Review Slides 2024 PSG 102 (PSG, rec parameters) Week 1 PDF

PSG 102 Foundations of Polysomnography Welcome Back Textbooks Essentials of Polysomnography: A training guide and reference for sleep technicians. William H. Spriggs. Polysomnography for the Sleep Technologist. Robertson, Marshall and Carno (2014)...

PSG 102 Foundations of Polysomnography Welcome Back Textbooks Essentials of Polysomnography: A training guide and reference for sleep technicians. William H. Spriggs. Polysomnography for the Sleep Technologist. Robertson, Marshall and Carno (2014) The AASM Manual for the Scoring of Sleep and Associated Events Vol 2.6. American Academy of Sleep Medicine (2020)  Keywords PSG Hook-up (electrodes/sensors, tools, PPE) The International 10-20 System Parameters to be Reported for PSG EEG EOG Chin EMG Impedance R&K 1968 AASM 2007, 2016, 2017, 2018, 2020, 2023 R&K 1968, AASM 2007  Differentiating Signal types Bioelectrical – Summed ionic flux generated by groups of cells or the polarity of one anatomical location relative to another on an organ – Measured by applying surface electrodes – EEG, EOG, ECG, EMG Transduced – Derived from a transducer that converts one form of energy to another (Mechanical energy to electrical) – Body position, nasal pressure airflow, snoring respiratory effort, movement Ancillary – Device that can process data on its own – Interfaced with the sleep recording system – End tidal, pulse oximeter carbon dioxide monitor Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier 10 Inc.  Bioelectrical Potentials. – AC voltages – EEG, EOG, EMG, EKG Transduced signals from sensors attached to the patient. – Usually supplied as DC voltages by sensors. – Respiratory effort belts, snoring, body position, SpO2 Signals derived from ancillary equipment. – PAP device – EtCO2 device  AC / DC Current Alternating Current (AC): An electric current which undergoes periodic reversals in the direction of its flow. The current supplied by power line in the USA is almost universally of this type and has a frequency of 60 Hz. AC amplifier is designed to process high- frequency signals. Direct Current (DC) channel: A channel derived from an external piece of diagnostic equipment such as a PAP device. AASM Sleep Facility Accreditation https://my.aasm.org/s/accreditation-verification?id=a2y4N0000038G0e  Sleep Facility Accreditation AASM sleep facility accreditation requires compliance with all of the rules, definitions, and notes in this manual. According to the AASM, rules specified to be recommended, acceptable, or optional are all acceptable methods for scoring. Based on the discretion of the clinician or investigator, a specific center or laboratory may use the acceptable rule in place of the recommended rule without any risk to accreditation. Optional rules may be followed in addition to the recommended and acceptable rules without any risk to accreditation. For further information please contact the accreditation department at the AASM ([email protected]). Next: Electrode and Sensor Application  Tools Scissors Ruler China Marker Alcohol Pads Tongue depressor Abrasive paste (Nu Prep) Cotton swabs EEG Conductive cream/paste (EC2, Ten 20) Gauzes Hair clips Medical Tapes Razor? Nail polish remover Posey tapes  PPE Mask Gloves Gowns Face Shields Hair cover Booties  Electrodes and Sensors Metal plate electrodes (EEG EOG Chin EMG) Snoring Sensors Snap-on ECG electrodes (ECG and Leg EMG) Respiratory Effort Belts x 2 Airflow Sensors x 2 (thermal and PT) Pulse Oximetry PSG Equipment (Analog)  Leads/Electrodes Gold cup Ear clip Snap on Needle EEG electrodes Snap-on electrodes  Electrode Types  Electroencephalography electrodes can be made from a variety of materials Common materials used - gold-plated silver, silver, and silver/silver chloride Never mix the use of electrodes made from different materials - artifact will result Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. 24  Electrodes  Standard polysomnography (PSG) recordings Gold-plated electrodes are the most common Silver/silver chloride electrodes needed adequate coating Over time will oxidize, re-chlorided on a regular basis Modern silver/silver chloride electrodes are sintered Silver chloride particles being baked into the silver Do not need regular chloride bathing Gold electrodes (silver with gold plate) Do not oxidize like silver/silver chloride electrodes Require less care Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. 25  Electrodes (Cont.)  Do not use if the electrode is: Chipped, cracked, or scratched direct current (DC) offset potential will be created can be seen as a baseline drift of the signal Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. 26  Electrode Types (Cont.)  