MUDr. Štefan Trenkler, PhD.I. KAIM UPJS LF a UNLP Košice

Water balance, infusions

Košice 2012

Distribution of body fluids and the Na & K concentrations in the body water

compartments

Lobo DN: Physiological Aspects of Fluid and Electrolyte Balance, 2002 42 l = 28 + 14 (3,5 + 10,5) litres

DAILY WATER BALANCE IN ADULTS WATER INTAKE

Water intake in form of fluids (volumes of drinks including soups)

1000-1500 ml

Water intake in form of semi-solid and solid foods

700 ml

Water of oxidation 300 ml Total daily water intake 2000-2500 ml WATER OUTPUT

water loss in urine 1000-1500 ml water loss through skin 500 ml

water loss through lungs 400 ml water loss in stools 100 ml

Total daily output 2000-2500 ml

Fluid balance

ADDITIONS TO MINIMUM WATER REQUIREMENT, DEPENDING ON CLINICAL SITUATION IN ADULTS

(osmotic free water)

- temperature elevation by 1 oC - moderate sweating - marked sweating, high fever - hyperventilation - hyperventilation in very dry surroundings - exposed wound surfaces and body cavities

(operation lasting up to 5 hours)

100-300 ml 500 ml

1000-1500 ml 500 ml

1000-1500 ml 500-3000 ml

Water, electrolytes homeostasis

• Adequate volume of circulating plasma = normal tissue perfusion

• ECF volume ~ total body Na+ content• Kidney – filtration, reabsorbtion of

water, Na+

• Hormones – renin, aldosteron, ADH; ANP

• Potassium

Na+: 1,5 mmol/kg/dK+: 1 mmol/kg/d

Homeostasis disturbances

• Water – hyper and dehydratation• Osmolality (Na) – hyper a

hypoosmolality• Oncotic disturbances • Ions disturbances• ABG disturbances

Osmotic pressure

Osmotic pressure is force per area that prevents water from passing through membrane!

Osmotic pressure (e.g. erytrocyte)

LABORATORY FINDINGS IN DISORDERS OF WATER BALANCE Disorder Na

mmol/l MCHC

g/l Protein

g/l Hb

mmol/l Hct %

RCC T/l

MCV fl

Normal range 135-145 320-360M 300-340F

65-80 8,7-11,2M

7,4-9,9F

40-48M 36-42F

4,5-6,1M 4,1-5,3F

82-93

Hypotonic dehydration

Isotonic dehydration

n n n

Hypertonic dehydration

Hypotonic overhydration

Isotonic overhydration

n n n

Hypertonic overhydration

If isotonic dehydration is caused by blood loss, total protein, RCC, Hb and Hct are normal or low. If isotonic dehydration is caused by plasma loss, total protein is normal or low. MCHC = mean (erythrocyte) cellular haemoglobin concentration, Hb = haemoglobin, Hct = haematocrit, RCC = red cell count, MCV = mean (erythrocyte) cellular volume,

Fluid inputMaintaining the IC and EC fluid volume

1. Basic requirements (30 ml/kg/d)(1000 ml NS 0.9%; 2000 ml free water (Glu); 60 mmol KCl)

2. Pre-existing deficit (signs of dehydratation/hypovolemia - assessment)

3. Additional losses

Hydratation status, intravascular volume assessment

• History• Physical examination (P, BP, RR, CR,

MM, diuresis)• Tests results (Na, K, osmolality, HTC,

urea)• Patient response to the fluid

administration (physiological parameters)(10 – 20 ml NS 0.9%/kg)

Hypovolemia (fluid depletion)

• Hypotension MAP<65 mm Hg, tachykardia

Diuresis body weight• MAC (MLAC) CVP PAWP LVEDP (TEE)

Distribution of infused fluids in the body water compartments

Lobo DN: Physiological Aspects of Fluid and Electrolyte Balance, 2002

Crystalloids composition

[mmol/l] K Na Cl Ca HPO4 HCO3 Mg kJ kcal inéF1/1 154 154F1/2 77 77 428 103 G 25 gRinger 4 147 156 2,3Ringer L 5,4 130 112 1,8 Lt 27Hartmann 5,4 130 112 1,8 2 Lt 30Darrow 36 120 104 Lt 52Plasmalyte 4 140 98G 5% 855 205 G 50 gG 10% 1710 410 G 100 gArgininCl 21% 1000NaHCO3 8,4% 1000 1000

Colloids

Natural

• Plasma 5 % (frozen)

• Albumin 4,5 %, 20 %

Synthetic

Gelatine Dextran 40, 70 Hydroxyetylstarch

– HAES, Voluven,

Crystalloids vs colloids

• No differences in clinical outcome• More oedema with crystalloids• More rapid replacement with colloids

(permeability)• Risk vs benefit; cost• Newer (better) HEAS?• Mixture of C&C

Fluid replacement

Loss of 1 liter of blood:

Replacement: 1 l of blood or 1 l of colloid (IV)

or 4 l of crystalloid (EC)

or 12 l of glucose (IV + EC + IC)

Distribution volumes of fluids!

Speed of loosesReplace what is lostVolume vs haemoglobinOral/GI route has preference!!!

Guidelines for transfusion of red cells

AAGBI 2001

• Normally patients should not be not transfused if the haemoglobin concentration is >100 g/l.

• A strong indication for transfusion is a haemoglobin concentration <70 g/l.

• Transfusion will become essential when the haemoglobin concentration decreases to 50 g/l.

• A haemoglobin concentration between 80 and 100 g/l is a safe level even for those patients with significant cardiorespiratory disease.

• Symptomatic patients should be transfused

Transfusion trigger

• HB (g/L) Clinical situation

• 100 Acute coronary syndrome• 90 Stabile heart failure• 80 Aged, vascular surgery, sepsis• 70 All other patients

Blood transfusions

• In the meantime – complex decision; prudent and conservative management, based on: - awareness of risks - individual haemoglobin level (70-100 g/L) - clinical judgement based on the sound understanding of the normal and pathological physiology - normovolaemia

• Unit-by-unit basis (1 u ~ 15 g/l), re-evaluation• Departmental/hospital guidelines; regular audit• Haemovigilance system

Fluid regime

1. Preoperative deficits2. Maintenance fluids3. Blood loss4. Losses to the third space

Situation

• Blood volume: • 70 ml x 80 kg = 5600 ml

• Blood loss:• 20% ~ 25-30 g/l = 90 g/l

• End