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SLEEP IN PATIENTS WITH CHRONIC RESPIRATORY DISEASES – A Wake Up Call for Chest Physicians
DR. J.C.SURIMD, DTCD, DNB, FNCCP
Consultant, Professor & HeadDept. of Pulmonary, Critical Care & Sleep
MedicineVardhman Mahavir Medical College &
Safdarjang Hospital, New Delhi
PHYSIOLOGY OF BREATHING
Respiratory center is under the influence of Behavioral inputs from cortical centers via
reticular activating system Chemical inputs from chemoreceptors
responding to PaO2, PaCO2 and pH Mechanoreceptors in the airway, lungs and
chest wall
Phillipson EA Am Rev Respir Dis 1978;118:909-939
Thorsten Schafer. Sleep Apnea. Prog Respir Res. Basel, Karger, 2006, vol 35 pp21-28
THE CENTRAL CONTROL OF BREATHING
Wakefulness (neural)Chemical (Hypoxic & Hypercapnic)Sensory afferent(Mechano receptors)
Motor OutputUpper airwaysDiaphragmIntercostal muscleAccessory muscles
Pattern Generator
Reticular formation
Respective network
RhythmGenerator
Effect of Sleep on Ventilation
Decreased neural output (i.e. drive to breath) Hypotonia of intercostal and accessory muscles
during REM Sleep Shift of ventilatory burden exclusively on the
diaphragm Increased upper airway resistance Decreased responsiveness to hypoxemia and
hypercapnia (i.e. chemosensitivity) Presence of SDB or OHS may further worsen
ventilation
SPECIAL EFFECTS OF REM SLEEP ON ACCESSORY & POSTURAL MUSCLES
REM sleep causes 1. Widespread cortical and medullary neuronal activity 2. Postural & accessory muscle atonia (including upper
airway)3. Intermittent disruption of diaphragm EMG activity.
The ventilatory consequences are 1. Greater dependence on diaphragmatic contraction2. Both VT and f are more variable than in NREM3. A more collapsible upper airway
REM HYPOVENTILATION IN COPD
Fletcher. JAP 1983;54:632-9
SLEEP-DISORDERED BREATHING SECONDARY TO POST-POLIO SYNDROME AND KYPHOSCOLIOSIS
C3/A2
O2/A1
ROC/A1
LOC/A2
Chin EMG
Right Anterior Tibialis
Left Anterior Tibialis
ECG
Nasal/oral Airflow
Respiratory Effort – Chest
Respiratory Effort – Abdomen
Oximetry
-100%
-- 50%
-- 0%
Stage 2
SaO2 = 88%
Stage 2 Stage 2
Muscle artifact in the LOC and ROC channels
HYPOVENTILATION IN REM SLEEP CAUSED BY LOSS OF ACCESSORY MUSCLE USE IN POST-POLIO PATIENT
C3/A2
O2/A1
ROC/A1
LOC/A2
Chin EMG
Right Anterior Tibialis
Left Anterior Tibialis
ECG
Nasal/oral Airflow
Respiratory Effort – Chest
Respiratory Effort – Abdomen
Oximetry
-100%
-- 50%
-- 0%
Stage REMStage REM Stage 1
SaO2 = 70%
Phasic twitches in leg EMG
Effect of Sleep on Respiratory Muscles
Inspiratory muscles
Awake (Healthy)
Awake (Resp. Disease)
NREM REM
Diaphragm Normal activity High activity Normal activity
Increased
Intercostal Low activity High activity Increased activity
Markedly reduced
Accessory Low activity High activity Normal activity
Markedly reduced
Airway Resistance
Upper airway resistance increases during sleep compared to wakefulness
Marked loss of tonic activity in tongue, pharyngeal, laryngeal and intercostal muscles in REM
Hudgel DW, Martin RJ. J Applied Physiol 1984:56:133-137
Lower airway patency may be compromised . Nocturnal broncho-contriction seen in 50% asthmatics compared to 8% normal subjects
Hetzel MR, Clark TJH. Thorax 1980;35:732-738
J Appl Physiol 1996;81:282-289
RESISTANCE AND VENTILATION DURING SLEEP
Mouth occlusion pressure (P 0.1) in five adults patients after Added Resistance
Ventilatory compensation to resistive loading occurs during NREM, but whether this compensation is as marked as during wakefulness is not clear
