Transcript Respiratory Dysfunction - UBC Critical Care Medicine

Respiratory Dysfunction
Naisan Garraway
Najib Ayas
The Case

69 yr old male with a 3-day history of
worsening SOB and increase use of his
puffers. He denies chest pain. He also
describes a productive cough with green
sputum. He has a known history of COPD
and quit smoking 1 month ago but had a 40pack year history. He has had multiple
admissions for COPD exacerbations but
never intubated.
The case

His past history is
significant for Type II
DM diet controlled,
HTN, anterior resection
5 yrs ago for
diverticulitis and a large
incisional hernia, which
he is booked for repair
in 2 months
The case
His meds include: Atrovent 4 puffs QID,
Ventolin 2 puffs QID, Cipro (he bought in
Mexico) prn, ECASA 81 mg, Ramipril 5 mg
OD, Cold-FX (during the winter months)
 He is allergic to Penicillin (anaphylaxis)

The Case

He lives with his wife and has a son in
Medical School in Scotland. He quit
smoking 1 month ago and drinks 1-2 beer a
week.
In the ER
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He was seen by the ER doc and was noted
to be alert, SOB with a RR of 20 but could
speak 3-5 word sentences, audible wheezes
bilaterally, no peripheral edema, unable to
see JVP, no abdominal pain, obvious
reducible incisional hernia. BP 150/90, HR
120, and temp 37.5
In the ER
showed WBC 14.8, Hb 140, Plts 400
normal coags. Lytes were Na 138, K 3.5, Cl
100, CO2 35, Creat 160, and BUN 12.
 An ECG showed sinus tachy with poor R
wave progression in the lateral leads. A
CXR showed hyperinflation with possible
“streaking” in the RLL

CXR
In ER
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An IV was started and he was given nebs of
Atrovent and Ventolin. 100 mg
hydrocortisone was given IV. The CTU Snr
was consulted and said would be right there
but was dealing with a septic patient on the
ward.
Later that day
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2 hours later the patient was assessed by CTU and
was found to be obtunded but would rouse to a
loud voices. His BP was 140/81, HR 130 regular,
RR 10, temp 37.8, and a sat of 88%
An ABG was done stat: 7.15/75/104.8/36.
You get the call just having resuscitated a septic
CTU patient on the ward, to get down to the ER
ASAP
Assessment
As you get there your keen Jr resident has
arrived first and tells you the story.
 1. What is the differential diagnosis?

Gord
Hypercapnic Respiratory Failure
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Chronic obstructive pulmonary disease
 Emphysema
 Chronic bronchitis
Neuromuscular disorders
 Amyotrophic lateral sclerosis
 Muscular dystrophy
 Diaphragm paralysis
 Guillain-Barré syndrome
 Myasthenia gravis
Hypercapnic Respiratory Failure
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Chest wall deformities
 Kyphoscoliosis
 Fibrothorax
 Thoracoplasty
Central respiratory drive depression
 Drugs - Narcotics, benzodiazepines,
barbiturates
 Neurologic disorders - Encephalitis,
brainstem disease, trauma
 Primary alveolar hypoventilation
Obesity hypoventilation syndrome
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MI/CHF
PE
Pulmonary Embolism in Patients with Chronic Obstructive
Pulmonary Disease
Ann Intern Med. 2006;144:390-396.
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
Showed a 25% prevalence of PE in patients with COPD
hospitalized for severe exacerbation of unknown origin.
Clinical factors associated with PE were previous
thromboembolic disease, malignancy, and decrease in
PaCO2 of at least 5 mm Hg
BiPAP

