Cesar MellaPediatric Critical Care

IntroductionCase #14 year old male presents to ER.History of vomiting and diarrhea. He has had 10 episodes of vomiting (clear then

yellow tinged) 8 episodes of diarrhea with some mucousy

material in the first few episodes. The diarrhea is now watery and the last few episodes have been red in color. The diarrhea odor is very foul.

He has had a fever T-max 101 degrees at home.

Case #1His parents gave him a sports drink (red

color), and then they tried clear Pedialyte.Continues to have vomiting and diarrhea.He feels weak and tired and he looks slightly

pale at times. He has only urinated twice in the last 15

hours.

Case #1Exam: VS T 38.2 degrees (oral), P 110, R45, BP

90/65, oxygen saturation 100% in room air. Weight 18 kg.

He is alert and cooperative, but not very active. He is not toxic or irritable. His eyes are not

sunken. Oral mucosa is moist but he just vomited. CVS/RS exams are normal except for tachycardia.

His abdomen is soft and non-tender. Bowel sounds are normoactive. He has no inguinal hernias and his testes are normal. His overall color is slightly pale, his capillary refill time is 2 seconds over his chest, and his skin turgor feels somewhat diminished.

Body Water CompositionBody composition is 60% to 75% water. The 60% applies to adults and the 75% applies to

newborns. Younger children have more water than adults. Out of this, about 60% is intracellular and 40% is

extracellular. Of the extracellular fluid, 3/4 is interstitial and

1/4 is circulating as plasma There is also a small percentage known as trans-

cellular water (about 2%).

Total Body WaterTotal Body Water60%60%

Intracellular Water 40%Intracellular Water 40%

ExtracellularExtracellularwater 20%water 20%

Interstitial Interstitial Fluid 15%Fluid 15%

PV 5%PV 5%

Total Body WaterHowever, total blood volume is actually 8% to 9%

of body weight for children and 7% of body weight for adults

This is because the red blood cell elements of blood are not considered to be "body water".

Thus, if plasma consists of 5% of the body weight, a few more percentage points would account for the circulating blood volume (which is larger than the circulating plasma volume).

Normal fluid lossesFluid losses occur routinely through urine, stools,

respiratory vapor and insensible skin losses. Perspiration can exaggerate skin losses.

Illness and exercise can exaggerate respiratory fluid loss through vapor. (Remember tachypneic patients)

Other conditions such as burns, vomiting, diarrhea, hemorrhage, diuretics, etc., can also exaggerate fluid losses.

Normal fluid losses:

Insensible 30-40 cc/kg (skin and lungs)

Urine 60 cc/kg

Stool 10-20 cc/kg

Osmolality of body fluidsDefinition- Solute concentration per unit of

solution (i.e.. serum)Normal: 280 -295 mOsm/lTightly regulated and equal between compartments

Fluid moves from one compartment to the other to maintain osmolality.

Serum Osmolality

2Na + Bun + Blood Glucose 2.8 18

Renal Fluid PhysiologyThe postnatal shift in body fluids is

principally mediated through the kidneys' regulation of water and sodium excretion.

Related to GFR and tubular function. A term newborn's glomerular filtration rate

(GFR) is 25% of an adult's.

Renal Electrolyte and Fluid PhysiologyClinical states that can increase basal fluid

requirements in the infant include:HyperthermiaIncreased evaporative losses from mechanical

ventilationAltered transepithelial losses from premature

gestational age.

Renal PhysiologySimple maneuvers include increasing

basal fluid replacement in infants with hyperthermia or in those placed under bilirubin heating lamps and ensuring that all ventilator tubing is humidified.

The patient's state of hydration, renal function, and osmolar load determine his or her urine output and concentration.

Renal PhysiologyOsmolar load consists of endogenous and

exogenous solutes that the kidney must clear to maintain homeostasis.

The volume of renal water must be sufficient for the kidney to clear the osmolar load given its concentrating capacity.

BW ( kg ) Cal/kg/day

2.5 - 10 10011 - 20

50 (+ 1000)20 +

20 (+ 1500)

1 calorie = amount of heat necessary to increase the temperature of 1g of water from 14.5 to 15.5 degree Centigrade.

