Robotic and Laparoscopic Surgery

Question 1

Laparoscopic vs. Lapartotomy

Answer 1

• 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.
• Laparoscopy requires insufflation of intraperitoneal or extraperitoneal gas, usually carbon dioxide (CO2), to create space for visualization and surgical maneuvers.
• Robotic surgery is usually performed laparoscopically and is most commonly used for gynecologic and urologic surgery, although use is expanding in other specialties.

Question 2

Anesthetic concerns re laparoscopic

Answer 2

• Anesthetic concerns for patients undergoing laparoscopic and robotic surgery include the physiologic effects of the pneumoperitoneum, absorption of CO2, and positioning required for surgery. In addition, some laparoscopic/robotic procedures take longer than the open alternative.

Question 3

Techniques - requires what?

Answer 3

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 by 1) blindly using a needle, or 2) by placing a port under direct vision through a small subumbilical incision.

Question 4

Insufflation

Answer 4

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.
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.

Question 5

Robotic techniques

Answer 5

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.
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.

Question 6

Preop eval

Answer 6

Patient selection for laparoscopic or robotic surgery depends on clinical judgement and assessment as to whether a patient may tolerate pneumoperitenum or prolonged periods in an extreme position (e.g. steep trendeleburg)
Ex: history of significant cardiovascular comorbidity, cerebrovascular accident, poor pulmonary function, pulmonary hypertension, glaucoma

Question 7

Laparoscopic and Robotic Surgery: Cardiovascular changes - SVR and MAP

Answer 7

Question 8

Filling pressures

Answer 8

Question 9

Rhythm

Answer 9

Question 10

Positioning

Answer 10

Question 11

Respiratory changes - pulmonary mechanics

Answer 11

Changes in pulmonary mechanics –
Pneumoperitoneum causes cephalad displacement of the diaphragm which reduces FRC and pulmonary compliance, resulting in atelectasis and increased peak airway pressures.

Question 12

CO2 absorption

Answer 12

CO2 Absorption - CO2 is highly soluble and is rapidly absorbed into the circulation during insufflation for laparoscopy.

Question 13

ETT position

Answer 13

Endotracheal tube position – Pneumoperitoneum and Trendelenburg positioning may result in mainstem endobronchial migration of the endotracheal tube, hypoxia, and high inspiratory pressure. Also, endotracheal tube cuff pressure increases in some patients during laparoscopy.

Question 14

Renal blood flow

Answer 14

– The creation of a pneumoperitoneum results in reduction in renal perfusion and urine output

Question 15

Cerebral blood flow

Answer 15

– Increased intraabdominal and intrathoracic pressures, hypercarbia, and Trendelenburg positioning can all increase cerebral blood flow (CBF) and intracranial pressures (ICP)

Question 16

Intraocular pressure

Answer 16

– Intraocular pressure (IOP) increases with pneumoperitoneum and increases further when the patient is positioned in Trendelenburg

Question 17

Anesthetic Management

Answer 17

• In most cases, general anesthesia is used for laparoscopy and robotic surgery; however,** neuraxial **anesthesia has been used for short procedures in reverse Trendelenburg (necessitating a T4 level)
• Furthermore, an ETT is frequently used; however, there are a number of studies and case reports describing the safe use of second-generation SGAs for laparoscopic procedures
• Second-generation SGAs allow the use of higher airway pressure without leak and have esophageal vents to minimize the chance of aspiration.
• When the arms are tucked, an additional IV may be placed, and an arterial line may be considered for blood sampling
• An orogastric tube should be placed and suctioned to decompress the stomach prior to needle or trochar insertion

Question 18

Positioning - common

Answer 18

Laparoscopy is often performed in extreme reverse Trendelenburg (eg, for cholecystectomy or gastric surgery) or extreme 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).

Question 19

Positioning Devices

Answer 19

• 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 procedures requiring reverse Trendelenburg positioning.
• Nonslip padding and cross-body taping are options for preventing sliding on the operating table during steep Trendelenburg positioning.
• 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
• Testing for sliding with maximal Trendelenburg positioning can be done prior to surgical prep and drape and confirm that taping does not restrict chest excursion or affect ventilation.
• Pressure points should be padded, as should the plastic connectors on IV tubing and monitoring devices.
• 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..

Question 20

N2O

Answer 20

N2O diffuses into air-containing closed spaces over time and can lead to bowel distention, which can theoretically impair surgical exposure and dissection

Question 21

NMBs

Answer 21

Neuromuscular blocking agents (NMBAs) are administered during abdominal surgery to facilitate endotracheal intubation and to improve surgical conditions.

Question 22

Vent management

Answer 22

The dynamic changes in pulmonary function during laparoscopy require intraoperative adjustment of mechanical ventilation.
Example: 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 12 breaths/minute.
The anesthesia professional can adjust these settings to maintain ETCO2 at approximately 40 mmHg and oxygen saturation (SaO2) >90 percent.

Question 23

Optimize ventilation: high peak pressures

Answer 23

For peak pressures over 50 mmHg –> set the I:E ratio at 1:1.

Question 24

Hypercarbia

Answer 24

• Consider increasing the respiratory rate, rather than the tidal volume, to increase minute ventilation and compensate for CO2 absorption while avoiding barotrauma. We accept mild hypercapnia (ie, end-tidal CO2 approximately 40 mmHg)
• For hypercarbia (ie, ETCO2 >50 mmHg) despite hyperventilation, then examine for signs of subcutaneous emphysema.
  If hypercarbia and/or hypoxia persist, we discuss conversion to open surgery.

