Anesthesia for laparoscopic and abdominal robotic surgery in adults

INTRODUCTION — The laparoscopic approach has become a standard of care for many abdominal surgical procedures. Compared with laparotomy, laparoscopy allows smaller incisions, reduces the perioperative stress response, reduces postoperative pain, and results in shorter recovery time. Abdominal robotic surgery is performed laparoscopically and is most commonly used for gynecologic and urologic surgery, although use is expanding in other specialties.

Anesthetic concerns for patients undergoing laparoscopic and robotic surgery differ from those for patients undergoing open abdominal surgery. Laparoscopy requires insufflation of intraperitoneal or extraperitoneal gas, usually carbon dioxide (CO₂), to create space for visualization and surgical maneuvers.

Physiologic effects of the pneumoperitoneum, absorption of CO₂, and positioning required for surgery can influence intraoperative care and outcomes. In addition, some laparoscopic/robotic procedures take longer than the open alternative.

This topic will discuss the anesthetic management of patients having laparoscopic and robotic abdominal surgery. Advantages and disadvantages of laparoscopy and robotic surgery, technical aspects of these techniques, and surgical complications are discussed separately. (See "Robot-assisted laparoscopy" and "Complications of laparoscopic surgery" and "Instruments and devices used in laparoscopic surgery" and "Laparoscopic cholecystectomy".)

SURGICAL TECHNIQUES — Laparoscopy requires creation of a pneumoperitoneum by insufflation of gas, usually carbon dioxide (CO₂), to open space in the abdomen for visualization and surgical manipulation. CO₂ insufflation can be performed blindly using a Veress needle or by placement of a port under direct vision through a small subumbilical incision. The gas source is connected to the needle or port; intraabdominal pressure (IAP) is monitored as gas is insufflated, aiming for a pressure ≤15 mmHg to minimize physiologic effects. For laparoscopic prostatectomy, which is performed in steep Trendelenburg position, the European Association for Endoscopic Surgery recommends IAP below 12 mmHg [1].

After insufflation, a port is placed, and the laparoscope is inserted. Under direct intraabdominal vision, further instrument ports are placed. The surgeon uses a video monitor connected to the laparoscope to see intraabdominal contents and perform the procedure.

In some cases, laparoscopy is used to assist dissection, after which an incision is made to complete the procedure. In others, a larger port is placed to allow the surgeon to insert one hand to assist the procedure.

The most commonly used robotic system occupies a lot of space in the operating room, and consists of a surgeon's control console, a tower holding the optical system, and patient-side cart with robotic arms (figure 1). For robotic surgery, once the pneumoperitoneum is created, multiple ports are placed for insertion of the camera and robotic arms, which are connected to the patient-side cart. The surgeon operates the camera and the robotic arms from the control console, remote from the patient, while an assistant is at the patient's side for suctioning, retraction, and passage of suture or sponges in and out of the abdomen.

PREOPERATIVE EVALUATION — A medical history and anesthesia-directed physical examination should be performed for all patients who undergo anesthesia. In anticipation of laparoscopy, we focus the preoperative evaluation on those medical conditions that may affect the response to physiologic changes associated with laparoscopy and the surgical procedure. The laparoscopic approach is used for surgical procedures with a range of risks of perioperative cardiac and pulmonary adverse events and surgical complications. As examples, diagnostic laparoscopy may be a brief procedure with minimal tissue trauma, while laparoscopic radical hysterectomy requires extensive dissection, may take a number of hours, and can result in significant blood loss.

We believe that preoperative evaluation for laparoscopic procedures should be the same as it would be for the equivalent open procedure. (See "Evaluation of perioperative pulmonary risk" and "Evaluation of cardiac risk prior to noncardiac surgery".)

PHYSIOLOGIC EFFECTS OF LAPAROSCOPY

Cardiovascular changes — The cardiovascular changes during laparoscopy are variable and dynamic (table 1) [2-5]. These effects are generally well tolerated by healthy patients. However, significant intraoperative cardiac dysfunction can occur in older patients and in those with cardiopulmonary disease (eg, chronic obstructive pulmonary disease [COPD], congestive heart failure, pulmonary hypertension, valvular heart disease). Studies of hemodynamic events during laparoscopy in patients with significant cardiopulmonary disease have reported an increase in mean arterial pressure (MAP), systemic vascular resistance (SVR), and central venous pressure (CVP), with decreases in cardiac output (CO) and stroke volume (SV) during peritoneal insufflation [6-10]. Compared with healthy patients, those with cardiopulmonary disease may require more pharmacologic interventions and more intensive monitoring to respond to these changes.

Cardiovascular changes during laparoscopy relate to the increase in intraabdominal pressure (IAP) associated with carbon dioxide (CO₂) insufflation, effects of positioning, and of absorption of CO₂, as follows:

●Effects of pneumoperitoneum – Pneumoperitoneum and the associated increase in IAP result in neuroendocrine and mechanical effects on cardiovascular physiology.

•Neuroendocrine effects – Increase in IAP results in catecholamine release and activation of the renin–angiotensin system with vasopressin release [11-13]. This increases MAP in most patients and may contribute to increases in SVR and pulmonary vascular resistance (PVR) [14].

Vagal stimulation, from insertion of the Veress needle or peritoneal stretch with gas insufflation, can result in bradyarrhythmias. Bradycardia is common in this setting, while atrioventricular dissociation, nodal rhythm, and asystole have been reported [15].

•Mechanical effects – Mechanical aspects of laparoscopy are dynamic; the resulting cardiovascular effects depend on the patient's preexisting volume status, insufflation pressure, and position. Compression of arterial vasculature with pneumoperitoneum increases SVR and PVR, with variable effects on CO and blood pressure (BP) [11-13].

Hypercarbia caused by CO₂ absorption may also increase SVR and PVR; in most cases, minute ventilation is increased to prevent hypercarbia, but the increase in intrathoracic pressure that accompanies ventilator adjustments may further increase SVR and PVR.

