None listed
Conditions
Brief summary
Atrial fibrillation (AF) is the most common complication after cardiac surgery, with an incidence ranging from 20 to 50%. It represents a potential cause of thromboembolic events, hemodynamic instability and prolonged Intensive Care Unit (ICU) stay. Maintaining a normal blood magnesium concentration may help prevent the onset of atrial fibrillation after cardiac surgery. Previously we performed an assessment of the pharmacokinetics of magnesium administration after cardiothoracic surgery from August, 2016 to April, 2017: “Assessment of Blood and Urine Magnesium Levels in Patients Admitted to the Intensive Care Unit” (HREC: LNR/15/Austin/306). We included 60 patients: 30 patients in the before period who received a bolus of 20 mmol of magnesium sulphate over 1 hour; and 30 patients in the after period who received a bolus of 10 mmol of magnesium sulphate followed by a continuous infusion at 3 mmol/h over 12 hours. In the before period, we found that the loading dose of 20 mmol increased both serum and urinary magnesium concentrations, however the serum concentration returned to pre-intervention levels within 12 hours of observation and the urinary excretion remained elevated. In the after period, the intervention of a loading dose of 10 mmol of magnesium sulphate followed by a continuous infusion was associated with an increase of both the serum and urinary concentrations of magnesium over time. The after-period protocol allowed us to achieve a sustained, safe, and moderately elevated serum magnesium concentration at twice to three times the lowest total magnesium concentration in our laboratory (1.4 to 2.0 mmol/L), which might be expected to deliver a greater chance of AF prevention. As such the management practices associated with magnesium administration in our intensive care unit has changed. The purpose of this project is to evaluate the effect of the new protocol on the incidence of atrial fibrillation in patients who undergo cardiac surgery and are admitted to the intensive care unit. Using a medical record audit design we will evaluate patients treated with the new magnesium protocol with that of a historical control.
Interventions
From 1st October 2017 until 31st March 2018, for all cardiac surgical patients at admission to the ICU following surgery, a loading dose of 10 mmol of magnesium sulphate diluted in 100 mL of saline will be administered intravenously over the period of 1 hour. After the end of the loading dose, a continuous infusion of magnesium sulphate will be commenced at a rate of 3 mmol/h (total extrapolated dose over 24 hours of 82 mmol). The continuous infusion will be maintained during the first 96 hours
From 1st October 2017 until 31st March 2018, for all cardiac surgical patients at admission to the ICU following surgery, a loading dose of 10 mmol of magnesium sulphate diluted in 100 mL of saline will be administered intravenously over the period of 1 hour. After the end of the loading dose, a continuous infusion of magnesium sulphate will be commenced at a rate of 3 mmol/h (total extrapolated dose over 24 hours of 82 mmol). The continuous infusion will be maintained during the first 96 hours of ICU stay or until ICU discharge, whichever occurs first; and we will aim a serum magnesium concentration between 1.5 and 2.0 mmol/L with magnesium level monitoring twice daily.
Sponsors
Austin Health
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Adult (aged 18 years or older) patients who are admitted to the intensive care unit following cardiac surgery.
Exclusion criteria
- known renal impairment - treating intensive care unit consultant feels that it is not in the patient's best interest to be treated with the new magnesium supplementation protocol
Outcome results
None listed