Determination of the Dissociation Constant (Ka) of Plasma and Whole Blood in Septic Patients

NCT ID: NCT03966664

Last Updated: 2019-06-04

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

UNKNOWN

Total Enrollment

90 participants

Study Classification

OBSERVATIONAL

Study Start Date

2019-06-03

Study Completion Date

2021-06-30

Brief Summary

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Alterations of acid-base equilibrium are very common in critically ill patients and understanding their pathophysiology can be important to improve clinical treatment.

Detailed Description

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Acid-base equilibrium has been object of study for more than 100 years in medicine because of its relevance in patients' management and in determining their prognosis, especially in the ICU.

A concept closely related to acid-base equilibrium is that of "buffer", term used to define any substance able to limit the changes in pH caused by the addition or loss of alkali or acid.

Depending on its physiochemical features, every buffer has one or more pH (negative logarithm of hydrogen ion concentration) values where its ability to keep pH stable is maximal. These values are defined as Ka or semi equivalence points, i.e. the pH values where the buffer dissolved in solution is half in its associated form (AH) and half in its dissociated form (A-).

Several studies tried to determine the normal values of both concentration and Ka of ATOT. However, they did not lead to univocal results. Moreover, many of these values come from studies of veterinary medicine or are the result of theoretical estimates on human plasma.

Staempfli and Constable performed a single experimental study on human plasma in 2003. These authors, however, analyzed only isolated plasma, neglecting whole blood, and computed ATOT and Ka values of healthy volunteers, while Ka and ATOT values for critically ill patients with sepsis are still unknown.

Primary aim of the present study is to quantify the acidic dissociation constant (Ka) of isolated plasma of critically ill patients with sepsis, and compare these data with normal values, i.e. obtained from healthy controls. The investigators hypothesize that plasma of critically ill septic patients has a lower Ka and that, consequently, it undergoes higher pH variations for a given perturbation of the system (variation in carbon dioxide).

Secondary aim is to quantify the Ka of whole blood of critically ill patients with sepsis and compare these data with normal values, i.e. obtained from healthy controls. The investigators hypothesize that blood of critically ill septic patients has a lower Ka and that, consequently, it undergoes higher pH variations for a given perturbation of the system (variation in carbon dioxide).

Other aims of the study are:

* quantify the Ka of plasma and whole blood of non-septic patients admitted to the ICU and compare these results with the values of septic patients and healthy volunteers.
* define the normal concentration of weak non-carbonic acids (ATOT) in plasma of septic patients and compare it with data obtained in healthy volunteers and non-septic patients.

Finally, possible structural alteration of plasma proteins will be evaluated:

* Identification of differentially modified proteoforms of serum albumin and major plasma proteins by two-dimensional electrophoresis;
* High Performance Liquid Chromatography (HPLC) to identify different Redox-forms of albumin
* Spectrophotometric evaluation of modifications of ligand binding properties of serum albumin.

Conditions

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Sepsis Septic Shock Critical Illness Respiratory Acidosis Respiratory Alkalosis Acid-Base Imbalance

Study Design

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Observational Model Type

CASE_CONTROL

Study Time Perspective

PROSPECTIVE

Study Groups

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Septic patients

Critically ill patients of both sexes admitted to the general ICU of the participating centers with the diagnosis of sepsis will be included.

In vitro determination the dissociation constant (Ka) and total amount of non-volatile buffers (Atot) in isolated plasma.

Intervention Type DIAGNOSTIC_TEST

Collection of a venous blood sample, centrifugation in order to harvest isolated plasma and performance of in-vitro tonometry in order to assess Ka and Atot.

In vitro determination the dissociation constant (Ka) and total amount of non-volatile buffers (Atot) in whole blood

Intervention Type DIAGNOSTIC_TEST

Collection of a venous blood sample and performance of in-vitro tonometry in order to assess Ka and Atot.

Biomolecular analysis of plasma proteins.

Intervention Type DIAGNOSTIC_TEST

Bidimensional electrophoresis, determination of oxidized albumin fraction, characterization of altered ligand binding properties of plasma albumin.

Healthy controls

Age and sex matched healthy volunteers.

In vitro determination the dissociation constant (Ka) and total amount of non-volatile buffers (Atot) in isolated plasma.

Intervention Type DIAGNOSTIC_TEST

Collection of a venous blood sample, centrifugation in order to harvest isolated plasma and performance of in-vitro tonometry in order to assess Ka and Atot.

In vitro determination the dissociation constant (Ka) and total amount of non-volatile buffers (Atot) in whole blood

Intervention Type DIAGNOSTIC_TEST

Collection of a venous blood sample and performance of in-vitro tonometry in order to assess Ka and Atot.

Biomolecular analysis of plasma proteins.

Intervention Type DIAGNOSTIC_TEST

Bidimensional electrophoresis, determination of oxidized albumin fraction, characterization of altered ligand binding properties of plasma albumin.

Non septic patients

Non-septic patients admitted to the general ICU of the participating centers after elective non-cardiac surgery.

In vitro determination the dissociation constant (Ka) and total amount of non-volatile buffers (Atot) in isolated plasma.

Intervention Type DIAGNOSTIC_TEST

Collection of a venous blood sample, centrifugation in order to harvest isolated plasma and performance of in-vitro tonometry in order to assess Ka and Atot.

In vitro determination the dissociation constant (Ka) and total amount of non-volatile buffers (Atot) in whole blood

Intervention Type DIAGNOSTIC_TEST

Collection of a venous blood sample and performance of in-vitro tonometry in order to assess Ka and Atot.

Biomolecular analysis of plasma proteins.

Intervention Type DIAGNOSTIC_TEST

Bidimensional electrophoresis, determination of oxidized albumin fraction, characterization of altered ligand binding properties of plasma albumin.

