In Reply:-We are pleased to read that Levecque, et al. in their letter confirm our finding that cardiac transplantation patients with preserved cardiac function have minimal hemodynamic alterations after peritoneal insufflation with carbon dioxide during laparoscopic cholecystectomy. [1] It is for this reason that we no longer routinely use pulmonary artery catheters in this patient population. Nevertheless, cardiac transplantation recipients may develop ventricular insufficiency, either from an ongoing disease process or from repeated episodes of rejection. These patients may respond to the physiologic challenge of pneumoperitoneum like other patients with severe cardiac compromise. [2] In this instance, the use of a pulmonary artery catheter could be advantageous in treating the patient, and we would have no hesitation in its use. Of note, at Baylor University Medical Center, a major organ transplantation center, the pulmonary artery catheters used for perioperative monitoring are placed in the operating room under sterile conditions and are carefully monitored by an epidemiologist for bacterial growth and patient infection. The bacterial growth rate on the tip of catheters placed in the operating room is very low and not clinically significant.
Although measurement of pleural pressures may have added to our understanding of changes in invasive pressures during pneumoperitoneum, there is increasing evidence that increases in abdominal pressures between 10 mmHg and 15 mmHg increase the venous return as suggested by indices of preload using pulmonary artery catheter and transesophageal echocardiography. [3] Transesophageal echocardiography can be used to monitor hemodynamic changes, however, it is placed only after the patient is anesthetized and does not provide the baseline (preinduction) values of hemodynamic parameters. Further, collection and interpretation of data using transesophageal echocardiography is investigator-dependent. Therefore, we used pulmonary artery catheters to measure the hemodynamic changes in our study.
As pointed out by Levecque, et al., increasing numbers of investigators are reporting the absence of hemodynamic changes during laparoscopic cholecystectomy in healthy patients and in patients with significant cardiopulmonary compromise. [3–5] These controversial results may be related to the differences in the monitoring technique used to measure the hemodynamic changes (e.g., pulmonary artery catheter, transesophageal echocardiography, and radial artery pressure profile). In addition, the differences in the preoperative status of the patient, anesthetic technique, surgical technique (e.g., insufflation in supine position, the degree of intraabdominal pressure and head-up tilt, and the duration of surgery), ventilatory pattern and intraoperative management of hemodynamic responses also may be responsible for the variable results. Therefore, it is necessary that our readers consider these factors when evaluating such clinical studies. Further, future studies should attempt to standardize these confounding factors that may play a significant role in their outcome.
Girish P. Joshi, M.B. B.S., M.D., F.F.A.R.C.S.I.; H. A.
Tillmann Hein, M.D.
Michael A. E. Ramsay, M.B. B.S., F.R.C.A.
Department of Anesthesiology and Pain Management; University of Texas Southwestern Medical Center; 5323 Harry Hines Boulevard; Dallas, Texas 75235–9068
(Accepted for publication March 23, 1997.)
