1960s, Diagram, Exercise, Qc, Steady-State DLCO

DLCO, Qc, Vc during Exercise 1960

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Single_Breath_DLCO_JAP_v015_n5_p0893_1960

From Johnson RL, Spicer WE, Bishop JM, Forster RE.  Pulmonary capillary blood volume, flow and diffusing capacity during exercise.  J Appl Physiol 1960; 15: 893-900

“Measurements were made as follows: after exhaling to residual volume, the subject went on the mouthpiece and rapidly inhaled a measured volume of the gas mixture from bag A.  This breath was held for a measured time after which is was exhaled rapidly.  The first liter of exhalate was allowed to clear the dead space, after which tap A was turned 90 degrees counter clockwise and an alveolar sample of a bout a liter was collected in bag B.  t was not convenient to clamp this wide-mouthed sampling bag and remove it; therefore, the sample was aspirated into another removable bag C, in which it was sealed and set aside for later analysis.”

1950s, Diagram, Single-Breath DLCO

DLCO, Single-Breath, 1956

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Single_Breath_DLCO_J_Physiol_v132_n01_p0232_1956

 

From Bates DV, Pearce JF.  The pulmonary diffusing capacity; a comparison of the methods of measurement and a stuudy of the effect of body position.  J Physiol 1956; 132: 232-238.

“The measurement of diffusing capacity by this technique was performed by the method described by Forster et al (1954) with the following slight modifications; (a) the helium concentrations were measured by katharometer and not with a mass spectrometer; (b) the duration of the breath-hoding was accurately timed on a rapid kymograph record since this could not be done from the mass spectrometer record.

“Details of this circuit are shown in Fig 1.  The procedure used was as follows.  The apparatus was prepared by filling bag (B), the envlosed bad (A) and the connecting tubing with inspired gas of the following composition: He, 14%; N2, 65.7%; O2, 20%; CO, 0.3%; from a prepared cylinder of this mixture.  Mixing was ensured in the apparatus by alternate pressure on bag B and on the spirometer.  The spirometer itself and the aspirating bottle contained air.  Tap Y was turned to connect the mouthpiece with the flexible tube that joins with tap Z.  The latter was turned to that all three limbs were in communication.  The subject, wearing a nose clip, now breathed from the spirometer through the mouthpiece, and his quiet respirations were recorded on the kymograph.  On command, he expired to his full extent, tap Y was turned, and he took a full inspiration from A as quickly as possible.  He held his breath about 10 sec as timed by a stopwatch, and expired as rapidly as possible.  After about 1 l. had been expired, as indicated on the kymograph, the operator turned tap X to collect the alveolar gas in bag C, which had been previously evacuated.  After the sample had been collected in bag C, tap X was turned to its previous position.  The duration of collection of the expired alveolar sample was checked from the kymograph…”

1940s, Diagram, N2 Washout

N2 Washout FRC, 1940

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N2_Washout_System_JCI_v19_n4_p609_1940

From Darling RC, Cournand A, Richards DW.  Studies on the intrapulmonary mixture of gases.  III. An open circuit method for measuring residual air.  J Clin Invest 19; 1940: 609-618.

“The arrangement consists essentially of two open breathing circuits fitted with flutter valves (F1, F2, F3, F4) connected adjacent to the mouthpiece (M) at the valve (v1) which cane be used to shift the breathing from one circuit to the other.  One circuit, the main circuit, is attached on the inspiratory side to a rubber anesthesia bag (B1), this in turn to an oxygen tank. The expiratory side leads to a Tissot gasometer of 100-liter capacity.  On the side circuit there is an additional valve with which the inspiratory gas flow can be cut off during alveolar sampling.  The inspiratory arm of this circuit leads to an anesthesia bag (B2) and oxygen tank, which were replaced by by a tube leading from outside air when atmospheric air was the desired breathing mixture.  On the expiratory arm evacuated sampling tubes labeled “alv” are inserted close to the valve (V2).  The dead space from mouthpiece to these tubes is about 100 cc.

