of · 2003-03-19 · demonstrated by Leake, Leake, and Koehler (1923), and by Gram& (1922) who found no acetone during prolonged anesthesias. Leake interprets his findings on acetone

ETHER ANESTHESIA.

III. R6LE OF LACTIC ACID IN THE ACIDOSIS OF ETHER ANESTHESIA.

BY ETHEL RONZONI, IRENE KOECHIG, AXD EMILY P. EATON.

(From the Laboratory of Biological Chemtisry, Washington University School of Medicine, St. Louis.)

(Received for publication, July 2, 1924.)

That the alkali reserve during ether anesthesia is reduced from 13 to 34 volumes per cent and that this condition is accompanied by an increase in the hydrogen ion concentration of the blood have been shown by a number of investigators, Van Slyke, Austin, and Cullen (1922). It has recently been shown that these changes take place early in anesthesia and that anoxemia alone is not responsible (Cullen, Austin, Kornblum, and Robinson (1923)). That they are not due to the production of acetone bodies has been demonstrated by Leake, Leake, and Koehler (1923), and by Gram& (1922) who found no acetone during prolonged anesthesias. Leake interprets his findings on acetone bodies as evidence against the formation of other acid products. This would leave withdrawal of base from the blood as the alternative explanation. The accumulation of lactic acid in the blood does not seem to be excluded as the possible cause of changes in the acid-base equilibrium. The importance of lactic acid in the acidosis of muscular exercise and the influence oxidative processes have on its accumulation suggest it as possibly responsible for these changes.

In this paper an attempt has been made to correlate changes in the lactic acid content of the blood with changes in the acid- base equilibrium, and at the same time to show whether or not the amount in the blood depends on the pH as controlled by the CO2 tension, in this condition, as has been found by Anrep and Cannan (1923) in experimental acidemia and alkalemia. An effort was made to throw light on the possible source of lactic

465

Ether Anesthesia. III

acid and the cause of its accumulation. The degree of cyanosis or the oxygen content of capillary blood is the nearest index we have of the oxygen supply to the tissues. A comparison of oxygen content of arterial and venous blood has been studied in an attempt to determine the condition of tissues in regard to the oxygen supply.

Procedure.

Animals.-Dogs, weighing between 10 and 15 kilos, were used, a size that could be easily handled by two persons and sufficiently large that the withdrawal of 150 to 206 cc. of blood would not seriously disturb the condition of the animal. The animals were fed as usual on the the day preced- ing, but received no food on the day of the experiment. They were placed in a cage the evening before and kept as quiet as possible until the experiment was started. The dogs were tied to the board, usually without struggling, and the initial sample of blood was taken. Ether was then administered. In all cases the normal temperature of the dog was maintained by means of a heating pad controlled by a thermostat placed in the rectum of the dog, as described by Bishop (1923).

Induction of Anesthesia.-Anesthesia was induced by the drop method. A wire cone covered with gauze was placed over the nose of the animal. Even with the greatest care we found ourselves unable to produce anesthesia without some excitement and struggling on the part of the animals, Experi- ments I, II, and III. To reduce this to a minimum we found the beet method was to decrease the period of induction. Since the concentration of ether in the blood depends on the alveolar tension, and since the stimulus to respiration occasioned by increasing the CO1 tension had already been shown to increase the rate of elimination of ether (Haggard and Henderson (1919), White (1923), Ronzoni (1923)), it naturally occurred to us that induction could be hastened in thesame way. This has recently been demonstrated by Haggard (1924) to be true. The CO, concentration was increased by using a close fitting mask and allowing the animal to rebreathe into the mask until the rate of respiration was increased before pouring on the ether. I f the respiration was first stimulated there was no reflex inhibition due to irritation of the mucous membrane of the nasal passage by ether. This procedure also decreased the oxygen tension, but since the whole procedure was over in a period of about 2 minutes this was thought to have little effect on the subsequent blood reactions. Analysis of the air in the mask showed from 6 to 8 ~01s. per cent CO1 and from 15 to 18 ~01s. per cent Oz. The struggling was vigorous, but of short duration.

After induction, tracheotomy was performed and the animals were attached to the ether apparatus described in a previous paper (Ronzoni (1923)). I f the animal was to recover the mask was replaced byafew layers of gauze t.o insure adequate ventilation and the drop method continued. In Experiments VI and VII the mask was used. The oxygen unsaturation

E. Ronzoni, I. Koechig, and E. P. Eaton 467

of the blood in the early part of these experiments shows that the ventilation was interfered with. In Experiment VIII no mask was used. The increased Oz unsaturation was due to depression of respiration accomr parrying the deep anesthesia.

Collection of Samples.-Blood was drawn from the femoral artery into a syringe previously coated with and containing about 4 inch of oil. The initial sample in each case was taken through the skin and in those cases where the animal was allowed to recover subsequent samples were drawn in the same manner. Otherwise the artery was exposed and the blood taken by needle and syringe. When removing the needle the circulation was stopped for a few seconds by gentle pressure, thus allowing time for the closing of the puncture hole. The blood was then allowed to resume its flow. This procedure necessitated no part of the body being cut off from the general circulation for more than a few moments.

The blood was transferred from the syringe under oil to a tube containing enough neutral oxalate to make 0.3 per cent and sodium flouride to give a concentration of 0.05 per cent, shown by Evans (1922) to prevent production of lactic acid. After collection the blood was placed in the refrigerator until analyzed. That’ there was no significant change in the blood during the interval between drawing and analysis is shown by the fact that there was no measurable change in pH. Blood to be usedforetherdeterminations was drawn directly into a pipette graduated in cubic centimeters. After enough blood for duplicate determinations was collected this was measured directly into aeration flasks containing oxalate. The last portion of blood, the layer exposed to the air, was discarded. The aeration tubes of the flasks were closed until aeration was started-within a few minutes after drawing the blood.

