Introduction

General surgical procedures encompass a multitude of surgical types. For the purposes of this chapter, the focus will be on anesthetic considerations for different types of esophageal, abdominal, intestinal, and peritoneal surgery, as well as colorectal surgery. In addition, common surgical techniques used for general surgical procedures to include in open, endoscopic, laparoscopic, and robotic surgery will be discussed.

Laparoscopic General Surgery

Many general surgical procedures lend themselves to a laparoscopic approach and resultant benefits, including smaller incisions, less postoperative pain, shorter recovery times, and reduced postoperative stress response. Typical laparoscopic surgical procedures include cholecystectomy, appendectomy, inguinal hernia repair, esophageal fundoplication, bowel resection, and splenectomy. Laparoscopic-assisted colorectal surgery requires an additional small incision to exteriorize the intestine and access the mesentery to create an anastomosis. General endotracheal anesthesia is utilized for most laparoscopic surgeries and is required for laparoscopic surgeries in the Trendelenburg position to achieve adequate ventilatory control. Use of intraperitoneal carbon dioxide provides insufflation for the surgeon to visualize and to perform surgical maneuvers without the need for extensive incision and exposure. Insufflation of carbon dioxide into the peritoneal cavity, or pneumoperitoneum, results in an increase in intraabdominal pressure and absorption of carbon dioxide. Pneumoperitoneum, coupled with extremes of patient positioning to facilitate surgical exposure, results in predictable cardiovascular and pulmonary physiologic changes (see Table 19.1).

Preoperative preparation for laparoscopic general surgical procedures is similar to that for anesthesia for open general surgical procedures. Focus should be placed on evaluation and optimization of medical conditions that will affect the response to the physiologic changes that occur with the laparoscopic technique and the surgery itself. Induction of general endotracheal anesthesia is achieved with typical induction drugs, as dictated by patient comorbidities, aspiration risk, and airway examination.

Maintenance of general endotracheal anesthesia involves inhalational agents, intravenous agents, or a combination of the two. Standard American Society of Anesthesiologists monitoring applies and invasive monitoring may be indicated, depending upon patient condition, duration of surgery, and expected blood loss. Ensuring adequate intravenous access prior to positioning is necessary if the arms are inaccessible during surgery. The extent of muscle relaxation with neuromuscular blockade depends on the clinical situation and surgical needs. Controlled ventilation is modified to maintain oxygenation (saturation >90%) and normocarbia (end-tidal carbon dioxide 40 mmHg) during insufflation. Intraoperative ventilatory strategies to protect the lungs include tidal volumes of 6–8 mL kg⁻¹ of ideal body weight and 5–10 cmH₂O of positive end-expiratory pressure. Depending on positioning and the degree of insufflation, allowing mild hypercarbia may be necessary to avoid barotrauma. Hypercarbia that does not correct with hyperventilation should prompt suspicion of subcutaneous emphysema (see Table 19.2).

Techniques to improve oxygenation during insufflation include increasing the fraction of inspired oxygen, performing recruitment maneuvers, and increasing positive end-expiratory pressure. Refractory hypoxemia and/or high peak airway pressures in patients in the Trendelenburg position often respond to decreasing the Trendelenburg position or slightly reducing the insufflation pressure.

Laparoscopic surgery typically causes less postoperative pain than open surgical procedures. Use of multimodal analgesia works well for postoperative pain control and minimizes systemic opioid needs. Typical combinations include acetaminophen and nonsteroidal antiinflammatory drugs, in addition to infiltration of local anesthetic at the incision sites by the surgeon prior to emergence. Transversus abdominis plane (TAP) block may be useful in laparoscopic procedures with longer incisions.

Given the high incidence of postoperative nausea and vomiting (PONV) in patients undergoing laparoscopy, antiemetics play an important role in PONV prophylaxis. All patients benefit from intravenous dexamethasone 4–8 mg after induction, and ondansetron administration prior to emergence. For patients with multiple risk factors for PONV, a preoperative scopolamine patch is recommended. Total intravenous anesthesia with propofol is a good option for patients at high risk of PONV who are undergoing laparoscopic surgery.

Laparoscopic surgery may be converted to laparotomy for a variety of reasons. Inability to define the anatomy, presence of dense adhesions, disease acuity, and other surgical conditions may result in conversion to open to complete surgery in a timely and effective manner. In these cases, postoperative pain management includes multimodal analgesia, regional block, neuraxial analgesia, and supplemental intravenous opioids.

Robotic General Surgery

Robotic-assisted surgery has become commonplace in many hospitals. Both robotic and laparoscopic surgery are considered minimally invasive; however, robotic-assisted surgery offers specific advantages over laparoscopic surgery. Robotic systems give surgeons greater control and vision during surgery. Robotic-assisted surgery allows the surgeon to sit at a console equipped with two master controllers that maneuver four robotic arms. The console displays a high-definition, three-dimensional image that allows precise, computer-controlled movements. Robotic arms have the highest level of dexterity, rotating 360 degrees, with flexibility beyond that of the human hand. Robotic-controlled instruments can access areas of the body previously inaccessible. Like with laparoscopic surgery, potential patient benefits of minimally invasive robotic surgery include shorter hospital stay, significantly less postoperative pain, quicker recovery and return to normal activities, smaller incisions, fewer complications, and less risk of infection.

Robotic-assisted surgery is used in a wide range of specialties, including gynecology, urology, gastrointestinal, colorectal, endocrine, cardiac, and thoracic surgeries. Preoperative evaluation and optimization considerations are similar to those used in preparing the patient for laparoscopic surgery. Focus is on medical conditions that affect response to the physiologic impact of robotic-assisted surgery, including extremes of positioning (i.e., steep Trendelenburg, reverse Trendelenburg, and lateral decubitus). General endotracheal anesthesia is necessary for optimal surgical conditions. Patient comorbidities, aspiration risk, and airway examination determine the choice of induction technique.

Maintenance of anesthesia includes a balance of inhaled agents, intravenous agents, or both, along with continuous muscle relaxation to provide safe surgical conditions. In addition to standard monitoring, the need for invasive lines and invasive monitoring depends upon patient condition, duration of surgery, and expected blood loss. Patient positioning and padding require close attention. Patient extremities and shoulders, eyes, and face are of particular concern due to robotic arm movement. Once the robot is docked, there is limited access to the patient. Therefore, proper positioning of the patient and provider access to intravenous lines and monitors must be secured prior to robot docking.

Physiologic changes related to extremes of positioning in robotic-assisted surgery are similar to those in laparoscopic-assisted surgery and often result in exaggerations of common physiologic changes. The addition of carbon dioxide pneumoperitoneum can amplify these changes even more. Techniques to maintain oxygenation and ventilation during robotic-assisted surgery include those used for laparoscopic-assisted surgery.

Postoperative pain management following robotic-assisted surgery includes use of multimodal analgesia to minimize systemic opioid needs. Just like with laparoscopic-assisted surgery, useful medication combinations include acetaminophen and nonsteroidal antiinflammatory drugs, in addition to infiltration of local anesthetic at the incision sites by the surgeon. Regional anesthesia techniques, such as TAP or erector spinae blocks, are options for longer abdominal incisions.

Prevention of PONV with prophylactic agents is important. Risk factors for PONV include female sex, history of motion sickness and/or PONV, nonsmoker, volatile anesthetic use, and need for postoperative opioids. A preoperative scopolamine patch, intravenous dexamethasone 4–8 mg after induction of general endotracheal anesthesia, and ondansetron administration prior to emergence are routinely used for PONV prevention. Total intravenous anesthesia with propofol should be considered for patients who are at high risk of PONV.