood cells to induce hemolysis, while the mock procedure was used to assess the impact of aspirating/dispensing on the sample in the absence of hemolysis. Each portion was then analyzed on a Radiometer ABL800 series instrument, spun down, and the H-index of the plasma portion was measured on a Roche cobas 8000 instrument. Medical technologists recorded their visual assessment of the specimens, with two technologists agreeing to the categorization of the specimen as either slightly, moderately, or severely hemolyzed. Degree of hemolysis was categorized by the delta (hemolyzed - mock) of the measured H-index: slight hemolysis was defined as an H-index delta of &amp;lt;100, moderate as 100-500 and severe as &amp;gt;500. Results The effect of hemolysis, with H-indices ranging from 2 to 3861, on 13 routine blood gas analytes was studied for 85 whole blood specimens. Hemolysis had little effect on metabolites, as percent bias was within ±3% at all levels of hemolysis for glucose, creatinine, and lactate. Similarly, most cooximetry components were minimally affected, with total hemoglobin, oxyhemoglobin, carboxyhemoglobin, and oxygen saturation within ±5% bias at all levels of hemolysis. Methemoglobin had a larger overall negative bias, with slight, moderate, and severe hemolysis levels yielding percent biases of -6.6, -12.3, and -13.3%, respectively. As expected, potassium displayed a significant positive bias with increasing hemolysis, with a generally linear trend. At moderate levels of hemolysis, the average potassium bias was 24.0% and at severe levels, over 100%. Sodium and ionized calcium also displayed overall linear trends but with a negative bias. At slight, moderate, and severe levels of hemolysis, sodium had a -0.56, -1.10, and -3.96% bias, and ionized calcium had a -2.99, -5.65, and -15.5% bias respectively. Conclusions Hemolysis can falsely increase or decrease a range of blood gas analytes and lead to misinterpretation of results and adversely affect clinical decision-making. Therefore, equipping current blood gas analyzers with hemolysis detection capabilities is crucial to enable laboratories to mitigate this effect and ensure accurate results for patient care.

A-340 Analysis of OrganOx Liver Perfusate at the Point-of-Care on the Abbott iSTAT and Nova Glucometer to Support Clinical Evaluations of Donor Livers Prior to Transplantation

Abstract Background The recently FDA-approved OrganOx Metra normothermic perfusion system for maintaining donor livers under physiologic conditions prior to transplantation comes equipped with a limited onboard blood gas analyzer for monitoring pO2, pCO2 and temperature. In clinical practice, however, additional biomarkers are used to assess the functional performance of the donor liver, including perfusate lactate clearance and glucose utilization. Liver perfusate contains a mixture of packed red blood cells, albumin, heparin, antibiotic, and solutions of amino acids and electrolytes and bile salts to support metabolic function, and is a specimen type that is not approved by the FDA. Implementation of the OrganOx Metra at Loyola University Medical Center (LUMC), a quaternary care transplant center, led to the validation of liver perfusate for the evaluation of glucose and lactate at the point-of-care (POC) using the Nova STATStrip Glucometer and Abbott iSTAT CG4 cartridge, respectively. Methods Lactate was measured on the Abbott iStat CG4 cartridge, and glucose which was measured using the Nova STATStrip Glucometer. Recovery studies were performed by mixing liver perfusate (non-centrifuged, n=16 independent specimen) with heparinized whole blood. Results The average recovery for the evaluation of lactate was 100% (range = 78 to 122%), and the average recovery for glucose was 109% (range = 93 to 112%). Conclusions Recovery studies evaluating matrix effect for the analysis of lactate (Abbott iSTAT, CG4) and glucose (Nova STATStrip) in liver perfusate indicate that the matrix of the perfusate does not affect the analytical accuracy, as compared to heparinized whole blood, the FDA-approved specimen type. Measurement of the OrganOx liver perfusate for lactate and glucose on these POC devices demonstrates reliable assessments to guide transplant teams in evaluating the viability of donor livers.

A-116 Pleural Fluid pH - Are We Collecting and Measuring It Correctly?

