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TSRC 37th Annual Convention Critical illness Myopathy & Critical illness Polyneuropathy


TSRC 37th Annual Convention Critical illness Myopathy & Critical illness Polyneuropathy By Elizabeth Kelley Buzbee AAS, RRT, NPS Lone Star System- Kingwood [formerly ... – PowerPoint PPT presentation

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Title: TSRC 37th Annual Convention Critical illness Myopathy & Critical illness Polyneuropathy

TSRC 37th Annual Convention Critical illness
Myopathy Critical illness Polyneuropathy
  • By Elizabeth Kelley Buzbee AAS, RRT, NPS
  • Lone Star System- Kingwood formerly known as
    Kingwood College

Failure to wean due to muscle weakness
  • The effect of invasive mechanical ventilation on
    the patients ventilatory skeletal muscles is a
    well-known yet fairly complex problem.
  • Full ventilatory support can trigger muscle
    atrophy within 72 hours in adults. According to
    MacIntyre, both muscle mass and cross-section of
    muscle fibers are affected. MacIntyre pp.
  • There is.. evidence of oxidative stress and
    protein breakdown in the muscles. MacIntyre pp.
  • When a patients FRC is raised above normal by
    PPV, the effect on resting muscle length results
    in a decrease in muscle strength. MacIntyre pp.
  • Alterations in the blood flow to the ventilatory
    muscles secondary to PPV just adds to the
    problem. MacIntyre pp. 1
  • Not only is muscle strength affected, we will see
    a decrease in muscle endurance. MacIntyre pp. 1

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Other problems are more subtle
  • malnutrition electrolyte imbalances
  • The effects of malnutrition on the pulmonary
    system are distinct and well known.
  • Patients who cannot take oral nutrition may be
    on IV glucose, which is fine for a day or so, but
    TPN with its more complete nutritional support is
    needed to keep metabolism going.
  • Carbohydrates are needed for both the diaphragm
    and the myocardium Peters pp. 350
  • The effect of electrolyte imbalances on the
    myocardium is well-known but potassium levels can
    also affect skeletal muscle action of the chest
    and abdominal muscles.
  • Hypokalemia can cause muscle weakness even
    paralysis Garth
  • while hyperkalemia also results in muscle
    weakness and flaccid paralysis
  • serum magnesium levels of 8.0-10.0 mEq/L are
    associated with flaccid skeletal muscle
    paralysis. Novello

The new threat in the ICU
  • There are new problems discovered in the ICU that
    result in various degrees of muscle
    weakness--even paralysis-- that can keep a person
    from weaning off mechanical ventilation Dhand
    pp. 1025
  • But is this a new problem? A review of the
    literature shows that as early as the 1970s, a
    small number of severe asthmatic patients who
    were intubated, paralyzed and ventilated had
    significant, generalized muscle weakness.
  • Critical illness polyneuropathy
  • Critical illness myopathy
  • Prolonged neuromuscular blockage

Occurrence of CIP, CIM or a combination of the two
  • as many as 30-50 of patients with critical
    illness. Dhand pp. 1026
  • Another study n206 found 25 of critical care
    patients who had been mechanically ventilated for
    more than 7 days had a degree of muscle weakness.
    This study included only persons who were awake
    and responsive Deems pp. 1043

Critical illness myopathy
Critical illness myopathy
  • According to the American College of
    Rheumatology, myopathy is a disease of the
    muscles. The actual manifestation of the muscle
    disease varies widely based on etiology and the
    location of the defect.
  • In the case of CIM, we seem to have a syndrome of
    symmetric weakness of all extremities, of muscle
    wasting, hyporeflexia and failure to wean from
    mechanical ventilation. Dhand pp. 1036

Risk factors for Critical illness myopathy
  • Persons who have received high levels of
    corticosteroids neuromuscular blocking agents
  • for diseases such as severe asthma, COPD
    exacerbation, sepsis, ARDS and s/p organ
    transplants. Dhand pp. 1036

S/S of Critical illness myopathy
  • Inspection and interview of the patient
  • There also seem to be is little in the inspection
    and interview to differentiate between critical
    illness myopathy and critical illness
  • The patient will c/o weakness in both situations.

