K. KHETARPAL * MATERIALS A D METHODS

Transcription

1 TOTAL RESPIRATORY COMPLIANCE OF NORMAL INDIAN SUBJECTS by K. KHETARPAL * Department f Physilgy, M.G.M. Medical Cllege, Indre The nrmal values fr pulmnary functin tests published by us earlier (5) did nt includethe figures fr respiratry cmpliance. The aim f the present study is t present nrmalfigures fr the cmpliance f the ttal respiratry system in yung Indian adults. A ntablepint is the simplicity f the methd used hich makes it easy fr clinical use in a largenumber f chest clinics in the cuntry. MATERIALS A D METHODS 22 Medical students 18 males and 4 females in the age grup years have been studied. They ere tested during rking hurs hich ensured an interval f abut three hurs frmthe last meal. They had n clinical evidence f present r past cardirespiratry disease. Cmpliance f the Respiratry system means a change in vlume brught abut by eachunit f pressure change, hen a psitive pressure is applied t the system. A simple methd fapplying the pressure and measuring the vlume change has been used. The methd f recrding as described by Cherniack and Brn (2). The apparatus cnsisted f : (1) A spirmeter filled ith 1 %, and fitted ith a COl absrber. (2) Weights f varying sie hich hen put n the spirmeter bell, prduced pressure ranging frm 2 t 14 cm H 2 inside the bell. (3) A ater manmeter cnnected ith the O 2 inlet f the spirmeter by means f a pressure tubing. The subject as tested sitting n a labratry stl. He as req uired t breath 1D cl ed circuit ith the spirmeter fr a minimum f 2 minutes 1 ensure a steady end-expiratry line (Graph l). Then a eight as placed n the spirmeter bell t create a psitive pressure in the spirmeter gas and therefre in the lungs f the subjects hich are in free cmmunicatin ith it. The increased pressure frces mre gas int the lungs and the vlume f the Res piratry system increases. The increase in vlume is nticed as a mving up f the end expiratry level f the subject h cntinues t breath fr a minimum f anther t minutes t ensure a cnstant end expiratry Graph 1 lavel again. A line as dran thrugh The Recrd f Respiratin during the test. Nte the mving the pints f end expiratin at each up f the Recrd n applicatin f the increased pressure. 'Present Address: Department f Physilgy, All India Institute f Medical Sciences, Ansari Nagar, Ne Delhi.

2 46 Khetarpal January 1 Ind. J. Physil. & Pharma f the t level (Graph 1), and the vertical distance beteen the t represents change in vlume brught abut by the pressure hich is simultaneusly read fr the manmeter. This change in vlume is crrected fr the cmpressin f gas and ater und the bell by the applicatin f the same eight hen the subject is nt cnnected ith spirmet The vlume is changed t V at BTPS. This prcedure as repeated t prduce pres ure vari tins.beteen 2 t 14 cm H 2. The change in vlume brught abut by each end-expiratry pre sure as pltted agai it after the abve crrectin, and a pressure vlume curve as dran thrugh the e pain (Graph 2). The cmpliance f the ttal re piratry system as calculated frm the traight pm tin f the curve. The prcedure as repeated in the same individual n different days a almst identical figures ere btained (Graph 2). Vital capacity and MBe ere tested (/) a: - -.J 1.6 Z ' 2 x -.J > O S I.L. C> «::I: () " 4 ex x PRESSURE (CWlHg ). Graph 2 Pressure Vlume Relatinship f The Respiratry System f a Subject 11 t diffrent days.

3 Respiratry Cmpliance 47 the spirmeter after remving the CO 2 absrber and the valves. Height and eight f the subjectere measured and the bdy surface area as cmputed frm Dubis Cbart. OBSERVATIONS AND RESULTS The figures fr physical characteristics and ventilatry functins ere as flls Males: 18 subjects Mean Range S.D. Age, (years) ±I Height, (cm) ±6. Weight, (lbs.) ±8.1 BSA, (M2) ±.9 V.C., (Litres) 3.5 rl ±.44 MBC, Litres/min ±2 Ttal Respiratry cmpliance f these subjects as in the range 8-'12 ml/cm/h 2 ; Mean-l l l ml. S.D.±2.4 Females: 4 subjects Mean Range S.D. Age, (years) ±1.4 Height, (cm) ±2.9 Weight, (lbs) ±12.4 BSA, (M2) ±.29 V.c., (litres) ±.22 MBC litres/min ±9 Ttal respiratry cmpliance f these subjects as in the range 8-16 ml/cm H 2 ; Mean96; S.D.±12.. Graphs 3 t 6 present the relatinship beteen ttal respiratry cmplianceand height, BSA, V.C. and MBC respectively as measured by this methd. Crrelatincefficients ere calculated fr male subjects female grup being very small, and the value f it as fund t be- V.C. and Ttal cmpliance MBC and Ttal cmpliance Height ahd Ttal Cmpliance = ,

