12leadecg,transcutaneousmonitoring, andpulseoximetry · 3 indicaons"for"ecg" •...

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1 12 Lead ECG, Transcutaneous Monitoring, and Pulse Oximetry Craig Black, PhD, RRTNPS, FAARC 9. Perform Procedures a. 12 lead ECG b. Transcutaneous monitoring c. Pulse oximetry and capnography 10. Interpret procedure results a. 12lead ECG b. Transcutaneous monitoring c. Pulse oximetry and capnography

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Page 1: 12LeadECG,TranscutaneousMonitoring, andPulseOximetry · 3 Indicaons"for"ECG" • History"of"significantheartdisease,"especially"with"certain" signs"and"symptoms:" • Chestpain,"especially"radiang"to"arms"or"up"into"neck"

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12  Lead  ECG,  Transcutaneous  Monitoring,  and  Pulse  Oximetry  

   Craig  Black,  PhD,  RRT-­‐NPS,  FAARC  

     

 9.    Perform  Procedures      a.    12  lead  ECG      b.    Transcutaneous  monitoring      c.      Pulse  oximetry  and  capnography  

10.    Interpret  procedure  results      a.    12-­‐lead  ECG      b.    Transcutaneous  monitoring      c.      Pulse  oximetry  and  capnography  

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IntroducNon    •  The  12-­‐lead  ECG,  transcutaneous  monitoring,  pulse  oximetry,  and  capnography  all  yield  informaNon  which  directly  applies  to  the  paNent’s  respiratory  status.  

•  Must  always  be  placed  in  the  context  of  the  paNent’s  clinical  condiNon.  

•  No  subsNtute  for  direct  observaNon  of  paNent.  •  Always  treat  the  paNent,  not  the  “numbers.”  

12-­‐lead  ECG  •  Extremely  useful  non-­‐invasive  diagnosNc  tool  •  Recording  on  the  skin  of  the  electrical  acNvity  from  heart’s  conducNon  system  

•  PaTern  of  the  trace  used  to  determine  abnormaliNes  in  heart’s  conducNon  system  

•  Abnormal  paTerns  in  traces  correlated  to  specific  clinical  condiNons  

 

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IndicaNons  for  ECG  •  History  of  significant  heart  disease,  especially  with  certain  signs  and  symptoms:  •  Chest  pain,  especially  radiaNng  to  arms  or  up  into  neck  •  Shortness  of  breath  •  Dyspnea  (esp.  with  palpitaNons)  •  Diaphoresis  •  Syncope  •  Weakness  or  lethargy  

•  Used  to  screen  paNents  prior  to  surgery  or  medically  strenuous  or  risky  procedures.  

 

Performing  the  ECG  •  Wire  leads  from  ECG  machine  will  be  

labeled  to  designate  their  placement  on  the  body—criNcal  that  leads  be  placed  in  correct  posiNons  on  the  body  •  RA-­‐right  arm,  LA-­‐le^  arm,  RL-­‐right  leg,  LL-­‐

le^  leg  (usually  on  ankles)    •  Leads  V1—V6    called  precordial  and  are  

placed  on  chest  

•  PaNent  seated  or  lying  flat  

•  Eliminate  electrical  interference    

 

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ECG  InterpretaNon  •  ECG  printed  on  graph  paper  with  small  squares  (1mm)  and  large  squares  (5mm)  

•  ECG  has  number  of  waves  corresponding  to  movement  of  the  impulse  through  heart’s  conducNon  system.  

•  P  wave  •  QRS  complex        •  T  wave   P T

QRS

Analyzing  the  ECG  Trace  1.  Determine  the  heart  rate  (beats/minute)  2.  Examine  PR  interval  (number  of  small  boxes  between  start  of  P  and  start  of  QRS)—

should  be  <5  small  boxes  (0.2  sec)  3.  Examine  QRS  complex;  should  be  <2-­‐3  small  boxes  (0.12  sec)  4.  Examine  T  wave;  should  be  upright—inverted  suggests  ischemia  5.  Examine  ST  segment  (base  line  between  end  of  S  and  beginning  of  T  wave)—should  

be  flat  and  no  more  than  1mm  above  or  below  base  line  6.  Report  any  abnormaliNes  idenNfied  to  physician  

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Sinus  Bradycardia  

•  Normal  sinus  rhythm  except  for  rate  of  <60/min  •  May  be  a  result  of  intense  athleNc  condiNoning  •  Only  a  problem  if  it  results  in  clinical  symptoms  

•  Low  blood  pressure  •  FaNgue  •  Syncope  

Atrial  Fibrilla2on  •  Atrial  muscle  “quivers”  in  irregular  paTern  •  Baseline  electrical  acNvity  is  erraNc—no  true  P  waves  present  •  Clinically  

•  May  cause  decreased  cardiac  output  •  StagnaNon  of  flow  in  atria  may  result  in  thrombi—risk  of  pulmonary  embolism  

•  Treatment  

•  Drugs  to  stabilize  atrial  acNvity  (e.g.  digoxin,  beta-­‐blockers)  

