Intraoperative Cell Salvage and Postoperative Acidosis

The Contribution of Intraoperative Mechanical Red Cell Salvage to Acidosis in the Immediate Postoperative Period After Cardiac Surgery

Metabolic acidosis is a common complication that patients experience in the early postoperative period following cardiac surgery. Increasingly, the composition and volume of intravenous fluids administered during surgery have been implicated in the development of postoperative acidosis. Intraoperative Cell Salvage (ICS), an autologous blood transfusion technique employed by Cardiac/Perfusion Units to minimize blood loss during surgery, involves the infusion of of one such fluid, 0.9% sodium chloride. The rapid infusion of large volumes of 0.9% sodium chloride has previously been linked with the development of hyperchloraemic acidosis. We hypothesize that the volume of mechanically salvaged of red blood cells re-infused into patients undergoing heart surgery contributes to the acidosis that occurs in the early postoperative period.

To test this, we have designed an observational cohort study to check for correlation between the volume of cell salvaged blood infused during surgery and the severity of postoperative acidosis (which will be assessed using data from routine arterial blood gas samples).

Study Overview

• Status: Unknown
• Conditions: Metabolic Acidosis
• Intervention / Treatment: Procedure: routine administration of 0.9% sodium chloride

• Study Type: Observational
• Enrollment (Anticipated): 60

Contacts and Locations

• Study Contact: Name: Peter R Alston, MBChB, FRCA; Phone Number: +44 131 242 3180; Email: peter.alston@ed.ac.uk
• Study Contact Backup: Name: Maithili M Mehta, BSc (Hons); Phone Number: +44 7341576937; Email: s1003484@sms.ed.ac.uk

Study Locations

• United Kingdom
  • Midlothian
    • Edinburgh, Midlothian, United Kingdom, EH16 4SA
      • Royal Infirmary of Edinburgh
      • Contact: Peter R Alston, MBChB, FRCA; Phone Number: +44 131 242 3180; Email: peter.alston@ed.ac.uk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

All adult patients undergoing elective or emergency cardiovascular surgery at the study site (Royal Infirmary of Edinburgh) during the data collection phase of the project will be approached for consent.

Description

Inclusion Criteria:

• Age ≥ 18 years
• Patients scheduled for cardiac surgery including both on- and off-pump coronary artery bypass grafting surgery, heart valve surgery, septal surgery, and aortic surgery)
• Patients must have consented to participate

Exclusion Criteria:

• Patients under 18 years of age
• Patients who are unable or unwilling to provide informed consent

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Cardiovascular surgery; All adult patients undergoing elective or emergency cardiovascular surgery at the study site	Procedure: routine administration of 0.9% sodium chloride; 0.9% sodium chloride is used as the wash and suspension solution for red blood cells during the Intraoperative red blood cell salvage (ICS) procedure.; Other Names: Baxter 0.9% sodium chloride

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
plasma hydrogen ion concentration	Plasma hydrogen ion concentration is measured by the arterial blood gas analyzer machine, and serves as a direct indicator of plasma acidity at a given time point. Data from two routine blood gas samples are of interest: T1 - baseline measurement taken on insertion of an arterial line immediately after the induction of anaesthesia (i.e. before any fluid infusion has commenced); T2 - postoperative measurement made immediately after patient arrives in ICU (i.e. once all the cell salvaged blood has been transfused)	at the start of surgery (before fluid infusion) and immediately after surgery (after fluid infusion)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
plasma chloride concentration	Plasma chloride concentration is measured by the arterial blood gas analyzer machine. Data from two routine blood gas samples are of interest: T1 - baseline measurement taken on insertion of an arterial line immediately after the induction of anaesthesia (i.e. before any fluid infusion has commenced); T2 - postoperative measurement made immediately after patient arrives in ICU (i.e. once all the cell salvaged blood has been transfused)	at the start of surgery (before fluid infusion) and immediately after surgery (after fluid infusion)
plasma strong ion difference	Plasma strong ion difference can be computed from routine arterial blood gas electrolyte measurements (chloride, lactate, sodium, potassium) using a formula. Strong ion difference serves as an indirect measure of plasma acidity. Data from two routine blood gas samples are of interest: T1 - baseline measurement taken on insertion of an arterial line immediately after the induction of anaesthesia (i.e. before any fluid infusion has commenced); T2 - postoperative measurement made immediately after patient arrives in ICU (i.e. once all the cell salvaged blood has been transfused)	at the start of surgery (before fluid infusion) and immediately after surgery (after fluid infusion)

Collaborators and Investigators

• Sponsor: University of Edinburgh
• Collaborators: NHS Lothian
• Investigators: Principal Investigator: Peter R Alston, MBChB, FRCA, University of Edinburgh

Study record dates

Study Major Dates

• Study Start: July 1, 2016
• Primary Completion (ANTICIPATED): August 1, 2016
• Study Completion (ANTICIPATED): August 1, 2016

Study Registration Dates

• First Submitted: June 10, 2016
• First Submitted That Met QC Criteria: June 10, 2016
• First Posted (ESTIMATE): June 15, 2016

Study Record Updates

• Last Update Posted (ESTIMATE): June 15, 2016
• Last Update Submitted That Met QC Criteria: June 10, 2016
• Last Verified: June 1, 2016

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Metabolic Diseases; Acid-Base Imbalance; Acidosis
• Other Study ID Numbers: AC16077

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES

IPD Plan Description

The findings of the study will be written up as a scientific report, which will be submitted for publication in a peer-reviewed scientific journal and presented at a conference.

At the time of publication/dissemination, individual participant data will be reported as an aggregate.