Cardiovascular effects tend to resolve quickly as pneumoperitoneum is maintained. A study of hemodynamic data in 38 patients who underwent laparoscopic cholecystectomy reported decreases in cardiac index, SV, and left ventricular (LV) end-diastolic volume after insufflation of CO₂ to 15 mmHg, with normalization of all values within 15 minutes [16].

●Effects of positioning – Laparoscopic surgery is often performed in head-up (eg, for cholecystectomy) or head-down (eg, pelvic surgery) positions to allow the intraabdominal organs to fall away from the surgical field. Extremes of position can affect cardiovascular function.

•Head up – The head-up position (ie, reverse Trendelenburg) leads to venous pooling, tends to reduce venous return to the heart [12,17], and may result in hypotension, especially in patients who are hypovolemic.

•Head down – The-head down position (ie, Trendelenburg) position increases venous return and cardiac filling pressures. A study of the hemodynamic effects of laparoscopy included 16 patients who underwent laparoscopic radical prostatectomy with 12 mmHg intraabdominal pressure and a 45 degree Trendelenburg position [5]. CVP, mean pulmonary artery pressure, and pulmonary capillary wedge pressure increased two- to threefold, and mean arterial BP (ABP) increased by 35 percent, without changes in CO, heart rate (HR), or SV. Cardiac filling pressures normalized immediately after surgery.

●Effects of hypercarbia – Absorption of CO₂ during laparoscopy can have direct and indirect cardiovascular effects. The direct effects of hypercarbia and associated acidosis include decreased cardiac contractility, sensitization to arrhythmias, and systemic vasodilation. Indirect effects are the result of sympathetic stimulation, and include tachycardia and vasoconstriction, which may counteract vasodilation [12]. (See 'Pulmonary changes' below.)

Pulmonary changes — Pneumoperitoneum with CO₂ and surgical positioning are associated with changes in pulmonary function and gas exchange (table 2). These changes can result from increased IAP with pneumoperitoneum and from absorption of CO₂.

During laparoscopy, minute ventilation must be increased to compensate for absorption of CO₂. Hyperventilation may be difficult for patients with COPD, asthma, and/or severe obesity, especially in Trendelenburg position. In patients with COPD and in older patients, end-tidal CO₂ (ETCO₂) may not accurately reflect arterial partial pressure of CO₂; in such patients, arterial blood gases may be required to monitor ventilation.

The absorption and elimination of CO₂ in patients with severe obesity appears to be similar to patients without obesity [18]. Arterial oxygenation decreases and alveolar–arterial oxygen gradient increases in anesthetized patients with obesity when placed in Trendelenburg position, though CO₂ insufflation tends to slightly reverse these effects [19].

●Changes in pulmonary mechanics – Pneumoperitoneum causes cephalad displacement of the diaphragm and mediastinal structures, which reduces functional residual capacity (FRC) and pulmonary compliance, resulting in atelectasis and increased peak airway pressures. These effects are exacerbated with steep Trendelenburg positioning (eg, during pelvic surgery) and are reduced with reverse Trendelenburg positioning (eg, during cholecystectomy and gastric surgery). The changes in pulmonary compliance may be less with retroperitoneal insufflation (eg, during renal or adrenal procedures) compared with intraperitoneal insufflation [20].

●CO₂ absorption – CO₂ is highly soluble and is rapidly absorbed into the circulation during insufflation for laparoscopy. CO₂ absorption increases quickly and reaches a plateau at approximately 60 minutes of insufflation [20-22]. Ventilation must be increased to maintain normal end-tidal and arterial partial pressure of CO₂ (figure 2). (See 'Mechanical ventilation' below.)

Surgical technique may influence the degree of CO₂ absorption. Multiple studies have found that subcutaneous emphysema, a possible complication of laparoscopy, is associated with increased absorption of CO₂ [21-23]. (See 'Subcutaneous emphysema' below.)

Subcutaneous emphysema may be more common during retroperitoneal insufflation of CO₂ compared with intraperitoneal insufflation, but it is not clear whether the retroperitoneal approach itself increases CO₂ absorption. Findings from studies that compared CO₂ absorption with these two techniques without subcutaneous emphysema have reported conflicting results [21-24].

●Ventilation/perfusion matching – The reduction in FRC and atelectasis associated with laparoscopy may theoretically lead to shunting and ventilation/perfusion mismatch; however, in healthy patients, these effects are minimal and well tolerated, even with steep Trendelenburg positioning [4,5,25].

●Endotracheal tube position – Pneumoperitoneum and Trendelenburg positioning may cause cephalad movement of the carina, which can result in mainstem endobronchial migration of the endotracheal tube, hypoxia, and high inspiratory pressure [26,27]. In addition, endotracheal tube cuff pressure increases in some patients during laparoscopy [28].

Regional circulatory changes

●Splanchnic blood flow – The mechanical and neuroendocrine effects of pneumoperitoneum can decrease splanchnic circulation, resulting in reduced total hepatic blood flow and bowel perfusion. However, hypercapnia can cause direct splanchnic vasodilatation. Thus, the overall effects on splanchnic circulation are not clinically significant [29,30].

●Renal blood flow – The creation of a pneumoperitoneum results in reduction in renal perfusion and urine output associated with renal parenchymal compression, reduced renal vein flow, and increased levels of vasopressin [31-33]. When IAP is kept under 15 mmHg, renal function and urine output generally normalize soon after pneumoperitoneum deflation, without histologic evidence of pathologic changes.

The effects of laparoscopy on renal function for patients with preexisting renal disease have not been studied. In most cases, we believe that the benefits of a minimally invasive surgical approach outweigh theoretical concerns about the effect of increased intraabdominal pressure on renal function.

●Cerebral blood flow – Increased intraabdominal and intrathoracic pressures, hypercarbia, and Trendelenburg positioning can all increase cerebral blood flow (CBF) and intracranial pressures (ICP) [34]. In healthy patients undergoing prolonged pneumoperitoneum and steep Trendelenburg position, cerebral oxygenation and cerebral perfusion remain within safe limits [35]. In a small study of patients undergoing laparoscopic cholecystectomy, internal carotid blood flow reduced significantly after induction of anesthesia, positive pressure ventilation, and pneumoperitoneum [36]. The reduction in internal carotid artery blood flow was independently associated with reduced CO, despite unchanged MAP, depth of anesthesia, and end-tidal carbon dioxide levels. However, clinical significance of these findings in relatively healthy patients remains unclear. In patients with intracranial mass lesions or significant cerebrovascular disorders (eg, carotid atherosclerosis and cerebral aneurysm), the increase in ICP may have clinical consequences. Therefore, in this patient population, we maintain strict normocapnia during laparoscopy.