During REM, ventilatory compensation is markedly reduced Wakefulness & NREM before and after addition of
inspiratory resistance of 17 cm H2O/L/s
Iber C J Appl Physiol 1982;52:607-614
Hypoxic Ventilatory Response to Sleep
Douglas NJ Clin Chest Med 1985;6:563
In adult men the hypoxic ventilatory response in NREM sleep is 2/3rd that in wakefulness, falling to 1/3rd of level of wakefulness during REM
In adult women: no change in hypoxic response between wakefulness & NREM but response in REM is ½ that in other stages
Hypercapnic Ventilatory Response
Hypercapnic ventilatory response in adults drops during NREM to about ½ the level in wakefulness and falls further during REM to about 1/3 the level of wakefulness
Gender differences may exist
Douglas NJ Clin Chest Med 1985;6:563
Effect of Sleep Disorders
Obstructive Sleep Apnea Syndrome Sleep related Obesity Hypoventilation
Syndrome Both produce respiratory failure in sleep
Sleep
Cortical
Inputs
Respiratory
Center
sensitivity
Chemoreceptor &
Mechanoreceptor
sensitivity
Respiratory
Muscle
contractility
Lung mechanics:
Airflow resistance
FRC
V/Q relationships
Hypoventilation
Hypoxemia
Hypercapnia
EFFECTS OF SLEEP ON RESPIRATION
CLINICAL SEQUELAE OF HYPOVENTILATION AND DECREASED CHEMOSENSITIVITY
Increase in pCo2 by 2-8 mmHg
Decrease in pO2 by 3-10 mmHg or
2% decrease in SaO2
The drop in pO2 , Sao2 and rise in pCO2 is much
more in patients of chronic resp. diseases
Disruption of sleep architecture.
Effect of sleep related hypoventilation in health and disease
No significant harmful effect in
healthy individuals because of
typical shape of the ODC curve.
Significant hypoxia and
hypercapnia develops in patients
with chronic lung disease.
Baseline values of low PO2 and
high PCO2
Significant use of accessory
muscles during wakefulness.
Instability of the upper airways
PATHOGENESIS OF DIURNAL RESPIRATORY FAILURESleep
Nocturnal HypoventilationPo2 pCo2
Frequent Arousal
Sleep Disruption
Poor quality of sleep
Sleep deprivation
Decreased Ventilatory Drive to Co2
Bicarbonate retention from the kidney
Normalization of pH
Decreased respiratory drive
Multiple episodes of micro & macro sleep
Daytime Hypersomnolence
Elevated pCo2
Diurnal respiratory failure
Hypoventilation
CONSEQUENCES OF SLEEP RELATED HYPOXEMIA IN PATIENTS WITH RESPIRATORY DISEASES
Symptoms of disrupted sleep
Poor sleep
Restlessness during sleep
Tiredness during awakening, but no
sleepiness
Morning headaches
Effect of Nocturnal NIV
Prevents nocturnal hypoventilation Promotes HCO3 secretion from kidneys Normalizes sleep Reduces daytime hypersomnolence Improves chemosensitivity Respiratory muscle rest
SLEEP AND CHRONIC CHRONIC RESPIRATORY DISEASES
COPD ASTHMA NEUROMUSCULAR DISORDERS DPLDs
Sleep and Ventilation in COPD
Loss of enhanced awake central neural drive during sleep
Changes in chemo responsiveness to CO2 is accentuated in COPD patients
Hypoventilation mainly in REM sleep Altered V/Q mismatch Increased upper airway resistance
OXYGEN SATURATION DURING SLEEP IN A PATIENT WITH COPD
Douglas et al. 1979; lancet, I,1-4
Sleep Disordered Breathing and COPD
Co-existing sleep apnoea (overlap syndrome) in severe COPD may very from 10-20%
More than 10% of OSA patients have undiagnosed COPD
Chaouat A, Weitzenbaum E, Kreiger J Am J Respir Crit Care Med 1995; 151:82-86
Bradley TD J Am J Respir Crit care Med 1986; 134:920-924
Predictors of nocturnal desaturation in COPD patients
Nonobese patients with moderate to severe COPD with a H/O progressive decline in ABGs.
