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Trial registered on ANZCTR


Registration number
ACTRN12619000716167
Ethics application status
Approved
Date submitted
4/04/2019
Date registered
13/05/2019
Date last updated
13/05/2019
Date data sharing statement initially provided
13/05/2019
Date results information initially provided
13/05/2019
Type of registration
Retrospectively registered

Titles & IDs
Public title
The association of high plasma potassium levels and high carbon dioxide levels in patients undergoing major laparoscopic abdominal surgery
Scientific title
The association of high plasma potassium levels and hypercarbia in patients undergoing major laparoscopic abdominal surgery
Secondary ID [1] 297847 0
None
Universal Trial Number (UTN)
U1111-1230-9029
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Hypercarbia 312221 0
Hyperkalaemia 312222 0
Laparoscopic abdominal surgery 312223 0
Condition category
Condition code
Surgery 310767 310767 0 0
Surgical techniques
Anaesthesiology 310768 310768 0 0
Anaesthetics
Blood 310848 310848 0 0
Other blood disorders
Metabolic and Endocrine 310849 310849 0 0
Other metabolic disorders

Intervention/exposure
Study type
Observational
Patient registry
False
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
There is no participant involvement as this is a retrospective review of the patient medical records. Patients undergoing major laparoscopic surgery who develop hypercapnia during surgery will be retrospectively evaluated. From this retrospective cohort we will use the hospital electronic medical record system (CERNER) to identify patients with intraoperative hypercapnia, which will be defined as a partial pressure of arterial carbon dioxide (PaCO2) greater than 45 mmHg.
Intervention code [1] 314086 0
Early Detection / Screening
Comparator / control treatment
Patients undergoing major laparoscopic surgery who do not develop hypercapnia during the surgery will be evaluated. These patients will be defined as having a partial pressure of arterial carbon dioxide (PaCO2) within normal values (PaCO2 35-45 mmHg)
Control group
Active

Outcomes
Primary outcome [1] 319615 0
The intraoperative plasma potassium value will be recorded by an arterial blood gas during surgery. Measurement of plasma potassium levels in arterial blood
will be measured using an ABL 800 Blood Gas Analyser (Radiometer, Copenhagen,
Denmark) with a fully automated micromode eliminating the risk of user induced bias or loss of accuracy with very small samples. The value from the blood gas machine is stored electronically on our hospital's electronic medical record system (Cerner). This value will be extracted onto a data collection form.
Timepoint [1] 319615 0
15 minutes from completion of surgery (i.e last surgical suture).
Secondary outcome [1] 368862 0
Change in plasma potassium levels. The will be calculated as the difference between the first or baseline blood gas potassium value and the potassium value from the blood gas taken 15-minutes from completion of surgery.