S/S of Critical illness myopathy
  • Serum Creatine Kinase
  • a product of muscle damage. Need to differentiate
    between myocardial CK and skeletal muscle CK.
    Egans pp. 351
  • Normal levels of serum creatine kinase are
    usually between 25 and 200 U/L. This test is not
    specific for the type of CK that is elevated.
  • Serum creatine kinase may be 10-100 x higher than
    normal in CIM in the first 3-4 days-- then
    stabilize after 10 days. Dhand pp. 1028

S/S of Critical illness myopathy
  • EMG the electromyogram
  • . There are two basic techniques
  • One can study a specific muscle fibers reaction
    to the insertion of a needle electrode in a
    particular muscle fiber.
  • A less-invasive procedure uses a surface
    electrode to monitor the general picture of
    muscle activation. During this study the patient
    has auditory or visual stimuli to help them know
    when they are activating the muscle. Again the
    action potential is measured
  • http//en.wikipedia.org/wiki/Electromyography
  • It is possible to perform an EMG of the phrenic
    nerve by placing the percutaneous electrode onto
    the neck at the supraclavicular fossa and
    measurements will be made at two spots along the
    anterior rib cage,
  • but the presence of a central line in either neck
    will make this EMG impossible. Dhand pp.

S/S of Critical illness myopathy
  • EMG results
  • In myopathic disorders there will be decreases in
    duration of the action potential,
  • and in the ratio of area to amplitude and in the
    number of motor unit in the muscles worse cases
    only http//en.wikipedia.org/wiki/Amplitude

S/S of Critical illness myopathy
  • Nerve conduction study
  • In the nerve conduction study the patient is
    given an electrical shock at various spots along
    a nerve.
  • Among other measurements, the velocity of the
    nerve conduction is measured at different points,
    as is the intensity of the response amplitude.
    The tester will study both the motor and the
    sensory nerve conduction. http//en.wikipedia.org/
  • In the case of CIM, there should be no real
    problems with conduction

S/S of Critical illness myopathy
  • Problems w/ Nerve conduction studies
  • in the ICU
  • the patients skin temperature will change the
    speed of conduction cool bodies result in slow
  • and the presence of pacemakers indwelling
    defibrillators can make for difficulties
    MedlinePlus nerve conduction studies
  • Picture of NCS http//0-www.nlm.nih.gov.catalog.l

S/S of Critical illness myopathy
  • What are we left with?
  • Muscle and nerve biopsy
  • Both muscle and nerve biopsy can differentiate
    between CIP and CIM and even combinations of both
    disorders. Dhand pp.1033

Critical illness polyneuropathy
Critical illness polyneuropathy
  • The Merck manual describes polyneuropathy as the
    simultaneous malfunction of many peripheral
    nerves throughout the body.
  • In CIP, with biopsy, one sees that the patient
    develops both motor and sensory degeneration
    without inflammation. Dhand pp. 1033

Risk factors for polyneuropathy
  • Poor control of blood sugar levels in diabetes
    causes several forms of polyneuropathy,
    collectively referred to as diabetic neuropathy.
    Merck Manual
  • Diphtheria toxins, autoimmune reaction, heavy
    metals such as lead and mercury and CO poisoning
    can all lead to polyneuropathy.
  • The drugs include the anticonvulsant, Dilantin,
    some antibiotics (such as nitrofurantoin and
    sulfonamides), some chemotherapy drugs and some
    sedatives such as barbital. Merck Manual

Risk factors for Critical illness polyneuropathy
  • History of sepsis, trauma, burn followed by organ
    failure, septic encephalopathy. Dhand pp. 1033.
  • in addition, according to the CDC, CIP is
    associated with a recent history of SIRV septic
    inflammatory response syndrome. CDC

S/S critical illness polyneuropathy
  • On inspection
  • Because cranial nerves are generally unaffected
    in CIP, the patients facial grimace and limb
    movement on painful stimulation may be strikingly
    different. CDC
  • A muscle biopsy would show neuropathic changes.
    Dhand pp. 1034.

