breathing , respiratory diseases, and mechanical ventilation

Anatomy and Physiology and Non-invasive Ventilatory Support

Cheryl NeedhamSr. Clinical Marketing Manager

breathing, •respiratory diseases, and mechanical ventilation

Confidential Sector, MMMM dd, yyyy, Reference

Conflict of Interest Disclosure(s) • ____I do not have any potential conflicts of interest to

disclose, • OR• __X_I wish to disclose the following potential conflicts of

interest:

• Type of Potential Conflict/Details of Potential Conflict• ____Grant/Research Support• ____Consultant• ____Speakers’ Bureaus• ____Financial support• __X_Other Employee of Philips Respironics


Objectives

• Review anatomy and physiology of the respiratory system• Discuss the etiology and pathophysiology for the following respiratory

disorders:– obstructive disorders– restrictive thoracic disorders– obesity hypoventilation – neuromuscular disorders

• Review treatment options for the respiratory management of selected diseases

Anatomy and Physiology

•


The Respiratory System:Breathing and Gas Exchange

Cerebrum

Brainstem

Spinal Cord

Mechanoreceptors

Chemoreceptors

Respiratory Muscles

Airway Vessels and Function

Gas Exchange

Controller

Effector

Result

Sensors/Feedback


Nervous System Divisions

• Nervous System– Central

• brain and spinal cord

– Peripheral• nerves transmitting

impulses to/from the brain

• Basic components– brain, spinal cord, nerves– neurons are basic cells

that carry impulses from one part of the body to another

Cerebrum

Brainstem

Spinal Cord

Controller


Central Nervous System (CNS)

• Factors that may impact breathing include:– drug administration– changes or damage to the

brain due to various diseases (ALS, dementia, stroke)

– loss or severing of motor neurons

ControllerCerebrum

Brainstem

Spinal Cord


Peripheral Nervous System (PNS)

• Further divided into 2 sub-systems

– Somatic (voluntary)– Autonomic (involuntary)

• Somatic System– controls skeletal muscles– voluntary movements

ControllerCerebrum

Brainstem

Spinal Cord

Relays signals to and from the brain!


Peripheral Nervous System (PNS)

• Autonomic system divided into 2 branches:

– Parasympathetic• conserves energy and

restores body’s resources for rest and digestion (breed or feed)

– Sympathetic• mobilizes person during

emergency or stress situations (fight or flight)

ControllerCerebrum

Brainstem

Spinal Cord


Respiratory Muscles and Rib Cage

• The diaphragm is the main muscle for respiration– primary muscle for inspiration

• There are also muscles found surrounding the rib cage– move the rib cage during

inspiration and exhalation

Effector Respiratory Muscles



Respiratory Muscles and Rib Cage

• Function during inspiration:– diaphragm contracts and moves

downward.– pressure is lower in the thoracic

cage causing air to come into the lungs

• Function on exhalation:– diaphragm relaxes and moves

upward compressing the lungs– pressure is higher in the lungs

causing air to move out of the lungs


Airway vessels and Function


Accessory Muscles - Inspiration

• Function to either raise the ribcage or stabilize it

• May be used for forced or deep breathing in normal conditions (i.e., exercise)

• Use of accessory muscles for resting inspiration is considered abnormal

– If used, patient may be having difficulty breathing

http://medicine.ucsd.edu/clinicalmed/lung.htm




Accessory Muscles - Expiration

• Expiration should require no effort due to the normal function of the lungs

• Any muscle usage for expiration is considered abnormal

• Accessory muscles of expiration include those found on the

– back, thorax, abdomen• Aids exhalation by pulling the

ribcage down or supporting it

http://www.emedicine.com/pmr/images/




Airway Vessel and Function

• The respiratory system is made up of 2 main sections:

– conducting airway– gas exchange area

• The conducting airway moves fresh gas from the atmosphere into the respiratory system

• The airway is made of a series of channels that lead the fresh gas to the gas exchange area:

– alveolar sacs




Center Court at Wimbledon vs. Your Lungs

Respiratory Muscles


Effector

What do they have in common?__________________________________

They have the same surface area!


Gas Exchange

• Goal of inspiration – move air to the area of the lung

that will allow gas exchange to occur• alveolar sac

• Pressure gradients determine if gas exchange occurs.

