Why Hypotonic Fluids should be banned in Paediatric Practice

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  • 1.Intravenous Fluids in Children NPSA Guidelines Dr Pam Cupples SPAN Meeting Friday the 20th of April 2007 Dunkeld
  • 2.Aims Historical approach to fluid management based on Holliday & Segar’s ‘4/2/1’ formula Problems with hypotonic fluids in the Paediatric Population NPSA guidelines
  • 3.Maintenance Fluid Requirements Maintenance fluid requirements parallel energy metabolism Energy Expenditure - using tables and nomogram Darrow et Pratt, JAMA 1950 Body surface Area – Crawford et al, Pediatrics 1950 Age - Wallace, Am. J. Clin. Path. 1953 Weight – Holliday & Segar, Pediatrics 1957
  • 4.Holliday & Segar’s Formula ‘healthy’ infants and children Energy expenditure at rest and during activity Energy expenditure equated to water requirements 1ml of water required to burn 1 calorie 1.2mls water are consumed 0.2mls water are produced 3mmols/kg of Na 2mmol/kg of K Infants require ~ 100cal/kg/day Older Children ~ 75cal/kg/day Adults ~ 35cal/kg/day Calorie Requirements 100cal/kg/day <10kg 50cal/kg/day 10-20kg 20cal/kg/day >20kg Hypotonic fluid 0.18% NaCl with 4% Dextrose
  • 5.How we got the ‘4-2-1’ rule Calorie Requirements Based on Weight 0-10kg: 100cal/kg/day 10-20kg: 1000cal + 50cal/kg/day for each kg over 10kg > 20kg: 1500cal + 20cal/kg/day for each kg over 20kg Water Requirements – ‘ 4-2-1 rule’ 0-10kg: 100 water/kg/day ( 4ml / kg/ hour) 10-20kg: 1000 water + 50 water/kg/day for each kg over 10kg ( 2ml/kg/hour) > 20kg: 1500 water + 20 water/kg/day for each kg over 20kg (1ml/kg/hour)
  • 6.Holliday & Segar - the flawsThe Maintenance Need for Water in Parenteral Fluid Therapy– Pediatrics 1957 WEIGHT Illner et al 2000 - resting energy expenditure is based on fat free mass Accounts for 80% of the BMR but only 7% of the total body mass Calculating energy expenditure based on weight significantly over estimates the calorie requirements and hence the water requirements
  • 7.Energy Expenditure No allowance for the different energy expenditure in acute disease / post surgery Actual energy expenditure is 50% lower than values used by Holliday & Segar Briassoulis et al, 2000 Lindahl et al, 1988 Lower energy requirements due to : 50% of calorie expenditure allowed for growth Catabolic state Inactivity PICU setting – IPPV / sedated and paralysed Exceptions – fever,sepsis & burns
  • 8.Water Losses Insensible water losses 27ml/kg/day Heeley & Talbot , 1955 50% of this value – Lamke, 1977 Skin 7ml/kg/day Lungs 5ml/kg/day Urinary losses 50-60ml/kg/day Holliday & Segar, 1957 No allowance for non-osmotic stimuli for ADH Stress, pain, surgery, fever Drugs – opioids, NSAIDs Urinary volume reduced to 25ml/kg/day Endogenous water production from tissue catabolism  in acute illness
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  • 10.Hazards of Hypotonic FluidsAcute Hospital Acquired Hyponatraemia Prescription of hypotonic fluids Provision of excess free water in conditions where patient unable to excrete the excess water load Non – osmotic stimuli for ADH
  • 11.Non Osmotic Stimuli for ADH Secretion Stress Pain Post-operative period Sepsis Pyrexia Nausea & vomiting Co-existing medical conditions CNS infections Respiratory disorders Metabolic & endocrine disorders Drugs Morphine NSAID’s SSRI’s Barbiturates Carbamazepine Clofibrate Isoprenaline Chlorpropamide Vincrisitine
  • 12.Hazards of Hypotonic FluidsAcute Hospital Acquired Hyponatraemia Acute Hyponatraemia Na < 136mmols/L occurring within 48 hours Severe hyponatraemia if Na < 130mmols/L Or any level of hyponatraemia associated with clinical signs Risk group Children Premenopausal women Hypoxia Hyponatraemic encephalopathy 50% of children with Na<125mmol/L 8% mortality rate Risk of developing hyponatraemia with hypotonic fluids is 17.2 times than with isotonic fluids Choong et al, 2006 Children have a poorer outcome than adults for a given level of hyponatraemia
  • 13.Acute Hospital Acquired Hyponatraemia – children at risk Common symptoms Headache Nausea & vomiting Weakness Advanced signs Seizures Respiratory arrest Dilated pupils Decorticate posturing Coma Pulmonary oedema
  • 14.Risks of Hypotonic Fluids 50 cited cases of child death or neurological injury in the international literature 4 deaths and 1 ‘near miss’ in the UK since 2000 Post-op setting in previously healthy children Minor surgical procedures