Add more calories when metabolic demand is increased; e.g., 12 % for each degree C body temperature increased

Maintenance FluidsMaintenance Fluids

Maintenance Fluids II100 cc/kg for the first 10 kg of body

weight50 cc/kg for the next 10 kg of body20 cc/kg for every kilogram thereafter.

For example, 40kg patient would be:10 x 100= 1000cc10 x 50= 500cc20x 20= 400ccTotal: 1900cc/ 24h

IVFNormal Saline (0.9 %) = 154 mEq/L

½ N/S (0.45%) = 77 mEq/L

1/3 N/S (0.33%) = 51 mEq/L

¼ NS (0.2 %) = 39 mEq/L

Fluid Deficit StatesClinical

Mild Dehydration (5%)Moderate Dehydration (10%)Severe Dehydration (15% or more)

Body Weight

Clinical Dehydration AssessmentExamination Mild Moderate Severe

Percentage 5% 10% 15% or >

Older Child 3% 6% 9% or >

Skin turgor Normal Tenting None

Skin touch Normal Dry Clammy

Buccal Mucosa Moist Dry Cracked

Eyes Normal Deep Set Sunken

Tears Present Reduced None

Fontanelle Flat Soft Sunken

CNS Consolable Irritable Lethargic/Obtunded

Pulse Rate Normal Slightly Increased

Increased

Pulse Quality Normal Weak Feeble/Impalpable

Capillary Refill Normal 2 secs >3secs

Urine Output Normal Decreased Anuric

ORSPreferredCheaperLess InvasiveCan be done at homeBut… needs frequent assessments and is

much slower

Contraindications>10 % DehydrationPO IntoleranceIntractable vomitingAltered Mental statusRapid ongoing losses

IV HydrationNS or LR 20cc/kg is a common starting pointSevere dehydration -> infuse in < 10 minsModerate dehydration can be given 1 hrNS or LR are “isotonic fluids”

Type of FluidsMaintenance ElectrolytesNa is given as 3 meq/ 100 cc of IVFK is given as 2 meq / 100 cc of IVFReplaced evenly over time

Deficit ElectrolytesRapid onset dehydration > ECFProlonged dehydration ECF and ICFECF 140 meq/L NaICF 140 meq/L K

Duration of symptoms<3 days: 80% ECF, 20% ICF> 3days: 60% ECF, 40% ICF

Other FactorsBolusElectrolyte ImbalancesRapid CorrectionsCorrect SlowlyReassessReassess

Numbers to MemorizeMaintenance Fluid Calculations

100/ 50/ 20Maintenance Electrolytes

3 meq Na/ 100cc IVF 2 meq K/ 100 cc IVFBolus 20 cc/kgNormal Osmolarity: 290 mOsm/ L30 cc= 1 ounceDuration of symptoms

<3 days: 80% ECF, 20% ICF> 3days: 60% ECF, 40% ICF

Clinical Cases

Case Study #1HPI:

A 3 month-old is in the PICU for shock following a two day history of fever and irritability. Blood and CSF cultures are positive for Streptococcus pneumoniae.

Hospital course: The urine output had decreased (< 0.5 mL/kg/hr)

over the last 24 hours.What is your differential diagnosis regarding the

cause of the oliguria?

Case Study #1Differential DiagnosisOliguria

1) Pre-Renal (decreased effective renal blood flow) Diminished intravascular volume, cardiac

dysfunction, vasodilatation

2) Renal Acute tubular necrosis, acute renal failure, SIADH, ...

3) Post-Renal Outlet obstruction (intrinsic vs. extrinsic), Foley

catheter occlusion

What laboratory studies would you order?

Case Study #1Laboratory studiesSerum studies

Sodium 126 mEq/L BUN 4 mg/dLChloride 98 mEq/L Creatinine 0.4 mg/dLPotassium 3.7 mEq/L Glucose 129 mg/dLBicarbonate 25 mEq/L Osmolality 260 mosm/kg

Urine studiesSpecific gravity 1.025 Sodium 58 mEq/LOsmolality 645 mosm/kg FeNa 2.4%

What are the primary abnormalities?

Case Study #1Laboratory studiesMajor abnormalities 1) Hyponatremia 2) Oliguria (inappropriately

concentrated urine)

What is the most likely explanation for these findings?