Blood gas analyses were made on whole blood in the Van Slyke constant pressure apparatus, using the technique described by Van Slyke and Stadie (1921). The 02 and CO, contents of the blood as drawn were determined. A 5 cc. sample was equilibrated with an air and CO2 mixture, containing approximately 5 ~01s. of COZ and 19.5 vols. per cent 02. Theseequilibrations were carried out in liter bottles at a temperature between 36” and 38°C. The blood was removed under oil without exposure to air. The gas mixture was trapped in the bottle and drawn out into a Haldane gas apparatus under reduced pressure for analysis. Thus the actual tension of CO, and 02 with which the blood was in final equilibrium was determined. Analysis of a sample of blood so equilibrated gives both the CO, and O2 capacity of the blood, proper correction being applied for the amount of physically dissolved 02. All gas analyses were made in duplicate, usually by two observers.

The possible effect of ether contained in the blood on the blood gas determinations suggested itself to us early in the investigation. We found that concentrations of ether similar to those existing in the blood of an- esthetized animals caused a considerable error in the CO2 determinations as has also been reported by Austin (1924). An investigation of the conditions of our elrperiments shows this error to be actually negligible. As

468 Ether Anesthesia. III

already described the blood was collected in an oil-coated syringe and allowed to stand for some time under oil before analysis. The tubes used for collection were 2 cm. in diameter, and, since whole blood was used, stirring was necessary to mix the corpuscles and plasma before each sample was measured. Examination of the blood after the samples had been removed for gas analyses showed a great reduction in the amount of ether in the blood. This is to be expected from the fact that the partition coefficient for ether between oil and blood is greatly in favor of the oil. Table I gives data from a series of bloods examined; the maximum ether found in blood at the time the gas analyses were made was 45 mg. per 106 cc. This amount of ether added to a bicarbonate solution of a known strength increased the apparent volume of COZ, obtained from 1 cc. of the solution, by about 0.01 cc. If the total volume.of CO1 contained in 1 cc. of blood amounted to 0.5 cc., then the error due to COz would be 2 per cent and the apparent CO, content would be 2 per cent too high. The lower the CO* content the greater the error due to ether. Since the CO2 content of blood

TABLE I.

Amount of Ether Contained in 100 Cc. of Blood, Calculatedfrom the Distri- bution Ration and Relative Volumes of Blood and Air.

When drawn.

ml. w7.

162 45.0 183 41.3 196 38.5 132 40.2

Ether per 100 cc. of blood.

After equilibration.

WT.

11.3 12.7 13.7 9.4

as drawn falls as low as 25 vols. per cent the error might be increased to 4 per cent.

In the equilibration for the determination of CO* capacity the volume of gas with which the blood was in equilibrium was 266 times that of the blood used. The distribution ratio for ether between air and blood at 38” is 1: 15. So the blood after equilibration would contain only l/14 the total ether, or in the case of blood originally containing 162 mg. per 100 cc., 11.3 mg., an amount too small to have a measurable effect.

Values for CO2 content of blood as drawn may therefore be from 2 to 4 per cent too high; and the apparent changes less than those really existing. These errors would be reflected in the calculated values of CO, tension. Such errors fall easily within the limits of error in lactic acid determinations. The values for CO, capacity of the blood are not influenced by ether since the amounts present caused no measurable effect in CO, determination.

The pH of the blood was determined by Cullen’s (1922) calorimetric method. Clausen’s (1922) method was used for lactic acid. This deter-


mination often had to be left till the following day. In all cases the blood filtrates, however, were made immediately after drawing the blood, the sugar was precipitated, the filtrate placed in the refrigerator, and analyses were made within the next 24 hours, a procedure which has been found tobe safe. To eliminate the possibility of the ether in the blood affecting the determination of lactic acid or the possible influence of acetone bodies, the filtrates after having been measured for lactic acid determinations were acidified and aerat.ed for 15 minutes at a temperature of 100”. Sam- ples that were aerated showed the same lactic acid content as similar samples unaerated, which shows that the ether has no effect and that acetone does not accumulate. In fact, the lactic acid of the aerated sample always ran a trifle higher than that of the unaerated. The differences were well within the limits of error of the lactic acid method, but were always in the same direction, an observation which we are unable to explain.

Ether determinations were made by a modification of the Nicloux method described by Shaffer and Ronzoni (1923). Blood sugar determinations were made on all samples, but these results will be discussed in a future paper.

Calculation. of Data.

In all cases the pH and COz content of the blood were determined. The COz tension was calculated by means of Hasselbalch’s equation

BHCOa pH = pI<r + log H

2 8

crp 100 H&O8 = 760 = 0.01316crp

BHCOs = COz - 0.1316 crp

Mc- COa tension =

CO* iiustin, Cullen, Hastings,

0.1316 cx (lOnH-n”L + 1) vgy2) Peters, and Van Slyke

>

p is partial pressure of COz. For at the solubility coefficient of COz in whole blood, Bohr’s (1905) value 0.511 was used. 6.20 was taken as the value of pK1, this having been determined on dog’s blood by Van Slyke and coworkers. Samples of the same bloods were also equilibrated with a known tension of COz and the CO2 capacity was determined. This gives the data for the general slope of the absorption curve of fully oxygenated blood when correction is made for O2 unsaturation of the ‘blood as drawn. These were plotted on CO2 diagrams introduced by Haggard and Henderson (1919) and the volume per cent COz read off at a


constant CO* tension 38 mm. for purposes of comparing the changes occurring in the alkali reserve. Corrections for the oxygen unsaturation of the arterial blood as drawn were made by the formula of Peters, Barr, and Rule (1921), K X Hb = D, where K is a constant, Hb is oxygen unsaturation expressed in volumes per cent, and D is the change in level of absorption curve expressed in volumes per cent of COz. The value for K of 0.27 was used as

PC4 10 LO 30 40 SO 60 i

9

/

/

10 Mm. t

l CO2 content as drawn. o Corrected for Oz unsaturation. X Equilibrated sample.

