2. Introduction
Shock is a syndrome that results from
inadequate oxygen delivery to meet
metabolic demands
Oxygen delivery (DO2 ) is less than
Oxygen Consumption (< VO2)
Untreated this leads to metabolic
acidosis, organ dysfunction and death
3. Oxygen Delivery
Oxygen delivery = Cardiac Output x Arterial
Oxygen Content
(DO2 = CO x CaO2)
Cardiac Output = Heart Rate x Stroke Volume
(CO = HR x SV)
– SV determined by preload, afterload and contractility
Art Oxygen Content = Oxygen content of the
RBC + the oxygen dissolved in plasma
(CaO2 = Hb X SaO2 X 1.34 + (.003 X PaO2)
4. Figure 1.
FACTORS AFFECTING OXYGEN DELIVERY
Hgb
CaO2
A-a gradient
DPG
Acid-Base Balance
Blockers
Competitors
Temperature
Influenced By
Oxygenation
DO2
Influenced By
Drugs
Conduction System
HR
CO
EDV
SV
CVP
Venous Volume
Venous Tone
Ventricular
Compliance
Influenced By
ESV
Contractility
Influenced By
Afterload
Temperature
Drugs
Metabolic Milieu
Ions
Acid Base
Temperature
Drugs
Toxins
Blockers
Competitors
Autonomic Tone
5. Stages of Shock
Compensated
– Vital organ function maintained, BP
remains normal.
Uncompensated
– Microvascular perfusion becomes
marginal. Organ and cellular function
deteriorate. Hypotension develops.
Irreversible
6. Clinical Presentation
Early diagnosis requires a high
index of suspicion
Diagnosis is made through the
physical examination focused on
tissue perfusion
Abject hypotension is a late and
premorbid sign
8. Initial Evaluation: Directed
History
Past
medical history
– heart disease
– surgeries
– steroid use
– medical problems
Brief history of present illness
– exposures
– onset
10. Differential Diagnosis of Shock
Precise etiologic classification may be
delayed
Immediate treatment is essential
Absolute or relative hypovolemia is
usually present
11. Neonate in Shock:
Include in differential:
Congenital adrenal hyperplasia
Inborn errors of metabolism
Obstructive left sided cardiac lesions:
– Aortic stenosis
– Hypoplastic left heart syndrome
– Coarctation of the aorta
– Interrupted aortic arch
12. Management-General
Goal: increase oxygen delivery and
decrease oxygen demand:
For all children:
○ Oxygen
○ Fluid
○ Temperature control
○ Correct metabolic abnormalities
Depending on suspected cause:
○ Antibiotics
○ Inotropes
○ Mechanical Ventilation
13. Management-General
Airway
If not protected or unable to be maintained,
intubate.
Breathing
Always give 100% oxygen to start
Sat monitor
Circulation
Establish IV access rapidly
CR monitor and frequent BP
15. Management-Volume Expansion
Optimize preload
Normal saline (NS) or lactated ringer’s
(RL)
Except for myocardial failure use 1020ml/kg every 2-10 minutes. Reasses
after every bolus.
At 60ml/kg consider: ongoing losses,
adrenal insufficiency, intestinal
ischemia, obstructive shock. Get CXR.
May need inotropes.
16. Fluid in early septic shock
Carcillo, et al, JAMA, 1991
Retrospective review of 34 pediatric patients with
culture + septic shock, from 1982-1989.
Hypovolemia determined by PCWP, u.o and
hypotension.
Overall, patients received 33 cc/kg at 1 hour and 95
cc/kg at 6 hours.
Three groups:
– 1: received up to 20 cc/kg in 1st 1 hour
– 2: received 20-40 cc/kg in 1st hour
– 3: received greater than 40 cc/kg in 1st hour
No difference in ARDS between the 3 groups
17. Fluid in early septic shock
Carcillo, et al, JAMA, 1991
Group 1 Group 2 Group 3
Hypovolemic at
6 hours
(n = 14)
6
(n = 11)
2
(n = 9)
0
-Deaths
Not hypovolemic
at 6 hours
6
8
2
9
0
9
-Deaths
Total deaths
2
8
5
7
1
1
19. Inotropes and Vasopressors
Lack of history of fluid losses, history of
heart disease, hepatomegaly, rales,
cardiomegaly and failure to improve
perfusion with adequate oxygenation,
ventilation, heart rate, and volume
expansion suggests a cardiogenic or
distributive component.
Consider Appropriate inotropic or
vasopressor support.
20. Case 1
15-year-old previously well boy is freshly from the PICU, POD
#3 from partial small bowel resection after multiple gunshot
wounds to the abdomen. The nurse pages because his HR
has increased in the last hour from 90 to 130, despite pain
score of 1/10 on morphine drip. On exam, he is afebrile, HR is
140, BP 80/50. Cap refill is >3 seconds in his cool extremities
and pulses are 1+.
What is your assessment?
What is the stage of shock?
What is the classification of shock?
What is your initial management?
21. Hypovolemic Shock
Most common form of shock world-wide
Results in decreased circulating blood
volume, decrease in preload,
decreased stroke volume and resultant
decrease in cardiac output.
