Oxygenation saturation index in neonatal hypoxemic respiratory failure.

BACKGROUND: This study aimed to assess the validity of the oxygenation saturation index (OSI) and the ratio of oxygen saturation to the fraction of inspired oxygen (FIO2) (S/F ratio) with percutaneous oxygen saturation (OSISpO2 and the Sp/F ratio) and to evaluate the correlation between these values and the oxygen index (OI). It also determined their cut-off values for predicting OI in accordance with neonatal hypoxic respiratory failure severity. METHODS: We reviewed the data of 77 neonates (gestational age 31.7 ± 6.1 weeks; birthweight, 1768 ± 983 g) requiring invasive mechanical ventilation between 2013 and 2020, 1233 arterial blood gas samples in total. We calculated the OI, OSISpO2, OSI with arterial oxygen saturation (SaO2) (OSISaO2), Sp/F ratio, and the ratio of SaO2 to FIO2 (Sa/F ratio). RESULTS: The regression and Bland-Altman analysis showed good agreement between OSISpO2 or the Sp/F ratio and OSISaO2 or the Sa/F ratio. Although a significant positive correlation was found between OSISpO2 and OI, OSISpO2 was overestimated in SpO2 > 98% with a higher slope of the fitted regression line than that below 98% of SpO2. Furthermore, receiver-operating characteristic curve analysis using only SpO2 ≤ 98% samples showed that the optimal cut-off points of OSISpO2 and the Sp/F ratio for predicting OI were: OI 5, 3.0 and 332; OI 10, 5.3 and 231; OI 15, 7.7 and 108; OI 20, 11.0 and 149; and OI 25, 17.1 and 103, respectively. CONCLUSION: The cut-off OSISpO2 and Sp/F ratio values could allow continuous monitoring for oxygenation changes in neonates with the potential for wider clinical applications.

[Design of Pulse and Respiratory Signals Detection System].

A pulse and respiration synchronous detection system is designed to explore the changes of physiological signals in different situations. The system obtains the corresponding signal through STM32 control pulse and respiratory acquisition circuit, calculates and displays real-time parameters such as heart rate and respiratory rate, and transmits the data to the upper computer for storage in the database. The experimental test results show that the system can monitor pulse and respiratory waveform in different situations, and the waveform is in good condition. Compared with medical pulse oximeter, the error of measured heart rate and blood oxygen concentration is less than 3%, and the error of respiratory rate is less than 5% compared with the actual value, which verifies the accuracy of system signal acquisition. The system is small in size, low in cost, and comfortable to wear, and can be applied in experimental research related to pulse and respiratory signals.

Characteristics of pulse oximetry and arterial blood gas in patients with fibrotic interstitial lung disease.

BACKGROUND: Fibrotic interstitial lung disease (ILD) is frequently associated with abnormal oxygenation; however, little is known about the accuracy of oxygen saturation by pulse oximetry (SpO2) compared with arterial blood gas (ABG) saturation (SaO2), the factors that influence the partial pressure of carbon dioxide (PaCO2) and the impact of PaCO2 on outcomes in patients with fibrotic ILD. STUDY DESIGN AND METHODS: Patients with fibrotic ILD enrolled in a large prospective registry with a room air ABG were included. Prespecified analyses included testing the correlation between SaO2 and SpO2, the difference between SaO2 and SpO2, the association of baseline characteristics with both the difference between SaO2 and SpO2 and the PaCO2, the association of baseline characteristics with acid-base category, and the association of PaCO2 and acid-base category with time to death or transplant. RESULTS: A total of 532 patients with fibrotic ILD were included. Mean resting SaO2 was 92±4% and SpO2 was 95±3%. Mean PaCO2 was 38±6 mmHg, with 135 patients having PaCO2 <35 mmHg and 62 having PaCO2 >45 mmHg. Correlation between SaO2 and SpO2 was mild to moderate (r=0.39), with SpO2 on average 3.0% higher than SaO2. No baseline characteristics were associated with the difference in SaO2 and SpO2. Variables associated with either elevated or abnormal (elevated or low) PaCO2 included higher smoking pack-years and lower baseline forced vital capacity (FVC). Lower baseline lung function was associated with an increased risk of chronic respiratory acidosis. PaCO2 and acid-base status were not associated with time to death or transplant. INTERPRETATION: SaO2 and SpO2 are weakly-to-moderately correlated in fibrotic ILD, with limited ability to accurately predict this difference. Abnormal PaCO2 was associated with baseline FVC but was not associated with outcomes.