• Pressure gradient must exist– higher in the lungs, lower in the

blood

Result Gas Exchange


Gas Exchange

• In addition to fresh gas and movement of the pulmonary muscles, the alveolar units must have blood going past the alveolar sac

• The combination of fresh gas and blood allows for gas exchange to occur

– normal O2 levels for an adult: 80 – 100 mmHg

– normal PCO2 levels for an adult: 35 – 45 mmHg

Result Gas Exchange


Gas Exchange: Problems

• There can be many reasons why gas exchange does not occur, such as:– poor perfusion of the pulmonary system– destruction of the alveolar sacs– inability to move gas into the alveolar sacs

• decreased lung expansion• conduction problem with nervous system impulse• muscular weakness

– combination of factors

Result Gas Exchange

Respiratory Disorders in the Sleep Lab

•


Respiratory System Disorders

• Obstructive disorders– patient will have difficulty

exhaling used gases• Restrictive disorders

– patient will have difficulty inhaling fresh gases

• Obesity hypoventilation• Neuromuscular disorders


Obstructive - COPD

• A group of abnormal pulmonary conditions associated with cough, sputum production, dyspnea, airflow obstruction, and impaired gas exchange

– emphysema – chronic bronchitis– asthma

Chronic Bronchitis

Emphysema Asthma

COPD


Overlap Syndrome

• Introduced by Dr. David Flenley1

• Overlap Syndrome is used to describe the association of OSA and COPD

• Overlap syndrome is estimated in about 10 – 15% in COPD population2

• About 30% of COPD patients will experience nocturnal desaturation,

• Small percentage will have Overlap Syndrome

1 Flenley DC. Clin. Chest Med. 1985:6(4)651-666 2 McNicolas, W. Chest 2000:117:488-538


Impact of Sleep

• COPD patients may have more hypopneas vs. apneas

• Patients with moderate to severe COPD may have a marked response to REM sleep states with dramatic drop in oxygenation

• Patients may have nocturnal desaturation without having daytime desaturation

• Factors that will impact extent of Overlap Syndrome– Hypoventilation– Desaturation during NREM & REM sleep– Alterations in ventilation vs. perfusion with body position– Daytime PaO2 and PaCO2


Relationship between OSA and COPD: Sleep Heart Health Study

• Evaluated polysomnography and spirometry results of 5954 patients enrolled in SHHS.

• Aim of study: – evaluate the association between OSA and COPD– evaluate the impact of desaturation on patients with COPD both

with and without OSA• A total of 1132 studied had mild obstructive airway disease

Sanders, et al AJRCCM 2003:7 - 14


Restrictive Thoracic Disorders

• Neuromuscular disease– Amyotrophic Lateral Sclerosis (ALS)– Guillain-Barre’ (GB) and Myasthenia

Gravis (MG)• Obesity hypoventilation• Chest wall deformities

– skeletal disorders– kyphosis/scoliosis

• All forms lead to hypoventilation of the lung regions and atelectasis

My character was based on a friend of

Walt Disney’s who had MG


Amyotrophic Lateral Sclerosis (ALS): Etiology

• A progressive degenerative disease that affects nerve cells in the brain and the spinal cord

• When the motor neurons die, the ability of the brain to initiate and control muscle movement is lost

– voluntary muscle action is progressively lost

ALS is often referred to as "Lou Gehrig's Disease"


Etiology and Anatomical Changes

•Weakened bulbar muscles can cause closing of the airway

•Nerve and muscle functions relax during sleep causing under- ventilation

– complaints of morning headaches, lethargy, and shortness of breath (SOB)

Living with ALS: Adapting to Breathing Changes, 1997, ALS Assoc.


Obesity Hypoventilation Syndrome (OHS): Etiology

• Absence of significant lung or respiratory disease1

• May result from both a defect in the brain's control over breathing and excessive weight against the chest wall

– makes it hard for a person to take a deep breath

– inefficient breathing leads to lower PO2 levels and higher PCO2

levels in the blood when awake

May be referred to as “Pickwickian Syndrome”

Banerjee, D. and et al. Chest 2007;131;1678-1684


Signs and Symptoms

• Extreme obesity• Often exhibit the following:

– tired due to sleep loss– poor sleep quality– chronic hypoxia

• Difficulty breathing when supine• OSA plus OHS may cause

severe O2 desaturation during sleep



Complex apnea and central apnea

Treatment Options

•


Sleep Disordered Breathing

OSA Central Hypoventilation

CPAPBiPAP

Volume Assured Pressure Support

Noninvasive Ventilation

Confidential Sector, MMMM dd, yyyy, Reference 34

Bilevel patient types


Bi-level S/T mode

• Bi-level support with Spontaneous and Timed mode activated• This mode is used with patients that require

– Time rate from the device to support their inconsistent respiratory pattern

– Pressure support to augment their tidal volume when the device provides a breath to the patient

– Ability to receivespontaneously initiated breaths or timed back up breaths from the device


Bi-level Devices provide pressure with a variable volume delivery

VT

P

300 cc455 cc 450 cc

12 cm H2O 12 cm H2O 12 cm H2O

Over time - static pressure therapy with variable volume delivery may not provide adequate therapeutic support for progressive disease states patient conditions:• ALS• Overlap Syndrome (COPD + OSA)• OHS (obesity hypoventilation syndrome)

Bi-level Pressure Delivery

600 cc


Consensus Conference

“…in patients with neuromuscular disease … recent reviews have cited the advantages of pressure targeted devices for comfort and their ability to compensate for leaks.” “pressure targeted systems are not able to guarantee a minimum minute ventilation.”

