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Some slides were taken from: Fluid Management Online Intravenous Fluids: A Clinical Approach JAI RADHAKRISHNAN, MD Division of Nephrology Other references:

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Presentation on theme: "Some slides were taken from: Fluid Management Online Intravenous Fluids: A Clinical Approach JAI RADHAKRISHNAN, MD Division of Nephrology Other references:"— Presentation transcript:

1 Some slides were taken from: Fluid Management Online Intravenous Fluids: A Clinical Approach JAI RADHAKRISHNAN, MD Division of Nephrology Other references: The Washington Manual of Medical Therapeutics 1

2 Outline  Review of normal physiology of fluid and electrolyte flux: Volume of distribution  Concepts of osmolality and tonicity  Types of Intravenous Fluids  Composition of IV Fluids  Types of fluid depletion  Specific clinical examples and treatment 2

3 Composition of Body Fluids  Total Body Water  Male: 60% Female: 50%Difference due to adiposity  Extracellular Fluid25-45%  Plasma (intravascular)25%  Interstitial (extra-vascular)75%  Na, Cl, HCO 3  Intracellular Fluid55-75%  K, organic phosphate esters  Thus, sodium for volume, potassium for cell function! 3

4 Volume of Distribution of Water 60%-Males 50%- Females H2OH2O Solids 4

5 Intracellular (2/3) Extracellular (1/3) Solids 40% of Wt H2OH2OH2OH2O Na 5

6 Intra- vascular 1/4 E.C.F. COMPARTMENTS Interstitial 3/4 H2OH2O H2OH2O Na Colloids & RBC 6

7 “Third Space”  Acute sequestration in a body compartment that is not in equilibrium with ECF  Examples:  Intestinal obstruction  Severe pancreatitis  Peritonitis  Major venous obstruction  Capillary leak syndrome  Burns 7

8 Daily Fluid Balance Intake Insensible Losses (approx 500mL) -Lungs 0.3L -Sweat 0.1 L Urine: 1.0 to 1.5L 8

9 Daily Fluid Balance  Sum of the - Urine output (500-1,500 ml/day) necessary to excrete the daily solute load + - the insensible water losses from the skin and respiratory tract MINUS - Amount of water produced from the endogenous metabolism ( ml/day)  [UO + Insensible water loss] – endogenous metab  = [1, ] – 250 = 1750 mL 9

10 More on Insensible Losses  Insensible losses from skin and respiratory tract depend on respiratory rate, ambient temperature, humidity and body temperature  Water losses increase by ml/day for each degree of body temperature  Fluid loss from sweating: highly variable (100- 2,000 mL/hour) depending on physical activity, ambient and body temperatures  Mechanical ventilation with humidified gases may minimize losses from the respiratory tract 10

11 Other causes of water loss  Gastrointestinal Losses: vary in composition and volume depending on their source  Renal losses of sodium are usually minimal, but maybe significant in diuretic therapy, recovery phase of acute tubular necrosis (ATN), post- obstructive diuresis or mineralocorticoid deficiency  Rapid internal fluid shifts: peritonitis, pancreatitis, extensive burns, severe nephrotic syndrome, ileus or intestinal obstruction, crush injuries, rhabdomyolysis [3 rd SPACING] 11

12 MATH-70 kg male Total body water=60% body wt =0.6X70=42 liters ECF=1/3 0.3X42=13 liters ICF=2/3 0.6 X42=25 liters Blood=1/4 (ECF) 0.25X13=3. 3 liters 12

13 Principles of Treatment  How much volume?  Need to estimate the fluid deficit  Which fluid?  Which fluid compartment is predominantly affected?  Need evaluation of other acid/base/electrolyte/nutrition issues. 13

14 Indications for Prescription of IV Fluids I. Highest priority a) Defend haemodynamics 1. Re-expand a severely contracted ECF volume 2. Prevent a fall in BP when venous tone is low (e.g., anesthesia) b) Return the ICF volume towards normal 14

15 Indications for Prescription of IV Fluids Moderate priority 1. Re-expand a modestly contracted ECF volume  Replace ongoing losses  Avoid oliguria  Giving maintenance fluids to match insensible losses : Match estimated electrolyte-free water loss in sweat and in the GI tract 2. To provide glucose as fuel for the brain e.g. during hypoglycemia 15

16 The IV Fluid Supermarket  Crystalloids  Dextrose in water  D5W  D10W  D50W  Saline  Isotonic (0.9% or “normal”)  Hypotonic (0.45%, 0.25%)  Hypertonic  Combo  D5NM/D5NR  D5NSS  D10NS  Ringer’s lactate “physiologic” (K, HCO3, Mg, Ca)  Colloids  Albumin  5% in NS  25% (Salt Poor)  Dextrans  Hydroxyethyl starch (HES); Hetastarch  Haemaccel  Gelofusine  Blood 16

