ANAESTHESIA FOR ROBOTIC PROCEDURES

Dr Azrin Mohd Azidin, Dr Noorul Hana Sukarnakadi Hadzrami, Dr Amiruddin Nik Mohamed Kamil

Department of Anaesthesia and Intensive Care, Hospital Kuala Lumpur

CONTENTS

Introduction

A) Anaesthesia for Urological Procedures

1. Robotic prostatectomy/Cystectomy (and pelvic procedures)

1.1. Anaesthetic Considerations

1.2. Problems associated with Trendelenberg position

1.3. Conduct of Anaesthesia

1.3.1. Preoperative assessment

1.3.2. Positioning

1.3.3. Intraoperative management

1.4. Ventilatory srategies and targets

1.5. Fluid management

1.6. Extubation and postoperative management

2. Robotic pyeloplasty

B) Anaesthesia for Gastrointestinal Procedures

1. Robotic gastrectomy

1.1 Anaesthetic Considerations

1.2 Positioning

1.3 Anaesthetic Technique

C) Anaesthesia for Endocrine Procedures

1. Robotic Thyroidectomy

1.1 Anaesthetic Considerations

1.2 Positioning

1.3 Anaesthetic Technique

Conclusion

Reference

INTRODUCTION

Robotic surgery refers to a surgical technology that works on a computer-assisted

electromechanical device as an interface between the surgeon and the patient.

It involves mechanically translating surgeon’s movements from a visually

enhanced master console to a remote surgical cart which houses mechanical

arms that mimics the same movements on the patients with a higher degree of

precision and control than is normally possible.

In the last 5 years , there have been tremendous advancement in the use of

robotic technology for various surgical procedures. Although its use were initially

confined to prostatectomies, with widespread advances and training, robotic

procedures have now expanded to other surgical specialties such as

cardiothoracic, endocrine, colorectal and gynaecolology.

A) Anaesthesia for Urological Procedures

1. Robotic Prostatectomy/Cystectomy (and pelvic surgeries)

- The most common procedure done and the most physiologically demanding

for patients. - Surgically similar to laparoscopic technique with the difference of more

presicion and stability for dissection of critical structures due to the

tridimensional view from the surgeon’s console. - The problems associated are a consequence of 3 main factors.

• Extreme steep Trendelenberg position • Insufflation of carbon dioxide (CO2) • Spatial restrictions due the bulk of the surgical cart

1.1 Anaesthetic Considerations

• Altered Physiology due to steep Trendelenberg position

• Access to patient

- Restricted access due to the bulk of surgical cart and position of

assisstants and equipments

• Airway

- displacement of ETT due to mediastinal movement

- oedema of the head and neck due to prolonged Trendelenberg

position

• Position of patients

- supine with arms by the side and strapped to OT table or casted on

a ‘bean bag’ ( vacuum applied beaded mattress)

- legs held apart in lithotomy position with padded leg rests

• Problems due to laparoscopic procedures

- Pneumoperitoneum

- CO2 insufflation and hypercarbia

Three components of robotic operating module

Surgeons Console

Patient Cart

Vision Cart

- moderate hyperventilation may result in pneumothorax,

pneumomediastinum and more commonly subcutaneous emphysema. (

Due to hyperventilation at high inspired pressures with pneumoperitoneum)

- possibility of visceral injury

• Problems due to prolonged surgery

- Hypothermia

• Monitoring of systems

• A(airway)

• B(blood gases)

• C(cardiovascular system, central nervous system, CO2, compliance

of the lung)

• D(diuresis at the end of surgery)

• E ( entrapment of plexuses/nerves)

• F ( fluids consideration- type and volume)

• Venous Gas embolism

1.2 Problems associated with Trendelenberg position

1.2.1 Central Nervous System

- Increase in interstitial oedema with resultant cerebral oedema

- increased cerebral venous pressure

- reduced cerebral blood flow

- increased intraocular pressure

- overall increase in intracranial pressure

- a reported case of cerebral hemorrhage with neurological deficit

- clinical swelling of head and neck, oedematous face, conjunctivae and

tongue is almost always observed.