●Intraocular pressure – Intraocular pressure (IOP) increases with pneumoperitoneum and increases further when the patient is positioned in Trendelenburg [37-39]. A prospective observational study of IOP in patients who underwent robotic laparoscopic prostatectomy and hysterectomy in steep Trendelenburg position found that IOP increased and lasted until 45 to 60 minutes after surgery [40]. The clinical implications of this degree of increase are unknown, though increased IOP may play a role in the rarely reported postoperative visual loss in patients with prolonged cases. (See 'Complications related to positioning' below and "Postoperative visual loss after anesthesia for nonocular surgery", section on 'Postoperative ischemic optic neuropathy'.)

ANESTHETIC MANAGEMENT

Choice of anesthetic — In most cases, we perform general anesthesia for laparoscopy and robotic surgery. For procedures performed in Trendelenburg position, general anesthesia with endotracheal intubation allows optimal ventilatory control and support [41].

Others use spinal or epidural anesthesia for short procedures in the supine or head-up position (eg, diagnostic laparoscopy, laparoscopic cholecystectomy) [42-44]. A sensory level of T4 to T6 is required for adequate neuraxial anesthesia.

Monitoring and intravenous access — As for any anesthetic, standard American Society of Anesthesiologists (ASA) monitors (eg, blood pressure [BP], electrocardiography, oxygen saturation, capnography, and temperature) are applied prior to laparoscopy. Further monitoring (eg, continuous intraarterial pressure) should be added as required by the patient's medical condition, the expected blood loss, and the duration of surgery. (See "Basic patient monitoring during anesthesia".)

All patients require placement of at least one venous catheter for anesthesia. The need for additional or high-capacity venous access should be dictated by the expected blood loss.

Many robotic procedures and some laparoscopic procedures are performed with the patient's arms tucked at the sides, limiting access for blood sampling, placement of an arterial catheter, or additional venous access during the procedure.

Induction of anesthesia — A variety of medications and techniques can be used for induction of anesthesia and are chosen based on patient factors. For most adults, intravenous (IV) induction is performed. (See "Induction of general anesthesia: Overview".)

After induction, the eyes should be closed and covered (ie, with tape or adhesive transparent dressing) to avoid corneal damage. An orogastric tube should be placed and suctioned to decompress the stomach prior to needle or trocar insertion and to minimize stomach injury.

Choice of airway device — We place an endotracheal tube for airway management for laparoscopy, rather than a supraglottic airway (SGA), to provide optimal control of ventilation for elimination of carbon dioxide (CO₂) and to protect against aspiration. A cuffed endotracheal tube allows the use of positive end expiratory pressure (PEEP) and the high peak airway pressures that may be required during pneumoperitoneum, especially with Trendelenburg positioning.

SGAs are commonly used for airway management for anesthesia and can be used with positive pressure ventilation. The use of SGAs for laparoscopy is controversial. These devices do not fully protect against aspiration of stomach contents and are ordinarily used with lower peak inspiratory pressures. However, there are a number of studies and case reports describing the safe use of second-generation SGAs for laparoscopic procedures [45-48]. Second-generation SGAs allow the use of higher airway pressure without leak and have esophageal vents to minimize the chance of aspiration. (See "Supraglottic devices (including laryngeal mask airways) for airway management for anesthesia in adults", section on 'Choice of supraglottic airway'.)

Positioning — Laparoscopy is often performed in extreme head-up (ie, reverse Trendelenburg) (eg, for cholecystectomy or gastric surgery) or head-down (ie, Trendelenburg) (eg, pelvic surgery) positions to allow the intraabdominal organs to fall away from the surgical field. In addition, any of the positions used for open procedures may be required (ie, lithotomy, lateral decubitus, operating room [OR] table flexion or rotation). The arms are often tucked at the patient's sides for laparoscopic and robotic surgery. As for all longer surgical procedures, a goal for positioning and padding is the prevention of injuries to peripheral nerves and bony prominences. Pressure points should be padded, as should the plastic connectors on IV tubing and monitoring devices. (See 'Complications related to positioning' below.)

Positioning devices are often used to avoid having the patient slide on the operating table with steep Trendelenburg or reverse Trendelenburg positioning. A foot support attached to the end of the operating table may be used for laparoscopic cholecystectomy and other procedures that require reverse Trendelenburg positioning.

Nonslip padding and cross-body taping are options for preventing the patient from sliding on the operating table during steep Trendelenburg positioning. We use nonslip padding with cross-body taping (ie, tape attached to the operating table from over the shoulder to near the opposite hip). Shoulder supports have been associated with brachial plexus injury; if they are used, they should be placed laterally, at the acromioclavicular joint, to avoid direct nerve compression (see "Patient positioning for surgery and anesthesia in adults", section on 'Nerve injuries associated with the Trendelenburg position'). We test for sliding with maximal Trendelenburg positioning prior to surgical prep and drape and confirm that taping does not restrict chest excursion or affect ventilation.

For robotic surgery, once the robotic device is docked with the arms connected to the instruments, the position of the operating table must not be changed. With instruments in fixed position, patient movement can result in injury to the abdominal wall and intraabdominal structures.

Maintenance of anesthesia

Use of nitrous oxide — As for open abdominal procedures, various inhalation and IV anesthetics can be used for maintenance of general anesthesia for laparoscopy [41]. (See "Maintenance of general anesthesia: Overview".)

The use of nitrous oxide (N₂O) for maintenance during laparoscopy is controversial. In our view, the balance of the literature on the use of N₂O along with prophylaxis for postoperative nausea and vomiting (PONV) for laparoscopy supports its use when clinically indicated. For longer procedures, if the surgeon reports difficulty with exposure related to bowel distention, N₂O may be discontinued.

