Anesthetic Considerations for Renal Procedures Flashcards
What population typically has GU procedures?
Elderly, with coexisting medical illnesses
What structure is very close to the urethral openings?
Obturator nerve
What is the significance of the proximity of the obturator nerve to the urethral opening?
Could be stimulated during a procedure causing the patient to box the surgeon in the head with their knees
At what MAP does auto regulation of the kidneys occur?
75-160mmHg
At what MAP will filtration cease?
Less than 60mmHg
What can occur if there is damage to the renal arteries?
Massive blood loss since they branch directly off of the aorta
Where are the kidneys located?
Retroperitoneal between T12-L4
What level block is required for somatic blockade for a renal procedure?
T8-L3
What sensory level blockade is required for anesthesia in a urethral procedure?
T10
How does anesthesia affect renal function?
Reversible decrease in RBF, GFR urinary flow and Na excretion
What position is frequently used in GU procedures?
Lithotomy
What are physiological consequences of the lithotomy position?
Decreased FRC, vital lung capacity lung volume and lung compliance
Altered venous return
What is the most common positional injury with use of the lithotomy position?
Peroneal nerve injury with loss of dorsiflexion
What are risk factors for peroneal nerve injury?
Lithotomy duration greater than 4hrs
BMI less than 20
Recent smoking history
What nerve injury can occur if the legs are not moved together?
Sciatic stretch
How does the extreme lithotomy position affect CPP?
Reduced CPP due to increased ICP, must have a high MAP to maintain perfusing CPP
What nerve injury is a concern in the extreme lithotomy position?
Brachial plexus injury from hyperabducted arms
What effects does a kidney rest have on ventilation?
Decreased FRC in the dependent lung
V/Q mismatch
Atelectasis in dependent lung
What is the effect of a kidney rest on the CV system?
Can cause decreased venous return
What is the hyper dorsal position?
Lateral oblique with table extended
What injuries are associated with the hyperextended dorsal position?
Brachial plexus injury
Peroneal and saphenous nerves
Ulnar nerve
Back strain
What is the hyperextended position?
Iliac crest over break in table and table extended then table tilted head down
Why does the hyperextended supine position cause facial and airway edema?
Causes an increase in the central venous volume
Since the operative site is above the level of the heart in the hyperextended supine, what is a complication in this surgery?
VAE
Why might a cystoscopy be performed?
Diagnosis of urological problems
Resection of bladder tumors
Access to urinary system
What level of regional anesthesia should be achieved with a cystoscopy?
T10 (umbilicus)
What is a major complication when a patient is in the lithotomy position for a prolonged period of time?
Rhabdomyolysis
At what size is it acceptable to resect the prostate?
Less than 60g
What are common causes of death in patients that have a TURP procedure?
MI, PE and renal failure
Why must fluid status be monitored so closely in patients having a TURP procedure?
Excessive absorption of irrigating fluid possible from large venous sinuses
When is absorption greatest in relation to prostate resection time?
15-35m
What is the maximum amount of time the surgeon should take to resect the prostate before major bleeding issues occur?
Should take less than 2hrs
What factors influence the amount of fluid absorbed by the sinuses?
The flow of the fluid which is determined by the height of the bag
Surgical time
What is a major complication of a TURP procedure?
Dilutional Syndrome
Why does absorption of excessive fluid cause the dilution syndrome?
The solutions are non-electrolyte and hypotonic
Why don’t solution used for TURP irrigation have electrolytes in them?
If there were electrolytes in the solution, caudry would disperse in the bladder
During a prostate resection, how much fluid is absorbed when the sinuses are opened?
20mL/min
What two laboratory values should be assessed if dilutional syndrome is being considered?
Sodium (hyponatremia) and Osmolality (hypoosmolar)
What physiologic signs are seen in dilutional syndrome?
CHF
Pulmonary edema
HoTN
How does dilutional syndrome affect RBCs?
Causes hemolysis administer hypotonic solution the cells swell and lysis
At what sodium level will the patient begin to show signs of confusion and restlessness?
120mEq
At what sodium level will the patient begin to show signs of somnolence and nausea?
115mEq
At what sodium level will the patient begin to show signs of seizures and coma?