CHART I. Data from Experiment VII.

determined by Doisy, Briggs, Eaton, and Chambers (1922). Chart I, from the data of Experiment VII, shows the graphic method.

The changes in pH, CO2 tension, alkali reserve at a constant CO2 tension, and lactic acid, expressed in terms of lowering of COz capacity, are plotted for all experiments. Protocols are given in the tables and show the determined and calculated values on which the diagrams are based.

r.10

7.00


RESULTS AND DISCUSSION.

Relation of LacticAcid to Changes inAlkali Reserve.-The accumu~ lation of lactic acid in the blood during anesthesia accompanier; the fall in pH and in the alkali reserve as measured by the CO* capacity at a constant CO2 tension. The relation between lactic acid increase and the fall in CO, capacity of the blood may be seen in Charts II, III, and IV, and is summarized in Table II. Assuming that 4 mg. of lactic acid reduce the COz capacity 1 volume per cent, the accumulation of lactic acid does not correspond to the fall in alkali reserve. That this is an important factor, however, is obvious. It is not to be expected that even though the accumula-

TABLE II.

Fall in CO2 Capacity Determined and Calculated from Lactic Acid.

hr.% min. II 5 0

III 1 45 IV 3 40

v 2 5 VI 2 5

VII 2 0 VIII 1 0

IX 2 0

ma.

50.6

33.7 49.2 37.0 41.9 64.0 30.5 41.9

_ c 01. PCI Cwal

18.7 15.3 12.2

9.0 15.4 13.0 12.0 10.5

01. per cen1

12.6 8.4

12.3 9.2

10.5 16.0

7.6 10.5

per cent -33.2 -44.1

+1.0 +2.2

-31.8 +23.1 -36.7

zko.0

0.49 0.29 0.25 0.24 0.25 0.27 0.37 0.18

T-

I dctic acid increase.

I Fall in CO% capacity.

Deter- mined.

- lelculnted. Differ-

ence.

1 DfXV%l8C in pH.

-

, Durntion of anesthesia.

tion of lactic acid was entirely responsible for the change in CO2 capacity and pH, the amount in the blood at any one time would exactly correspond, since undoubtedly the lactic acid is produced in the tissues and must be in higher concentration there than in the blood until equilibrium had been reached. At any time there might be a withdrawal of base from the blood to the tissues without a corresponding increase of lactic acid apparent in the blood.

Recent experiments of Stehle and Bourne (1924) show that phosphoric acid leaves the muscles during anesthesia and sojourns in the liver until the reassumption of kidney function after the recovery of the animal; and since the transport of this must be through the blood, it is suggested that the increased acidity of the blood is due to the discharge of phosphoric acid from the muscle.



I 1. -. I


E. Ronzoni, I..Koechig, and E. P. Eaton 475

Since the changes in blood phosphates were not followed the extent to which this would actually account for changes in the alkali reserve of the blood is not known. The same investigators state that they found no excretion of lactic acid in the urine during or after anesthesia. This is not a good criterion of conditions existing in the blood since it is a well known fact that only a small part of the lactic acid present in the blood is excreted by the kidney, and besides, the kidney function is markedly interfered with by anesthesia.

In Experiments II and IV, Chart II, Experiment III, Chart IV, and Experiment VII, Chart III, where the early stages of anesthesia were followed closely, we did not find such constant and abrupt changes as reported by Cullen, Austin, Kornblum, and Robinson (1923). With the exception of Experiment IV each case shows a fall in COz capacity as early as 4 minutes after starting the ether. In Experiment II there was marked struggling of the animal while ether was being administered and during the first half hour the anesthesia was so light that all reflexes were present and the animal trembled considerably. This would account for the fact that the alkali reserve fell abruptly, accompanied by an accumulation of lactic acid, then rose again when a steady state of anesthesia was reached. At least part of the initial fall in pH can be accounted for by the increasing COz tension in the early part of the experiment which was caused by choking and reflex inhibition of respiration. A fall in COz tension accompanied the establishing of regular respiration when narcosis was complete. During the last 14 hours of the experiment the concentration of ether was increased. Respiration was depressed and the CO2 tension showed a continued rise, but the 02 unsaturation was not increased. There was a continued drop in the alkali reserve, but no indication of an increase in the rate of fall due to increasing the depth of anesthesia. The lactic acid showed a slightly more rapid accumulation with high concentration of ether. Experiment IV shows a similar effect due to early irregularities in anesthesia. The first drop in pH seems to be due to a rise in COz tension caused by reflex inhibition of respiration. The subsequent rise in pH without change in CO% capacity is due largely to the marked fall in CO2 tension. The early changes in lactic acid are slight enough to be within the limits of accuracy of the method and are not, significant. By


the time the third sample was drawn the anesthesia had been regulated so that from this point the concentration in the blood remained constant and high. The respiration was not depressed, but remained almost constant until it stopped rather abruptly in 4 hours and 20 minutes. The heart continued beating for about 4 minutes after respiration failed. The last sample of blood was drawn from the heart.