Abstract Background Pleural fluid pH has diagnostic, therapeutic, and prognostic implications in the management of pleural space infections and malignancy. Pleural fluid sample collection, transportation and processing are known for source of pre-analytical error which contribute to inaccuracy of measured pH with clinical implication to patient care. Some clinical practices observed locally include pleural fluid collection in sterile container for ease of other biochemistry analytes measurement in addition to pH. This study aimed to compare the differences in pleural fluid pH and other commonly ordered biochemistry analytes collected using sterile container against heparinized blood gas syringe. Methods Total 20 Pleural fluid samples were collected from patient using a procedure called thoracentesis from, with approximately 2 to 3ml of fluid directly transferred into heparinized blood gas syringe as well as in a sterile container. Both samples were then transported to Clinical Biochemistry Laboratory within an hour. Both samples were analyzed on 3 analytical systems; 1) pH on Roche COBAS b221 blood gas analyzer, 2) Glucose, Total Protein, LDH on Beckman AU System and 3) Specific Gravity on Reflectometer. Statistical analysis was performed using Analyze-It software. Results pH fluid collected in sterile container demonstrates significant high bias (absolute of 0.4 units or 5%) as compared to sample collected in heparinizes blood gas syringe. Other commonly ordered tests in fluid profile (Glucose, Total Protein, LDH and SG) demonstrate good correlation (Altman-Bland Difference Plot &amp;lt;5%) for pleural fluid collected in sterile container as compared to heparinized syringe. Conclusions This positive bias observed is likely attributed to air exposure in pleural fluid collection in sterile container as compared to heparinized syringe. The accuracy of measured pleural pH is critically dependent on the method of sample collection. This study highlights the need for a standardized protocol for pleural pH collection for accurate measurement.

A-362 Hemolysis Detection and Flagging of Potassium Results on GEM Premier 7000 with iQM3

Abstract Background Blood gas analyzers that report whole blood potassium (K+) are vulnerable to inaccurate results due to in vitro hemolysis. GEM Premier 7000 with iQM3 (GEM 7000) automatically detects hemolysis (plasma free hemoglobin) and flags impacted K+ results. Here, we report the hemolysis impact on K+ measurements and the flagging approach used in the GEM 7000 system. Methods Hemolysis interference was assessed according to CLSI EP07c at low (3.8 mmol/L) and high (5.3 mmol/L) K+ levels. Ultrasonically-lysed whole blood was used to generate a high test pool (100% = 1000 mg/dL hemoglobin). This was mixed volumetrically with a low pool (0% = native blood) to create additional test pools (25%, 50%, and 75%) and analyzed on three (3) GEM 7000 systems. K+ bias at each test pool was calculated from the low pool to generate hemolysis interferograms. Linear regression was performed to determine the hemolysis level that exceeds the interference limit of 7%. Results Hemolysis exceeding the interference limit was ≥ 116 mg/dL for the low K+ and ≥ 147 mg/dL for the high K+ level. These correspond to an elevation of 0.27 mmol/L and 0.37 mmol/L of K+, respectively. Based on this study, the GEM 7000 triggers a hemolysis flag when the detected hemolysis exceeds 115 mg/dL. By default, GEM 7000 hemolysis flags are categorized into mild (116 -300 mg/dL), moderate (301 - 400 mg/dL), and gross (≥401 mg/dL) hemolysis. Conclusions The magnitude of the observed increase in K+ (0.277 - 0.295 mmol/L for every 100 mg/dL of hemoglobin) on the GEM 7000 due to in vitro hemolysis is consistent with previously published reports in the literature. Automated hemolysis detection and flagging of K+ results in GEM 7000 overcome the limitation of the inability to detect hemolysis in blood gas samples.

A-358 Extended linearity studies for pO2, pCO2, K+ Cl- on GEM 5000 blood gas analyzers using a combination of verification materials