1.2.2 Respiratory System

- abdominal contents push the diaphragm cephalad

- worsened by obesity

- mediastinum is displaced upward

- increased pulmonary blood content (increased capacitance and

recruitment of intrapulmonary vasculature)

- reduced Functional Residual Capacity

- most vasculature in West zone 4 condition (Pa>Pi>Pv>PA)

- development of pulmonary interstitial oedema

- prone to atelectasis

- reduced lung compliance

- increased V/Q mismatch

- -causes an increase in PA-a gradient

- -displacement of ETT cephalad or distally (risk of dislodgement or

endobronchial intubation)

- changes are made worse with pneumoperitoneum

1.2.3 Cardiovascular System

- decrease in heart rate as a result of vagal reflex

- increase in central venous pressure

- increased pulmonary capillary wedge pressure

- increased cardiac filling pressures and volume (increased venous return

and stroke volume)

- increased myocardial oxygen demand

- decreased A-V oxygen difference

- cardiac output and mean arterial pressure may be unchanged or slightly

increased

- caution in patients with myocardial disease

- changes are made worse with pneumoperitoneum

- increased systemic and pulmonary vascular resistance, mean arterial

pressure and heart rate can be due to hypercarbia.

1.2.4 Gastrointestinal and metabolic derangement

- worsened with pneumoperitoneum

- reduced blood flow to organs

- Increase in lactate levels

- altered liver enzymes

- splanchnic ischaemia and reperfusion can lead to worsening acidosis and

necrosis

- oliguria due to mechanical pressure on renal parenchyma

1.2.4 Peripheral nerve

- compressed or traction on nerve/plexus may cause neuropathy

- incidence of 0.25%

- lingual and buccal nerve neuropathy were documented

- common peroneal nerve can be injured due to inappropriate padding

- median nerve palsy being one of the more common lesions

1.3. Conduct of anaesthesia

1.3.1. Preoperative assessment

- All patients are reviewed and optimized clinically

- Special attention must be made to patients with myocardial and

respiratory diseases.

• Cardiac assessment with echocardiography, stress test or perfusion

scan must be done for risk stratification.

• Lung function test for patients with respiratory disease, bronchodilator

therapy and aggressive lung expansion physiotherapy must be done

preoperatively.

- Appropriateness for procedure must be discussed with the surgeons.

- Pre-emptive analgesia (NSAIDs) and acid prophylaxis to be given prior to

surgery.

1.3.2. Intraoperative Management

- Induction of anaesthesia is via the intravenous technique using induction

agents appropriate for the patient according to his clinical status.

- After induction, maintenance anaesthesia is via balanced technique with

inhalational agent at 0.9-1.2 MAC in 50% 2L/min O2/air mixture with

intermittent relaxant and opioid boluses.

- Two (2) 16G branulas are inserted with extension tubings of appropriate

length, taped around the hands and brought upwards toward the head

end. The tubings are positioned in such a way that they will not be kinked

during positioning.

- A 12-14 Fr nasogastric tube and a temperature probe are inserted.

- An arterial line is inserted using a 20G branula under aseptic technique,

and the monitoring line is also secured and positioned around the hands

and brought towards the head end together with NIBP and pulse oximeter

cables.

- Central Venous Pressure monitoring is inserted only if there is an indication.

- Both upper limbs are wrapped, sufficiently padded and strapped into

position with the aid of vacuum-assisted beaded mattress. (bean bag).

- Temperature control is maintained with cotton wrappings of the extremities

and blanket, with the aid of the Bair Hugger system.

IV lines and monitoring are secured and brought upwards to the head end.

Note how the monitoring lines and intravenous tubings are brought around the covered upper limb towards the head end

1.3.3 Positioning of patients

- Patient is strapped supine with both arms by the side and the legs apart.

- Anaesthetic machine is positioned by the head end of patient.

- Intravenous lines with extension tubing and non-invasive/invasive

monitoring are secured and brought to the head end.

- After surgical cleaning and draping, CO2 pneumoperitoneum is instituted

at pressures between 15-20 mmHg for port insertion. These pressures will be

reduced to 10-15mmHg once all the ports have been inserted.

- OT table is tilted up to -45 degrees by slow increments into Trendelenberg

position and the robotic operating module (surgical cart) is docked over

the perineum.

