91999Patients are dying as a result of infusion of too much or too little fluid by inexperienced staff.New doctors have inadequate knowledge and sub-optimal prescribing skillsFluid prescription must be given the same status as drug prescription.
10Walsh et al Ann Roy Coll Surg Engl 2005 Poor fluid management contributed to around half of the deathsSASM Report 2008Errors in fluid prescription are common in hospital practice and are dangerousShaifee et al QJM 200317% of postoperative patients develop morbidity directly related to fluid prescriptionWalsh et al Ann Roy Coll Surg Engl 2005Has anything changed since 1999?
11Fluid Prescribing Left to the most junior member of the team Wide variability in prescribing practicesAbout 26% prescribed > 2L 0.9% saline/dayLobo et al Clin Nutr 2001
12Fife 2012Brief survey of juniors in HDU and anaesthesiaPoor knowledge of maintenance requirementsPoor knowledge of Na/K requirementsNo system for calculating peri-operative fluid requirementsFluid therapy is often poorly taught, poorly understood and poorly done
13Some examples 75 year-old lady Post Hartmanns, 55kg Not well 5 days post-op: SOB, oedematousOn TPN AND IV fluids : >3L/dayNa 130Lungs wetIleusGross peripheral oedemaNeeds fluid restriction; stop IV fluidsGentle diuresis
14Overload in Orthopaedics 80 year-old man: Mild angina and mild aortic stenosis, independent, N U&Es, 60kgOp delayed for 6 days, fasted on and off for 6 days. Minimal food intake.16.5 litres IV fluid in 6 days (requirement approx 1800ml/day = 10.8l), Na day 5 =128Day 7 – surgery – still fasting, more IV fluid,D 8 Na 123 – cardiac failure, pulmonary oedema, angina. Frusemide++D 9 creatinine 300, urea 10. All iatrogenicPREVENT!
15Excess loss/ Inadequate provision 80 yrs, post-Hartmanns – developed high NG losses, 4 litres/day for 1 weekFluid balance on ward not properly addressedDeveloped severe alkalosis on the ward:pH 7.61 and severe dehydration, low Na/KAdmitted to ICU for two days for correction before he could go back to theatre: anastomotic leak discoveredOrthopaedics 80 yr old, 60kg with Alzheimer’s: #NOF 3 litres/5days (maintenance: 9 litres)
164 Audits in FifeLots of patients not getting much fluid, especially in orthopaedicsSome got far too much, especially in surgeryNot enough potassium – all areasFar too much sodium – all areasBUT: Education improves practice
17SHDU Results2/3 of patients got too much sodium, in some cases excessively so (> 800mmol Na on one occasion)On 1/3 of patient–days roughly (+/- 500ml) the right volume of fluid was given, on 1/3 too much, and on 1/3 too littleFewer than 1/2 patients received enough potassium. Excess losses were generally not replaced
18Anaesthetic audit: Results Patients with higher intra-operative fluid volumes experienced more post-op complications as well as more PONV (chest infections, arrhythmias, ileus, low BP, confusion)High volumes of Hartmanns are given peri-operatively and it is often used as a maintenance fluid post-op – it is not one
19Lessons from physiology What should we do?Lessons from physiology
20The right amountof the right fluidat the right time
21Moderation FD Moore & GT Shires, Ann Surg 1967 The objective of medical care is restoration to normal physiology and normal function of organs, with a normal blood volume, functional body water and electrolytes. This can never be achieved by inundation.
22In the distant past... Wounded/sick animal or person No food or water may be available for hours until he drags himself to the waterholeRetains fluid by oliguria and anti-diuresis, trying to maintain blood volumeStress response to trauma mediated by Renin angiotensin aldosterone system (RAAS), ADH and catecholamines
23Catabolic Response to Injury/Illness Sodium and water retention (ADH, RAAS, catecholamines)Capacity of kidneys to excrete water and Na is impairedIncreased potassium excretion (due to RAAS activity and protein catabolism)Decreased urine outputSicker patients have poor concentrating ability – poor excretion of Na and Cl loadCatabolic patients produce more urea which is excreted in preference to Na and Cl and this increases water retention
24What do we often do? We give lots of fluid, lots of sodium chloride Kidneys can’t excrete sodium loadChloride causes renal vasoconstriction and exacerbates fluid retention and oedemaLeaky capillaries in sick patients exacerbate RAAS/ADH activity and oedema worsensWe don’t give much potassiumPotassium depletion reduces ability to excrete sodiumWe don’t give many caloriesCalories help the cells to maintain fluid homeostasis
31The Origins of 0.9% SalineNot a physiological fluid – based on a mistake by a physiologist called Hamburger in 1830sHe thought concentration of salt in blood was 0.9% but it is nearer 0.6%0.9% NaCl is not a maintenance fluidIt has certain specific uses
32The Abuse of Normal Salt Solution George H. Evans, JAMA 1911 “One cannot fail to be impressed with the danger of the utter recklessness with which salt solution is frequently prescribed, particularly in the postoperative period…”“…the disastrous role played by the salt solution is often lost in light of the serious conditions that call forth its use.”
