Venous Blood Gas Samples Research Articles

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.

Can end-tidal CO2 measurement replace arterial partial CO2 in emergency department respiratory distress management?

ObjectiveTo assess the feasibility of using end-tidal carbon dioxide (EtCO2) as a non-invasive substitute for partial pressure of arterial carbon dioxide (PaCO2) in emergency department (ED) triage and follow-up, and to explore the potential of partial pressure of venous carbon dioxide (PvCO2) as an alternative to PaCO2. DesignProspective cross-sectional study. SettingTertiary university hospital. Patients or participants97 patients presenting with acute respiratory distress to the ED. InterventionsEtCO2, arterial blood gases, and venous blood gases measured at admission (0 min), 60 min, and 120 min. Main variables of interestCO2 levels. ResultsAmong 97 patients (mean age: 70.93 ± 9.6 years; 60.8% male), EtCO2 > 45 mmHg at admission showed strong positive correlations with PaCO2 and PvCO2 (r = 0.844, r = 0.803; p < 0.001, respectively). Significant positive correlation was observed between 60-min EtCO2 and PaCO2 (r = 0.729; p < 0.001). Strong correlation between PaCO2 and PvCO2 at 120 min when EtCO2 > 45 mmHg (r = 0.870; p < 0.001). EtCO2 was higher in hospitalized patients compared to discharged ones. ConclusionsEtCO2 appears promising as a substitute for PaCO2 in ED patients with acute respiratory distress within the initial two hours of treatment. Venous blood gas sampling offers a less invasive alternative to arterial sampling, facilitating simultaneous blood tests.

Effect of Deep Hypothermia (18°C) on Dioxygen Metabolism During Pulmonary Thromboendarterectomy Surgery

Objectives: The aim of this physiological pilot study was to investigate the effect of deep hypothermia on oxygen extraction (OE) and consumption (VO2) in normothermic conditions (36-37°C) then at different stages of cooling: 30°C, 25°C and 18°C. Design: For three months, we conduct a prospective study on patients that underwent pulmonary thromboendarterectomy. Settings: This is a single center study done in a university teaching hospital. ParticipantsPatients that underwent pulmonary thromboendarterectomy during the inclusion period. InterventionsHemodynamic and biological data were recorded from arterial and venous blood gas samples withdrawn first at normothermia, then at 30°C, 25°C and 18°C.. Measurements and Main Results24 patients were included in the final analysis. Indexed VO2 decreased from 65.9 ml to 25.1 ml of O2/min/m2 between 36°C and 18°C (p<0.001). The OE decreased from 18% to 9% between 36°C and 18°C (p<0.001). At normal temperature and at 18°C, the median venoarterial difference of O2 bound to hemoglobin was 2.22 [1.68-2.58] and 0.03 [0.01-0.07] ml of O2/100 ml of blood, respectively (p<0.001). Whereas the median venoarterial difference of dissolved O2 was 0.78 [0.66-0.92] and 1.09 [1.03-1.32] ml of O2/100 ml of blood, respectively (p=0.0013). Conclusion: There is a VO2 and OE decrease of more than half of their baseline value at 18°C. Seeing that the metabolic needs are essentially supplied from dissolved O2 during cooling from 30°C to 18°C, we suggest that PaO2 should be increased during the period of cooling and/or of deep hypothermia to prevent hypoxia.

Can end-tidal CO2 measurement replace arterial partial CO2 in emergency department respiratory distress management?

