basics of fluid therapy zsolt molnár 2009. physiology

Basics of fluid therapy Zsolt Molnár

2009

Physiology

The debt…

• DO2= (SV•P) • (Hb•1.39•SaO2+0.003•PaO2) ~ 1000ml/m (SaO2=100%)

• VO2 = CO • (CaO2 - CvO2) ~ 250 ml/m (ScvO2~70-75%)

CO CaO2

The debt…

• DO2= (SV•P) • (Hb•1.39•SaO2+0.003•PaO2) ~ 1000ml/m (SaO2=100%)

• VO2 = CO • (CaO2 - CvO2) ~ 250 ml/m (ScvO2~70-75%)• A hypovolémiás, vérző beteg:

• Sokk = VO2>DO2

VO2DO2

CO CaO2

Fluid therapy

Infusion fluids and their distribution

TBW ~ 40L

I.st.~15L I.v.~5L0.6xTBV ~ 20L

I. c. E.c.

Coll

NaCl

5%D1/83/84/8

1/43/4

1/1

Fluid compartments

Main considerations

Molnár ‘99

• Distribution:• Water (5%D) in the TBW (1/8)

• Na+ in the e.c. (1/4)

• Colloid in the i.v (1/1)

• Therefore:• 1 L blood loss can be replaced with…

• …4 L isotonic saline, or…

• …1 L colloid.

Infusions

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Signs of hypovolaemia?

• Pulse - MAP

• Capillary refill

• Hourly urine output

• Core – peripheral temperature differance

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• Moderate bleeding

• Sensitivity: 20-30 %McGee S, et al. JAMA 1999; 282: 720

Clinical signs of hypovolaemia

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Start with a Subjective Assessment of Skin Temperature to Identify Hypoperfusion in Intensive Care Unit Patients

Kaplan LJ, et al. J Trauma 2001; 50: 620-7

Cold hands = Hypoperfusion: 39% pos. pred. Cold hand + low HCO3 = Hypoperfusion: 98% pos. pred.

How shall we give it?

Peripheral lines

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• Features• 24 ….14 G

• Color coded» Pink: 20 G

» Green: 18G

» White: 17G

» Grey: 16G

» Orange: 14G

• Simple, fast

• Little complications

Hagen-Poiseuille’s law

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• Importance:• Intravenous fluid replacement

• Airways

• Effective: short &thick

10

4

8

πpp

l

RI

p 0 p 1

l

Rr r+ d r r+ dr r

v v+ dv

Peripheral lines

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• Int. jugular vein– Close to the skin, „far” from the lungs

– Carotid artery can be compressed

• Subclavian vein– Close to the lungs, far from the skin

– Subcl. artery cannot be compressed

• Femoral vein– Far fromthe skin, close to the groin

– Fem. artery can be compressed

Central lines

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• Pain– Use local anaesthesia all the time

• Arterial puncture– Inc ase of clotting disorder – use femoral, jugular approach

• Pneumothorax– Subclavian > int. jugular

• Catheter infection– Femoral > int. jugular > subclavian

– Prevention: regular (7-10 days) change

CVC: complication

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CVC catheter set

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Seldinger’s technique

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US guided puncture

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CVC in the int. jugular vein

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CVC in the subclavian vein

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Position of the tip of the catheter

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Christalloid or colloid?

Mortality

Choi PT et al. Crit Care Med 1999; 27: 200

SAFE

Finfer S et al. SAFE study. N Eng J Med 2004; 350: 2247

SAFE

Finfer S et al. SAFE study. N Eng J Med 2004; 350: 2247

Instead of summary

• „Early Goal-Directed Therapy” (EGDT)Rivers E et al. N Engl J Med 2001; 345: 1368

• Septic patients treated on A&E for 6 hours:– Control group (n=133):

• O2

• CVP: 8-12 mmHg• MAP >65 mmHg

– EGDT group (n=130):• Same as above• ScvO2 > 70% •More fluid, blood

•More dobutamine

Mortality: 46 vs. 30% (p=0.009)

Monitorozás, terápiás végpontok

• Otto Frank, Ernest Starling – 1914: „Law of the heart”– „The mechanical energy set free in the passage from the resting to the

active state is a function of the length of the fiber„

– „Within physiological limits, the force of contraction is directly proportional to the initial length of the muscle fiber”

• Most common reasons of HF:– Reduced circulating volume

– Reduced pump function

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EDV

SV

„End point” of resusscitation

Haemodinamics

Starling EH. The Linacre Lecture on the Law of the Heart. London; 1918Starling EH. J R Army Med Corps. 1920; 34: 258-262

Summary

• Basic physiological knowledge • Read the label!• Fluid therapy is also revolving around: O2

Diagnosis can wait but cells can’t!