Urological laparoscopy: Basic physiological considerations and immunological consequences

Purpose: The applications of laparoscopy to urological surgery continue to grow at a steady pace. A complete understanding of the physiological and immunological changes associated with pneumoperitoneum is required. We reviewed the physiology of laparoscopy with regard to the major organ systems and summarize the effects of pneumoperitoneum on immune function. Materials and Methods: Articles published in the scientific literature from 1990 to 2004 with relevance to laparoscopic physiology and the immune response to pneumoperitoneum were reviewed using PubMed. Results: Pneumoperitoneum induces predictable pulmonary and renal responses. The cardiovascular and hemodynamic responses are phasic and dynamic in nature, and only generalizations regarding cardiac function can be made. Renal parenchymal and venous compression during pneumoperitoneum are the etiology of oliguria during laparoscopy. The effects are reversible and cause no adverse effects on renal function. There is a general trend toward systemic immune preservation and peritoneal immune depression during insufflation based laparoscopy. Attenuated peritoneal immunity has been demonstrated most consistently by altered macrophage function. Conclusions: Physiological changes incurred as a result of pneumoperitoneum have minimal adverse effects in healthy individuals undergoing laparoscopic surgery. Interest has grown in the impaired peritoneal immune response to CO₂ pneumoperitoneum. Altered intraperitoneal immunity may represent a new avenue for the development of adjuvant therapies for minimally invasive treatments of urological malignancies and for the prevention of port site metastasis. Further elucidation and investigation into the immunological responses to pneumoperitoneum during urological laparoscopic procedures is called for.