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After more than 50 years, pneumoperitoneum with carbon dioxide remains the standard for creating a working space for laparoscopic surgery. Although the physiologic problems resulting from CO2 pneumoperitoneum have been well documented, they are becoming more of a concern as older, more debilitated women are undergoing longer, more extensive laparoscopic procedures
After more than 50 years, pneumoperitoneum with carbon dioxide remains the standard for creating a working space for laparoscopic surgery. Although the physiologic problems resulting from CO2 pneumoperitoneum have been well documented, they are becoming more of a concern as older, more debilitated women are undergoing longer, more extensive laparoscopic procedures (Table 1).
Gasless laparoscopy was developed in an effort to reduce the risks and technical limitations imposed by the requirements of an airtight system.
|Table 1. Physiologic Problems Associated with CO|
|Extraperitoneal insufflation (subcutaneous emphysema, pneumomediastinum)|
To gain a better appreciation of this new technique, it is first important to understand the physiologic alterations induced by the CO2 pneumoperitoneum.
The following changes pertain to normovolemic patients without cardiopulmonary compromise. The increase in intra-abdominal pressure caused by CO2 pneumoperitoneum raises central venous pressure and resistance, and leads to a reduction in venous return and cardiac preload. This effect can be offset by placing the patient in the Trendelenburg position. There is a slight reduction in stroke volume; but with the increase in heart rate, cardiac output is maintained. The higher intra-abdominal pressure also raises the arterial resistance and pressure, thus resulting in an increase in mean arterial pressure.1
The high intra-abdominal pressure reduces renal cortical perfusion by about 60%, with a resultant decrease in urine output.2 This requires vigilance on the part of the anesthesiologist so as not to induce fluid overload in response to oliguria. High intra-abdominal pressure also causes peripheral venous stasis as a result of increased central venous pressure and resistance. Therefore, the use of pneumatic compression stockings is advisable.
|Table 2. Comparison of Gases Used for Pneumoperitoneum|
|Solubility (ml per 100 ML of water)|
|Uses standard insufflator?|
|Hazardous to personnel?|
|Delivered at room temperature?|
No (15 C)
Pulmonary Function Changes
The increased intra-abdominal pressure and volume limit diaphragmatic excursion. This leads to increased peak inspiratory pressure and reduced pulmonary compliance and lower functional residual and vital capacities. Carbon dioxide absorbed through the peritoneum can cause hypercarbia and respiratory acidosis if compensation through increased ventilatory rate (minute ventilation) is inadequate.1 Indeed, fetal acidosis has been associated with CO2 pneumoperitoneum in a ewe model.3
Carbon dioxide has been favored for pneumoperitoneum because of its high solubility in blood (which reduces the risk of gas embolism) and the fact that it does not support combustion. Its disadvantages include the potential for hypercarbia from absorption and for postoperative shoulder discomfort. It has been theorized that carbon dioxide is converted to carbonic acid on the moist peritoneal surfaces, thus irritating the diaphragm and leading to referred neck and shoulder pain. Several other gases have been evaluated for creating a pneumoperitoneum, but each has unique disadvantages in addition to the problems associated with pneumoperitoneum in general (Table 2).4
Figure 1. Equipment for Gasless Laparoscopy
|The Laparofan is connected to the Laparolift, which attaches to the side of the operating table. From Chin AK, Moll FH, McCord MB, Reich H. Mechanical peritoneal retraction as a replacement for carbon dioxide pneumoperitoneum.|
|The Laparofan is in place with the laparoscope behind(cephalod); no trocar sleeve is needed.|
Several studies on various devices for gasless laparoscopy have been published in the general surgical literature. Although there has been no lack of ingenuity for entering and suspending the abdominal wall, studies comparing gasless laparoscopy with pneumoperitoneum are limited.
To date, the only commercially available device is the Laparolift (Origin Medsystems, Menlo Park, CA; Figure 1A). It consists of an adjustable arm that is attached to the side of the operating table and sterilely draped. The surgeon can raise and lower it electronically. The arm is connected to the Laparofan, a disposable sterile device with two metal blades (available in 10- and 15-cm lengths) that are inserted through the umbilical incision in an overlapped position. The blades are then splayed out and locked into a V by tabs on the plastic handle, which is fixed to the end of the adjustable arm. The maximum lifting force of 13.6 kg is equivalent to a pneumoperitoneum pressure of 15 mm Hg.5 The laparoscope is inserted through the same incision, cephalad to the Laparofan (Figure 1B).
