Download Objectives Objectives - Academy of Acute Care Physical Therapy

1/17/2012
Objectives
• Identify types of airways and indications
Understanding Mechanical
Ventilation and its Implications for
Physical Therapy Intervention
• Identify common modes of ventilation and
describe the assistance that each mode
provides
• Interpret common alarms associated with
mechanical ventilation and indicate actions
• Describe possible complications associated
with mechanical ventilation
Jennifer M. Zanni, PT, DScPT
Clinical Specialist, Johns Hopkins Hospital
Lecturer, Johns Hopkins University
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Why is mechanical ventilation
required??
required
Objectives
• One of the most common indications for using
mechanical ventilation is to decrease the work
of the respiratory musculature and improve
arterial oxygenation
• Discuss and synthesize common weaning
parameters and methods
• Describe treatment strategies for mobilizing
the patient requiring mechanical ventilation
• Patients in acute respiratory failure can have 46x the normal inspiratory effort
• Discuss current literature regarding
rehabilitation of patients requiring mechanical
ventilation
• Careful selection of vent support and settings
is crucial and needs to be individualized to
each patient
Tobin, MJ. NEJM, Vol. 344, No. 26, June 28, 2001
1/17/2012
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Why is mechanical ventilation
required??
required
4
Why is mechanical ventilation
required??
required
• In a study of 1638 patients (8 countries) who
required mech vent:
• Impending or existing respiratory failure
– Failure to oxygenate
– Failure to Ventilate
– Or combination of the two
– Acute Respiratory Failure (66%)
• ALI/ARDS, heart failure, pneumonia, sepsis, trauma,
surgery complications
– Coma (15%)
– Acute on chronic COPD (13%)
– Neuromuscular disorders (5%)
• Airway protection
Esteban, A et al. Am J Respir Crit Care Med. 2000;161:1450-8.
Tobin, MJ. NEJM, Vol. 344, No. 26, June 28, 2001
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Failure to Ventilate
Failure to Oxygenate
• Hypercapnic Respiratory Failure
• Hypoxic Respiratory Failure
– Caused by disorders of CNS, neuromuscular
systems, chest wall or airways
– Increased PaCO2 > 50 mmHg
– s/s include tachypnea, agitation, cyanosis, and
decreased mental status
• Inadequate exchange of gases at the alveolar level,
as seen in ARDS
• Decreased PaO2 (<50 mmHg)
– Can occur despite normal ventilation
– Occurs at pulm-alveolar interface due to pulm
edema or fibrosis
– Reduced diffusing capacity and V/Q mismatch
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Acute Lung Injury/
Injury/ Acute
Respiratory Distress Syndrome
Failure to Oxygenate
A big challenge in mech ventilation are in alveolar-filling
disorders (ALI/ARDS) causing pulm edema and stiffness
in the lungs, making them difficult to ventilate
• Clinical presentation
– Acute onset
– Bilateral infiltrates
– Severe dyspnea and tachypnea
– Hypoxemia
• PaO2/FiO2 < 300 (ALI)
• PaO2/FiO2 < 200 (ARDS)
• Can be caused by a variety of factors, usually
inflammatory in nature
Tobin, MJ. NEJM, Vol. 344, No. 26, June 28, 2001
– Pulmonary (pneumonia) vs. extra pulmonary
(sepsis)
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Fan E et al., JAMA 2005;294:2889-2896.
Respiratory Failure
• Patients at risk for alveolar rupture from mech
vent
• Benefits have been shown with using lower
tidal volumes
• May benefit from prone positioning to allow
ventilation to be distributed more evenly
throughout the lungs
Types of Ventilation
Tobin, MJ. NEJM, Vol. 344, No. 26, June 28, 2001
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Positive vs. Negative Pressure
Ventilation
Things to consider…
• Negative Pressure
• What type of airway is in place?
• What are the ventilator settings and what do
they all mean?
• What do I do if the vent alarms?
• What to I do if the vent fails?
• How do I plan treatment in conjunction with
vent weaning?