Etiology: Hemorrhage, renal and/or GI
fluid losses, capillary leak syndromes
22. Hypovolemic Shock
Clinically, history of vomiting/diarrhea or
trauma/blood loss
Signs of dehydration: dry mucous
membranes, absent tears, decreased
skin turgor
Hypotension, tachycardia without signs
of congestive heart failure
23. Hemorrhagic Shock
Most common cause of shock in the
United States (due to trauma)
Patients present with an obvious history
(but in child abuse history may be
misleading)
Site of blood loss obvious or concealed
(liver, spleen, intracranial, GI, long bone
fracture)
Hypotension, tachycardia and pallor
24. Hypovolemic/Hemorrhagic
Shock: Therapy
Always begin with ABCs
Replace circulating blood volume
rapidly: start with crystalloid
Blood products as soon as available for
hemorrhagic shock (Type and Cross
with first blood draw)
Replace ongoing fluid/blood losses &
treat the underlying cause
25. Septic Shock
SIRS/Sepsis/Septic shock
Mediator release:
exogenous & endogenous
Maldistribution
Cardiac
of blood flow
dysfunction
Imbalance of
oxygen
supply and
demand
Alterations in
metabolism
28. Septic Shock
Cold Shock rapidly progresses to mutiorgan
system failure or death if untreated
Multi-Organ System Failure: Coma, ARDS, CHF,
Renal Failure, Ileus or GI hemorrhage, DIC
More organ systems involved, worse the
prognosis
Therapy: ABCs, fluid
Appropriate antibiotics, treatment of underlying
cause
29. Case 2
6-year-old previously well girl is admitted to your ward directly
from clinic with fever, bloody diarrhea x 1 day. She’s had no
urine x 24 hrs and is becoming harder to awaken. On exam,
her HR is 150, BP 72/30, temp 103. She’s sleepy but
arousable. She’s flushed with capillary refill <1 second.
What is your assessment?
What is the stage of shock?
What is the classification of shock?
What is your differential for the etiology?
What is your initial management? If a higher level of care is needed,
how would you obtain it?
31. Cardiogenic Shock
Differentiation from other types of
shock:
– History
– Exam:
Enlarged liver
Gallop rhythm
Murmur
Rales
– CXR:
Enlarged heart, pulmonary venous congestion
32. Cardiogenic Shock
Management:
– Improve cardiac output::
Correct dysrhthymias
Optimize preload
Improve contractility
Reduce afterload
– Minimize cardiac work:
Maintain normal temperature
Sedation
Intubation and mechanical ventilation
Correct anemia
33. Case 3
4-month-old boy ex-term, previously well boy presents to ED
with decreased desire to feed x 2 days with 2 times daily
emesis, following what sounds like viral URI. Urine output has
been 3 wet diapers daily. He is afebrile with HR 180; BP has
not been obtained. He has a weak cry, is mottled with 3-second
capillary refill, pulses 1+ in all extremities. Liver is palpable 4 cm
below RCM. S4 is present without murmur.
What is your assessment?
What is the stage of shock?
What is the classification of shock?
What is your differential for the etiology?
What is your initial management?
34. Distributive Shock
Due to an abnormality in vascular tone
leading to peripheral pooling of blood with a
relative hypovolemia.
Etiology
–
–
–
–
Anaphylaxis
Drug toxicity
Neurologic injury
Early sepsis
Management
–
–
Fluid
Treat underlying cause
35. Obstructive Shock
Mechanical obstruction to ventricular
outflow
Etiology: Congenital heart disease,
massive pulmonary embolism, tension
pneumothorax, cardiac tamponade
Inadequate C.O. in the face of adequate
preload and contractility
Treat underlying cause.
36. Dissociative Shock
Inability of Hemoglobin molecule to give up
the oxygen to tissues
Etiology: Carbon Monoxide poisoning,
methemoglobinemia, dyshemoglobinemias
Tissue perfusion is adequate, but oxygen
release to tissue is abnormal
Early recognition and treatment of the
cause is main therapy
37. Hemodynamic Variables in
Different Shock States
Hypovolemic
Cardiogenic
Obstructive
Distributive
Septic:
Early
Septic: Late
CO
↑
↓↓
↓
↑↑
↑↑↑
↓↓
SVR
↑
↑↑↑
↑
↓↓↓
↓↓↓
↑↑
MAP
↔ Or
↔↓Or
↔↓Or
↔↓Or
↔↓Or
↓
↓↓
Wedg
e
↓↓↓
↑↑
↑↑
↔ Or
↓
↓
↑
CVP
↓↓↓
↑↑
↑↑
↔ Or
↓
↓
↑ or
↔
38. Final Thoughts
Recognize compensated shock quickly- have a
high index of suspicion, remember tachycardia is
an early sign. Hypotension is late and ominous.
Gain access quickly- if necessary use an
intraoseous line.
Fluid, fluid, fluid - Administer adequate amounts of
fluid rapidly. Remember ongoing losses.
Correct electrolytes and glucose problems quickly.
If the patient is not responding the way you think
he should, broaden your differential, think about
different types of shock.
