Fluid Therapy

FLUID THERAPY Ahmed A Shorrab; MD. Professor of Anesthesia & ICU Mansoura Faculty of Medicine

Goals  Fluid

homeostasis  Consider the volume status  Be able to recognize hypovolemia and formulate a treatment  Know when and which IV fluids to use

Shorrab AA; May 2009

Body Water and Fluid Compartments  TBW

= 0.6 x kg  TBW = ECF + ICF (1/3) (2/3) ECF = extracellular, ICF = intracellular

 ECF

= Interstitial + Plasma (1/3) (1/4)  Fluid spaces are iso-osmolar due to water movement Shorrab AA; May 2009

Body Fluid Compartments

2/3

X 50~70% lean body weight

ICF: 55%~75%

TBW

3/4     

Male (60%) > female (50%) Most concentrated in skeletal muscle TBW=0.6xBW ICF=0.4xBW ECF=0.2xBW

1/3

ECF 1/4

Shorrab AA; May 2009

Extravascular Interstitial fluid Intravascular plasma

Regulation of Fluids Renal sympathetic nerves Renin-angiotensinaldosterone system Atrial natriuretic peptide (ANP)

Shorrab AA; May 2009

Forces acting on the fluid in blood vessels  Oncotic  Hydrostatic

 These

are closely balanced in a well human body.

Shorrab AA; May 2009

Regulation of Fluids

Hydrostatic pressure v.s. Oncotic pressure  Albumin is the major determining oncotic pressure Shorrab AA; May 2009

Shorrab AA; May 2009

Terminology  Osmolality:

a measure of the number of particles dissolved in solution  Tonicity: a measure of the number of “effective” osmoles in solution (for practical purposes, the sodium plus potassium concentration) 

Plasma osmolality=2(Na+K)+Gl/18+U/2.4 280-310 mOsmol/L

Shorrab AA; May 2009

Terminology  Dehydration

Depleted of electrolyte-free water Diagnosis is simple – a high serum sodium concentration  Volume depletion Depleted of isotonic saline Diagnosis by history, physical, and assessment of the patient’s response to therapy Shorrab AA; May 2009

Signs of Hypovolemia    

  

Diminished skin turgor Dry oral mucus membrane Altered mental status Oliguria - <500ml/day - normal: 0.5~1ml/kg/h Tachycardia Hypotension Hypoperfusioncyanosis Shorrab AA; May 2009

Vital Signs are Vital  Urine

output is the most sensitive (first to change) sign of volume contraction  

Poor urine output can be nonspecific Be aware of causes besides volume depletion

 Heart

rate changes second  Blood pressure changes late Shorrab AA; May 2009

Urine output  0.5-1 

mL/kg May be deceptive

  

Oliguria in renal impairment Polyuria in DKA Polyuria in early uraemia

Osmotic diuresis Plasma osmolality=2(Na+K)+Gl/18+U/2.4 Shorrab AA; May 2009

Clinical Diagnosis of Hypovolemia 



   

Thorough history taking: poor intake, GI bleeding…etc BUN : Creatinine > 20 : 1 - BUN↑: hyperalimentation, glucocorticoid therapy, UGI bleeding Increased specific gravity Increased hematocrit Electrolytes imbalance Acid-base disorder Shorrab AA; May 2009

Shorrab AA; May 2009

Fluid Therapy Replacement Maintenance Repair

deficit

Shorrab AA; May 2009

FLUID THERAPY RESUSCITATION

Crystalloid

Colloid

MAINTENANCE

ELECTROLYTES

NUTRITION

1. Replace acute loss 1. Replace normal loss (hemorrhage, GI loss, (IWL + urine+ faecal) 3rd space etc) 2. Nutrition support Shorrab AA; May 2009

Ions in Fluid Compartments

Shorrab AA; May 2009

Electrolyte solutions Plasma

Isotonic solutions

Hypotonic solutions

308 273

278 290

290 278

Normal Ringer’s saline acetate/ lactate Shorrab AA; May 2009

D5

KAEN 3B*

Normal saline  Na

Cl 0.9%  0.9 gm of Na Cl in 100 mL  900 mg in 100 mL  9000 mg in 1L  1mmol = 23 + 35 =58 mg  1L = 9000 / 58 = 154 mmol  Osmolarity 308 mosmol/L  = plasma osmolarity Shorrab AA; May 2009