During recovery there is a complete return to normal in from 3 to 5 hours. The lactic acid, CO2 capacity, and pH all return at the same rate. Experiments V, VI, and VII, Chart III, were all done on the same animal at intervals of 1 week. In each experiment the depth of anesthesia was the same as shown by the ether concentration. In Experiment V the fall in COz capacity was less marked than in either of the subsequent experiments, as is the accumulation of lactic acid. The fact that the O2 capacity and the level of the initial absorption curve remained the same in the three experiments indicates that the general condition of the animal had not been interfered with by repeated bleedings and anesthesias. The possible relation to O2 tension and of COz tension and pH to lactic acid accumulation will be discussed later.

In Experiment IX, at the end of the 1st hour of recovery, though the lactic acid was less, the CO2 capacity had increased, and the pH was lower than at the end of the anesthesia. This fall is accounted for by the rise in COz tension. In this dog there was a marked secretion of saliva. The dog choked several times during the experiment and undoubtedly swallowed a large amount of saliva, containing ether. This was the only case of severe vomiting after anesthesia and suggests the presence of ether in the stomach as the cause of vomiting.

On the day following the experiment there was no indication of acidosis in any of the four cases observed. Tests for acetone bodies in the urine were negative. This would point to the fact that the acidosis clinically observed after operations is postoperative rather than postanesthetic and is not caused by the ether, but is rather referable to the condition of the patient or to the shock caused by the operation.

Concentration of Ether in Rektion to Production of Lactic Acid.- Variations in concentration of ether between the limits that will


abolish reflexes and those that will produce respiratory failure seem to have little influence on the rate of production of lactic acid, other factors remaining constant. In very light anesthesia when consciousness alone is lost and reflexes are still present, move- ments on the part of the animal affect the lactic acid content of the blood. In Experiment II there was trouble in adjusting the ether concentration so that for the first half hour anesthesia was very light. The animal trembled voilently for a few minutes after the initial violent struggling. The lactic acid in this case was increased during the first 30 minutes, then fell with a subsequent rise. When anesthesia is so deep that respiration is depressed asinExperiments IV and VIII the accumulation of lactic acid is not greater than in other experiments. The high concentration of ether in the blood in Experiment III was apparently due to a progressive lipemia, since the concentrat.ion of ether remained constant in the air breathed. The increased concentration of ether in the blood was due to a change in the distribution ratio. This has no effect on the lactic acid production. Table III summarizes the data obtained from various experiments.

CO2 Tension.-With the exception of Experiments IV, IX, and during the second 30 minutes of Experiment II, the CO2 tension during the administration of ether is greater than when the initial sample was drawn. That the lactic acid accumulation during anesthesia is not due to an increase of pH caused by a fall in COZ tension is obvious from these experiments, Table IV. In only one case is there an increase in pH during any part of the experiment. Cullen and coworkers (1923) found no increase in pH at any time during the early stages of anesthesia when following the blood reaction very closely. Under the conditions of ether anesthesia, then, the contentions of Anrep and Cannan (1923) that the accumulation of lactic acid in the blood is controlled by the pH seem not to be justified.

Reduced Oxidation.-The cause of the accumulation of lactic acid during ether anesthesia becomes a subject of interesting speculation. The amount of lactic acid in the blood is determined not only by its rate of production but by the rate of removal. Muscular contraction involves the production of lactic acid and if its removal cannot keep pacewith the increased rate of production, lactic acid accumulates in the blood and other tissues of the


body. Assuming muscular activity to be the source of lactic acid, the fact that it is reduced to a minimum during anesthesia suggests that increased production does not explain its accumulation. The fact that narcotics follow the Meyer-Overton law as de-

TABLE III.

Relation of Depth of Anesthesia to Accumulation of Lactic Acid.

Experi- ment No.

11* III

IV V

VI VII

VIII IX

bxease in lactic acid.

1 hr. 2 hrs.

160 25.7 128 32.0t 126 2a.ot 120 46.5 183 30.5 115 31.8

36.4t 37.0 41.9 64.0

41.9

-

RelXlarks.

Anesthesia variable. Increasing concentration of ether

in blood. Tension constant. Deep anesthesia. Moderate anesthesia.

‘I “ low 0% tension. “ “ L‘ ‘L ‘I

Deep anesthesia. Moderate anesthesia.

*Experiment I omitted since no initial sample of blood was obtained. tDetermination not made onexact hour. These values were interpolated.

TABLE IV.

Changes in CO2 Tension, pH, and Lactic Acid at End of 1 Hour of Anesthesia.

Experiment No. COz tension change. pH decrease. Lactic acid increase. -

II III IV

V VI

VII VIII

IX

vol. per cent -1.0 +s.7 -2.7 +9.5*

+12.0* f23.9 +29.4

-1.3

0.09 0.23 0.12 0.16* 0.12* 0.26 0.37 0.05

mg. 7x7 100 cc.

27.0 27.7 25.7 32.0* 20.9* 46.5 30.5 31.8

-

*These values were interpolated.

-

-

pressants of oxidation, as they do in their activity as anesthetics, that is, the higher members of a homologous series work in smaller concentrations (Warburg and Wiesel(l912))) leads to the suggestion that we have here an interference with oxidation, and therefore,


a decrease in the rate of removal which would account for the accumulation of lactic acid in the blood.

In Experiment II the removal of lactic acid formed in the first half hour accompanying, presumably, increased muscular activity, would indicate that the ability of the body to remove lactic acid had not been completely impaired by the anesthesia.

