The paralyzed diaphragm - Hilary Klonin

The paralyzed diaphragm
Phrenic nerve pacing
Hilary Klonin with help from Dilys
Gore, Avery Medical

CASE-HISTORY
PATIENT TR 23 Year old professional dancer
• Party – Drink- Feels strange - Spiked
Leaves: Difficulty walking – collapses- picked up by EMS
• Admitted to CHBH - GBS
• Admitted to ICU – 48hrs later due to need for ventilation
-Mental function intact
-MRI - Cord oedema/ Inflammation from C1-T6
-Rx for GBS given
• 8 Weeks later no improvement- ventilator dependent
-Repeat MRI – Findings in keeping with “dead cord” C1-T6
-Nerve conduction studies – no function, -can’t pace diaphragm
- Neuros – irreverssible condition
CASE HISTORY cont’d
• Family counselling
-Canadian friends raising funds for chronic care
facility
- Human Rights Council involvement by
Canadian friends
• 6 months later: medical futility
- socioeconomic background not favorable
- Lives in informal settlement - Electricity
- Family and patient “ready”
• Withdrawal of therapy- death within 10 min

Indications for Diaphragm Pacing
Diaphragm motif

Duchenne 1870’s

•Andrew Ure,1818

Big Names
Glenn
Sarnoff
Avery

Neuromuscular physiology
Respiratory control center located in the
ventral aspects of pons and medulla
Efferent nerves travel down the
corticospinal tracts to synapse with lower
motor neurons at C3-C5
The lower motor neurons then stimulate
the diaphragm.

Diaphragm muscle fibers
Slow twitch (Type1) fatigue resistant
Fast twitch (Type 2) fatigable

Phrenic Nerve Pacing: Current Concepts
Jorge F. Velazco, Shekhar Ghamande and Salim Surani

Diagnosis
Suspect
Phrenic nerve electromyography
transdiaphragmatic pressure
Inspiratory/expiratory chest radiographs
are useful in evaluating patients with
diaphragm paralysis.
Sniff testing allows direct visualization of
diaphragm motion in response to a
conscious maneuver.

Sniff test

Indications for Diaphragm Pacing
Diaphragm Paralysis
• For those patients who have one or both diaphragms
paralyzed and have residual nerve function, a breathing
pacemaker can be considered.

Indications for Diaphragm Pacing
Quadriplegia
• Patients with very high cervical spine injuries involving C3
or higher
• Patients who have lost neurological control of respiration
due to brain stem injuries, strokes, or tumors
• Patients with injuries involving C4 need to pay particular
attention to nerve conduction as the majority of the phrenic
nerve originates at that level.
• Patients with injuries below C4 rarely require ventilatory
support
• Patients with damaged phrenic nerves may be able to
paced in conjunction with peripheral nerve grafts.

Indications for Diaphragm Pacing
Central Sleep Apnea
Congenital central hypoventilation syndrome, or CCHS,
is a rare disorder in which the patient does not have
automatic control of their breathing effort.
•Onset of central sleep apnea can occur later in life as a
result of any number of causes including stroke, brain
injury, and meningitis.
Age 3
• Patients with obstructive sleep apnea, without a central
component, are not appropriate candidates for a
breathing pacemaker.
Age 15

Patient selection
Patients with more limited degrees of
hypoventilation can be managed medically with
noninvasive ventilation, pulmonary
rehabilitation, weight loss, pulmonary toilet,
respiratory stimulants such as theophylline, and
bronchodilators.
Those with more severe degrees of
hypoventilation usually require some form of
mechanical ventilation, which may be
temporary.

Patient selection
High (C1- C3) spinal cord pathology
Congenital central hypoventilation syndrome (CCHS)
1/200,000 live births
Upper motor neuron dysfunction
Degenerative neuromuscular conditions

Avery Phrenic Nerve Pacer

Introduction to Diaphragm Pacing
The Mark IV Breathing Pacemaker System consists of surgically
implanted receivers and electrodes mated to an external transmitter
by antennas worn over the implanted receivers.
The external transmitter and antennas send radiofrequency (RF)
energy to the receivers implanted just under the skin.
The receivers then convert the radio waves into stimulating
pulses.
These pulses are sent down the electrodes to the phrenic nerves,
causing diaphragm contraction.
This contraction causes inhalation of air. When the pulse train
stops, the diaphragms relax and passive exhalation occurs.
Repetition of these series of pulses produces a normal breathing
pattern.

