2009/8/19 ⼩小港外科 Intern teaching R2 ⿈黃昱豪

Fluid Management in Adults

Surgeon’s Maintenance Fluid

Human beings are built by water......

Male (60%) > female (50%)

⼥女⼈人是⽔水作的？？

Biomedical Importance of WaterHomeostasis (CES)

Water distribution

PH maintenance

Maintain Electrolyte Concentration

Set of Fluid Balance

Depletion (dehydration)

Intoxication (over-hydration)

Osmotic & non osmotic mechanism

Body Fluid Compartments:

ICF: 55%~75%

Intravascular àplasma

X 50~70% lean body weight

Extravascular àInterstitial

fluid

TBW

ECF

3/4

1/4

Male (60%) > female (50%)

TBW(Total Body Water)=0.6xBW

ICF=0.4xBW

ECF=0.2xBW

2/3

1/3

Mr.Iron, 60-Kg male, he has......IVW

Ans: 60Kg x 60%(man) x 1/3(ECF) x 1/4(IV) = 3kg intravascular water (about 3000 ml plasma)

Composition of Body Fluids:

Ca 2+

Mg 2+

K+

Na+

Cl-

PO43-

Organic anion

HCO3-

Protein

0

50

50

100

150

100

150

Cations AnionsEC

FIC

F

Osmolarity = solute/(solute+solvent) Osmolality = solute/solvent (290~310mOsm/L)

Tonicity = effective osmolality Plasma osmolility = 2 x (Na) + (Glucose/18) + (Urea/2.8)

Plasma tonicity = 2 x (Na) + (Glucose/18)

Regulation of Fluids:

Hydrostatic pressure v.s. Oncotic pressure à Albumin is the major determining oncotic pressure

Regulation of Fluids:

Renal sympathetic nerves

Renin-angiotensin-

aldosterone system

Atrial natriuretic peptide (ANP)

Fluid management

intake, produce

output, loss

FLUID REQUIREMENTS

Sources Losses (35ml/kg/day)

Water 1500 ml Urine (0.5~1ml/kg/hr)

1500 ml

Food 800 ml Stool 200 ml

Oxidation 300 ml Skin (12ml/kg/day)

500 ml

Resp. Tract 400 ml

Total 2600 ml Total 2600 ml

Practically Daily Input/Output balance = +500ml

Fluid Management

lMaintenance＋Deficit＋Ongoing loss

Maintenance DeficitOngoing loss

Maintenance fluid

Maintenance Fluid:Water require, Rule:

100-50-20(60kg=2300ml/day) 100ml/kg/d(for 1st 10kg) ＋50ml/kg/d(for 2nd 10kg)＋20ml/kg/d(per add 1 kg)

4-2-1(60kg=100ml/hr=2400ml/day) 4ml/kg/hr(for 1st 10kg) ＋2ml/kg/hr(for 2nd 10kg)＋1ml/kg/hr(per add 1 kg)

1.5ml/kg/hr(60kg=90ml/hr=2160ml/day) Electrolytes require:

- Na+: 2-3mmol/kg/day

- K+: 1~2mmol/kg/day

Glucose supplement(if NPO):

100~150g dextrose/per day

"Two stereoisomers (isomeric molecules whose atomic connectivity is the same but whose atomic arrangement in space is different.) of the aldohexose sugars are known as glucose, only one of which (D-glucose) is biologically active. This form (D-glucose) is often referred to as dextrose monohydrate, or, especially in the food industry, simply dextrose (from dextrorotatory glucose).

Mr.Iron, 60-Kg male, NPO Maintenance Fluid......

1. Daily Na Requirement＝3meq/kg ×60kg＝180meq

Daily K Requirement=1meq/kg ×60kg＝60meq

2. Maintenance water＝2300ml＝2.3L

3. 【Na】of fluid＝180meq÷2.3L＝

78meq/L≒1/2 normal saline

4. 0.9%NaCl＝154meq/L

MAINTENANCE vs. REPLACEMENT

n Maintenance:

• Provide normal daily requirements:

• Water: 2.5 L

• Sodium ½ or ¼ NS

• KCl 40-60 meq

n Example:

D5 ½ NS with KCL 20 meq/L running at 100 ml/hr

Intravenous Fluids:• Crystalloids • Colloids • Blood/blood products and blood

substitutes

Parenteral Fluid Therapy:

Crystalloids:

- contain Na as the main osmotically

active particle

- useful for volume expansion (mainly

interstitial space)

- for maintenance infusion

- correction of electrolyte abnormality

Crystalloids: 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 intra-

vascularly, inadequate for fluid

resuscitation

Colloid Solutions:

Contain high molecular weight

substancesàdo not readily migrate across

capillary walls

Preparations

- Albumin: 5%, 25%

- Dextran

- Gelofusine

- Voluven

Solutions Volumes Na+ K+ Ca2+ Mg2+ Cl- HCO3- Dextrose mOsm/L

ECF 142 4 5 103 27 280-310

Lactated Ringer’s 500 130 4 3 109 28 273

0.9% NaCl 500 154 154 308

0.45% NaCl 500 77 77 154

D5W/D10W 50/100

D2.5/0.45% NaCl 500 77 77 25 406

3% NaCl 513 513 1026

Taita No.3 500 75 12 26 20 285Taita No.4 500 110 20 102 8 300Taita No.5 400 36 18 3 17 100 669

