REACTIVE OR PROACTIVE: WHICH IS BEST IN RENAL REPLACEMENT THERAPY PHOSPHATE CONTROL?

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REACTIVE OR PROACTIVE WHICH IS BEST IN RENAL
REPLACEMENT THERAPY PHOSPHATE CONTROL?

• Joanna Campion-Smith
• Gurudutta Venkatesha
• Molly McLaughlin
• Meeta Mallik
• Patrick Davies

On behalf of the Trent Renal Critical Care Network
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Hypophosphataemia is common in critically ill
patients

• Predisposed by
• Malnutrition inadequate body stores
• Sepsis
• Hyperventilation
• Glucose infusions
• Side effects include
• Muscle weakness
• Myocardial dysfunction
• Encephalopathy

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Background

• CRRT fluids
• Bicarbonate-buffered solutions
• Containing
• Calcium
• Magnesium
• Sodium
• Chloride
• Lactate
• Glucose
• /- Potassium

But no phosphate
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Maintenance of normophosphataemia

• A balancing act

Adequate phosphate removal
Prevention of hypophosphataemia
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(No Transcript)
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Two possible solutions
Bolus phosphate correction
Addition of phosphate to CRRT fluids
What happens in the UK? Straw poll of 9 UK
PICUs 7 bolus correct 2 add to CRRT fluids Is
one method better?
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Phosphate stability in CRRT fluids

• Work by Wignell, McLaughlin Davies from our
  unit (poster presentation at this meeting)
• Chemical stability of sodium glycerophosphate in
  CRRT fluids proven up to 48h
• Calcium and bicarbonate also stable

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Aims

• Compare phosphate level stability in CRRT
  patients who had bolus correction vs continuous
  correction
• One previous paediatric study has suggested that
  continuous correction improves phosphate control
  (Santiago et al.)

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Methods

• 2 PICUs
• Same CRRT machine fluids
• Same CRRT protocols
• Different phosphate correction protocols

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Methods

• Retrospective analysis of phosphate control of
  all patients who underwent CRRT during a 13 month
  period

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Study population
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Demographics

• Age
• Mean 3.4 years
• Range 0 13.1 years
• Weight
• Mean 14.8 kg
• Range 2.8 48 kg

• CRRT duration
• Mean 65.3 hours
• Range 0.5 216 hours

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Underlying diagnosis
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Indications for CRRT
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More hypophosphataemic episodes in the bolus group
147 12 hourly blood tests
57 episodes of hypophosphataemia
29 in bolus group (38 normal)
23 in continuous correction group (57 normal)
1 episode per 22.5 hours in the bolus group
1 episode per 31.3 hours in the continuous
correction group
p 0.0019
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More bolus patients hypophosphataemic at 24 hours
Continuous correction group
Bolus group
patients hypophosphataemic at 24 hours
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Depth of hypophosphataemia greater in bolus group
0.77 mmol/l Continuous correction group
0.65 mmol/l Bolus group
p 0.036
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Phosphate level mean variance
Bolus group 0.0808
Continuous correction group 0.0488
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Conclusions Recommendations

• Continuous correction
• Tighter phosphate control
• With fewer hypophosphataemic episodes
• No documented side effects in either group
• We recommend addition of phosphate to CRRT fluids

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References

• Wignell A et al., Is the addition of Phosphate to
  Continuous Venous-Venous Haemofiltration fluids
  safe? (2011)
• Santiago MJ et al., Hypophosphataemia and
  phosphate supplementation during continuous renal
  replacement therapy in children. Kidney
  International (2009) 75, 312-316

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QUESTIONS