The first consideration for pneumoperitoneum is the choice of entry into the abdominal cavity. The most widely used technique is the Veress needle (VN) despite it having a slower insufflation rate and potentially life-threatening complications. The VN may accidentally and undetectably puncture a vessel and lead to occult bleeding into the retroperitoneum or blood pooled away from surgical view due to positioning. A more immediate and catastrophic injury is introduction of the VN into a major blood vessel, resulting in brisker bleeding or a CO₂ embolus . If the rate and volume of intravascular CO₂ is large enough, right heart and pulmonary circulation will be obstructed, which leads to cardiovascular collapse. Similarly, if the insufflation tubing is not first bled of air, which is 78% nitrogen, with CO₂ gas, intravascular penetration could create a lethal nitrogen venous air embolism. A nitrogen venous air embolism is more likely to cause cardiac arrest then a CO₂ embolus because of nitrogen’s much lower solubility in blood. A symptomatic air or CO₂ embolism is treated by placing the patient in the head down left lateral decubitus position (Durant maneuver), administering fluid and inotropic support, and performing chest compressions during low or no cardiac output.

An alternative technique to insufflation with a VN is direct trocar insertion. This technique decreases the opportunities of insufflating areas other than the peritoneal cavity because it is done under direct visualization, but it affords a greater likelihood of extensive subcutaneous emphysema that extends along contiguous fascial planes up to and including the face. Once properly positioned, the trocar can deliver higher a CO₂ insufflation flow rate. A faster insufflation rate has two drawbacks: it increases the likelihood of cardiac bradyarrhythmias and it contributes to the referred pain from pneumoperitoneum. The surgeon should be prepared to quickly desufflate the abdomen in the cases of severe bradycardia or asystole, and the anesthesiologist should consider administering anticholinergic drugs to attenuate the bradycardia and hypotension. In severe cases, low doses of epinephrine are given.

A third approach is the open entry technique, which is typically only used with patients who have undergone previous abdominal operations and who are thus at risk for multiple adhesions. This entry approach includes many of the same insufflation and hemodynamic concerns as the direct trocar insertion approach.

Following the entry of the insufflating device, the surgeon may commence to the target insufflation pressure or briefly exceed the goal in order to place trocars into a maximally dilated cavity.

The goal pressure for creating a pneumoperitoneum has been much debated. The consensus appears to be 12–15 mmHg of pressure. Insufflation pressures of 12–15 mmHg will increase CO₂ absorption progressively throughout the case and require ventilator adjustments to increase the patient’s minute ventilation. Increasing the insufflation pressure to 20 mmHg slightly improves surgical visualization and reduces blood loss by tamponading venous oozing, but these elevated pressures incrementally add risk and increase CO₂ absorption in the patient. Some of these risks include cardiac arrhythmias, lung barotrauma, renal and hepatic hypoperfusion, respiratory acidosis, increased postoperative pain, and postoperative nausea and vomiting. Thus, from a physiologic standpoint and in the Trendelenburg position, pressures above 15 mmHg may be tolerated but should be used conservatively.

Intraoperative fluid management for robotic cases focuses on optimizing the surgical field as well as maintaining appropriate intravascular volume and cardiac output. Robotic urologic pelvic surgery places the patient in lithotomy and/or steep Trendelenburg . These positions significantly augment preload and coronary perfusion pressure. This autotransfusion from the lower extremities limits the need for additional fluid administration and helps offset the caval compression effect of the pneumoperitoneum on venous return. However, over time, the steep Trendelenburg position will increase upper body hydrostatic pressure in the vasculature and cause fluid to leak out of intravascular vessels and into interstitial and extracellular spaces, resulting in facial, orbital, pulmonary, and laryngeal edema. In cases such as prostatectomies and cystectomies, urinary fluid leaking into the abdomen and then suctioned into the suction bucket may lead to an overestimation of blood loss. Absent unusual bleeding, a typical fluid resuscitation during a robotic prostatectomy or cystectomy should range from 1.5 to 2 L of crystalloid solution, with the majority administered after the urinary anastomosis is completed. Additional fluids should be consistent with surgical blood loss and fluid loss due to bowel prep.

The American Society of Anesthesiology (ASA) has specific recommendations for monitoring patients based on the depth of anesthesia provided (Table 4.2). The components of basic monitoring include a noninvasive blood pressure cuff, pulse-oximetry, capnography, temperature monitoring, and electrocardiogram [4].