Exposure to Non-Steady-State Oxygen Is Reflected in Changes to Arterial Blood Gas Values, Prefrontal Cortical Activity, and Systemic Cytokine Levels.

Onboard oxygen-generating systems (OBOGSs) provide increased inspired oxygen (FiO2) to mitigate the risk of neurologic injury in high altitude aviators. OBOGSs can deliver highly variable oxygen concentrations oscillating around a predetermined FiO2 set point, even when the aircraft cabin altitude is relatively stable. Steady-state exposure to 100% FiO2 evokes neurovascular vasoconstriction, diminished cerebral perfusion, and altered electroencephalographic activity. Whether non-steady-state FiO2 exposure leads to similar outcomes is unknown. This study characterized the physiologic responses to steady-state and non-steady-state FiO2 during normobaric and hypobaric environmental pressures emulating cockpit pressures within tactical aircraft. The participants received an indwelling radial arterial catheter while exposed to steady-state or non-steady-state FiO2 levels oscillating ± 15% of prescribed set points in a hypobaric chamber. Steady-state exposure to 21% FiO2 during normobaria produced arterial blood gas values within the anticipated ranges. Exposure to non-steady-state FiO2 led to PaO2 levels higher upon cessation of non-steady-state FiO2 than when measured during steady-state exposure. This pattern was consistent across all FiO2 ranges, at each barometric condition. Prefrontal cortical activation during cognitive testing was lower following exposure to non-steady-state FiO2 >50% and <100% during both normobaria and hypobaria of 494 mmHg. The serum analyte levels (IL-6, IP-10, MCP-1, MDC, IL-15, and VEGF-D) increased 48 h following the exposures. We found non-steady-state FiO2 levels >50% reduced prefrontal cortical brain activation during the cognitive challenge, consistent with an evoked pattern of neurovascular constriction and dilation.

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.

Venous blood gases and electrolyte values of captive red foot tortoise (Chelonoidis carbonarius).

Blood gas analysis reflects the exchange of oxygen and carbon dioxide in the lungs. This test provides important information, since the relationship between these gases has a direct impact on the acid-basic balance in the body. Given the significance of blood gas analysis in Brazilian reptiles, this study set out to establish temperature-corrected and uncorrected reference intervals for venous blood gas measurements in Chelonoidis carbonarius, and to compare values between females and males. In this study, 19 animals were used, 8 males and 11 females. Blood samples were collected from the dorsal coccygeal vein, and the analyses were performed immediately after blood sample collection. The following parameters were measured: pH, PO2, HCO3-, TCO2, BEecf, Na, K, ICa, and Glu, and were compared between females and males. Additionally, pH, pCO2, and pO2 values were compared with and without temperature correction. Oxygen saturation and Na levels were significantly higher (p<0.05) in males. Furthermore, it was possible to infer that the lower the body temperature relative to the environmental temperature, the larger the difference in pH following temperature correction.

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.

Arterial blood gas analysis predicts futile recanalization in mechanical thrombectomy-treated acute ischemic stroke patients: a multicenter study.

