Ann Thorac Surg 1999;68:32-33
© 1999 The Society of Thoracic Surgeons
Invited Commentaries
Ronald C. Hill, MDa
a Department of Surgery, West Virginia University School of Medicine, Room 4060 Health Sciences Center, PO Box 9238, Morgantown, WV 26506-9238, USA
Invited commentary
Thoracoscopy with carbon dioxide insufflation is performed by many thoracic surgeons. Some utilize single lung ventilation while others do not. Our institution has shown that insufflation utilizating two lung anesthesia causes significant cardiac embarrassment. We have shown using single lung ventilation during thoracoscopy in the pig model, insufflation with carbon dioxide causes cardiac impairment. Ohtsuka and associates have shown that using insufflation of carbon dioxide with single lung ventilation during thoracoscopy in humans caused some changes in hemodynamic parameters. They saw a significant increase in CVP, mean pulmonary artery pressure, and pulmonary capillary wedge pressure at the 5- and 30-min time periods with 8–10 mm Hg pleural pressure. Although it was not significant, the left ventricular ejection fraction tended to decrease. Cardiac index, heart rate, and mean arterial pressure remained unchanged. In doing thoracoscopy, leaks may occur despite the fact that one uses tight-fitting ports. Manipulation of the instruments through the ports can cause the ports to move and subsequently can cause an air leak. In the pig study, we placed purse strings around the ports to ensure a complete airtight seal. Our study in pigs was done on the right side, which is a larger pleural space than the left. Indeed, more gas would be necessary in order to obtain pressures of 5 and 10 mm Hg, and a right-sided compression by direct effect may be more apparent in the pig model. In doing left IMA harvest through a left chest approach, it is possible to enter the mediastinum by taking down the pleura and, therefore, if that were done, the gases and pressures would be distributed not only in the left chest, but in the mediastinum as well. Whether or not positioning of the patient in the right lateral decubitus position versus the supine position for the pig had any significant effect is not known.
We would agree with the authors that anatomical differences between the pig model and the human model may have some bearing on the differences in data. The authors found that rapid insufflation of carbon dioxide into the chest was dangerous and, indeed, they saw a significant reduction of heart rate and arterial pressure with this procedure. When doing it slowly, they saw less dramatic effects, however, they still saw elevation of right-sided filling pressures, as well as a significant increase in the pulmonary capillary wedge pressure and a reduction in the left ventricular ejection fraction by echo after insufflation of carbon dioxide into the left pleura space. We would agree with their statement that "the observed increases in the values of CVP, mean pulmonary artery pressure, and pulmonary capillary wedge pressure were most likely caused by the insufflation of carbon dioxide or artificial positive intrapleural pressure." We do not feel that hypoxic vasoconstriction in the collapsed pulmonary parenchyma would have a major role due to the time period in which the data were collected. Ohtsuka’s paper would, therefore, collaborate our findings of increased right-sided filling pressures as well as some changes in left-sided filling pressures and, although not significant in their paper, a trend toward a decrease in left ventricular ejection fraction. We would agree that most thoracoscopic procedures can be accomplished without insufflation under satisfactory single lung ventilation. If insufflation is mandatory, it should be performed meticulously, as stated in their paper, and consideration should be given to a possible open procedure if deterioration in the patient’s clinical status progresses.
Related Article
-
Hemodynamic effects of carbon dioxide insufflation under single-lung ventilation during thoracoscopy
- Toshiya Ohtsuka, Kazuhito Imanaka, Munemoto Endoh, Tadasu Kohno, Jun Nakajima, Yutaka Kotsuka, and Shinichi Takamoto
Ann. Thorac. Surg. 1999 68: 29-32.
[Abstract]
[Full Text]
[PDF]