Concerns regarding the use of N₂O for laparoscopy include an increase in PONV and bowel distention.

●PONV – Although N₂O is associated with a modestly higher incidence of PONV than other inhalation anesthetic agents, this can be mitigated by antiemetic prophylactic measures [49,50]. (See "Postoperative nausea and vomiting", section on 'Anesthetic factors'.)

●Bowel distention – N₂O diffuses into air-containing closed spaces over time and can lead to bowel distention, which can theoretically impair surgical exposure and dissection. Based on small studies, N₂O does not appear to affect operating conditions during relatively short procedures [41]. A surgeon-blinded study of operating conditions during laparoscopic cholecystectomy lasting an average of 75 minutes with and without N₂O found no difference in technical difficulty with N₂O administration [51]. Similarly, a surgeon-blinded study of the effects of N₂O during 50 laparoscopic gastric bypass surgeries found no noticeable bowel distention during 90 minutes of anesthesia [52]. In both of these studies, the surgeons correctly determined that N₂O was being used less than half of the time.

Bowel distention with laparoscopy may be a more significant concern during longer procedures since diffusion of N₂O into gas-filled spaces increases over time. In a surgeon-blinded study of approximately 350 patients who underwent colon surgery lasting 3 to 3.5 hours, surgeons were asked to rate intraoperative bowel distention at the end of surgery [53]. Moderate or severe bowel distention occurred more than twice as often when N₂O was administered compared with air (23 percent versus 9 percent), but there was no reported bowel distention in the majority of cases in both groups.

Neuromuscular blockade — Neuromuscular blocking agents (NMBAs) are administered during abdominal surgery to facilitate endotracheal intubation and to improve surgical conditions. The literature regarding the need for and optimal level of neuromuscular blockade during laparoscopic procedures is inconclusive. Some studies have shown improved surgical exposure in this setting with deep block (ie, train-of-four twitch count of zero but post-tetanic count of 1 to 2) compared with moderate block (ie, train-of-four twitch count of ≥1) [54-58], while others have shown no benefit from deeper block [59,60]. A 2018 meta-analysis of randomized controlled trials that compared deep with moderate neuromuscular blockade during laparoscopy found insufficient evidence to support the use of deep neuromuscular blockade [61]. A 2019 randomized trial of 35 patients who underwent laparoscopic robotic surgery in the Trendelenburg position found that respiratory mechanics, regional aeration and ventilation, and hemodynamics were similar in patients who received deep versus moderate neuromuscular blockade [62].

We administer NMBAs as required by the clinical situation, aiming for the least degree of block necessary for the clinical situation. The need for neuromuscular blockade may depend on the surgical procedure, positioning, and the patient's body habitus. As examples, exposure during laparoscopic cholecystectomy in a lean patient may be adequate with minimal neuromuscular block, while laparoscopic deep-pelvic surgery may require relatively deep block to optimize surgical conditions.

During robotic procedures, deep neuromuscular block should be maintained as long as the robotic device is docked with intraabdominal instruments attached. In this setting, any degree of unexpected patient movement can result in injury.

Mechanical ventilation — The dynamic changes in pulmonary function during laparoscopy require intraoperative adjustment of mechanical ventilation (algorithm 1). (See 'Pulmonary changes' above.)

Our strategy for ventilation — We follow a lung-protective intraoperative ventilatory strategy using pressure-controlled ventilation with volume guarantee. If this mode of ventilation is unavailable, we use volume-controlled ventilation. We start with a fraction of inspired oxygen (FiO₂) of 0.5, tidal volume of 6 to 8 mL/kg ideal body weight, and with PEEP of 5 to 10 cm H₂O, at a respiratory rate of 8 breaths/minute. We adjust these settings to maintain ETCO₂ at approximately 40 mmHg and oxygen saturation (SaO₂) >90 percent. Such a strategy may improve oxygenation during laparoscopy [63-67]. Most, though not all studies have reported a lower incidence of postoperative pulmonary complications with intraoperative lung protective ventilation. This is discussed separately. (See "Mechanical ventilation during anesthesia in adults", section on 'Components of intraoperative lung protective ventilation'.)

For patients who develop the following conditions, we modify ventilation as follows:

●For peak pressures over 50 cm H₂O, we set the I:E ratio at 1:1.

●For hypoxia (ie, SaO₂ <90 percent), we auscultate breath sounds bilaterally to rule out endobronchial intubation and bronchospasm. We increase the FiO₂ and perform a recruitment maneuver (maintain peak airway pressures at 30 cm H₂O for 20 to 30 seconds if arterial BPs [ABPs] permit); if oxygenation improves, we increase PEEP values and perform periodic recruitment maneuvers (eg, every 30 minutes). (See 'Pulmonary complications' below.)

●If hypoxemia and/or high peak airway pressures persist for patients in Trendelenburg position, we reduce the degree of tilt and/or reduce the insufflation pressure (eg, from 15 to 12 mmHg or less).

●We prefer to increase the respiratory rate, rather than the tidal volume, to increase minute ventilation and compensate for CO₂ absorption. We accept mild hypercapnia (ie, end-tidal CO₂ [ETCO₂] approximately 40 mmHg) if necessary to maintain peak airway pressures under 50 cm H₂O in order to avoid barotrauma. In addition, mild hypercarbia can improve tissue oxygenation by increasing cardiac output (CO) and vasodilation, and a shift to the right of the oxyhemoglobin dissociation curve [41,68,69].

For hypercarbia (ie, ETCO₂ >50 mmHg) despite hyperventilation, we examine for signs of subcutaneous emphysema. (See 'Subcutaneous emphysema' below.)

●If hypercarbia and/or hypoxia persist, we discuss further reduction in insufflation pressure or conversion to open surgery.

Modes of ventilation — Various modes of ventilation have been used in an attempt to reduce peak inspiratory pressure during laparoscopy.