S/S critical illness polyneuropathy
  • He have a normal Creatine kinase. Dhand pp.
  • he would have a reduction in both motor sensory
    nerve conduction. Dhand pp. 1029.

S/S critical illness polyneuropathy
  • EMG results
  • the EMG showed action potentials twice normal
    with increased fibers per motor unit and an
    increase in duration of the action potential.

Prolonged neuromuscular blockage
  • Nondepolarizing neuromuscular blocking agents
    such as pancuronium generally have duration of
    action of a few hours, but a few patients may
    suffer persistant weakness that can prevent
    successful weaning from ventilatory support. This
    paralysis could last additional hours--- or even
    weeks. Dhand pp. 1037

Prolonged neuromuscular blockage
Prolonged neuromuscular blockage
  • Prolonged neuromuscular blockage with
    nondepolarizing blocking agents results in
  • Prolonged neuromuscular blockade after the
    termination of long-term treatment with
    vecuronium is associated with metabolic acidosis,
    elevated plasma magnesium concentrations, female
    sex, and probably more important, the presence of
    renal failure, and high plasma concentrations of
    3-desacetylvecuronium. V Segredo

Risk factors for Prolonged neuromuscular blockage
  • Patients at increased risk seem to be those with
  • hepatic dysfunction
  • renal failure
  • acidosis
  • or hypermagnesemia Dhand pp. 1036

Differential DX
Differential DX
  • Polyneuropathies such as Guillian Barre syndrome
    can be triggered by infection,
  • while exacerbations of myasthenia gravis MG
    crisis can be triggered by stress, certain
    medications and illness.
  • Spinal cord infarction is a complication of
    aortic surgery Dhand pp. 1026.
  • myotonic dystrophy may have been undiagnosed

Differential DX
  • Guillian Barre.
  • There are no antibodies in the serum of
    patients with critical illness polyneuropathy as
    would be seen with Guillian Barre.

Differential DX
  • myasthenia gravis.
  • Patients have increasing muscle weakness with
    repetitive motions
  • they also antibodies against acetylcholine
  • tendency to have a degree of facial paralysis
    inability to protect the airway,
  • a transient improvement when given cholinesterase
    inhibitors. Egans pp. 576

Differential DX
  • Spinal cord infarction
  • Comes on suddenly and catostrophically with 80
    c/o severe pain
  • http//www.emedicine.com/NEURO/topic348.htm

Differential DX
  • myotonic dystrophy
  • Persons with myotonic dystrophy have increased
    sensitivities not only to paralytic agents, but
    to CNS depressants. Egans pp. 576

  • According to the CDC, there are no medications
    for these problems, rather we need to consider
    conservative management. CDC

We need to stop killing black widow spiders with
a sledge hammer.
May just tear up the house
Conservative measures w/ steroids
  • According to the American Heart Association 2005
    CPR guidelines, severe asthma needs to be treated
    with systemic steroids rather than topical
  • but maybe we need more studies to be done with
    inhaled dosages so that the systemic side effects
    such as myopathy can be minimized?
  • In these studies, how are these patients given
    inhaled steroids? mixed with Beta II or alone?
    SVN or MDI, DPI?
  • Exactly what are the links between
    steroid-induced diabetes and neuropathy how much
    steroid is too much?