Case Study #1 SIADHSyndrome of Inappropriate Antidiuretic

Hormone (SIADH) Variable etiologyTrauma InfectionPsychosis MalignancyMedications Diabetic ketoacidosisCNS disorders Positive pressure ventilation“Stress”

Case Study #1 SIADHManifestations

By definition, “inappropriate” implies the exclusion of normal physiologic reasons for release of ADH: 1) In response to hypertonicity. 2) In response to life threatening hypotension.

Euvolemia with:1. Hyponatremia2. Oliguria3. Concentrated urine

elevated urine specific gravity “inappropriately” high urine osmolality in face of

hyponatremia4. Normal to high urine sodium excretion

Case Study #1 SIADHDiagnosis

Critical level of suspicion.Demonstration of inappropriately concentrated urine in

face of hyponatremia urine osmolality SG urine sodium excretion ( FeNa)

Be certain to exclude conditions with normal physiologic release of ADH Frequently secondary to decreased perfusion Serum sodium, urine osmolality, urine sodium excretion

(low FeNa) consistent with dehydration or diminished renal blood flow. Look at patient more closely !!

Case Study #1 SIADHTreatment

Fluid restriction. 50-75% of maintenance requirements, be certain to

include oral intake.Daily weights.

Case Study #1The saga continues….Hospital course:

Four hours after beginning fluid restriction, you are called because the patient developed generalized seizures. There is no response to two doses of IV lorazepam (Ativan®) and a loading dose of fosphenytoin (Cerebyx®)

What is the most likely explanation?

Case Study #1The saga continuesSeizure 1) Worsening hyponatremia 2) Intracranial event 3) Meningitis 4) Other electrolyte disturbance 5) Medication 6) Hypertension

What diagnostic studies would you order?

Case Study #1The saga continuesStat labs: Sodium 117 mEq/L

What would you do now?

Case Study #1 Hyponatremic SeizuresTreatment: Hypertonic saline (3% NaCl) infusion

Because patient is symptomatic (seizures), immediately increase serum sodium by 5 mEq/L mEq sodium = (0.6) (Wt in kg) (Desired Na in mEq) = = (0.6) (8kg) (5 mEq increase) = 24 mEq 3% NaCl = 0.5 mEq/L, therefore 24 mEq = 48 mL

To correct sodium to 125 mEq/L, the deficit is equal to (0.6) (weight [kg]) (125- measured sodium) (0.6)(8)(125-117) = 38.4 mEq

Follow the initial 24 mEq by slow infusion of remaining 14.4 mEq (29 mL) over next several hours

This equation can be estimated by (slight underestimate) 1mL/kg of 3% NaCl will raise Na by 1 mEq If you want to raise Na by 5 mEq give 5 mL/kg

Case Study #2HPI:

A 5 month-old girl presents with a one day history of irritability and fever. Mother reports three days of “bad” vomiting and diarrhea.

Home meds:Acetaminophen and ibuprofen for fever

PE: BP 70/40, HR 200, R 60, T38.3 C. Irritable, sunken eyes and fontanel, skin feels “doughy”

No one can obtain IV access after 15 minutes,

What would you do now?

Case Study #2Place intraosseous line

Bolus 40 mL/kg of isotonic saline Reassessment (HR 170, RR 40, BP 75/40)

Serum studiesSodium 164 mEq/L BUN 75 mg/dLChloride 139 mEq/L Creatinine 3.1 mg/dLPotassium 5.5 mEq/L Glucose 101 mg/dLBicarbonate 12 mEq/L

VBG pH 7.07 pCO2 11 pO2 121 HCO3 8

What type of acid/base disorder does this patient have?

What is the most likely explanation of this patient’s acidosis?