ObjectiveTo assess the feasibility of using end-tidal carbon dioxide (EtCO2) as a non-invasive substitute for partial pressure of arterial carbon dioxide (PaCO2) in emergency department (ED) triage and follow-up, and to explore the potential of partial pressure of venous carbon dioxide (PvCO2) as an alternative to PaCO2. DesignProspective cross-sectional study. SettingTertiary university hospital. Patients or participants97 patients presenting with acute respiratory distress to the ED. InterventionsEtCO2, arterial blood gases, and venous blood gases measured at admission (0 min), 60 min, and 120 min. Main variables of interestCO2 levels. ResultsAmong 97 patients (mean age: 70.93 ± 9.6 years; 60.8% male), EtCO2 > 45 mmHg at admission showed strong positive correlations with PaCO2 and PvCO2 (r = 0.844, r = 0.803; p < 0.001, respectively). Significant positive correlation was observed between 60-min EtCO2 and PaCO2 (r = 0.729; p < 0.001). Strong correlation between PaCO2 and PvCO2 at 120 min when EtCO2 > 45 mmHg (r = 0.870; p < 0.001). EtCO2 was higher in hospitalized patients compared to discharged ones. ConclusionsEtCO2 appears promising as a substitute for PaCO2 in ED patients with acute respiratory distress within the initial two hours of treatment. Venous blood gas sampling offers a less invasive alternative to arterial sampling, facilitating simultaneous blood tests.

Evaluating the efficacy of a standardized 4 mL/kg fluid bolus technique in critically ill patients with elevated PvaCO2: secondary analysis of two prospective studies.

Limiting the fluid bolus (FB) volume may attenuate side effects, including hemodilution and increased filling pressures, but it may also reduce hemodynamic responsiveness. The minimum volume to create hemodynamic effects is considered to be 4 mL/kg. In critically ill patients, the hemodynamic effects of FB with this volume have not been adequately investigated and compared to higher quantities. We hypothesized that a standardized FB approach using 4 mL/kg has comparable hemodynamic and metabolic effects to the common practice of physician-determined FB in critically ill patients. We conducted post hoc analysis of two trials in non-selected critically ill patients with central venous-to-arterial CO2 tension (PvaCO2) >6 mmHg and no acute bleeding. All patients received crystalloids either at a physician-determined volume and rate or at 4 mL/kg pump-administered at 1.2 L/h. Cardiac index (CI) was calculated with transthoracic echocardiogram, and arterial and venous blood gas samples were assessed before and after FB. Endpoints were changes in CI and oxygen delivery (DO2) >15%. A total of 47 patients were eligible for the study, 15 of whom received physician-determined FB and 32 of whom received standardized FB. Patients in the physician-determined FB group received 16 (12-19) mL/kg at a fluid rate of 1.5 (1.5-1.9) L/h, compared to 4.1 (3.7-4.4) mL/kg at a fluid rate of 1.2 (1.2-1.2) L/h (p < 0.01) in the standardized FB group. The difference in CI elevations between the two groups was not statistically significant (8.8% [-0.1-19.9%] vs. 8.4% [0.3-23.2%], p = 0.76). Compared to physician-determined FB, the standardized FB technique had similar probabilities of increasing CI or DO2 by >15% (odds ratios: 1.3 [95% CI: 0.37-5.18], p = 0.66 and 1.83 [95% CI: 0.49-7.85], p = 0.38). A standardized FB protocol (4 mL/kg at 1.2 L/h) effectively reduced the volume of fluid administered to critically ill patients without compromising hemodynamic or metabolic effects.

Comparison of Liquid Sodium Heparin Syringe and Preheparinised Syringe for Sample Rejection in Arterial Blood Gas Analysis: A Cross-sectional Study