OBJECTIVE: It is known that providing recanalization alone in large vessel occlusions is not sufficient to provide a good 90-day clinical outcome. It is advocated that neuroprotection should be increased before endovascular treatment and that the penumbra should be protected from reperfusion damage after recanalization. However, the effects of blood gas parameters before and after mechanical thrombectomy on clinical outcomes are not clear. The objective of this study is to assess the effectiveness of serial blood gas measures in accurately predicting futile recanalization at an early stage. PATIENTS AND METHODS: This study is a multicenter inquiry that collected data in a prospective manner and analyzed it retrospectively. Patients with a 2b-3 thrombolysis in cerebral infarction (TICI) score after mechanical thrombectomy for recanalization were consecutively analyzed from July 2022 to March 2023. Arterial blood gas parameters, including pH, oxygen saturation (SaO2), partial carbon dioxide pressure (PaCO2), partial oxygen pressure (PaO2), lactate, and bicarbonate (HCO3), were measured at four time points: before mechanical thrombectomy treatment (preoperative), immediately after recanalization (postoperative 1st), during the 3rd hour (postoperative 3rd), and at the 5th hour (postoperative 5th). The patients were categorized into groups based on their modified Rankin Scale (mRS) scores. RESULTS: The study included 136 patients with an average age of 69.71±11.22. The postoperative 1st-hour SaO2 values were lower in the mRS 3-6 group (p=0.038). The postoperative pH and lactate mean were greater in the mRS 3-6 group than in the 0-2 group (p=0.038 and 0.018, respectively). In logistic regression, a unit rise in lactate increased poor functional outcomes 1,632 times (p=0.024). Early neurological recovery was associated with decreased postoperative 3rd-hour lactate (p=0.014). The mean postoperative PaO2 (average of 1, 2, 3 PaO2) was higher in those with symptomatic cerebral bleeding (p=0.044). CONCLUSIONS: Monitoring lactate and pH levels in AIS patients who have had mechanical recanalization can be utilized to predict mortality and morbidity, especially in the first five hours after the procedure. Graphical Abstract: https://www.europeanreview.org/wp/wp-content/uploads/Graphical-abstract-8.jpg.

First Family Case of Hemoglobinopathy Titusville in China with Falsely Low SpO2 and Unmeasurable SaO2.

BACKGROUND: Normal hemoglobin is a tetrameric structure, consisting of two alpha-globin chains and two nonalpha (beta, gamma, delta) chains. Hemoglobinopathies occur when the presence of gene mutations affect the molecular structure or expression of the globin chains. METHODS: We reported the case of a 9-year-old Chinese girl who presented with abnormal low oxygen saturation values on pulse oximetry and no oximetry results were obtained during blood gas analysis (BGA). RESULTS: High-performance liquid chromatography (HPLC) and capillary electrophoresis demonstrated that the presence of a low oxygen affinity hemoglobin variant, characterized as hemoglobin Titusville, was proven by gene sequencing. The patient's mother and aunt also carry the hemoglobin variant, representing the first Chinese family case reported. CONCLUSIONS: Hemoglobin Titusville is a rare genetic hemoglobin structural defect. early diagnosis can help patients and clinicians avoid unnecessary anxiety and costly or excessive clinical investigations.

Arterial blood gas measurements are different for brachycephalic and nonbrachycephalic dogs acclimatized to an altitude of 1,535 meters.

