Acute Respiratory
Failure and Asthma
Anthony Saleh, MD, FCCP
March 18th, 2011
Disclosures
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No financial disclosures
Avid New York Yankee fan
Michael Jordan admirer
Favorite movie: “Godfather 1”
Major supporter of respiratory
therapists
Outline
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Scope of the problem
Pathophysiology
Management
Invasive/ Non invasive
Specific Ventilatory Strategies
Asthma: Definition
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A chronic inflammatory disorder of the
airways in which many cells and cellular
elements play a role
Susceptible patients develop recurrent
episodes of wheezing, chest tightness, and
coughing, especially at night or in the early
morning
These episodes are associated with
widespread but variable airflow obstruction,
that is often reversible
Prevalence
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Increasing worldwide over the past few
decades
In the United States approximately 16.1
million adults and 6.8 million children have a
diagnosis of asthma
Overall prevalence about 8 %
Fatalities slowly declining, but still excessive
Multiple etiologies for poor outcome
Asthma Fatalities (cont)
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Peaked in 2003
Higher death rates in: Older patients
(greater than 65), females, Puerto
Ricans, non Hispanic blacks
Some proposed mechanisms: Inner
city lower socioeconomic class
Lack of education
Health care disparities
Pathophysiology
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A complex inflammatory disease of the
airways
Inflammation is the hallmark with
ensuing complicated cascades
A variety of pathways are intertwined
Treatment focuses on multiple
different sites of inflammatory activity
Management
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Acute, severe asthma remains a very
difficult issue
Patients typically have persistent
reductions in peak expiratory flow
rates of less than 40% predicted
May have progressive hypercarbia,
altered sensorium, and a marked
increase in work of breathing
Management (cont)
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Pharmacologic interventions:
Frequent, aggressive bronchodilators
Systemic corticosteroids mandated
Oxygen therapy to prevent
desaturations
+/- intravenous magnesium sulfate
Yankee Trivia
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What is Mariano Rivera’s post season
ERA?
Answer
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0.71 (an all time low)
Godfather Trivia
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How many shots were fired at Don
Corleone (and how many hit him??)
Answer
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9 fired
5 successful (but he survived)
Respiratory Therapy
Trivia
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How can you get a patient on VDR
ventilation?
Answer
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Make Felix (the “Don of VDR”) Khusid
an offer he can’t refuse!!
Non Invasive Ventilation
in Asthma
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Paucity of studies to support it’s use
Advantages seen in other entities
(COPD, pulmonary edema) not
matched in well controlled studies
Theoretical improvement yet to be
proven in well designed trials
NIPPV in Asthma (cont)
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1st study: Soroksky A. Stav D. Shpirer
I. Chest 2003; 123: 1018-1025
Randomized double blind, placebo
controlled trial conducted in the
emergency department of an Isreali
hospital
NIPPV group: 17 patients
Control group: 16 patients
Soroksky Study (cont)
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4 criteria had to be fulfilled:
FEV1<60% predicted
RR>30 breaths/minute
Asthma of at least 1 years duration
Duration of current attack >7 days
PCO2 not an entry criterion
Soroksky Study (Results)
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NPPV group had a pressure range 8-15 cm
IPAP and up to 5 cm EPAP
Study patients had an improvement in:
More rapid improvement in lung function
Respiratory rate
Decreased hospitalizations
Small trial---uncertain clinical significance
NIPPV in Asthma
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Next study: Murase, et al. Respirology 2010;
15: 714-720
Retrospective cohort study
Rate of endotracheal intubation (ETI) lower
in the NIV group
This study had patients with somewhat
more severe asthma (based on ABG
analysis)
Major limitations with study design
NIPPV in Asthma
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3rd study: Gupta, et al. Respiratory
Care, May 2010, Vol 55, No 5
Prospective, randomized controlled
trial
1st study performed in respiratory care
unit (as opposed to the emergency
department)
NIPPV in Asthma (cont)
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NIV similar in efficacy to standard therapy in
improving respiratory rate, FEV1, ph,
PaO2/FiO2, and PaCO2
NIV was associated with a trend of
improved lung function in a larger number
of patients, shorter ICU and hospital stays,
a trend toward quicker clinical improvement,
and less need for inhaled bronchodilators
NIPPV in Asthma
(Summary)
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Theoretically advantageous
Excellent clinical utility in other conditions
(COPD, Pulmonary edema) has not been
matched in asthma
While a few studies have shown some
benefit, larger more controlled studies are
required
Easy availability of NIPPV may lead to
overuse
NIPPV in Asthma (cont)
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It appears reasonable to start NIPPV if
a patient has no contraindications to
it’s use
Be cautious as to not overuse it
If intubation and mechanical
ventilation required, do not delay it
Who is the greatest post
season pitcher of all time?