23

Na11

35

Cl17

Types of IV Fluid solutions  Hypotonic

- 1/2NS  Isotonic - NS, LR, albumen  Hypertonic – Hypertonic saline 2.7%  Crystalloid  Colloid

Shorrab AA; May 2009

The Influence of Colloid & Crystalloid on :Blood Volume Blood volume Infusion volume

20 0 1000 cc

500c c

60 0

100 0

Lactated Ringers

5% Albumin

500c c

6% Hetastarch

500c c

Whole blood Shorrab AA; May 2009

Crystalloids 





Colloids

Isotonic crystalloids - Lactated Ringer’s, 0.9% NaCl - only 25% remain intravascularly Hypertonic saline solutions - 3% NaCl Hypotonic solutions - D5W, 0.45% NaCl - less than 10% remain intravascularly, inadequate for fluid resuscitation





Contain high molecular weight substancesdo not readily migrate across capillary walls Preparations - Albumin: 5%, 25% - Dextran - Gelifundol - Haes-steril 10%

Shorrab AA; May 2009

Fluid Management Goal:  to maintain urine output of 0.5~1.0mg/kg/h  to keep CVP~ 8-12 mmHg  to keep mean BP > 70 mmHg  To keep SpvO2 > 70% GDT, no liberal fluids Shorrab AA; May 2009

Fluid Management Aim  To replace normal losses    

500cc urine Stool Evaporative Respiratory

 Maintenance

for losses  Replace abnormal losses, blood Shorrab AA; May 2009

FLUID SELECTION 

Replace : RA, RL, NS



Maintain: N/2 + D (adult) + K+ 20 mEq N/4 + D (chlldren) + K+ 20 mEq



Repair : NaHCO3 8,4% KCl 25 mEq/25 ml NaCl 3% Shorrab AA; May 2009

For normal losses  Adds

up to 2000-2500cc/day in well adult human; 1-2 ml/kg/h  Can be calculated for a child with formula: 4, 2,1 rule  First 10kg@ 4mL/kg  Second 10kg@ 2mL/kg  More kg@ 1 mL/kg  The sum is multiplied by 24 hrs Shorrab AA; May 2009

Example A child weighing 28 kg needs maintenance fluids over 24 hours as follows  First 10 kg, 10x4= 40 mL  Second 10 kg, 10x2= 20 mL  Remaining 8 kg, 8x1= 8 mL  Total = 68x24 = 1660 mL 1/3 D5 + 2/3 crystalloids Shorrab AA; May 2009

Hypotonic infusion • 5% dextrose

increases ICF > ECF

ICF 660 ml

ISF

Plasma

255 mlShorrab 85 ml AA; May 2009

Replace Normal loss (IWL + urine)

?D5 or not  Not

for volume resuscitation  Safe at concentration of 5% (D5).  If brittle DM, don’t add it, unless treating DKA  Otherwise, it provides a few extra calories 



0.05*1000=50 g dextrose*4kcal/g=200 cal/liter*2L=400 kcal/day in maint fluids. Obviously, this is not enough calories to heal yourself Shorrab AA; May 2009

Abnormal losses& repair  Blood   

Crystalloids, 1ml blood by 3 ml Colloids volume by volume Blood 1ml by 1ml

 Electrolytes  

Na, 1-2 mmol/kg K, 0.5-1 mmol/kg

Shorrab AA; May 2009

Case 1 

 



Healthy 38 yo man in farm accident avulsed his R arm at elbow and bled profusely at the scene. His brother tourniqueted the stump and controlled bleeding after significant blood loss. “Blood everywhere.” VS 96.0 100/60 124 22 Anxious, pale, man acutely ill. Missing R hand, tourniquet in place, cool extremities. What should you do for his fluid status? Shorrab AA; May 2009

Case 1- Basic trauma patient 







He needs 2 large bore IVs Give 2L wide open NS/LR His history is enough to know he can handle a lot of fluid His HCT/Hb will be normal acutely







