Robotic thoracic surgery continues to gain momentum and is emerging as the optimal method for minimally invasive thoracic surgery. As a rapidly advancing field, continued review of the surgical and anesthetic concerns unique to robotic thoracic operations is necessary to maintain safe and efficient practice. In this review, we discuss the intraoperative concerns as they pertain to pulmonary, esophageal, and mediastinal thoracic robotic operations.
Key points
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Anesthetic considerations for thoracic surgery are evolving concomitant with the shift from open to minimally invasive surgery, including the use of robotic systems.
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Successful robotic surgery begins with optimal patient positioning and port placement, which are particular to the planned operating and target anatomy.
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Robotic pulmonary resection is aided by new technologies, including the use of contrast agents to localize pulmonary nodules and define the intersegmental planes.
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Catastrophic events during robotic thoracic surgery are uncommon, but surgeons must be prepared to address them effectively, which may include conversion to open thoracotomy.
Introduction
A robotic approach has been applied to nearly all procedures in the chest, including surgery of the lung, esophagus, and mediastinum, with outstanding short-term outcomes. With this shift in technology, the intraoperative anesthetic and surgical concerns have equally changed. With less surgical stress during minimally invasive surgery, anesthetic monitoring and approaches to pain control have become more conservative. From a surgical perspective, greater visualization of structures on the robotic system has come with the loss of tactile feedback, creating new challenges. In this review, we discuss the intraoperative anesthetic and surgical concerns as they pertain to pulmonary, esophageal, and mediastinal thoracic robotic operations.
Anesthetic management in robotic thoracic surgery
The evolving shift away from open thoracotomy to minimally invasive techniques in thoracic surgery has changed the fundamental anesthetic concerns for these operations. Anesthetic management for robotic lung surgery, is similar to the management of patients undergoing video-assisted thoracoscopic surgery (VATS), typically with general anesthetic technique and controlled, one-lung ventilation.
One-Lung Ventilation
During robotic pulmonary resection, selective ventilation of the nonoperative lung with deflation of the operative lung, or one-lung ventilation, provides a surgical space in the closed thoracic cavity. One-lung ventilation can be attained through several different methods, including placement of a bronchial blocker, although use of a double lumen tube is the most effective and efficient and, therefore, most commonly used method.
Ventilation strategies for robotic lung surgery mirror those for any other thoracic surgery in which one-lung ventilation is used. Preoxygenation with 100% inspired oxygen before lung isolation theoretically decreases the nitrogen concentration of the lungs, facilitating rapid lung deflation via expedient absorption of oxygen. Protective single lung ventilation strategies should be used to prevent barotrauma to the ventilated lung and to avoid postoperative pulmonary dysfunction. Different methods exist to determine the optimal tidal volume and positive end-expiratory pressure to be delivered. Titration of the fraction of inspired oxygen and small increments of positive end-expiratory pressure can be applied to prevent and/or treat intraoperative hypoxia.
Operative visualization is improved with the instillation of carbon dioxide into the operative chest. The pressurized pneumothorax achieves a more rapid and permanent deflation of the lungs when compared with passive deflation. Further, a pressured chest deflects the diaphragm into the abdomen created a wider surgical field. Venous return to the heart may be impeded with high intrathoracic pressure, typically occurring only when the pressure exceeds 5 mm Hg. For this reason, a patient’s blood pressure should always be check immediately after the initiation of insufflation. When hypotension develops, the operation is held and insufflation pressure is decreased until hemodynamics have normalized. Rare occurrences of carbon dioxide embolism have been reported when the system is erroneously placed in the lung parenchyma. Severe subcutaneous emphysema can result when placed in the extrathoracic tissues.
Monitoring and Access
Patient monitoring for robotic lung surgery incorporates the standard American Society of Anesthesiologists monitors: electrocardiogram, pulse oximetry, capnography, and noninvasive blood pressure cuff.
We do not use arterial lines routinely, but place them selectively in patients with severe cardiac morbidity or for anticipated operative complexity. Traditionally, arterial line monitoring was used in the vast majority of thoracic surgical procedures, both owing to the risk of intraoperative blood loss and to monitor blood gasses during 1 lung ventilation. As anesthesiologists have become more experienced with minimally invasive thoracic surgery, the imperative to reflexively place arterial cannulas for these procedures has largely abated. For more complicated cases, including bilobectomy, esophagectomy, reoperative cases, and more invasive surgical procedures with higher potential for blood loss and hemodynamic compromise, it is prudent to place an arterial cannula for beat-to-beat monitoring of the blood pressure and for the ability to draw arterial blood samples for intraoperative analysis.