Introduction: In hospital settings, Arterial Blood Gas (ABG) analysis is a routine investigation. Many errors can arise in the process, with 70% of errors in ABG analysis occurring during the preanalytical phase. Liquid heparin is commonly used as an anticoagulant in sample collection devices for Blood Gas (BG) analysis; however, inadequate heparin concentration and improper mixing of blood samples after collection often lead to incorrect results. This can be prevented by using syringes preloaded with lyophilised heparin. Aim: To monitor the prevalence of sample rejection collected by the device using liquid sodium heparin and calcium-balanced dried lithium heparin. Materials and Methods: This cross-sectional study was conducted at the ABG laboratory, Department of Biochemistry, Amrita Institute of Medical Sciences and Research Centre, Amrita Viswavidyapeetham University, Kochi, Kerala, India over a 4-month period from December 2022 to March 2023. ABG samples collected using either of the techniques were included, while venous BG samples were excluded. The sample size was 10,957 for each of the two groups- Group A and Group B. Group A included samples collected using liquid sodium heparin, and group B included spray-dried, calcium-balanced lithium heparin from different departments. The incidence of blood clots, air bubbles, and inadequate volume was studied. For all categorical variables, the results were expressed as the frequency and percentage of errors. An unpaired t-test (two-tailed) was used for data analysis. Results: In comparison with liquid sodium heparin collection, errors in the quality of the specimen such as blood clots (1.7% to 1.1%), air bubbles (0.04% to 0%), and inadequate volume (0.2% to 0.03%) were significantly reduced (p-value=0.002) with spray-dried, calcium-balanced lithium heparin (BD Preset™ Safety BG Syringe). Conclusion: The present study found that using calcium- balanced lithium heparin syringes over manually flushed liquid sodium heparin syringes reduces the risk of clots, thus preventing equipment malfunction and maintenance costs. With the introduction of preset syringes, the chance of air bubbles and insufficient volume can also be overcomed.

Agreement of pCO2 in venous to arterial blood gas conversion models in undifferentiated emergency patients

BackgroundVenous blood gas sampling has replaced arterial sampling in many critically ill patients, though interpretation of venous pCO2 still remains a challenge. Lemoël et al., Farkas and Zeserson et al. have proposed models to estimate arterial pCO2 based on venous pCO2. Our objective was to externally validate these models with a new dataset. This was a prospective cross-sectional study of consecutive adult patients with a clinical indication for blood gas analysis in an academic emergency department in Sweden. Agreement of pairs was reported as mean difference with limits of agreement (LoA). Vital signs and lead times were recorded.ResultsTwo hundred and fifty blood gas pairs were collected consecutively between October 2021 and April 2022, 243 valid pairs were used in the final analysis [mean age 72.8 years (SD 17.8), 47% females]. Respiratory distress was the most common clinical indication (84% of all cases). The model of Farkas showed the best metrics with a mean difference between estimated and arterial pCO2 of − 0.11 mmHg (95% LoA − 6.86, + 6.63). For Lemoël the difference was 2.57 mmHg (95% LoA − 5.65, + 10.8), Zeserson 2.55 mmHg (95% LoA − 7.43, + 12.53). All three models showed a decrease in precision in patients with ongoing supplemental oxygen therapy.ConclusionArterial pCO2 may be accurately estimated in most patients based on venous blood gas samples. Additional consideration is required in patients with hypo- or hypercapnia or oxygen therapy. Thus, conversion of venous pCO2 may be considered as an alternative to arterial blood gas sampling with the model of Farkas being the most accurate.

Exploring the Feasibility of Calculating Expected pCO2 From Venous Blood Gas Samples Alone in Intensive Care Patients.

Introduction This study highlights the significance of assessing acid-base balance and gas exchange in intensive care patients. The research investigates the applicability of using the "expected (pCO2 = HCO3 + 15)" formula, derived from venous blood gas samples, as an alternative to Winter's formula and practical formula. The study emphasizes the importance of identifying the primary acid-base abnormality accurately and efficiently for appropriate clinical intervention in critically ill patients. Methods This study included 400 adult patients admitted to the Anesthesia Clinic in the Third Stage Anesthesia and Reanimation Intensive Care Unit at Hitit University Erol Olçok Training and Research Hospital between April 2020 and July 2023. Blood gas samples were collected simultaneously from both arterial lines and venous catheters. Patients under 18 years, pregnant women, hemodialysis patients, and those with missing data were excluded. The study aimed to calculate the expected partial pressure of carbon dioxide (pCO2) values using Winter's formula and simple formulafor both arterial and venous blood gas samples and assess potential correlations between them. Results The results showed a narrow range for arterial pH values (7.12-7.72), a wider distribution for pCO2 values (17.90-81.30 mmHg), and a moderate dispersion for HCO3values (12.80-44.33 mmol/L). Both Winter's and simple formulas were applied to estimate the expected pCO2 values, showing strong positive correlations between arterial and venous pH, pCO2, and HCO3 values. The scatterplot illustrated a very high level of association (Pearson's correlation coefficient, r = 1) between the expected pCO2 values derived from both formulas using arterial and venous blood gas samples. Conclusion The clinical study demonstrates that estimating expected pCO2 values in mixed acid-base disorders can be achieved using a simple and convenient formulation, eliminating the need for arterial blood gas sampling and its associated complications.