Source: Consensus Conference Chest 1999: “Clinical Indications for Noninvasive Positive Pressure Ventilation in Chronic Respiratory Failure Due to Restrictive Lung Disease, COPD, and Nocturnal Hypoventilation”


Bi-level with Volume Assurance

• Acts primarily as a bi-level pressure support device but is able to provide a constant tidal volume.

• Automatically adjusts the pressure support level to maintain a consistent tidal volume

– Pressure will automatically increase or decrease to maintain set tidal volume


• Automatically adjusts the pressure support level to maintain a consistent tidal volume

• IPAP will automatically increase or decrease

Bi-level with Volume Assurance


Volume Assurance with PS is NOT recommended for patients with periodic breathing • Treatment of periodic breathing requires a variable breath by breath

response system so the patients PaCO2 stabilizes quickly– Prevents overshooting or undershooting the PaCO2 breath by

breath– Does not augment the patients tidal volume consistently

• Volume Assurance with PS does not have a quick variable response to changes in tidal volume.

– It is designed to adjust and maintain a constant tidal volume with each breath over time.

– This benefit often seen with patients who have slow declines in their ventilatory conditions.


Advanced NIV Titration Goals

Titration Goals:

Airway management, stabilize breathing patterns

monitoring patient’s response

optimal therapy efficacy and adherence

for

and

by

adjusting user set parameters if needed


Sleep Disordered Breathing

OSA Central Hypoventilation

CPAPBiPAP

Auto Servo Ventilation

Noninvasive Ventilation

Confidential Sector, MMMM dd, yyyy, Reference 45

Servo ventilation patient types


Treatment options for complex sleep apnea

• CPAP + time on therapy to reset chemoreceptors for patient1

– Must qualify with RDI > 5 with symptoms of OSA or RDI > 15 without symptoms 2

– 30-day trial on CPAP then follow up with patient on excessive daytime sleepiness, if improved keep on CPAP

• No improvement in daytime sleepiness after 30 days, try alternatives – Medications + CPAP – Auto Servo Ventilation– Bi-Level therapy with backup rate

• RAD policy for complex sleep apnea

46

1 Dernaika T et.al; Chest 2006 s;130(4)129

2 Adult Sleep Apnea Task Force, AASM, ; Journal of Clinical Sleep Medicine 2009; 5(3)


Servo Ventilation

• Treatment for complicated breathing patterns such as:

– Central apnea– Complex apnea– Periodic breathing such as CSR

• Provides non-invasive ventilatory support to treat adult patients with OSA and respiratory insufficiency caused by central and/or mixed apneas and periodic breathing.

47


Complex sleep apnea patients may challenge even the most experienced, skilled sleep technologist!

• Complex sleep apnea patients have multiple pathologies each requiring the attention of the technologist

• Helpful hints for complex sleep apnea titrations

– Obstructive apneas, obstructive hypopneas, central apneas, hypopneas, RERAs and periodic breathing may all be present intermittently throughout the sleep period

– Making the patients 100% normal may not be a realistic goal

– Optimizing therapy within a range the patients tolerates, will be compliant with and makes them much better than they were is an achievable goal

– Patience is key to successful titrations

– If a change is needed and made, Watch, Wait, Observe and Think before making any other adjustments


Why not use auto servo ventilation for a neuromuscular diseased patient?

• Would continually reset it’s baseline, worsening the hypoventilation

• Normal target continues to decrease – continues to under ventilate patient as the night progresses

Time

Ventilation


Why not use volume assured pressure support for Periodic Breathing such as Cheyne Stokes?•

– Volume assurance with PS does not respond fast enough – event would be over before reaching needed pressure

– Length of event vs. time of response


Pearls

51

Complex physiology and pathology makes many patients difficult to treat.

They are a moving target.

Many times, making them BETTER THAN THEY WERE on the titration night IS a success!

In contrast to uncomplicated OSA patients titrated on CPAP, the titration

doesn’t END on the titration night. It is just

the beginning!


breathing , respiratory diseases, and mechanical ventilation

Documents