Electrode cups Various styles Stamped  Thinner in design & bigger cup Casted  Thicker walls & smaller cup  More durable - don’t bend as easily Both are equally reliable for recording bio- electrical signal EEG cup electrodes used for adults are 10 mm in diameter, and pediatrics are 6 mm in diameter Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. 27  Electrode Wires  Also known as “leads” or lead wires  Attached to cup electrodes  Differences between types are small  When insulated with a thin Teflon® coating, are durable but tend to tangle more easily  When coated with a thicker insulation material, tend to tangle less readily but may not be as sturdy as the former Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. 28  Specific Use for Electrodes  Typically used to record EEG and EOG  Disposable most commonly used for convenience Disposable electrode patches are not appropriate for recording EEG data Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. 29  Cables, Connectors, and Jumpers  Each cable may have a different connector  Transducers Any device that converts one form of energy to another  Connectors for lead wires also vary depending on the type of system Common types (1.5-mm touch proof, keyhole, phone, RCA, RJ11, DIN) 1.5-mm touch proof  Most common  Also known as recessed-female connectors  They cannot be incorrectly mated  Required by the FDA to avoid accidental electrical shocks Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. 30  Connectors Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. 31  Cables, Connectors, and Jumpers (Cont.)  Jumpers Used for linked-ear reference or common reference Allows the signal to be referenced together to eliminate common artifacts May be required when a recorder has limited electrode input selection capabilities Especially helpful when trying to remove an ECG artifact from the EEG recording Artifact isolation can become difficult since an artifact from one input will spread across all “jumped” channels Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. 32 Thermistor, Thermocouple, Pressure transducer, and polyvinylidene fluoride (PVDF)  RIP and Piezo sensors Respiratory Inductive Plethysmography (RIP) Piezo sensor belts  Monitoring Respiratory Effort Respiratory inductive plethysmography Piezo technology Diaphragmatic and intercostal EMG Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier 35 Inc.  Monitoring Respiratory Effort (Cont.) Piezo electric crystal – Man-made or naturally occurring crystals that produce a charge – Repeated stress and release caused by breathing creates a sine wave pattern – Output not linear The waveform is only an approximation of the movement during respiration – Belts measure the tension where the crystal is located – Limitations Accuracy and readings when the patient moves Produce a phenomenon known as false paradoxing Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier 36 Inc.  Monitoring Respiratory Effort (Cont.) Diaphragmatic and/or intercostal EMG – Primarily used to differentiate between central and non-central respiratory events. – Reliability limited by proper electrode placement Difficult placing electrodes in the appropriate area Obese patients Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier 37 Inc.  Respiratory Inductance plethysmography (RIP) – Measures changes in cross-sectional area of the rib cage and abdominal areas during the breathing cycle – Belt with a wire woven or sewn along the entire length During respirations band is stretched and relaxed causing slight changes in the cross-sectional area that modify the magnetic field, resulting in a change in the frequency of the current Measured and converted to a voltage output that creates the waveform that is seen on the PSG Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier 38 Inc.  Respiratory Inductance plethysmography (RIP) (Cont.) – Linear signal – No electrical current passes through the patient, only a weak magnetic field is created – Sum channel – Does not produce false paradoxical breathing signals like piezo sensors – Calibrated or uncalibrated Calibrated - represents the actual volume of airflow, and can be used to create a flow-volume loop. Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier 39 Inc.  Sine wave pattern in RIP sensor belt Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier 40 Inc.  Sum Effort Channels Recorded using RIP technology Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier 41 Inc. Snoring sensor Snore Microphones and Sensors  Most widely used method of recording snoring in the sleep center  Records the vibrations or sound associated with snoring  Snore microphone Transducer - converts sound into a small analog voltage. Signal is interfaced with the recorder and displayed on an output channel. Electret, piezoelectric, and dynamic Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. 