Answer
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Mariano Rivera
Invasive Ventilatory
Management
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Fortunately, a minority of patients with
asthma require mechanical ventilatory
assistance
Frought with potential complications
Patients are frequently anxious and
require deep sedation and at times
paralysis
Invasive Ventilatory
Support (cont)
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Obstruction in asthma is different from
the obstruction in COPD
Bronchospasm, edema, and increased
secretions
Obstruction is fixed in asthma, making
inspiration as difficult as exhalation
Invasive Management
(cont)
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Major concern: Development of
intrinsic PEEP
Increased work of breathing also very
worrisome
Once instituted, must pay very close
attention to specific ventilator details
Invasive Management
(Initial Ventilator Settings)
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Mode: Volume assist/control
Inspiratory time: 1-1.5 seconds to
allow gas to move past obstructions
Flow waveforms: decelerating
Tidal volume: 5-8 cc/kg IBW
Peak flow: Appropriate to allow tidal
volume delivery in allotted time
Initial Ventilator Settings
(cont)
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PEEP: 0-5 cm H2O
Plateau pressure: less than 30 cm H2O
Rate: 8-16 breaths/min, producing
minimum auto-PEEP
Permissive hypercarbia: unavoidable
FIO2: to maintain PaO2>60 mm Hg
Invasive Management
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As with ARDS/ALI, asthmatics are at
risk of developing ventilator induced
lung injury (VILI) because of the
pressure required to ventilate
Although high peak pressures are
seen, plateau pressures usually remain
below 30 cm H2O
Invasive Management
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It is not uncommon to have peak
pressures in excess of 60-70 cm of
H2O
Dramatic drop off in peak/plateau
characteristic
Hypercarbia common and expected in
many instances
Question 1
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A 25 year old asthmatic is intubated for
severe respiratory distress. He is quite
agitated and thrashing about, in spite of
heavy sedation and is out of synch with the
ventilator. He is on a tidal volume of 8cc/kg
and his ABG on 100% FiO2 and PEEP of 5
is: 7.15/75/67/93/26. His plateau pressure is
31 cm H2O. The next best intervention
would be to:
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A: Increase the tidal volume to
10cc/kg
B: Increase the PEEP to 10 cm H2O
C: Start neuromuscular blockade
D: Decrease FiO2 to 80%
Answer
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C: Start neuromuscular blockade
Neuromuscular Blockade
in Asthma
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British Journal of Hospital Medicine,
January 2009, Vol 70, No 1
These agents help prevent respiratory
dysynchrony
Help lower peak pressures
Allow longer expiratory times to
reduce dynamic hyperinflation
Neuromuscular Blockade
(cont)
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Many of these patients are young, males,
and can be difficult to sedate
Unfortunately, these agents have a variety
of adverse, potentially serious side effects
Must weigh the potential risks/benefits of
using these agents
If these agents are to be used, they should
be stopped as soon as possible
Neuromuscular Blockade
(cont)
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Neuromuscular blocking agents alone
can be associated with prolonged
muscle weakness
Combination of corticosteroids and
aminosteroid neuromuscular blocking
agents (such as vecuronium) may be
associated with an increased risk of
neuromuscular weakness
Summary of
Neuromuscular Blockade
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Asthma represents a group of patients
who may particularly benefit from this
modality
Use with caution and be prepared to
stop as quickly as possible
Be aware of potential complications
Avoid aminosteroid blocking agents
Yankee Trivia
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How many innings did Mariano Rivera
pitch in game seven of the 2003 ALCS
against the rival Boston Red Sox?
Answer
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3 shut out innings in a dramatic 6-5
Yankee win (Aaron Boone’s walk off
home run)
How many NBA
Championships are here?
Answer
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17
Bill Russell:11
Michael Jordan:6
Ventilatory Management
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Intubation and Mechanical Ventilation of the
Asthmatic Patient in Acute Respiratory
Failure
Brenner B, Cobridge T, and Kazzi A.