– Mimics more normal chest mechanics with
respiration
– Assists with failure of ventilation, but not
oxygenation
– “Iron lung
• Positive Pressure
– Most common
– Opposite of “normal” breathing
http://www.ccmtutorials.com/rs/mv/page4.htm Accessed on 12/2/11
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Airway Management
• Endotracheal Tube
(ETT)
Start with the ABC’s…
Airway
• Can be placed
orally (most
common) or nasally
• Passes through the
vocal cords
Airway Management
Airway Management
• Tracheostomy tube
• Cuff vs Cuffless
• Inserted below the
vocal cords
• Used in more longterm airway
management
•
Airway cuffs:
– Assists with holding the airway in place
– Allows positive pressure ventilation without loss
of tidal volume
– May reduce risk of aspiration of oral and gastric
secretions
– If pt can talk or is losing tidal volume…cuff may
not be fully inflated
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Challenges to Mechanical
Ventilation
Ventilator Settings
•
•
•
•
•
• Tidal volumes too large can over-inflate lungs
and cause alveolar damage
Tidal Volume
PEEP
Mode
Rate
FiO2
• Tidal volumes too small may increase dead
space
• The goal is to use vent settings to optimize gas
exchange without damaging the lungs
• Unfortunately, there is no evidence to support
one ideal mode or setting of mech ventilation
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Actual
resp rate
PEEP
•
Type of
respiration
Positive End-Expiratory Pressure
–
–
–
–
Mode
& Rate
FiO2
PEEP
Pressure given in expiratory phase to prevent closure of
the alveoli and allow increased time for O2 exchange
Used in pts who haven’t responded to treatment and are
requiring high amt of FiO2
PEEP will lower O2 requirements by recruiting more
surface areas
Normal PEEP is approximately –5cmH20. Can be as high
as –20cmH20
– Risks include barotrauma, ptx, and decreased
cardiac output
Oxygen Therapy
• Prolonged exposure to high levels of oxygen
can be toxic to the lungs
• High FiO2 (>.5) can lead to atelectasis
Modes of Ventilation
• Balancing act between FiO2 and PEEP
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Modes of Ventilation
•
Controlled Ventilation
Modes of Ventilation
•
Assist Control (A/C)
–
Vent provides a preset resp rate, TV, and
inspiratory flow rate
– Will allow a pt to initiate a breath and then vent
will deliver a preset tidal volume
– Machine set at a minimum rate so apnea will not
occur if the pt does not initiate a breath
– Disadvantages:
• Hyperventilation if pt has increased resp rate
(can lead to resp alkalosis)
• Vent dysynchrony, breath-stacking
– Vent initiates all breaths at a preset rate and
tidal volume
– Vent will block any spontaneous breaths
– Used mainly in the OR for paralyzed and sedated
patients.
Modes of Ventilation
•
Synchronized Intermittent Ventilation (SIMV)
Modes of Ventilation
•
Pressure Support Ventilation (PSV)
– Pt initiates breath & vent delivers a preset
inspiratory pressure to help overcome
airway resistance
– Patient controls the rate, tidal volume, flow
rate and duration of inspiration
– Pts may be more comfortable on PS
– Tidal volume is variable
– Can be used in conjunction with SIMV or
CPAP settings
– Similar to A/C, but pts can take own breaths
with their own TV between mechanically
assisted breaths
– Can be used as a primary mode or a weaning
mode
– May lead to a low resp rate in a pt who does not
initiate breaths if rate is set low
Modes of Ventilation
•
Pressure Support Ventilation (PSV)
–
–
–
Higher amounts of PS needed when lung
compliance is decreased or airway
resistance is high or when the patient can
only make weak inspiratory efforts
PS 5 (low amount)
PS 10 or greater (high amount)
–
Commonly used as a weaning mode
Modes of Ventilation
•
Pressure Control (PC)
–
–
–
Similar to pressure support, but a preset
resp rate is set if the patient is not
spontaneously breathing
If the pt is spontaneously breathing, this
will function similar to pressure support
May be used in ALI/ARDS to avoid
barotrauma
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Modes of Ventilation
•
Continuous Positive Airway Pressure (CPAP)
– Constant positive airway pressure provided
during both inspiration and expiration
– Vent provides O2 and alarms, but no respirations
– Improves gas exchange and oxygenation in pts
able to breathe on their own
– Can also be used non-invasively via a face or
nasal mask for sleep apnea pts
Non--Invasive Ventilation (NIV)
Non
• Bi-Level Airway pressure (BiPAP)
– Delivered by mask, not through an airway
– Similar to CPAP, but can be set at one pressure for
inhalation and another for exhalation.