The baseline and final blood gas potassium values will be recorded by an arterial blood gas during surgery. Measurement of plasma potassium levels in arterial blood
will be measured using an ABL 800 Blood Gas Analyser (Radiometer, Copenhagen,
Denmark) with a fully automated micromode eliminating the risk of user induced bias or loss of accuracy with very small samples. The value from the blood gas machine is stored electronically on our hospital's electronic medical record system (Cerner).
Timepoint [1] 368862 0
This will be investigated by comparing the change in plasma potassium at completion of surgery compared to the baseline potassium value at start of surgery
Secondary outcome [2] 368863 0
Development of any malignant arrhythmia. Malignant arrhythmia's will be defined as new onset atrial fibrillation, rapid atrial fibrillation (ventricular response rate > 100b/min), supra ventricular tachyarrythmias (narrow or wide complex), severe bradyarrythmias (heart rate less than 40 b/min), and junctional tachycardia, electrocardiographic evident of hyperkalaemia (new onset loss of p-waves, widening SRS complexes, new elevated T-waves). This will be assessed by the continuous 3 lead electrode attached to the patient as apart of standard anaesthesia care. Any arrhythmia is captured automatically by the anaesthesia monitor.
Timepoint [2] 368863 0
During the intraoperative period
Secondary outcome [3] 368864 0
Development of any malignant arrhythmia postoperatively. Malignant arrhythmia's will be defined as new onset atrial fibrillation, rapid atrial fibrillation (ventricular response rate > 100b/min), supra ventricular tachyarrythmias (narrow or wide complex), severe bradyarrythmias (heart rate less than 40 b/min), and junctional tachycardia, electrocardiographic evident of hyperkalaemia (new onset loss of p-waves, widening SRS complexes, new elevated T-waves). This be assessed by 12 lead EEG (electrocardiograph) that will be attached to the patient if there is any concern about the development of a post operative arrhythmia.
Timepoint [3] 368864 0
From completion of surgery to hospital discharge
Secondary outcome [4] 368865 0
Development of any Major Adverse Cardiovascular Events (MACE). The so-called "classical 3-point MACE" will be defined as defined as a composite of nonfatal myocardial infarction, development of heart failure and stroke. This will be assessed from data linkage to the patients electronic medical records (CERNER) and from the patients discharge summary on the electronic medical records.
Timepoint [4] 368865 0
From completion of surgery to hospital discharge
Secondary outcome [5] 368866 0
Other post surgical complications including acute kidney injury, sepsis, wound infection. This will be assessed from data linkage to the patients electronic medical records (CERNER) and from the patients discharge summary on the electronic medical records.
Timepoint [5] 368866 0
Duration of hospital stay
Secondary outcome [6] 368867 0
Length of hospital stay
Timepoint [6] 368867 0
From completion of surgery until hospital discharge. This will be assessed from data linkage to the patients electronic medical records (CERNER) and from the patients discharge summary on the electronic medical records.
Secondary outcome [7] 368868 0
Unexpected admission to ICU. This be be defined as any patient who is discharge to the ward, either from the post-operative anaesthesia recovery unit, the high dependency unit, or from the intensive care unit, who then requires an unexpected or unplanned admission, or re readmission if they have already been to ICU, for the management any altered physiological or haemodynamic states requiring intensive care therapy. This information will be assessed by data linkage to the hospitals electronic medical records.
Timepoint [7] 368868 0
From completion of surgery until hospital discharge
Secondary outcome [8] 368869 0
Medical emergency team (MET) call. At our institution, the MET team is activated whenever a patient meets predetermined criterion, which include acute changes in any of the following: conscious state; airway (noisy breathing/stridor); breathing (respiratory rate <8 or >30 breaths/min; pulse oximetry saturation <90% despite supplemental 10 litres/min oxygen therapy); circulation (heart rate <40 or >130 beats/min; systolic blood pressure <90 mmHg; urine output <50mL in 4 hours); bleeding (>100mL/hr); or if any member of staff is worried about the patient. In addition, an RRT is activated for any “code blue”. A “code blue” is activated whenever a patient suffers a cardiac or respiratory arrest. Once a MET call is activated, this is coded by the hospital clinical informatics unit. Access to this coding will be obtained by data linkage to the hospitals electronic medical records.
Timepoint [8] 368869 0
From completion of surgery until hospital discharge
Secondary outcome [9] 368870 0
Mortality. This will be assessed from data linkage to the patients electronic medical records (CERNER) which captures any mortality within 30 days post surgery.
Timepoint [9] 368870 0
From completion of surgery to 28 days postoperatively

Eligibility
Key inclusion criteria
We will include:
1. adult patients greater than 40 years
2. undergoing major laparoscopic surgical procedure, and
3. require mechanical ventilation in the operating suite, and
4. require an arterial line as part of standard haemodynamic monitoring

Major surgery is defined as surgery greater than 2 hours duration and a hospital stay of at least 1 postoperative night
Minimum age
40 Years
Maximum age
No limit
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
1. Any non laparoscopic abdominal surgery
2. The patient has planned thoracic surgery
3. The patient has planned cardiac surgery
4. The patient is pregnant
5. The patient has planned intracranial neurosurgery

Study design
Purpose
Natural history
Duration
Longitudinal
Selection
Defined population
Timing
Retrospective
Statistical methods / analysis
This is a retrospective observational study comparing hyperkalaemia in hypercarbic and normocarbic patients undergoing major laparoscopic surgery surgery. Continuous data will be tested for normality and measures of central tendency will be compared as means and standard deviations (SD) using the Student t test for normally distributed variables; and as medians with interquartile range (IQR) using the Mann-Whitney U test for non-parametric variables. The primary outcome (plasma potassium levels at completion of surgery) will be made using t-test with Welsh's correction. A two-tailed p-value less than 0.05 will be considered as statistically significant. Logistic regression analysis will also be performed to adjust for baseline imbalances. Statistical analysis will be performed using PRISM 7.03 GraphPad software (La Jolla, CA, USA) and Stata 15 (Statacorp). This study will be reported following the STROBE statement checklist for observational studies.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
VIC
Recruitment hospital [1] 13525 0
Austin Health - Austin Hospital - Heidelberg
Recruitment postcode(s) [1] 26145 0
3084 - Heidelberg