OBJECTIVE: To define reference intervals (RIs) for arterial blood gas (aBG) measurements in healthy, nonsedated, dolichocephalic, and mesocephalic (nonbrachycephalic) dogs at approximately 1,535 m above sea level and compare these findings with healthy, nonsedated, brachycephalic dogs living at the same altitude. ANIMALS: 120 adult nonbrachycephalic dogs and 20 adult brachycephalic dogs. METHODS: Cases were prospectively enrolled from October 2021 to June 2022. Dogs were enrolled from the community or after presentation for wellness examinations or minor injuries including lacerations, nail injuries, and lameness. Physical examinations and systolic blood pressure (sBP) measurements were obtained before blood sample collection. Arterial blood was collected from the dorsal pedal artery or femoral artery. After data collection, brachycephalic dogs underwent pre- and postexercise tolerance assessments. RESULTS: The mean and RI values for arterial pH (7.442; 7.375 to 7.515), partial pressure of oxygen in arterial blood (Pao2; 78.3; 59.2 to 92.7 mm Hg), partial pressure of carbon dioxide in arterial blood (Paco2; 28.0; 21.5 to 34.4 mm Hg), saturation of arterial oxygen (Sao2; 98.4; 84.3% to 101.4%), HCO3 (18.9; 14.9 to 22.4 mmol/L), concentration of total hemoglobin (ctHb; 17.5; 13.4 to 21.1 g/dL), and sBP (133; 94 to 180 mm Hg) were established for healthy nonbrachycephalic dogs at 1,535-m altitude. All aBG measurements were statistically and clinically different from those previously reported for dogs at sea level. Brachycephalic dogs had significantly lower Pao2 and Sao2 (P = .0150 and P = .0237, respectively) and significantly higher ctHb (P = .0396) compared to nonbrachycephalic dogs acclimatized to the same altitude; the nonbrachycephalic RIs were not transferable to the brachycephalic dogs for Pao2. CLINICAL RELEVANCE: This study represents the first collation of aBG measurements for healthy nonbrachycephalic dogs acclimatized to an altitude of 1,535 m. Additionally, this study identified differences in arterial oxygenation measurements between brachycephalic and nonbrachycephalic dogs. RIs in brachycephalic dogs need to be established.

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.

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.

Feasibility and accuracy of noninvasive continuous hemoglobin monitoring using transesophageal photoplethysmography in porcine model.

BACKGROUND: Continuous and noninvasive hemoglobin (Hb) monitoring during surgery is essential for anesthesiologists to make transfusions decisions. The aim of this study was to investigate the feasibility and accuracy of noninvasive and continuous Hb monitoring using transesophageal descending aortic photoplethysmography (dPPG) in porcine model. METHODS: Nineteen landrace pigs, aged 3 to 5 months and weighing 30 to 50 kg, were enrolled in this study. A homemade oximetry sensor, including red (660 nm) and infrared (940 nm) lights, was placed in the esophagus for dPPG signal detection to pair with the corresponding reference Hb values (Hbi-STAT) measured by blood gas analysis. The decrease and increase changes in Hb concentration were achieved by hemodilution and transfusion. Metrics, including alternating current (AC), direct current (DC), and AC/DC for both red and infrared light were extracted from the dPPG signal. A receiver operating characteristic (ROC) curve was built to evaluate the performance of dPPG metrics in predicting the Hb "trigger threshold" of transfusion (Hb < 60 g/L and Hb > 100 g/L). Agreement and trending ability between Hb measured by dPPG (HbdPPG) and by blood gas analysis were analyzed by Bland-Altman method and polar plot graph. Error grid analysis was also performed to evaluate clinical significance of HbdPPG measurement. RESULTS: The dPPG signal was successfully detected in all of the enrolled experimental pigs, without the occurrence of a continuous loss of dPPG signal for 2 min during the entire measurement. A total of 376 pairs of dPPG signal and Hbi-STAT were acquired. ACred/DCred and ACinf/DCinf had moderate correlations with Hbi-STAT, and the correlation coefficients were 0.790 and 0.782, respectively. The areas under the ROC curve for ACred/DCred and ACinf/DCinf in predicting Hbi-STAT < 60 g/L were 0.85 and 0.75, in predicting Hbi-STAT > 100 g/L were 0.90 and 0.83, respectively. Bland-Altman analysis and polar plot showed a small bias (1.69 g/L) but a wide limit of agreement (-26.02-29.40 g/L) and a poor trend ability between HbdPPG and Hbi-STAT. Clinical significance analysis showed that 82% of the data lay within the Zone A, 18% within the Zone B, and 0% within the Zone C. CONCLUSION: It is feasible to establish a noninvasive and continuous Hb monitoring by transesophageal dPPG signal. The ACred/DCred extracted from the dPPG signal could provide a sensitive prediction of the Hb threshold for transfusion. The Hb concentration measured by dPPG signal has a moderate correlation with that measured by blood gas analysis. This animal study may provide an experimental basis for the development of bedside HbdPPG monitoring in the future.