Prophylactic Fixed-Rate Phenylephrine Versus Norepinephrine Infusion in the Prevention of Post-spinal Anesthesia Hypotension During Cesarean Delivery.

Background Maternal hypotension following spinal anesthesia can be actively countered by the use of vasopressors. Prophylactic infusion of vasopressors with a rescue bolus dosing was observed to be more effective for hemodynamic stability when compared to administering a bolus dose alone. Although phenylephrine is the recommended drug to treat spinal hypotension, many recent studies have focussed on the role of norepinephrine infusions during cesarean section. In this study, we compared prophylactic fixed-rate intravenous infusions of phenylephrine and norepinephrine during cesarean delivery under spinal anesthesia and the requirement of intraoperative provider-administered rescue bolus of phenylephrine needed to overcome post-spinal anesthesia hypotension. Methodology A total of 208 patients undergoing elective cesarean section under spinal anesthesia were randomly assigned to two groups (group P and group N). Group N included 104 patients who received norepinephrine infusion at a rate of 2.5 μg/minute (0.04 μg/kg/minute), and group P included 104 patients who received phenylephrine infusion at a rate of 50 μg/minute (0.8 μg/kg/minute)to treat spinal hypotension. The primary outcome of our study was to compare the reduction in the number and total dose of intraoperative provider-administered rescue bolus of phenylephrine needed to maintain systolic blood pressure. The secondary outcome of our study was to compare the neonatal outcome using umbilical venous blood gas sampling and Apgar score at one and five minutes. Results The total number of phenylephrine rescue bolus required to treat hypotension was significantly lower in group N (p = 0.0005) compared to group P. The neonatal outcome was similar between the two groups. Conclusions Prophylactic norepinephrine infusion when compared to prophylactic phenylephrine infusion is associated with a lesser requirement of rescue phenylephrine boluses.

Comparison of mathematically arterialised venous blood gas sampling with arterial, capillary, and venous sampling in adult patients with hypercapnic respiratory failure: a single-centre longitudinal cohort study

BackgroundAccurate arterial blood gas (ABG) analysis is essential in the management of patients with hypercapnic respiratory failure, but repeated sampling requires technical expertise and is painful. Missed sampling is common...

Evaluation of cardiovascular effects of intramuscular medetomidine and a medetomidine–vatinoxan combination in Beagle dogs: A randomized blinded crossover laboratory study