Common parenteral fluid therapy-Crystalloid

Acetate:20 Phosphate:6

Acetate:16 Phosphate:12

Acetate:28 Phosphate:12

Solutions Volumes Na+ K+ Ca2+ Mg2+ Cl- HCO3- Dextrose mOsm/L

ECF 142 4 5 103 27 280-310

6% Hetastarch 500 154 154 310

5% Albumin 250,500 130-160 <2.5 130-16

0 330

25% Albumin 20,50,100 130-16

0 <2.5 130-160 330

Common parenteral fluid therapy-Colloid

The Influence of Colloid & Crystalloid on Blood Volume:

1000cc

500cc

500cc

500cc

200 600 1000

Lactated Ringers

5% Albumin

6% Hetastarch

Whole blood

Blood volumeInfusion volume

Deficits fluid

NPO and other deficits

• NPO deficit =number of hours NPO x maintenance fluid requirement. • Bowel prep may result in up to 1 L fluid

loss.

Third Space Losses• Isotonic transfer of ECF from functional body

fluid compartments to non-functional compartments. • Depends on location and duration of surgical

procedure, amount of tissue trauma, ambient temperature, room ventilation.

Department of Anesthesiology Uniformed Services University of the Health Sciences

Replacing Third Space Losses• Superficial surgical trauma: 1-2 ml/kg/hr

• Minimal Surgical Trauma: 3-4 ml/kg/hr

- head and neck, hernia, knee surgery

• Moderate Surgical Trauma: 5-6 ml/kg/hr

- hysterectomy, chest surgery

• Severe surgical trauma: 8-10 ml/kg/hr (or more)

- AAA repair, nehprectomy

Department of Anesthesiology Uniformed Services University of the Health Sciences

Ongoing loss fluid

• Measurable fluid losses:

• Foley tube

• NG suctioning/vomiting

• ostomy output

• PTGBD, T-tube

• Bleeding

!

!

!

• Unmeasurable fluid losses:

• Fever(Temp of 38.3C~39.4C, >24hr ==>500ml ;>37C, 100~150ml/C)

• Ventilator

• Bleeding

Composition of GI Secretions:Source Volume (ml/24h) Na+* K+ Cl- HCO3

-

Salivary 1500 (500~2000) 10 (2~10) 26 (20~30) 10 (8~18) 30

Stomach 1500 (100~4000) 60 (9~116) 10 (0~32) 130 (8~154) 0

Duodenum 100~2000 140 5 80 0

Ileum 3000 140 (80~150) 5 (2~8) 104 (43~137) 30

Colon 100-9000 60 30 40 0

Pancreas 100-800 140 (113~185) 5 (3~7) 75 (54~95) 115

Bile 50-800 145 (131~164) 5 (3~12) 100 (89~180) 35

* Average concentration: mmol/L

Other factors• Ongoing fluid losses from other sites:

- gastric drainage - ostomy output - diarrhea - PTGBD, T-tube

• Replace volume per volume with crystalloid solutions

Blood Loss

• Replace 3 cc of crystalloid solution per cc of blood loss (crystalloid solutions leave the intravascular space)

• When using blood products or colloids replace blood loss volume per volume

Example• Mr.Michelin, 62 y/o male, 80 kg, for hemicolectomy

• NPO after 2200, surgery at 0800, received bowel prep

• 3 hr. procedure, 500 cc blood loss

• What are his estimated intraoperative fluid requirements?

Example (cont.)• Ans: • Fluid deficit: 1.5 ml/kg/hr x 10 hrs = 1200 ml + 1000

ml for bowel prep = 2200 ml • Maintenance: 1.5 ml/kg/hr x 3hrs = 360mls • Third Space Losses: 6 ml/kg/hr x 3 hrs =1440 mls • Blood Loss: 500ml x 3 = 1500ml • Total = 2200+360+1440+1500=5500mls

Monitor

Hypovolemia

Signs of Hypovolemia: Diminished skin turgor

Dry oral mucus membrane

Oliguria

- <500ml/day

- normal: 0.5~1ml/kg/hr

Tachycardia

Orthostatic hypotension/Hypotension

Hypoperfusionàcyanosis

Altered mental status

Orthostatic Hypotension

• Systolic blood pressure decrease of greater than 20mmHg from supine to standing

• Indicates fluid deficit of 6-8% body weight

- Heart rate should increase as a compensatory measure

- If no increase in heart rate, may indicate autonomic dysfunction or antihypertensive drug therapy

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

Hypervolemia

Signs of Hypervolemia:

Hypertension

Polyuria

Peripheral edema

Wet lung

Jugular vein engorgement

Especially when hypo-albuminemia

Management of Hypervolemia:

Prevention is the best way

Guide fluid therapy with CVP level or

pulmonary wedge pressure

Diuretics

Increase oncotic pressure: FFP or

albumin infusion (may followed by diuretics)

Dialysis

Summary• Fluid therapy is critically important during the

perioperative period. • The most important goal is to maintain hemodynamic

stability and protect vital organs from hypoperfusion (heart, liver, brain, kidneys). • All sources of fluid losses must be accounted for. • Good fluid management goes a long way toward

preventing problems.

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