Patient is placed into a steep Trendelenberg position prior to docking of surgical cart

1.4 Ventilation strategy and targets

- Both volume /pressure control ventilation can be used

- Ensure Peak Airway Pressure not exceeding 40mmHg (mean pressures <

25mmHg

- Normal tidal ventilation at 4-7 ml/kg

- Adequate minute ventilation to achieve EtCO2 not exceeding 40mmHg

(to achieve normocarbia)

- If airway pressures approaching 40mmHg with respiratory rates of 18-20, our

data showed that lengthening the inspiratory time and shortening the

expiratory time (I:E ratio of 1:1.5 or higher), resulted in an increase in tidal

volume and minute ventilation; thus bring CO2 to a more manageable

level without further increase in airway pressures.

- In instances whereby peak airway pressures and or CO2 control is difficult;

allow moderate hypercarbia (EtCO2 up to 45)

- If there is difficulty in achieving ventilatory target, rule out ETT migration,

kinking or obstruction from secretions or spasm.

- Inform and discuss with surgeons if there is difficulty.

1.5 Fluid management

- Boluses of IV fluids to be preferably given while in supine position. (Which

are in the beginning and towards the end of surgery).

- Injudicious fluid management during trendelenberg position will result in

increase of likelihood of interstitial oedema. Urine production and leakage

during bladder neck dissection will also obscure the surgical field.

- Limit fluid to 1-1.5 litres. (Korean experience: Robotic Radical Prostatectomy

takes about 2.5-3 hours. Use infusion rate of less than 500 ml/hour.)

- Administering colloids will reduce the likelihood of oedema formation when

compared to purely crystalloid infusions.

- The choice of solution between saline or lactate-containing solutions

should be guided by frequent electrolyte analysis. (lactic acidosis can be

due to reduced organ perfusion during trendelenberg position with direct

mechanical effect from pneumoperitoneum. This may need frequent fluid

boluses intraoperatively).

- Be aware of haemodynamic changes which occur especially during initial

stages of pneumoperitoneum and also during initiation of Trendelenberg

position. These changes are usually transient and return to baseline

gradually over the following twenty to thirty minutes. There has been a

reported case of bradycardia and asystole following rapid change into

Trendelenburg position.

- Bleeding may occur but it is rarely catastrophic. Generally it is within the

range of 300-500 ml. Suction container is usually filled with blood mixed

with irrigation fluid and urine from bladder neck dissection. Be aware that

stereoscopic view is magnified, and bleeding may be overestimated.

- The most common complication is head and neck oedema followed by

subcutaneous emphysema. These complications are usually self -limiting and

dependant on the duration of surgery.

1.6 Extubation and Post-Operative Management

- Airway oedema almost always occurs and a leak test must be performed to

ensure safety for extubation. Re-intubation may be difficult if significant airway

oedema exists. In this case, it is advisable to keep the patient intubated and

ventilated until oedema subsides.

- Conscious level may also be depressed as a consequence of cerebral

oedema.

- Normal criteria for extubation apply and muscle relaxants need to be

reversed.

- All extubated patients are given PCA morphine as per standard protocol.

- Acid prophylaxis (IV Ranitidine 50 mg 8H) is usually continued.

- Consider overlapping IV Paracetamol or IV Tramadol before discontinuation

of PCA Morphine.

- At the moment, all robotic patients are being monitored in the Intensive Care

Unit.

2. Anaesthesia for robotic pyeloplasty/ nephrectomy

- All considerations are similar except for patient’s positioning.

- Pyeloplasty procedures are of a shorter duration and the patients are placed

in the lateral position.

- Patients are more accessible to anaesthesiologists as the arms are placed on

arm-boards and arm-rests to the patient’s contralateral side from the

operating area.

- Ventilation pressures are much lower than prostatectomies. However, high

enough pressures is still required to ventilate the dependent lung. V/Q

mismatch can still occur.

- Fluid admiistration is as per normal requirement for surgery. ( Intraoperative

maintenance 2-4 ml/kg/hr)

- Bleeding is normally minimal in pyeloplasty, slightly more with nephrectomy.

- Analgesia is multimodal. Less is required compared to prostatectomies.

- All patients are normally extubated postoperatively.