Proceedings of the American Thoracic
Society. Volume 6 pp 371-379, 2009
Reviewed evidence based data regarding
intubation and mechanical ventilation of
acute severe asthma in emergency
departments
Invasive Management
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7 Key areas addressed
Prevention of intubation
Criteria for intubation
Intubation technique
Ventilator settings
Immediate post intubation care
Medical management in the ventilated
patient
Prevention and treatment of complications
Prevention of Intubation
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Best intubation is NO intubation
Mortality 10-20% in patients requiring
intubation
Aggressive medical therapy, ?? Early
NIPPV
Criteria for Intubation
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4 Indications for intubation:
Cardiac arrest
Respiratory arrest or severe bradypnea
Physical exhaustion
Altered sensorium, such as lethargy or
agitation
Good clinical judgement always
supercedes numbers
Intubation Technique
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Some advocate awake intubation
Main method used is rapid sequence
intubation with ketamine and
succinylcholine
Propofol preferred over ketamine in
hypertensive patients
Avoid succinylcholine in patients with
hyperkalemia
Invasive Management
(Initial Ventilator Settings)
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Mode: Volume assist/control
Inspiratory time: 1-1.5 seconds to
allow gas to move past obstructions
Flow waveforms: decelerating
Tidal volume: 5-8 cc/kg IBW
Peak flow: Appropriate to allow tidal
volume delivery in allotted time
Initial Ventilator Settings
(cont)
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PEEP: 0-5 cm H2O
Plateau pressure: less than 30 cm H2O
Rate: 8-16 breaths/min, producing
minimum auto-PEEP
Permissive hypercarbia: unavoidable
FIO2: to maintain PaO2>60 mm Hg
Immediate Post
Intubation Management
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Adequate sedation mandated
??? Heliox
Selected cases: Paralytic agents
Avoid excessive propofol (propofol
infusion syndrome)
When lung mechanics improved,
rapidly wean sedation
Medical Management
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Systemic steroids
Frequent bronchodilators
??? Magnesium sulfate
Prevention and Treatment of
Complications
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Intubation-induced bronchospasm
Well known entity
Pretreatment with bronchodilators
helps prevent this complication
Hypotension
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Multiple potential etiologies
Most important ones to recognize
immediately are auto-PEEP and
pneumothorax
Fluids bolus immediately
STAT chest x-ray
Increase flow rate to definitively treat
auto-PEEP
Ventilatory Strategies
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If patient failing “ conventional
ventilation” can try newer modalities
VDR: Volumetric Diffusive Respiration
Excellent theoretically for patients with
ARDS or airway issues (including
asthma)
Secretion removal is unprecedented
Question 2
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A 30 year old woman with status
asthmaticus has been endotracheally
intubated and is supported by mechanical
ventilation. She has had a progressive
decline in her BP over the past 30 minutes,
to 80/40 mm Hg, as well as decreasing
oxygen saturation, which is now 91%. Her
heart rate is 126/min. Examination of her
chest reveals hyperinflation and faint breath
sounds, with inspiratory and expiratory
wheezes bilaterally.
Question 2 (cont)
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The breath sounds are more faint than previously
noted, but equal bilaterally. Minimal secretions are
recovered with tracheal suction. She is deeply
sedated with midazolam and fentanyl. Her current
ventilator settings include pressure-targeted assistcontrol ventilation with a set rate of 20, inspiratory
pressure of 25 cm H2O, inspiratory time of 1 sec,
PEEP of 5 cm H2O, and FiO2 of 50%. Her total
respiratory rate is 20/min, and the expired tidal
volumes have decreased from 500 to 350 cc’s, with
no change in ventilator settings.
Question 2 (cont)
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A chest radiograph shows the
endotracheal tube to be in good
position, with bilateral hyperinflation
and clear lung fields. ABG analysis
shows: ph: 7.24/ pCO2: 60 mm Hg/
paO2 70 mm Hg. Among the following
options, the BEST is:
Question 2 (cont)
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A: Deep tracheal suction with saline lavage, and
then increase the inspiratory pressure to 30 cm H20
B: Deep tracheal suction with saline lavage, and
then change to volume-assist control mode with set
tidal volume of 500 cc
C: Briefly disconnect the ETT from the ventilator
tubing and then reduce the set rate to 12/min
D: Briefly disconnect the ETT from the ventilator
tubing and then increase the inspiratory pressure to
30 cm H20
Answer
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C: Briefly disconnect the ETT from the
ventilator tubing and then reduce the
set rate to 12/min
Summary
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Acute respiratory and asthma is a
common scenario
Be aware of best available medical
management
Try to avoid intubation if at all possible
Consider NIPPV if no contraindications
exist
Summary (cont)
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If needed proceed to intubation and
mechanical ventilation
Use guidelines described specifically
for asthma
Be able to rapidly diagnose and treat
complications
Always exercise good clinical
judgement
Final Questions
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What is the name of the drug dealer
who Don Corleone refuses?
Answer
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Virgil “The Turk” Solozzo
Who will win the 2011
World Series?
Answer
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Hopefully--- New York Yankees
Thank you to
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Felix Khusid (the Don of Respiratory
therapists)
All therapists who make their
physicians look better than they really
are!!!