  • 15.Conclusions Hypotonic fluids are not benign but potentially dangerous 17.2 times more likely to develop hyponatraemia with hypotonic fluids than with isotonic Isotonic fluids offer a safe alternative to hypotonic fluids with no risk of hypernatraemia Fluid regimes should be tailored to the individual Appropriate monitoring Weight, baseline U&E’s
  • 16.Background to the NPSA March 2003 – RCA asked by the RCPCh to issue warning re. The use of 0.18% Saline in 4% Dextrose November 2004 – Inquiry set to investigate the deaths of 3 children from hyponatraemia following a documentary Audit in 2004/2005 – few anaesthetists had seen the warning NPSA – advice to healthcare professionals on how to reduce risk develop solutions and introduce them into clinical practice
  • 17.NPSA Plan of Action July 2005 – form an internal working group to assess problem August 2005 – External working group appointed after October to November 2005 – meetings of the external group to discuss evidence collected Dec 2005 – draft of the safe practice recommendations Jan-Feb 2006 – Wide stakeholder consultation on draft April 2006 – publish NPSA guidance
  • 18.NPSA – Patient safety alert 22: Reducing the risk of hyponatraemia when administering intravenous infusions to children (Alert 5 of 5)Applies to all paediatric patients from 1 month to 16 years28th March 2007 Remove 0.18% NaCl / 4%Dextrose from general stock Produce and disseminate clinical guidelines for the fluid management of paediatric patients Adequate training and supervision of staff Reinforce safe practice Promote the recording and reporting of hospital acquired hyponatraemia Audit programme to ensure that the NPSA recommendations are being adhered to
  • 19.NPSA guidelines Template for developing local guidelines for the prescription & monitoring infusions in children Importance of rigorous clinical and laboratory monitoring Prescription of fluids same importance and consideration as other medicines Fluids must be individualised Calculate fluid balance and monitor plasma Na
  • 20.Oral fluids preferable to iv Resuscitation Fluids – bolus of 0.9% saline Deficit – calculated and replaced as 0.9% saline or 0.9% saline with 5% dextrose Replace over 24 hours Maintenance – do not use 0.18% saline with 4% dextrose 0.45%saline with 5% dextrose Children at high risk – only isotonic fluids Peri and post operative Na levels lower end of normal or <135mmol/L Volume depleted Hypotension CNS infection Head injury Bronchiolitis Sepsis Excessive gastric / GI losses Chronic conditions – CF,IDDM Salt wasting syndromes
  • 21.NPSA Guidelines Ongoing losses Assessed 4 hourly Replacement fluid should reflect the type of electrolyte composition of the fluid being lost Isotonic safest choice Monitoring Robust regime Weight of child Baseline and daily measurements of Na, K, urea & Cr More frequent if Na already low or clinical picture changes Training E-modules to assess current level of competencies & knowledge Doctors in training (80-90%) Review their fluid prescriptions IV Prescription Charts Review & redesign – include guidelines on fluid presciptions Monitoring data required How to calculate fluid requirements
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  • 23.www.npsa.nhs.uk/health/alerts
  • 24.Arieff et al, BMJ 1992 Prospective clinical case study 16 children who died or developed permanent neurological damage 0.34% incidence of post-op hyponatraemia (83 affected out of 24,412 patients) 8.4% mortality rate (7 deaths) Halberthal et al, BMJ 2001 23 patients 13 hyponatraemic in post-op period 15 referred to critical care 11 from wards and 4 from other institutes Seizures (18) and vomiting (17) 5 had Rx withdrawn due to brainstem herniation 1 patient sustained permanent, severe neurological damage 16 / 23 receiving maintenance fluids at 50% more than recommended values
  • 25.Paut et al, Ann Fr Anesth Reanim 2000 7 Children 3-6 years ASA 1-2 Scheduled surgical procedures Vomiting, seizures, status or  GCS (5/7) 1 respiratory arrest with Na 120mmol/L All had hypotonic fluids 3/7 IPPV Rx – fluid restriction, NaCl 1 death McRae et al, Int J Pediatr Otorhinolaryngol 1994 3 post-op tonsillectomy patients 2 deaths
  • 26.Choong et al, 2006 Systematic review 6 studies satisified inclusion criteria 2 unmasked RCT 1 non randomised CT 3 observational studies Mean Na in hypotonic group –3.39mmol/L Small number of studies with small group size Total of 404 patients
  • 27.Holliday & Segar 0-10kg: 100cal/kg/day 10-20kg: 1000cal + 50cal/kg/day for each kg over 10kg > 20kg: 1500cal + 20cal/kg/day for each kg over 20kg