Terapêutica hidro-eletrolítico

em pediatria

Antonio Soutoacasouto@bol.com.br

Médico coordenador

Unidade de Medicina Intensiva Pediátrica

Unidade de Medicina Intensiva Neonatal

Hospital Padre Albino

Professor de Pediatria nível II

Faculdades Integradas Padre Albino

Catanduva / SP

2011

Conceitos básicos

FisiologiaBioquímica das soluções

Íons Intra e Extra Celular

Cell Cytosol (mEq/L) Plasma (mEq/L)

K + 140 4

Na + 12 145

Cl -- 4 116

HCO 3-- 12 24

Anions * 138 9

Mg 2+ 0.8 1.5

Ca 2+ <0.0002 1.8

*Anions include phosphate, sulfate, and proteins with a net negative charge.

10

Serum Osmolality

• Normal: 275 – 295 mOsm/L

Isotonic

• < 275 mOsm/L = Hypotonic

• > 295 mOsm/L = Hypertonic

Total body water

ECF=1 liter ICF=0

Intravascular

=1/4 ECF=250 ml

1 Litro de SF 0.9%

Interstitial=3/4 of

ECF=750ml

1 litro de SG 5%

Total body water=1 liter

ECF=1/3 = 300ml ICF=2/3 = 700ml

Intravascular

=1/4 of ECF~75ml

Indicação de suporte hidro-eletrolíticoendovenoso

•Impossibilidade de uso da VO•Tratamento de distúrbios hidro-eletrolíticos•Necessidade do uso de medicamentos EV

Príncipios para prescrição do suporte hidro-eletrolítico endovenoso

•Quanto volume ?

•Qual solução?

•Doença de base•Condição hidro-eletrolítica•Idade•Peso

Quanto volume?

• Condição hidro-eletrolítica (reposição)

• Necessidades basais (perdas fisiológicas)

• Perdas anormais

Quanto volume?

Necessidades basais

(perdas fisiológicas)

Holliday MA, Segar WE. The maintenance

need for water in parenteral fluid

therapy. Pediatrics 1957;19(5):823-32.

Quanto volume?Holliday MA, Segar WE. The maintenance need for

water in parenteral fluid therapy. Pediatrics

1957;19(5):823-32.

The main factor contributing to the

development of hospital acquired

hyponatremia is routine use of hypotonic

fluids

Excess arginine vasopressin (ADH)

NATURE CLINICAL PRACTICE NEPHROLOGY JULY 2007 VOL 3 NO 7

Patients at greatest risk of developing

hyponatremic encephalopathy

following hypotonic fluid

administration

children,postoperative patients,

brain injury or infection,

pulmonary disease or hypoxemia.

J Pediatr 2004;145:584-7.

Holliday MA, Segar WE. The maintenance need for water in parenteral fluid therapy. Pediatrics 1957;19:823-32.

Standard intravenous maintenance therapy is designed to replace ongoing physiological water losses when oral intake is suspended.

An uncommon exception is the syndrome of inappropriate antidiuretic hormone (SIADH) secretion.

In general, patients who had elevated ADH and were given hypotonic saline did not lower ADH and often remained hyponatremic; those who had elevated ADH and were given isotonic saline did lower ADH and generally were normonatremic

25 of 27 acutely ill children with hyponatremia had elevatedplasma ADH levels.

Acta Pediatr 1996;85:550-3

More children with diarrheal dehydration and elevated ADH levels who were given 0.45% saline [77 mEq/L] became hyponatremic than did those who were given isotonic saline [154 mEq/L].

Neville KA, O’Meara M, Verge CF, Walker JL. Normal saline is betterthan half normal saline for rehydration of children with gastroenteritis. Presentedas poster #866 at the Pediatric Academic Society’s annual meeting,Seattle, Wash 2003.

Prospective studyChildren with meningitis and elevated ADHIsotonic saline plus maintenance or maintenance alone

Those given isotonic saline then maintenance lowered ADH, while those given maintenance alone did not.

J Pediatr 1991;118:996-8

Liberadores não-osmóticos de ADH

• Instabilidade hemodinâmica

• Manutenção da PA (Homeostase)

• Hipotensão , hipovolemia

– Relação exponencial com os níveis de ADH

– Mediada por barorreceptores (atrio, aorta, seio carotídeo)Thrasher TN. Arterial baroreceptors control plasma vasopressin responses to graded hypotension in conscious dogs. Am J Physiol Regul Integr Comp Physiol 2000;278(2):R469-75.

– Angiotensina II estimula a liberação de ADHKeil LC. Release of vasopressin by angiotensin II. Endocrinology 1975;96(4):1063-5.

Liberadores não-osmóticos de ADH

• Doenças pulmonares

• Ventilação mecânica

• Distúrbios neurológicos meningite, encefalite,

tumores, traumaKaplan SL, Feigin RD. The syndrome of inappropriate secretion of

antidiuretic hormone in children with bacterial meningitis. J Pediatr

1978;92(5):758-61.

Liberadores não-osmóticos de ADH

• Hipoglicemia

Baylis PH. Arginine vasopressin response to

insulin-induced hypoglycemia in man. J Clin

Endocrinol Metab 1981;53(5):935-40.

• Hipoxia, hipercarbia

• Estresse, medo, dor

• Postoperatório (íleo)

HipovolemiaHipovolemia

HipotensãoHipotensão

Nausea, Nausea, vomito

vomito

BronquioliteBronquiolite

Postoperat

Postoperatóóriorio

medomedo

dordor

EstresseEstresse

Drogas

Drogas

DoenDoenççasas Respiratorias

Respiratorias

DoenDoenççaa neurolneurolóógicagica

Hipoglicemia

Hipoglicemia

Qual criançainternada não

apresenta riscode SIADH?

ApropriadaApropriada secresecreççãoão de H ADde H AD InapropriadaInapropriada secresecre ççãoão de H ADde H AD

RetenRetenççãoão renal de renal de ááguagua

SoluSoluççãoão hipotônicahipotônica

S G5%S G5%

SG5%/SF0,9% (1/5 SG5%/SF0,9% (1/5 --4/5)4/5)

HyponatremiaHyponatremia

Edema cerebralEdema cerebral

SIHAD / Hiponatremia

Inapropriado nível de ADH Exceso de água livre

HiponatremiaHiponatremia sintomsintomááticatica

Tipicamente

Prescrito por nós !

Hiponatremia sintomática

• Náusea, vomito

• Coma

• Convulsões

• Parada respiratória

• HIC

Hiponatremia sintomática

• Children may be at particular risk for developing hyponatremic encephalopathy

– Higher brain/skull ratio

– ? Impaired ability to regulate brain volume by osmoleextrusion

– Higher risk for hypoxemia

Moritz ML, Ayus JC. Disorders of water metabolism in children: hyponatremia and hypernatremia. Pediatr Rev 2002;23(11):371-80.

Hiponatremia sintomática

Os pacientes podem apresentar

uma rápida evolução dos

sintomas (edema cerebral)

Recommendation

• No routine use of hypotonic fluid in

hospitalized children

• 5% Dextrose/0.9% NaCl or 0.9% NaCl

• Does not apply to

– Premies and neonates

– High risk for fluid overload

– Ongoing free water losses