Measuring Pericellular Oxygen Tension for In Vitro Cell Culture.

Cell culture, the process of growing cells in conditions that mimic those in the body, is a key technique in biomedical research. Oxygen is not controlled in conventional cell culture, although chambers that control oxygen in the surrounding gas phase are commercially available. In both cases, it is valuable to understand the pericellular oxygen tension (i.e., the oxygen concentration that cells experience) in cultures. Herein we describe a procedure for using commercial optical sensor spots to measure pericellular oxygen for adherent and suspension cultures. Spots are placed on surfaces on which cells are grown, and optical cables are attached to the outside of the cell culture vessels and connected to a computer. Associated software allows for the real-time monitoring of pericellular oxygen during cell culture experiments. This procedure enhances the reproducibility and control of cell culture.

Impact of mechanical power and positive end expiratory pressure on central vs. mixed oxygen and carbon dioxide related variables in a population of female piglets.

INTRODUCTION: The use of the pulmonary artery catheter has decreased overtime; central venous blood gases are generally used in place of mixed venous samples. We want to evaluate the accuracy of oxygen and carbon dioxide related parameters from a central versus a mixed venous sample, and whether this difference is influenced by mechanical ventilation. MATERIALS AND METHODS: We analyzed 78 healthy female piglets ventilated with different mechanical power. RESULTS: There was a significant difference in oxygen-derived parameters between samples taken from the central venous and mixed venous blood (S v ¯ $$ \overline{v} $$ O2 = 74.6%, ScvO2 = 83%, p < 0.0001). Conversely, CO2-related parameters were similar, with strong correlation. Ventilation with higher mechanical power and PEEP increased the difference between oxygen saturations, (Δ[ScvO2-S v ¯ $$ \overline{v} $$ O2 ] = 7.22% vs. 10.0% respectively in the low and high MP groups, p = 0.020); carbon dioxide-related parameters remained unchanged (p = 0.344). CONCLUSIONS: The venous oxygen saturation (central or mixed) may be influenced by the effects of mechanical ventilation. Therefore, central venous data should be interpreted with more caution when using higher mechanical power. On the contrary, carbon dioxide-derived parameters are more stable and similar between the two sampling sites, independently of mechanical power or positive end expiratory pressures.

Reliability of a point of care testing blood gas analyzer for measurement of lactate levels in cerebrospinal fluid.

Analysis of cerebrospinal fluid (CSF), including lactate, is key for diagnosis of acute meningitis. Since blood gas analyzers (BGA) enable rapid and safe blood-lactate measurements, we evaluated the reliability of RAPIDPoint 500 BGA to provide a fast and accurate measure of CSF lactate. In this study, CSF lactate levels were measured by a reference assay and on RAPIDPoint 500 BGA. Comparability was evaluated through difference analysis, using Bland Altman test, and linear regression analysis, using the Passing Bablok test. Agreement rate according to CSF lactate (≥3.5 and <3.5 mmol/L) was calculated using kappa (κ) statistic. Population study included 98 CSF samples. Concerning difference analysis, according to Bland-Altman test, bias was 0.13 mmol/L (CI 95%: -0.26 to 0.52 mmol/L. In regression analysis, according to Passing-Bablok equation a systematic difference between both assays was found. In concordance analysis, the interrate realibility was very high (κ: 0.964). According to our resuls, although a systematic difference was detected when lactate levels were measured on RAPIDPoint 500 BGA, the results from Bland-Altman test and the high agreement rate support that this POCT analyzer could be useful for a early and safe detection of patients with high probability of increased CSF lactate level.