A single, medium-sized intravenous line is often sufficient for the majority of cases. Venous access with multiple large-bore intravenous lines, or even a central line, is generally unnecessary, but may be considered for difficult operations, which may complicate intraoperative hemodynamic status, such as patients with sepsis from empyema or esophageal preformation. One caveat to the emphasis on minimizing the placement of lines is the challenge of direct physical access to the patient associated with positioning for robotic surgery. Although the lateral positioning is similar to that of VATS and open thoracotomy, the positioning of the surgical robot often limits access by the anesthesiologist to the patient’s arm and face. This can present a challenge if the need for placement of additional venous access or an arterial catheter arises during the course of the surgery. The Xi system is the current edition of the da Vinci robot and provides greater versatility and functionality. The Xi system allows for docking of the robot to the side of the operating table, whereas the Si system requires placement of the robotic cart at the patient’s head. With the greater maneuverability of the Xi, patient access for the anesthesiologist is significantly enhanced.
The incidence of postoperative urinary retention in the literature varies from 5% to 70% and is complicated by the lack of consistent definitions, variance in surgical procedures and populations, and differences in the administration of anesthetic agents. Established risk factors include older age, male sex, type of perioperative and intraoperative anesthetics and analgesics administered, and the type and duration of surgery. The placement of a urinary catheter is infrequently required, except in patients at high risk for postoperative urinary retention (patients with benign prostatic hyperplasia) or when the operation is expected to last more than 3 hours.
Pain Management
In the era of enhanced recovery for surgery, the importance of controlling postoperative pain is critical to decreasing postoperative morbidity, decreasing length of hospital stay, and improving patient satisfaction. Enhanced recovery protocols assist the entire perioperative team in planning ahead and minimizing both the magnitude and duration of patients’ postoperative pain. Crucial to that goal is a well-designed perioperative analgesic protocol. Our preferred preemptive regimen includes acetaminophen and gabapentin, taken orally before surgery. Multimodal analgesia allows for the synergistic combination of drugs with varying mechanisms of action and helps to minimize side effects by requiring lower doses of the individual analgesic agents. Specifically, the combination of preoperative oral medications and intraoperative nerve blockade allows for the minimization of opioid administration, both in the operating room and in the immediate postoperative period. This strategy minimizes opioid-related side effects and facilitates early ambulation and hospital discharge.
The need for invasive pain management procedures, such as thoracic epidural catheter placement or paravertebral blocks, has decreased with smaller incisions and lower postoperative pain experienced by patients after minimally invasive thoracic surgery. Regional anesthetic techniques help to attenuate endocrine and metabolic responses to the stress of surgery, limiting stress-induced organ dysfunction and pain postoperatively. We routinely perform a subpleural paravertebral intercostal block with bupivacaine hydrochloride (Marcaine). Performance of intercostal nerve blockade is done under direct visualization with the robotic camera. Additionally, we instill local anesthetic at each port site in the subcutaneous tissue as a field block. The optimal admixture of local anesthetic for pleural and subcutaneous blockade is controversial. Presently, we do not feel the need for additives above a long-acting local anesthetic, such as epinephrine, steroids, or liposomal bupivacaine (Exparel). Retrospective studies have shown conflicting data regarding liposomal bupivacaine in patients undergoing thoracotomy or thoracoscopy. , In a randomized controlled trial, liposomal bupivacaine marginally decreased postoperative pain and failed to provide an opioid-sparing benefit to patients after sternotomy.
Fluid Management
Administration of large volumes of fluid during thoracic surgery is a contributory, if not causative, factor in the development of postoperative complications. A number of studies have shown that fluid administration of more than 2 L is associated with pulmonary edema and acute lung injury. Our goal is to limit fluid volume to less than 1 L for every thoracic surgery case. Fluid requirements or more than 1 L should prompt a discussion between the anesthesiologist and surgeon regarding the operative plan and hemodynamic status.