Abstract Background Blood gas analyzers (BGA) measure blood gases pO2,pCO2,O2Hb,COHb,MetHb, and several analytes in the workup and management of acid-base disorders. GEM 5000 BGA (Instrumentation Laboratory, a Werfen Company) have very broad reportable ranges for the measured analytes. However, manufacturer’s current linearity materials do not cover the entire reportable ranges claims. This poses challenge to clinical laboratories, especially for pO2 and pCO2 to comply with College of American Pathologists (CAP) requirements to verify instruments performance every six months through the entire reportable range. We evaluated secondary materials in combination with manufacturer’s primary linearity materials for pO2, pCO2, K+ and Cl- for an extended linearity verification. Methods Routine linearity studies was performed with PVP (5-levels), a primary material provided by the GEM 5000 analyzer manufacturer. Hypoxic (pO2: 5-25mmHg) and hyperbaric (pO2: 600-670mmHg) materials obtained from Eurotrol Inc. and VK-R5 linearity material (Radiometer America Inc.) for pCO2, K+ and Cl- were processed on GEM 5000. All materials at all levels were assayed in duplicate. Results from PVP, Eurotrol and VK-R5 were combined from low to high levels to assess linearity verification. Results Linearity range of 15-630mmHg with r2=0.99 was verified for pO2. Using a combination of VK-R5 with PVP, a linearity range of 14-127 mmHg (r2=0.99) for pCO2, 1.1-14.1 mmol/L (r2=1.00) for K+, and 51-153 mmol/L (r2=1.00) for Cl-were verified. See table for details. Conclusions A combination of BGA manufacturer’s primary linearity material with secondary vendors material was useful in addressing linearity verification for blood gases pO2, pCO2, and electrolytes K+Cl- over an extended range close to the manufacturer’s claims. We recommend other laboratories that experience similar BGA linearity verification challenges to consider this approach for verification of the manufacturer’s claims. It would have been very helpful if manufacturer can provide materials that cover both the lower and upper limits of their claims.

Comparison of Blood-Gas Hemoglobin and Electrolyte Measurements and Automated Laboratory Values in Pediatric Kidney Transplant Patients.

The reliability of blood-gas measurements compared with automated laboratory tests in providing rapid results for pediatric patients is currently under investigation. The compatibility between fast-response blood-gas tests and standard automatic laboratory tests remains a subject of debate. In this retrospective single-center study, our objective was to compare the measurements of hemoglobin and electrolytes obtained through blood-gas analysis with the corresponding values obtained from standard laboratory tests in pediatric renal transplantation, specifically focusing on the immediate pretransplant period. We retrospectively investigated 26 pediatric kidney transplant patients in the pretransplant period. We reviewed their medical records and compared and simultaneous measurements of hemoglobin, sodium, and potassium from a blood-gas analyzer versus a laboratory automatic analyzer. We assessed the agreement between the 2 analyses with BlandAltman analysis and Cohen kappa statistic. Among the 26 pediatric kidney transplant recipients, mean age was 10.1 ± 4.9 years and 60.0% were male patients. The mean differences between blood-gas and the venous laboratory analyzer (95% CI) were as follows: 0.11 g/dL for hemoglobin (-0.27 to 0.05 g/dL; P > .05), 0.39 mEq/L for sodium (-0.58 to 1.35 mEq/L; P > .05), and 0.00 mEq/L for potassium (-0.25 to 0.25 mEq/L; P > .05). Cohen kappa test showed the highest agreement for sodium, with no significant difference in mean values. Our study demonstrated strong agreement between hemoglobin, sodium, and potassium values obtained through blood-gas measurements and venous blood samples in pediatric kidney transplant recipients. Demonstrating the concordance between rapid blood-gas analysis and automated laboratory tests can offer valuable guidance to clinicians.

Calcium propionate is an alkalizing agent in exercising Standardbreds.

The objective of this study was to determine if calcium propionate is an alkalizing agent in exercising Standardbreds and if it alters plasma glucose and serum insulin concentrations. This study used a randomized crossover design to test the hypotheses that calcium propionate alters total CO2 (tCO2), Ca++, pH, strong ion difference (SID), glucose, and insulin in Standardbreds completing a simulated race test (SRT) on a high-speed equine treadmill. Blood was collected from eight horses (mean age ± SD = 16 ± 2.7 years; range = 13 - 21 years) at 10 and 5 min prior to treatment or control administration, just prior to the subsequent SRT, directly after the SRT, and at 60- and 90-min post SRT. Plasma pH and plasma concentrations of tCO2, glucose, Ca++, and Na+, K+, Cl-, Lac- (for SID calculation) were measured in duplicate by blood gas analyzer and serum insulin by radioimmunoassay. Data were analyzed by two-way repeated-measures ANOVA. For plasma pH, Na+, K+, Cl-, Lac-, SID, insulin and glucose, no effects of treatment or treatment by sampling-timepoint interaction were found (p>0.05). Plasma tCO2, Ca++, pH, Na+, SID, and glucose concentrations were significantly lower, and Lac- was significantly higher, directly after the SRT compared to all other timepoints (p<0.05). Plasma tCO2, HCO3- and Ca++ were significantly higher in treated than in control horses at multiple sampling timepoints after treatment/control administration (p<0.05). Serum insulin concentration, measured only pre and 30 min post treatment/control administration, was unaffected by treatment. Calcium propionate is an alkalizing agent in horses.

