kevin m creamer m d pediatric critical care walter reed amc l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
PICU Primer I PowerPoint Presentation
Download Presentation
PICU Primer I

Loading in 2 Seconds...

play fullscreen
1 / 55

PICU Primer I - PowerPoint PPT Presentation


  • 257 Views
  • Uploaded on

Kevin M. Creamer M.D. Pediatric Critical Care Walter Reed AMC. PICU Primer I. Physiology Hypoxia / Hypoxemia ABG’s and Acidosis Sodium and H 2 O metabolism Hemodynamics and Cardiopulmonary interactions. ICU Care & Common Problems Head trauma Toxicology Postoperative issues

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'PICU Primer I' - dara


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
kevin m creamer m d pediatric critical care walter reed amc
Kevin M. Creamer M.D.

Pediatric Critical Care

Walter Reed AMC

PICU Primer I

the primer outline
Physiology

Hypoxia / Hypoxemia

ABG’s and Acidosis

Sodium and H2O metabolism

Hemodynamics and Cardiopulmonary interactions

ICU Care & Common Problems

Head trauma

Toxicology

Postoperative issues

Mechanical Ventilation

The Primer Outline
slide3

Can you have hypoxia without hypoxemia?

  • Can you have hypoxemia without hypoxia?
oxygen and hypoxemia
Oxygen and Hypoxemia
  • Define
    • Hypoxemia
    • Hypoxia
hypoxemia
Hypoxemia
  • Ventilation/Perfusion mismatch
  • Hypoventilation
  • Shunt
  • Diffusion
  • Decreased Ambient O2
oxyhemoglobin curve
Oxyhemoglobin Curve

>> low pH, high Temp

shunt dead space spectrum
Shunt / Dead Space Spectrum

V/Q = 0 V/Q = infinity

No amount of  O2  difference

will fixbetween EtCO2 and PaCO2

ventilation perfusion mismatch
Ventilation / Perfusion mismatch
  • Blood
  • Pus
  • Air
  • Water
  • Atalectasis
  • Quantitate using A – a Gradient
a a gradient
A – a Gradient

(Pb-PH2O) x FIO2 - (PCO2/.8) - PaO2

  • Other useful equations
    • Dead Space = 1 - (EtCO2/PaCO2)
    • OI = (Paw x FIO2 x 100)/ PaO2
      • Positive vs. negative pressure
cause for desaturations
Cause for desaturations
  • Anesthesia – hypoventilation
  • Atalectasis – V/Q mismatch
  • Edema - V/Q mismatch
  • Asthma– dead space/ V/Q mismatch
  • Dysfunctional Hemoglobin
  • You may need a CXR and or ABG in addition to H+P to answer the question
slide11

Non respiratory Physiologic causes of a low PaO2

Causes

Effect on P(A­a)O2

  • Nonrespiratory
    • Right­to­left intracardiac shuntDecreased PIO2Low barometric pressureLow FIO2Decreased R valueLow mixed venous oxygen content*
  • Artifact
    • Very high white blood cell countPatient hyperthermia

Increased

Normal Normal Increased

Increased

Increased

*Only in presence of increased venous admixture

hypoxia
Hypoxia
  • Hypoxic - ex. pulmonary disease
  • Anemic – ex. low CaO2 , CO poisoning
  • Distributive - ex. sepsis, emboli
  • Histotoxic – ex. cyanide
oxygen debt oxygen deficit
Oxygen Debt/ Oxygen Deficit

Death>?

MODS >

Inadequate Resuscitation

oxygen content
Oxygen Content
  • Which has the biggest impact on O2 delivery to the tissues?
    • Hemoglobin, Sat, Cardiac Output, or PaO2
  • Which patient has more oxygen in the blood?
    • Patient A, PaO2 89, Sat% 97%, Hg 9.8
    • Patient B, PaO2 60, Sat% 85%, Hg 13.1
slide15

V

A

Hb 15

20

//

15

O2 content cc/dl

Hb 10

//

10

//

Hb 7.5

Hb 0

//

PO2 25 50 75 100 150 600

Sat% 50 75 90 99 100

slide16

Preload

HR

CO

Contractility

SV

DO2

Afterload

Hg

CaO2

PaO2

Sat %

normal values
“Normal” Values
  • CaO2 = (Hg X 1.34 X Sat%) + (PaO2 X 0.003)
    • 17-20cc O2 /dL
  • DO2 = CI X CaO2
    • 400-600 ml X min / M2
  • VO2 = CI X avDo2
    • 140-160 ml X min / M2