Hypercapnic patients with severe chronic bronchitis
Patients who experience oxyHb desaturation during exercise
Nocturnal O2 desaturation is associated with increased likelihood of CRF
INDICATIONS FOR EVALUATION OF SDB IN COPD
Moderate to severe daytime hypoxemia
Continued clinical deterioration despite the use of
oxygen therapy
Pulmonary and systemic hypertension
Heart failure
Symptoms suggestive of SDB in patients who
experience worsening hypercapnic failure despite
stable spirometry
Diagnostic Approach
Polysomnography
Oximetry
Portable devices
Treatment of COPD
Optimize medical management
Oxygen Therapy
Nocturnal NIV plus Oxygen Therapy
Effect of nocturnal NIV on Chronic Stable COPD meta-analysis
Meta-analysis of 4 RCTs
Peter J. Wijkstra. Chest 2003;124;337-343
Effect of nocturnal NIV on Chronic Stable COPD – Multicenter trial
Reduction in hospitalization
Improvement in dyspnea
Better health related quality of life
Reduction in health care cost
Sturani et al Eur Respir J 2002;20:529-38
Short-Term Effect of Controlled Instead of Assisted NIV in COPD
Dellweg et al. RESPIRATORY CARE • DECEMBER 2007 VOL 52 NO 12
Short-Term Effect of Controlled Instead of Assisted NIV in COPD
Dellweg. Et al RESPIRATORY CARE • DECEMBER 2007 VOL 52 NO 12
Short-Term Effect of Controlled Instead of Assisted NIV in COPD
Dellweg et al. RESPIRATORY CARE • DECEMBER 2007 VOL 52 NO 12
Weight Gain in Cachetic COPD Patients Receiving Noninvasive Positive-Pressure Ventilation
Budweiser et al. RESPIRATORY CARE • FEBRUARY 2006 VOL 51 NO 2
Change in body mass index after 6 months and 12 months of noninvasive positive-pressure ventilation, compared to baseline values. * p 0.05. † p 0.01
High-intensity Non-Invasive Positive Pressure Ventilation for stable Hypercapnic COPD
Windisch et al Int. J. Med. Sci. 2009, 6
IPAP (cmH2O) 28.0 ± 5.4 17(min) 42(max) EPAP) (cmH2O) 4.6 ± 1.3 2(min) 9(max)
Conclusions High-intensity NPPV is better tolerated by patients with severe chronic hypercapnic COPD and has been shown to be superior to the conventional and widely-used form of low-intensity NPPV in controlling nocturnal hypoventilation. High-intensity NPPV therefore offers a new promising therapeutic option for these patients.
Nocturnal mean6SD arterial carbon dioxide tension (Paco2) at baseline and at follow-up visits
Dreher et al. Thorax 2010;65:303e308
NIV in pulmonary rehabilitation of COPD patients
Thomas Ko¨hnlein et al. Respiratory Medicine (2009) 103, 1329e1336
Conclusion: nocturnal NIPPV is feasible and enhances the effects of pulmonary rehabilitation in advanced stage COPD.
Effect of NIV on stable COPD (Comparison of Costs)
Enrico M. Clini. Respiration 2009;77:44–50
Impact of sleep on patients with neuromuscular or chest wall disease
Specific diseases
The history of a particular disease may also be helpful in some cases.
Patients with polio who had initial involvement of respiratory, trunk, or bulbar muscles, particularly with associated scoliosis or vocal cord paralysis, are more likely to develop abnormalities of gas exchange during sleep.
Kyphoscoliosis, even in the absence of neuromuscular disease, is associated with nocturnal hypoventilation and obstructive sleep apnea.
Indications for a nighttime sleep study in patients with neuromuscular and chest wall disease
Symptoms of sleep disordered breathing
Arterial blood gases showing hypoventilation (PaCO2 >45 mmHg)
FVC <50 percent predicted Severely reduced Pimax Unexplained cor pulmonale
There are no randomised-controlled trials concerning the outcome of noninvasive ventilation in these conditions, but studies have shown an improved quality of life, physical activity and haemodynamics, normalisation of blood gases and slight improvement in other physiological measures, such as the vital capacity and maximal mouth pressures. Survival in chest wall disorders is 90% at 1 yr and 80% at 5 yrs, and similar figures have been obtained in nonprogressive neuromuscular conditions. If, however, the underlying disorder is deteriorating, particularly if it involves the bulbar muscles, it may limit survival despite the provision of adequate noninvasive ventilatory support.
Shneerson et al. Eur Respir J 2002; 20: 480–487
Kyphoscoliotic Ventilatory Insufficiency Effects of Long-term Nocturnal NIV
Blood Gas Levels and Lung Function Breathing Pattern and Respiratory Muscle Strength*
Cruz Gonzalez. Chest 2003;124;857-862
CONCLUSIONS
Lung diseases can present with a vast array of sleep related breathing abnormalities and symptoms
Sleep induced hypoventilation is the common cause of worsening failure
If night-time symptoms are present or suspected, overnight PSG with the determination of optimal treatment in a laboratory setting are recommended
Treatment of the underlying lung disease is an important first step
Nocturnal NIV can significantly improve daytime symptoms and ABGs
Recommended