PHYSIOLOGICAL AND PHYSIOLOGICAL CHEMICAL OBSERVATIONS IN EPIDEMIC INFLUENZA

ByC. C. Guthrie, Ph. D., M. D.

The material consisted of cases in the acute stage of epidemic influenza with and without clinical pulmonary involvement (alveolar); of convalescents, and of normal individuals without influenzal history.

It was hoped that it would be possible to follow selected cases over considerable time periods, observation to compromise coordinated clinical as well as laboratory data, but the exigencies of the situation rendered this impossible. Unfortunately, this limits the value of the studies. But since similar observations were made on cases ranging from normal to the gravest severity—in fact, preceding death but a few hours in some instances—and from the nature of the findings, certain conclusions are clearly warranted.

It is regrettable that the data on certain points is not more extensive, and particularly that other methods of observation were not employed. As an example of the latter, measurements and analyses of expired air may be given, as this was planned from the beginning and unsuccessful efforts made to provide the required apparatus. In view, however, of the circumstances of the investigation, it is felt that the studies made are, on the whole, reasonably comprehensive and complete. And it is only fair here to acknowledge that this was rendered possible by the cordial and practical support of the Medical School, the military authorities, the director of the laboratories, clinical colleagues, particularly Dr. W. W. G. Maclachlan, and last, but not of less importance, of the members of the department who made the studies.

In presenting the results, it is deemed most expedient and practical to omit extensive tabulations and to summarize the data under each subject.

From the report it will be obvious that certain studies were in preliminary stages at the termination of the investigation. Thiswas due in certain instances to the lateness of their undertaking, or time consumed in providing essential equipment and methods; or to disappearance of suitable cases due to waning of the epidemic.

For the most part, cases showing marked clinical symptoms were studied. The pulse in severe cases frequently was weak and rapid but regular. In some cases it was less rapid than the clinical state would seem to indicate.

Arterial Blood Pressurewas low; systolic pressure in severe cases ranging downward from 95, and diastolic down to 40 or under. In patients in early stages of convalescence the pressure showed a marked advance toward normal levels. Arterial blood pressure seemed a reliable general index of the condition of the patient.

Venous Blood Pressure.—The observations included patients who a few hours later expired. The Von Recklinghausen method was used. No marked abnormality was observed, so other methods of observation were deemed superfluous.

In severe cases, frequently it was rapid and of shallow character; but, like the pulse, often it was less rapid than the clinical state would seem to indicate.

Cyanosisof dark hue and marked degree was prevalent in the earlier severe cases, and in some cases appeared entirely out of proportion to the state of circulation and respiration and to the post-mortem findings as reported by Dr. Klotz.

Hemorrhage being not uncommon, the blood was tested for coagulability, but in this respect no marked departure from the normal range was noted.

Coagulation.—Coagulation time was observed by stirring blood in a test tube with a wire and noting the time of the appearance of fibrin and by means of a Biffi-Brooks coagulimeter. The extreme ranges observed were from 2½ to 5½ minutes. Theaverage by defibrination was 3 minutes and 36 seconds, and by the Biffi-Brooks method 4 minutes and 38 seconds.

Red Corpuscles.—Osmotic resistance. A number of bloods were examined by observing their resistance to osmotic laking by exposure to a series of hypotonic sodium chloride solutions. Though some differences were observed, from the evidence obtained, it is not permissible to conclude that such variations were constant or of a significant magnitude.

Coloron exposure to air. It was early observed that venous blood from cyanotic patients was very slow to take on arterial hue on exposure to air.

Plasma Bicarbonate.—The plasma bicarbonate was determined in seven cases by Miss Waddell by the method of Van Slyke and Cullen. In all except one of these the results were within the normal range as given by Van Slyke. Three were in the lower normal range, being 54.1, 55.1 and 60.5 respectively, expressed in terms of cubic centimeters of CO2reduced to 0°, 760 mm. Hg. pressure, bound as bicarbonate by 100 c.cm. of plasma. Three were in the median range, being 64, 65.5 and 71 c.cm. In one case the bicarbonate CO2was reduced to 46.6 c.cm.

There seemed to be no constant relation between the apparent severity of the clinical condition of the patient and the bicarbonate reading. In the one case in which this was found to be reduced below Van Slyke’s lower normal limit the blood was taken only a few hours before death.

Hemoglobin Per Cent.—As determined by the Sahli hemoglobinometer (by Miss Lee) and as estimated by the total oxygen capacity (Van Slyke method) (by Dr. Rohde and Mrs. Macklin), the hemoglobin content ranged within normal levels.

Relative Volume of Corpuscles.—A limited number of hematokrit tests on severe cases gave results in normal levels.

Spectroscopic Studies.—Sera obtained from 20 post-mortem bloods were examined spectroscopically. In eight an absorption band in the red was observed. In some instances such a band was observed in blood obtained shortly after death and before coagulation had occurred, while other similar bloods, as well as bloods obtained at longer intervals after death, exhibited no such band. A similar band was observed in one case from blood obtained from a patient about 12 hours before death from pneumonia following influenza. Medication was not a causativefactor. To ammonium sulphide the band in the red reacted as methemoglobin and the position (as estimated by Dr. Menten) corresponded with methemoglobin. Oxyhemoglobin bands in such bloods occupied normal positions as determined by Dr. Menten. On diluting such bloods with water no abnormality in character or position bands was observed, save in one instance (No. 778 below). This does not, however, disprove the possibility of such abnormality in the hemoglobin within the cells, for moderate dilution only of serum rendered the band in the red invisible, presumably by dilution.