Question 24

hypoxia

Answer 24

• For hypoxia (ie, SaO2 <90 percent), then auscultate breath sounds bilaterally to rule out bronchospasm and endobronchial intubation, then 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).
• If hypoxemia and/or high peak airway pressures persist for patients in Trendelenburg position, then reduce the degree of tilt and/or reduce the insufflation pressure (eg, from 15 to 12 mmHg or less).

Question 24

Vent Mode

Answer 24

Pressure control with volume guarantee, where available, can be used to limit peak airway pressure while maintaining constant ventilation

Question 25

Driving pressures

Answer 25

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

Question 26

Alveoli

Answer 26

Alveolar recruitment in conjunction with high PEEP (15 cm H2O) applied before the onset of pneumoperitoneum may prevent the alveolar collapse.

Question 27

Optimize ventilation: high peak pressures

Answer 27

For peak pressures over 50 mmHg –> set the I:E ratio at 1:1.

Question 28

I:E

Answer 28

Increasing the inspiratory to expiratory (I:E) ratio may be beneficial in steep Trendelenburg position during laparoscopy.

Question 29

Obesity

Answer 29

In some obese patients, 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. This suggests that pressure-controlled modes may not be appropriate for many obese patients, as the increased airway opening pressures may prevent ventilation unless very high peak pressures are used.

Question 30

Fluids

Answer 30

Perioperative fluid therapy is one of the major factors known to influence postoperative outcomes after abdominal surgery. Restrictive fluid therapy with avoidance of fluid excess improves outcome after major gastrointestinal surgery, with avoidance of bowel edema and interstitial fluid accumulation.

Question 31

PONV

Answer 31

Laparoscopy has been identified as a risk factor for PONV. 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.

Question 32

Pain

Answer 32

• 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 and is less than the corresponding open procedure, but the degree of pain depends on the specific surgery.
• Pain after laparoscopy can often be managed effectively with acetaminophen, nonsteroidal antiinflammatory drugs (NSAIDs) or cyclooxygenase2 (COX2)-specific inhibitors, and dexamethasone.
• Routinely infiltration of the incisions with local anesthetic (LA) at the time of wound closure can be helpful. 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, oxycodone).

Question 33

TAP Block

Answer 33

For hybrid or laparoscopy-assisted surgical procedures with longer incisions, interfascial plane blocks such as transversus abdominis plane (TAP) block may be beneficial. Alternatively, surgical site infiltration has also been shown to provide good pain relief.

Question 34

Hemodynamic changes during insufflation

Answer 34

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.

Question 35

Treatment for HD changes with insufflation

Answer 35

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.

Question 36

During surgery complications

Answer 36

1. Hemorrhage
2. Hyperventilation
3. Positioning

Question 37

Hemorrhage

Answer 37

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

Question 38

Hyperventilation

Answer 38

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.

Question 39

Positioning

Answer 39

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.

Question 40

Hypercarbia

Answer 40

Hypercarbia – It may be necessary to increase ventilation during laparoscopy to compensate for CO2 absorption.
When severe hypercarbia occurs during laparoscopy despite aggressive hyperventilation:
the patient should be examined for signs of subcutaneous emphysema (ie, crepitus over the abdomen, chest, clavicles and neck).

Question 41

Subcutaneous Emphysema - risk factors

Answer 41

Risk factors for subcutaneous emphysema includes surgery lasting longer than 200 minutes, the use of six or more surgical ports, patient age >65, and nissen fundoplication surgery

Question 42

Management of subcutaneous emphysema

Answer 42

When external swelling is severe, options include the following: Laryngoscopy to assess airway edema while the patient is anesthetized., extubation over a tube changer, and delayed extubation for several hours, with the patient positioned head-up, to allow resorption of CO2.
reduced insufflation pressure or conversion to open surgery may be required

Question 43

Hypoxia

Answer 43

• 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

Question 44

Hypoxia Management

Answer 44

1. The chest should be auscultated for the quality and presence of bilateral breath sounds to rule out bronchospasm and endobronchial intubation.
2. Initial treatment includes an increase in inspired oxygen concentration.
3. 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.
4. If refractory hypoxemia occurs, the pneumoperitoneum should be released.

Question 45

Gas Embolism

Answer 45

Gas embolism—Venous gas embolism is extremely common during laparoscopy, though clinically significant emboli are rare.
Gas embolism can occur via two mechanisms.

CO2 entrainment is possible if a vein is severed or disrupted during surgery, allowing the gas under pressure access to the circulation.
Direct venous injection of CO2 with the Veress needle can result in rapid, high-volume CO2 embolism at the time of abdominal insufflation.

Question 46

Gas Embolism S&S

Answer 46

Signs of gas embolism include:
- unexplained hypotension
- abrupt reduction of ETCO2
- hypoxemia
- 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.

Question 47

Gas Embolism - treatment

Answer 47

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

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.

Question 48

Instrument Complications

Answer 48

• Up to half of serious surgical complications occur during placement of the Veress needle or an access port. 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.

Question 49

Steep Trendelenberg complications

Answer 49

• Prolonged steep Trendelenburg positioning can cause conjunctival, nasal, and laryngopharyngeal edema and may result in increased upper airway resistance
• Both minor (ie, corneal abrasion) and significant (ie, ischemic optic neuropathy) ocular injuries have been reported after laparoscopy performed in steep Trendelenburg position.
• Patients who undergo prolonged laparoscopy are at risk for position-related nerve injury and even compartment syndrome. Pressure points, plastic tubing connectors, monitoring cables, and leg supports for lithotomy positioning should all be padded.