Contributions
Abstract: PB2471
Type: Publication Only
Background
Electrolyte imbalances are common in allogeneic transplant patients, often secondary to gastrointestinal loss and widespread use of calcineurin inhibitors. Hypokalaemia and hypomagnesaemia puts the patient at risk of cardiac arrythmias. There is often variation in the approach taken to electrolyte replacement. At our transplant unit, there is currently no guideline in place to guide prescribing and administration of magnesium and potassium replacement. This leads to apprehension among junior medical staff and nurses, and may lead to prolonged electrolyte derangement through insufficient replacement. There is also signficiant cost associated with repeated electrolyte replacement and monitoring of serum magnesium and potassium.
Aims
We aimed to review current practice of magnesium and potassium replacement at a major London transplant centre. We also aimed to assess the increment rate for low versus high concentrations of magnesium and potassium replacement, and to draft a departmental guideline.
Methods
We audited prescriptions of magnesium and potassium for allogenic transplant patients between October and December 2017. Historic medication charts and our pathology results system were accessed. Serum levels pre- and post-replacement were recorded and the 24-hour increment calculated.
Results
Prescription charts for 52 patients were reviewed. Ninety-eight prescriptions of intravenous magnesium were found: nine prescriptions (39.8%) of 8mmol, 7 (7.1%) of 16mmol and 51 (52.0%) of 20mmol. Average serum increment was 0.08, 0.174 and 0.26mmol/L respectively. There was no significant difference in the serum levels pre-replacement between groups, ranging from 0.44 to 0.77 mmol/L. Oral magnesium replacement was not used. For intravenous potassium chloride, 138 prescriptions were found. Patients had pre-replacement levels between 2.4 and 3.9mmol/L. Oral potassium replacement was concomitantly prescribed in 40 cases (28.99%). There were 102 prescriptions for 40mmol potassium, one for 60mmol, 29 for 80 mmol, four for 120mmol and one for 160mmol. The average serum potassium increment at 24 hours was 0.259mmol/L with 40mmol, 0.3 with 60mmol, 0.6 with 80 mmol, 0.85 with 120mmol and 1.1 with 160 mmol. Post-replacement serum potassium was never higher than 4.9mmol/L. Serum magnesium level was checked in 100 of the cases requiring intravenous potassium replacement (72.5%); 75 of these also required magnesium replacement, 30.7% were prescribed only 8mmol.
Conclusion
We demonstrate that the approach to treatment of hypomagnaesaemia and hypokalaemia at our transplant unit varies significatly. There is a limited increase in serum magnesium level with intravenous doses less than 20mmol, yet lower doses than this are frequently administered. Correction of hypomagnesaemia is also often inadequate in patients with concomitant hypokalaemia. We also demonstrate that increment in serum potassium is limited with doses lower than 80mmol and that it is safe to administer this amount of potassium in hypokalaemic patients without risk of iatrogenic hyperkalaemia. We propose creating a guideline that recommends immediate administration of these higher doses of magnesium sulfate and potassium chloride. We recommend immediate use of 20mmol intravenous magnesium indeficient patients. We also recommed administration of 80mmol potassium if serum concentration is less than 3.0mmol/L. This would minimise risk of arrhythmias and lower the cost of repeated monitoring and administration.
Session topic: 23. Stem cell transplantation - Clinical
Keyword(s): Allogeneic stem cell transplant, Allograft, Transplant
Abstract: PB2471
Type: Publication Only
Background
Electrolyte imbalances are common in allogeneic transplant patients, often secondary to gastrointestinal loss and widespread use of calcineurin inhibitors. Hypokalaemia and hypomagnesaemia puts the patient at risk of cardiac arrythmias. There is often variation in the approach taken to electrolyte replacement. At our transplant unit, there is currently no guideline in place to guide prescribing and administration of magnesium and potassium replacement. This leads to apprehension among junior medical staff and nurses, and may lead to prolonged electrolyte derangement through insufficient replacement. There is also signficiant cost associated with repeated electrolyte replacement and monitoring of serum magnesium and potassium.
Aims
We aimed to review current practice of magnesium and potassium replacement at a major London transplant centre. We also aimed to assess the increment rate for low versus high concentrations of magnesium and potassium replacement, and to draft a departmental guideline.
Methods
We audited prescriptions of magnesium and potassium for allogenic transplant patients between October and December 2017. Historic medication charts and our pathology results system were accessed. Serum levels pre- and post-replacement were recorded and the 24-hour increment calculated.
Results
Prescription charts for 52 patients were reviewed. Ninety-eight prescriptions of intravenous magnesium were found: nine prescriptions (39.8%) of 8mmol, 7 (7.1%) of 16mmol and 51 (52.0%) of 20mmol. Average serum increment was 0.08, 0.174 and 0.26mmol/L respectively. There was no significant difference in the serum levels pre-replacement between groups, ranging from 0.44 to 0.77 mmol/L. Oral magnesium replacement was not used. For intravenous potassium chloride, 138 prescriptions were found. Patients had pre-replacement levels between 2.4 and 3.9mmol/L. Oral potassium replacement was concomitantly prescribed in 40 cases (28.99%). There were 102 prescriptions for 40mmol potassium, one for 60mmol, 29 for 80 mmol, four for 120mmol and one for 160mmol. The average serum potassium increment at 24 hours was 0.259mmol/L with 40mmol, 0.3 with 60mmol, 0.6 with 80 mmol, 0.85 with 120mmol and 1.1 with 160 mmol. Post-replacement serum potassium was never higher than 4.9mmol/L. Serum magnesium level was checked in 100 of the cases requiring intravenous potassium replacement (72.5%); 75 of these also required magnesium replacement, 30.7% were prescribed only 8mmol.
Conclusion
We demonstrate that the approach to treatment of hypomagnaesaemia and hypokalaemia at our transplant unit varies significatly. There is a limited increase in serum magnesium level with intravenous doses less than 20mmol, yet lower doses than this are frequently administered. Correction of hypomagnesaemia is also often inadequate in patients with concomitant hypokalaemia. We also demonstrate that increment in serum potassium is limited with doses lower than 80mmol and that it is safe to administer this amount of potassium in hypokalaemic patients without risk of iatrogenic hyperkalaemia. We propose creating a guideline that recommends immediate administration of these higher doses of magnesium sulfate and potassium chloride. We recommend immediate use of 20mmol intravenous magnesium indeficient patients. We also recommed administration of 80mmol potassium if serum concentration is less than 3.0mmol/L. This would minimise risk of arrhythmias and lower the cost of repeated monitoring and administration.
Session topic: 23. Stem cell transplantation - Clinical
Keyword(s): Allogeneic stem cell transplant, Allograft, Transplant