Case Study #2Non-anion Gap Metabolic AcidosisAnion GapSodium - (chloride + bicarbonate)Normal 12 +/- 2 mEq/LElevated anion gap consistent with excess

acidNormal anion gap consistent with excess loss

of basePatient’s Anion Gap: 164 - (139 + 12) = 13

1. Normal gap

2. Increased gap

1. Renal “HCO3” losses

2. GI “HCO3” losses

Proximal RTA Distal RTA

Diarrhea“Rectal Tubular Acidosis”

1. Acid prod 2. Acid elimination

MethanolUremiaDKAParaldhydeIEM, IronLactateEthylene GlycolSalicylates

Renal disease

Case Study #3HPI:

A five year old (18 kg) boy was involved in a a motor vehicle crash two days ago. He sustained an isolated head injury with intraventricular hemorrhage and multiple large cerebral contusions. Three hours ago, he had an episode of severe intracranial hypertension (ICP 90 mmHg, MAP 50 mmHg, requiring intravascular volume expansion and epinephrine infusion for hypotension. Over the last two hours, his urine output has increased to 130-150 mL/hour (~ 8mL/kg/hr).

What is your differential diagnosis?What test would you order?

Case Study #3Differential diagnosisPolyuria

1) Central diabetes insipidus Deficient ADH secretion (idiopathic, trauma, pituitary

surgery, hypoxic ischemic encephalopathy)

2) Nephrogenic diabetes insipidus Renal resistance to ADH (X-linked hereditary, chronic

lithium, hypercalcemia, ...)

3) Primary polydipsia (psychogenic) Primary increase in water intake (psychiatric), occasionally

hypothalamic lesion affecting thirst center

4) Solute diuresis Diuretics (lasix, mannitol,..), glucosuria, high protein diets,

post-obstructive uropathy, resolving ATN, ….

Case Study #3Laboratory studiesSerum studies

Sodium 155 mEq/L BUN 13 mg/dLChloride 114 mEq/L Creatinine 0.6 mg/dLPotassium 4.2 mEq/L Glucose 86 mg/dLBicarbonate 22 mEq/L Serum osmolality: 320 mosm/kg

OtherUrine specific gravity 1.005, no glucose.Urine osmolality: 160 mosm/kg

What are the main abnormalities?

Case Study #3Laboratory studiesMajor abnormalities 1) Hypernatremia 2) Polyuria (inappropriately dilute urine)

What is the most likely explanation?

Case Study #3Diabetes InsipidusDiagnosisCentral Diabetes insipidus

1) Polyuria2) Inappropriately dilute urine (urine osmolality < serum

osmolality)

May be seen with midline CNS defectsFrequently observed in patients with severe

intracranial hypertension resulting in herniation and loss of cerebral perfusion

What should you do to treat this child?

Case Study #3Diabetes InsipidusTreatment

Acute: Vasopressin infusion - begin with 0.5 milliunits/kg/hour, double every 15-30 minutes until urine flow controlled

Chronic: DDAVP (desmopressin)Warning

Closely monitor for development of hyponatremia

Case Study #4 HPI:

A six year old, 25 kg, boy with severe asthma (S/P ECMO for a previous exacerbation) presents with a two day history of severe vomiting and diarrhea to the Emergency Department.

Home meds: Albuterol MDI two puffs QID, Salmeterol MDI two puffs

BID, Prednisone 10mg daily, Fluticasone 220 mcg two puffs BID

PE: BP 70/40, HR 168, R 40, T39.0 C. He is very lethargic

(GCS 11). Poor perfusion with cool extremities, mottling, and delayed capillary refill, otherwise no specific system abnormalities.

What is your differential diagnosis? What diagnostic studies would you order?

Case Study #4Differential diagnosisShock

1) Cardiogenic Myocarditis Pericardial effusion

2) Hypovolemic Hemorrhage, excessive GI losses, “3rd spacing”

(burns, sepsis)

3) Distributive Sepsis, anaphylaxis

Case Study #4Laboratory studiesSerum studies

Sodium 130 mEq/L BUN 43 mg/dLChloride 99 mEq/L Creatinine 0.6 mg/dLPotassium 5.7 mEq/L Glucose 48 mg/dLBicarbonate 12 mEq/L

OtherWBC: 13k (60% P, 30% L), HCT 35%, PLT 223kChest radiograph: no abnormalities

What are the electrolyte abnormalities?

Case Study #4DiagnosisMajor abnormalities 1) Hyponatremic dehydration 2) Hypoglycemia 3) Hyperkalemia, mild 4) Acidosis 5) Azotemia

What is the most likely explanation for these findings?

