20 patient monitoring


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20 patient monitoring

  1. 1. Patient Monitoring 23 November 2008 Elvin Cruz, MD, MS Med ETT Anesthesiologist Roizen: Essence of Anesthesia Practice Stoelting, Miller: Basics of Anesthesia Morgan, Mikhail: Anesthesiology Faust: Anesthesiology Review
  2. 2. Monitoring <ul><li>Why monitor vital signs? </li></ul><ul><li>ASA standard of care on monitoring under anesthesia </li></ul><ul><li>NIBP </li></ul><ul><li>ECG </li></ul><ul><li>Pulse oximetry </li></ul><ul><li>Capnography </li></ul><ul><li>Arterial blood pressure </li></ul>
  3. 3. Monitoring <ul><li>Data collection </li></ul><ul><li>Early warning of adverse changes or trends </li></ul><ul><li>Response to therapeutic interventions </li></ul><ul><li>Reflect proper functioning of other equipment </li></ul><ul><li>The most important monitor is </li></ul><ul><ul><li>YOU, the care provider </li></ul></ul><ul><ul><li>Remain vigilant, integrate monitor information into patient care </li></ul></ul>
  4. 4. ASA Standards for Basic Anesthesia Monitoring <ul><li>Applies to ALL anesthetics (GA, MAC, Regional) </li></ul><ul><li>Intended to encourage quality patient care </li></ul><ul><li>Can be exceeded at any time based on judgment </li></ul><ul><li>Not intended for OB/pain management </li></ul>
  5. 5. <ul><li>STANDARD I </li></ul><ul><ul><li>Qualified anesthesia personnel continuously present </li></ul></ul><ul><li>STANDARD II: Continually evaluate </li></ul><ul><ul><li>Oxygenation </li></ul></ul><ul><ul><ul><li>Inspired gas: O 2 analyzer with low O 2 alarm* </li></ul></ul></ul><ul><ul><ul><li>Blood oxygenation: POx, color assessment* </li></ul></ul></ul><ul><ul><li>Ventilation </li></ul></ul><ul><ul><ul><li>Chest excursion, Reservoir breathing bag observation, auscultation </li></ul></ul></ul><ul><ul><ul><li>Quantitative ETCO 2 </li></ul></ul></ul><ul><ul><ul><li>Expired volume quantification* </li></ul></ul></ul><ul><ul><ul><li>ETT/LMA position verified with clinical assessment + ETCO 2 </li></ul></ul></ul><ul><ul><ul><li>Disconnect alarm when using PPV </li></ul></ul></ul>ASA Standards for Basic Anesthesia Monitoring <ul><li>Can be waived under extenuating circumstances, document in the medical record record the reason </li></ul>
  6. 6. ASA Standards for Basic Anesthesia Monitoring <ul><li>Cont. STANDARD II: Continually evaluate </li></ul><ul><ul><li>Circulation </li></ul></ul><ul><ul><ul><li>Continuous ECG* </li></ul></ul></ul><ul><ul><ul><li>NIBP & HR at least every 5 minutes* </li></ul></ul></ul><ul><ul><ul><li>With GA: At least one of these </li></ul></ul></ul><ul><ul><ul><ul><li>Palpation of pulse </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Heart sounds auscultation </li></ul></ul></ul></ul><ul><ul><ul><ul><li>IABP </li></ul></ul></ul></ul><ul><ul><ul><ul><li>POx </li></ul></ul></ul></ul><ul><ul><ul><ul><li>US peripheral pulse monitor </li></ul></ul></ul></ul><ul><ul><li>Temperature </li></ul></ul><ul><ul><ul><li>Monitor when clinically significant changes anticipated/expected </li></ul></ul></ul><ul><li>Can be waived under extenuating circumstances, document in the medical record record the reason </li></ul>
  7. 7. Automated oscillometric NIBP monitor <ul><li>Non-invasive, automated </li></ul><ul><li>Air pump with deflation valve to control cuff pressure </li></ul><ul><li>Transducer measures cuff pressure and pressure oscillations within the cuff </li></ul><ul><li>Systolic and MAP correlate well with invasive BP measurements, but diastolic usually 10 mmHg higher with this method </li></ul>
  8. 8. Automated oscillometric NIBP monitor From: http://egems.gehealthcare.com/geCommunity/monitor/faq_bedside/nbp_faq.jsp Threshold                                                                                