Oxygen Iinsaturation of Arterial Blood.-This was determined in an attempt to throw light on the conditions of the tissues in regard to oxygen supply. In Experiments V, VI, and VII the same animal was used. Experiment V shows the least degree of oxygen unsaturation and the smallest increase of lactic acid in the blood. However, we find on examining Experiments VI and VII that in No. VI, where the oxygen unsaturation was as much as 11.7 volumes per cent or 59 per cent of the total oxygen capacity, that the lactic acid increase was 41.9 mg. whereas in No. VII, where the oxygen unsaturation varied between 3 and 9 volumes per cent or between 15.8 and 47 per cent of the total oxygen capacity, the lactic acid increase was much greater, 64.0 mg. per 100 cc. of blood. In these experiments the oxygen unsaturation was due to mechani- cal interference with ventilation. In Experiment VIII the respiration was depressed with a marked unsaturation of the arterial blood. At the end of 1 hour the lactic acid had increased 30.5 mg. over the initial value. However, in Experiment IX, where the hemoglobin of the blood was 100 per cent saturated during the 1st hour 31.8 mg. of lactic acid accumulated per 100 cc. of blood. Oxygen unsaturation of arterial blood, then, does not appear to be the influencing factor.

The oxygen content of arterial blood is no adequate index of the oxygen environment of the tissues. The rate of circulation and the degree of unsaturation of capillary blood would be a better index. To investigate this, a determination was made of the relative amounts of oxygen removed from the blood in passing through the tissues before and during anesthesia, by deter- mining the oxygen content of arterial and venous blood drawn at the same time. The amounts removed varied considerably both before and during anesthesia as shown in Table V, but show no striking differences. If the blood flow through the tissues were greatly reduced, one would expect more oxygen to be removed in passage through the tissues unless ether prevented the utilization of oxygen.


The possibility of ether influencing the diffusion of oxygen seems to be ruled out by the fact that the diffusion from the lungs to the blood is not interfered with. It would seem probable from these figures that the oxygen supply to the tissues is not interfered with and that the accumulation of lactic acid during ether narcosis is an

TABLE V.

Comparison of O2 Content of Venous and Arterial Bloods Drawn as Nearly at the Same Time as Possible.

The venous sample was always drawn first, the arterial immediately following. Blood pressure recorded from carotid artery.

Time.

a.m.

8.40 8.55

9.10 9.30

9.40

11.00 11.10 11.27 11.35 11.40

p.m.

12.20 12.30 12.40

Source of blood.

Femoral artery and vein. “ “ ‘I external

jugular. Femoral artery and vein. Anesthesia started. Trache-

otomy. Attached to ether apparatus

120 mg. per 100 cc. blood. Carotid and internal jugular. Femoral artery and vein. Carotid and external jugular. Femoral artery and vein. Ether concentration increased

to 160 mg. per 100 cc. blood.

Femoral art,ery and vein. Carotid artery and jugular vein Right and left heart.

1

1

B 0 F2

mm. HQ

120 120 120 150

120 110 100

-

20.21 14.71 5.51 16.8

140 20.3 16.3 4.0 140 20.1 12.2 7.9 18.3

140 19.4 16.3 3.1 39.3 140 18.2 13.6 4.6 140 19.0 15.1 3.9 160 18.6 12.3 6.3 45.6

160 16.2 12.1 4.1 180 16.4 13.1 3.3 63.8 150 15.8 9.4 6.4

effect of the ether on the tissues themselves or possibly on the cen- tral nervous mechanism as is commonly supposed to be the case in the production of hyperglycemia of anesthesia.

In a preliminary attempt to locate the source of lactic acid, the content of blood passing through the leg and through the


liver was determined. The blood from the femoral vein in each of four samples analyzed contained from 10 to 16 mg. more lactic acid than arterial blood taken at the same time. Blood from the hepatic vein showed no such increase over the arterial blood drawn simultaneously. The hepatic venous blood did show an increase in glucose content which suggests a disturbance in hepatic function. The results obtained from hepatic blood cannot be relied on since, even exercising the greatest care, drawing blood from the hepatic vein involves some manipulation of the gastro- intestinal tract and pressure on the liver. This can be reduced to a minimum by raising the animal to a vertical position and allowing the abdominal viscera to drop of their own weight. If the liga- ments holding the liver in place are clipped, it falls down leaving the hepatic vein exposed. The fact that the glucose content of the blood went up markedly when this part of the experiment was done would make it impossible to draw conclusions. This, however, did not influence the results on blood from the leg since these were obtained before operative procedures were commenced. In so far as these results can be relied upon the source of the lactic acid is the muscular tissues.

If Embden’s (1922) idea that “lactacidogen, ” a hexose phosphoric acid, is the precursor of lactic acid, is correct, the findings of Stehle and Bourne (1924) showing a loss of phosphoric acid from the muscle and our findings showing a production of lactic acid by the muscle, might be interpreted as a breaking down of “lactacidogen” with a consequent throwing into the blood stream of both lactic and phosphoric acids. The phosphoric acid is taken out by the liver, but the lactic acid remains in the circulation, thus accounting for the greater part of the lowering of the alkali reserve. These observations call to mind those of Embden, Griesbach, and Schmitz (1914) showing that nearly equimolecular amounts of phosphate and lactic acid are produced in muscle juice. Too close an analogy cannot be drawn between these two observations until more quantitative work has been completed.

Since muscle tonus is reduced under ether, the normal production of lactic acid should also be reduced. From the fact that the amount given up to the blood increases, wemust conclude, as already pointed out, either that there is an abnormal production not due to tonus nor to muscle activity, but due to the effect of ether,


or else that, due to ether the oxidation of what little is produced is very markedly inhibited and is, therefore, not rebuilt into glucose or other precursor. If, in the normal restoration of lactic acid in the muscle, the phosphoric acid is retained, as oxidative removal of the lactic acid takes place, the fact that it is not retained during anesthesia might indicate that the muscle is producing unusual amounts of lactic acid. If, however, the phosphoric acid is normally excreted, as it is in anesthesia, then the presumption is that the normal production is taking place, but with subnormal oxidative restoration. The increased excretion of phosphates after exercise (Embden, Grafe, and Schmitz (1921)) suggests the latter explanation. If the fall in heat production is responsible for decrease in temperature commonly noted in animals under anesthesia, accompanied as it is by an increase of lactic acid, this points to subnormal removal of lactic acid.