B) Gastrointestinal robotic procedures

1. Robotic Gastrectomy

- The most common procedure is for gastric carcinoma either total or

subtotal gastretomy with duodenal anastomosis. For lower gastrointestinal

surgery, the most common procedures are for colonic carcinoma

1.1 Anaesthetic considerations;

* (IV) access to patients- both arms by the side

* laparoscopic surgery- CO2 pneumoperitoneum

* long surgery- lower gastrointestinal surgery e.g carcinoma resection

may take 6-7 hours; stomach surgery takes 3-4 hours

* positioning- head end up to about 30 degrees; patient is strapped

* monitoring

- Pre anaesthetic interviews are done on patients with moderate to severe

medical illness. In other cases, premedication rounds are done by

reviewing patients electronic medical records only, with interviews done

when the patients are in the pre anaesthetic area.

- No routine premedication are usually given, except for selected cases.

Glycopyrrolate (40mcg/kg) is given in the pre anaesthetic area.

1.2 Positioning of patient

- Patient’s is strapped supine with both arms by the side.

- Anaesthetic machine is positioned by the side of patient.

- An 18G intravenous cannula with extension tubing for fluids with double 3

way connector for infusions is inserted.

- Intravenous lines with extension tubing and non-invasive monitoring are

taped and secured and brought to the head end.

A case of gastrectomy being prepared for surgery

1.3 Anaesthetic Technique

- Induction of anaesthesia is via the intravenous route using 1mcg/kg of

remifentanil, 2mg/kg of propofol and 0.6-0.9mg/kg of rocuronium.

- Patient is started on intravenous infusion of remifentanil (20 mcg/ml)

titrated and rocuronium at 10mg/h.

- Maintenance anaesthesia is via balanced anaesthetic technique, with

remifentanil and rocuronium infusion with sevoflurane at 0.9-1.2 MAC in 50%

oxygen-air mixture at 2.0L/min.

- Routine non invasive monitoring include non invasive blood pressure, pulse

oximetry, electrocardiography.

- After surgical cleaning and draping, CO2 pneumoperitoneum is instituted

at pressures between 10-15 mmHg for port insertion.

Remifentanil and rocuronium infusion being used intraoperatively

An ongoing case of gastrectomy

- OT table is tilted head end up by 30 degrees. (Reverse Trendelenberg

position) and the Robotic operating module (surgical cart) is docked over

the head end of the patient.

Docking of surgical cart for robotic gastrectomy

- Ventilation strategy and targets;

Peak Airway Pressure not exceeding 30mmHg

Normal tidal ventilation at 7-10ml/kg

Adequate minute ventilation achieving EtCO2 of not exceeding

40mmHg

- IV fluids;

normal requirements

usually 80-90% of open technique

- Temperature control are maintained with cotton wrappings of the

extremities and blanket, with the aid of the Bair Hugger system.

- Intraoperative problems are usually minimal, and minimal changes in vital

signs are anticipated. Bleeding can occur rarely but not usually

catastrophic.

- Muscle relaxant infusion is stopped 30-40 minutes prior to estimated time

the surgery ends.

- A single use Patient Controlled Analgesia (PCA) device ( containing

fentanyl 1000mcg and ondansetron 16mg in 100 ml saline preparation)

with basal infusion is also started at around the same time. (via accufusor- 2

ml /h basal infusion with 0.5ml bolus and a lock-out time of 15 minutes)

Accufusor for PCA fentanyl

- Remifentanil infusion is stopped at the end of the last surgical suture.

- Sevoflurane in 50% oxygen-air mixture is dialled off and high flow oxygen

100 % is given.

- Neostigmine 2.5mg with glycopyrrolate (20 mcg/kg) is administered as

NDMR reversal at the end of surgery.

- Patient is normally extubated well and pain free, with a good recovery

profile.

- Patients will be observed in the recovery area for 30-60 minutes and later

discharged to the wards once satisfy the discharge criteria .

- APS nurses will review post operative PCA requirements which will normally

be stopped after 24-48 hours depending on the type of surgery.

Operation room set up for robotic surgery

C) Endocrine robotic procedures

1 Robotic Thyroidectomy

- The most common procedure is for thyroid carcinoma either total or

hemithyroidectomy. Other procedures include parathyroidectomy or

adrenal surgery.