17 Types of Intravenous Fluids  2 types of fluids that are used for intravenous infusions: crystalloids and colloids.  Crystalloids are aqueous solutions of mineral salts or other water soluble molecules.  Colloids contain larger insoluble molecules (particles suspended in solution), such as gelatin; blood itself is a colloid 17

18 Crystalloids  Intravenous infusion fluids which are composed of solutions of crystalline substances, such as sodium chloride, potassium chloride or glucose. (Water and salts = water and electrolytes) 18

19 What are Colloids?  Colloid is the name given to a microparticulate dispersal of one substance in another.  Colloid vs solution? Colloids are physically separable (they may be separated by ultra- filtration or centrifugation), whereas a solution requires chemical separation such as evaporation or chemical reaction (you cannot filter the sugar out of your tea, nor centrifuge it out). 19

20 Colloids in Medicine  In medicine, the term "colloids” refers to IV fluids formed by a colloidal suspension of large molecules in a water- or saline-based medium.  Suspensions of macromolecules, usually in a saline medium.  These may be physiological (such as 4.5% albumin), semi-synthetic such as succinylated gelatine (which in turn is solubilised bovine), or semi-synthetic such as hydroxyethyl starch 20

21 Colloids  Contain particles which do not readily cross semi- permeable membranes such as the capillary membrane  These large molecules tend to remain in the vascular compartment after infusion > exert an osmotic pressure which tends to keep water in the vascular compartment, thereby helping to expand the circulating blood volume and resist redistribution  Thus the volume infused stays (initially) almost entirely within the intravascular space 21

22 Colloids  Stay in the intravascular compartment for a prolonged period compared to crystalloids  However, leak out of the intravascular space when the capillary permeability significantly changes e.g. severe trauma or sepsis, burns  Until recently they were regarded as the gold standard for intravascular resuscitation (see next slide)  Because of their gelatinous properties they cause platelet dysfunction and interfere with fibrinolysis and coagulation factors (factor VIII) – thus they can cause significant coagulopathy in large volumes. 22

23 Efficacy & Safety of Colloids  Conflicting evidence about their efficacy;  Consensus view: in acute volume replacement, they are no better than crystalloids, and may be harmful in some circumstances.  Foreign proteins such as gelatin or HES may provoke anaphylaxis in rare circumstances.  However, there are strong adherents to their use. 23

24 Colloids versus Crystalloids  Colloids preserve a high colloid osmotic pressure in the blood, while, on the other hand, this parameter is decreased by crystalloids due to hemodilution.  However, there is still controversy to any actual difference in efficacy.  Another difference is that crystalloids generally are much cheaper than colloids. 24

25 Colloids versus Crystalloids for Fluid Resuscitation Evidence Base  Colloids have no clinical advantage compared to crystalloids for fluid resuscitation in critically ill adult or children  Hypo-volemic patients given albumin instead of saline does not reduce mortality  Albumin does not reduce mortality in critically ill patients with burns and hypo-albuminemia 25

26  In children with severe malaria, resuscitation with albumin has lower mortality than resuscitation with saline infusion or Gelofusine/ Gelafundin (HES)  In critical traumatic brain injury treatment with albumin compared to saline is likely to be ineffective or harmful  intensive care serum albumin concentration is irrelevant, outcome is the same with saline or albumin Colloids versus Crystalloids for Fluid Resuscitation 26

27 Properties of IV Fluids The amount of solute in a solution influences two related, but subtly different properties: osmolality and tonicity Osmolality versus tonicity  Osmolality refers to the amt of solute= solute or particle concentration  Tonicity: osmotic effect of the solution in relation to another solution across a semi-permeable membrane.  Osmolality is independent of the context whereas  Tonicity is defined relative to a reference point (usually blood or intracellular osmolality); dependent on whether the solute can pass freely through the cell membrane. 27

28 Osmolality versus tonicity  Solutes that are restricted to the ECF (Na+ and accompanying anions) or the ICF (K+ salts and organic phosphate esters) determine the effective osmolality or tonicity of the compartment 28

29 Tonicity  A complex concept because cell permeability varies with cell type and circumstances.  For example, in a non-diabetic, glucose is s rapidly transported into cells and so exerts little persisting osmotic effect, whereas in an insulin- deficient Type 1 diabetic glucose cannot enter the cells and remains in the intravascular space where it exerts a hypertonic effect. 29