CONCLUSIONS.

1. Accumulation of lactic acid accounts in a large part for the acidosis of ether anesthesia.

2. Its increase is independent of CO2 tension and produces the changes in pH rather than being itself controlled by pH as stated by Anrep and Cannan.

3. Decreased oxygen supply to tissues does not account for its production.

4. The source of lactic acid seems to be the muscle tissues. 5. Production of lactic acid in the muscle, together with loss

of phosphate from the muscle (Stehle and Bourne), during anesthesia, points to a breakdown of scme hexose phosphate, such as Embden’s “ lactacidogen. ”


Protocols of Experiments.

Experiment I.

Moderate Anesthesia.

Female dog. Weight not taken. Very fat. Impossible to get initial sample due to small arteries and struggling. Ether started 10.00 a.m. First sample taken 2 minutes after cone applied. Violent struggling for about 2 minutes. Tracheotomy. Attached to ether apparatus. Sample 4 lost for blood gas determinations. Bleeding from the carotid artery. Total loss of blood 65 cc.

Time.

la.??&.

10.02 10.40 11.30

p.m. 12.00

-

No.

1 2 3

4

Ether.

%E,“. ?%::r 122 51.8 126 50.9 120 58.9

128 66.0

Total CO1 aa drawn.

PH

7.32 38.1 7.18 41.5 7.10 36.6

7.12

3 I .ga d or! r-l mm. Hg

39.8 58.3 59.9

-

6 o? . .

;i 8 28 s .m oa

8 a v G

g.2 V -- -

001. per “HT.

uol. Per

cent cent 35.5 38 36.t 35.8 40 34.1 26.6 38 26.l

CO, o~fepillbrsted T _

. .

3 5 a

-

G d $ ‘2

g 4 v v

-- vol. 001. Per Per

cent cent

15.8 21.2 17.7 19.8 14.4 19.9


Experiment II.

Effect of Variable Anesthesia.

Male dog. Weight 13.2 kilos. Initial bleeding 9.20 a.m., very little struggling. Ether started 9.30 a.m. Animal under in 2 minutes. Trache- otomy. Ether apparatus attached to animal within 10 minutes. Apparatus not adjusted correctly. Concentration of ether was increased during the last half hour. The respiration was depressed, but not enough to cause any difference in the saturation of the blood. Total loss of blood 120 cc.

Time.

a.m.

9.20 9.40

10.00 10.30

p.?n. 12.30 2.00 3.45

-

--

-

No. Ether. Lactic acid.

-

r 1 ng. per too cc.

108 132 145

21.5 7.36 46.7 7.24 68.4 7.19 48.5 7.27

5 135 54.2 7.10 6 160 59.6 7.02 7 164 72.1 6.97

-

_

-

vol. per cent

45.1 42.E 36.c 36.E

33.: 31.5 29.:

:1 I -

43.6 37.5 33.5 41.0 18.016.5(?) 53.1 35.6 37.5 36.0 19.519.9 51.0 33.7 41.0 31.8 15.819.3 42.6 37.3 44.0 34.8 17.818.3

56.4 28.8 37.2 28.9 18.218.8 62.3 25.3 37.5 25.1 18.418.8 62.8 22.2 37.0 22.5 18.218.3


Experiment III.

High Ether Concentration Due to Lipemia. Ether Tension Remained Constant.

Female dog. Weight 13 kilos. Dog playful to begin with, no struggling before taking the initial sample. Ether started 9.00 a.m., drop method. Severe struggling for about 1 minute. Tracheotomy. Attached to ether apparatus 9.15 a.m. Blood showed a progressive lipemia accounting for the increased concentration at same tension. Final distribution ratio 1: 18.5. Samples 4 and 5 from carotid artery. 100 cc. of blood lost.

Time. NO. Ether. %i! PH

a.m.

8.50 9.04 9.20

10.07 10.45

130 158 189 213

Lost 7.43 41.5 7.38 51.5 7.36 69.2 7.20 75.2 7.14

-

-

. . j .j !3 v z ~-

vol. per “H cent 43.2 35.7 46.5 42.5 39.2 37.C 32.8 44.4 34.1 52.1

COZ of equilibrated sample.

Oxygen chemically bound.

42.7 34.3 44.5 42.8 33.2 44.C 39.8 39.2 39.5 27.1 33.2 29.5 29.8, 36.1 30.5

-

5 i ‘s 9 V V --

ad. P-3.

vol. per cent cent

19.820.6 17.119.7 19.5 17.8(?) 19.221.1 20.921.2


Experiment IV.

Very Deep Anesthesia.

Male dog. Weight 10.64 kilos. Initial sample 9.05 a.m. Ether started 9.10 a.m. Cone placed over nose of dog till respiration stimulated. Ether then poured on mask. Unconscious in 4 minute, when mask was loosened to increase ventilation. Tracheotomy. Dog attached to ether apparatus. Anesthesia deep after the first 20 minutes of experiment. Respirationpara- lyzed in 4 hours and 20 minutes. 150 cc. of blood lost.

Time. No.

--

o.m.

