Multiorgan failure, nutrition and PCRRT

Bernhard Frey

Dep. of Intensive Care and Neonatology

University Children‘s Hospital Zürich

4th International Conference on PCRRT

Structure of the talk

A PCRRT in MOF:

Do not focus on technology only

B The benefits of PCRRT in MOF

C Some practical aspects of CVVH

Cascade effects of medical technology

Critically ill child

Missing clinical skills

Fluid overload

Organ dysfunction (lungs, brain, heart)

CVVH

Side effects of CVVH

Deyo RA, Annu Rev Public Health, 2002

A Do not focus on technology only

Side effects of PCRRT (CVVH)

Complications with vascular access

Thrombosis

Infection

Air embolism

Bleeding (anticoagulation)

Increased lactate (Barenbrock M, Kidney, 2000)

Filtration of essential molecules

Systemic inflammatory response syndrome (SIRS)

A Do not focus on technology only

CVVH: Unintended consequencies? No prospective studies demonstrating benefit of

PCRRT (relating to relevant end-points)

Renal replacement therapy independently associated

with increased mortality

(Metnitz P, Intensive Care Med, 2004)

Experience with invasive technologies impacts on

outcome (Tilford JM, Pediatrics, 2000)

Invasive technologies may be dangerous in

„threshold“ countries

A Do not focus on technology only

CVVH: Unintended consequencies ?

0

10

20

30

40

50

60

70

Central Catheters Intubation

Pat

ien

ts [

%]

USA

Latin America

Invasive therapies in low risk patients

(Earle M, Crit Care Med, 1997)

How to avoid PCRRT

Avoid fluid overload

Prevention of ARF in MOF

A Do not focus on technology only

Fluid overload in MOFA Do not focus on technology only

Fluid overload in MOF

Stress, pain, nausea

Vasopressin

Morphine, barbiturates

Capillary leak

A Do not focus on technology only

Fluid overload in MOF

Brain: brain swelling

Lungs: higher fluid balance

independent risk of mortality in ALI

(Sakr Y, Chest, 2005)

A Do not focus on technology only

Fluid overload: brain swelling

A Do not focus on technology only

Fluid overload: cerebral herniation

A Do not focus on technology only

ICP

Intracranial volume

Maintenance fluid

Holliday MA and Segar WE, Pediatrics, 1957:

Fluid requirements calculated by caloric expenditure

However: Sick children need much less fluids:

lower caloric intake

lower urinary excretion

decreased insensible losses

A Do not focus on technology only

How to order maintenance fluids Total body water:

weight, edema/dehydration, fluid balance

Blood volume:

microcirculation, diuresis, heart rate, (CVP, BP)

Electrolytes:

Na

Analysis of:

A Do not focus on technology only

Fluid requirements in ventilated children < 10 kg 50 ml / kg / d > 10 kg 1200 ml / m2 / d

+ extra boluses (NaCl 0.9%) to increase cardiac output

Give enteral feeds instead of „free water drips“

A Do not focus on technology only

Volume to optimize preloadA Do not focus on technology only

(Michard F, Crit Care, 2000)

Prevention of ARF in MOF

Optimize perfusion pressure and O2-delivery

O2-delivery = Cardiac Output x Hb x SaO2

Avoid intraabdominal hypertension

A Do not focus on technology only

Measurement of intraabdominal pressure

A Do not focus on technology only

PCRRT

The benefits of PCRRT in MOFIndication

Fluid overload

ARF

Inadequate nutrition

B Benefits of PCRRT

The benefits of PCRRT in MOF

Commencing PCRRT early may be beneficial

(Goldstein S, Pediatrics, 2001)

B Benefits of PCRRT

Enteral nutrition in PICU

Early enteral nutrition:

decreased length of hospital stay

less infections

improved wound healing

B Benefits of PCRRT

Enteral nutrition in PICU

(Rogers EJ, Nutrition, 2003)

B Benefits of PCRRT

Enteral nutrition in PICU

Energy supply is often inadequate

Reasons: Fluid restriction

Interruption of nutrition

Measures: start enteral feeds early

Give feeds, not water drips

early jejunal nutrition

favor enteral feeds

PCRRT

B Benefits of PCRRT

Practical aspects of PCRRT (CVVH)Vascular access

Nutrition

Drug dosing

(Review: Norma Maxvold, Timothy Bunchman, Crit Care Clin, 2003)

C Practical aspects

Vascular accessC Practical aspects

Neonate, 2.5 kg

MEDCOMP®

7 F, 10 cm

Filling volume: 0.8 + 0.8 ml

Vascular accessNeonate, 2.5 kg

MEDCOMP®

7 F, 10 cm

C Practical aspects

Nutrition in CVVH

The filter is highly permeable to water and other

small molecules:

amino acids

trace elements Double intake

water soluble vitamins

C Practical aspects

Nutrition in CVVH

The net ultrafiltration rate has to be set to allow

adequate nutrition

< 1 year: EBM / infant formula + trace elements + vit.

> 1 year: Formula (Frebini®) + trace elements + vit.

(Whole protein formula)

C Practical aspects

Drug dosing: Factors affecting drug eliminationFactor Importance

Ultrafiltration rate low

Molecular size low

Drug-protein binding high (sieving coeff.)

Volume of distribution high

Physiological elemination high

C Practical aspects

Drug dosing:Drug specific numbers

Sieving coefficient (Sc)

Sc = Cuf / Cp (0 – 1)

Cuf: drug concentration in ultrafiltrate

Cp: drug concentration in plasma

Volume of distribution (Vd)

C Practical aspects

Drug dosing: practical approachClinical signs of response or

intoxication

Drug concentration monitoring (whenever possible)

C Practical aspects