You notice the RT is preparing the BiPAP
ventilator.
2. What is the role of BiPAP in COPD
exacerbation/acute respiratory failure?
Gord
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NIPPV
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Two meta-analysis found that patients
randomized to receive NIPPV had a
statistically significant decrease in the
need for invasive mechanical ventilation
and in the risk of death
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Keenan SP, et al: Effect of noninvasive positive pressure
ventilation on mortality in patients admitted with acute
respiratory failure: a meta-analysis. Crit Care Med 1997.
Thys F, et al: Noninvasive ventilation for acute respiratory
failure: a prospective randomized placebo-controlled trial.
Eur Respir J 2002
NIPPV
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Exacerbations of COPD with rapid
clinical deterioration should be
considered candidates for NIPPV
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International consensus conferences in intensive care
medicine: noninvasive positive pressure ventilation in acute
respiratory failure. Am J Respir Crit Care Med 2001,
163:283–291.
NIPPV
Noninvasive ventilation in acute respiratory failure
Nicholas S. Hill, et al; Crit Care Med 2007 Vol. 35,
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Review of the literature supports that an initial trial
with NIV is not deleterious, even in severely ill COPD
patients ( eg pH <7.2)
(Conti et al 2002, Squadrone et al 2004)
The “scant & conflicting data” suggests a cautious
trial of NIV in COPD pts with severe pneumonia is
warranted.
Predict failure?
Review by Peñuelas et al.
CMAJ
2007;177(10):1211-8
Sinuff et all Chest2003;123:2062-73
Obtunded Patient
3. Is there a role for NIPPV in the obtunded
hypercarbic COPD patient?
Gord

Noninvasive Positive-Pressure
Ventilation To Treat Hypercapnic Coma
Secondary to Respiratory Failure
Gumersindo Go´nzalez Dý´az,et al CHEST 2005; 127:952–960
The randomized studies excluded pts with
decreased LOC
 Concern of aspiration risk
 International consensus conference
considered GCS <10 as
contraindication
 Never evaluated prospectively

Decreased LOC
Prospective, observational study
between January 1, 1997, and May 31,
2002
 Patients with GCS score <8 and CO2
retention formed one group, and those
without coma served as a comparison
group.
 Excluded if another cause for LOC was
found

Decreased LOC
Total of 958 pts started NIPPV
 95 (10.1%) had GCS scores on
admission <8
 NIPPV success was similar in both
groups
 hospital mortality was not significantly
different

Outcomes
Conclusions for Coma

Coma should no longer be considered a
contraindication to NPPV therapy.
NIPPV in Patients With Acute Exacerbations of
COPD and Varying Levels of Consciousness
Scala, et al; CHEST 2005; 128:1657–1666
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
A 5-year case-control study with a
prospective data collection.
Study confirms that NPPV may be
successfully applied to patients experiencing
COPD exacerbations with milder ALCs, the
rate of failure in patients with severely ALCs
(ie, Kelly score > 3) is higher, though better
than expected, so that an initial attempt with
NPPV may be performed
Ventilation

You decide to intubate the patient instead and it
goes ahead smoothly. Your medical student said
he had heard these patients can get auto peep and
that it can be BAD!
4. What would be your initial ventilator settings
including what measures can be done to minimize
auto peep in the ventilated COPD patient?
Yoan

Goals for COPD patients
Adequate patient monitoring
 Optimize ventilator settings to minimize
excessive work of breathing
 Assure Synchrony
 Detect auto-PEEP and prevent barotrauma
 Prevent further respiratory muscle atrophy
 Intubate using the widest diameter ET tube
possible (R = 8nl / πr 4)

Mechanical Ventilation
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Mode?
Volumes/Pressures?
Flow Rate?
RR?
pH?
I:E ratio?
PEEP?
FiO2
Auto-PEEP
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When the expiratory time is not long
enough to allow exhalation of all tidal
volume auto-PEEP is generated.
Airway Pressures
PEEPi + PEEPe
Ranieri et al Eur Respir J, 1996, 9, 1283–
1292
The Unit

The patient is brought up to “The Unit” and
your Jr has finished the admission orders
and wants to review them with you.
5. What treatments do you want to ensure
the patient receives?
Yoan
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Orders
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Sedation?
Bronchodilators?
Steroids?
Antibiotics?
Nutrition?
Insulin?
Heliox?
Further investigations?
Weaning