Breathing pacemakers are not
indicated for patients whose:
phrenic nerves have degenerated, or been
demylenated by a progressive disease.
diaphragms will not respond to electrical
stimulation (i.e., muscular dystrophy or an
eventrated diaphragm).
primary diagnosis involves compromised lung
function, such as COPD or emphysema.

CASE-HISTORY
PATIENT TR 23 Year old professional dancer
• Party – Drink- Feels strange - Spiked
Leaves: Difficulty walking – collapses- picked up by EMS
• Admitted to CHBH - GBS
• Admitted to ICU – 48hrs later due to need for ventilation
-Mental function intact
-MRI - Cord oedema/ Inflammation from C1-T6
-Rx for GBS given
• 8 Weeks later no improvement- ventilator dependent
-Repeat MRI – Findings in keeping with “dead cord” C1-T6
-Nerve conduction studies – no function, -can’t pace diaphragm
- Neuros – irreverssible condition
CASE HISTORY cont’d
• Family counselling
-Canadian friends raising funds for chronic care
facility
- Human Rights Council involvement by
Canadian friends
• 6 months later: medical futility
- socioeconomic background not favorable
- Lives in informal settlement - Electricity
- Family and patient “ready”
• Withdrawal of therapy- death within 10 min

Thoracoscopic

Nerve grafts
Intercostals to phrenic
Spinal accessory nerve to phrenic
Possibility of recovery

Diaphragmatic training
Pacing begins 4 – 6 wks post
implant
1-2hrs/day and slowly increased
over 3-4 months.
These patients may recover muscle
function with reconditioning.

Treatment Device
Phrenic Nerve Pacer
Mixture, some go back onto ventilator
at night
Mechanical Ventilation
Young children may have compliant
chest walls and move onto 24 hour
pacing as they get older

Advantages over PPV
Physiological Advantages
Negative pressure ventilation
• Lower infection rates due to the reduction in
suctioning, elimination of external humidifier
and ventilator circuits, and the potential
removal of the tracheostomy tube.

HEY requires all consultant staff
to be naked below the elbow

Advantages over PPV
Psychological Advantages
• Normal breathing and speech patterns
• Ease of eating and drinking
• Increased patient mobility
• Silent operation
• No face mask or other constrictive device
required.

Advantages over PPV
Financial Advantages
• Breathing pacemakers cost less than $1,000 per year in disposable supplies
(antennas, batteries, etc.) to operate.*
• They do not require the routine
maintenance or variety of disposable
supplies of a mechanical ventilator.
• The typical patient is able to
eliminate the rental of a backup
ventilator or other equipment which
can reduce monthly expenditures by
$1,500 - $2,500.
On average, a breathing pacemaker
will pay for itself in 3 years, and save
about $20,000 per year thereafter.
•Hirschfeld S, et al, Spinal Cord; pp 1-5, E-Pub
May 2008.
Avery
Information supplied by

Long term changes to diaphragm
or phrenic nerve
Electrical
Physiological
Histological

Possible complications
Injury to phrenic nerve
Infection
Atelectasis
Pneumonia
Pneumothorax
Vocal cord prolapse

Possible complications
Electrode failures or dislodgement
Broken or disconnected wires
Cannot use MRI
Muscle injury
Capnothorax
Mechanical failures

Mechanical Ventilation or Phrenic Nerve Stimulation for
Treatment of Spinal Cord Injury-Induced Respiratory
Insufficiency" Spinal Cord. May 2008, Vol. 46, No. 11, pp. 738-
742
64 SCI-RDD patients. 32 patients with functioning
phrenic nerves and diaphragm muscles , treated with
PNS
32 patients with destroyed phrenic nerves were
mechanically ventilated.
Incidence of respiratory infections, significantly
different
Quality of speech is significantly better with PNS
Increased employemnt
Costs paid off in one year

Patient feed back
A recent questionnaire sent to 550 quadriplegic patients
with Avery Breathing Pacemakers. 170 responders:
98% reported satisfaction with Avery and
their Breathing Pacemakers
96% report an improved quality of life
80% report pacing for 12 – 24 hours/day.
80% report improved mobility
70% report improved ability to speak

Probably something we should think about
10 patients have been implanted in South Africa
Memory sticks
Dilys@averybiomedical.com
Dilys Gore

PEDIATRIC AND NEONATAL, NIV MEETING
BARCELONA, SEPTEMBER 2013
I INTERNATIONAL
CONFERENCE
aulapediatria@hsjdbcn.org
Its good to talk
HILARY@LAMA.KAROO.CO.UK