“The procedure for determination of functional residual capacity air by the open circuit method was started with V1 turned to the side circuit.  The main circuit and gasometer were thoroughly washed out with oxygen. Six successive washouts of 10 to 20 liters each were found adequate.  After the washing, V2 was opened to connect the main circuit to the open room and a flow of 4 to 5 liter per minute of oxygen was maintained in this circuit.  The bag (B2) in the side circuit was replaced by a room inlet tube.  Then with V1 unchanged, the subject under basal conditions, was attached to the mouthpiece.  When breathing quietly, he was instructed to exhale maximally for an alveolar sample.  At the same time, the valve (V2) was turned to close the inspiratory side of the circuit.  The alveolar sample was taken at the end of approximately 5 seconds of expiration and V2 was reopened.  The sample, designated “alv.d” was thus a Haldane-Priestly alveolar sample representing an attempted measure of average lung gas concentration on room air breathing.

“Following this sampling, at least two minutes of room air breathing were allowed in order to restore quiet breathing. The V2 was turned to direct the oxygen flow of the main circuit into the gasometer and V1 was turned to the main circuit at exactly the end of a normal expiration.  By watching carefully the respiratory rhythm for the few previous breaths, this latter valve turn could be made accurately at the desired moment.

“For the next seven minute of oxygen breathing the expired gases were collected in the gasometer.  During this time, the oxygen flow was maintained to keep the bag (B1) about one-half full.  The period of seven minutes was the standard one used….

“At the conclusion of the seven minutes, the valve (V1) was again turned to the side circuit, this time at any point during the expiration, preferably near the beginning.  At the same time, the subject was instructed to expire fully for an alveolar sample.  For this, as for all alveolar sampling, the valve (V2) had been turned to close the inspiratory arm of the circuit.  This alveolar sample, designated “alv.p” was taken at approximately five seconds of expiration as before.

“Following this, the patient was disconnected and the main circuit flushed with 5 to 10 liters of oxygen, wash gas being allowed to mix in the gasometer with the collected expirated gas.  The valve (V2) was next turned to close the entire gasometer contents, whose volume and temperature were taken.  A sample was taken from the gasometer for analysis within one to two minutes after first flushing out the inlet and outlet pipes of the gasometer proper with the collected gases.  This sample will be designated as “Tissot” sample in future references.”

 

 

 

1960s, Diagram, DLO2, Steady-State DLCO

Steady-State DLCO and DLO2 at Altitude 1965

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DLCO_DLO2_JAP_v020_n3_p0519_1965

From Kreuzer F, Van Lookeren Campagne P.  “Resting Pulmonary Diffusing Capacity for CO and O2 at Altitude”.  J Appl Physiol  1965; 20: 519

The supine subjects rested for about a half an hour and then breathed, in varying sequence through a low-resistance valve, one of the following gas mixtures listed in Table 1, first without CO for some 10 min, and subsequently with 0.1% CO.  In this way similar inspiratory O2 pressures were attained for the three levels of oxygenation at both altitudes (about 80, 150 and 400 mm Hg, respectively, with the following average alveolar PO2 in mm Hg: at sea level 46.5, 1.7.6 and 382; high altitude: 53.6, 117 and 365).  After equilibration with the CO-free gas mixture the inspiratory circuit was switched to the corresponding CO-containing muxture (Fig. 1, stopcock A or B).  On and one-half minutes were allowed for equilibration with 0.1% CO which is considered sufficient by most authors; aftere simultaneous washing out of spirometer and connections towards the end of this period, stopcocks C and D were turned to collect expired gas in a 9-liter spirometer with continuous recording of breaths during about a a half a minute, bringing total exposure to CO to some min per run.

The diverse, quirky and mostly forgotten history of Pulmonary Function testing