After a few days, some improvement is seen. His
FiO2 requirements are 30% and his lungs sound
much clearer. He has also been weaned down to
pressure support. The RT mentioned the weaning
indices for the day with a PO2/FiO2=300, RSBI of
120. Your medical student looks confused and
asks:
6. What are weaning indices and what is the
evidence for their use?
Yoan

RSBI
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This is f/VT
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Yang, KL, Tobin, MJ (1991) A prospective study
of indexes predicting the outcome of trials of
weaning from mechanical ventilation. N Engl J
Med 324,1445-1430
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Shown to be predictive of extubation if
<105
RSBI
Risk Factors for Extubation Failure in
Patients Following a Successful
Spontaneous Breathing Trial
Frutos-Vivar, et al 2006;130;1664-1671 Chest
Spontaneous Breathing Trial
ELY et al; N Engl J Med 1996;335:18649.)
 RCT of 300 vented pts in ICU&CSICU
 All pts screened daily for PaO2/FiO2>200,
PEEP<5, f/Vt <105, good cough, no
pressors
SBT
Intervention group then underwent SBT for
2 hours that morning
 If passed a note was left on the chart
 Controls only had the daily assessment

SBT results
Asynchrony

Five days later, your patient is still requiring a
PSV of 10 and PEEP 5. The RT notes some
asynchrony as well. The bright Jr resident pipes
up and says he heard about a different form of
ventilation called PAV that might help with this.
7. What is PAV and how does it work?
Steve

PAV (Proportional Assist Ventilation)
ventilator amplifies the patient's
inspiratory effort without any
preselected target volume or pressure
 Aim is to allow the patient to attain their
own ventilation and breathing pattern

Younes M. Proportional assist ventilation, a new approach to
ventilatory support. Am Rev Respir Dis 1992;145:114–20
PSV vs PAV
Varelmann, et al; Crit Care Med 2005;
33:1968 –1975)
 12 pts in randomized clinical crossover
 Increasing vent demand by adding dead
space
 Cardiorespiratory, ventilatory, and work
of breathing variables were assessed
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Results
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No major differences in
cardiorespiratory function between
dynamic and constant inspiratory
pressure assistance.
PAV
8. Is there evidence it helps with patient
vent asynchrony?
Steve

Giannouli, et al. Response of ventilator dependent patients to
different levels of pressure support and proportional assist. Am J
Respir Crit Care Med. 1999;159:1716 –1725.

found lower rates of ineffective
triggering with PAV than with PSV,
because tidal volume was smaller at
high levels of assistance and because
ventilator insufflation time was limited
Asynchrony
9. What other techniques can be used to
decrease asynchrony?
Steve

Adjusting the Inspiratory Trigger
 Adjusting PEEP
 Adjusting the Pressure Support Level
 Increasing the expiratory trigger (%
inspiratory flow)
 Neurally adjusted ventilatory assist
(NAVA)
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VIDD
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After 10 days in the unit the patient is still unable
to fully wean off the ventilator. During rounds
your great and mighty staff asks you:
10. What is ventilator induced diaphragm
dysfunction-VIDD and how does it effect
weaning?
Scott
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VIDD
a loss of diaphragmatic force-generating
capacity that is specifically related to the
use of mechanical ventilation.
 Inactivity of diaphragm during MV
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VIDD
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VIDD is a diagnosis of exclusion based
on
 (1) an appropriate clinical history of
having undergone a period of
controlled mechanical ventilation
(CMV), and
 (2) other possible causes of
diaphragmatic weakness having been
sought and ruled out
Atrophy, oxidative stress, myofibrillar
disruption, and various remodeling
responses within diaphragm muscle
fibers
 Animal studies suggest that the onset of
VIDD during CMV is rapid
 Minimize non-spont vent, steroids and
maximize nutrition
 antioxidants?