Intraoperative Communication
Strong communication between members of the operative team is imperative for safe and efficient robotic surgery. During robotic surgery, the surgeon is positioned on the surgeon console, which is typically distant from the patient and anesthesiologist. Despite amplified microphones and operative speakers, communication between members of the team is inherently less intimate and direct than open surgery at the surgical table. Communication must be clear and concise. To help encourage communication, we do not pin up the surgical drapes at the patient’s head, but allow the sterile field to fall, permitting a clear line of vision between all members of the team. Talk-back techniques to confirm understanding is an effective tool for avoiding errors and miscues. Ambient noise is amplified in the surgeon console and can be distracting. We advise a quiet operating room to maximize team communication, particularly during critical parts of the case. Maintaining a relatively small group of anesthesiologists, physician assistants, circulating nurses, and scrub techs, all of whom are very familiar with the unique elements of robotic thoracic surgery, helps to foster a collaborative atmosphere and to facilitate communication between the members of the team.
Patient and port positioning
Safe and efficient patient position is essential for successful robotic thoracic surgery. Despite the operation performed, care is taken to adequately pad the patient’s arms and legs, using foam positioners, pillows, and blankets to buffer any zone where the patient’s body will be pressed. We attempt to limit the number of support systems used, avoiding the use of beanbags, axillary rolls, or arm boards. The patient is secured to the operating table at the hip, shoulders, upper extremities, and at the legs.
Robotic instruments are inserted via trocars, which are placed between the ribs through intercostal incisions. The arms incorporate remote center technology that anchors the fulcrum of the robotic arms in space, thereby reducing stress to the ribs. Despite the relative stability of the trocars, lateral and pivoting movements of robotic instruments produce pressure on the intercostal nerves, contributing to postoperative pain and dysfunction. To limit nerve trauma, it is important that the robotic trocars are driven straight into the chest, avoiding angulation, thereby limiting pressure on the intercostal nerve. We use a zero-degree camera to continue minimizing the torque placed on the intercostal nerve at the camera port.
Successful robotic surgery also depends on a skilled bedside assistant. Given the coordination required between surgeon, assistant, and the robotic system, a dedicated assistant with familiarity with the conduct of the operation provides continuity and improves efficiency.
The lateral decubitus position is used for robotic pulmonary resection and thoracic mobilization and reconstruction during esophagectomy. A mild degree of flexion is used to increase the space between the intercostal spaces and to displace the hip from the chest, allowing greater range of motion at the assistant port.
Pulmonary Resections
Port sites are initially mapped on the patient to guide placement. The ports are placed in the eighth intercostal space, above the ninth rib: robotic arm 3 (8-mm port) is placed 4 cm from the lateral aspect of the spinous process of the vertebral body, robotic arm 2 (8 mm) is 8 cm medial to robotic arm 3, the camera port is 8 cm medial to robotic arm 2, and robotic arm 1 (12 mm) is placed approximately 8 cm medial to the camera port, avoiding the rectus muscles, just above the diaphragm ( Fig. 1 ). The assistant port is triangulated behind the most anterior robotic port and the camera port. Typically, robotic arm 1 is the “right hand,” which controls a bipolar forceps. Robotic arm 2 is the “left hand” and typically controls a grasper, such as a Cadiere forceps. Robotic arm 4 typically controls a tips-up grasper, which is used for retraction and blunt dissection.
Esophagectomy
During the thoracic phase for robotic esophagectomy, the patient is placed in the left lateral decubitus position with the right chest up and tilted forward to allow the lung to fall away from the posterior mediastinum ( Fig. 2 ). The port for the right robotic arm is marked at the inferior aspect of the right axilla, just below the hairline, medial to the anterior aspect of the scapula. The arm serves as the surgeon’s right hand, commonly used to control a long bipolar grasper or vessel sealer. The robotic camera port is placed 8 to 10 cm inferiorly to the right robotic arm in the same anatomic plane. The left robotic arm port is placed 8 to 10 cm inferiorly to the camera port, in the same anatomic plane. The left hand typically controls a Cadiere forceps. An additional left-sided instrument port, which is primarily used for retraction, is placed at the posterior axillary line, just above the diaphragm.
Mediastinal Resections
Robotic mediastinal surgery can be approached from the left chest, right chest, or bilaterally. Each access strategy has its own particular advantages and disadvantages. Ultimately, the approach depends on the anatomy of the lesion, most commonly its predominant sidedness, or involvement of critical sided structures such as the phrenic nerve. A supine position, modified with the patient’s ipsilateral side bumped at an approximate 30° angle, is safe and effective for robotic mediastinal surgery ( Fig. 3 ). The ipsilateral arm is allowed to lay beneath the operating table on a slim arm board, exposing the operative chest. The contralateral arm is tucked to allow space for the robotic system, which is driven perpendicular to the patient from the opposite side.
