(How to save a life when I’m alone in the middle of the night)
Nick Mohr, MD
Assistant Professor
Department of Emergency Medicine
Division of Critical Care, Department of Anesthesia
University of Iowa Carver College of Medicine

• To review basic mechanical ventilation theory and terminology
• To define an algorithmic approach to mechanical ventilation in the emergency department
• To explore algorithms for troubleshooting ventilation and oxygenation problems
• To discuss specific clinical scenarios requiring specialized ventilation strategies

• This speaker has no financial relationships to disclose.
• Topics discussed in this lecture are a component of the University of Iowa Visiting Professor Program
Conference Series.
• The content of this lecture was developed following an extensive literature search and contains up-todate, evidence-based information.

Rescue Modes: APRV, HFOV
Ventilation Adjuncts: Proning, Inhaled Vasodilators, Heliox
Advanced Strategies: Triggering, PRVC/VC+
Ventilation Mechanics: Inflection Points, Loops, Synchrony
Basic Mechanical Ventilation
Education
90%

What is the goal of mechanical ventilation?

Definitions
Definitions

• Assist-Control (A/C)
– Volume Control (VC)
– Pressure Control (PC)
– Pressure Regulated Volume Control (PRVC/VC+)
• Synchronized Intermittent Mandatory Ventilation (SIMV)
• Pressure Support Ventilation (PSV)
Definitions

• PEEP
p
PEEP t
Definitions

peak plateau
• PEEP
• Tidal Volume
• FiO
2
• Respiratory Rate
– Set vs. actual
• Peak Pressure
• Plateau Pressure p t
Definitions

Definitions
Respiratory
Rate
“Ventilation”
Tidal Volume
“Lung Protection”
FiO
2
PEEP
“Oxygenation”

Algorithm
Determann RM. et al. Crit Care 2010;14:R1

Algorithm
Mascia L. et al. JAMA 2010;304:2620-7.

Ventilation Algorithm
Courtesy Scott Weingart, MD
Algorithm

1. Select ventilation strategy
Successful Intubation
Lung Protection Strategy Obstructive Lung Disease
Algorithm

1. Select ventilation strategy
Successful Intubation
Lung Protection Strategy Obstructive Lung Disease
Algorithm

2. Calculate ideal tidal volume
IBW male
(kg) = 50 + (2.3 x h
(over 5 ft)
(in))
IBW female
(kg) = 45.5 + (2.3 x h
(over 5 ft)
(in))
Goal volume 6 mL/kg
Algorithm

Image courtesy JustPressPlay ®
Algorithm
Height
5 ft 2 in
5 ft 5 in
5 ft 8 in
5 ft 11 in
6 ft 2 in
6 ft 5 in
6 ft 8 in
Male
350
400
450
500
550
600
650
Female
350
400
450
500
500
550
600

How well do we practice low tidal volume ventilation in the ED?
Algorithm
Fuller BM. et al. Acad Emerg Med 2013;20:659-69.

3. Select respiratory rate
Try to match required minute ventilation
Usually start at 14-18 breaths/minute
Check a blood gas
Algorithm

4. Select oxygenation parameters
Start all ventilated patients at FiO
2
= 100%
Wean aggressively
Algorithm

Algorithm

Algorithm
Pressure

Algorithm
PEEP
Pressure

Algorithm
PEEP
Pressure

Pulmonary artery
AIR
Pulmonary vein
SHUNT
Bendixen HH. et al. N Engl J Med 1963;269:961-6
Algorithm

Algorithm
Slutsky AS. et al. NEJM 2006;354:1839-41

• Decrease shunt
• Prevent atelectasis
• Increase mean airway pressure
FiO
2
30%
40%
40%
50%
50%
60%
70%
70%
70%
80%
90%
90%
90%
100% 18-24
14
14
14
16
18
PEEP
5
5
8
8
10
10
10
12
Brower RG. et al. N Engl J Med 2000;342:1301-8
Algorithm

P
5. Limit plateau pressure peak plateau
P ventilator alveoli
Algorithm

6. Check blood gas, reassess
Check ABG/VBG at 15-30 minutes
Correlate with EtCO
2
Algorithm

Lung Protective Ventilation
Plateau Pressure
≤ 30 cm H
2
0
Algorithm
Tidal volume
6 – 8 mL/kg
Minimize FiO
2
PEEP set to limit atelectasis and shunt
(PEEP table)
Pressure

Goal-Directed Ventilation
MAP ≥ 65
Comfort
Sedation
Pain
Control pH ≥ 7.15
V
FiO
2
T
≤ 60%
< 8 mL/kg p plateau
< 30 pO
2
≥ 60
Algorithm

1. Start with A/C (VC), sedation/pain control
2. Set tidal volume (6 – 8 mL/kg IBW)
3. Adjust respiratory rate for ventilation
4. Set FiO
2 at 100% and wean aggressively
– Titrate PEEP to necessary FiO
2
(table)
5. Check plateau pressure (goal < 30)
6. Check blood gas and titrate
Algorithm

How does ventilation differ in patients with obstructive lung disease?
Algorithm

P
Flow
Disease
Peak pressure rises
“Air trapping”
Flow does not return to zero
Algorithm

Algorithm
Marini. et al. Critical Care Medicine: The Essentials , 1997

Flow
Normal
“Rest”
Algorithm
Abnormal
“No Silence”

Respiratory
Rate
“Ventilation”
Tidal Volume
“Lung Protection”
FiO
2
PEEP
“Oxygenation”
Algorithm