Novel In-Line Hemolysis Detection on a Blood Gas Analyzer and Impact on Whole Blood Potassium Results.

Preanalytical error due to hemolyzed blood samples is a common challenge in laboratory and point-of-care (POC) settings. Whole blood potassium (K+) measurements routinely measured on blood gas analyzers are particularly susceptible to hemolysis, which poses a risk for incorrect K+ results. The GEM Premier 7000 with IQM3 (GEM 7000) blood gas analyzer provides novel integrated hemolysis detection within the sample measurement process. Therefore, the GEM 7000 can detect and flag hemolyzed whole blood samples at the POC, warning the operator of potentially erroneous results. Heparinized venous or arterial whole blood samples were used for K+ interference studies and assessed for hemolysis agreement utilizing either a traditional volumetric method or chemistry analyzer serum index measurements with the Roche cobas c311 or Abbott Alinity c. Hemolysis interference studies performed at 2 different K+ concentrations (3.8 and 5.3 mmol/L) identified that a plasma free hemoglobin ≥116 mg/dL can impact K+ results on the GEM 7000. Hemolysis agreement studies demonstrated an excellent agreement of >99% with the volumetric method, 98.8% with cobas H index, and 96.4% with Alinity H index. GEM 7000 K+ results were correctly flagged for both native and spiked samples. GEM 7000 hemolysis detection provides a novel technology to detect hemolysis in whole blood samples. Moreover, the GEM 7000 demonstrates excellent agreement with traditional laboratory hemolysis detection methods and offers an integrated technological solution for assuring the quality of whole blood K+ results in POC settings.

Early Operative Risk Assessment Using the Modified Mannheim Peritonitis Index in Patients With Generalised Peritonitis at a Tertiary Hospital in Abuja, Nigeria.

Introduction The use of validated prognostic scoring tools in resource-poor environments has been hampered by the cost of procuring and maintaining devices, such as arterial blood gas analysers, to measure critical physiological derangements.Attempts need to be made to adapt these applicable risk stratification tools so they can be easily adopted in developing countries like Nigeria. Aim This study assessed the usefulness of a modified Mannheim peritonitis index (mMPI) as arisk stratification tool in predicting surgical outcomes in managing patients with generalised peritonitis in Abuja, Nigeria. Methods This was a prospective study of consecutive adult patients managed for generalised peritonitis at a tertiary hospital in Abuja over 12 months. Approval numbers NHA/EC/037/2019 and AF/013/17/110/1514 were ascribed to the project by the Institute Review Board Committee (IBR) of the National Hospital Abuja (NHA) and the National Postgraduate Medical College of Nigeria. The MPI was modified using respiratory rate and suboptimal percentage oxygen saturation (SpO2). Patient characteristics and treatment outcomes obtained were entered into a structured proforma, checked, and analysed using IBM SPSS Statistics for Windows, Version 25.0 (Released 2017; IBM Corp., Armonk, New York, United States). The threshold score of the modified MPI and the accuracy, sensitivity, and specificity were derived from the receiver operating characteristic (ROC) curve analysis and its coordinates. The level of statistical significance was set at a p-value of <0.05. Results There were 49 patients with generalised peritonitis during the study period with a male-to-female ratio of 2.5:1. The commonest cause of peritonitis in this study was penetrating abdominal injury (n=15, 30.6%), followed by complicated appendicitis (n=12, 24.5%). This study's mortality and morbidity rates were 14.3% and 63.3%, respectively. On the ROC curve, the modified MPI best predicts mortality at a threshold score point of ≥26 (accuracy of 79.4%, sensitivity of 85.7%, specificity of 61.9%, p=0.013) and morbidity at a threshold score of ≥23 (accuracy of 78.4%, sensitivity of 77.4%, specificity of 72.2%, p=0.001). Conclusion The modified MPI can be used as a risk assessment tool to predict postoperative outcomes in adult patients operated on for generalised peritonitis within 30 days of operative intervention at Abuja.This modification may be helpful in low-resource centres with limited access to arterial blood gas analysers. However, the original MPI might be a more accurate tool.