Tracheostomy

She then asks you if we should consult for a
trach in this patient?
11. When is the best timing for a
tracheostomy and does it reduce ICU length
of stay?
Scott
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Trach Timing
lack of adequately sized, randomized,
prospective controlled studies
 most recommendations are based on
consensus opinions of clinical experts
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Trach
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Indications for tracheostomy include
 failure of extubation,
 upper airway obstruction,
 airway protection and airway access
for secretion removal,
 avoidance of serious oropharyngeal
and laryngeal injury from prolonged
translaryngeal intubation
MacIntyre NR, Cook DJ, Ely EW Jr, et al.
Chest 2001; 120 (6 Suppl):375S–395S.
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ACCP guidelines suggest that
tracheostomy should be considered
after an initial period of stabilization on
the ventilator (generally, within 3–7
days), when it becomes apparent that
the patient will require prolonged
ventilator assistance
Groves and Durbin Jr,Current Opinion in Critical
Care 2007, 13:90–97
Review of literature on trachs
 a number of retrospective studies and a
single prospective study have shed
some light on timing of trach
 Most reports favor the performance of
tracheostomy within 10 days of
respiratory failure

Summary of Trials
Sleep

The nurse also mentions the patient has
been having difficulty sleeping most nights
(who doesn’t).
12. What is the impact of ventilator
settings on sleep patterns?
Scott
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Parthasarathy; Am J Respir Crit Care Med Vol 166.
pp 1423–1429, 2002
performed polysomnography on 11 critically ill patients
 examined whether the presence of
backup rate on assist-control ventilation
would decrease apnea-related arousals
and improve sleep quality.
 patients receiving mechanical
ventilation have severely fragmented
sleep
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Sleep
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the number of arousals and awakenings, was
greater during pressure support than during
assist-control ventilation: 79+7 versus 54+7
events per hour (p=0.02)
6 pts had central apneic episodes on PSV
addition of dead space produced a mean
increase in end-tidal CO2 of 4.3 mm Hg,
which resulted in a decrease in the frequency
of central apneas
PAV vs PSVin Sleep
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Bosma, et al; Crit Care Med 2007; 35:1048–1054
13 pts in crossover study
Overall sleep quality was significantly improved on
proportional assist ventilation (p < .05) due to the
combined effect of
 fewer arousals and awakenings per hour (3.5 vs.
5.5),
 and greater rapid eye movement (9% vs. 4%) and
slow wave sleep(3% vs. 1% )

Patient-ventilator asynchronies per hour
were lower with PAV than with PSV (24
vs. 53 ; p =.02) and correlated with the
number of arousals per hour (RR =.65,
p=.0001).
BiPAP and re-intubation
The next day the patient is on PSV 6 and PEEP of
5, is alert, afebrile, and has and passed his SBT.
You feels it is time to pull the tube. 1 hour later,
the patient becomes tachypneic and looks like he
might fail extubation. Your very astute Jr said he
has read something about using BiPAP to prevent
re-intubation.
 13. What is the evidence to use BiPAP to
extubate/prevent re-intubation?
Dave

NIPPV and Extubation
Keenan, et al; JAMA. 2002;287:32383244
 RCT
 81 patients who required ventilatory
support for more than 2 days and who
developed respiratory distress within 48
hours of extubation.
 Stnd therapy vs NIPPV+Stnd therapy

Results
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there was no difference in the rate of
reintubation (72% vs 69%; relative risk,
1.04; 95% confidence interval, 0.781.38) or hospital mortality (31% for both
groups; relative risk, 0.99; 95%
confidence interval, 0.52-1.91).

Pts with COPD were excluded after 1
year because they thought it was
unethical due to strong established
literature supporting the use of NPPV
for COPD exacerbations
NIPPV for Respiratory Failure after Extubation
Esteban, ET AL; N Engl J Med 2004;350:2452-60.
Multicenter, randomized trial
 Electively extubated after mechanical
ventilation and who had respiratory
failure within 48 hours
 There was no difference found (rate of
reintubation, 48% in both groups; RR in
the NIPPV group, 0.99; 95 percent CI,
0.76 to 1.30).