30 Tonicity and Osmolality  Most solutions aim to be iso-osmolar to reduce osmotic damage to blood cells and irritation to the veins  However, a hyperosmolar solution such as 5% glucose with 20mmol KCl can actually be effectively hypotonic as the glucose is rapidly absorbed into the cells leaving only the 20mmol KCl and electrolyte-free water 30

31 Water Balance  [N] Plasma Osmolarity: mOsm/kg  Works within a narrow range  Senses 1-2% tonicity change  To achieve steady state  INTAKE should approximately equal EXCRETION  Intake regulated by thirst receptors  Excretion regulated by AVP 31

32 Presenting the 32

33 Crystalloids  The most commonly used crystalloid fluid is normal saline, a solution of sodium chloride at 0.9% concentration, which is close to the concentration in the blood (isotonic)  Ringer’s lactate or Ringer's acetate is another isotonic solution often used for large-volume fluid replacement 33

34 Crystalloids  A solution of 5% dextrose and water, sometimes called D5W, is often used instead if the patient is at risk for having low glucose or high sodium  The choice of fluids may also depend on the chemical properties of the medications being given. 34

35 35

36 Commonly Used Parenteral Solutions IV SolutionOsmolality (mOsm/kg) [Glucose] (g/L) [Sodium] (mmol/L) [Cl-] (mmol/L) 5% D/W % D/W % D/W % NaCl * % NaCl* % NaCl Lactated Ringer’s** * also available with 5% dextrose ** also contains 4 mmol K+, 1.5 mmol Ca++, 28 mmol lactate 36

37 Saline solutions 0.9% Normal Saline – ‘Salt and water’  Principal fluid used for intravascular resuscitation & replacement of salt loss e.g diarrhea and vomiting  Contains: Na+ 154 mmol/l, K+ - Nil, Cl mmol/l; But K+ is often added  IsoOsmolar compared to normal plasma  Distribution: Stays almost entirely in the Extracellular space Of 1 litre – 750ml ECF; 250ml intravascular fluid  So for 100 ml blood loss – need to give 400ml normal saline [only 25% remains intravascular] 37

38 Total body water ECF=1 literICF=0 Intravascular =1/4 ECF=250 ml 1 Liter 0.9% saline Interstitial=3/4 of ECF=750ml 38

39 0.45 NSS= Half normal saline HYPOtonic saline  Reserved for severe hyperosmolar states (for maintenance fuids) e.g. H.H.S or DKA and severe dehydration  Leads to HYPOnatremia if plasma sodium is normal  May cause rapid reduction in serum sodium if used in excess or infused too rapidly. This may lead to cerebral edema and rarely, central pontine demyelinosis ; Use with caution! 39

40 Hypertonic Saline 1.8, 3.0, 7.0, 7.5 and 10% Saline  Reserved for plasma expansion with colloids  In practice rarely used in general wards; Reserved for high dependency, specialist areas  Distributed almost entirely in the ECF and intravascular space. This leads to an osmotic gradient between the ECF and ICF, causing passage of fluid into the EC space. This fluid distributes itself evenly across the ECF and intravascualr space, in turn leading to intravascular repletion.  Large volumes will cause HYPERnatraemia and Intracelullar dehydration. 40

41 41

42 Glucose solutions 5% Dextrose (often written D5W) – ‘Sugar and Water’  Primarily used to maintain water balance in patients who are not able to take anything by mouth;  Commonly used post-operatively in conjunction with salt retaining fluids i.e saline  Provides some calories [ 10% of daily requirements]  Regarded as ‘electrolyte free’ – contains NO Sodium, Potassium, Chloride or Calcium 42

43 D5W  Distribution: 66% intracellular  When infused is rapidly redistributed into the intracellular space; Less than 10% stays in the intravascular space therefore it is of limited use in fluid resuscitation.  For every 100ml blood loss – need 1000ml dextrose replacement [10% retained in intravascular space]  Common cause of iatrogenic hyponatremia in surgical patient 43

44 1 liter 5% Dextrose (D5W) Total body water=1 liter ECF=1/3 = 300mlICF=2/3 = 700ml Intravascular =1/4 of ECF~75ml 44

45 Total body water ECF=1 literICF=0 Intravascular =1/4 ECF=250 ml 1 Liter D5NM/D5NR Interstitial=3/4 of ECF=750ml 45

46 Colloid: 1 liter 5% Albumin Intravascular=1 liter 46

47 A Comparison of Albumin and Saline for Fluid Resuscitation in the Intensive Care Unit N Engl J Med May 27;350(22):

48 Volume Deficit-Clinical Types  Total body water:  Water loss (diabetes insipidus, osmotic diarrhea)  Extracellular:  Salt and water loss (secretory diarrhea, ascites, edema)  Third spacing  Intravascular:  Acute hemorrhage 48