  9. 9. <ul><li>Size of cuff influences measurement of BP </li></ul><ul><ul><li>Too small a cuff => Falsely increased BP </li></ul></ul><ul><ul><li>Too large a cuff => Falsely decreased BP </li></ul></ul><ul><li>Loosely wrapped cuff => Falsely increased BP </li></ul><ul><li>Too frequent measurement or wrapped too tight => distal edema </li></ul><ul><li>To avoid nerve damage </li></ul><ul><ul><li>Avoid applying cuff on bony prominences </li></ul></ul><ul><ul><li>Avoid applying cuff across joints </li></ul></ul><ul><li>Select maximum cycle time consistent with safe monitoring </li></ul><ul><li>Record cuff location and cycle time </li></ul><ul><li>Keep ALARMS enabled </li></ul>Automated NIBP monitor complications
  10. 10. ECG <ul><li>Continuous visual display </li></ul><ul><li>Monitors cardiac electrical activities only, it does not measure heart function </li></ul><ul><li>Early detection of </li></ul><ul><ul><li>Dysrhythmias: </li></ul></ul><ul><ul><ul><li>Lead II </li></ul></ul></ul><ul><ul><li>Myocardial ischemia: </li></ul></ul><ul><ul><ul><li>Lead V5 </li></ul></ul></ul><ul><ul><li>Electrolyte changes </li></ul></ul><ul><li>Allow calculation of HR </li></ul>
  11. 11. ECG <ul><li>Normal values (adults) : </li></ul><ul><ul><li>60 < Pulse < 100 </li></ul></ul><ul><ul><li>PR interval 0.12 – 0.20 sec </li></ul></ul><ul><ul><li>QRS duration 0.06 – 0.10 sec </li></ul></ul><ul><ul><li>QT interval <= 0.40 sec </li></ul></ul><ul><li>Pulse >100: Tachycardia </li></ul><ul><li>Pulse <60: Bradycardia </li></ul>R-R interval
  12. 12. Normal Sinus rhythm HR ~ 85 bpm Pulse Rate estimation HR = 1500/#small boxes in R-R interval HR = 300/#large boxes in R-R interval
  13. 13. Sinus Tachycardia, HR ~ 135 Sinus Bradycardia, HR ~ 52
  14. 14. Monophasic VT (Ventricular Tachycardia), HR ~ 185 VFib (Ventricular Fibrillation)
  15. 15. Asystole Check pulse Check connections Verify other leads Multifocal PVCs (Premature Ventricular Contractions)
  16. 16. Pulse Oximetry <ul><li>Practical, non-invasive, reliable monitoring of SpO 2 as a reflection of SaO 2 </li></ul><ul><li>Early warning of arterial hypoxemia </li></ul><ul><li> the need for PaO 2 determinations (ABGs) </li></ul><ul><li>LED measures absorption of specific wavelengths of light during arterial pulsations </li></ul><ul><li>Computer calculates SpO 2 </li></ul><ul><li>SpO 2 > 90% correlates with PaO 2 > 60 mmHg </li></ul><ul><li>Alarms for HR, SpO 2 values </li></ul><ul><li>Acceptable in most cases: 92 <= SpO 2 <= 100 </li></ul><ul><li>O 2 supplementation likely needed for SpO 2 < 93 </li></ul>                                                                         
  17. 17. Pulse oximetry <ul><li>Oxygenated Hgb (HbO 2 ) and deoxygenatred Hgb (Hb) have different optical spectra in the 500-1000 nm wavelength range </li></ul>
  18. 18. Pulse oximetry <ul><li>How to use: </li></ul><ul><ul><li>Prefer site without arterial catheter, BP cuff, or IV line </li></ul></ul><ul><ul><li>Align light source and photodetector </li></ul></ul><ul><ul><li>Move site of reusable sensor every 4 hours </li></ul></ul><ul><ul><li>Check adhesive sensor site for skin integrity every 8 hours </li></ul></ul><ul><ul><li>Reusable sensors thoroughly cleaned between patients </li></ul></ul><ul><li>Advantages </li></ul><ul><ul><li>Continuous monitor </li></ul></ul><ul><ul><li>Non-invasive </li></ul></ul><ul><ul><li>Early warning of arterial hypoxemia </li></ul></ul><ul><ul><li>Monitor pulse rate </li></ul></ul><ul><ul><li>Decreased need for SaO2 determinations (blood gas) </li></ul></ul>
  19. 19. Pulse Oximetry Limitations <ul><li>Decreased vascular pulsations (Low perfusion states) </li></ul><ul><ul><li>Hypotension </li></ul></ul><ul><ul><li>Hypothermia </li></ul></ul><ul><ul><li>Vasoconstriction </li></ul></ul><ul><li>Motion artifacts </li></ul><ul><ul><li>Shivering </li></ul></ul><ul><ul><li>Agitated </li></ul></ul><ul><li>Light interference </li></ul><ul><ul><li>Ambient light </li></ul></ul><ul><ul><li>Radiant warmers </li></ul></ul><ul><li>Nail polish (especially blue, green, brown) </li></ul>