•  Cardioversion  if  drugs  do  not  work  

•  AnNcoagulant  drugs  (e.g.  coumadin,  lovenox)  

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Atrial  Flu4er  •  Ectopic  focus  causes  rapid  atrial  depolarizaNon  (250-­‐350/min)  •  Extra  P-­‐waves  present  for  every  QRS  •  QRS  complex  normal  •  Not  considered  as  serious  as  atrial  fibrillaNon  since  it  normally  does  not  cause  

thrombi  due  to  stagnant  atrial  blood  flow  •  Treatment  

•  Same  as  atrial  fibrillaNon  except  anNcoagulants  normally  not  used  

Ventricular  Tachycardia  •  Characterized  by  wide,  bizarre  QRS  complexes  •  No  P-­‐wave  •  Ventricular  rate  of  100-­‐250/min  •  Is  considered  sustained  V-­‐tach  if  last  >30sec  •  Especially  serious  because  may  lead  to  ventricular  fibrillaNon  •  Treatment  

•  Cardioversion  •  Long-­‐term  anN-­‐arrhythmic  drugs  •  Implanted  automaNc,  internal  cardioverter/defibrillator  if  necessary  

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Ventricular  Fibrilla2on  •  Totally  erraNc,  disorganized  rhythm  paTern  •  Most  serious  of  all  arrhythmias  •  Ventricular  muscle  only  “quivers”  resulNng  in  no  cardiac  output  •  Fatal  if  more  normal  rhythm  is  not  restored  quickly  •  Treatment  

•  ACLS  protocol  for  cardiac  arrest—combinaNon  of  drugs  and  defibrillaNon  •  Survivors  

•  Long-­‐term  anN-­‐arrhythmic  drugs  •  Implanted  automaNc,  internal  cardioverter/defibrillator  •  Cardiac  catheterizaNon  with  placement  of  stents  or  coronary  artery  bypass  

surgery  

Transcutaneous  Monitoring  •  Provides  conNnuous  non-­‐invasive  es4mates  of  arterial  pO2/pCO2  via  sensor  held  on  

skin  by  adhesive  •  Sensor  enclosed  in  heaNng  element  that  warms  skin  

•  Heat  “arterializes”  capillary  blood  beneath  sensor  •  Increases  skin  permeability  to  O2/CO2    diffusion  •  Sensor  measures  transcutaneous  O2/CO2  (PtcO2/PtcCO2)  

•  Works  well  only  in  neonates  although  PtcCO2  monitoring  is  more  accurate  than  end-­‐Ndal  CO2  in  intubated  adults  

•  Readings  may  diverge  significantly  from  actual  PaO2/PaCO2  and  must  be  correlated  with  arterial  or  capillary  blood  gases  

•  Most  useful  as  a  way  to  “trend”  changes  in  PaO2/PaCO2  

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IndicaNons  for  Transcutaneous  Monitoring  

•  Need  for  conNnuous,  non-­‐invasive  monitoring  of  oxygenaNon  and  venNlaNon  (especially  criNcally  ill  infants)  

•  Need  to  quanNfy  in  real-­‐Nme  the  responses  to  diagnosNc  procedures  and  therapeuNc  intervenNons  (e.g.  venNlator  senng  changes)  

•  Monitoring  PaCO2  levels  in  adult  paNents  undergoing  general  anesthesia  (more  accurate  than  end-­‐Ndal)  

ContraindicaNons  

•  Very  fragile  skin  (extreme  prematurity)  •  Poor  peripheral  circulaNon  (e.g.  shock)  •  Skin  allergy  to  adhesive    

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Performing  Transcutaneous  Monitoring  

•  Sensor  is  calibrated  per  machine  instrucNons  •  HeaNng  element  temperature  set  (41oC  for  combined  PtcO2/PtcCO2  monitoring)  

•  Sensor  with  heaNng  element  applied  to  skin  •  Sensor  site  must  be  changed  every  2-­‐3  hours    •  A^er  sensor  is  moved,  new  readings  should  be  correlated  with  blood  gases    

InterpretaNon  of  PtcO2/PtcCO2  Readings  

•  Readings  must  be  allowed  to  stabilize  (10-­‐20min)  before  considered  valid  

•  If  a  reliable  esNmate  of  PaO2/PaCO2  is  desired,  PtcO2/PtcCO2  values  must  be  correlated  with  blood  gas  values  

•  Changes  in  readings  may  be  useful  for  trending  changes  in  PaO2/PaCO2  even  without  correlaNon  

•  Trending  can  be  helpful  in  determining  appropriate  Nming  for  blood  draws  

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Pulse  Oximetry  •  UNlizes  light  transmission  through  living  Nssue  to  determine  the  percent  

oxidized  hemoglobin  (saturaNon)  and  pulse  rate  •  Two  wavelengths  (660  and  940nm)  •  Changes  in  light  transmission  occurring  with  changes  in  Nssue  blood  flow  measured  to  determine  pulse  rate  

IndicaNons  for  Pulse  Oximetry  •  Need  to  monitor  arterial  oxyhemoglobin  saturaNon  levels  