●While pressure support ventilation may reduce the chance of high inspiratory pressure compared with volume control, changes in intraabdominal pressure (IAP) during surgery can result in varied minute ventilation with pressure control settings. Pressure control with volume guarantee, where available, can be used to limit peak airway pressure while maintaining constant ventilation [70]. (See "Mechanical ventilation during anesthesia in adults", section on 'Pressure control with volume guarantee'.)

●During laparoscopic robotic surgery the driving pressures are distributed more to the chest wall and less to the lungs [62]. Therefore, it may be necessary to accept higher peak airway and driving pressures to prevent lung collapse and maintain adequate ventilation.

●Alveolar recruitment in conjunction with high PEEP (15 cm H₂O) applied before the onset of pneumoperitoneum may prevent the alveolar collapse induced by pneumoperitoneum, though this approach has not been shown to improve postoperative lung function [71]. Higher PEEP levels may be more appropriate in high risk patients in whom impaired pulmonary mechanics is more likely to cause injury [72].

●Increasing the inspiratory to expiratory (I:E) ratio may be beneficial in steep Trendelenburg position during laparoscopy. A study of ventilatory strategy in 80 patients who underwent robotic laparoscopy found that an I:E ratio of 1:1 reduced peak inspiratory pressure compared with a ratio of 1:2 without a change in CO, though there was no difference in oxygenation [73].

●One study found that the respiratory effects of increased intraabdominal pressures may be counterbalanced with targeted PEEP; however, a preferable approach may be to lower abdominal pressures [74].

●In some patients with obesity complete airway closure (ie, lack of communication between proximal airways and alveoli due to airway collapse), can occur with induction of anesthesia, and alveolar opening pressure may increase to very high levels with institution of pneumoperitoneum and Trendelenburg positioning [75]. This suggests that pressure-controlled modes may not be appropriate for many patients with obesity, as the increased airway opening pressures may prevent ventilation unless very high peak pressures are used.

Fluid management — Perioperative fluid therapy is one of the major factors known to influence postoperative outcomes after abdominal surgery. Avoidance of fluid excess improves outcome after major gastrointestinal surgery by reducing bowel edema and interstitial fluid accumulation. Intraoperative fluid therapy is discussed in greater depth separately (see "Intraoperative fluid management"). We administer balanced crystalloid solution 3 to 5 mL/kg/h as baseline supplemented with additional fluids based on blood loss.

In patients undergoing robotic surgery in prolonged steep head-down position, excessive fluid administration may result in facial, pharyngeal, and laryngeal edema. Traditional indicators used to guide fluid therapy (eg, heart rate [HR], ABP, central venous pressures [CVPs], and urine output) are unreliable. Dynamic indicators such as stroke volume (SV) or systolic pressure variation may also be unreliable, and use of invasive or noninvasive monitors for goal-directed therapy in laparoscopic procedures remains controversial. The cardiopulmonary changes resulting from intraabdominal CO₂ insufflation interfere with interpretation of the dynamic variables (eg, SV variation, pulse pressure variation, systolic pressure variation). We use these monitors or place arterial lines selectively in patients with significant cardiopulmonary disease. (See "Intraoperative fluid management", section on 'Dynamic parameters to assess volume responsiveness'.)

Nausea and vomiting prophylaxis — Laparoscopy has been identified as a risk factor for PONV, though the literature on this issue is conflicting [76]. Although risk-based approaches for antiemetic therapy have been proposed, the compliance with these strategies is poor [77]. Therefore, routine prophylactic multimodal antiemetic therapy should be utilized in all patients undergoing laparoscopic/robotic surgery. The number of antiemetic medications can be based on the patient's level of risk [77]. Our approach to antiemetic prophylaxis in this setting is as follows:

●All patients – We administer dexamethasone (4 to 8 mg IV after induction) and 5-HT₃ antagonists (eg, ondansetron 4 mg at the end of surgical procedure).

●High-risk patients – For patients at very high risk of PONV (eg, female patients, history of motion sickness, history of previous PONV, high opioid requirements for pain relief), we administer additional antiemetic therapy with preoperative transdermal scopolamine (1.5 mg transdermal patch). In addition, we use total IV anesthesia (TIVA) with propofol.

●Rescue therapy – For rescue therapy in the immediate postoperative period, we administer low-dose promethazine (6.25 mg IV, slowly) or dimenhydrinate (1 mg/kg IV). Extravasation of promethazine can cause tissue damage, thus the IV should be tested for patency and the site visible during administration. Promethazine should be diluted with saline to a concentration ≤1 mg/mL to avoid irritation of the vein.

The management of PONV is discussed in more detail separately. (See "Postoperative nausea and vomiting".)

Postoperative pain management — The origins of pain after laparoscopic and robotic surgical procedures may be both somatic (ie, from port-site incisions) and visceral (ie, from peritoneal stretch and manipulation of abdominal tissues). The degree of pain after laparoscopic and robotic surgery is usually low to moderate [78,79] and is less than the corresponding open procedure, but the degree of pain depends on the specific surgery. (See "Approach to the management of acute pain in adults".)

We follow a procedure-specific, multimodal approach to the management of postoperative pain, starting prior to and continuing in the OR [78-81]. We aim to minimize perioperative administration of opioids [82]. Pain after laparoscopy can often be managed effectively with acetaminophen, nonsteroidal antiinflammatory drugs (NSAIDs) or cyclooxygenase₂ (COX₂)-specific inhibitors, and dexamethasone [81,83-87]. We routinely infiltrate the incisions with local anesthetic (LA) at the time of wound closure [88]. In the postoperative period, if necessary, low- to moderate-intensity pain may be treated with weak opioids (eg, tramadol), and moderate- to high-intensity pain may be treated with strong opioids (eg, hydrocodone and oxycodone) [81].

For hybrid or laparoscopy-assisted surgical procedures with longer incisions, fascial plane blocks (eg, transversus abdominis plane blocks) may be beneficial [89] (see "Transversus abdominis plane (TAP) blocks procedure guide"). Alternatively, surgical site infiltration has also been shown to provide good pain relief [88].

The author does not use neuraxial analgesia (ie, continuous epidural analgesia or intrathecal opioids) for postoperative pain after laparoscopic surgery, while others may use these techniques in selected patients [81].