– Used in sleep apnea but also has been found to be
useful in some patients with respiratory failure to
avoid intubation
Non-Invasive Ventilation (NIV)
Non-Invasive Ventilation (NIV)
• Allows the patient to be able to speak and eat
• Avoids the risks associated with intubation,
sedation
• No protection against aspiration
• Used in decompensated COPD, CHF, hypoxic
and hypercapnic respiratory failure, DNI
patients
• Some emerging evidence in a few small
studies that in patients with severe COPD,
exercise while on NIV improves 6 MWT, LE
muscle fatigue, and oxidative threshold when
compared to the use of supplemental O2
alone
Borghi-Silva A, et al. Respiratory Care. July 2010(58)7, pp. 885-894.
Toledo A, et al. Clinics (Sao Paulo). 2007; 62(2):113-20
Borghi-Silva A, et al. Respirology. 2009, 14, pp. 537-544
Modes of Ventilation
•
High frequency oscillatory ventilation (HFOV)
– Sets a mean airway pressure, but minimal
change in tidal volume
– Airway pressure is set so that alveoli remain
open and “oscillate”
– Small tidal volumes minimize barotrauma
– Inspiratory and expiratory phase are both active
– Was used primarily in neonates, but now also
being used in adults with ARDS/ALI.
– Goal is to wean back to regular mech vent
Modes of Ventilation
• Airway Pressure Release Ventilation
(APRV)
– Differs from conventional vent
– Cycles between 2 levels of airway pressures to
assist with gas exchange
– Elevation of airway pressures with brief
intermittent releases of airway pressure
– Facilitates oxygenation and CO2 clearance
– May be an improved way to treat ALI/ ARDS
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Vent Alarms
•
Vent Alarms
High Pressure Alarm (common alarm to
come and go…more serious if it
continues to alarm)
–
–
–
–
–
–
–
•
– Pt pops off vent
– Leak in cuff or tubing connections (if patient
can talk around trach, a leak in the cuff is
probable)
– Extubation
Secretions/ needs to be suctioned
Pt biting tube/ fighting vent
Water in tubing
Bronchospasm
Pneumothorax
Decreased compliance (i.e. ARDS)
Kinked tubing/ malposition of ETT
Vent Alarms
•
Other Alarms
–
–
–
–
–
Tidal volume (high, low)
Resp rate (high, low, apnea
Temperature
Oxygen supply
Power
Vent Alarms
•
General principles…
– Look at the pt first!!! Then follow tubing to the
vent to search for any disconnections
– If can’t find the problem and the patient is in
distress, disconnect the patient from the vent
and bag with 100% O2 (and call for help)
Complications of Mech Vent
•
•
Asynchrony (“bucking”)
Auto PEEP
– Pt doesn’t expire full tidal volume and air
become trapped
•
Barotrauma
– Damage to alveoli caused by increased
pressure and volume
Low Exhaled Volume/ Circuit Disconnect
Alarm
Complications of Mech Vent
•
•
•
•
•
•
Hemodynamic compromise
Nosocomial infection
Anxiety/ Stress/ Sleep deprivation
Ulcers/ Gastritis/ Malnutrition
Muscle deconditioning/ Vent
dependence
Increased intrathoracic pressure can
cause systemic edema due to decreased
venous return
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Weaning Parameters
• Weaning is one of the most challenging tasks
in the ICU
• Up to 25% of patients will have resp distress
requiring re-initiation of mech vent support
Weaning Parameters
• However, a patient’s ability to breathe on their own
is often underestimated
• 50% of patients who self-extubate do not require reintubation
Epstein, SK. Contemporary Crit Care. 7(8), Jan 2010, 1-8
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Weaning Parameters
Weaning parameters
• No routine application of weaning parameters
– Consider weaning only when evidence of clinical
improvement, adequate oxygenation, stable
hemodynamics, and the patient is able to breathe
spontaneously with appropriate resp mechanics
• Adequate Oxygenation
– PaO2 >60-70 on FiO2 .4 to .5 and PEEP 58cmH20
– PaO2/FiO2 ratio >150-200
• Adequate Ventilation
Epstein, SK. Contemporary Crit Care. 7(8), Jan 2010, 1-8
– PaCO2 35-45mmHg
– PH 7.3 to 7.45
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Weaning parameters
• Types of weaning trials
– Pressure Support/ CPAP
– SIMV with Pressure Support
– T-piece trial
– Extubation to NIV
Spontaneous Breathing Trials
• Spontaneous breathing trials (whether single
or multiple trials) led to extubation more
quickly than those receiving Pressure Support
and IMV for weaning purposes in patient who
are mechanically ventilated for > 1 week
Esteban, A et al. (1995, Feb 9). N Engl J Med, 332(6):345-50
.
