Добавил:
Upload Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз: Предмет: Файл:
Rajesh_Chawla_-_ICU_Protocols_A_stepwise_approa[1].pdf
Скачиваний:
259
Добавлен:
13.03.2016
Размер:
9.49 Mб
Скачать

Multiorgan Failure

90

 

Sajith Kesavan and Bala Ramachandran

 

A 1-year-old infant was admitted to pediatric intensive care unit (PICU) with fever, shock, and lethargy. After administering ßuid boluses and starting on inotropes, he was intubated and shifted to PICU. Investigations showed leukocytosis and thrombocytopenia with severe metabolic acidosis. Within 6 h of admission, urine output decreased, and he started bleeding from the nasogastric tube. He had persistent tachycardia with cold extremities. Investigations showed persistent metabolic acidosis, elevated liver enzymes, and severe coagulopathy (both prothrombin and partial thromboplastin time were prolonged) with rising serum creatinine.

Multiple organ failure (MOF) deÞned as dysfunction of more than two organs, is quite frequently seen in the PICU associated with high mortality. Mortality increases as the number of organ involved increases. Early and appropriate management involving multiorgan support improves outcome in these patients.

Step 1: Initial resuscitation

The patient should be resuscitated, taking care of airway, breathing, and circulation.

Step 2: Assess renal function

¥Renal dysfunction is deÞned as serum creatinine more than two times the upper limit of normal for age or twofold increase in baseline creatinine.

S. Kesavan, M.D. (*)

Department of Pediatrics Intensive Care Unit, Kanchi Kamakoti Childs Trust Hospital, Chennai, India

e-mail: ksajith120@yahoo.com

B. Ramachandran, M.D., D.A.B.P.

Department of Intensive Care & Emergency Medicine, Kanchi Kamakoti Childs Trust Hospital, Chennai, India

R. Chawla and S. Todi (eds.), ICU Protocols: A stepwise approach,

713

DOI 10.1007/978-81-322-0535-7_90, © Springer India 2012

 

714

 

S. Kesavan and B. Ramachandran

 

 

Table 90.1 ModiÞed pediatric RIFLE criteria

 

 

Serum creatinine criteria

Urine output criteria

Risk

eCCL decreased by 25%

Urine output <0.5 mL/

 

 

Kg/h × 8 h

Injury

eCCL decreased by 50%

Urine output <0.5 mL/

 

 

Kg/h × 16 h

Failure

eCCL decreased by 75% or

Urine output <0.3 mL/

 

eCCL < 35 mL/min/1.73 m2

Kg/h × 24 h or anuria × 12 h

Loss

Persistent failure (>4 weeks)

 

End-stage kidney disease

End-stage kidney disease (>3 months)

eCCL estimated creatinine clearance

 

Table 90.2 ClassiÞcation using renal failure indices

 

 

Prerenal

Renal

Urine sediment

Bland

Broad, brownish granular casts

Urine sodium (mEq/L)

<20

>30

Urine osmolality (mosm/L)

>400

<350

Fractional excretion of Na

<1

>1

¥Intensivists prefer the modiÞed pediatric RIFLE criteria to deÞne and classify acute kidney injury.

¥The acronym RIFLE stands for the increasing severity classesÑrisk, injury, and failureÑand the two outcome classesÑloss and end-stage kidney disease (Table 90.1).

Renal failure can also be classiÞed into prerenal and renal causes by using renal

failure indices (Table 90.2).

Fractional excretion of Na = urine sodium ´ plasma creatinine ´100 plasma sodium ´ urine creatinine

Step 3: Send investigations

¥Urine routine examination

¥Renal function test with electrolytes

¥Urine sodium

¥Urine osmolality

¥Urine-speciÞc gravity

¥Arterial blood gas analysis

¥ECG

90 Multiorgan Failure

715

 

 

Oliguria

No evidence of volume overload or cardiac failure

Evidence of volume overload or cardiac failure

Determine volume status

Restrict fluid (400 mL/m2/24 hours+urine output)

IV normal saline 20 mL/kg over 30 minutes

 

Repeat if in shock

Hypovolemic patient usually voids in 2 hours

If no urine output (intrinsic or postrenal ARF)

Consider diuretics if hemodynamically stable (frusemide 2–4mg/kg single dose)

No urine

Consider continuous infusion of diuretics (frusemide 0.5–1 mg/kg/h)

No urine

Stop diuretics and start fluid restriction (400mL/m2/24 hours+urine output), consider renal replacement therapy early

Fig. 90.1 Algorithm for oliguria

Step 4: Manage renal failure

¥Follow oliguria algorithm (Fig. 90.1).

¥Avoid nephrotoxic drugs.

¥Maintain kidney perfusion with ßuids and inotropesÑjudicious use of ßuids to prevent ßuid overload and further ischemic damage to the kidney.