Neuraxial analgesia is usually unnecessary and not beneficial. Epidural analgesia may delay ambulation and increase the length of stay [81,90]. A review of registry data from an enhanced recovery after surgery (ERAS) protocol for colon surgery found that while the laparoscopic approach reduced the hospital length of stay (odds ratio [OR] 0.83), the addition of epidural analgesia to laparoscopy modestly increased the length of stay (OR 1.1) [91]. Similarly, a database review of approximately 192,000 laparoscopic colorectal procedures reported an increase in mean length of stay in patients who had epidural analgesia (six days versus five days, mean difference 0.6 days, 95% CI 0.27-0.93 days) [92].

Intraperitoneal instillation of LAs (eg, bupivacaine and ropivacaine) may reduce the intensity of postlaparoscopic pain [93], but the concentration and dose of the LA, as well as optimal timing of administration, remain unknown, and routine use has not been recommended [78,80]. Management of postoperative pain is discussed in more depth separately. (See "Approach to the management of acute pain in adults".)

INTRAOPERATIVE COMPLICATIONS — Complications during laparoscopy include those related to the physiologic effects of the laparoscopic approach (eg, hemodynamic compromise, respiratory decompensation), surgical maneuvers (eg, access-related injury; vascular, solid-organ, or bowel injury; carbon dioxide [CO₂] spread to subcutaneous and intrathoracic spaces; gas embolism), and patient positioning [79,94-99]. The impact of intraoperative complications on the anesthetic management of patients is discussed in the following sections. Further details regarding the complications of laparoscopic surgery are discussed separately. (See "Complications of laparoscopic surgery".)

Hemodynamic complications — Hypotension, hypertension, and arrhythmias can occur during laparoscopy as a result of the physiologic effects of the technique (table 3). (See 'Cardiovascular changes' above.)

●During insufflation – Surgical injury during abdominal access (eg, gas embolism, vascular or solid organ injury with hemorrhage) can cause rapid cardiovascular decompensation. Initial abdominal insufflation is a time for hypervigilance with regard to blood pressure (BP), heart rate (HR), peak inspiratory pressures, end tidal CO₂ (ETCO₂), and oxygen saturation. Changes in vital signs should be immediately discussed with the surgeon to allow reevaluation of the position of the needle or port and possible release of the pneumoperitoneum.

Treatment of hemodynamic dysfunction includes confirmation that intraabdominal pressure (IAP) is within acceptable limits; exclusion of treatable causes; and supportive therapy including reduction in anesthetics, fluid administration, and pharmacologic interventions. If supportive therapy is ineffective, deflation of the abdomen may be necessary. After cardiopulmonary stabilization, cautious, slow re-insufflation may then be attempted using lower IAP. However, with persistent signs of significant cardiopulmonary impairment, it may be necessary to convert to an open procedure.

●During surgery – During surgery, hemodynamic instability can occur for a variety of reasons and may be more likely in patients with cardiac comorbidities. (See 'Cardiovascular changes' above.)

•Hemorrhage – Hemorrhage may be less obvious during laparoscopic procedures because of the limited and focused surgical field. Unexplained hypotension should be discussed with the surgeon.

•Hyperventilation – When ventilation is increased to compensate for CO₂ absorption, venous return to the heart may be compromised and result in hypotension, especially with the use of positive end-expiratory pressure (PEEP). Fluid administration and/or change in ventilatory settings may improve BP. (See 'Mechanical ventilation' above.)

•Positioning – Head-up positioning can cause venous pooling and reduced venous return to the heart. Vasopressor administration (eg, phenylephrine) and/or fluid administration may be required.

Pulmonary complications — Pulmonary complications during laparoscopy, including hypercarbia and hypoxemia, can relate to the physiologic effects of the technique (eg, altered respiratory mechanics, CO₂ absorption, ventilation perfusion mismatch) or surgical injury (eg, diaphragm or lung injury) (table 4 and table 5).

●Hypercarbia – It may be necessary to increase ventilation during laparoscopy to compensate for CO₂ absorption. When hypercarbia or an increase in ETCO₂ occurs despite increase in ventilation, causes for increased absorption or decreased elimination of CO₂ should be considered, including both those that may occur during any anesthetic and those specific to laparoscopy (table 4).

When severe hypercarbia occurs during laparoscopy, the patient should be examined for signs of subcutaneous emphysema (ie, crepitus over the abdomen, chest, clavicles and neck). (See 'Subcutaneous emphysema' below.)

When high ETCO₂ persists despite aggressive hyperventilation (eg, peak airway pressures >50 cm H₂O), reduced insufflation pressure or conversion to open surgery may be required.

●Hypoxia – Oxygen desaturation can occur during laparoscopy as a result of the physiologic changes of the technique, surgical positioning, or for reasons that hypoxia can occur during any anesthetic (table 5).

The chest should be auscultated for the quality and presence of bilateral breath sounds to rule out bronchospasm and endobronchial intubation. Initial treatment includes an increase in inspired oxygen concentration. Unless the patient is hypotensive, a recruitment maneuver should be performed (ie, manual breath with plateau pressure 30 cm H₂O, held for 20 to 30 seconds duration, if BP permits), and PEEP should be optimized. If refractory hypoxemia occurs, the pneumoperitoneum should be released.

Carbon dioxide insufflation

Subcutaneous emphysema — Subcutaneous emphysema can occur during laparoscopy when CO₂ is insufflated into subcutaneous tissues. This can occur during intraperitoneal insufflation with an improperly placed Veress needle or trocar, during extraperitoneal laparoscopy (eg, renal surgery), or during upper abdominal laparoscopy (eg, Nissen fundoplication) [23,100]. In rare cases, gas can track into the thorax and mediastinum, thereby resulting in capnothorax, capnomediastinum, and capnopericardium (table 6) [101]. (See 'Capnothorax' below.)