Funding & Sponsors
Funding source category [1] 302370 0
Hospital
Name [1] 302370 0
Austin Health
Address [1] 302370 0
145 Studley Road, Heidlelberg, 3084, Victoria, Australia
Country [1] 302370 0
Australia
Primary sponsor type
Hospital
Name
Austin Health
Address
145 Studley Road, Heidlelberg, 3084, Victoria, Australia
Country
Australia
Secondary sponsor category [1] 302258 0
None
Name [1] 302258 0
Address [1] 302258 0
Country [1] 302258 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 303045 0
Austin Health Research Ethics Commitee
Ethics committee address [1] 303045 0
145 Studley Road, Austin Health, Heidlelberg, 3084, Victoria, Australia
Ethics committee country [1] 303045 0
Australia
Date submitted for ethics approval [1] 303045 0
04/04/2019
Approval date [1] 303045 0
05/04/2019
Ethics approval number [1] 303045 0
LNR/19/Austin/41

Summary
Brief summary
A retrospective observational study evaluating the association of hyperkalaemia in normocarbic and hypercarbic patients who have undergone laparoscopic abdominal surgery at Austin health.

This observational QI project will be conducted by the department of Anaesthesia at Austin Health. There is very limited research exploring the association between hypercarbia and potassium levels in an adult human population. It is known that hypercarbia detected in blood gas sampling correlates to processes that result in serum acidaemia, and it has also been theorized that an acidosis caused by hypercarbia may be related to changes in plasma potassium levels. As part of routine standard care at Austin Health, blood gas sampling is conducted intra-operatively and analysed in theatre using a blood gas analysis machine. Results of these studies are recorded in Austin Health’s electronic medical record system (CERNER).

This retrospective observational study aims to determine the relationship between hypercarbia and hyperkalaemia as there is the potential to developing life-threatening cardiac arrhythmias and cardiac arrest due to electrolyte imbalances.

This study aims to achieve the following objectives:

1) Determination of the relationship between hypercarbia and hyperkalaemia
2) Determine the magnitude of hyperkalaemic change from baseline
3) Detail the subsequent potential clinical impact of hyperkalaemia in patients intraoperatively, and post-operatively
4) Identify any patient factors that contribute to changes in serum potassium that may allow future identification of patient populations at risk of hyperkalaemia.
5) Contribute to the limited human data on hyperkalaemia and acidosis.

As this is a quality improvement project, data will be collected retrospectively, and there will be no change to anaesthesia or surgical care in any way. All data collected has already been collected by normal hospital anaesthesia and surgical processes. No new data will be collected. There will be no clinical or patient contact involved at any time point for this project.

Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 92270 0
A/Prof Laurence Weinberg
Address 92270 0
Department of Anaesthesia, Austin Hospital
145 Studley Road,
Heidelberg, 3084, Victoria
Country 92270 0
Australia
Phone 92270 0
+61 3 9496 5000
Fax 92270 0
+61 3 9459 6421
Email 92270 0
Laurence.Weinberg@austin.org.au
Contact person for public queries
Name 92271 0
A/Prof Laurence Weinberg
Address 92271 0
Department of Anaesthesia, Austin Hospital
145 Studley Road,
Heidelberg, 3084, Victoria
Country 92271 0
Australia
Phone 92271 0
+61 3 9496 5000
Fax 92271 0
+61 3 9459 6421
Email 92271 0
Laurence.Weinberg@austin.org.au
Contact person for scientific queries
Name 92272 0
A/Prof Laurence Weinberg
Address 92272 0
Department of Anaesthesia, Austin Hospital
145 Studley Road,
Heidelberg, 3084, Victoria
Country 92272 0
Australia
Phone 92272 0
+61 3 9496 5000
Fax 92272 0
+61 3 9459 6421
Email 92272 0
Laurence.Weinberg@austin.org.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
De-identified data will be available from the principle investigator upon reasonable request.
What supporting documents are/will be available?
No other documents available
Summary results
Have study results been published in a peer-reviewed journal?
No
Other publications
Have study results been made publicly available in another format?
No
Results – basic reporting
Results – plain English summary