¥Adjust drug dosages according to eCCL.

¥Use Schwartz formula for calculating glomerular Þltration rate (GFR):

(

2

)

= k ´

height in centimeters

GFR mL / min/1.73m

 

 

serum creatinine

 

 

 

 

where k is 0.33 in preterm infants, 0.45 in infants, and 0.55 in older children.

716

 

 

S. Kesavan and B. Ramachandran

 

 

 

 

 

Table 90.3 Types of dialysis

 

 

 

 

 

 

Use in

 

Volume

 

Type

Complexity

hypotension

EfÞciency

control

Anticoagulation

Peritoneal dialysis

Low

Yes

Moderate

Moderate

No

Intermittent

Moderate

No

High

Moderate

Yes

hemodialysis

 

 

 

 

 

CVVH

Moderate

Yes

Moderate

Good

Yes

CVVHDF

High

Yes

High

Good

Yes

¥Schwartz formula is not accurate in a sick child with rapidly changing physiological status. Measuring creatinine clearance directly by using the following formula is better estimate of GFR:

urine creatinine ´ volume of urine in mL/min

´

1.73

 

body surface area in m2

plasma creatinine

¥In a sick child with oliguria and kidney injury, it is better to assume GFR less than 10 while dosing.

¥Early nutritional supportÑhigh-calorie enteral diet with adequate protein is started early.

¥Try to convert hemodynamically stable oliguric into nonoliguric renal failure if possible by using diuretics.

¥Start renal replacement therapy early.

Step 5: Monitor

¥Hourly intakeÐoutput chart, daily weight if possible

¥Hemodynamic monitoring

¥6th-hourly serum electrolytes, daily renal function test

Step 6: Renal replacement therapy

Indications of renal replacement therapy are as follows:

¥Oliguria/anuria with ßuid overload, refractory to diuretic therapy

¥Persistent hyperkalemia not responding to other measures

¥Severe metabolic acidosis unresponsive to medical management

¥Severe electrolyte abnormality

Types of dialysis (Table 90.3)

¥Intermittent hemodialysis

¥Peritoneal dialysis

¥Continuous renal replacement therapy (CRRT)Ñcontinuous venovenous hemoÞltration (CVVH) or continuous venovenous hemodiaÞltration (CVVHDF)

90 Multiorgan Failure

717

 

 

The choice of renal replacement therapy depends on the clinical circumstances, availability of expertise, good vascular access, size of the child and hemodynamic stability.

A. Peritoneal dialysis is the easiest and most widely used modality.

¥Solute clearance is achieved by diffusion and solvent drag. Fluid removal happens by osmosis.

¥It can be done through a catheter placed at the bedside or the surgically placed Tenckhoff catheter. Dialysate volume of 10Ð20 mL/Kg with dwell time of 30 min to 1 h is a good starting prescription.

¥Increasing the dextrose concentration of the dialysate, increasing dwell volume, shortening the dwell time and doing more cycles help in more ultraÞltrate.

¥Hypertonic dialysate ßuid may cause hyperglycemia and rapid ultraÞltration. Heparin (500 units/mL) may be added to the dialysate ßuid to prevent catheter blockage.

¥Potassium can be added to the PD ßuid to a maximum of 4 mEq/L of PD ßuid if there is hypokalemia.

¥Dialysate can be changed to bicarbonate-based instead of lactate-based if there is severe lactic acidosis.

B.Intermittent hemodialysis is done in hemodynamically stable children.

¥Children with multiorgan dysfunction and shock may not be good candidates for it. The advantage of hemodialysis is the rapid removal of toxins and ultraÞltration of ßuid.

C.CVVH is preferred in hemodynamically unstable children.

¥Care should be taken to minimize the amount of blood in the extracorporeal circuit and blood priming of the hemoÞltration circuit may be necessary at the outset.

¥Fluid removal is adjusted according to the patientÕs clinical state during the treatment.

¥The extracorporeal circuit requires good central venous access, usually via a dual-lumen catheter, to allow the high blood ßows necessary to prevent clotting in the hemoÞlter.

¥Blood volume in the extracorporeal circuit should be less than 10% of the patientÕs circulatory volume. Blood ßow of 6Ð9 mL/Kg/min or 8% of circulating blood volume prevents excessive hemoconcentration in the Þlter.

¥Automated machines with appropriate accuracy are recommended for children for delivering the CRRT prescription safely and have replaced pumpassisted hemoÞltration using volumetric pumps.

¥If only ßuid removal is required, then relatively low rates of Þltration are needed, often referred to as slow continuous ultraÞltration. There will be negligible solute removal under these circumstances.

When more solute clearance is needed in addition to ßuid removal, dialysis component is added to the CVVH to make it CVVHDF.

Соседние файлы в предмете [НЕСОРТИРОВАННОЕ]