1. Select ventilation strategy
Successful Intubation
Lung Protection Strategy Obstructive Lung Disease
Algorithm

2. Calculate ideal tidal volume
IBW male
(kg) = 50 + (2.3 x h
(over 5 ft)
(in))
IBW female
(kg) = 45.5 + (2.3 x h
(over 5 ft)
(in))
Goal volume 8 mL/kg
Algorithm

3. Select respiratory rate
Try to meet ventilatory demands
Start at 8 breaths per minute
Reassess at bedside – look at flow loop
T HIS IS THE MOST EFFECTIVE WAY TO KILL A SEVERE
ASTHMATIC WITH THE VENTILATOR
Algorithm

4. Select oxygenation parameters
Start all ventilated patients at FiO
2
= 100%
Wean aggressively
These patients probably will not require high
FiO
2 levels
Algorithm

5. Set PEEP
Start low (PEEP 0 okay)
Keep it low
Algorithm

P
6. Limit plateau pressure peak plateau
P ventilator
Recheck frequently alveoli
Algorithm

7. Check blood gas, reassess
Check ABG/VBG at 15-30 minutes
Correlate with EtCO
2 pH ≥ 7.10 – 7.15 is good enough in most circumstances
Algorithm

Goal-Directed Ventilation
MAP ≥ 65
Comfort
Sedation
Pain
Control pH ≥ 7.15
V
FiO
2
T
≤ 60%
< 8 mL/kg p plateau
< 30 pO
2
≥ 60
Algorithm

1. Start with A/C (VC), sedation/pain control (deep)
2. Set tidal volume (8 mL/kg IBW), higher for ventilation
3. Keep respiratory rate low
4. Set FiO
2 at 100% and wean aggressively
– Use PEEP 0 - 5
5. Check plateau pressure (goal < 30), no air trapping
6. Check blood gas and titrate
Algorithm

Troubleshooting the Ventilator
Troubleshooting

Failures of Mechanical Ventilation
Hypoxia Hemodynamic Instability
Troubleshooting

P
E
D islodgement
O
EtCO
2
Direct
Visualization
Fiberoptic
Bronchoscopy
Troubleshooting

P
E
D islodgement
O bstruction
Pass suction catheter
Lavage
Replace ETT
Troubleshooting

D islodgement
O bstruction
P neumothorax
E
Bilateral breath sounds
Tracheal deviation
Ventilator peak pressures
Troubleshooting

D islodgement
O bstruction
P neumothorax
E quipment failure
Bag-valve on
FiO2 100%
Use PEEP valve
Check ventilator
Troubleshooting

D islodgement
O bstruction
P neumothorax
E quipment failure
Troubleshooting

Failures of Mechanical Ventilation
Hypoxia Hemodynamic Instability
Troubleshooting

Post-Intubation New Onset
Induction Tension PTX
Loss of sympathetic tone
Right heart dysfunction
Volume depletion
Image courtesy Department of Environmental
Health, Pitkin County, Colorado
Breath stacking/Air trapping
Excessive
PEEP
Hypoxia/vagal
Troubleshooting

Post-Intubation New Onset
Fluid bolus Disconnect the ventilator
Vasopressor
Look for tension PTX BV slowly, unless intubated for acidemia
Image courtesy Department of Environmental
Health, Pitkin County, Colorado BV slowly, turn down
PEEP
Troubleshooting

Cases
Cases

84 y/o f (height 5’11”) with UTI presents with hypotension (BP70/30), tachycardia
(P135), fever (T39.1 C), and unresponsiveness
You decide to intubate.
Ventilator settings?
Cases

1. Start with A/C (VC), sedation/pain control
2. Set tidal volume (6 – 8 mL/kg IBW)
3. Adjust respiratory rate for ventilation
4. Set FiO
2 at 100% and wean aggressively
– Titrate PEEP to necessary FiO
2
(table)
5. Check plateau pressure (goal < 30)
6. Check blood gas and titrate
Cases

29 y/o m (height 5’11”) with h/o asthma presents by ambulance after waking up unable to breath. He is no longer arousable.
P160 BP180/110 RR52 FiO2 86%
You decide to intubate.
Ventilator settings?
Cases

1. Start with A/C (VC), sedation/pain control (deep)
2. Set tidal volume (8 mL/kg IBW), higher for ventilation
3. Keep respiratory rate low
4. Set FiO
2 at 100% and wean aggressively
– Use PEEP 0 - 5
5. Check plateau pressure (goal < 30), no air trapping
6. Check blood gas and titrate
Cases

68 y/o m with h/o COPD was involved in
MVC and was intubated on arrival. While he is returning from CT 25 minutes later, he becomes hypoxic to 60% and bradycardic.
What is your intervention?
Cases

D islodgement
O bstruction
P neumothorax
E quipment failure
Cases

49 y/o f intubated for severe COPD at OSH is transferred for ICU care. As EMS arrives, they are starting chest compressions.
What is your intervention?
Cases

Post-Intubation New Onset
Fluid bolus Disconnect the ventilator
Vasopressor
Look for tension PTX BV slowly, unless intubated for acidemia
Image courtesy Department of Environmental
Health, Pitkin County, Colorado BV slowly, turn down
PEEP
Cases

• Thou shalt not fear mechanical ventilation. Most problems in the ED can be resolved with sedation, respiratory rate, and FiO
2
• Thou shalt not use injurious ventilatory strategies
(low tidal volume)
• Thou shalt not code an asthmatic on the ventilator
(low respiratory rate/air trapping)
• Maintain an algorithmic approach to critically ill patients, then think about the physiology

Nick Mohr, MD
Assistant Professor
Department of Emergency Medicine
Division of Critical Care, Department of Anesthesia
University of Iowa Carver College of Medicine