110mEq
What is the treatment for dilutional syndrome?
3% saline IV no more than 100mL/hr until sodium is above 125mEq
Lasix
Why is it important to consider regional anesthesia with a TURP procedure?
General anesthesia can mask the symptoms associated with dilutional syndrome
What is the importance of the use of glycine in the irrigation fluid for a TURP procedure?
Hyperglycinemia from absorption leads to neurological changes since glycine is an inhibitory neurotransmitter in the CNS
What symptoms are associated with hyperglycinemia?
Nausea, malaise, vomiting, confusion, stupor, coma, blindness and siezure
What is the treatment for hyperglycinemia?
Lasix and supportive therapy
What is another complication of a TURP procedure from excessive volume being used for irrigation?
Bladder perforation
Why symptoms are felt by a sedated patient if a bladder perforation has occurred?
Abdominal pain
Nausea
Diaphoresis
How can a patient develop DIC from a TURP procedure?
Massive blood loss, difficult to track
Resection may release fibrinolytic enzymes
Dilutional thrombocytopenia
What reaction can be seen if the obturator nerve is stimulated?
External rotation and adduction of thighs
What is the only way to stop obturator nerve response?
Paralysis, spinal will not block the response
What can occur if a patient receive a TURP has a history of a spinal injury above T6-7?
Autonomic hyperreflexia
What are the triggers of autonomic hyperreflexia?
Surgical manipulation and bladder distention
What symptoms are seen with autonomic hyperreflexia?
Severe HTN, bradycardia and dysrhythmias
What can the anesthetic provider do to prevent autonomic hyperreflexia with a TURP procedure?
Spinal anesthesia blocks sympathetic response
What is the best monitor for detecting early signs of TURP syndrome or bladder perforation?
Mental status assessments
What is removed with a radical retropubic prostatectomy?
Prostate, seminal vesicles and part of the bladder neck removed
What is the benefit to performing a RRP?
Nerve sparing
What position is the patient placed in for a RRP?
Hyperextended supine
Why don’t patients typically tolerate a RRP with regional anesthesia?
Trendelenberg and large amounts of IV fluid may lead to upper airway edema
What are major complications associated with RRP procedure?
Massive blood loss with resection of the prostate
VAE
Nerve injury from position (brachial plexus)
Why is anesthetic management complicated in a radical perineal prostatectomy procedure?
Extreme lithotomy position, increase PIP and CVP make ventilation difficult
What is a benefit to the RPP procedure?
The abdomen is not entered
What is a consequence of the RPP approach?
Not generally nerve sparing, impotence
What is the most common cancer of the GU tract?
Prostate cancer
What habit is strongly associated with bladder cancer?
Cigarette smoking
What coexisting diseases are typically present with bladder cancer?
COPD and CAD
What tissues are taken out in a radical cystectomy in males?
Bladder, prostate, seminal vesicles and part of the urethra
What tissues are taken out in a radical cystectomy in female?
Uterus, cervix, ovaries, part of the urethra and anterior vaginal vault
What two ways can urine be diverted after a radical cystectomy?
Ileal conduit-urestomy bag on abdominal wall
Ileal pouch-pouch created inside abdominal wall to create a bladder
What anesthetic gas should be avoided with a radical cystectomy?
N2O
When is the peak incidence of adenocarcinoma of the kidney?
50-60 years old
Where can the adenocarcinoma of the kidney extend to in 5-10% of people that have it?
Renal vein and IVC asa thrombus
What are comorbidities associated with adenocarcinoma of the kidney?
Smoking is a risk factor
CAD & COPD
Why is it important to know if the adenocarcinoma has spread to the IVC prior to surgery?
Will require bypass for graft of SVC
What should the pneumoperitoneum be inflated to for a laparoscopic nephrectomy?
14-16mmHg, higher pressures can compress the vena cava
What is the initial treatment for testicular cancer?
Radical orchiectomy
If seminomas are present with testicular cancer, what is the post surgical treatment?
Retroperitoneal radiotherapy
If seminomas are not present with testicular cancer, what is the post surgical treatment?
Retroperitoneal lymph node dissection and Chemotherapy
What should the provider be looking for when traction is applied to the spermatic cord?