34Hartmanns solution/Ringer’s Lactate Discovered independently by Hartmann and Ringer‘Balanced’ solution i.e. More like the composition of plasma, has lactate as a bufferLess Na and Cl load and the Na load is more effectively excreted with less fluid retention (there still is some), less acidosis and less effect on albumin and Hb than salineIt is a good REPLACEMENT fluid when a patient has lost body fluids
35EvidenceExperiments have shown that in healthy volunteers, infusion of 2 litres of saline results, after 6 hours, in weight gain due to fluid retention, a drop in albumin and Hb, acidosis, poor uop and retention of sodium. 2 litres of Hartmanns is better than saline for all of these parameters, and dextrose is the best in terms of lack of fluid retention and uop.This fluid retention is worse in sick patients.Dextrose-containing maintenance fluids are best but ensure not too much is given – the right amount!
36Post -opOther studies have shown that patients having significant amounts of unnecessary fluid peri-operatively have more complications e.g. poor wound healing, chest infections, slow mobilisation, nausea and vomitingThe fluid given must be tailored to each patient’s situation.
37There is a very narrow range for optimal fluid load
38NHS FifeGuidelines for intravenous fluid and electrolyte prescription in adultsGroup: M.McDougall, S. Oglesby,S. Bennett, A. Doyle, K. Buck, A. Sengupta,L. Clark, J. Hadoke, A. Timmins,K. Spurgeon, M. Clark, A. Rahman,L. Reekie.Based on GIFTASUP guidelines
39Jeremy Powell-Tuck (chair), Peter Gosling, British Consensus Guidelines on Intravenous Fluid Therapy for Adult Surgical PatientsGIFTASUPJeremy Powell-Tuck (chair), Peter Gosling,Dileep N Lobo, Simon P Allison, Gordon L Carlson, Marcus Gore, Andrew J Lewington,Rupert M Pearse, Monty G MythenBAPEN Medical, the Association for Clinical Biochemistry, the Association of Surgeons of Great Britain and Ireland, the Society of Academic and Research Surgery, the Renal Association and the Intensive Care Society.
401. Balanced salt solutions e. g 1.Balanced salt solutions e.g. Ringer’s lactate/acetate or Hartmann’s solution should replace 0.9% saline when crystalloid resuscitation or replacement is indicated except in hypochloraemia 1b 2.Solutions such as 4%/0.18% dextrose/saline and 5% dextrose are important sources of free water for maintenance. Excessive amounts may cause hyponatraemia, especially in the elderly 1b
41Recommendation 3To meet maintenance requirements, patients should receive sodium mmol/day, potassium mmol/day in litres of water by the oral, enteral or parenteral route (or a combination of routes).Additional amounts should be given to correct deficit or continuing losses. Careful monitoring should be undertaken using clinical examination, fluid balance charts and regular weighing, when possible.Evidence level 5
42Questions to ask before prescribing fluid Does my patient need intravenous fluid?Why does my patient need intravenous fluid?How much and which fluid does he need?
