Publication of the Association of Polysomnographic Technologists • 2006, Volume 15, Number 4 • www.aptweb.orgPulse Transit Time: A UsefulClinical Tool?BY KIMBERLY TROTTER, M.A., RPSGT, ASSOCIATE EDITORWhat is Pulse Transit Time?Pulse Transit Time (PTT) is the time it takes <strong>for</strong> the arterial pulsepressure wave to travel from the aortic valve to a peripheral site 1 .It is usually measured from R wave on electrocardiogram (ECG) to thepulse wave arrival at the finger (using oximetric photopleythsmography).PTT has been shown to represent respiratory ef<strong>for</strong>t by detectingchanges in the blood pressure oscillations associated with pleural pressureswings (pulsus paradoxus) 2 . Blood pressure surges, detected byPTT, have been associated with micro-arousals as well 3 .HistoryPulse Transit Time (PTT) has been used since the 1970s as an indicatorof blood pressure changes 1 . Recently, PTT changes have been correlatedwith arousals 4,5 . Some research has gone as far as theorizingthat changes in PTT may denote arousals without the need <strong>for</strong> EEG 5 .Research ResultsMany studies include both adult and pediatric populations. Correlationsbetween electroencephalogram (EEG) arousals or sleep fragmentation,increased respiratory ef<strong>for</strong>t — esophageal pressure (Pes), thoracic, andabdominal respiratory ef<strong>for</strong>t — and PTT changes are shown.Pediatric StudiesThere have been many studies that show a correlation between Peschange and PTT change in children 4 , however, some of these studies discusslimitations in studying a pediatric population, including excessivemovement artifact.In some of these pediatric studies, PTT was shown to be slightly moresensitive to detecting respiratory events than Nasal Pressure (NP) alone.PTT is non-invasive, and does not disturb sleep or modify upper airwayas Pes has been shown to do 4,5,6 .Adult StudiesThe adult studies show similar results to pediatric studies. Again, NPwas shown to be just slightly less sensitive that PTT in detecting respiratoryevents, especially upper airway resistance syndrome (UARS) orrespiratory ef<strong>for</strong>t related arousals (RERAs).PTT is a desirable measurement <strong>for</strong> respiratory disturbancebecause it is non-invasive, and it is semi-quantitative. It has been shownto reveal micro-arousals and increased respiratory ef<strong>for</strong>t 2,7,8 .Should it be used in your lab?PTT can be a useful addition to NP or replacement <strong>for</strong> Pes, enablingmore sensitive monitoring <strong>for</strong> UARS/RERAs. There are PTT monitorsbuilt into some of the sleep monitoring systems, such as the RespironicsAlice 5. It is up to the technologist to let the data acquisition systemmanufacturers know that we are interested in studying PTT as a usefuladdition or tool <strong>for</strong> recognizing UARS/RERAs. ★References1. Smith, R. et al. Pulse Transit Time: an Appraisal ofPotential Clinical Applications. (1999). Thorax54;452-457.2. Pitson, D. et al. (1995). Use of Pulse Transit Timeas a Measure of Inspiratory Ef<strong>for</strong>t in Patients WithObstructive Sleep Apnea. Eu Respir J 8:1669-74.3. Pitson, D. et al. (1994). Changes in Pulse TransitTime and Pulse Rate as Markers of Arousal From Kimberly TrotterSleep in Normal Subjects. Clin Sci 87:269-73.4. Pepin, J. et al. (2005). Pulse Transit Time Improves Detection of Sleep Respiratory Eventsand Microarousals in Children. Chest 127;772-730.5. Katz, E. et al. (2003). Pulse Transit Time as a Measure of Arousal and Respiratory Ef<strong>for</strong>tin Children with Sleep-Disordered Breathing. Pediatr Res 53:580-588.6. Pagani, J. et al. (2003). Pulse Transit Time as a Measure of Inspiratory Ef<strong>for</strong>t in Children.Chest 124:1487-1493.7. Argod, J. et al. (2000). Comparison of Esophageal Pressure with Pulse Transit Time asa Measure of Respiratory Ef<strong>for</strong>t <strong>for</strong> Scoring Obstructive Non-apneic Respiratory Events.Am J Respir Crit Care Med July;162(1): 87-93.8. Poyares, D., et al. (2002). Arousal, EEG Spectral Power and Pulse Transit Time in UARSand Mild OSAS Subjects. Clin Neurophysiol Oct;113(10):1598-1606.About the AuthorKimberly Trotter, MA, RPSGT, is the <strong>Practice</strong> Manager <strong>for</strong> the University of Cali<strong>for</strong>nia at SanFrancisco (UCSF) Sleep Disorders Center, Pulmonary Function Lab and PulmonaryDepartment at Mount Zion Hospital. She is a past <strong>APT</strong> Board Member, Association <strong>for</strong> theStudy of Dreams <strong>for</strong>mer member, and a longtime sleep technologist. She is also an A2ZzzMagazine Associate Editor.Committee on Accreditation <strong>for</strong>Polysomnographic TechnologyEducation (CoA PSG)Is your Polysomnographic TechnologyTraining Program accredited? The CoAPSG is now accepting applications <strong>for</strong>accreditation from allied health educationprograms.CoA PSG accreditation is the gold standard<strong>for</strong> Sleep Technology educationalprograms and has several benefits:• Access to <strong>for</strong>mal and standardizededucational resources• Recognition of your program’s qualitycurriculum and instruction• Recognition by the Commission on Accreditation of Allied HealthEducation Programs (CAAHEP)• Prepares your students <strong>for</strong> the national credentialing examination• Recognition by professional societies, including the AmericanAcademy of Sleep Medicine, Association of PolysomnographicTechnologists and Board of Registered PolysomnographicTechnologistsVisit www.caahep.org/accredit.aspx?ID=obtainCredit <strong>for</strong> in<strong>for</strong>mationon the accreditation standards and guidelines or contact Dr. RichardRosenberg at (708) 492-0930 <strong>for</strong> more in<strong>for</strong>mation.18
Publication of the Association of Polysomnographic Technologists • 2006, Volume 15, Number 4 • www.aptweb.orgCognitive Changeson PSG TechniciansAfter Six Monthsof NocturnalShift WorkBY ROGERIO SANTOS DA SILVA, PH.D., RPSGTStudy per<strong>for</strong>med by: Francisco Gregorio de Oliveira, RogerioSantos da Silva, Lia Alves Simoes Matuzaki, Maria de LourdesLefevre Assumpcao, Fernanda Kelly Gimenes Bertini, RuthFerreira Santos, Sergio Tufik.Sleep Institute/AFIP; Sleep Medicine and Biology Discipline —Psychobiology Department — Federal University of Sao Paulo.AbstractObjectivesTo evaluate the effects of nocturnal shift work on cognitive functionof PSG technicians who had never worked during nocturnalshift be<strong>for</strong>e.MethodsThe per<strong>for</strong>mance of 18 PSG technicians, aged 20-35 years old,were evaluated be<strong>for</strong>e and six months after the beginning of nocturnalshift work. The schedule was 3-12 hours shifts. The followingneuropsychological tests battery was administered includingtests of general nonverbal intelligence, attention, verbal andnonverbal memory, and executive functions. The results were statisticallyanalyzed using Student’s t-test.ResultsSignificant differences between the per<strong>for</strong>mance of the PSGtechnicians be<strong>for</strong>e and after six months of nocturnal shift wereobserved, respectively: attention — increase of wrong answersin the Tolouse-Pieron Test (3.8+/-1.2 vs. 13.8+/-7.7)(p
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