•  Need  to  determine  the  response  of  arterial  oxyhemoglobin  saturaNon  to  various  diagnosNc  (e.g.  bronchoscopy)  or  therapeuNc  intervenNons  (e.g.  applicaNon  of  O2  delivery  device  to  paNent)  

•  Need  to  comply  with  regulaNons  of  regulatory  agencies  (e.g.  TJC  or  CMS)  

•  Is  considered  “Standard  of  Care”  

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ContraindicaNons  

•  Presence  of  significant  levels  of  CO  in  blood  •  Presence  of  significant  levels  of  MetHb  in  blood  

Performing  Pulse  Oximetry  •  Note  date,  Nme,  and  paNent  posiNon  and  acNvity  

•  Apply  sensor  probe  to  paNent    

•  Note  O2  status  (room  air,  O2  delivery  device,  flow/FIO2)  

•  Alarm  senngs  important  

•  Low  alarm  

•  88-­‐92%  for  term  infants,  children,  adults  

•  Use  insNtuNonal  protocol  for  premature  infants  

•  High  alarm  

•  Unnecessary  for  term  infants,  children,  adults    

•  Use  insNtuNonal  protocol  for  premature  infants  

•  Note  paNent  appearance  (e.g.  cyanosis,  capillary  refill)  

•  Note  reading  (value,  stability,  correlaNon  with  heart  rate  by  ECG  or  palpaNon)  

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InterpretaNon  of  Pulse  Oximetry  Results  Certain  factors  affect  the  validity  and  accuracy  of  pulse  

oximetry  results  Factor   Effect  Presence  of  CO  in  blood   Falsely  high  %HbO2    

Presence  of  metHb   Falsely  low  %HbO2  if  SaO2<85%  

Severe  anemia  (Hct<10%)   High  %HbO2  ,  but  low  CaO2      Dark  skin  pigmentaNon   Falsely  high  %HbO2  (3-­‐5%)  Poor  perfusion   Poor  signal,  unpredictable  (correlate  heart  

rate  with  ECG)  MoNon  arNfact   Poor  signal,  unpredictable  (correlate  heart  

rate  with  ECG)  MRI   Falsely  low  %HbO2    

Capnography  •  Graphic  representaNon  of  the  levels  of  CO2  in  gases  as  measured  by  a  capnograph  

•  Usually  applied  to  air  being  breathed  •  Modern  capnographs  can  display  changes  in  pCO2  throughout  individual  breaths  

•  Most  common  use  is  to  monitor  changes  in  levels  of  CO2  in  paNent  on  mechanical  venNlaNon  

•  Most  commonly  used  sensor  technology  is  infrared  absorpNon    

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IndicaNons  for  Capnography  •  EvaluaNon  of  exhaled  CO2  especially  end-­‐Ndal  levels  (PETCO2)  •  Monitoring  severity  of  pulmonary  disease  and  response  to  

therapeuNc  intervenNons  •  Determining  ETT  placement  in  trachea  (not  esophagus)  •  Monitoring  integrity  of  venNlator  circuit  including  arNficial  airway  •  Monitoring  effecNveness  of  mechanical  venNlaNon  •  Monitoring  inspired  CO2  when  it  is  being  therapeuNcally  

administered  •  Measurement  of  metabolic  rate  and/or  alveolar  venNlaNon    

Performing  Capnography  •  Two  types  of  capnographs—both  measure  PCO2  •  sidestream    •  mainstream  

•  Calibrate  analyzer    •  Apply  to  paNent  venNlator  circuit  •  Note  all  mechanical  venNlaNon  senngs  •  Note  paNent  respiratory/cardiovascular  status  

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InterpretaNon  of  Capnography  Results  •  Normal  capnogram  

•  PCO2  is  0  during  inspiraNon  •  PCO2  near  0  during  very  early  

exhalaNon  (A  on  diagram—Phase  I)  represenNng  emptying  of  dead  space  

•  PCO2  increases  (A  to  B—Phase  II)  as  alveolar  gas  mixes  with  dead  space  gas  

•  PCO2  level  plateaus  (B  to  C—Phase  III)  as  exhaled  gas  is  nearly  all  from  alveoli  

•  PCO2  at  highest  level  at  end  of  Phase  III  (Point  C—end  exhalaNon)  represenNng  alveolar  gas,  the  end-­‐Ndal  value  (PETCO2)  

•  PETCO2  normally  3-­‐5mm  Hg  less  than  PaCO2    

     

     

Time

40

30

20

10A

BC

pCO

2 (m

m H

g)

Certain  abnormal  capnogram  traces  are  indicaNve  of  specific  pulmonary  disease  processes  

 Abnormality   Pa4ern  seen  on  trace  

Rapid  increase  in  cardiac  output   Elevated  PETCO2  

Rapid  decrease  in  cardiac  output   Decreased  PETCO2  

HypervenNlaNon   Decreased  PETCO2  

HypovenNlaNon   Elevated  PETCO2    Massive  pulmonary  embolism   Decreased  PETCO2  

Circuit  disconnect   Trace  disappears  

V/Q  mismatch   Point  B  not  clearly  defined  and  Phase  III  shows  increased  slope