A randomized, crossover study of laparoscopy in eight pigs found an increase in mean arterial, central venous, and peak airway pressure as well as end-tidal PCO2 and respiratory acidosis with CO2 pneumoperitoneum in comparison with the Laparolift. The CO2 pneumoperitoneum group also had a decrease in PaO2, but mixed venous oxygen saturation and oxygen consumption were unaffected. The only change in the gasless group was mild respiratory alkalosis.6
We performed a randomized study of 57 patients undergoing laparoscopy for various gynecologic procedures with CO2 pneumoperitoneum or the Laparolift. Minute ventilation, peak inspiratory pressure, end-tidal PCO2, and diastolic blood pressure were lower in the gasless group; these differences were statistically but not clinically significant. There were no differences in systolic blood pressure, heart rate, or core temperature. There were also no significant differences in postoperative pain or nausea.7 The role of carbon dioxide in causing postoperative shoulder pain is further questioned, as a randomized study of pneumoperitoneum with carbon dioxide versus nitrous oxide for laparoscopic sterilization under local anesthesia found no differences in intra- or postoperative pain.8
We experienced greater technical difficulty due to impaired visibility from bowel in the pelvis with the lift device.7 Of the 28 patients in the gasless group, 6 required conversion to pneumoperitoneum because of impaired visibility with the lift device. A randomized trial of CO2 pneumoperitoneum and the lift device for tubal ligation was terminated prematurely after only 18 patients because of the increased technical difficulty due to poorer visibility.9 Of the 10 Laparolift patients, 4 required conversion to pneumoperitoneum to complete the procedure. The operative times were doubled (from 28 to 56 minutes), and postoperative pain and nausea tended to be higher in the Laparolift group. The pneumoperitoneum group had a statistically significant but clinically insignificant increase in peak inspiratory pressure and end-tidal PO2.
In a study of laparoscopic myomectomy, all three cases attempted with the Laparolift were abandoned because of poor visualization.10 Although the procedure was successfully completed in the next 14 patients with an airlift balloon retraction device (also by Origin) connected to the lift device, the investigators noted that current systems for gasless laparoscopy need improvement before they can be used routinely.
There are several reasons for the compromised visibility with the lift device. It elevates the lower abdomen as a truncated pyramid rather than elevating the entire abdomen as a dome as with pneumoperitoneum. That leaves less working room laterally. Also, exposing the cul-de-sac and ovarian fossae can be difficult owing to the presence of bowel. Because the upper abdomen is not elevated, there is less space for the bowel to occupy. Also, the pressure from the pneumoperitoneum further compresses and displaces the bowel from the pelvis.
Another potential advantage of gasless laparoscopy is that, because airtight seals are no longer required, conventional laparotomy instruments can be used. In a case series, the authors placed the Laparofan through a 2- to 3-cm infraumbilical incision and created 1- and 2-cm ancillary trocar sites.11 As it was felt that cosmesis was important, we placed the Laparofan through a 1.5- to 2-cm intraumbilical incision and used 5- or 10-mm ancillary trocars. For the few cases in which conventional instruments were used, they were inserted through 10-mm, valveless plastic trocar sleeves that were incised throughout their length. Nonetheless, it was frequently difficult to open the instruments because of the location of the fulcrum. Instruments with the fulcrum located closer to the handle could be developed, but they would lose the advantage of widespread availability.
Recent animal studies suggest that CO2 pneumoperitoneum, but not gasless laparoscopy, promotes intraperitoneal dissemination and implantation of tumor cells.12,13 Thus, gasless laparoscopy may be a better surgical approach for patients with intraperitoneal malignancies. This technique may also be safer in pregnant patients and those with compromised cardiopulmonary status. Some surgical procedures may also be better suited for gasless laparoscopy than others. Procedures in which bowel is unlikely to obscure the visual field (e.g., cholecystectomy, herniorrhaphy, resection of anterior myomas, and Burch colposuspension) could be managed with gasless laparoscopy. Gasless laparoscopy would also have an advantage for laparoscopically assisted vaginal hysterectomy because visibility could be maintained following the colpotomy incision, but it may be technically difficult to identify the ureters and divide the uterine vessels.