Conservative measures w/ steroid TX
  • could we use offline measurements for intubated
  • Research is on going on the question of using
    exhaled nitric oxide monitors to fine-tune the
    level of systemic steroids in the acute
    asthmatic. Phua pp. 857
  • Offline measurement of FENO has been compared
    favorably with online modes
  • One UK single-blind study over a period of 8
    months n 116 showed no clinically significant
    improvement in controlling patients steroid
    dosages by monitoring FENO http//ajrccm.atsjourna

Conservative measures w/ Nondepolarizing
neuromuscular blockers
  • Limit time of paralysis. Sedation vacations are
    used to decrease VAP by getting patients off
    mechanical ventilation sooner. Kress
  • Maybe this same technique might be helpful with
    CIM prolonged neuromuscular blockage?

Conservative measures w/ Beta II
  • Never forget the Beta II agonists have as side
  • increases both insulin and glucose levels, when
    combining high dosage Beta II and corticosteroids
    this could get serious
  • Causes hypokalemia. According to the AHA, inhaled
    10-20 mg Albuterol over 15 will shift Potassium
    into the cell to treat both moderate severe
    hyperkalemia AHA 2005 CPR guidelines pp.
  • Compare this to the AHA recommendations regarding
    continuous Albuterol TX 2.5-5mg Q 20 minute x 3
    or 10-15 mg/hour

Conservative measures w/ Beta II
  • The AHA recommend these drugs as adjuncts to
    albuterol/IV steroid treatment
  • A trial of ipratropium bromide as adjunct to
    albuterol, possibly more that one dose AHA
  • IV Magnesium Sulfate
  • Leukotriene antagonists by IV has been studied
    but the AHA wants more research

Other bronchodilators can have neuromuscular side
  • According to the post-marketing experience with
    Singulair TM a few patients have reported
    paraesthesia hypoesthesiathese side effects
    have not been investigated yet. drug insert
  • Cromolyn Na has peripheral neuritis as a rare
    side effect 1 in 100,000
  • Magnesium by IV has respiratory failure due to
    skeletal muscle paralysis as a side effect

  • Neil MacIntyre Understanding Ventilator-Induced
    Diaphragmatic Dysfunction 
  • http//www.medscape.com/viewarticle/514526
  • Deem S. Intensive-Care-Unit-Acquired Muscle
    Weakness. Respiratory Care 2006 51(9) 1024-1041
  • Dhand, U. Clinical Approach to the Weak patient
    in the Intensive Care Unit. Respiratory Care
    2006 51(9) 1024-1041
  • Boitano, L.J. Management of Airway Clearance in
    Neuromuscular Disease Respiratory Care August
    2006, vol 51 (8) pp. 913-921.

  • Nutritional Assessment of patients with
    respiratory Disease Peters, J.A. Thomas-Peters,
    C.D., editors Wilkins Clinical Assessment in
    Respiratory Care 5th edition Elsevier-Mosby
  • Medline Rhabdomyolysis http//www.nlm.nih.gov/med
  • E-medicine Hypokalemia David Garth, MD,
  • American College of Rheumatologyhttp//www.rheuma

  • Kress JP, Pohlman AS, O'Connor MF, Hall JB. Daily
    interruption of sedative infusions in critically
    ill patients undergoing mechanical ventilation.
    New England Journal of Medicine. May 18 2000342
  • Phua, GC MacIntyre NR, Inhaled Corticosteriods
    in COPD, Respiratory Care July 2007 , vol 52 7
  • Critical illness polyneuropathy and myopathy
  • CDC pamphlet on CIM and CIPhttp//www.cdc.gov/nchs
  • Merck Manual Polyneuritis http//www.merck.com/mm
  • eMedicine Hypermagnesemia by Novello NA

  • Medline Plus nerve conduction studies
  • AMERICAN THORACIC SOCIETY Recommendations for
    Standardized Procedures for the Online and
    Offline Measurement of Exhaled Lower Respiratory
    Nitric Oxide and Nasal Nitric Oxide in Adults and
  • http//ajrccm.atsjournals.org/cgi/content/full/160

  • V Segredo, JE Caldwell, et al. Persistent
    paralysis in critically ill patients after
    long-term administration of vecuronium. NEJ Vol
    327524-528 8 August 20, 1992 http//content.nejm
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