V l t i C h A B i f Hi tV l t i C h A B i f Hi tVolumetric Capnography A Brief HistoryVolumetric Capnography A Brief HistoryVolumetric Capnography A Brief HistoryVolumetric Capnography A Brief HistoryVolumetric Capnography – A Brief HistoryVolumetric Capnography – A Brief HistoryVolumetric Capnography A Brief HistoryVolumetric Capnography A Brief HistoryVolumetric Capnography A Brief HistoryVolumetric Capnography A Brief Historyp g p y yp g p y yM h l B J ff PhD Phili R i i W lli f d CTM h l B J ff PhD Phili R i i W lli f d CTMichael B Jaffe PhD Philips Respironics Wallingford CTMichael B Jaffe PhD Philips Respironics Wallingford CTMichael B Jaffe PhD Philips-Respironics Wallingford CTMichael B Jaffe PhD Philips-Respironics Wallingford CTMichael B. Jaffe PhD, Philips Respironics, Wallingford, CTMichael B. Jaffe PhD, Philips Respironics, Wallingford, CTff p p , g ,ff p p , g ,

i ii iTimelineTimelineAb t tAb t t TimelineTimelineAbstractAbstract TimelineTimelineAbstractAbstractAbstractAbstractO f h li i f d f CO i h i d h b hOne of the earliest infrared measurements of CO2 in the expired human breath wasOne of the earliest infrared measurements of CO2 in the expired human breath was

t d b J h T d ll i 1865 H it t k th t b f threported by John Tyndall in 1865. However, it took another century before thesep y y , yt h d th b d id Si il l f th li t t f it lmeasurements reached the bedside. Similarly, some of the earliest measurements of vitaly,

capacity by John Hutchinson reported in 1846 preceded the development of devicescapacity by John Hutchinson reported in 1846 preceded the development of deviceswhich permitted convenient measurement of flow (and hence volume) by over 75 yearswhich permitted convenient measurement of flow (and hence volume) by over 75 years.The importance of measuring volume with carbon dioxide has long been recognized byThe importance of measuring volume with carbon dioxide has long been recognized byphysiologists and clinicians Early methods such as the Haldane method and its variousphysiologists and clinicians. Early methods such as the Haldane method and its variousderivatives, used chemical absorbents, and served as the reference method for aderivatives, used chemical absorbents, and served as the reference method for a

l i f CO f V i i i h d hvolumetric measure of CO2 for many years. Various investigators sought to extend thesevolumetric measure of CO2 for many years. Various investigators sought to extend thesedi t h i l b ti b d th d t “ ti ” l i ( R i (1933) Combined mainstream CO /flowdiscrete chemical absorption-based methods to “continuous” analysis (e.g. Rein (1933) Combined mainstream CO2/flow p y ( g ( )[1])

2sensors (left to right) neonatal[1]). sensors (left to right) neonatal, [ ])

One of the earliest descriptions of the volumetric capnogram and a method to determine( g ) ,

d lt d di t i (R i i )Tyndall's experimental apparatus shown hereOne of the earliest descriptions of the volumetric capnogram and a method to determine adult and pediatric (Respironics).Tyndall s experimental apparatus, shown here “airway” dead space is that of Aitken and Clark Kennedy (1928) [2] Fowler (1948)[3]

adult and pediatric (Respironics).consisted of a long tube that he filled with variousairway dead-space is that of Aitken and Clark-Kennedy (1928) [2] . Fowler (1948)[3] consisted of a long tube that he filled with various

in describing the single breath test for nitrogen (SBT-N2) curve sought to use uniformg

(T d ll 1865) (10 11)in describing the single breath test for nitrogen (SBT-N2) curve sought to use uniform gases. (Tyndall 1865) (10,11)terminology to clarify the “meaning of dead-space” and thus divided this curve into

g ( y ) ( , )terminology to clarify the meaning of dead space , and, thus, divided this curve intofour phases: I, II, III, and IV Different methods to sample “alveolar” CO2 gas werefour phases: I, II, III, and IV. Different methods to sample alveolar CO2 gas wered l d i l di i l d l i l b h h ddeveloped, including single and multiple breath methods.developed, including single and multiple breath methods.El (1955) i l d l d CO it fi t t bli hElam (1955), using newly developed CO2 gas monitors, was first to publish Mainstream CO and ventilator derived flow( ), g y p 2 g , p