4 48 Khetarpal January lnd. J. Physil. & Pha c.. ' :r: 12 (,) I. (j <... -r -1. (.....J 8 I e L. i HEIGHT IN C,..,. Graph 3 Relatinship f the Height f the Subjects ith the Ttal Cmpliance f the Respiratry System DISCUSSION Since this is a pressure breathing technique, it is imprtant t ensure cmplete relaxati f the respiratry muscles at the end expiratry pint hen the pressure and vlume measu ments are made. It has been shn by Jhnsn and Mead (3) that the results btained pressure breathing techniques are similar t thse. btained by the vluntary relaxatin meth f Rahn et al (4). The pressures applied t the respiratry system in ur expreiments \I kept bel 15 cm H 2 because it is nly in this range tbat the abdminal muscles have shn by Agstini and Mead (1) t exhibit cmplete relaxatin. The pressure breathing tee niques are mre accurate because they give less scatter f results as cmpared.1 the vlunt. relaxatin methd hen the test i prefrmed n the same subject at different times in untrai ed individual. Thi has been cnfirmed by the authr as can be seen in Graph 2. The val

5 12 1 Respiratry Cmpliance 49 r I " \4 I/J ILl a:.j 12 v ILl Z <t: -.J e, l: 1..J <t: ' 4 J' BODY SURFACE AREA (.METERS) Graph 4 Relatin $I&ipf the Bdy Surface Area & Ttal Cmpliance f the Respiratry System in different Subjects. ill tb.e study presented here apprach very clsely thse f Cheruiack and Brn's series f thesame age grup, The mean value fr ttal cmpliance f the female subjects is ler than f males as is true fr all ther pulmnary functin values. The Crrelatin Cefficients als pint t the fact that heigbt, vital capacity and MBC vary in the same directin as the ttal cmpliance. In vie f these facts and the simplicity f the methd used in the present study the authr recmmends that this methd shuld be used fr rutine study f ttal cmpliance in the respiratry labratries.

6 5 Khetarpal 14 :r: -12 u <,.J UJ 1 <t -...J CL :E u <t ' '5.- VITAL CAPACITY IN LITRES. Graphs 5 Relatinship f Vital Capacity and Ttal Respiratry Cmplinace in different subjects. SUMMARY ND CONCLUSIONS I. Ttal respiratry cmpliance f 22 nrmal Indian subjects has been studied using rh: methd f Cherniack and Brn. 2. The ttal cmpliance f male ubjects is III ml/cm±h 2 S.D.±2.4 and females. 96 nil/cm H 2 S.D.± A significant crrelatin i fund beteen ttal cmpliance and height, V.c. an MBe.

7 l J: (J <, (j) er:...j Z...J Q.....J f I. I Respiratry Cmpliance I I I I 6L Relatinship f Maximum MBC LITRES/MIN. Graph 6 Breathing Capacity and Ttal Cmpliance f the Respriatry System in different subjects. REFERENCES 1. Ag tini, E. and J. Mead. Statics f the Respiratry system. Hand Bk f Physilgy by Fenn and Rahn; Sectin 3, Respiratin. I: 387. William and Wilkins C. Baltimre. 2. Cherniack, R.M. and E. Brn. A simple methd fr measuring Ttal Respiratry Cmpliance. Nrmal values fr males. J. Appl. Physil. 2: (1), 87, Jhnsn, L.F. Jr.; and Jere Mead. Vlume-Pressure relatinship during pressure breathing and vluntary relaxatin. J. Appl. Physil. 18: 55, Rahn H.; A.B. Otis; L.E. Chadick and W.O. Fenn. The pressure vlume diagram f the thrax and lung. Am. J. Physil. 146: 161, Vishanathan R., S. Jain, K. Kapr and G. Natarajan. Pulmnary Functin Tests. lnd. Jur. Chest Diseases 1 : 51, 1959.