The paralyzed diaphragm - Hilary Klonin

criticalcare.org.za

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

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