ObjectiveTo compare the cardiovascular effects of a combination of medetomidine and vatinoxan (MVX) versus medetomidine (MED) alone administered intramuscularly (IM) and to determine whether heart rate (HR) can be used as a surrogate for cardiac output (CO) after the use of medetomidine with or without vatinoxan. Study designA randomized, blinded, experimental, crossover study. AnimalsA group of eight healthy Beagle dogs aged 4.6 (2.3–9.4) years and weighing 12.9 (9–14.7) kg, median (range). MethodsEach dog was injected with 1 mg m–2 medetomidine with or without 20 mg m–2 vatinoxan IM with a washout period of 7 days. Cardiovascular data and arterial and mixed venous blood gas samples were collected at baseline, 5, 10, 15, 20, 35, 45, 60, 90 and 120 minutes after treatment administration. CO was measured at all time points via thermodilution. Differences between treatments, period and sequence were evaluated with repeated measures analysis of covariance and the relationship between HR and CO was assessed with a repeated measures analysis of variance; p values < 0.05 were deemed significant. ResultsThe CO was 47–96% lower after MED than after MVX (p < 0.0001). Increases in systemic, pulmonary arterial and right atrial pressures and oxygen extraction ratio were significantly higher after MED than after MVX (all p < 0.0001). HR was significantly lower after MED and the linear relationship to CO was significant (p < 0.0001). Conclusions and clinical relevanceOverall, MED affected the cardiovascular system more negatively than MVX, and the difference in cardiovascular function between the treatments can be considered clinically relevant. HR was linearly related to CO, and decreases in HR reflected cardiac performance for dogs sedated with medetomidine with or without vatinoxan.

Evaluation of respiratory function in healthcare workers wearing face masks during the COVID-19 pandemic

BackgroundThe COVID pandemic, which has caused high mortality rates worldwide, has mainly affected the working environment of healthcare workers. Metabolic and respiratory changes occur in healthcare workers working with surgical masks. ObjectiveOur aim is to identify the metabolic and respiratory problems faced by healthcare personnel working with surgical masks and to produce solutions to minimize them. MethodsThe study was conducted among emergency service workers who used surgical masks for at least 8 h in the emergency room between June 2020 and July 2020. Venous blood gas samples were taken from the health personnel participating in the study and their vital signs were checked. ResultA total of 60 healthcare professionals with a mean age of 28.20 ± 6.30 years were included in the study. The distribution of men and women in the study was balanced with 30 (50.0%) men and 30 (50.0%) women. When the first and last vital signs (blood pressure, pulse, saturation) of the health workers participating in the study were examined, no statistically significant differences were found (p > 0.05). While there was no statistically significant difference in the Na, Chlorine, Ca values of metabolic indicators (p > 0.05), the first measurements of K (0.017) and Lactate (0.037) values were found to be higher than the last measurements (p > 0.05). The first measurements of the respiratory parameters pH (0.002), pCO2 (0.028), sO2 (0.045) and pO2 (0.048) were lower than the last measurements (p > 0.05). The first measurement value of pCO2 (0.028) was found to be higher than the last (p > 0.05). ConclusionsRegular and long-term use of surgical masks does not harm the body metabolically and respiratorily.

Can expected pCO2 be calculated by pCO2=HCO3+15 formula in central venous blood gas samples?

In mixed acid-base disorders, it is essential to identify the dominant disorder, either metabolic or respiratory. The calculation of expected partial carbondioxide (pCO2) value obtained from arterial blood gas sample can give a clue to the physician about the main disorder. There are several formulas to calculate the expected pCO2 which are not practical to use and require an arterial blood gas sample. The aim of this study is to investigate whether expected pCO2 could be calculated with a simple formula by adding 15 to the bicarbonate (HCO3) value obtained from a central venous blood gas sample. 50 (42.7%) female and 67 (57.3%) male patients aged 18 years and older, hospitalized in the Intensive Care Unit (ICU) between January 2022 and June 2022, whose arterial and central venous blood gas samples were drawn at the same time, were included in this study. Expected pCO2 values were calculated with both Winter's (pCO2 = 1.5 × HCO3 + 8) and simple (pCO2 = HCO3 + 15) formulas from the data obtained from arterial and jugular central venous blood gas samples. A statistically significant strong positive correlation was identified between arterial and venous expected pCO2 values, which were calculated by using both Winter's and simple formulas [Pearson's correlation coefficient (r) = 1, p<0.001]. In ICU patients, (pCO2 = HCO3 + 15) formula can be used to calculate expected pCO2 in central venous blood gas samples to identify the primary disorder as metabolic or respiratory in mixed acid-base disorders.