Reflex bradycardia
What are common reasons for a male to have a circumcision later in life?
Phimosis (obstruction of urine flow)
Recurrent infection
What procedures can be done for stress urinary incontinence?
Stamey Procedure
Raz bladder neck suspension
Sling procedure
What is the number one reason for a kidney transplant?
Insulin dependent diabetes in caucasians
What are the contraindications for a kidney transplant?
Infection and cancer
What should a patients potassium be prior to renal transplant?
Should be less than 5.5mEq
How could the provider anticipate the fluid status of a renal transplants patient?
Hypervolemia if done prior to dialysis
Hypovolemia if done after dialysis
Why is it important to give patients receiving a renal transplant a preoperative antibiotic?
Immunocompromised due to chronic uremia
What should be given prior to temporary clamping of the iliacs?
Heparin
Why is mannitol given after renal transplant?
Osmotic diuresis after reperfusion
What volatile should be avoided with renal transplants?
Sevoflurane –> Compound A
What paralytics are best to use with renal transplants?
Cisatracurium and Atracurium (Hofman Elimination)
What interventions can be done to maximize renal blood flow at time of graft reperfusion?
Blood volume expansion
Mannitol
Furosemide
What type of intervention is necessary for large stones that will not pass beyond the renal pelvis?
Percutaneous Lithotripsy
Wat position are patients placed in for a percutaneous lithotripsy?
Prone and the bed may be moved 180 degrees
What is a potential injury that can occur from a percutaneous lithotripsy?
Kidney injury from high pressure fluid delivery for nephroscope
What kind of technology is used to break the stone in a percutaneous lithotripsy?
Ultrasonic probe
What position is the patient in for a laser lithotripsy?
Lithotomy
What type of stones is a laser lithotripsy useful for?
Smaller stones
What is ectracorporeal shock wave lithotripsy?
High energy shock waves disrupt kidney stones
What type of stone are resistant to ESWL?
Calcium oxalate monohydrate
Calcium Phosphate
Cystine Calculi
What stones is the ESWL procedure best?
Stones in the renal pelvis or upper two thirds of ureters
What are common elements of all lithotriotors?
Ability to localize stone target
Generation of acoustical shock waves
MEchanism for focusing shock waves onto target stone
Technique for coupling shock wave generator to the patient
What is the goal of ESWL?
Pulverize calculi to allow urinary excretion over following weeks
Why is the timing of the ESWL shock wave so important?
Synchronized 20ms after R wave which corresponds to ventricular refractory period, prevents Vfib
About how many shock treatments are required for ESWL?
1000-4000 shocks
What are absolute contradictions to ESWL treatment?
Pregnancy, coagulopathy, intra-abdominal calcific process (AAA), orthopedic implants in lumbar/pelvic area
If a patient has a SB heart rhythm why might a provider give atropine or glycopyrolate to a patient receiving ESWL?
To speed the HR in order expedite the process
What are relative contraindications to ESWL?
Morbid obesity and pacemakers/AICDs
What do first generation lithotripters require to function?
Immersion in water bath serves as acoustic coupling substance
How does a second generation lithotripters function?
Membrane over shock wave generator allows patient to remain dry
What are the benefits of a third generation lithotripter?
Smaller, lighter, enhanced focal point
Multifunctional devices for urinary tract and biliary tract
If general anesthesia is used for lithotripsy how should the vent setting be adjusted?
Small TV to minimize stone displacement
What type of anesthesia is preferred for immersion type lithotriptors?
Regional
What level block is required for lithotripsy?
T4-6
What is a major disadvantage of regional anesthesia with lithotripsy procedures?
Inability to control diaphragmatic movement, can displace stone in excess of 12mm
What type of stone removal procedure has a high incidence of dysrhythmias?
ESWL
PAC and PVS most frequently noted
If emersion techniques are used what precautions should be taken so that accurate VS are obtained?
Cover EKG pads with water proof dressing
Clip B/P cuffs
Pulse ox on ear or nose
What is a common reason for a orchipexy in pediatric patients?
Undescended testicle
What type of regional anesthesia could be used for an orchioplexy?
Ilioinguinal nerve block
