Laparoscopic procedures entail intraperitoneal insufflation of carbon dioxide (CO2) to create pneumoperitoneum that allows surgical exposure and manipulation. Carbon dioxide is used because it is noncombustible and more soluble in blood, which increases the safety margin and decreases the consequences of gas embolism. Unlike nitrous oxide (N2O), CO2 does not support combustion and, therefore, can be used safely with diathermy.
The initial access necessary for CO2 insufflation could be achieved either through a blind insertion of a Veress (blunt-tipped, spring-loaded inner stylet and sharp outer needle through a small subumbilical incision) or a trocar inserted under direct vision (avoids dangers of blind insertion).
Upon confirmation of appropriate placement, a variable flow electronic insufflator that automatically terminates gas flow at a preset intra-abdominal pressure (IAP) is used to achieve pneumoperitoneum (maintain the IAP <15 mm Hg because higher pressures can have significant physiologic consequences).
An access port is then inserted in place of the needle to maintain insufflation during the procedure.
A video laparoscope, inserted through the port, allows visualization of the operative field.
Additional access ports are inserted through a number of small skin incisions, which allow the introduction of surgical dissection and suction instruments.
Similar to a laparoscopic procedure, robotic surgery involves development of pneumoperitoneum and placement of video camera (a high-definition three-dimensional vision system) and ports.
This is followed by placement of the robotic arms, a crucial and tedious part of the procedure.
Patient position during minimally invasive surgery varies significantly based on the surgical procedure. (Upper abdominal procedures require a reverse Trendelenburg position, and lower abdominal procedures require Trendelenburg position.) These head-up or head-down positions can be steep.