Physiology of sleep breathing l.jpg
This presentation is the property of its rightful owner.
Sponsored Links
1 / 52

PHYSIOLOGY OF SLEEP & BREATHING. PowerPoint PPT Presentation


  • 272 Views
  • Uploaded on
  • Presentation posted in: General

PHYSIOLOGY OF SLEEP & BREATHING. John KOLBE Respiratory Services Green Lane Hospital, & Faculty of Health Science University of Auckland. .

Download Presentation

PHYSIOLOGY OF SLEEP & BREATHING.

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Physiology of sleep breathing l.jpg

PHYSIOLOGY OF SLEEP & BREATHING.

John KOLBE

Respiratory Services

Green Lane Hospital, &

Faculty of Health Science

University of Auckland.


Slide2 l.jpg

  • To die, to sleep; To sleep: perchance to dream: ay, there’s the rub; For in that sleep of death what dreams may come When we have shuffled off this mortal coil, Must give us pause.

William Shakespeare

“Hamlet”.


Slide4 l.jpg

  • What hath night to do with sleep?

John Milton

“Comus”: 1637.


Sleep oxford l.jpg

SLEEP (Oxford)

“Bodily function such as that which normally recurs for several hours per night in which the nervous system is inactive, eyes closed, postural muscles relaxed and consciousness nearly suspended.”


Sleep scientific l.jpg

SLEEP (Scientific)

Sustained quiescence in a species, specific state accompanied by reduced responsiveness to external stimuli.

Additionally in mammals;

- quick reversibility to the wakeful condition

- characteristic EEG changes

- ?spontaneous occurrence with endogenous

periodicity


Why do we sleep l.jpg

WHY DO WE SLEEP?

So we ain’t knackered, guv?


Function of sleep l.jpg

Function of Sleep.

  • ?

  • Mammals and birds have similar sleep physiology

  • Brain Metabolic Restoration

    • Remodelling of synaptic function

  • Energy Conservation

    • Reduction by only 10%

  • Enforced Immobility


Sleep wake cycle l.jpg

Sleep-Wake Cycle.

  • Push-Pull system

    • Circadian clock in suprachiasmic nucleus

    • Sleep drive/promotion- solitary tract nucleus, raphe nucleus,medial forebrain area

      • Related to duration of wakefulness and duration & quality of last sleep

    • Inhibition of reticular-activating system- alertness/wakefulness promotion:

    • Chemical influences

      • IL 1, TNFa, serotonin, adenosine (inhibits caffiene) promote sleep; PGE2 inhibits sleep


Stages of sleep l.jpg

STAGES OF SLEEP

Deeper Sleep

5 Stages

Non-REM Sleep

- Stage 1

- Stage 2

- Stage 3} Slow Wave Sleep

- Stage 4}

REM Sleep (motor activity is inhibited)


Stages of sleep17 l.jpg

Stages of Sleep.

  • Awake alpha rhythm

  • Non-REM

    • 1 alpha to theta

    • 2 sleep spindles,K complexes

    • 3

    • 4 SWS – thalamocortical

      burst activity ( delta waves)

      Fall in ventilation, CO, heart rate, blood pressure.


Sleep physiology l.jpg

SLEEP PHYSIOLOGY

REM and non-REM sleep alternate cyclically

REM sleep:

- 20-30min every 90-120 min

- increases later in night


Stages of sleep20 l.jpg

Stages of Sleep.

  • REM

    • Interaction between cholinergic activation and monoaminergic inhibition

    • cerebral metabolic activity

    • CNS excitation (dreaming)

    • Intermittent eye movements

    • inhibition of motor activity, loss of postural tone

    • Autonomic variability,cardio-respiratory instability


Sleep in newborn infants l.jpg

SLEEP IN NEWBORN & INFANTS

Enter sleep through REM (active sleep)

NREM-REM cycle, 50-60 min from birth

REM may be up to 50% of total

ECG patterns on non-REM emerge between 2-6 months and consolidate into sleep cycle

SWS becomes prominent when brain structure and function develop.


Sleep in children l.jpg

SLEEP IN CHILDREN.

  • SWS dominates

  • Awakening children in first SWS cycle may be difficult

  • Amount of SWS decreases progressively thru’ the second decade to account for 15-52% of sleep at end of teens.


Sleep architecture in young adults l.jpg

Sleep Architecture in Young Adults

Sleep is entered through non-REM

NREM and REM sleep alternate within period of 90-120 mins

SWS predominate in the first third of the night and linked to sleep initiation - approx 20 % of total

REM sleep predominates in the last third of the night and is linked to circadian temperature rhythms - 20-25% of total.


Sleep architecture in young adults24 l.jpg

SLEEP ARCHITECTURE IN YOUNG ADULTS

Wakefulness in sleep, <5% of night

Stage I2 - 5%

Stage II45 - 55%

Stage III3 - 8%

Stage IV10 - 15%

 NREM 75 - 80%

REM 20 - 25% in 4-6 episodes


Effect of age on sleep l.jpg

Effect of Age on Sleep

SWS fades with age (halves cf adolescents)

By 60 years no SWS in some men (loss of cortical synaptic density)

REM % of sleep is maintained in health old age (?relates to intellectual functioning)

Arousals increase with age

Marked variation


Structure of human sleep l.jpg

STRUCTURE OF HUMAN SLEEP

Amount favoured by an individual is highly variable (4-10 hours)

Amount needed is unclear, performance falls off <5-5.5 hours for most

Sleep deprivation leads to a “sleep debt” of SWS and REM

Proportions of each stage vary with age - significance unclear


Required duration of sleep l.jpg

Required Duration of Sleep.