39. Take-Home Points
Shock is a progressive process.
Intervene early.
Identifying the stage and classification of
shock is important.
Stage: Compensated, uncompensated, or irreversible?
Classification: Hypovolemic, distributive, cardiogenic, or
obstructive?
Management should be directed at
normalizing tissue perfusion and blood
pressure.
Consider using the consensus-based goal-directed
algorithm for shock management.
Notas del editor
Teachers’ Guide:
(This represents hypovolemic shock.)
Example questions and examples of acceptable answers:
What is your assessment?
15 year-old post-operative patient with sudden tachycardia and borderline low blood pressure with impaired peripheral perfusion. Suggests hypovolemic shock.
2) What stage of shock?
Compensated … for now, given his lack of hypotension by strict definition. Given rapidity of onset, be extremely cautious for rapid decline.
3) What classification of shock? If uncertain, what additional information would you want to obtain to decide?
Hypovolemic shock, likely due to blood loss related to surgery; less likely septic shock (though you would be suspicious of this given the nature of his wounds) due to his physical exam findings.
What is your initial management.
Again, ABCDs, fluid resuscitation with 20 ml/kg crystalloid as needed to restore perfusion and blood pressure. Ensure a type and screen/cross match has been done and order PRBCs to the bedside in the event that bleeding continues. Stat baseline hemoglobin/hematocrit with repeat every 4 hrs until stable.
MAIN TEACHING POINT: Hypovolemic shock is often first manifest by tachycardia and decreased peripheral perfusion. Hypotension is a late finding and indicates uncompensated shock.
Teachers’ Guide:
(This represents distributive (most likely septic) shock.)
Example questions and examples of acceptable answers :
What is your assessment?
6 year-old with altered mental status and oliguria, with hypotension and peripheral vasodilation after 1 day fever, bloody diarrhea. Likely septic shock.
2) What stage of shock?
Uncompensated, given hypotension accompanying altered mental status and oliguria.
3) What classification of shock?
Likely septic shock, given vasodilation in setting of what sounds like infection.
What is your differential for the etiology?
(not exhaustive differential) For fever and bloody diarrhea: Infectious causes -- salmonella, shigella, e-coli-0517, yersenia, c-diff, e. histolitica; Rheumatologic causes: IBD; Food allergies/intolerances less likely.
What is your initial management?
ABCDs, fluid resuscitation with 20 ml/kg crystalloid as needed to restore perfusion and blood pressure. Given the likelihood of septic shock, the goal is to give broad spectrum antibiotics within the first 15-30 minutes. Good antibiotic choices in a critically ill normal host would cover most gram negatives, gram positives (including MRSA) and anaerobes (in this case, since the likely source is intestinal): Ceftriaxone or cefotaxime, plus vancomycin, plus metronidazole is an example of an acceptable combination. If the patient were not clearly septic but if dehydration were more likely responsible for her findings, one should consider that antibiotics increase the likelihood of HUS with e-coli and increase the duration of salmonella carriage.
Regarding escalation of care, this patient, in uncompensated shock, should require at least ICU monitoring. Discuss the protocol in your institution for instituting a higher level of care immediately.
MAIN TEACHING POINT: Distributive shock is often marked by increased peripheral vasodilation. Sepsis is the most common cause of distributive shock; if suspected broad-spectrum antibiotics should be delivered in the first 15-30 minutes.
Teachers’ Guide:
(This represents cardiogenic shock.)
Example questions and examples of acceptable answers:
What is your assessment?
4 mo old with subacute onset of decreased desire to feed, emesis in setting of viral symptoms and possibly decreased urine output. Afebrile on exam with tachycardia and signs of hypoperfusion and liver distension and gallop. Suggests cardiogenic shock.
2) What stage of shock?
Answer is unclear given lack of available BP reading, but exam with impaired perfusion (and weak cry possibly indicating altered mental status) would suggest progression toward uncompensated shock.
3) What classification of shock? If uncertain, what additional information would you want to obtain to decide?
Likely cardiogenic, given decreased desire to feed, emesis, impaired perfusion, distended liver, and S4. Additional information could be gained through CXR looking for cardiac enlargement and pulmonary edema, stat echo, lactate, possibly chemistry looking for acidosis due to hypoperfusion and electrolyte imbalances due to emesis, +/- BNP.
What leads your differential for the etiology?
Given recent viral illness, viral cardiomyopathy possible cause.
What is your initial management?
ABCDs, continuing to monitor blood pressure closely and ensuring sufficient access, 10 ml/kg bolus (repeated with caution and constant monitoring for worsening heart failure, as needed) to restore perfusion if altered mental status or other signs of end organ dysfunction. Stat cardiac echo (or at least bedside ultrasound). Dopamine stat to the bedside. Stat cardiology consultation.
MAIN TEACHING POINT: Cardiogenic shock is marked by decreased peripheral perfusion due to decreased cardiac output. Despite increased preload in cardiogenic and obstructive shocks, fluid boluses may be needed to restore perfusion if signs of end organ dysfunction. Howerver, because patient may worsen with these boluses the volume should be small and re-evaluation should occur after each intervention.