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Weaning Parameters
•
Signs of distress during weaning…
– Increased tachypnea (>30)
– Increased heart rate
– Irregular breathing pattern or use of accessory
muscles
– Agitation or panic unrelieved by assurance
– Decrease pH to less than 7.25-7.3 with
increasing PCO2
Treatment Considerations
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Treatment Guidelines
• Patients weaning from mechanical
ventilation
– Consider each patient’s case and determine
their ability to tolerate both spontaneous
breathing trials (SBTs) and rehab sessions
– May be optimal to treat prior to SBT or after
they are rested
– Consider mobility and strengthening 1st, then
weaning
Treatment Guidelines
• Communication and teamwork are
essential for optimal treatment
coordination
.
.
.
.
Treatment Guidelines
•
Consider the need for increased FiO2 or vent
support prior to mobilizing a pt in order to
maximize their pulmonary status. Communicate
with medical team to discuss best settings
•
Treatment Guidelines
•
Oxyhemoglobin dissociation curve
–
Remember that SaO2 below 90% represents
large changes in PaO2
Consider reason for resp failure?
–
–
–
Failure to oxygenate?
Failure to ventilate?
Both?
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Ambulating a Patient on
Mechanical Ventilation
Ambulating a Patient on
Mechanical Ventilation
• Requires teamwork with the entire medical team
• Most standard ventilators do not run on battery.
Will likely need to use a portable ventilator or a
ambu-bag to ventilate the patient while
mobilizing
Steps to mobilizing a patient on
mechanical ventilation
•
ETT placement
–
–
•
Make sure tape is secure prior to moving pt!!!
Look at cm mark at lip before and after treatment to
assure no movement had occurred
May want to talk with team if patient has an
FiO2 of .60 or greater and/or if PEEP is -10cm
H2O or greater to ensure medical stability
Literature Highlights
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Early Mobility in the ICU
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Early Mobility in the ICU
•Prospective study of 103 consecutive pts admitted to
RICU over 6 mo period
• 40% of all mobility activities were performed with
an endotracheal tube in place
•Criteria for inclusion for early activity:
• At RICU discharge…
–MV requirement >4 days
–Neurologic: response to verbal stimuli
–Respiratory: FIO2<0.6, PEEP<10 cm H2O
–Cardiovascular: No orthostatic hypotension or pressors
– 64% (23) of patients age 65 or greater ambulating
more than 100ft
– 74% (36) of patients less than 65 ambulating more
than 100 ft
•Activity goal: ambulate >100 ft before ICU d/c
Bailey P et al. Crit Care Med. 2007, Vol 3(1)
Bailey P et al. Crit Care Med. 2007, Vol 3(1)
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Early Mobility in the ICU
• Transfer of patients to an ICU which promoted
mobility resulted in almost a 3-fold increase in
ambulation
• This improvement in ambulation was not
explained by improvements in physiology
Early Mobility in the ICU
• RCT with early PT and OT for mechanically ventilated
adults (usual care vs. intensive PT/OT co-treatment.
Both groups got daily sedation interruption)
• Sessions begun with PROM if pt was unresponsive
and progressed as patient tolerated to include
AAROM/AROM, ADLs, and mobility
Schweickert, W.D. et al. (2009, May 30. Lancet. 373(9678), 1874-1882
Thomsen SE et al. (2008). Crit Care Med. 2008. Vol 36(4): 1119-1124.