  • Highly variable

  • 6.5-8.5 hrs

  • Sleep deprivation; major impact on

    • Cognition

    • Speed of performance


Sleep deprivation l.jpg

Sleep Deprivation.

  • Acute

    • Rebound increase in SWS

    • Followed by rebound increase in REM

  • Chronic

    • Disturbance of the usual sleep stage pattern during catch-up; bizarre phenomena like “sleep onset” REM.


Sleep deprivation disaster l.jpg

Sleep Deprivation = Disaster.

  • Chernobyl

  • Exxon Valdiz

  • Three Mile Island

  • Challenger Space Shuttle.


Structure of human sleep cont l.jpg

Structure of Human Sleep Cont.

Sleep patterns are very much habit and humans can adapt to bizarre sleep patterns and appear to function effectively

Shift workers have increased physical and psychological morbidity

Lack of SWS postulated to lead to loss of psychomotor performance

Lack of REM postulated to lead to irritability, mood swings etc.


Non rem sleep breathing l.jpg

NON-REM SLEEP & BREATHING

Respiratory drive

- stim effect of wakefulness

- chemosensitivity

Fluctuations in respiratory drive (in stage 1&2)

Non-chemical respiratory inputs are minimised.

Breathing regulated by metabolic respiratory control (in deeper stages, stable)

VE and slight PaCO2


Rem sleep breathing l.jpg

REM SLEEP & BREATHING

Irregular respiratory drive

Ventilatory response to chemical and mechanical stimuli may be transiently reduced or abolished

Short periods of (central) apnoea occur

Intercostal and accessory muscle activity

Generalised inhibition of skeletal muscle tone (including pharyngeal muscles)

 Thoraco-abdominal coupling


Breathing during sleep l.jpg

BREATHING DURING SLEEP

  • Clinical significance

  • Control of breathing

  • Sleep Physiology

  • Breathing during sleep

  • Patho-physiology of breathing during sleep


Physiologic impact of sleep on breathing l.jpg

PHYSIOLOGIC IMPACT OF SLEEP ON BREATHING

  • Very little in normals

  • Very important consequences in those with

    disturbances of respiratory structure or function

    eg-metabolic drive

    -diaphragmatic strength

    -intercostal and accessory muscle function activity ( imp in those with structurally small oropharynx)


Pharyngeal musculature l.jpg

Pharyngeal Musculature

•principally pharyngeal dilators/stabilisers

-genioglossus is predominantly an inspiratory phasic muscle

-tensor palatonic is a tonic postural muscle

•are “respiratory” muscles (output from CNS)

•respond to standard respiratory stimuli viz CO2, O2

•respond to negative pressure via superior laryngeal nerve


Sleep and pharyngeal muscle l.jpg

Sleep and Pharyngeal Muscle

•Inspiratory phasic muscles eg genioglossus, have near normal activity during sleep

•Tonic postural muscles (tensor palatini) activity

•Upper airway resistance increases during sleep in normals (x = 3) as a result of tonic muscle relaxation  snoring


Snoring l.jpg

Snoring

•Risk factors include males gender, obesity, alcohol /sedatives

•Not necessarily benign; associated with

- CAD risk

-Hypertension

- cerebrovascular risk

•In isolation is a poor marker for OSA (<50% of snorers suspected of OSA have AHI >10)

Not indication in itself to progress to sleep study unless other features present (eg witnessed apnoeas, hypersomnolence)


Slide42 l.jpg

  • Great eaters and great sleepers are incapable of doing anything that is great.

William Shakespeare

“Henry IV”


Osa pathophysiology l.jpg

OSA Pathophysiology

•UAW obstruction at level of tongue/palate

•Size of UAW lumen is a balance between

-tendency of pharynx to collapse during inspiration

-dilating forces (pharyngeal muscles)


Slide44 l.jpg

Mechanisms of Obstruction.

Airway Dilating

Muscles.

Obesity

Retrognathia

Sleep

Alcohol

Age

Pharynx


Sleep problems l.jpg

Sleep Problems.

  • Common

    • 10% have insomnia

    • 10-20% of partners annoyed by snoring

    • 2% of adults have a medical cause for pathological sleepiness

    • 1-4% of older males have OSAHS


Sleep history l.jpg

Sleep History.

  • I Insufficient sleep and insomnia

  • S Snoring and shift work

  • N Narcolepsy/cataplexy

  • O Obstructive apnea

  • R Refreshing sleep

  • E Excessive daytime sleepiness

  • D Drugs – sedatives & stimulants.


Sleep hygiene l.jpg

Sleep Hygiene.

  • Don’t have a fixed bedtime

  • Do have a fixed get up time

  • Do limit your activities in bed

  • Don’t stay in bed if fully awake

  • Don’t nap during the day

  • Do exercise


Sleep hygiene50 l.jpg

Sleep Hygiene.

  • Do have a bedtime ritual

  • Do banish clocks

  • Don’t use bed as a place to solve problems

  • Don’t worry if you do not sleep.


Slide51 l.jpg

  • What hath night to do with sleep?

John Milton

“Comus”: 1637.


  • Login