43Does he need fluid? May be drinking May be on NG feed/TPN – both of these contain fluid which counts as maintenanceMay be receiving many drug infusions e.g. antibiotics/paracetamol – can amount to 1+ litre/dayHe may only need a bit of maintenance fluidThis calculation should be done for each patient
44Why does he need fluid? Maintenance –water and electrolytes To supply the daily needs –(e.g. 4% dextrose/0.18%saline/KCl)Replacement To replace ongoing lossesknow the content of the fluid!Resuscitation - e.g.colloid/bloodTo correct an intravascular or extracellular volume deficit
45MAINTENANCEIf you were on a desertisland, would you drinkfrom the sea or a stream?0.9% saline is nota maintenance fluid
46Daily Requirements (GIFTASUP) Water ml/kg (30)Sodium approx 1 mmol/kgPotassium approx 1 mmol/kgCalories minimum 400 Calories (i.e. 100 g dextrose)(calories help to deal with electrolytes normally)
47Average Daily Requirements 70 kg man needs: ml H2O70 mmol Na+70 mmol K+70 mmol Cl-50kg man needs 1500 ml H2O50 mmol Na+50 mmol K+50 mmol Cl-
48Properties of Commonly Used Crystalloid Solutions Electrolyte Content(mmol/l)Osmolality (mOsm/kg)pH0.9% NaClNa+ 154Cl- 1543085.0Dextrose (4%)-Saline (0.18%)Na+ 31Cl- 312864.55% DextroseNil2804.0Hartmann’s solutionNa+ 131KCaClHCO3- 292766.5
49MAINTENANCEPrescribe maintenance if not drinking >6hrs4%/0.18% dextrose/saline with 20mmol potassium in 500ml, or 40mmol in 1 litre (1 litre is cheaper). Or no potassiumPrescribe in ml/hr (see table) via a pump.The correct volume of this by weight per day for maintenance will provide roughly the correct amount of sodium and potassium for each patient. Maximum 100ml/hr to avoid hyponatraemia. Do not prescribe x hourly
50PUMPSAt present there are just about enough but distribution is a big problemWe are hoping to get more and distribute them better in the hospitalEach ward will have their own so it is important to keep hold of them and get them back if they leaveIf a patient is on dex/saline they really should have a pump to ensure the correct rate is given.If a patient is on fluids of any kind for >6 hours they should have a pump
51PotassiumA normal serum potassium is not an indication that the patient does not need potassium – it just means that their stores haven’t run out yet.A low potassium means that losses are high and body stores very low.A high potassium may be drug related but commonly is due to acute renal failure – monitor U&Es and do not give extra K.Remember that TPN, NG feed and food contain K
52SodiumWe all need some. However most drugs contain sodium so we don’t need to give a lot in fluids unless the patient is losing it.Causes of a low Na – too much fluid (commonest cause in hospital!) – fluid restrictSIADH inappropriate antidiuretic hormone secretion– pneumonia, brain pathologyHigh Na loss – usually upper GI losses – tend to be obvious
53Fluid overload Recognise clinical signs May need fluid restriction Careful fluid balance and monitoringGentle diuresis – beware of precipitating ARF in a patient whose kidneys may not be working efficiently
54REPLACEMENTLosses should be accounted for with replacement fluid: balanced solution: Hartmanns (Plasma Lyte 148 – may become available, has Mg, no Ca, acetate not lactate)Work out how much patient is losing and replace this with Hartmanns – better to calculate retrospectively and replace.Fluid prescriptions for losses must be reviewed regularly and updated.
55LOSSESUpper GI loss: stomach, small bowel ileostomy/fistula/bile leak: high Na and Cl content – may become hypochloraemic and alkalotic – appropriate to use 0.9%NaClLower GI loss: diarrhoea - lose lots of water and potassium: Hartmanns is appropriate to replace + extra potassium (guide in booklet)
56How much fluid does he need? Weight for maintenance 30ml/kg/24hrsHistory, fasting, losses, sepsis, fluid balance chartsClinical status, current losses, fluid intake, urine outputElectrolytes, Hb (may be raised in dehydration)
58Resuscitation FluidFor severe dehydration, sepsis or blood causing circulatory hypovolaemia and hypotensionUse Hartmanns or colloid, blood/O Negative in emergenciesMay need critical care referral for inotropic support/ invasive monitoringCriteria for Critical Care Referral – on guidanceAlgorithm for fluid challengesElective patientsWill get pre op fluids orallyShould get clear fluids up until 2 hours pre op Cochrane meta analysisEmergency patientsMay need iv maintenance and resuscitative fluidsGive appropiate resuscitation fluidCarbohydrate drinks help to reduce thirst, anxiety, PONVBowel prepOnly when requiredPatient should get iv fluid if NBM
59Fluid challenge 250ml colloid or Hartmanns over 2-5 mins Don’t go away!Looking for improved UOP, improvement in perfusion/BP/HRCan be repeated – if patient still looks hypovolaemic after 2 litres senior help is required – may need inotropes and ICUVery few patients will go into LVF with 250ml fluid (less than a can of coke!)
60ColloidsGelofusine – currently in 0.9%NaCl but will soon be in a balanced solutionAlbumin 4.5%Starch – for specialised use in theatre/ICUSome controversy about which is bestFor your purposes don’t worry about this!
61Summary Remember the three questions Doctors should take time and consult senior if unsurePatients on IV fluids need regular U&EsPatients should be allowed food and drink as soon as possible
62The right amountof the right fluidat the right time