Early Mobility in the ICU
• Pts in intervention group had…
– Shorter duration of delirium (median 2 vs 4 days)
– More ventilator free days (median 23.5 vs 21.1 days)
– Improved return to independent functional status (59% vs.
35%)
– No difference in LOS
Early Mobility in the ICU
• Multi-disciplinary QI project to decrease sedation
and increase PT and OT services in a medical ICU
• Changes in sedation practices made from continuous
infusion to a prn basis
• Patients were more alert, less delirious, and had low
pain scores
Needham DM et al. (2010, Apr). Arch Phys Med Rehabil. 91(4):536-42
Schweickert, W.D. et al. (2009, May 30. Lancet. 373(9678), 1874-1882.
Early Mobility in the ICU
• Results of QI project:
– Increased numbers of patients receiving PT
and OT services and increased numbers of
treatment sessions
– Deep sedation was not necessary for patient
comfort
– Decreased ICU and hospital length of stay
(2.1 and 3.1 days respectively)
Thank you!
[email protected]
1/17/2012
Needham DM et al. (2010, Apr). Arch Phys Med Rehabil. 91(4):536-42
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Additional References
• Bailey, P.P., Miller, R.R., 3rd, & Clemmer, T.P. (2009, Oct).
Culture of early mobility in mechanically ventilated
patients. Crit Care Med, 37(10 Suppl):S429-35.
• Clini, E & Ambrosino, N. (2005, Sep). Early physiotherapy
in the respiratory intensive care unit. Respiratory
Medicine, (9):1096-104.
• Ciesla, N. D. (2004). Physical therapy associated with
respiratory failure. In DeTurk, W.E and Cahalin, L.P (Eds.),
Cardiovascular and Pulmonary Physical Therapy (pp. 541587). New York: McGraw-Hill.
• Dean, E. (2008). Mobilizing patients in the ICU: Evidence
and principles of practice. Acute Care Prospectives, Vol.
17(1).
Additional References
• Hopkins, R.O., & Spuhler, V.J. (2009, Jul-Sep). Strategies
for promoting early activity in critically ill mechanically
ventilated patients. ACCN Adv Crit Care, 20(3):277-289.
• Irwin, S and Tecklin, JS. (2004). Cardiopulmonary
Physical Therapy: A Guide to Practice, (4th ed.). St Louis:
Mosby.
• Perme, C., & Chandraskekar, R.K. (2008). Managing the
patient on mechanical ventilation in ICU: Early mobility
and walking program. Acute Care Prospectives,Vol
17(1).
• Sadowsky, H.S. Monitoring and life support equipment.
In E.A. Hillegass and H.S. Sadowsky, Essentials of
cardiopulmonary physical therapy. (pp. 509-533). 2001;
Philadelphia: Saunders.
Additional References
• Fessler, H.E. & Hess, D.R. (2007). Respiratory
controversies in the critical care setting. Does highfrequency ventilation offer benefits over conventional
ventilation in adult patients with acute respiratory
distress syndrome? Respiratory Care. 2007. 52, (5), 595605.
• Frownfelter, D. (1987). Chest Physical Therapy and
Pulmonary Rehabilitation. (pp. 729-744). St. Louis:
Mosby.
• Frowley PM and Habashi, NM. Airway Pressure Release
Ventilation: Theory and Practice. AACN. 2001;Vol 12(2),
234-246.
Additional References
• Stawicki, S.P., Goval, M., & Sarani, B. (2009, Jul-Aug).
Frequency oscillatory ventilation (HFOV) and airway
pressure release ventilation (APRV): a practical guide. J
Intensive Care Med, 24(4):215-29. Epub 2009 Jul 17.
• Tobin, MJ. (2001, June 28) Advances in mechanical
ventilation. NEJM, 344(26) Yosefy, C., Hay, E., & Ben-Barak,
A. (2003). BiPAP ventilation as assistance for patients
presenting with respiratory distress in the department of
emergency medicine. American Journal of Respiratory
Medicine. 2(4), 343-7.
• Zanni, J.M., & Needham, D.M. (2010, May). Promoting early
mobility and rehabilitation in the intensive care unit. PT in
Motion, 32-39
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