Observations placeholder

shortened edited extract from Clinical Results and Physiological Effects of Immobilizing Lung Chamber Therapy in Chronic Pulmonary Tuberculosis - ALVAN L. BARACH, M.D., F.C.C.P.  CHESMORE EASTLAKE, JR., M.D., F.C.C.P. and  OUSTAV J. BECK, M.D.  New York, New York

Introduction

The mechanism by which a normal pulmonary ventilation is produced in patients with  pulmonary tuberculosis without voluntary breathing and without movement of the chest wall was described in 1940. An adequate gas exchange between the lungs and the atmosphere is maintained …by

• equalizing the pressures on both sides of the chest wall - an equal pressure is maintained on the outer and inner surfaces of the thoracic cage and the upper and lower surfaces of the diaphragm
• accurately counterbalancing the resistance in the respiratory passageway from the nose to the alveoli
• varying the density of atmospheric air

Circulatory Effects of Immobilizing Lung Chamber Therapy

Among the effects ..of residence in the immobilizing lung chamber in patients in whom arrest of all chest movement was induced; are

• a decrease in pulse rate of 7 to 20 beats per minute
• a fall in systolic blood pressure of 15 to 20 mm. Hg.
• a fall of diastolic pressure of  5 to 10 mm. Hg.

An analysis of 12 determinations in nine patients tested in this way [showed an] average decrease of 26.8 per cent in the factor used to represent cardiac impact .. as a result of this form of lung rest….. The data ..suggest that a marked reduction in the work of the heart takes place.

The decreased cardiac impact did not appear to be due to interference with the flow of blood but rather, at least in part, to a lowering of the oxygen consumption or the total metabolic work.

The reduction in cardiac impact which takes place in the immobilizing lung chamber is thus not due to damming back of blood into the systemic venous reservoir, as it is in pressure breathing, but presumably, at least in part, to a decrease in total oxygen consumption.

Effects on Serum and Urine Potassium of Residence in the Immobilizing Lung Chamber

A unique character of bodily and mental rest is manifested by patients in whom complete arrest of lung movement takes place……. Since exceptional mental relaxation was observed in patients in the chamber, a study of serum and urine potassium was instituted. In 11 cases of residence in the immobilizing lung chamber for one hour a ..significant increase in serum potassium took. 

This increase is at times as high as 1 milliequivalent.  Elevation of serum potassium is not apt to take place if some degree of lung movement is present.

The decrease in urine potassium excretion after four hours residence in the immobilizing lung chamber, compared to four hours of bed rest, revealed a striking drop in output of potassium, the average decrease being 38 per cent, without, however, a concomitant drop in urine volume.  The decrease in elimination of potassium in the urine was not accompanied by any consistent changes in sodium output in the urine; the mean change was minus 2.3 per cent.

The mechanism of this change in serum and urinary potassium may be related to a lessening of the stimulus to the adrenal gland associated with the decrease of psychic tension produced by cessation of respiratory chest excursions.

Although the precise and full mechanism of decreased potassium elimination in our studies is not completely explained, the inference that it is related to a decreased stimulation of the adrenal gland seems at least a justifiable one from the evidence now at hand.

Clinical and Follow-up Results

The clinical results of recently treated cases, added to those previously reported, indicate that of 29 cases of advanced pulmonary tuberculosis, 19 obtained an arrest of the disease characterized by closure of cavity and negative sputum for periods varying between six months and nine years.

Technique of Operation of the Immobilizing Lung Chamber

The importance of the initial training period of the patient for a week or 10 days has become more and more apparent. In fact, failure to superintend the early management of cases treated with this method may result in failure to achieve continuous arrest of lung movement in patients who would otherwise respond well to immobilizing lung chamber therapy.

The patient who has had good supervision and training during the first 10 days generally manifests no signs of breathing during the remainder of treatment, not less than 10 hours a day for four to five months.

The chamber now in use has been especially air-conditioned and has employed an alternation of pressure above and below the atmosphere. A somewhat changed type of chamber in which 110 volt alternating current can be used is in process of development. The importance of providing a consecutive period of 10 hours during the day or night, interrupted only by meals, will be described.

Discussion

Clinical and physiological evidence now available concerning chamber-induced rest of the lungs would suggest that a more widespread use of this treatment is indicated, not only for advanced cases, but in patients manifesting less extensive disease. In fact, the trial of properly managed immobilizing lung chamber therapy in preference to pneumothorax and thoracoplasty might have the obvious advantages of inducing clinical recovery without impairment of lung function or  structure, and without the risk attendant on other methods of collapse therapy.

The unique mental and physiologic benefits of ventilation without chest movement are revealed by the studies presented in this paper. The decrease in cardiac impact, the lowering of the pulse rate and blood pressure, the lessened excretion of potassium, the increase in serum potassium, the elevation of the T-wave and the indications of decreased total metabolic work, all point to a more restful functioning of the organism than is obtained by bed rest.

Furthermore, no instance of spread of disease has happily taken place in our cases during the period of residence in the chamber.

SUMMARY

1. In 19 of 29 cases of advanced pulmonary tuberculosis, arrest of disease took place as a result of immobilizing lung chamber therapy.
2. Properly regulated immobilizing lung chamber therapy, in favorable cases, has a specific effect on collapse and healing of tuberculous cavities. In no instance in the series of cases observed over a period of 13 years did a spread of disease take place during  immobilizing lung chamber treatment.
3. The physiological effects of living without voluntary breathing, i.e., lung ventilation without lung movement, appear related, at least in part, to the unique quality of bodily and mental rest initiated by elimination of excursions of the chest ordinarily employed in normal respiration.
4. The effects of residence in the immobilizing lung chamber, in cases in which complete arrest of chest movement is produced, include:

A) A marked decrease in cardiac impact. When this observation is interpreted in conjunction with the findings of an unchanged venous pressure, a decrease in pulse rate and blood pressure, the conclusion seems justified that the work of the heart is markedly reduced. In addition, the total energy consumption of the individual would appear to be strikingly diminished.

B) The period of residence in the immobilizing lung chamber is characterized by a decreased excretion of potassium in the urine and an increase in serum potassium. These biochemical responses to respiratory, mental and bodily rest would seem to be the result, at least in part, of a lessened stimulus to the adrenal gland.