hi fil f h i ti i th th i l lit t [4] ItMainstream CO2 and ventilator derived flow capnographic profiles of human respiration in the anesthesiology literature [4]. It was 2M d l 930 CO l (f ith th 900Si lt b di id d fl V t k (1994) CO SMO Pl ! (1996) NICO(1998)p g p p p gy [ ]not until Fletcher (1980) [5] presented the concepts of dead space and CO elimination in Model 930 CO2 analyzer (for use with the 900 Simultaneous carbon dioxide and flow Ventrak (1994) CO2SMO Plus! (1996) NICO(1998)not until Fletcher (1980) [5] presented the concepts of dead-space and CO2 elimination in 2 y (S til t ) th fi t i lh i it i f di

( ) 2 ( ) ( )2a unified framework known as the single breath CO curve that this approach began to Servoventilators); the first commercialcurve showing criteria for reading i / i ia unified framework known as the single breath CO2 curve that this approach began to Servoventilators); the first commercial

l i h ( i l )curve showing criteria for reading l l i f b di id Novametrix/Respironicsgain clinical recognition In 1976 the Model 930 CO analyzer (for use with the 900 volumetric capnograph (Siemens-Elema)alveolar concentration of carbon dioxide

Novametrix/Respironicsgain clinical recognition. In 1976 the Model 930 CO2 analyzer (for use with the 900 volumetric capnograph (Siemens Elema)alveolar concentration of carbon dioxide Servoventilators) offered the first commercial volumetric capnograph featuring from recorded plateau (from Elam JAServoventilators) offered the first commercial volumetric capnograph, featuring from recorded plateau (from Elam JA mainstream CO2 and ventilator derived flow 1955) (4)mainstream CO2 and ventilator derived flow.I h l 1990’ h fi ff i CO d fl f h i if d

1955) (4)Chemical absorption -reduction of the gasIn the early 1990’s the first efforts to integrate CO2 and flow from the airway manifested) ( )Chemical absorption reduction of the gas In the early 1990 s the first efforts to integrate CO2 and flow from the airway manifested

ith th i t d ti f th i D lit (I t t i H l i ki volume was measured and indicated the quantitywith the introduction of the on-airway D-lite sensor (Instrumentarium, Helsinki, volume was measured and indicated the quantity y ( , ,Fi l d) bi i i i l d t i fl t i t l t f fl d t of the gas absorbed (Haldane 1912) (9)Finland) combining in a single adapter piece a flow-restrictor element for flow and a port of the gas absorbed. (Haldane, 1912) (9)) g g p p pto allow sidestream gas sampling The sidestream approach requires sophisticated

g ( ) ( )to allow sidestream gas sampling. The sidestream approach requires sophisticated

Pre 1920computer algorithms to align and compensate the flow and CO signals [6] Pre-1920computer algorithms to align and compensate the flow and CO2 signals [6].The mid-1990s saw the introduction of the first “all-mainstream” devices for on-airwayThe mid-1990s saw the introduction of the first all-mainstream devices for on-airwayvolumetric capnography (Novametrix Wallingford CT)[7] These devices evolved fromvolumetric capnography (Novametrix, Wallingford,CT)[7]. These devices evolved fromseparate flow and CO2 sensors connected to separate devices (e g , Ventrakseparate flow and CO2 sensors connected to separate devices (e.g., Ventrak1550/C d) d b i d CO2/fl i d i f d h1550/Capnogard) and became integrated CO2/flow-airway adapters interfaced to the1550/Capnogard) and became integrated CO2/flow airway adapters interfaced to the

h t t ( CO SMO+ NICO) Th d l t f thi f il f fl /COsame host system (e.g. CO2SMO+, NICO). The development of this family of flow/CO2y ( g 2 , ) p y 2d t ( t l di t i d d lt) i d b f k t h l i ladapters (neonatal, pediatric and adult) required a number of key technologicalp ( , p ) q y g

developments such as a novel thick film IR source a robust fixed orifice flow sensordevelopments such as a novel thick-film IR source, a robust, fixed orifice flow sensor,and extremely sensitive low cost differential pressure sensors[8]and extremely sensitive low-cost differential pressure sensors[8].With the increased recognition of the clinical value of volumetric capnography it willWith the increased recognition of the clinical value of volumetric capnography, it willlikely evolve to become the standard of care for all mechanically ventilated patientslikely evolve to become the standard of care for all mechanically ventilated patients.