FP7.18 - Early Operative Risk Assessment Using Modified Mannheim Peritonitis Index in Patients with Generalised Peritonitis at a Tertiary Hospital in Abuja, Nigeria

Abstract Aim This study assessed the usefulness of a modified Mannheim Peritonitis Index (MPI) as a risk stratification tool in predicting surgical outcomes in the management of patients with generalized peritonitis in Abuja, Nigeria. Methods This is a prospective study of consecutive adult patients managed for generalized peritonitis at a tertiary hospital in Abuja Nigeria within a one-year duration. The MPI was modified using respiratory rate and SpO2. Patient characteristics and outcome of treatment obtained were entered into a structured proforma, checked and analysed using the SPSS, version 25. The threshold score of the modified MPI, as well as the accuracy, sensitivity, and specificity, were derived from the receiver-operator characteristic (ROC) curve analysis and its coordinates. Results There were 49 patients with generalised peritonitis during the study period with a male-to-female ratio of 2.5:1. The commonest cause of peritonitis in this study was penetrating abdominal injury (30.6%) followed by complicated appendicitis (24.5%). This study's mortality and morbidity rates were 14.3% and 63.3%, respectively. On the ROC curve, the modified MPI best predict mortality at a threshold score point of ≥26 (Accuracy of 79.4%, sensitivity of 85.7% specificity of 61.9%, P-value = 0.013), and morbidity at a threshold score of ≥23 (Accuracy 78.4%, sensitivity of 77.4%, specificity of 72.2%, P-value = 0.001). Conclusion The modified MPI can be used as a risk assessment tool in predicting postoperative outcomes in adult patients operated for generalised peritonitis within 30 days of operative intervention at Abuja. This modification can be useful in low-resource centres with limited access to arterial blood gas analysers.

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.

Combined Lactate Glucose Ratio as a Novel Marker for Rapid Diagnosis of Cerebrospinal Fluid Bacterial Infection in Neurosurgical Patients: Diagnostic Accuracy Study and Benchtop Analyzer Correlation

ObjectiveThis study aimed to assess the diagnostic accuracy of a novel marker, the combined lactate-to-glucose ratio (CLGR), in identifying cerebrospinal fluid (CSF) bacterial infection (CBI) in neurosurgical patients. Additionally, it seeks to establish cut-off values for CLGR and evaluate the reliability of measurement using blood gas analyzer (BGA). MethodsCSF samples were collected from two neurosurgical centers in Kuala Lumpur, Malaysia, between January 2022 and October 2023. Conventional markers and CLGR were quantified using standard laboratory methods, with BGA utilized for measurement when feasible. Samples were categorized into confirmed CBI-positive (CBI+) and CBI-negative (CBI-) groups. Marker performance was compared, and receiver operating characteristic analysis conducted. Pearson's correlation assessed the agreement between BGA and laboratory measurements. ResultsAmong the 130 CSF samples, 11 were CBI+. Both cLac and CLGR were significantly elevated in the CBI+ group (p<0.001). The area under the curve (AUC) for cLac and CLGR was 0.990 and 0.994, respectively. Using a cut-off of 6.0mmol/L, cLac demonstrated sensitivity of 100%, specificity of 93.3%, positive predictive value (PPV) of 57.9%, negative predictive value (NPV) of 100%, and diagnostic accuracy of 93.9%. CLGR ≥20.0 showed even higher accuracy: 100.0% sensitivity, 98.6% specificity, 84.6% PPV, 100% NPV, and overall accuracy of 98.5%. Both markers maintained excellent performance in blood-stained CSF. BGA measurements correlated well with laboratory results (r=0.980 & 0.999, respectively, p<0.001). ConclusionsCLac levels ≥6.0mmol/L and CLGR ≥20.0 accurately identified CBI in neurosurgical patients, with CLGR exhibiting superior efficacy. The potential for instant BGA measurement suggests promise for point-of-care testing.

Abstract P118: Effect of renal denervation on the blood pressure and progression of diabetic kidney disease in T2DN rats