1.1 Anaesthetic considerations;

* (IV) access to patients- the left arm is put by the side

* positioning- the right arm is abducted and extended above the

head on an elevated arm rest. Back and neck is extended on a

special triangular pillow

- Pre anaesthetic interviews are done on patients with moderate to severe

medical illness. In other cases, premedication rounds are done by

reviewing patients electronic medical records only, with interviews done when

the patients are in the pre anaesthetic area.

- No routine premedication are usually given, except for selected cases.

Glycopyrrolate is given in the pre anaesthetic area.

1.2 Positioning of patient

- Patient’s is strapped supine with usually the left arm by the side.

- Anaesthetic machine is positioned at the head end of patient.

- An 18G intravenous cannula with extension tubing for fluids with double 3

way connector for infusions is inserted.

- Intravenous lines with extension tubing and non-invasive monitoring are

taped and secured and brought to the head end.

Extension pillow for robotic thyroidectomy

Arm rest for ipsilateral upper limb in robotic thyroidectomy

Patient’s position after placement of extension pillow

Patient’s position after placement of arm rest

1.3 Anaesthetic Technique

- Induction of anaesthesia is via the intravenous route using 1mcg/kg of

remifentanil, 2mg/kg of propofol and 0.6-0.9mg/kg of rocuronium.

- Patient is started on intravenous infusion of remifentanil (20 mcg/ml)

titrated and rocuronium at 10mg/h.

- Maintenance anaesthesia is via balanced anaesthetic technique, with

remifentanil and rocuronium infusion with sevoflurane at 0.9-1.2 MAC in 50%

oxygen-air mixture at 2.0L/min.

- Routine non invasive monitoring include non invasive blood pressure, pulse

oximetry, electrocardiography.

- After surgical cleaning and draping. Incision and dissection is via the

axilla/pectoral region extending to the neck.

- Robotic operating module is docked over the contralateral side of the

incision.

An ongoing case of robotic thyroidectomy

- Ventilation strategy and targets;

Peak Airway Pressure not exceeding 30mmHg

Normal tidal ventilation at 7-10ml/kg

Adequate minute ventilation achieving EtCO2 of not exceeding

40mmHg

- IV fluids;

normal requirements

- Temperature control are maintained with cotton wrappings of the

extremities and blanket, with the aid of the Bair Hugger system.

- Intraoperative problems are usually minimal, and minimal changes in vital

signs are anticipated

- Muscle relaxant infusion is stopped 30-40 minutes prior to estimated time

the surgery ends.

- Patient Controlled Analgesia (PCA) is usually not required.

- Remifentanil infusion is stopped at the end of the last surgical suture.

- Sevoflurane in 50% oxygen-air mixture is dialled off and high flow oxygen

100 % is given.

- Neostigmine 2.5mg with glycopyrrolate will be administered as NDMR

reversal at the end of surgery.

- Patient is normally extubated well and pain free, with a good recovery

profile.

- Patients will be observed in the recovery area for 30-60 minutes and later

discharged to the wards once satisfy the discharge criteria .

- For thyroidectomy, IV ketorolac is given as supplemental analgesia, and no

PCA fentanyl is usually given.

Conclusion

The use of robotics for various surgical disciplines are expanding. Even though

much surgical benefit is observed, there are many challenges for the

anaesthesiologists in management of such cases. On top of existing potential

complications due to the technique itself, shortcomings due to individual surgical

learning curves also influence patients’ outcome. In anticipation of the rising

trend towards robotic procedures, the anaesthesiologists must be well equipped

to confront this changing face of surgery.

References:

1. A brief review: anaesthesia for robotic prostatectomy

Sarkis Baltayian J Robotic Surg (2008) 2: 59-66

2. Anaeshesia for Robot-Assisted Laparoscopic Surgery

Michael Irvine; Vishal Patil MD. Cont Edu Anaesth Crit Care & Pain. 2009;9

(4): 125-129

3. An Audit on Anaesthesia for Robotic Surgery in Kuala Lumpur General

Hospital 2008-2010. An Observational Study.

Amiruddin N.M. Kamil, Azrin M. Azidin, Noorulhana S. Hadzarami