Effect of Phrenicectomy upon the Efficiency of Cough and upon Elimination of Lipiodol from Lungs

The removal of a phrenic nerve to paralyze one-half of the diaphragm is now extensively performed in certain cases of pulmonary tuberculosis and in other conditions. Although the literature contains many statements to the effect that cough and expectoration are facilitated by phrenicectomy we have been unable to find any recorded experimental work dealing with such a result. Our experiments show that on the contrary the operation actually interferes with cough and diminishes the elimination from the lung of lipiodol injected into it.

The efficiency of the cough mechanism was measured by the elimination of lipiodol from the lungs before and after phrenicectomy. The rate of disappearance of the oil was determined by means of fluoroscopy and serial roentgen-ray films. Experiments were performed upon 10 dogs. In 2 dogs the time required for the complete disappearance of the oil from the lung was determined. In these 2 dogs a unilateral phrenicectomy was performed after all the oil had disappeared. After they had recovered from their operations the rate of disappearance of lipiodol was again determined and the effect of phrenicectomy upon this rate noted. In 8 dogs unilateral phrenicectomy was performed first and then equal amounts of lipiodol were injected into the right and left lower lobes.

Following the phrenicectomy it was noted under the fluoroscope that some of the oil injected into the lung on the side of the normal diaphragm was coughed up either during the injection or immediately thereafter. Fluoroscopic observations indicated that the cough mechanism was interfered with on the side of the paralyzed diaphragm.