  20. 20. Pulse Oximetry Limitations <ul><li>Dysfunctional hemoglobins can be interpreted as Oxyhemoglobin by the pulse oximeter </li></ul><ul><ul><li>COHgb interpreted as HbO 2 => Falsely high SpO 2 </li></ul></ul><ul><ul><li>MethHgb biases SpO 2 reading towards 85% </li></ul></ul><ul><ul><li>FetalHgb has little influence in SpO 2 </li></ul></ul><ul><li>Errors in data interpretation </li></ul><ul><li>Skin burns in MRI </li></ul><ul><li>TR results in venous pulsations => Falsely low SpO2, specially with ear probes </li></ul>
  21. 21. Pulse Oximetry Limitations <ul><li>Values accurate from 70-100%. Any number below 70% is an extrapolation and not very accurate (although less than 70%). </li></ul>SpO 2 number likely to be inaccurate
  22. 22. Capnography <ul><li>Continuous measurement of patient’s inhaled and exhaled [CO 2 ] </li></ul><ul><li>Waveform display more informative than the value </li></ul><ul><li>Useful for evaluation of </li></ul><ul><ul><li>Esophageal intubation </li></ul></ul><ul><ul><li>Disconnect in breathing circuit </li></ul></ul><ul><ul><li>Rebreathing of CO 2 </li></ul></ul><ul><ul><li>Cardiac arrest </li></ul></ul><ul><ul><li>Malignant Hyperthermia / Thyroid storm </li></ul></ul><ul><ul><li>Hypotension </li></ul></ul><ul><ul><li>PE </li></ul></ul><ul><li>ETCO 2 underestimates PaCO 2 due to deadspace ventilation </li></ul>
  23. 23. Capnography
  24. 24. Esophageal intubation
  25. 25. Inadequate seal
  26. 26. Hypoventilation
  27. 27. Hyperventilation
  28. 28. Airway obstruction
  29. 29. Curare cleft
  30. 30. Invasive BP or Arterial Line Monitoring <ul><li>Invasive, continuous measurement of arterial BP </li></ul><ul><li>Catheter in a peripheral artery connected to a transducer and display </li></ul><ul><li>Indications: </li></ul><ul><ul><li>Expected hemodynamic instability </li></ul></ul><ul><ul><li>Rigorous control of blood pressure is necessary </li></ul></ul><ul><ul><li>Need for analysis of multiple blood gas samples </li></ul></ul><ul><ul><li>Not indicated for drug administration </li></ul></ul>
  31. 31. Arterial Line Monitoring <ul><li>Technique: </li></ul><ul><ul><li>Sterile prep, gloves </li></ul></ul><ul><ul><li>Feel pulse </li></ul></ul><ul><ul><li>20G catheter for radial artery in adults, 22G in pediatrics </li></ul></ul><ul><ul><li>Secure with suture and/or clear tape or dressing </li></ul></ul><ul><ul><li>Transducer line with pressure tubing attached to IV fluids on a pressure bag set at 250 mmHg. Transducer setup infuses a few ml of saline into artery every hour to prevent clotting. Non-pressure tubing will dampen signal. </li></ul></ul><ul><ul><li>Transducer is zeroed and positioned at the level of the heart </li></ul></ul><ul><li>Possible complications: </li></ul><ul><ul><li>Distal ischemia </li></ul></ul><ul><ul><li>Infection </li></ul></ul><ul><ul><li>Hemorrhage </li></ul></ul><ul><ul><li>Any air in the line will dampen the signal </li></ul></ul>
  32. 32. Arterial Line Monitoring <ul><li>Cannulation site: </li></ul><ul><ul><li>Radial artery – most common site </li></ul></ul><ul><ul><li>Femoral artery </li></ul></ul><ul><ul><li>Dorsalis pedis </li></ul></ul><ul><ul><li>Brachial artery </li></ul></ul><ul><ul><li>Ulnar artery </li></ul></ul><ul><ul><li>Axillary artery </li></ul></ul><ul><li>Site of placement of arterial line catheter determines the shape of the arterial pressure wave. The farthest from the heart, the higher the systolic pressure and the lower the diastolic pressure. MAP remains about the same at all sites </li></ul><ul><li>Upon removal of arterial catheter hold pressure at insertion site for 3-5 minutes to prevent bleeding/hematoma </li></ul>