Use VS and U/O to gauge volume status Follow CK since he has a crush injury from the tourniquet He will need blood, so start early blood resuscitation on him

Shorrab AA; May 2009

Case 2  70

yo woman who has hx of CHF and CRI with several days of changed mental status and poor PO  VS 36.5, 155/88 92 16  Thin, elderly, confused. Lungs: crackles both bases. CV: 3/6 and irreg irreg. No peripheral edema.  What is appropriate from here? Shorrab AA; May 2009

Case 2-unclear volume status  Not

obvious whether she’s wet or dry from the story—CHF + poor PO intake  Be cautious—do further investigation  Use labs, serial exams, chest film  Either try fluids or try diuretics  Adjust your treatment

Shorrab AA; May 2009

Hemotherapy  Oxygen

delivery and oxygen consumption  Compensatory mechanisms during anemia  ↑ cardiac output  changes in oxygen-hgb affinity  Oxygen-hemoglobin

dissociation curve

Shorrab AA; May 2009

Average Blood Volumes  Neonates

Premature  Full-term  Infants  Adults  Men  Women 

95 ml/kg 85 ml/kg 80 ml/kg 75 ml/kg 67 ml/kg Shorrab AA; May 2009

Maximum allowable blood loss  MABL

= EBV x (starting Hct – target Hct) / start Hct

Example  Adult

70kg, Hct 45 allowed to reach 33

EBV = 70 x 70 = 4900 mL = 5L  MABL = 5 x (45 -33) / 45 = 1300 mL

Shorrab AA; May 2009

Transfusion Threshold  According  

15 20% tolerable > 20 % needs trasfusion

 According  

to volume

to Hct

Hct > 30 no transfusion Hct < 30 needs infusion

Shorrab AA; May 2009

Blood typing  Type 

& screen

Predicts compatible transfusion 99.9%

 Cross-matching 

Additional 1% for compatibility

 EMERGENCY

– (pt blood type unknown) give uncross-matched type O

(if 2 or more units transfused then pt should not receive type specific blood later due to risk of hemolysis)

Shorrab AA; May 2009

ABO and Rh compatibility Blood Group

Antigen on Antibodies in RBC serum

Blood group compatibility

A

A

Anti-B

A, O

B

B

Anti-A

B, O

AB

A and B

none

AB,A,B,O

O

none

Anti-A and Anti-B

O only

Rh +

D

none

Rh+ and Rh-

Rh -

none

Anti –D if Shorrab AA; May 2009 sensitized

Rh -

Blood components  Whole

blood

Hct 40%  Use primarily in hemorrhagic shock 

 Packed

red blood cells (PRBCs)

Hct 70-80%  Volume 250-350 ml  Increase adult hemoglobin about 1g/dl 

Shorrab AA; May 2009

Blood components  Fresh  

frozen plasma (FFP)

Contains all coagulation factors except platelets Reversal of warfarin effects, coagulopathy, correct microvascular bleeding

 Platelets 

Treat thrombocytopenia and abnormal function plt

 Cryoprecipitate 

Treat von Willebrand, treat fibrinogen deficits Shorrab AA; May 2009

Risk of blood transfusion  Citrate

intoxication  Acid-base change  Decrease 2,3 –DPG  Hyperkalemia  Dilutional coagulopathy  Volume overload  Hypothermia  Transmission of infection Shorrab AA; May 2009

Immune complication Hemolytic Reactions  Acute hemolytic reaction  Delayed hemolytic reaction  Non-Hemolytic Reactions 

      

Febrile reaction Anaphylaxis, Urticarial reaction Graft vs. Host disease Immune suppression Infectious complications Coagulopathy Citrate toxicity Shorrab AA; May 2009

Types of transfusion  Donor,

with compatible blood  Autologous, own blood withdrawn weeks before re-infusion  Blood salvage, by cell saver devices 



RBCs centrifuged, separated, washed with saline and infused at Hct 40-60 Contraindicated in malignancy.

Shorrab AA; May 2009

Thanks very much

Shorrab AA; May 2009