Arterial sat 100%

minus

Consumption

= Venous sat 75-80%

oxygen rules of thumb
Oxygen Rules of Thumb
  • Give enough
    • high flow non-rebreather if needed
  • Look for a reason for low Saturations
    • Postop Posterior Spinal Fusion Pt with Sats 88%
  • Don’t be fooled by a little
    • 5 kg baby , RR 40, I:E 1:2, on 2L NC
    • What’s the FiO2?
questions
Questions?
  • NEXT UP
    • ABG’s

and acidosis

acidosis
Acidosis
  • Respiratory vs. Metabolic?
    • Anion gap or not?
  • Acute vs. Chronic?
  • Primary or Secondary?
  • Rule
    • every 10 torr change in PCO2 should result in 0.08 change in pH
    • Every HCO3 drop you should see 1:1 increase in base excess
abg quiz
ABG quiz

1. 1° Respiratory Alkalosis

2. 1° Respiratory and 1° metabolic acidosis

3. 1° Resp acidosis and 2° Metabolic alkalosis

4. 1° Metabolic acidosis and 2° Resp alkalosis

abg quiz22
ABG quiz

1. Crying healthy infant

2. Former preemie with bad BPD

3. Salicylate toxicity

4. Postop spinal fusion patient

5. Moderate Asthma attack on O2

6. DKA

acidosis anion gap
Acidosis - Anion Gap?
  • Pay attention to the frequently overlooked HCO3 on the Chem-7
    • It’s measured not calculated
  • Does the Chloride rise as the HCO3 drops?
acidosis osmole gap
Acidosis - Osmole Gap ?
  • IF AG is + then calculate the osmole gap
    • Difference between measured and calculated OSMs
    • Osm = 2(Na+) + BUN/2.8 +Glu/18
anion gap vs non anion gap
Methanol

Uremia

DKA

Paraldehyde

Iron/INH/inhale CO

Lactic Acid

Ethanol/Ethylene Glycol

Salicylates

GI HCO3 losses

Renal tubular acidosis

Carbonic Anhydrase inhibition

TPN?

Hypoaldosteronism

Anion Gap vs. Non Anion Gap
slide26

Potassium?

OSM Gap?

acidosis treatment
Acidosis treatment
  • Correct underlying problem
    • restore perfusion !!!
  • NaHCO3 usually not necessary
    • Paradoxical CNS acidosis
    • Left shift of oxyhemoglobin curve
  • Think about funky metabolic disorders if the story doesn’t fit
funky acidosis workup
Funky Acidosis Workup
  • First 1-2 hours
    • ABG
    • Chem 10
    • Lactate
    • Ammonia
    • Ketones
    • Urinalysis
    • consider CBC and LFTs’
questions29
Questions?
  • NEXT UP
    • Sodium and water metabolism
  • “There is no such thing as free water, sooner or later you have to pay for it”
sodium and water h p
Sodium and Water H+P
  • HX- intake, output of water and salt
    • Ex. (V/D) , boiled milk or home-made solutions
  • Intravascular Volume (Hi, Low, Nl)
  • Urine volume and concentration
  • Renal Fxn
    • BUN, Cr, K+
    • FeNa+ = (UNa+/PNa+)/(Ucr/PCr)
      • <1% Low effective ECF
hypernatremia
Hypernatremia

Common in under watered ICU patients

hypernatremia other
DI

Central - responds to ADH

look for a CNS lesion

Nephrogenic - doesn’t respond to ADH

Don’t forget

Mineralocorticoid Excess

Renal d/o with High PRA

Hypernatremia - Other
treatment
Goal of any hyperosmolar state correction is to fix problem while avoiding cerebral edema

