Sleep and Fatigue. Professor Jayant Phadke
REM vs Non-REM sleep. The amounts are equal at birth but by 6 months, REM: NREM = 3:7 and in the adult it is about 1:4.
NREM Sleep shows increased parasympathetic activity, with reduced HR and BP and increased cardiac electrical stability.
REM sleep has increased sympathetic tone with fluctuations in BP and HR.
The Recumbent Posture itself increases venous return and therefore increases cardiac filling pressure with potential for oedema in the upper airways and increased sympathetic activity.
Causes of Fatigue/Sleepiness: insufficient sleep, chronic pain, shift work, psychiatric illness, prescription drugs (beta blockers, narcotics, psychotropics, anticonvulsants etc). Others!
In Sleep Disordered breathing, polysomnography is vital to define the cause and its severity. Possible diagnoses include: Obstructive, Central or Mixed apneas, sleep-associated hypoventilation, Cheynes –Stoke breathing.
Apnea: “The complete interruption of naso-buccal airflow for at least 10 seconds”
The History may include: snoring, witnessed apnea, waking up gasping for air, excessive daytime sleepiness and early morning headaches.
Symptoms and signs of OSA: Cardiac Arrhythmias, Hypertension, Depression, Cognitive Impairment, Nocturia and Morning Headaches.
Sleep apnea increases cytokines, adhesion molecules and oxidative stress.
40 – 63% of CHF pts have apneas..
CPAP improves LVEF by about 8 – 10% and lowers BP and sympathetic activity
SDB (Sleep-Disordered Breathing) and Hypertension. 40 – 50 % of SDB have hypertension and vice-versa.
AN increased during sleep apnea – therefore apnea causes Nocturia
Treatment with CPAP reduces deaths in pts with CAD, reduces rate of acute coronary syndromes, hospitalisations and angioplasties (Milleron 2004)
Half MIs have SDB.
SDB is a cause of pulmonary hypertsion, paroxysmal atrial fibrillation.
SDB can induce brady-arrhythmias and even complete heart block (rarely even with a normal myocardium!
Note that home sleep studies make diagnosis a lot more accessible and cheaper and are accurate; they may well revolutionise the way we approach these problems. The diagnostic home study can be followed by Auto-CPAP at home and the data from that can be down-loaded to do the CPAP set-up for continued use.
Note that BMI is linearly related to Sleep Disturbance Index.
Ask all hypertensives about sleep disturbance.
Although compliance to CPAP is only 50%, it can be improved to 70 - 80% by trouble shooting on the phone in the first 4 weeks: 1. to address issues regarding mask and head-gear fittings. 2. Claustrophobia - desensitisation can help here. 3. Humidity can be controlled if this is a problem. 4. throat and/or mouth dryness often indicates mouth breathing, where a change from a nasal to full-face mask can be curative.
1. Drugs. E.g. mirtazepine, protryptiline
2. Oral appliances.
3. CPAP, BIPAP, VPAP
4. Surgical options (UPPP,nasal septum deviation correction, Hyoid suspension, Pillar procedure, maxillary/mandibular advancement.)
Restless Legs syndrom (restless Limbs syndrome)
Seen in 10 - 15% of the population and a potent cause of insomnia Sleep fragmentation and daytime sleepinessfrom the 70 -80% who have periodic limb movements.
diagnostic criteria include: sensory symptoms in the feet/legs (at times also in the arms), worse at rest, relieved to a variable degree by movement, worse at night. Check ferritin (if <50, iron may cure the symptom), Check for hypothyroidism, check for renal failure,check for neurological causes (neuropathy, spinal cord lesions, radiulopathy, Parkinsons)
Treatment: Dopa agonists such as ropinirole, pramipexole, levodopa/carbidopa are best options
Second line: clonazepam, opioids, gabpentin.
SSRIS or Tricyclics
Sodium Oxybate for severe symptoms
Psychostimulants for Daytime Somnolence
Non-benzodiazepine Hypnotics for sleep fragmentation.