The following have been identified as risk factors for subcutaneous emphysema during laparoscopy [102]:

●Surgery lasting longer than 200 minutes

●The use of six or more surgical ports

●Patient age >65

●Nissen fundoplication surgery

Multiple studies have found that subcutaneous emphysema is associated with increased absorption of CO₂ [21-23]. When hypercarbia occurs despite hyperventilation, the patient should be examined for signs of subcutaneous gas over the abdomen, chest, and neck. If crepitus or swelling is found, the surgeon should be notified; readjustment of ports, reduction of insufflation pressure, or conversion to open surgery may be required.

In most cases, subcutaneous emphysema resolves after the abdomen is deflated, and no specific intervention is required. When crepitus or swelling occurs in the head, neck, or upper chest, the potential for airway compromise after extubation is increased, especially for patients who may be edematous after prolonged procedures in Trendelenburg position. In most cases, subcutaneous CO₂ is superficial and does not compromise the airway lumen. When external swelling is severe, options include the following:

●Laryngoscopy to assess airway edema while the patient is anesthetized.

●Extubation over a tube changer. (See "Management of the difficult airway for general anesthesia in adults", section on 'Extubation'.)

●Delayed extubation for several hours, with the patient positioned head-up, to allow resorption of CO₂.

Absorption of CO₂ from subcutaneous emphysema may continue for up to several hours after surgery [103]. Healthy patients are able to increase ventilation to eliminate CO₂, but those with chronic lung disease or with opioid-induced respiratory depression can remain hypercarbic and acidotic early in the postoperative period. Somnolence, hypertension, and tachycardia may occur.

For symptomatic patients with subcutaneous emphysema of the head and neck region, a postoperative chest radiograph should be performed to rule out capnothorax. Patients with significant subcutaneous emphysema should be observed in the post-anesthesia care unit (PACU) for several hours, until swelling begins to subside and vital signs are normal.

Capnothorax — Capnothorax, although rare, can be potentially life-threatening [95,104]. Causes of capnothorax are presented in a table (table 6). Capnothorax should be suspected in the setting of an unexplained increase in airway pressure, hypoxemia, and hypercapnia, especially during Nissen fundoplication. Other signs suggestive of capnothorax include subcutaneous emphysema of the head and neck, inequality in chest expansion, reduced air entry, and a bulging diaphragm (visualized by directing the videoscope towards the diaphragm) [105]. If necessary, a chest radiograph or transthoracic ultrasound can confirm the diagnosis of capno- or pneumothorax [106].

In this setting, treatment depends on the patient's hemodynamic and respiratory status and the stage of the surgery. If stable, reduction of insufflation pressure, hyperventilation, and increase in PEEP may be sufficient; CO₂ is resorbed quickly after even large capnothorax. In one reported case of near total capnothorax during Nissen fundoplication, the gas resorbed within one hour postoperatively, with no specific treatment [105].

However, hemodynamic compromise can occur, requiring placement of an intrathoracic needle or a chest tube for decompression and to allow completion of surgery [107-110]. If tension capnothorax persists despite these measures, conversion to open surgery may be required.

Capnomediastinum and capnopericardium — Capnomediastinum and capnopericardium, although rare, can be associated with significant hemodynamic compromise. Risk factors for these complications are similar to the risk factors for capnothorax. The diagnosis is made by chest radiograph (ie, air is visible in the mediastinum or pericardium). Management depends on the degree of hemodynamic compromise. In most patients, deflation of the pneumoperitoneum and close observation is adequate, while others might require supportive therapy along with hyperventilation.

Gas embolism — Venous gas embolism is extremely common during laparoscopy, though clinically significant emboli are rare. Studies using transesophageal echocardiography (TEE) during laparoscopic surgery have reported an incidence of subclinical gas embolism between 17 and 100 percent [111-114].

In this setting, gas embolism can occur via two mechanisms. Rarely, direct venous injection of CO₂ with the Veress needle can result in rapid, high-volume CO₂ embolism at the time of abdominal insufflation. Alternatively, CO₂ entrainment is possible if a vein is severed or disrupted during surgery, allowing the gas under pressure access to the circulation.

Signs of gas embolism include unexplained hypotension, abrupt reduction of ETCO₂, hypoxemia, and arrhythmias. The electrocardiogram (ECG) may show right heart strain with a widened QRS complex. Paradoxical embolism through a patent foramen ovale (PFO) or atrial septal defect (ASD) can occur, with cerebral or coronary ischemia.

If gas embolism is suspected, the abdomen should be deflated to reduce CO₂ entrainment, and ventilation should be increased to reduce the size of CO₂ bubbles, though hyperventilation may worsen hypotension. Since gas embolism results from a vascular injury, hemorrhage is possible when the intraabdominal pressure is reduced. Therefore, re-insufflation or open surgery may be required to stop hemorrhage if hemodynamic instability persists.

Treatment is otherwise supportive, with fluid and vasopressor administration and, if necessary, cardiopulmonary resuscitation. The left-lateral, head-down position may allow the gas bubble to float to the apex of the right heart, away from the pulmonary artery.

Complications from surgical instrumentation — Complications of surgical instrumentation can occur during abdominal access or during the surgical procedure. The complications of most concern to the anesthesiologist include vascular and abdominal organ injury, both of which can result in significant hemorrhage.

Up to half of serious surgical complications occur during placement of the Veress needle or an access port [115]. Therefore, significant injury and major hemorrhage can occur even during relatively low-risk procedures (eg, diagnostic laparoscopy, laparoscopic appendectomy). In this setting, surgical access to a bleeding vessel or organ may take time; BP should be supported with IV fluid and vasopressor administration, as necessary.

As with open surgical procedures, injury to intraabdominal structures can occur during dissection. Bleeding may be less obvious during laparoscopy than it is during open procedures. The view of the surgical field is limited, and blood can pool away from the surgical field when patients are in head-up or head-down position. Signs of hypovolemia (ie, hypotension, tachycardia) may suggest occult bleeding and should be brought to the surgeon's attention.

The incidence, risk factors, and technical aspects of surgical complications are discussed in more detail separately. (See "Complications of laparoscopic surgery".)

Complications related to positioning — Prolonged steep Trendelenburg positioning can cause conjunctival, nasal, and laryngopharyngeal edema and may result in increased upper airway resistance [26] and, rarely, postextubation laryngospasm and airway obstruction.

