MECHANICAL VENTILATION & NON-INVASIVE POSITIVE PRESSURE VENTILATION

Question 1

MECHANICAL VENTILATION: GENERAL

Answer 1

Effects of PPV on right vs. left cardiac dynamics:

Worsens Right-Side Dynamice: Decreases RV Preload, Increases RV Afterload

Improves Left-Side Dynamics: Decreases LV Preload, Decreases LV Afterload

2 effects of PEEP on cardiopulmonary physiology:
Higher PEEP improves oxygenation and decreases work when above the alveolar closing capacity

Higher PEEP decreases preload

Variables affecting Minute Ventilation:
Tidal Volule (Vt)
Respiratory Rate (RR)

Variables affecting oxygenation:
Fraction of Inspires 02 (Fi02)
PEEP

Question 2

MECHANICAL VENTILATION: MANAGEMENT

Answer 2

Lung Protective Settings: Vt, RR, Fi02, PEEP, IFR
Vt: 6 cc / kg
RR: 16
Fi02: 100, titrate down below 60
PEEP: 5
IFR: 60

Obstructive Settings: Vt, RR, Fi02, PEEP, IFR
Vt: 6-8 cc / kg
RR: 10
Fi02: 100, titrate down below 60
PEEP: 0-5
IFR: 60

Plateau Pressure Target and strategy to decrease:
If PP > 30, decreased VTE by 1 ml/kg

COMPLICATIONS
Check the patient
Check the vitals
Check the vent

Question 2

DDx: MECHANICAL VENTILATION AND HYPOTENSION

Answer 2

DDx for SHOCK

Vent Specific:
Tension PTX
Auto-PEEP / Dynamic Hyperinflation
Relative Dehydration
Sedation Medications / Post-intubation meds

Question 3

NON-INVASIVE POSITIVE PRESSURE VENTILATION: GENERAL

Answer 3

Indications:
Rapidly reversible cause of respiratory failure with goal of resolution in 6-12 hrs

Conditions with best evidence for usage:
COPD
Cardiogenic Pulmonary Edema
OSA

Criteria
Cooperative
Mod-severe dysnpnea
Tachypnea (>24 breaths / min)
Increased WOB
Hypercapnic Respiratory Acidosis (pH 7.0 - 7.35)
Hypoxemia (PA02/Fi02 < 200mmHg)

Absolute C/i
GCS < 8
Resp / Card arrest
Condition requiring urgent intubation

Relative C/i
Impaired LOC
Hemodynamic Instability
Impaired cough / swallow
Copious secretions
GI bleed with significant emesis

Question 4

BiPAP

Answer 4

BiPAP
Indications:
MC NIPPV in ICU
COPD
Cardiogenic pulmonary edema

Mechanism:
Delivers EPAP (Expiratory Positive Airway Pressure; essentially CPAP) and IPAP (Inspiratory Positive Airway Pressure) synchyronyzed respiratory cycle

EPAP Mechanism / Benefits: Improves oxygenation by provides PEEP -> preventing collapse of small airways + recruits alveoli -> Increase SA and gas exchange

IPAP Mechanism / Benefits: Pressure support on top of PEEP -> reduces respiratory effort, increases tidal volume, improves ventilation

Starting / Titrating:
Start BiPAP at 15/8-10

THEN

Titrate to 20/8-10

Recheck ABG in 1-2 hrs Should see results in 2 hrs

Question 5

CPAP

Answer 5

CPAP
Indications:
Hypoxemic Respiratory Failure

Hypercarbic Respiratory Failure

Mixed Respiratory Failure

Mechanism:
Continuous positive airway pressure delivered throughout respiratory cycle

Patient breaths spontaneously from elevated baseline pressure selivered throughout respiratory cycle

Improves oxygenation by keeping airways open and recruited

PEEP: 5 -10 cm H20

Question 6

AIRVO

Answer 6

4-6 cm PEEP
Hypoxemic Respiratory Failure