A Rare case of Miller Fisher Syndrome with Ophthalmoplegia with Bulbar Palsy with Bifacial Weakness with Progressive Quadriparesi

A 20 years old female came to ED with c/o giddiness since 4 days, headache since 3 days with diplopia with slurring of speech, lower limb weakness, difficulty in swallowing, and dropping of left eyelid since 1 day. Patient had no any pre-existing comorbidity and not on any regular medication. Last menstrual period was on 5 days back. On examination Patient was vitally and haemodynamically stable. Diplopia on right sided distant vision present. Venous blood gas samples showed Hyponatremia. On CNS examination the Glasgow coma scale was 15/15 with power in upper and lower limb 5/5 bilaterally. There was no neck stiffness. Gag reflex present. Patient was taken immediately on symptomatic supportive treatment and admitted in Intensive care unit. Patient was planned for contrast enhanced MRI brain, lumbar puncture for CSF study, chest x-ray, ultrasound whole abdomen. Blood samples for complete haemogram and other relevant blood investigations with serum electrolytes sent for further study.

Is Continuous Noninvasive Hemoglobin Monitoring Estimates Timing for Detection of Anemia During Operation better than Clinicians

Blood loss is a common surgical complication, but patient complications and healthcare costscan be exacerbated by needless blood transfusions. Non-invasive and continuous monitoring ofhemoglobin concentrations is possible with the Radical-7 Pulse CO- Oximeter. These determinedvalues are identical to those obtained by blood sampling for hemoglobin concentrations, andthe technique enables continuous monitoring over time of changes in Hemoglobin levels. Aims ofStudy: to investigate whether noninvasive, continuous, and real-time monitoring of Hemoglobincould estimate the timing for further Hemoglobin measurements more accurately than clinicians’discretion during surgery. Patients and Methods: 54 Patients eligible for the study wereunderwent different surgeries with planned invasive venous blood gas sampling for bloodHemoglobin for hemoglobin measurement while Radical-7 Pulse CO-Oximeter continuouslyreading Hemoglobin noninvasively during each surgery. Blood samples were obtained 5 minafter induction of anesthesia (other samples was taken multiple time during operations accordingto time of operation). The Conventional venous blood gas measurements were compared with radical7 co-oximeter obtained at the time of the blood sampling. Results: In our study There was nostatistically significant differences (p&gt;0.05) in mean hemoglobin level, whether measured by SpHbor by conventional laboratory. in addition, Bland–Altman plot was utilized and show no markeddifference between invasive and noninvasive method. All these factors signify a good compatibilitybetween the two methods. Conclusions: The radical 7 satisfactorily follows hemoglobin shifts andmore reliably predicts the required timing for early Hemoglobin management decisions throughoutsurgery.

Accuracy of Potassium Measurement Using Blood Gas Analyzer.

Introduction: Newer blood gas analyzers can measure both blood gases and electrolytes in both arterial and venous blood samples. They are small, compact, and mobile point of care test (POCT) devices. They can produce results in as short as five minutes. We aimed at assessing the accuracy of potassium (K) level measured by gas analyzer (index test) by comparing that to the regular laboratory machine (reference standard) in our hospital. Our goal is to use POCT result of potassium so we may start insulin infusion within five to 10 minutes of arrival of diabetic ketoacidosis (DKA) patients to the emergency room (ER). It takes an average of 30 minutes to get the result using the reference standard machine. Potassium level is needed urgently in cases of DKA before initiating insulin infusion. That is true also during cardiopulmonary resuscitation (CPR) and while replacing K in severe hypokalemia and during the management of hyperkalemia.Methods: We looked into the potassium results from 265 patients who had venous blood gas (VBG) or arterial blood gas (ABG) samples and compared that to results of potassium in venous blood samples of these same patients done simultaneously or within two hours. All patients who had blood gas and venous blood drawn simultaneously or within two hours were eligible irrespective of gender, age, diagnosis, and location in the hospital. Data were collected between January 2019 and June 2019. We excluded all cases that were receiving IV fluids, diuretics, or potassium supplements. Samples examined were from all different areas of the hospital including emergency room (ER), intensive care unit (ICU), and general floors. All ages and all diagnoses were included.Results: We used the Bland-Altman method to analyze our data. More than 95% of the data fell within ± 2 standard deviations (S) of the mean difference strongly suggestive of agreement between the index test and the standard reference of the laboratory methods. The bias was 0.19. Lin’s concordance correlation coefficient was 0.6584.Conclusion: Findings of this study support the use of POCT blood gas analyzer for measuring potassium when the results are needed urgently. When measuring potassium, blood gas analyzers are as accurate as automated analyzers. They produce results in five minutes or so and can be relied upon when potassium level is needed urgently. They are cost-effective and may be available at the bedside.