Background: As a common complication of diabetes, diabetic kidney disease (DKD) is a chronic progressive disorder that can lead to kidney failure, and it is currently the leading cause of kidney replacement therapy in the USA and worldwide. Although renal denervation (RDNx) has recently been approved by the FDA to treat hypertension, contradictory findings have been reported on the effect of RDNx on the blood pressure and progression of DKD in type 2 diabetic mellitus. Here, we used type 2 diabetic nephropathy (T2DN) rats, a well-established non-obese model that displays similar renal abnormalities and hyperglycemic levels as seen in humans, to evaluate the effect of RNDx on the blood pressure and progression of DKD. Methods: Bilateral RDNx or sham surgeries were performed on male T2DN rats with mild and severe stages of DN (~20 or &gt;35 weeks old). The blood pressure was monitored chronically using radio telemetry throughout the entire experiment. 24-hr urine collection, glucose tolerance test, and GFR measurement were performed at baseline and at the end of the experiments. Blood and urine electrolytes were measured using a blood gas analyzer. The amount of norepinephrine in the kidney was evaluated by ELISA. Results: Bilateral RNDx were successfully performed on T2DN rats with a significant reduction of norepinephrine in the kidneys of the RDNx group (244±13 vs. 8±1 pg/mg for &gt;35 weeks old rats). The mean arterial pressure (MAP) and heart rate remain the same between the Sham and RDNx groups. The glucose tolerance test also indicates no difference between the two groups. While there is a significant decrease in the GFR in Sham group from baseline to week 3, the GFRs between Sham and RDNx groups are not different. Similarly, total body weight, kidney to total body weight ratio, heart to total body weight ratio, and blood and urine electrolytes are also not different between Sham and RDNx groups. Analysis of the younger group (~20 weeks old) is in progress. Conclusion: In summary, our data suggests that RDNx does not affect the blood pressure and progression of DKD in male T2ND rats, at least at the stage of severe kidney injury (&gt;35 weeks old). Funding sources: National Institute of Health R01 DK135644 and R01 DK129227, Department of Veterans Affairs I01 BX004024 (to AS), and APS Postdoctoral fellowship (to BX).

Short-Term Effects of Heat Stress on Cow Behavior, Registered by Innovative Technologies and Blood Gas Parameters.

Heat stress (HS) is one of the key factors affecting an animal's immune system and productivity, as a result of a physiological reaction combined with environmental factors. This study examined the short-term effects of heat stress on cow behavior, as recorded by innovative technologies, and its impact on blood gas parameters, using 56 of the 1070 cows clinically evaluated during the second and subsequent lactations within the first 30 days postpartum. Throughout the experiment (from 4 June 2024 until 1 July 2024), cow behavior parameters (rumination time min/d. (RT), body temperature (°C), reticulorumen pH, water consumption (L/day), cow activity (h/day)) were monitored using specialized SmaXtec boluses and employing a blood gas analyzer (Siemens Healthineers, 1200 Courtneypark Dr E Mississauga, L5T 1P2, Canada). During the study period, the temperature-humidity index (THI), based on ambient temperature and humidity, was recorded and used to calculate THI and to categorize the data into four THI classes as follows: 1-THI 60-63 (4 June 2024-12 June 2024); 2-THI 65-69 (13 June 2024-18 June 2024); 3-THI 73-75 (19 June 2024-25 June 2024); and 4-THI 73-78 (26 June 2024-1 July 2024). The results showed that heat stress significantly reduced rumination time by up to 70% in cows within the highest THI class (73 to 78) and increased body temperature by 2%. It also caused a 12.6% decrease in partial carbon dioxide pressure (pCO2) and a 32% increase in partial oxygen pressure (pO2), also decreasing plasma sodium by 1.36% and potassium by 6%, while increasing chloride by 3%. The findings underscore the critical need for continuous monitoring, early detection, and proactive management to mitigate the adverse impacts of heat stress on dairy cow health and productivity. Recommendations include the use of advanced monitoring technologies and specific blood gas parameter tracking to detect the early signs of heat stress and implement more timely interventions.

New spin coated multilayer lactate biosensor for acidosis monitoring in continuous flow assisted with an electrochemical pH probe

A LOx-based electrochemical biosensor for high-level lactate determination was developed. For the construction of the biosensor, chitosan and Nafion layers were integrated by using a spin coating procedure, leading to less porous surfaces in comparison with those recorded after a drop casting procedure. The analytical performance of the resulting biosensor for lactate determination was evaluated in batch and flow regime, displaying satisfactory results in both modes ranging from 0.5 to 20 mM concentration range for assessing the lactic acidosis. Finally, the lactate levels in raw serum samples were estimated using the biosensor developed and verified with a blood gas analyzer. Based on these results, the biosensor developed is promising for its use in healthcare environment, after its proper miniaturization. A pH probe based on common polyaniline-based electrochemical sensor was also developed to assist the biosensor for the lactic acidosis monitoring, leading to excellent results in stock solutions ranging from 6.0 to 8.0 mM and raw plasma samples. The results were confirmed by using two different approaches, blood gas analyzer and pH-meter. Consequently, the lactic acidosis monitoring could be achieved in continuous flow regime using both (bio)sensors.