1

Shock

Zeng xuan Hu

OCT17

Objective

Concept

Categories

Principles of management

2

Definition

Inadequate tissue perfusion to maintain normal

cellular function

Not all hypotensive patients are in shock

Not all patients in shock are hypotensive

young patient, compensated

3

Definition

Inadequate delivery of O2 (DO2)

Inability to utilize deliered O2

4

Definition

5

Inadequate tissue perfusion-assessment

Mental status change

Vital sign changes(hypotensive)

Oliguria

Lactate

Base deficit

Cr transaminase abnormaity

Underlying disease-NF

Compensatory machenism

-Vasoconstriction, tachy

6

Lactate

Insufficient O2→ pyruvate →lactate

dehydrogenase →lactate dehydrogenase

→lactate → liver(50%), kidney(30%)

The admission level, highest level, time

interval to normalize lactate are important

prognostic indicators for survival.

7

Base deficit

The amount of base in mmoles needed to

titrate 1 L of whole blood to a pH of 7.40

Mild (3 to 5 mmol/L), moderate (6 to 14

mmol/L), severe (15 mmol/L)

Worsen base deficit associated higher

mortality

Caveat: administration of bicarbonate,

hypothermia, hypocapnia

Hypovolemic

Shock

Distributive Shock

•Anaphylactic

•Septic

•Neurogenic

•Adrenal Insufficiency

Cardiogenic Shock

Myopathic,arrhyth

mic,mechanical

Obstructive Shock

Cardiac Tamponade

Tension Pneumothorax

Massive PE

Classification of shock

13

Hypovolemic

Distributive

Obstructive

Cardiogenic

Principle of management

ABC

Restore tissue perfusion

Underlying disease

Monitor

Supportive care

14

Management

Vasopressor/inotrop

16

Case Study Mr. MS

70 male with PHx of CAD

12 hour post MIS splenectomy in PAR

Called for low BP

What’s your approach?

Mr. MS

A intubated SaO2 97% on Fi02 of 50%

B

C BP 80/60, HR 110, Temp 37.2, JVP flat

Right IJ in place

Combative and confused

Cool, mottled extremities

Distended abdomen

U/O borderline received 3 L NS bolus

Mr. MS

Findings suggest inadequate tissue

perfusion?

What type of shock do this pt likely have?

differentials?

-hypovolemic,obstructive, cardiogenic,

distributive

Next ?

19

Mr. MS

Resucitation

WBC 24, Hb 65 Pl 243 coag N trop 0.5

Lactate 4.2

ABG mild met acidosis

CXR bibasilar atelectasis

ECG sinus tachycardia,

Next ?

20

Mr. MS

Bood transfusion started. Taken

immediately OR where bleeding identified

from a short gastric artery. Ligated. 1 L

blood evacuated.

Given 6U pRBC, 4U FFP and 5U Plts intra-

op

Brought to PAR and remains intubated

Hypovolemic shock

Mr. MS( cont’..

On POD 2, complains of substernal chest

pain and SOB. BP falls to 90/60mmHg with

HR 120. Neck veins are distended.

Most likely cause?

23

Acute Respiratory Failure

Zengxuan Hu

OCT17

Definition

Defect in one or both gas exchange functions:

oxygenation and carbon dioxide elimination

PaO2<60mmHg or PaCO2>45mmHg

Derangements in ABGs

Types I, Hypoxemic II, hypercapnic III, Perioperative I V, Shock

Mechanism V/ Q mismatch Alveolar ventilation Atelectasis Hypoperfusion

Etiology Airspace flooding 1. CNS drive

2. N-M coupling

FRC 1. Cardiogenic

2.

hypovolemic

3. Septic

Clinical Description 1. ARDS

2. Alveolar

hemorrhage

1. Overdose/CNS

injury

2. Myasthenia

gravis,

upper

abdominal

incision,

anesthesia

1. Myocardial

infarct

2.

