Case 38 - laproscopic robotic prostatectomy

Question 1

what are your primary anestheic concerns for robotic assisted laproscopic radiacl prostatectomy (RALP)?

Answer 1

1. physiologic effects of pneumoperitoneum in t-berg
2. restricted access to pt due to robot
3. prevention or tx of complications 2/2 t-berg, exaggerated lithotomy, pneumoperitoneum

Question 2

What are the cerebrovascular effects of pneuoperitoneum in steep t-berg position?

Answer 2

1. decrease cerbal vascular drainage –> increase CBV and increase CSF
2. increase ICP

• pneumoperitoneum –> increase intrabdominal pressure –> transmits to thorax and superior vena cava –> hinders cerebral venous drainage –> increases CBV –> increase ICP
• pneumoper -> inc PaCo2 -> cerebral vasodilate
• t-berg also increases ICP due to poor cerbreal venous drainage
• CPP does not appear to be compromised.

Question 3

Describe the respiratory effects of pneumperitoinum in steep t-berg position?

Answer 3

1. Increase peak airway and plateau pressures
2. decrease FRC
3. decrease pulmonary compliance

• pneumoperitoneum increase intrabdominal pressure –> decrease pulm compliance and tidal volumes –> increase peak airway and plateau pressure
• along with steep t-berg –> decrease FRC, decrease pulm compliance, redispose to atelectasis
• due to t-berg, pulmonary blood increases in lungs, at risk for interstital edema 2/2 increase hydrostatic pressure (lung below level of heart)

Question 4

what would you do to maintain minute ventilation in a patient with pneumoperitoneum in t-berg position?

Answer 4

• will need to increase peak airway pressure to overcome airway resistance and allow gas flow into lungs.
  
  • avoid extreme high PAP due to risk of barotrauma
• permissive hypercapnia
• increase RR to maintain constant minute ventilation (since tidal volume will decrease due to position)
• consider I:E ratio change

Question 5

What are the hemodynamic effects of pneumoperitoneum in steep t-berg position?

Answer 5

1. decrease or unchange HR, CO, MAP
2. increase CVP and SVR
3. increase stroke volume/preload

• pneumoperitoneum can cause aortic compression –> increase afterload/SVR
• CVP increase with steep t-berg due to dependent flow of blood (gravity)
• be mindful that insufflation can cause vagal reflex (bradycardia)

Question 6

What are complications of pneumoperitoneum and steep t-berg posistion during RALP?

Answer 6

• CO2 sub-q emphysema
  
  • crepitus
  • hypercapnia
  • pneumothorax / mediastinum / pericardium
• venous gas embolism
  
  • sudden cardiovascular collapse
  • lose CO2 tracing
• positioning
  
  • slide off table
  • brachial plexus injuries/peripheral nerve injury
• facial/laryngea/pharyngeal edema
  
  • difficult extubation
  • re-intubating difficult
• ocular injuries
  
  • ION
  • abrasion

Question 7

what are the complications of CO2 subcutaneous emphysema?

Answer 7

CO2 sub-q emphysema

1. crepitus (can compress airway)
2. hypercarbia (increase RR)
3. pneumothorax / mediastinum / pericardium

• crepitus can be felt. swelling of neck can interefere with breathing, hypercapnia causes elevated RR
  
  • if pt has severe crepitus —> mech ventilate until resolved

Question 8

The patient during RALP has acute hypotension, you suspect venous gas emboli, what do you do?

Answer 8

venous gas embolism

• CO2 used for insufflatoin, more solubule then air therefore it is less threatening to cause air lock then similar sized emboli composed of air
• Co2 gas embolism can occur with intial insufflation and dissection of deep dorsal venous cmplex

MGMT

• notify sx to stop immedietly, desufflate abdomen, undock and remove robot for pt access
• maintain steep t berg and tilt patient left side down (shifts emboli away from RVOT)
• d/c N2O, hyperventilate with 100% to facilitate removal of CO2
• can attempt to aspirate gas with CVC
• ACLS if necessary

Question 9

At the end of the case, you extubate the patient and he experiences SOB and stridor, you suspect laryngeal edema. How could you have prevented this?

Answer 9

Facial/pharyngeal/larygeal edema

• occurs with combo of steep t berg and pneumoperitoneum
• increase IV fluids, reduced venous outflow due to pneumopertioneum, and steep berg causing pooling of head/neck contribute to this

Prevent

• restrict fluids, minimize time in steep t berg
• assess for facial and conjunctival edema (surrogate for airway edema)
• cuff leak test
• when in doubt, keep patient intubated + mech vent, sitting position, diuretics, and delay extubation until edema resolves
• consider extubation over airway exchange catheter
• if extubated patient experiences SOB and stridor, suspect airway edema and emergently reintubate.

Question 10

what are some causes of ischemic optic neuropathy in RALP patients?

Answer 10

ION

• typically occurs in spine cases 2/2 prone position, hypotension, acute blood loss
• can occur in cases of severe t-berg as well

ION in RALP

• decrease venous ocular outflow - steep t berg and pneumperito –> increase venous pressure in head/neck due to pooling of blood
• decrease arterial flow –> due to increase backflow of venous pressure which can increase IOP
• increase PaCo2 can cause vasodilation and increase IOP

Question 11

what are preanesthetic concerns for patients presenting for RALP?

Answer 11

patients are typically > 60 and have comorbid conditions

• preexisting neurological deficits
  
  • at risk for brachial plexus/peripheral nerve injury
  • document deficits, have awake patient in lithotomy patient to see if they r comfortable
• CAD
  
  • cardiac reserve, stress test?, echo?, PCI/DES/BMS?
• COPD
  
  • patients may have lung bullae/blebs
  • sx associated with high PAP –> barotrauma
• obesity
  
  • can slide off table
  • high incidence of CAD, pulm dysfunciton, DM (neuro deficits)

Question 12

anesthetic technique for RALP?

Answer 12

• General anes with ETT
  
  • controlled ventilation required
  • main stem with pneumoper and t berg (abdominal contents shift diaphragm upwards)
• invasive lines +/-
  
  • dependent on comorbid conditions
  • place before robot is docked (limited access)
• muscle relaxation
  
  • required to faciliate pneumoperitoneum/surgical exposure

Question 13

what is your fluid managment going to be for RALP sx?

Answer 13

avoid excessive fluid administration

• at risk for facial/laryngeall/pharyngeal edema
• may also obscure surgical view during vesicourethral anastomosis