Case Study #4 Adrenal Insufficiency1o adrenal insufficiency (Addison’s disease)

Adrenal gland destruction/dysfunction (ie. autoimmune, hemorrhagic)

most common in infants 5-15 days old Secondary adrenal insufficiency

ACTH deficiency (ie. panhypopituitarism or isolated ACTH)

“Tertiary” or “iatrogenic” Suppression of hypothalamic-pituitary-adrenal

axis (ie. chronic steroid use)

Case Study #4 Adrenal InsufficiencyManifestations

Major hormonal factor precipitating crisis is mineralocorticoid deficiency, not glucocorticoid.

Dehydration, hypotension, shock out of proportion to severity of illness

Nausea, vomiting, abdominal pain, weakness, tiredness, fatigue, anorexia

Unexplained feverHypoglycemia (more common in children and

tertiary)Hyponatremia, hyperkalemia, azotemia

Case Study #4 Adrenal InsufficiencyDiagnosis - critical level of suspicion in all patients

with shock1) Demonstration of inappropriately low cortisol

secretion Basal morning level vs. random “stress” level Significant controversy exists as to what level is adequate

2) Determine whether cortisol deficiency dependent or independent of ACTH secretion. ACTH, cortisol 1o adrenal insufficiency ACTH, cortisol 2nd or tertiary insufficiency

3) Seek a treatable cause What should you do to treat this child?

Case Study #4 Adrenal InsufficiencyTreatment

Do not wait for confirmatory labsFluid resuscitation - isotonic crystalloidTreat hypoglycemiaGlucocorticoid replacement - hydrocortisone in

stress doses - 25-50 mg/m2 (1-2 mg/kg) IV every 6 hours

Consider mineralocorticoid (Florinef®)

Case Study #5HPI:

An eight month old infant with autosomal recessive polycystic kidney disease presents with irritability. She is on nightly peritoneal dialysis at home. The lab calls a panic potassium value of 7.1 mEq/L. The tech states that the sample did not have hemolysis.

What do you do now?

Case Study #5HyperkalemiaTreatment

Immediately recheck serum potassium. Immediately check EKG and treat if EKG

changes are presentAnticipatory – discontinue all sources of

potassium including feeds

The Patient’s EKG Strip:

What is the immediate next step in treatment?

Case Study #5HyperkalemiaCalcium chloride 10-20 mg/kg over 5 minutes; may repeat

x2Antagonism of membrane actions of potassiumFirst treatment!!!Avoid rapid IV push

Shift potassium intracellularlyGlucose 1 gm/kg plus 0.1 unit/kg regular insulinAlkalinize (increase ventilator rate; Sodium bicarbonate

1 mEq/kg IV)Inhaled 2 adrenergic agonist (albuterol)

Removal of potassium from the bodyLoop / thiazide diureticsCation exchange resin: sodium polstyrene sulfonate

(Kayexelate®) 1 gm/kg PO or PR (or both)Dialysis

Case Study #6HPI:

A three year old boy is recovering from septic shock. He received 150 mL/kg in fluid boluses in the first 24 hours of therapy and has developed anasarca. You begin him on a bumetanide infusion (Bumex®) for diuresis. He develops significant generalized weakness and begins to hypoventilate. You notice unifocal premature ventricular beats on his cardiac monitor.

What is your differential diagnosis?What tests would you order?

Case Study #6Laboratory studies Serum studies

Sodium 134 mEq/L BUN 11 mg/dLChloride 98 mEq/L Creatinine 0.4 mg/dLPotassium 2.4 mEq/L Calcium 9.2 mg/dLBicarbonate 27 mEq/L Phosphorus 3.2 mg/dL

OtherEKG: Unifocal PVC’s

What is the main abnormality?

Case Study #6Laboratory studiesMajor abnormality

Hypokalemia

What would you do now?

Case Study #6HypokalemiaTreatment

Oral Safest, although solutions may cause diarrhea

IV Peripheral: do not exceed 40-50 mEq/L potassium -

Avoid temptation to administer potassium by rapid bolus

Central: 0.5 -1 mEq/kg over 1-3 hours, depending on severity

Replace magnesium also if low (25-50 mg/kg MgSO4)

Questions? Comments?