43  Snore microphone  Dynamic Moveable diaphragm that is displaced by the sound wave Movement of the diaphragm creates a voltage change Does not require a power source  Electret A dielectric material that is permanently electrically charged or polarized Forms the diaphragm and its distance from the plate causes a voltage to be induced Offers a wide frequency range Requires a power source Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. 44  Snore Microphones (Cont.)  Piezoelectric Respond to vibrations on the skin near the upper airway Are attached to the patient adjacent to the upper airway, which vibrates when snoring occurs. Designed with a raised center for increased vibration sensitivity Does not require a power source Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. 45 Body Position sensor  Recording patient body position Important parameter that is usually recorded on the sleep study report Monitored using video Manually recorded or automatically recorded using body sensors Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier 47 Inc.  Body Position Sensors Body position sensors can detect subtle changes in position Provide data based on gravity Must be oriented on the body correctly to achieve the correct output – Band firmly secured around the centerline of the chest or abdomen Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier 48 Inc. SpO2/SaO2 sensor Pulse oximeter Hypnogram EtCO2 SpO2 and EtCO2 Transcutaneous CO2  Audiovisual Monitoring and Recording Essential component of sleep study recording Video – Infrared light source is needed – Variety of video equipment available Fixed-focus system or pan-tilt zoom Audio – Most sleep centers have two audio monitoring systems 1. Patient-room audio – One-way communication, remains on at all times 2. Audio intercom system – Between control room and patient’s room Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier 55 Inc. Next: EEG  Electrode application  Site identification International 10-20 System for EEGs EOGs EMGs  Application and adherence techniques  Respiratory monitoring sensors Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. 58  Skin Preparation  Location identification  Clean and lightly abrade  Conducting agents  Impedance measurements Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier Inc. 59 AASM Technical Specifications for EEG  Derivation 1) The recording from a pair of electrodes in an EEG channel 2) EEG record obtained by this process AASM Scoring Manual International 10-20 International 10-20 Where are the T3 and T4? Where are the M1 and M2? The nasion (also known as bridge of the nose) is the midline bony depression between the eyes where the frontal and two nasal bones meet, just below the glabella. Mastoid Processes  Recording with surface electrodes (Cont.) Cleaning – Skin must be cleaned of all oils, sweat, and dead cells to allow the passage of electrical signals – Clean initially with alcohol to remove oils Abrading – Removing dead skin cells (Nu-prep® or Lemon-prep®) – Do not use alcohol after the skin is abraded – Conductive gel or paste is applied to the electrode either before or after it is affixed to the desired site Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier 73 Inc.  Recording with surface electrodes (Cont.) Impedance – The combination of resistance and capacitance Resistance - electrical barrier that is created by oil, sweat, and dead skin cells Capacitance - ability of a material to store an electrical charge – Impedance between a pair of electrodes should be balanced or the difference between them should be less than 2 kiloohms Copyright © 2014 by Mosby, Inc., an affiliate of Elsevier 74 Inc. Next: EOG The Polarity is Inverted in PSG. EOG The eye acts as a dipole in which the anterior pole is positive and the posterior pole is negative. If the eye moves from center position toward one of the two electrodes, this electrode "sees" the positive side of the retina and the opposite electrode "sees" the negative side of the retina. Consequently, a potential difference occurs between the electrodes. Assuming that the resting potential is constant, the recorded potential is a measure of the eye's position. Left gaze: the cornea approaches the electrode near the outer canthus of the left eye, resulting in a negative-trending change in the recorded potential difference. Right gaze: the cornea approaches the electrode near the inner canthus of the left eye, resulting in a positive-trending change in the recorded potential difference. Cornea: the transparent layer forming the front of the eye. Retina: a layer at the back of the eyeball containing cells that are sensitive to light and that trigger nerve impulses that pass via the optic nerve to the brain, where a visual image is formed. Next: Chin EMG Chin EMG Digasitc and Myohyoid Muscle