Ce diaporama a bien été signalé.
Le téléchargement de votre SlideShare est en cours. ×


Chargement dans…3

Consultez-les par la suite

1 sur 35 Publicité

Plus De Contenu Connexe

Plus récents (20)



  2. 2. DEFINITIONS • CAPNOMETER Capnometer is the device that performs the measurement and displays the reading. • CAPNOMETRY Capnometry is the measurement and numerical display of maximum inspiratory and expiratory CO2 concentrations during a respiratory cycle.
  3. 3. • CAPNOGRAPHY Capnography is the graphic display of CO2 concentration versus time ( time capnogram ) or expired volume (volume capnogram ) during a respiratory cycle. • CAPNOGRAPH Capnograph is the machine that generates a waveform and the capnogram is the actual waveform.
  4. 4. Capnography Measurement and display of both ETCO2 value and capnogram ( CO2 waveform) Measured by capnograph
  5. 5. Capnometer Measurement and display ETCO2 value (no waveform) Measured by capnometer
  6. 6. CARBON DIOXIDE IN CAPNOGRAPHY Cellular Metabolism of food into energy. O2 consumption and CO2 production Transport of O2 and CO2 between cells and pulmonary capillaries and diffusion from /into alveoli.
  7. 7. Ventilation between alveoli and atmosphere • If the patient stops breathing CO2will not be able to get out. Low CO2 in capnograph will trigger an alarm and alert the medical staffs.
  8. 8. WORKING PRINCIPLE • The infrared method is most widely used and most cost effective. • This technique involves beaming of infrared light through a column of a gas mixture, the carbon dioxide within the column subsequently absorbs part of the infrared energy yielding a beam of less intensity at the opposite end of the column
  9. 9. • BEER LAMBERT LAW state that there is a linear relationship between the concentration and absorbance of the solution , which enables the concentration of a solution to be calculated by measuring its absorbance.
  10. 10. • Infrared is absorbed by gases that have “two or more different atoms”. • Oxygen molecules does not absorb infrared waves because both atoms are same. • Carbon dioxide , nitrous oxide, isoflurane absorb infrared waves because they have different atoms in their structure
  11. 11. • Infrared waves have different wavelengths • A given gas absorbs infrared waves of different wavelengths differently. • Carbon dioxide maximally absorbs infrared waves of wavelengths 4.25 micrometer and nitrous oxide absorbs wavelengths of 4.5 micrometer.
  12. 12. • To be specific for a particular gas , the infrared source must emit waves having wavelengths within narrow limits. (narrow band). • To measure CO2 infrared source must emit a wavelength of 4.25 micrometer.
  13. 13. CLASSIFICATION BASED ON SENSOR SITE The basic analyser system consist consists of an infrared source, sample chamber and detector. Based on site of sensor it has two types: • Diverting or Sidestream type • Nondiverting or Mainstream type-
  14. 14. DIVERTING or SIDESTREAM type – uses a pump to aspirate gas from the sampling site to the sensor located in the main unit.
  15. 15. NONDIVERTING or MAINSTREAM type- measures gas by using sensors located in the gas stream.
  16. 16. CLINICAL APPLICATIONS • Changes in respired CO2 may reflect alterations in metabolism, circulation, respiration, the airway, or breathing system • Best method of verifying correct endotracheal tube (ETT) placement. • During resuscitation, exhaled CO2 is a better guide to the presence of circulation than the ECG, pulse, or blood pressure
  17. 17. PHYSIOLOGICAL FACTOR AFFECTING ETCO2 LEVELS INCREASE IN ETCO2 o Increased muscular activity (shivering) o Malignant hyperthermia o Increased cardiac output (during resuscitation) o Bicarbonate infusion o Tourniquet release o Effective drug therapy for bronchospasm o Decreased minute ventilation
  18. 18. DECREASE IN ETCO2 o Decrease muscular activity (muscle relaxants) o Hypothermia o Decreased cardiac output (cardiac arrest) o Pulmonary embolism o Bronchospasm o Increased minute ventilation
  19. 19. CAPNOGRAMS A NORMAL CAPNOGRAPH demonstrating the three phase of expiration Phase 1 – dead space Phase 2 – mixture of dead space and alveolar gas Phase 3 – alveolar gas plateau
  20. 20. PHASE 1 • Beginning of exhalation • No CO2 present • Air from trachea, posterior pharynx, mouth and nose or the anatomical dead space.
  21. 21. PHASE 2 Ascending phase • CO2 from the alveoli begins to reach the upper airway and mix with the dead space air • Causes a rapid rise in the amount of CO2 • CO2 now present and detected in exhaled air • Depicts perfusion Alveoli
  22. 22. PHASE 3 • Plateau phase • CO2 rich alveolar gas now constitutes the majority of the exhaled air • Uniform concentration of CO2 from alveoli to nose/mouth
  23. 23. • End of exhalation contains the highest concentration of CO2 • The “end-tidal CO2” • Normal EtCO2 is 35-45mmHg
  24. 24. PHASE 4 • Inhalation begins • Oxygen fills airway • CO2 level quickly drops to zero Alveoli
  25. 25. Shark Fin Appearance CAPNOGRAPH of a patient with severe Chronic Obstructive Pulmonary Disease (COPD). No plateau is reached before the next inspiration. The gradient between end-tidal C02 and aeterial CO2 is increased.
  26. 26. CURARE CLEFT Depression during phase 3 indicates Spontaneous respiratory effort .
  27. 27. REBREATHING Faulty expiratory valve Inadequate inspiratory flow Insufficient expiratory time Malfunction of CO2 absorber system
  28. 28. Hyperventilation Increase in respiratory rate Increase in tidal volume Decrease in metabolic rate Fall in body temperature
  29. 29. Hypoventilation Decrease in respiratory rate Decrease in tidal volume Increase in metabolic rate Rapid rise in body temperature
  30. 30. • Cardiac oscillations - cardiac action causes to-and-fro movement of the interface between exhaled and fresh gas. The CO2 concentration in gas entering the sampling line therefore alternates between high and low values.
  31. 31. • Esophageal intubation – flat trace or a rapidly descending series of curves
  32. 32. CPR – ACLS guidelines define high quality chest compressions as achieving ETCO2 pressures of at least 10-20 mmHg
  33. 33. CALORIMETRIC TECHNIQUE • Specially treated litmus paper • Colour changes indicate qualitative amount of CO2 detected • For intubated patients only • Disposable detector fits on ET tube hub • Single use • Easily impaired by moisture or secretions
  34. 34. CAPNOMASK • Capnomask is used for monitored anesthesia cases (MAC). • During moderate or deep sedation the adequacy of ventilation shall be evaluated by continual observation of qualitative clinical sign and monitoring for the presence of exhaled CO2.
  35. 35. THANK YOU