Rate of death in the intensive care unit
was higher in the NIPPVgroup (25% vs.
14%; RR 1.78; 95 percent confidence
interval, 1.03 to 3.20; P=0.048)
 Likely due to increase time to reintubation
 Only 10% had COPD

Noninvasive positive-pressure ventilation in acute
respiratory failure
Peñuelas et al, CMAJ 2007;177(10):1211-8
Review of literature
 the early use of NIPPV can prevent
respiratory failure after extubation and
decrease the need for reintubation.
 further studies that better define the
population of patients at risk for
respiratory failure after extubation may
be necessary.

Prognosis

The patient does well and only requires
BiPAP for 12 hours. Your medical student
then asks:
14. What is the short and long-term
prognosis for a person with COPD who has
required mechanical ventilation?
Dave

Exacerbation of COPD: A Retrospective Study
In-Hospital and 5-Year Mortality of Patients Treated in the ICU for
Acute
Chua Ai-Ping, et al; Chest 2005;128;518-524
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Retrospective cohort study of 57 patients
More than 90% of patients required intubation
The in-hospital mortality rate for the entire
cohort was 24.5%.
mortality rates at 6 months and 1, 3, and 5
years were 39.0%, 42.7%, 61.2%, and
75.9%,
median survival time for all patients was 26
months.
Outcome
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3-month mortality rate after ICU discharge
was 11%.
only IBW predicted three-month survival rate
Vitacca, et al; CHEST 2005
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Hospital mortality 15% (predicted 30%)
Incidence of sepsis and number of organ failures
were higher in non-survivors
Afessa et al, Crit Care Med 2002
Lung Reduction Surgery

The patient’s son arrives from Scotland and thanks
you all for the wonderful care of his father. He
then states that he has been reading on Lung
Volume Reduction Surgery and wonders if it
would help his father.
15. What is LVRS and is there evidence of benefit
in COPD?
Dave

LVRS
•First introduced by
Brantigan in 1957
Brantigan, A surgical approach to
pulmonary emphysema. Am Rev
Respir Dis 1959; 80:194.
A randomized trial comparing lung-volume-reduction
surgery with medical therapy for severe emphysema.
Fishman et al, N Engl J Med 2003 May 22;348(21):2059-73
 1218
pts with severe emphysema
underwent pulmonary rehab and were
randomly assigned to LVRS or to receive
continued medical treatment
 Overall, surgery increases the chance of
improved exercise capacity but did not
confer a survival advantage over medical
therapy
 There
was a survival advantage for
patients with both predominantly upperlobe emphysema and low base-line
exercise capacity.
The Effect of Lung Volume Reduction Surgery on
Chronic Obstructive Pulmonary Disease Exacerbations
Washko et al; Am J Respir Crit Care Med Vol 177. pp 164–169,
2008

To examine the effect, and mechanism
of potential benefit, of LVRS on COPD
exacerbations by comparing the
medical and surgical cohorts of the
National Emphysema Treatment Trial
(NETT).
LVRS
no difference in exacerbation rate or
time to first exacerbation between the
medical and surgical cohorts during the
year before study randomization
 Post randomization, the surgical cohort
experienced an approximate 30%
reduction in exacerbation
frequency(P=0.0005)
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LVRS increased the time to first
exacerbation in both subjects with and
without a prior history of exacerbations
(P=0.0002 and P=0.0001, respectively)
Effect of Bronchoscopic Lung Volume Reduction on Dynamic
Hyperinflation and Exercise in Emphysema
Nicholas, et al; Am J Respir Crit Care Med Vol 171

Endobronchial valve placement can
improve lung volumes and gas
transfer in patients with chronic
obstructive pulmonary disease and
prolong exercise time by reducing
dynamic hyperinflation.
Bonus Time

Bonus questions: 1. Is there any evidence
that Cold-FX works?
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2. Should this patient have his large ventral
hernia repaired in the future and if so, using
what technique?
Hernia Repair
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Factors to consider
 Size of hernia and risk of incarceration
 Overall health of patient
 Lap vs Open