Detailed examination of the absorption bands was made with a direct reading wave-length Hilger Spectroscope (which was calibrated by line spectra derived from salts added to an alcohol flame) by Dr. Menten. This spectroscope had an accuracy of about two Angstroms. In all, seven post-mortem bloods were examined, viz. autopsy numbers 756, 761, 763, 773, 778, 784, and 787. In five of these, sufficient serum was obtained to make readings. All gave the two characteristic oxyhemoglobin bands in the blue-green with centers of the bands atλ758μμλand 542μμ. The second oxyhemoglobin band varied slightly in width in the different samples. In addition to the two oxyhemoglobin bands in each of four of the above sera, viz: Nos. 756, 763, 767 and 787, an absorption band in the red was found with the center of the band as follows: Number 756 atλ627μμ, number 761 atλ634μμ, number 763 atλ625μμ, and number 787 atλ634μμ. These bands varied considerably in intensity and could only be identified when the two oxyhemoglobin bands were merged and appeared as one broad band. As controls for the position of the oxyhemoglobin bands two normal bands were examined, which showed two bands with centers also atλ758μμandλ543μμ. For comparison of the methemoglobin bands of the above post-mortem bloods, a sample of this hemoglobin compound was made by adding potassium ferricyanide to normal blood until the solution became brownish in color. The center of this methemoglobin band was found atλ634μμ. In blood from autopsies number 773 and number 778 sufficient serum could not be obtained to make a reading. To each of these bloods distilled water was added. The laked blood of 778 gave a methemoglobin band with the center atλ632μμon examination 24 hours after autopsy. Similar treatment of corpuscles five days subsequently gave no indication of the presence of any methemoglobin spectroscopically.From the serum and from the laked corpuscles of number 784 no trace of methemoglobin was found when the blood was examined a few hours after removal at autopsy.

From the serum and from the laked corpuscles of number 784 no trace of methemoglobin was found when the blood was examined a few hours after removal at autopsy.

Oxygen Capacity.—The total oxygen capacity was determined by the Van Slyke method (by Dr. Rohde and Mrs. Macklin). At this stage the more pronounced type of influenza had subsided, but in early convalescence the capacity was within normal ranges.

Other studies using different technique gave concordant results, but there were indications that oxygen was more slowly absorbed than normally.

Oxygen Content of Venous Bloodmeasured by the Van Slyke method (by Dr. Rohde and Mrs. Macklin) on the same bloods examined for total oxygen capacity seemed to indicate a mild deficiency as compared to normal bloods.

Gases, Kinds, Quantity and Rate Yielded to Vacuum.—In general it may be said that quantitative differences observed are not considered fundamental, but that the studies indicate abnormal slowness in oxygen absorption.

Gases, Quantity and Rate of Absorption on Exposure to Air After Extraction by Pump.—The results emphasize slowness of oxygen absorption as compared to normal blood.

The material to be examined was exhausted for three minutes in the receiver of the Van Slyke apparatus. One c.cm. was then transferred, with as little exposure to air as possible, to a small empty bottle, which was then closed and placed in communication with a calibrated, horizontal tube, containing a segment of alcohol, which served the dual purpose of a seal and an air volume change indicator. (See Fig. 1.) The apparatus was made in duplicate and mounted on a common base, so that simultaneous readings on different samples could be made. After establishing the zero position of the alcohol segment, the base on which the bottles were mounted was vigorously shaken in a uniform manner. Ten seconds after the period of shaking, the volume readings were taken. Successive periods of shaking and reading were conducted at 30-second intervals, until the test was completed. Actual volume changes were then calculated, tabulated and plotted.The greater confidence is placed on the results obtained by observing the color of the blood, as described below; but since then the method has been checked up and the results indicate that the findings were of sufficient accuracy to warrant their inclusion in this report.[1]

The greater confidence is placed on the results obtained by observing the color of the blood, as described below; but since then the method has been checked up and the results indicate that the findings were of sufficient accuracy to warrant their inclusion in this report.[1]

1. Studies along this line are being made with improved apparatus, the results of which, together with the description of the apparatus, will be published elsewhere. (See Am. Gr. Physiol., 1920, li, 195.)

FIG. 1.

Effect of Addition of Serum on Behavior on Exposure to Air.—The persistence of venous hue of blood exposed to air was noted above. It was observed that the addition of serum from the same blood conspicuously shortened the time required for such blood to acquire an arterial hue. The addition of normal serum was more effective in this respect than pathological serum. Measurements of the rate of absorption of such blood after the addition of serum indicated acceleration of oxygen absorption.From this it would seem that the oxygen transmitting capacity of the serum was diminished.

Effect of Addition of Dry Sodium Bicarbonate on Behavior on Exposure to Air.—The addition of a small quantity of dry sodium bicarbonate to a blood refractory to arterialization on exposure to air enormously accelerated the process, as judged by the color. To what extent the change in color may have been due to causes other than oxygen absorption was not determined.

The most significant positive findings were evidence of deficiency of serum oxygen transmitting capacity or rate, and the detection in serum of an absorption band in the red corresponding to methemoglobin. The presence of the abnormal substance giving rise to the absorption band is considered of special interest as indicating abnormal chemical conditions in the blood, rather than material change in hemoglobin oxygen capacity.

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