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Page 2 of 10 Arslan et al. Mini-invasive Surg 2018;2:4 I http://dx.doi.org/10.20517/2574-1225.2017.31

Although the aim of the procedures and the results obtained with the application of laparoscopic surgical
techniques seem similar, the physiological effects of laparoscopy are very different from open surgery;
[1,2]
therefore minimal invasive surgery certainly requires a specific anesthetic management . For laparoscopic
and robotic assisted laparoscopic operations, pneumoperitoneum is essential to provide the working
area. The most common gas to provide the pneumoperitoneum is carbon dioxide (CO ). The metabolic
2
profile created by the absorption of CO gas and the effect of abdominal or retroperitoneal high pressures,
2
especially on the respiratory and circulatory system, can compromise the anesthetic management of
[3]
laparoscopic procedures . This becomes even more complicated in operations where steep Trendelenburg
position is combined, such as robotic radical cystectomy and robotic radical prostatectomy. Combination
of pneumoperitoneum with steep Trendelenburg position in these operations may increase the risk of
[3-5]
hemodynamic, respiratory and hemostatic disorders . In order to provide the proper management of the
patient undergone a laparoscopic or robotic assisted laparoscopic surgery and avoid the complications; one
must thoroughly understand the effects of CO pneumoperitoneum and Trendelenburg position.
2

PATHOPHYSIOLOGICAL EFFECTS OF PNEUMOPERITONEUM AND TRENDELENBURG
POSITION DURING LAPAROSCOPY
For an adequate working space and exposure to the target area of the operation, initially pneumoperitoneum
is provided and usually CO gas is used for the procedure. Pressure levels change between 12-15 mmHg in
2
[4]
most cases. However up to 20 mmHg pressures are reported in the literature . CO insufflation is applied
2
through a Veress needle or through a trocar if open Hasson technique is used. In some procedures such as
robotic radical prostatectomy or robotic radical cystectomy, applying Trendelenburg position may also be
mandatory because the intestines might obscure the vision. In order to have adequate exposure; the bowels
must be removed from targeted area of surgery by applying Trendelenburg position. But pneumoperitoneum
(both by increasing the intra-abdominal pressure and by causing hypercarbia) and Trendelenburg position
[5-7]
itself has considerable effects on cardiac, pulmonary, renal and cerebrovascular physiology .
Effects of carbon dioxide absorption
With the beginning of insufflation CO gas starts to fill the cavity where the operation will be carried
2
on. It is highly diffusible in the body and highly soluble in blood. CO exposure may lead to hypercarbia.
2
[7]
Hypercarbia increases with higher pressures and longer exposure times . The respiratory system
is the major way to excrete the CO . Pneumoperitoneum with high intrabdominal pressures and
2
Trendelenburg position may affect the excretion of CO . Therefore, higher CO pressure both increases
2
2
+
the absorption and decreases the exhaustion. The dissolved CO in blood increases H ions and causes
2
acidosis. Hypercarbia and acidosis decrease the cardiac contractility, make myocardium more sensitive
to catecholamines and cause peripheral vasodilatation. But with the sympathetic activation caused
[8]
by hypercarbia it finally leads to tachycardia and vasoconstriction . During laparoscopic or robotic
operations in urology both transperitoneal (TP) and extraperitoneal (EP) techniques are used. Although
both approaches seem to have similar consequences there are minor differences observed during CO
2
insufflation. In their research comparing the effects of CO insufflation on hemodynamics, oxygen levels
2
and acid-base homeostasis in TP vs. EP robot-assisted laparosopic radical prostatectomy (RALRP),
[9]
Dal Moro et al. reported that, EP approach causes a higher absorption of CO , thus a more rapid acidosis.
2
Although in both approaches there were similar operative times and there was even a less extreme
Trendelenburg position in EP approach, EP RALRP was more relevant with CO absorption and acidosis.
2
[10]
A similar study by Meininger et al. also reports that CO absorption was more pronounced with EP
2
approach than TP. However the reasons for these consequences seem to be multifactorial and have not been
[9]
yet clarified .
Pneumoperitoneum and Trendelenburg position
TP approach is frequently preferred in urological surgery as it provides a familiar anatomic perspective
to the surgeon and it is thought to be an easier technique to master at. However, EP approach may also be