Comparison of different methods for measurement of electrolytes in patients admitted to the intensive care unit

Objectives:

To investigate whether electrolyte levels measured by using blood gas analyzers (ABG) and auto-analyzers (AA) are equivalent and can be used interchangeably.

Methods:

This observational prospective study was conducted in 100 patients admitted to the Intensive Care Unit, Adnan Menderes University School of Medicine, Aydin, Turkey, between March and August 2014. Samples for both AA and ABG analyzers were collected simultaneously from invasive arterial catheters of patients. The electrolyte levels were measured by using 2 methods.

Results:

The mean sodium level measured by ABG was 136.1±6.3 mmol/L and 137.8±5.4 mmol/L for AA (p=0.001). The Pearson’s correlation coefficient was 0.561 (p<0.001). The Bland-Altman 95% limits of agreement were -9.4 to 12.6 mmol/L. The mean potassium levels measured by ABG was 3.4±0.7 mmol/L and AA was 3.8±0.7 mmol/L (p=0.001). The Bland-Altman comparison limits were -0.58 to 1.24 and the associated Pearson’s correlation coefficient was 0.812 (p<0.001).

Conclusion:

The results of the 2 analyzing methods, in terms of sodium, were not equivalent and could not be used interchangeably. However, according to the statistical analyses results, by including, but not blindly trusting these findings, urgent and vital decisions could be made by the potassium levels obtained from the BGA, but a simultaneous follow-up sample had to be sent to the central laboratory for confirmation.Electrolytes are very important for the continuation of the physiological functions of the human body. They play vital roles in: regulation of the cell membrane potential, steady process of neurohormonal pathways, energy transformation and the fluid, and acid-base balance in the body. Signs and symptoms of electrolyte disorders may be nonspecific in an intensive care unit (ICU) patient.1-3 The therapies directed for maintaining vital organ functions affect the electrolyte balance. Consequently, electrolyte disorders are more common in critically ill patients than non-critically ill patients.1 The incidence of electrolyte disorders is nearly 25% in ICU patients.2 In recent studies,4-6 it is shown that in ICU patients, serum sodium and potassium levels are significant predictors of mortality. Therefore, prompt and complete correction of electrolyte disorders in ICU patients is vitally important. Under these circumstances, the importance of obtaining the results of serum electrolyte levels at the earliest is obvious. In routine application, serum electrolytes are measured by the indirect ion-sensing (ISE) method using auto-analyzers (AA) located in the central laboratories of hospitals. In this analyzing method, the processing time is longer because of a delay in the transportation of the samples to the central laboratory on account of several reasons.7 Hence, point-of-care (POC) testing methods, such as, arterial blood gas (ABG) analyzers have been increasingly used in the daily assessments of ICU patients. Blood gas analyzers; use the direct ISE method with short processing time that provides time and rapidity to the physician in the patient’s treatment decisions.7,8 The United States Clinical Laboratory Improvement Amendments (US CLIA) accepts a 0.5 mmol/l difference in the measured potassium levels and a 4 mmol/l difference in the measured sodium levels, in the gold standard measure of the standard calibration solution.9 In some recent studies, the data revealed the difference in the electrolyte levels between the ABG and AA results.10,11 Furthermore, there are also studies that suggest that there is no significant difference between these measuring methods.12,13 Physicians want to trust the veracity of the ABG results of electrolytes such as sodium and potassium because, by this method, the delay in reaching the results is surpassed, and risks arising from this delay may be reduced. However, the results of the above-mentioned studies are confusing and still a diagnostic challenge for physicians. On account of the hesitation by the physicians, we decided to investigate whether the sodium and potassium levels measured by using ABG and AA were equivalent. We conducted a prospective study comparing the electrolyte level results measured in the arterial blood samples by 2 different methods. We tried to notice all limitations of previous similar studies and designed our study according to these points. Thereby, we aimed to improve the accuracy of our study results.     

Ultrasound-guided retrograde popliteal artery catheterization: experience in 174 consecutive patients.