ReferencesReferencesReferencesReferencesReferencesReferencese e e cese e e ces1 Arch f exp Path U Pharml 1933; 171: 3631. Arch f. exp. Path. U. Pharml. 1933; 171: 363.2 J Physiol 1928; 65: 389 4112. J. Physiol. 1928; 65: 389–411.y3 Am J Ph siol 1948; 154: 405 4163. Am. J. Physiol. 1948; 154: 405-416.y ;4 A th i l 1955 16 876 8854. Anesthesiology 1955; 16: 876–885. h d f d d i h l l CO d4. Anesthesiology 1955; 16: 876 885.l h h i d S d 1980 Method of deducing the alveolar CO2 curve and5 Fletcher R Thesis Lund Sweden 1980 Method of deducing the alveolar CO2 curve and 5. Fletcher, R. Thesis. Lund, Sweden, 1980. the dead space from the experimental CO curve6 J Clin Monit 1993; 9(5):374-80 the dead space from the experimental CO2 curve 6. J Clin Monit. 1993; 9(5):374-80. The flat part BC of the experimental curve7 Anesth Analg 2008 107: 890 904 . The flat part BC of the experimental curve i l d i fl i lThe three phases of SBT-CO2 Phase I is7. Anesth. Analg., 2008, 107: 890–904. OABC is prolonged to the left to D until the area A single adapter piece a flow-restrictor element

The three phases of SBT CO2. Phase I is 8 IEEE Eng Med Biol Mag 2010 ;29:44 52 OABC is prolonged to the left to D until the area

A single adapter piece a flow restrictor element the CO free part of the breath the8. IEEE Eng Med Biol Mag. 2010 ;29:44-52. p gFDCG l th OABCG DF d CG Geometric representation of Bohr's formula for flow and a port to allow sidestream gasthe CO2 free part of the breath, the g g ;

9 H ld J S (1912) M th d f Ai A l i L d G iffi FDCG equals the area OABCG, DF and CG Geometric representation of Bohr s formula for flow and a port to allow sidestream gas

ineffective tidal volume At the start of9. Haldane, J.S. (1912). Methods of Air Analysis. London: Griffin. CG q O CG, CGb i di l OG OF h applied to an expiration (Fowler 1948) (3) sampling This sidestream approach requiresineffective tidal volume. At the start of , ( ) y

10 T d ll J H A d f i 6 h d N Y k D A l d being perpendicular to OG. OF then representsapplied to an expiration (Fowler, 1948) (3) sampling. This sidestream approach requires

h II CO d th ff ti10. Tyndall J. Heat - A mode of motion. 6th ed. New York. D. Appleton and being perpendicular to OG. OF then represents p g pp q

sophisticated computer algorithms to align andphase II, CO2 appears and the effective 10. Tyndall J. Heat A mode of motion. 6th ed. New York. D. Appleton and the volume of the dead space DC is prolonged sophisticated computer algorithms to align and p , 2 pp

l t t Ph II d III t thCompany 1890 the volume of the dead space. DC is prolonged U d if t i l t di id d SBNp p g g

t th fl d CO i l [6]volume start. Phases II and III togetherCompany, 1890. to the right to E over a distance equal to OF Used uniform terminology to divided SBN2 compensate the flow and CO2 signals [6]. volume start. Phases II and III together

h ff i id l l ff11 Tyndall J On Radiation The "Rede" Lecture delivered May 16 1865 to the right to E, over a distance equal to OF gy 2

i f h I II III d IV dco pe sate t e ow a d CO2 s g a s [6].are the effective tidal volume VTeff11. Tyndall, J. On Radiation. The Rede Lecture, delivered May 16, 1865. (when measured horizontally) The whole line curve into four phases: I, II, III, and IV and

are the effective tidal volume, VTeff. (when measured horizontally). The whole line curve into four phases: I, II, III, and IV and Relative slope of phase III can be( y)DE th t th h i t ti proposed method for determination of

Relative slope of phase III can be DE then represents the changing concentration proposed method for determination of measured between 0 2 and 0 4 l effectivep g g

f l l CO h h i i (Aik airway deadspacemeasured between 0.2 and 0.4 l effective

of alveolar CO2 throughout expiration. (Aiken airway deadspace. ol me (Fletcher 1980) (5)of alveolar CO2 throughout expiration. (Aiken volume. (Fletcher, 1980) (5)8/11/11 MBJ and Clark-Kennedy 1928) (2)

( , ) ( )and Clark Kennedy, 1928) (2)