9.05 1 9.14 2 9.35 3

10.17 4 11.00 5 11.45 6

p.m. 12.50 7

1.30 8

-

1

.-

,

-

-

Ether. I

160

-

>actic acid. PH

‘Ol. per cent

13.1 7.30 36.2 16.2 7.29 36.8 14.4 7.32 31.5 38.8 7.18 26.2 48.2 7.12 29.7 53.6 7.08 28.7

62.3 76.2

7.05 29.3 54.0 22.2 37.8 22.2 20.3 21.2

- I(

mm. Hll

39.5 41.3 33.1 36.9 47.4 44.9

33.3 35.8 34.2 18.3 21.3 34.7 37.9 34.2 19.8 21.4 33.4 36.0 34.2 19.9 21.1 25.8 36.0 27.0 21.1 21.0 25.5 35.7 26.2 20.1 22.1 22.9 35.9 23.7 20.1 21.1

E. Ronaoni, I. Koechig, and E. P. Eaton 487

Experiment V.

Moderate Anesthesia for 2 Hours and Recovery.

Dog I. Weight 11.2 kilos. Initial sample of blood 9.20 a.m. Cone placed over nose 9.25 a.m. After 1 minute ether poured on. Fully unconscious at the end of the 2nd minute when the cone was replaced by several layers of gauze, soaked with ether. Marked but brief struggling. Ether off at 11.35 a.m. Vomiting in 15 minutes. Lasted only short time. Total loss of blood 150 cc.

a.m.

9.20 10.05 11.30

. . 12.:: 2.30

24 hrs. later.

5 hrs. later.

20 hrs. later.

1 2 3

4 5 6

7

8

-

-

II

ti .a G

ma.

Kc.

122 128

28

m a m?.

IC’CC 16 46 53

7.3: 7.21 7.0!

32 7.2~ 35 7.2: 19 7.2;

16 7.2!

17 7.3:

I CO* of equilibrated I sample.

4 8 8 ‘ij ‘I

B s P -- d. mm. per Hg cent 37.9 38.4 34.2 45.1 32.4 55.c

ool. per cent 25. ES(?) 51.7 27.4

27.5 33.t 25.8 32.9 41.1 31.0 36.3 41.: 35.0

46.9 52.t

38.2 40.:

40.5

37.4

-

-

-

mm. H!J

33.! 5 35.: 7 34.: 2

35.: 2 34.t 3 38.’ 1

38.’ 7

38.a 4

-

vol. PW

cent

37.f 32.: 28.c

29.c 31.1 34.:

4O.C

37.t

- I Oxygen

chemically bound.

-

!A f .$ B d s 6 -- vol.

Per cd. per

cent cent

19.3 20.6 19.8 20.5 18.6 21.7

19.2 19.3 17.5 18.9 17.3 18.4

18.0 18.4

17.9 18.4


Experiment VI.

E$ect of Low Oxygen Tension. Recovery Followed.

Dog I. Second experiment. Weight 11.6 kilos. Initial bleeding 9.10 a.m. Cone placed over nose of dog till respiration stimulated. 9.15 a. m. Ether started. 9.20 a.m. Respiration stopped. Artificial respiration. Mask used throughout experiment. Tendeqcy for respiration to be stimulated due t.o increased COZ. Ether stopped at 11.20 a.m. Total loss of blood 150 cc.

Time.

a.m.

9.10 11.20

p.m. 1.15 2.45 5.15

Next day. a.m.

9.30 p.m.

4.20

NO.

Ii 4 w ;c 00 CC

1 2 126

2 s .I! d 3 mg. Per

!OOcc.

21.f 63.1

3 4 5

54.c 21.:

6 24.:

7 31.t

-

5

) -

G . 3 ._ fz

x, g E

vol. per “H”, cent

7.33 41.8 42.c 7.08 38.3 65.:

7.08 33.1 57.: 7.18 32.2 45.4 7.26 39.3 46.:

7.28 39.8 45.4

7.40 29.5 26.:

302 ofs;q&;;brated Oxygen chemically

bound.

39.1 37.2 39.4 15.3 18.0 24.6 38.7 24.0 8.1 19.8

23.1 35.7 24.0 15.9 19.6 27.8 37.6 28.0 15.8 17.1 36.3 37.2 35.7 16.5 18.2

35.6 37.2 35.2 16.0 17.9

37.9 36.4 38.0 18.9 18.6


Experiment VII.

Effect of Low Oxygen Tension. Recovery Followed.

Dog I. Third experiment. Male. Weight 11.3 kilos. Initial sample 8.50 a.m. Cone placed tightly over nose till respiration stimulated. Ether started 9.05 a.m. 3 minute of struggling. Mask was used throughout the experiment. Even though it fitted loosely over the nose the 02 unsaturation of the blood shows reduced 02 tension. 11.05 a.m. Ether stopped. Loss of blood during 1st day of experiment 180 cc. 2nd day 15 cc. Sample 10 taken with considerable struggling.

Time. No.

&??a.

8.50 9.10 9.20 9.39

10.08 10.35 11.05

. . 12.0; 4.00

Next day. a.m.

10.00

c al 2 --

m. P-W

100 cc.

1 2 120 3 4 125 5 6 7 120

8 9

10

.-

1

-

mg. KC 18.! 24.! 27.! 33.f 65.t 5s.t 82.!

78.! 22.t

35.! -

m a

7.31 7.2: 7.14 7.U 7.0: 7.01 7.m

7.ot 7.3

7.31

2 “0 .- i; % 6 r” -- d. per 7HZ’ cent 38.6 41.1 38.4 49.; 40.5 59.1 41.4 68.: 35.6 65.: 28.3 51.t 26.7 50.:

L 33.7 35.3 36.0 15.7 19.1 7 33.4 37.3 33.2 15.9 19.0 i 31.1 35.3 32.1 15.7 19.2 ! 28.0 36.1 29.8 9.9 19.6 3 24.2 34.3 25.5 11.2 20.0 3 22.9 34.9 23.5 16.3 20.2 3 22.4 35.7 23.0 16.6 19.6

25.9 46.; 7 22.6 37.8 22.1 19.9 19.7 34.5 34.f 5 36.6 37.9 36.6’ 20.1 20.7

40.0 42.j 3 35.8 37.5 36.0 15.6 18.5

CO* ox-;Gi;brated Oxygen chemically

bound.


