diagnosis and investigations of obstructive sleep apnea

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Diagnosis and Investigat ions By Dr.Faizan Ali

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Diagnosis and Investigations

Diagnosis and InvestigationsBy Dr.Faizan Ali

SummaryPolysomnography (PSG)Mallampati scoreFriedman tongue scoreMullers maneuverAHIRDIEpworth Scale

Medical History

0-10Normal10-12Borderline12-24Abnormal

David P. White, M.D., Professor of Sleep Medicine at Harvard

Medical conditionsChronic obstructive pulmonary disease Restrictive lung diseasesMuscular dystrophyCardiac dysfunctionKyphoscoliosisHypothyroidismPituitary tumorsachondroplasia or Marfan Syndrome

Physical ExaminationOral ExaminationOthers

Body Mass Index = (Weight in Kilograms) / (Height in meters)2Neck circumference measured at a point 2 cm below the Adam's appleThe presence of retrognathia or micrognathia should be noted.

Oral ExaminationFocus on theLength of the soft palate (long palate is one that descends below the base of the tongue and cannot be directly seen).The size of the palatineTonsilsWidth of the palatal vault and dental arches.

Modified Mallampati scoreAssessed by asking the patient (in a sitting posture) to open his/her mouth and protrude the tongue as much as possible.Theanatomyof theoral cavityis visualized; specifically, whether the base of theuvula,faucial pillars(the arches in front of and behind the tonsils) andsoft palate are visible. Scoring may be done with or without phonation. Depending on whether the tongue is maximally protruded and/or the patient asked to phonate, the scoring may vary.

Original Mallampati Scoring:

Class 1: Facial pillars, soft palate and uvula could be visualized.

Class 2: Facial pillars and soft palate could be visualized, but uvula was masked by the base of the tongue.

Class 3: Only soft palate visualized.

Friedman tongue score

Friedman Palate Position I allows visualization of theentire uvula and tonsils/pillars.

Friedman Palate Position II allows visualization of theuvula but not the tonsils.Grading is based on the tongue in a neutral, natural position inside the mouth

Friedman Palate Position III allows visualization ofthe soft palate but not the uvula.Friedman Palate Position IV allows visualization ofthe hard palate only. Friedman tongue score

Friedman Tonsils score

Tonsils, size 1, are hidden within the pillars.

Tonsils, size 2, extend to the pillars.

Friedman Tonsils score

Tonsils, size 3, extend beyond the pillars but not to the midline.Tonsils, size 4, extend to the midline.

Clinical Staging For OSA pt

MICHAEL FRIEDMAN, MD, HANI IBRAHIM, MD, and LEE BASS, BS, Chicago, IllinoisOtolaryngologyHead and Neck Surgery July 2002

Muellers maneuverDiagnostic techniqueto detect airway narrowing. It is performed by attempting to inhale against pinched-off nose and closed mouth with a fiberoptic nasopharyngoscope in place. The resulting negative inspiratory pressure will cause the walls of the upper airway to collapse in the narrowed airway. A positive test is suggestive of OSAS.AHI is correlated positively with the Muellers maneuverEvaluation of Obstructive Sleep ApneaSyndrome by Computational Fluid DynamicsSomsak Sittitavornwong, Peter D. Waite, Alan M. Shih, Roy Koomullil, Yasushi Ito, Gary C. Cheng, and Deli Wang (Seminar 2009)

Flexible fiber optic scope

NASAL SPRAY TESTUsing topical nasal decongestant on alternate nights andcomparing severity of snoring and aponea

Airway AnalysisApnea-Hypopnea Indexcalculates sleep apnea severity based on the total number of complete cessations (apnea) and partial obstructions (hypopneas) of breathing per hour of sleep.

Respiratory disturbance index(RDI)used in reportingpolysomnography(sleep study) findings. Unlike the AHI, it also includesrespiratory-effort related arousals(RERAs).

RERAs are arousals fromsleepthat do not technically meet the definitions ofapneasorhypopneas, but do disrupt sleep. They are abrupt transitions from a deeper stage of sleep to a shallower.

Thegold standardfor measuring RERAs isesophageal manometry, as recommended by theAmerican Academy of Sleep Medicine(AASM). However, esophageal manometry is uncomfortable for patients and impractical to use in mostsleep centers.

High RDI was significantlycorrelatedwithexcessive daytime sleepiness, and that this correlation was stronger than that for the frequency ofoxygen saturationdecreases below 85%, but other studies have found only a weak correlation

RDIRDI = (RERAs + Hypopneas + apneas) X 60 / TST (in minutes).

Sleep Study

Multiple sleep latency test (MSLT)is performed to determine the level of daytime sleepiness in the patient.The time it takes for the patient to fall asleep during daytime naps is measured in the MSLT.Patients with excessive daytime sleepiness will have an abnormal MSLT and will have an average sleep latency during the MSLT of less than 5 to 8 minutes.