Interventions

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In vitro determination the dissociation constant (Ka) and total amount of non-volatile buffers (Atot) in isolated plasma.

Collection of a venous blood sample, centrifugation in order to harvest isolated plasma and performance of in-vitro tonometry in order to assess Ka and Atot.

Intervention Type DIAGNOSTIC_TEST

In vitro determination the dissociation constant (Ka) and total amount of non-volatile buffers (Atot) in whole blood

Collection of a venous blood sample and performance of in-vitro tonometry in order to assess Ka and Atot.

Intervention Type DIAGNOSTIC_TEST

Biomolecular analysis of plasma proteins.

Bidimensional electrophoresis, determination of oxidized albumin fraction, characterization of altered ligand binding properties of plasma albumin.

Intervention Type DIAGNOSTIC_TEST

Eligibility Criteria

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Inclusion Criteria

* Diagnosis of Sepsis
* Age \> 18 years
* Informed or deferred informed consent


* informed consent
* Age \> 18 years


* Informed consent
* Age \>18 years
* Planned ICU admission after elective surgery

Exclusion Criteria

* Pregnancy
* Bilirubin \> 4 mg/dL
* Minor or major thalassemia
* Transfusion of more than 4 Units of packed red blood cells and/or 1 L of plasma during the 24 hours prior to enrollment

Group 2: Healthy volunteers


• Pregnancy

Group 3: Non-septic patients


* Diagnosis of sepsis
* Pregnancy
* Bilirubin \>4 mg/dL
* Liver cirrhosis
* Onco-hematological diseases
* Minor or major thalassemia
* Transfusion of more than 4 Units of packed red blood cells and/or 1 L of plasma during the 24 hours prior to enrollment
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Charles University, Czech Republic

OTHER

Sponsor Role collaborator

Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Thomas Langer, MD

Role: PRINCIPAL_INVESTIGATOR

Fondazione IRCCS Ca' Granda Hospital, Milano, Italy

Antonio M Pesenti, MD

Role: STUDY_CHAIR

Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico

Frantisek Duska, MD

Role: PRINCIPAL_INVESTIGATOR

Third faculty of Medicine, Charles University, Prague

Giacomo Grasselli, MD

Role: STUDY_CHAIR

Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico

Paul Elbers, MD

Role: STUDY_CHAIR

Amsterdam UMC, Department of Intensive Care Medicine

Locations

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Third faculty of Medicine, Charles University of Prague

Prague, , Czechia

Site Status RECRUITING

Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico

Milan, , Italy

Site Status RECRUITING

Countries

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Czechia Italy

Central Contacts

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Thomas Langer, MD

Role: CONTACT

0255033232

Facility Contacts

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Frantisek Duska, MD

Role: primary

Thomas Langer, MD

Role: primary

025503 ext. 3232

References

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Henderson LJ. THE REGULATION OF NEUTRALITY IN THE ANIMAL BODY. Science. 1913 Mar 14;37(950):389-95. doi: 10.1126/science.37.950.389. No abstract available.

Reference Type BACKGROUND
PMID: 17795147 (View on PubMed)

Lee SW, Hong YS, Park DW, Choi SH, Moon SW, Park JS, Kim JY, Baek KJ. Lactic acidosis not hyperlactatemia as a predictor of in hospital mortality in septic emergency patients. Emerg Med J. 2008 Oct;25(10):659-65. doi: 10.1136/emj.2007.055558.

Reference Type BACKGROUND
PMID: 18843064 (View on PubMed)

Fencl V, Leith DE. Stewart's quantitative acid-base chemistry: applications in biology and medicine. Respir Physiol. 1993 Jan;91(1):1-16. doi: 10.1016/0034-5687(93)90085-o.

Reference Type BACKGROUND
PMID: 8441866 (View on PubMed)

LEEUWEN AM. NET CATION EQUIVALENCY ('BASE BINDING POWER') OF THE PLASMA PROTEINS. Acta Med Scand. 1964;176:SUPPL 422: 1+. No abstract available.

Reference Type BACKGROUND
PMID: 14204741 (View on PubMed)

Figge J, Mydosh T, Fencl V. Serum proteins and acid-base equilibria: a follow-up. J Lab Clin Med. 1992 Nov;120(5):713-9.

Reference Type BACKGROUND
PMID: 1431499 (View on PubMed)

Stampfli HR, Misiaszek S, Lumsden JH, Carlson GP, Heigenhauser GJ. Weak acid-concentration Atot and dissociation constant Ka of plasma proteins in racehorses. Equine Vet J Suppl. 1999 Jul;(30):438-42.

Reference Type BACKGROUND
PMID: 10659296 (View on PubMed)

Staempfli HR, Constable PD. Experimental determination of net protein charge and A(tot) and K(a) of nonvolatile buffers in human plasma. J Appl Physiol (1985). 2003 Aug;95(2):620-30. doi: 10.1152/japplphysiol.00100.2003. Epub 2003 Mar 28.

Reference Type BACKGROUND
PMID: 12665532 (View on PubMed)

Langer T, Scotti E, Carlesso E, Protti A, Zani L, Chierichetti M, Caironi P, Gattinoni L. Electrolyte shifts across the artificial lung in patients on extracorporeal membrane oxygenation: interdependence between partial pressure of carbon dioxide and strong ion difference. J Crit Care. 2015 Feb;30(1):2-6. doi: 10.1016/j.jcrc.2014.09.013. Epub 2014 Sep 22.

Reference Type BACKGROUND
PMID: 25307980 (View on PubMed)

Other Identifiers

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ENTERPRISE

Identifier Type: -

Identifier Source: org_study_id

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