49 Clinical Diagnosis  Intravascular depletion Hemodynamic effects  BP HR JVP  Cool extremities  Reduced sweating  Dry mucus membranes E.C.F. depletion –Skin turgor, sunken eyeballs –Weight –Hemodynamic effects Water Depletion Thirst Hypernatremia 49

50 Example- GI Bleed A 55 year old patient presents with massive hematemesis (vomiting blood) x 1 hour. He has a history of peptic ulcer disease. Exam: Diaphoretic, normal skin turgor. Supine BP: 120/70 HR 100 Sitting BP: 90/50 HR=140 Lab: Serum Na=140  What is the nature of his fluid deficit ?  What IV fluid resuscitation would you prescribe ?  What do you expect the hematocrit to be : - at presentation ? - after 12 hours of Normal Saline treatment? 50

51 Example-Diarrhea and Vomiting  A 23 year old previously healthy medical student returns from vacation in Boracay with a healthy tan and severe diarrhea and vomiting x 48 hours.  Sunken eyeballs, poor skin turgor and dry mucus membranes  BP 80/70 HR 130 supine.  Labs: Na 130 K=2.8 HCO3 =12 ABG: 7.26/26/100  What is the nature of his fluid deficit ?  What fluid will you prescribe ?  What would happen if D5W were to be used? 51

52 Example-Hyperosmolar State An 85 year old nursing home resident with dementia, and known diabetes was admitted with confusion. Exam: Disoriented, restless initially; then stuporous BP: 110/70 supine 90/70 sitting. Decreased skin turgor. Labs: Na= 150meq/L Wt=50kgs BUN/Cr=50/1.8 = 27 Blood sugar= 1200 mg/dl Hct=45 What is the pathogenesis of her fluid and electrolyte disorder ? How would you treat her ? 52

53 Calculation of Water Deficit Osm (P Na) x volume HealthyDehydrated A 50 kg female with Na=150 Na x Normal Body Water = Na x Current Body Water (140) (NBW?) = 150 x (0.5 x 50=25 liters) NBW (X) = 26.8 liters Water deficit = NBW-CBW= =1.8 liters 53

54 A Cirrhotic A 40-year-old patient with known alcoholic cirrhosis, portal hypertension and ascites is admitted with a rising creatinine. Exam: BP 100/70 (no orthostasis), JVP 5cms, +++ascites, no peripheral edema, +asterixis. BUN=12mg/dL Creat=2mg/dL Alb=2.0g/dL Urine volume has been 200cc/24h. 1.Comment on his fluid status 2.If volume-depleted how would you treat him? 54

55 Example-Post Op Abdominal Distension A 60 year old male with pancreatic carcinoma has undergone total pancreaticoduodenectomy and gastrojejunal bypass. On post-operative day-3 he develops abdominal distension.BP= 110/60 and HR increases from 100 to 130 on sitting. Bowel sounds are absent. Abd XRay reveals multiple fluid levels in the abdomen. N-G suction is initiated. What is the nature of his fluid deficit ? How will you treat ? 55

56 Example-Intubated pt A 64 year old male with severe pneumonia has just been intubated. You were asked to give IVF orders since he has several IV meds. BP= 120/70 and HR – 91 bpm Plasma sodium = 128 mmol/L Potassium – 3.6 mmol/L Adequate urine output Is there a fluid deficit ? What will be your IVF order ? While he is still NPO? On NGT OF feeding? 56

57 Case scenarios 1. Unconscious 25 year old, previously healthy, found inside a locked room 2. Unconscious, known diabetic, diaphoretic, tachycardic, afebrile, BP= 150/90 mm Hg 3. Pt with a Stab wound on the abdomen, BP=80/60 mm Hg, awake, restless 4. IVF to follow for a patient with urosepsis, sodium is 150 mmol/L, weak, BP= 100/70 mm Hg 57

58 A Nutritional Dilemma The patient is being treated with 100ml/hour (5% dextrose in 0.9% saline) Is the caloric supply adequate ? Total volume=100mlx24h=2400ml Total dextrose (5g/100ml)= 5x24=120g/day Total calories= 120g x 4kcals/g=480 kcals. **Use D10W-NS instead** 58

59 Conclusions  Crystalloids are generally adequate for most situations needing fluid management.  The composition of the solution and rate of administration are important when addressing a specific situation.  Colloids may be indicated when more rapid hemodynamic equilibration is required (inadequate data). 59


61 References  Reilly, RF., & Perazella, M.. Acid-Base, Fluids, and Electrolytes (Lange Instant Access). McGraw-Hill Professional  The Washington Manual of Medical Therapeutics  61

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