Both minor (ie, corneal abrasion) and significant (ie, ischemic optic neuropathy) ocular injuries have been reported after laparoscopy performed in steep Trendelenburg position. Postoperative visual loss and ocular injury are discussed in more detail separately. (See "Postoperative visual loss after anesthesia for nonocular surgery".)

As for other long surgical procedures, patients who undergo prolonged laparoscopy are at risk for position-related nerve injury and even compartment syndrome [116,117]. Pressure points, plastic tubing connectors, monitoring cables, and leg supports for lithotomy positioning should all be padded. With steep Trendelenburg positioning, the arms should be positioned without caudad pull on the shoulders to reduce the chance of brachial plexus stretch injury.

Shoulder braces may be used to prevent sliding during Trendelenburg positioning; their use has been associated with brachial plexus injury in this setting, though the incidence is unknown [118].

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Enhanced recovery after surgery".)

SUMMARY AND RECOMMENDATIONS

●Use of laparoscopic and robotic approaches – The laparoscopic approach has become the standard of care for many surgical procedures. Abdominal robotic surgery is performed laparoscopically; anesthetic concerns for conventional laparoscopy and robotic surgery are similar. (See 'Surgical techniques' above.)

●Physiologic effects

•Laparoscopy requires insufflation of CO₂ to create space for visualization and surgical maneuvers. The associated increase in intraabdominal pressure (IAP), along with absorption of CO₂ and effects of surgical positioning, result in neuroendocrine and mechanical changes that affect cardiopulmonary function. (See 'Physiologic effects of laparoscopy' above.)

•Cardiopulmonary physiologic changes include the following:

-Cardiovascular changes – Increased systemic vascular resistance (SVR), arterial blood pressure (ABP), and cardiac filling pressures (table 1). (See 'Cardiovascular changes' above.)

-Pulmonary changes – Increased intrathoracic pressure, reduced functional residual capacity (FRC), and increased airway pressures (table 2). (See 'Pulmonary changes' above.)

●Choice of anesthetic technique – We perform general anesthesia with endotracheal intubation for laparoscopy, though others have used regional anesthesia safely for short laparoscopic procedures. (See 'Choice of anesthetic' above.)

●Anesthetic agents

•When indicated, we administer nitrous oxide (N₂O) as part of a balanced general anesthetic, along with prophylaxis for postoperative nausea and vomiting (PONV). (See 'Use of nitrous oxide' above.)

•For laparoscopy, we administer neuromuscular blocking agents (NMBAs) based on clinical need, aiming for the least degree of block necessary for the clinical situation. For robotic surgery, we maintain deep neuromuscular blockade (ie, one twitch with train-of-four peripheral nerve stimulator) until the robotic device is undocked. (See 'Neuromuscular blockade' above.)

●Ventilation – We ventilate with a fraction of inspired oxygen (FiO₂) of 0.5, a starting tidal volume of 6 to 8 mL/kg ideal body weight, with positive end expiratory pressure (PEEP) of 5 to 10 cm H₂O, at a respiratory rate of 8 breaths/minute, adjusted to maintain end tidal CO₂ (ETCO₂) at approximately 40 mmHg and oxygen saturation (SaO₂) >90 percent. We use pressure control ventilation with volume guarantee; if unavailable, we use volume control ventilation. We modify ventilation during laparoscopy as follows:

•For peak pressures over 50 mmHg, we set the I:E ratio at 1:1. (See 'Mechanical ventilation' above.)

•For hypoxia (ie, SaO₂ <90 percent), we increase the FiO₂, auscultate bilaterally for breath sounds, and perform a recruitment maneuver (maintain peak airway pressures at 30 cm H₂O for 20 to 30 seconds if ABPs permit); if oxygenation improves, we increase PEEP values and perform periodic recruitment maneuvers (eg, every 30 minutes). (See 'Pulmonary complications' above.)

•If hypoxemia and/or high peak airway pressures persist, for patients in Trendelenburg position, we reduce the degree of tilt and/or reduce the insufflation pressure (eg, from 15 to 12 mmHg).

•For hypercarbia (ie, ETCO₂ >50 mmHg) despite hyperventilation, we examine for signs of subcutaneous emphysema. (See 'Subcutaneous emphysema' above.)

•If hypercarbia and/or hypoxia persist, we discuss reduction in insufflation pressure and/or degree of head down position or conversion to open surgery.

●Postoperative analgesia – Laparoscopic surgery results in less pain than the corresponding open procedure. We use a multimodal approach to postoperative pain control, including acetaminophen, nonsteroidal antiinflammatory drugs, and local/regional analgesia, with the addition of opioid medication only as necessary. (See 'Postoperative pain management' above.)

●Prophylaxis for postoperative PONV – We suggest prophylaxis for PONV for all patients who undergo laparoscopy (Grade 2C). We use the following approach (see 'Nausea and vomiting prophylaxis' above):

•All patients – We administer dexamethasone (4 to 8 mg IV after induction) and 5-HT₃ antagonists (eg, ondansetron 4 mg at the end of surgical procedure).

•High-risk patients – For patients at very high risk of PONV (eg, history of motion sickness, history of previous PONV, high opioid requirements for pain relief), we also use preoperative transdermal scopolamine (1.5 mg transdermal patch). In addition, we use total intravenous anesthesia (TIVA) with propofol.

•Rescue therapy – For rescue therapy in the immediate postoperative period, we administer low-dose promethazine (6.25 mg IV, slowly) or dimenhydrinate (1 mg/kg IV).

●Complications of laparoscopy

•Hemodynamic (eg, hypotension, hypertension, and arrhythmias) and pulmonary complications (eg, hypoxia, hypercarbia) can occur as a result of the physiologic effects of laparoscopy (table 3 and table 4 and table 5). (See 'Hemodynamic complications' above and 'Pulmonary complications' above.)

•Rare but significant complications can occur, including traumatic vascular and organ injury, CO₂ embolism, capnothorax, and capnomediastinum. Treatment is supportive and may require release of the pneumoperitoneum and conversion to open surgery (table 4 and table 6). (See 'Carbon dioxide insufflation' above.)