PURPOSE: To assess the safety and efficacy of ultrasound (US) guidance during retrograde popliteal artery catheterization (RPAC) and identify the risk factors for late hemostasis and complications. METHODS: A retrospective review was undertaken of consecutive patients who underwent grayscale US-guided RPAC during the last 8 years. Chart review identified 174 patients (150 men; mean age 61+/-10 years, range 37-84) with 247 iliofemoral lesions, which were treated via US-guided RPAC. Complications were classified as puncture-related versus angioplasty-related and major versus minor. Risk factors for complications and late hemostasis were evaluated with logistic and linear regression analyses, respectively. RESULTS: All 234 US-guided RPACs were technically successful. No arteriovenous fistula (AVF) or dissection/thrombosis of the popliteal artery was observed. The mean time to hemostasis was 6.9+/-2.3 minutes. The presence of femoral stenosis (versus occlusion) and use of large (6 to 7-F) sheaths were significant risk factors for late hemostasis. In 234 procedures, 15 (6.4%) complications developed; 10 (4.3%) were puncture-related (3 major, 7 minor) and 5 (2.1%) were angioplasty-related (3 major, 2 minor). Intra-arterial fibrinolysis was found to be the only significant risk factor for overall and puncture-related complications. CONCLUSIONS: Our results suggest that US-guided RPAC is at least as safe as other RPAC methods described in the literature. In contrast to generally held concerns, hemostasis is easy to obtain, and multiple punctures and the use of large sheaths appear safe. These results should be taken into consideration during the selection of an access site for endovascular treatment of superficial femoral artery and tandem iliofemoral lesions.     

Orientation dependence in fluorescent energy transfer between Cy3 and Cy5 terminally attached to double-stranded nucleic acids

We have found that the efficiency of fluorescence resonance energy transfer between Cy3 and Cy5 terminally attached to the 5′ ends of a DNA duplex is significantly affected by the relative orientation of the two fluorophores. The cyanine fluorophores are predominantly stacked on the ends of the helix in the manner of an additional base pair, and thus their relative orientation depends on the length of the helix. Observed fluorescence resonance energy transfer (FRET) efficiency depends on the length of the helix, as well as its helical periodicity. By changing the helical geometry from B form double-stranded DNA to A form hybrid RNA/DNA, a marked phase shift occurs in the modulation of FRET efficiency with helix length. Both curves are well explained by the standard geometry of B and A form helices. The observed modulation for both polymers is less than that calculated for a fully rigid attachment of the fluorophores. However, a model involving lateral mobility of the fluorophores on the ends of the helix explains the observed experimental data. This has been further modified to take account of a minor fraction of unstacked fluorophore observed by fluorescent lifetime measurements. Our data unequivocally establish that Förster transfer obeys the orientation dependence as expected for a dipole–dipole interaction.     

Amyloid goiter related with Crohn's disease: A rare association: Amyloid goiter secondary to Crohn's disease

INTRODUCTION

Amyloid goiter (AG) is characterized by enlargement of the thyroid gland as a result of extensive amyloid deposition in a bilateral and diffuse manner.

PRESENTATION OF CASE

A 58-year-old male patient was diagnosed of Crohn''s Disease (CD). He was admitted to our clinic with complaint of respiratory distress and rapid growth swelling in the neck. Ultrasound examination revealed huge multinodular goiter on both sides of thyroid gland. We performed bilateral total thyroidectomy. Pathological evaluation revealed AG.

DISCUSSION

Amyloid leads to degeneration in tissues, thereby disrupts the function of the relevant organs. It is important to distinguish AG from other reasons of goiter, particularly thyroid medullary cancer that can cause amyloid deposition in thyroid gland. Secondary amyloidosis frequently involves thyroid gland at microscopic level, but rarely causes goiter. An analysis of current literature revealed that only few cases of AG occurred secondary to CD. Herein we presented a case of AG who has rapidly growing goiter that associated with CD.

CONCLUSION

AG must be kept in mind in case of rapidly growing goiter, especially in patients with chronic inflammatory bowel diseases.     

Neonatal Infection with Neisseria meningitidis: Analysis of a 97-Year Period Plus Case Study

Neisseria meningitidis is one of the major causes of meningitis in children and adolescents, but it is rarely found during the neonatal period. Here, we describe a neonate with meningococcal sepsis who was admitted to the hospital on postnatal day 10, and we discuss the clinical features of neonatal infection with N. meningitidis in relation to the literature (analysis of a 97-year period).