Maintenance of wakefulness test (MWT)measures a persons ability to stay awake. It consists of four nap periods each lasting 40 minutes in which the patient is asked to try to stay awake. Most normal persons without excessive sleepiness can remain awake during these naps. MWT is sensitive to sleep deprivation and the effects of circadian sleep-wake rhythmsPerformance vigilance testing Tests that involve repetitive tasks, such as driving simulators, which measure performance, attention, and alertness, can be used to assess excessive sleepiness.

OSLER TEST (Journal of sleep research 1997 A behavioral test to identify OSA L.S.BENNET,J.R.STRADLING R.J.O.DAVIES)

Pupillography

Several studies have shown that the diameter of the pupil is inversely and its variability over time positively related to subjective complaints of sleepiness.

The method has been used mainly in a clinical environment to assess EDS because it requires little co-operation and is hence very objective.

It has been shown to be sensitive to sleep restriction in healthy subjects .The method provides reliable results when comparing sequential tests in the same individual, but seems less suitable when comparing one subject with another or between different studies.

Polysomonography

PSGreference method for the diagnosis of patients with suspicion for SAHS and other non-respiratory sleep disorders (consistent recommendation, high quality of evidence).

Typically, during an overnight sleep study electrodes are placed to record brain activity, eye movements, and muscle activity as you sleep. The sleep technician may place other sensors on your chest or near the nose to record your breathing patterns.

Testing is usually performed in a private room beginning at your normal bedtime and you will be allowed to leave early the next morning. After your sleep data is analyzed, a detailed sleep report is sent to your family physician

TheAmerican Academy of Sleep Medicine(AASM) has classified sleep studies into 4 types.Type 1 is conventional PSG overseen by a technician in a sleep laboratory (with a minimum of 7 channels) Type 2 is PSG done with portable equipment and no technician present Type 3 is so-called RP, where breathing, thoracoabdominal effort and pulse-oximetry are recorded (with a total of 4-7 channels)Type 4 are super-simplified studies with a 1-2 channel apparatus (oximetry and/or breathing).

PSG should be done either at night or during the subject's usual sleep schedule, with a register of no less than 6.5 hours, including at least 3 hours of sleep.

PSG is a relatively expensive, laborious and technically complex technique that is not available at all centers, and due to the large demand of examinations it cannot be used in all patients.

ActigraphyA small, portable

movement detector typically using a piezoelectric accelerometer that generates voltages when motion is detected across three planes.

The data are stored in a self-contained memory chip which can collect data for up to 8 weeks and is then downloaded via wireless technology for analysis.

Does not measure

sleep, but sleep is inferred by relative quiescence andwakefulness is inferred by comparatively increasedmovement.

WatchPAT, (an at-home sleep apnea test)

-approved portable diagnostic device that uses the most innovative technology to ensure the accurate screening, detection, and follow-up of sleep apnea

Sleep diariesSleep and activity patterns over several days or weeks can be charted in a sleep diary, which may help uncover sleep disorders unsuspected from the patients history such as circadian sleep disorders and insufficient sleep syndrome. Entries can include bedtime; sleep latency; nighttime awakenings (frequency and duration);arising time; number, if any, of naps during the day; mealtimes; exercise times; and the use of medications, alcohol, and caffeine.

CEPHALOMETRIC METHODSThe size of the posterior airway space, The length of the soft palateThe distance from the mandible to the hyoid bone. These measurements are especially beneficial for decisions concerning surgical management.

Obstructive sleep apnoea: a cephalometric study. Part I. Cervico-craniofacial skeletal morphology VivatTangugsorn,OlavSkatvedt,OlafKrogstad,TorsteinLybergDOI:http://dx.doi.org/10.1093/ejo/17.1.4545-56First published online: 1 February 1995

A comprehensive cephalometric analysis of cervico-craniofacial skeletal morphology in 100 male patients with obstructive sleep apnoea (OSA) and 36 male controls was performed. The significant aberrations in the OSA group feature:shorter dimension of cranial base with slight counter-clockwise rotation and depression of clivus;shorter maxillary length with normal height;maxillo-mandibular retrognathia related to nasion perpendicular plane (NFH) despite normal angles of prognathism;47 per cent of the OSA group had mandibular retrognathia;increased anterior lower facial height and mandibular plane angle;reduced size of bony pharynx;inferiorly positioned hyoid bone at C4C6 level;deviated head posture with larger cranio-cervical angle.Cephalometric analysis is highly recommended in OSA patients as one of the most important tools in diagnosis and treatment planning.

Obstructive sleep apnoea: a cephalometric study. Part II. Uvulo-glossopharyngeal morphologyVivatTangugsorn,OlavSkatvedt,OlafKrogstad,TorsteinLybergDOI:http://dx.doi.org/10.1093/ejo/17.1.5757-67First published online: 1 February 1995

A comprehensive cephalometric analysis of uvulo-glossopharyngeal morphology in 100 patients with obstructive sleep apnoea (OSA) and 36 controls was performed. The aberrations in the OSA patients included:Increased length, thickness, and sagittal area of palate (PM-U; SPT; SPA;P