Reverse pseudohyperkalemia in a newly diagnosed pediatric patient with acute T-cell leukemia and hyperleukocytosis: a case report and literature review

BackgroundHyperkalemia is a serious medical condition that requires immediate intervention. However, pseudohyperkalemia and reverse pseudohyperkalemia are misleading clinical manifestations that can result in incorrect diagnosis and consequent harmful intervention.Case presentationAn 11-year-old girl manifested an incidental finding of hyperleukocytosis (WBC > 400 × 109/L), with 90% blast cells during routine pre-operative investigations for adenotonsillectomy. Initial investigations demonstrated elevated serum potassium levels (7.5 mmol/L), despite concomitantly normal levels in venous blood gas samples (3.9–4.4 mmol/L) and being clinically stable with normal 12-lead ECG. Surprisingly, plasma potassium level was exacerbated, in comparison to the serum level by > 1 mmol/L. This finding is consistent with reverse pseudohyperkalemia that is associated with hyperleukocytosis in acute leukemia that does not require any active intervention.ConclusionThis case report emphasizes the significance of interpreting potassium levels accurately, preferably utilizing whole-blood potassium level over serum and plasma level in newly diagnosed leukemia cases with hyperleukocytosis. Additionally, having a high index for the possibility of reverse pseudohyperkalemia, secondary to leakage from fragile leukocytes, avoids unnecessary treatment that might cause harm to the patient.

Trending peripheral venous PCO2 in patients with respiratory failure using mathematically arterialised venous blood gas samples

BackgroundTrending venous blood gases (VBGs) has been suggested as an alternative to arterial blood gases (ABGs) in patients with respiratory failure, but there are limits to its utility. The aim...

Utility of venous blood gases for the assessment of traumatic shock: a prospective observational study

BackgroundABG samples are often obtained in trauma patients to assess shock severity. Venous blood gas (VBG) sampling, which is less invasive, has been widely used to assess other forms of...

False, Reversed but Not True: A Curious Case of Hyperkalemia

Falsely elevated potassium levels are common in routine laboratory tests and should be differentiated from true hyperkalemia. If the patient is inappropriately treated for hyperkalemia, the resulting hypokalemia can lead to life-threatening cardiac arrhythmias. We present the case of a 67-year-old woman with a past medical history of stable chronic lymphocytic leukemia, who presented for chest pain and had an elevated potassium level of 5.8 mEq/L, which, upon repeat laboratory testing, was then 6.7 mEq/L. She was initially treated for hyperkalemia. Laboratory test results showed creatine kinase levels at 43 U/L, lactate dehydrogenase levels at 177 U/L, phosphorus levels at 4.5 mg/dL, and uric acid levels at 6.4 mg/dL, indicating no evidence of tumor lysis syndrome. The patient was later diagnosed with reverse pseudohyperkalemia, indicated by falsely elevated plasma potassium levels in the presence of serum potassium levels within normal limits and venous blood gas samples.