Experiment VIII.

Dog. Male. Weight 12.2 kilos. Initial sample 8.50 a.m. Ether started 9.05 a.m. Tracheotomy. Attached to ether apparatus 9.10 a.m. Con- centration kept constant. Respiration depressed. Animal dies of respiratory failure 10.30 a.m. Loss of blood 70 cc.

Time. NO. Ether.

--- a.m. 7% r

8.50 1 9.35 2 183

10.05 3 189 10.30 Dead.

I I I hY&en

chemically bound.

vol. ml. Per Per

cent cent

26.4 29.6 18.7 30.3 18.8 29.9


Experiment IX.

Mild Anesthesia. Recovery Followed.

Dog II. Male. Weight 14.3 kilos. Initial sample 8.46 a.m. Mask placed over nose till respiration stimulated. Ether started, 8.50 a.m., without more than 4 minute struggling. Mask replaced by gauze, drop method of administration continued. Salivation marked. Animal choked before Sample 2 was taken. Ether stopped 11.06 a.m. During recovery vomited frequently; due to swallowing of ether with saliva. Vomitus consisted largely of saliva. Loss of blood 150 cc.

Time.

a.m.

8.40 9.20 9.50

10.50 . .

12.0; 2.00 4.00

Next day a.m.

9.00

-

NO.

!ii

2 --

ml. Per

100 ct

1 2 100 3 115 4 110

5 6 7

8

9 s

5 .

.;o .- 8 3

d ; 2

‘2i 8 2.3 ;;g 5 A

.z

s cl m a 2 6: 5 $ ----__-~--

mo. vol. 001. vol. vol.

KEG per Per Per

nol. per cent

“HT. per “H. cent cent cent cent

25.0 7.38 34.0 31.3 33.9 30.5 36.0 21.6 22.7 26.6 7.36 33.9 32.0 29.9 27.3 35.5 22.6 22.4 56.8 7.33 29.2 30.0 31.1 35.8 31.0 22.4 22.1 66.9 7.22 24.1 31.1 24.4 31.0 25.5 21.5 23.2

61.0 7.20 28.7 38.8 26.6 33.5 27.4 21.1 22.2 33.7 7.45 32.3 25.6 35.5 31.6 36.0 20.4 20.4 18.3 7.38 36.9 34.3 35.6 31.6 36.0 18.4 19.7

23.8 7.37 34.4 32.4 36.7 37.4 35.5 20.1 20.1

BIBLIOGRAPHY.

Anrep, G. V., and Cannan, R. K., J. Physiol., 1923-24, lviii, 244. Austin, J. H., Proc. Sot. Exp. Biol. and Med., 1923-24, xxi, 196. Austin, J. H., Cullen, G. E., Hastings, A. B., McLean, F. C., Peters, J. P.,

and Van Slyke, D. D., J. Biol. Chem., 1922, liv, 121. Bishop, G. H., Rep. Sot. C&n. Surg., 36th meeting, May 28-29, 1923, 19. Bohr, C., Skand. Arch. Physiol., 1905, xvii, 104. Clausen, S. W., J. Biol. Chem., 1922, lii, 263. Cullen, G. E., J. Biol. Chem., 1922, lii, 501. Cullen, G. E., Austin, J. H., Kornblum, K., and Robinson, H. W., J. Biol.

Chem., 1923, lvi, 625. Doisy, E. A., Briggs, A. P., Eaton, E. P., and Chambers, W. H., J. Biol.

Chem., 1922, liv, 305.

Ether Anesthesia. III

Embden, G., Klin. Woch., 1922, i, 401. Embden, G., Grafe, E., sndschmitz, E., Z. physiol. Chem., 1921, cxiii, 67. Embden, G., Griesbach, W., and Schmits, E., 2. physiol. Chem., 1914-15,

xciii, 1. Evans, C. L., J. Physiol., 1922, Ivi, 146. Gram&, K., Acta Chir. Stand., suppl. 1, 1922. Haggard, H. W., J. Biol. Chem., 1924, lix, 795. Haggard, H. W., and Henderson, Y., J. Biol. Chem., 1919, xxxix, 163. Leake, C. D., Leake, E. W., andKoehler, A. E., J. Biol. Chem., 1923, lvi, 319. Peters, J. P., Barr, D. P., and Rule, F. D., J. Biol. Chem., 192Q-21, xiv, 489. Ronzoni, E., J. BioZ. Chem., 1923, lvii, 761. Shaffer, P. A., andRonzoni, E., J. BioZ. Chem., 1923, lvii, 741. Stehle, R. L., and Bourne, W., J. BioZ. Chem., 1924, lx, 17. Van Slyke, D. D., and Stadie, W. C., J. BioZ. Chem., 1921, xlix, 1. Van Slyke, D.D., Austin, J. H., and Cullen, G. E., J. BioZ. Chem., 1922,

liii, 277. Warburg, O., and Wiesel, R., Arch. ges. Physiol., 1912, &iv, 465. White, J. C., Arch. Surg., 1923, vii, 347.

Documents

of · 2003-03-19 · demonstrated by Leake, Leake, and Koehler (1923), and by Gram& (1922) who found no acetone during prolonged anesthesias. Leake interprets his findings on acetone