Pesky idiogenic osmoles

 correct over 48 hours

Hypertonic state may mask symptoms

Correct both Na+ and H2O deficits

Treatment
treatment34
Correct at rate 0.5-.75 mEq/L/hr

Check lytes q4-6°

Watch for Hypogylcemia, Hypocalcemia

Assume all losses are 140 meq/L Na+

Treatment

If Na+ < 160 Fluid = 1/2 NS

If Na+ > 160Fluid = NS

hypernatremia example
10 d.o. 3.3 kg patient presents with Na+ 172, Birth wt 3.9 Kg

assume 600 cc lost is all 140 meq/L Na+

add daily Na+ and H2O X 2

calculations yield 1/2 NS at 28cc/hr

*remember rule and use NS

USE NS and make the patient NPO for at least the first 12 hours

Hypernatremia Example
hyponatremia
Hyponatremia
  • Pseudohyponatremia? i.e. DKA
  • Volume status?
    • High - CHF, Renal or Liver failure, hypoalbuminemia
    • Normal - excess free H2O intake, or SIADH, hypothyroidism
    • Low - GI, Skin,CSF or tissue losses, diuretics, CSW, adrenal insufficiency
hyponatremia38
Hyponatremia
  • Checking urine sodium is invaluable
  • Remember iatrogenic losses
    • Drains
      • Lumbar, or JP, etc
    • Lasix
      • hyponatremic, hypokalemic, metabolic alkalosis
      • fix by replacing Cl- , not Na+
      • give KCL
treatment39
Treatment
  • One goal of hyponatremia correction is to avoid Central Pontine Myelinolysis
  • Correct both Na+ and H2O deficits
  • Correct at rate 0.5 mEq/L/hr
  • Treat Shock with NS then fix other deficits more slowly
special situations
Special Situations
  • SIADH
    • Restrict free H2O
      • 3/4 maintenance NS
    • 3% Saline only for seizures
      • push 2-4 ml/kg over 5 -10 minutes until seizure stops
    • Lasix isn’t going to work
  • CSW
    • Replace ongoing Na+ and H2O losses with combination of 3% and NS
questions41
Questions?
  • NEXT UP
    • Hemodynamics and Cardiopulmonary interactions
  • Pop quiz
    • What are the five determinants of Cardiac output??
hemodynamic determinants
Hemodynamic Determinants
  • CO = HR X SV
    • Preload -Volume
    • Afterload -Resistance to LV emptying
    • Contractility -Squeeze
    • Heart Rate - rate =  SV
    • Rhythm -Atrial kick 10% CO
  • Ohm’s Law(V= I X R) or BP = CO X SVR
cardiac output i
Cardiac output I
  • Pulse quality
  • Central vs. Peripheral pulses
  • Differential Temperatures
  • Capillary refill time (CRT)
  • Organ Perfusion
      • CNS - AVPU?
      • Renal - UOP
        • only organ with easily measured output
  • Acidosis?
hemodynamic assessment
Hemodynamic Assessment
  • Stroke volume - pulse quality
  • Preload - Liver size, CXR - heart size
  • SVR - CRT, Pulse pressure, differential temperatures
altered hemodynamics
Altered Hemodynamics
  • Common features
    • Elevated HR - attempt to  CO
    • Elevated RR - beware Resp. alkalosis
    • Decreased pulses -  CO
    • Depressed LOC -  CO
    • Acidosis -  CO
    • Falling UOP -  CO
treatment priorities
Treatment priorities

Preload

Contractility

Afterload

cardiopulmonary interactions
Cardiopulmonary Interactions
  • Heart and Lungs intimately linked especially during critical illness
    • Ex. Valsalva can cause  intrathoracic pressure which results in  in CO via  venous return
    • RV filling inversely proportional to Thoracic pressure
  • Spectrum
    • Pulsus paradoxicus PEA 2° Tension pneumo

Too much -

Too much +

cardiopulmonary interactions50
Cardiopulmonary Interactions
  • Influence of negative pressure ventilation on healthy hearts is negligible
  • Normally systemic venous return is the main determinant of CO
  • Lung volume or (stretch) can PVR

Lung volume

PVR

FRC

cardiopulmonary interactions53
Cardiopulmonary Interactions
  • 4yo with febrile pneumonia, pleural effusions, poor PO intake and decreased UOP needs endotracheal intubation for respiratory failure
    • What is going to happen when you intubate?
  • Be wary of over stretch in infants
    • Hyperinflation >>  vagal tone >> bradycardia and vasodilation
the end
The End

Mind what you have learned. Save you it can.