Bronchospirometry and Blood Gas Studies after Unilateral Tube Breathing

¹ Professor of Chest Diseases, Cairo University Medical Faculty

Repeating bronchospirometry after tubing the diseased lung, thereby adding a dead space volume of 600 milliliters gave valuable information on the compensatory efforts of the healthier lung to cope with accumulated CO₂ retained by unilateral tube breathing and revealed also further changes in O₂ uptake by individual lungs. The effects of tubing on blood CO₂ content and O₂ saturation were also studied while the patients were breathing room air. An arterial blood sample taken five minutes after the onset of the procedure gave an index of CO₂ clearance by the diseased lung, while that taken 15 minutes later showed the compensatory capacity of the nontubed lung to wash out the excess CO₂. The knowledge of this capacity of the nontubed lung is of importance in certain postoperative states. It is proposed to adopt this method following any conventional bronchospirometry in view of the valuable information added to that offered by routine bronchospirometric technique.