The physiologic changes associated with CO2 pneumoperitoneum are well tolerated in healthy patients but may result in life-threatening cardiac arrhythmia, myocardial infarction, cardiac failure, or pulmonary insufficiency in compromised patients who cannot com- pensate for these alterations. A gasless approach could provide an added margin of safety for these patients as well as for pregnant patients. Patients undergoing laparoscopic surgery for malignancy or laparoscopically assisted vaginal hysterectomy may also benefit from gasless laparoscopy. Another potential advantage of gasless laparoscopy is the ability to use continuous suction and conventional laparotomy instruments.
However, studies to date have demonstrated that surgical procedures with gasless laparoscopy are technically more difficult than those performed with pneumoperitoneum owing to impaired visualization from bowel in the pelvis. Resulting longer operative times, as well as the cost of the Laparolift and the disposable Laparofan, may increase the cost per case. Also, gasless laparoscopy conferred no advantage in terms of reducing hypothermia or postoperative pain or expediting return to activity to justify its routine use in low-risk patients.
As with any new medical device, the initial enthusiasm over gasless laparoscopy has been tempered by actual clinical experience. However, because gasless laparoscopy still promises significant advantages over CO2 pneumoperitoneum, it is anticipated that interest in this technique will continue with improvements that will eliminate the current limitations to its use.
1. Wolf JS, Stoller ML. The physiology of laparoscopy: basic principles, complications and other considerations. J Urol. 1994;152:294 302.
2. Chiu AW, Chang LS, Birkett DH, Babayan RK. The impact of pneumoperitoneum, pneumoretroperitoneum, and gasless laparoscopy on the systemic and renal hemodynamics. J Am Coll Surg. 1995;181:397 406.
3. Hunter JG, Swanstrom L, Thornburg K. Carbon dioxide pneumoperitoneum induces fetal acidosis in a pregnant ewe model. Surg Endosc. 1995;9:272 279.
4. Reichert JA, Moscowitz A, Reimer S, Boyd H. Argon gas as the distending medium in laparoscopic surgery: a preliminary report. J Gynecol Surg. 1995; 11:233 239.
5. Chin AK, Moll FH, McCord MB, Reich H. Mechanical peritoneal retraction as a replacement for carbon dioxide pneumoperitoneum. J Am Assoc Gynecol Laparosc. 1993;1:62 66.
6. Rademaker BMP, Meyer DW, Bannenberg JJG, et al. Laparoscopy without pneumoperitoneum. Effects of abdominal wall retraction versus carbon dioxide insufflation on hemodynamics and gas exchange in pigs. Surg Endosc. 1995; 9:797 801.
7. Goldberg JM, Maurer WG. A randomized comparison of gasless laparoscopy and CO2 pneumoperitoneum. Obstet Gynecol. 1997;90:416 420.
8. Lipscomb GH, Summitt RL, McCord ML, Ling FW. The effect of nitrous oxide and carbon dioxide pneumoperitoneum on operative and postoperative pain during laparoscopic sterilization under local anesthesia. J Am Assoc Gynecol Laparosc. 1994;2:57 60.
9. Johnson PL, Silbert KS. Laparoscopy. Gasless vs. CO2 pneumoperitoneum. J Reprod Med. 1997;42:255 259.
10. Chang FH, Soong YK, Cheng PJ, et al. Laparoscopic myomectomy of large symptomatic leiomyoma using airlift gasless laparoscopy: a preliminary report. Human Reprod. 1996;11:1427 1432.
11. Smith RS, Fry WR, Tsoi EKM, et al. Gasless laparoscopy and conventional instruments. The next phase of minimally invasive surgery. Arch Surg. 1993;128: 1102 1107.
12. Bouvy ND, Marquet RL, Jeekel H, Bonjer J. Impact of gas(less) laparoscopy and laparotomy on peritoneal tumor growth and abdominal wall metastases. Ann Surg. 1996;224:694 701.
13. Mathew G, Watson DI, Rofe AM, et al. Adverse impact of pneumoperitoneum on intraperitoneal implantation and growth of tumor cell suspension in an experimental model. Aust NZ J Surg. 1997;67:289 292.
Jeffrey M. Goldberg, MD, is Director of the In Vitro Fertilization Program and Tommaso Falcone, MD, is the Section Head, both in the Section of Reproduc-tive Endocrinology and Infertility, Department of Gynecology and Obstetrics at The Cleveland Clinic Foundation in Cleveland, Ohio.
Originally published in The Female Patient -- February, 1998
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