endotoxemia,

bacteremia

Mechanism

●Hypoventilation

●V/Q mismatch

●Shunt

●Diffusion

abnormality

Hypoventilation Won’t breathe –resp drive

Brainstem stroke

Sedatives

Can’t breathe

NM system

Lung/airway

Chest wall/pleura

↑PaCO2 and ↓PaO2

Alveolar –arterial PO2

gradient is normal

V/Q mismatch Capillary flow excessive relative to

vent

V/Q ratio < 1

Small airway occlusion-asthma

Alveoli-collapse,fluid, excessive

capillary blood flow

Admin. of 100% O2 eliminate

hypoxemia

Shunt The deoxygenated blood

bypasses the alveoli and mixes with oxygenated blood → hypoxemia

Persistent of hypoxemia despite 100% O2 inhalation

Hypercapnia occur when shunt is excessive > 50%

Causes of Shunt

Intracardiac

Right to left shunt

Fallot’s tetralogy

Eisenmenger’s

syndrome

Pulmonary

A/V malformation

Pneumonia

Atelectasis/collapse

Pulmonary hemorrhage

Pulmonary contusion

Diffusion Abnormality

Abnormality of the

alveolar membrane

↓ the number of the

alveoli

ARDS

Fibrotic lung disease

Presentations of hypoxia

Respiratory tachypnea, dyspnea

CNS effects

Impaired judgment and cognitive function

Depressed brainstem function-consciousness

Cardiovascular effects Arrhythmia

Myocardial depression

Hypotension, Shock

Presentations of hypercapnia

CNS-mental status change Anxiety, irritability

Confusion

Lethargy, Stupor, coma

Respiratory – shallow breathing

Cardiovascular effects

Hypotension

Ventricular irritability

Diagnosis of RF

-Investigations ABG

CBC, Hb

Anemia → tissue hypoxemia

Polycythemia → chronic RF

Urea, Creatinine

Electrolytes (K, Mg, Ph) → Aggravate RF

↑ Troponin → MI

TSH → Hypothyroidism

Diagnosis of RF

Investigations Chest x ray → Pulmonary edema

→ ARDS

Echocardiography → Cardiogenic

→ ARDS

→ Rt ventricular

hypertrophy in CRF

■ PFT- (FEV1/ FVC ratio)

Decrease → Airflow obstruction

Increase → Restrictive lung disease

Investigations

ECG → cardiac cause of RF

→ Arrhythmia due to hypoxemia & severe acidosis

■ Right heart catheterization

●Pulmonary capillary wedge pressure (PCWP)

● Normal → ARDS (<18 mmHg)

● Increased → Cardiogenic pulmonary edema

Hypoxemic Respiratory Failure

Is PaCO2 increased?

Hypoventilation (PAO2 - PaO2)?

Hypoventilation alone

Respiratory drive

Neuromuscular dz

Hypovent plus another mechanism

Shunt

Inspired PO2

High altitude

FIO2

(PAO2 - PaO2) No

NoYes

Is low PO2 correctable with O2?

V/Q mismatch

No Yes

Yes

Hypercapnic Respiratory Failure

(PAO2 - PaO2)

Alveolar HypoventilationV/Q abnormality

PI max

increasednormal

Nl VCO2

PaCO2 >45mmHg

Not compensation for metabolic alkalosis

Central

Hypoventilation

Neuromuscular

Disorder

VCO2

V/Q

Abnormality

Hypermetabolism

Overfeeding

Management

A B C, identify reversible causes

Endotracheal intubation:

Indications

Severe Hypoxemia

Altered mental status

Severe acidosis

Mechanical ventilation Increase PaO2

Lower PaCO2

Rest respiratory ms (respiratory ms fatigue)

Noninvasive Ventilatory support

(IPPV)

Mild to moderate RF

Intact airway,

Alert, normal airway protective reflexes

Nasal or full face mask, BPAP,CPAP

Improve oxygenation,

Reduce work of breathing

Increase cardiac output

Treating Underlying Disease Antibiotics

Pneumonia

Infection

Bronchodilators (COPD)

Salbutamol

reduce bronchospasm

airway resistance

Anticholinergics (COPD)

Ibratropium bromide

inhibit vagal tone

relax smooth ms

Hemodynamic Support Fluids and electrolytes

Maintain fluid balance and avoid fluid overload

Reduction of O2 requirements

Vasopressor, inotropes

The maintenance of cardiac output is crucial for O2 delivery

Diuretics (pulmonary edema)

Frusemide, Metalozone

44

Recruitment maneuvers

Prone

Inhaled nitric oxide

High frequency oscillation

Ventilation strategy

Case study

A 58 M with no known medical histoy admitted for gallstone pancreatitis.

Receives supportive care.

POA 2 getting worse.SOB. Tachypneic 35/min. Shallow breathing. Using accessory muscles. On 70 % O2 with mask. Anxious.

BP 110/60, HR 90, Temp 37.5, GCS 15

ABG PH 7.34, Po2 40, Pco2 40,

Diminished breath sounds bilaterally with scattered rhonchi

CXR: bilateral nonsegmental infiltrates. no effusion or PTX.

What findings suggest RF ?

What form of RF?

Does he require intubation?

CXR-bilateral infiltration

46

Case study

Diagnosis – ARF type 1

ARDS/Acute lung injury

DD: Aspiration, pnuemonia, PE,

cardiogenic pulmonary edema, lung

contusion(trauma)

Intubation:severe hypoxemia, tachypneic-

impending respiratory arrest, underlying

disease process not clear.

Case study

57 F with Myasthenia Gravis x 1 yr on MESTINO(pyridostigmine) 40mg daily

Depression with borderline personality feature.

Presents to ER with 2 week’s general weakness, mild SOB x 2 days.

In no cute distress. Vitals N. SaO2 95% with 4 L NP

VC x 3 showed 800ml.

ABG 7.35/48/31. Po2 73. CXR possible right side pneumonia.

What form of RF?

Management ?