Deutsch, S - ASA Refresher course in Anaesthetics - 1992; New
Orleans (Peer reviewed)
Surgical and anaesthetic considerations in TURP - Hatch, PD. - AIC (1987),15,203-211.
Melbourne short course notes - July 1993.
Bladder and prostate
Scrotal and testicular operations require sensory levels >= T10 - L2.
ANAESTHESIA FOR TURP
60-90% regionals +/- IV supplementation.
Advantages of regional
(i) less blood loss, fewer transfusions;
(ii) reduced incidence DVT/PE;
(iii) no evidence for fewer pulmonary complications;
(iv) reduction in stress response and ? less immune suppression - signif. unknown;
(v) allows assessment intraop for TURP syndrome;
GA - SV vs IPPV -> better CO2 control -> less bleeding.
Regional - PDPH low incidence using 25g or Sprotte needle - 0.02-0.4% Hyperbaric bupivacaine, sitting for 1 minute -> minimises splanchnic blockade with adequate cephalad spread.
Capsular sign - capsular tear -> T10-L2 pain with exposure of venous sinuses, increased irrigant absorption and risk of TURP syndrome. Traditionally block kept below T10 to preserve capsular sign, but this risks higher incidence of unsatisfactory blocks. Onus is on surgeon to keep observing for large capsular tears which may require retroperitoneal drainage and termination of procedure.
1. ANAESTHESIA RELATED
Minimised by careful monitoring and early intervention.
2. PROCEDURE RELATED
Circulating volume - related to XS absorption due to -
hyponatraemia, glycine toxicity and frank pulmonary
oedema/volume overload, haemolysis.
High percentage of patients with prostate disease have intercurrent CVS disease & tolerate fluid loads poorly.
TURP REACTION SYNDROME
Constellation of inter-related causes:
(i) dilutional hyponatraemia -> hypo-osmolality syndrome,
(ii) acute water intoxication (if H2O used),
(iii) glycine (including metabolite) toxicity.
Classical signs due to:
cerebral oedema - CNS signs/symptoms;
volume overload - HT, bradycardia, dyspnoea, LVF and CVS collapse;
low [Na+] - ECG changes - QRS prolongation, T inversion.
Incidence of severe hyponatraemia:
6% -> no change [Na+];
70% -> - 8 mmol.l-1 ch. in [Na+];
4% -> - 21 mmol.l-1 ch. in [Na+].
[Na+] < 120 mmol.l-1 generally required
before symptoms develop.
Rate of decrease more important - ie >= 20-30 mmol during case.
Easily diagnosed in regional anaesthesia, difficult in GA.
Progressive increase in BP is early sign of fluid overload.
(b) Glycine toxicity
- 2.4% isotonic,
- 1.5% is minimum non-haemolysing conc'n -> sl. hypotonic.
Clinical features - related to glycine's role as
inhibitory neurotransmitter in CNS, can be difficult to distinguish
from low [Na+]. Each abnormality may affect different
Nausea, malaise, vomiting, mild confusion, stupor and coma, severe disorientation and transient blindness correlated with the amount of glycine absorbed.
Irrigant < 1 litre, symptoms unlikely - 1.5 - 2.0 l absorbed irrigant toxicity likely.
Glycine metabolism results in amino acids - oxalate, proline, alanine and aminobutyrate and ammonia which may have a role in glycine toxicity.
NB 1.5 litres 1.5% gly. reduces [Na] - 140 -> 127 mmol.l-1, & osmo. - 290 -> 282.
- prevention best!!!
- inform surgeon immediately, check bag height;
- check [Na+] & osmolality urgently;
- loop diuretic, (NB will promote further Na+ losses, but water > Na+);
- fluid restriction, avoidance D5%W;
- supplemental O2;
- hypertonic (3%) Na+ 100 ml over 30 minutes for severe CNS or CVS symptoms, rapid [Na+] correction results in central pontine myelinolysis with permanent brain damage.
Total correction to normonatraemia not indicated - aim for clinical improvement and [Na+] >= 125 mmol.l-1.
NB - 3% NaCl = 513 mmol.l-1, 5% NaCl = 855 mmol.l-1.
Mannitol - possible indication, but increases risk of overload.
Risks - CPM, fluid overload \ CVP monitoring
indicated if hypertonic saline used.
Due to hypotonic irrigant -> RBC haemolysis -> haemoglobinaemia, haemoglobinuria and anaemia.
Chills, loin pain, pigmenturia, increased BP, bradycardia.
Renal afferent arteriolar constriction due to free Hb -> ATN, esp. if anaemia and further CVS decompensation occurs.
Management - adequate filling presures, osmotic
diuretics, low dose DA infusion.
(d) Circulatory overload
Increases bleeding due to raised venous pressure.
Changes in central volume with changes in position ie into and out of lithotomy -> ~ 800 ml sequestered in lower extremity in classical lithotomy position, less in "modified" lithotomy position ie legs at 45deg..
Irrigant absorption - 15-30 ml.min-1 operating time.
Assessment - pre and postop weight easiest.
Strategies to minimise:
(i) hydrostatic bag pressure <= 50-60 cmH2O - > 70 cmH2O = 2-fold increased absorption;
(ii) short operating time - < 60-90 minutes;
(iii) minimise intra-vesical pressure -> frequent emptying;
(iv) adequate haemostasis.
- difficult to quantify,
- measurement of the irrigant is most effective,
- communication between surgeon and anaesthetist most important
(i) radioactive RBC/albumin labelling,
(ii) changes in electrical conductivity of irrigant,
(iii) colorimetric methods - Hb estimation of sample of all irrigant used during the case:
Blood loss = Hb (irrigant) g.l-1x vol.(irrigant) ml
/ Hb(patient) g.l-1
Guessing blood loss will result in over-transfusing.
Average blood loss for TURP ~ 4-500 ml irrespective of anaesthetic.
Open prostatectomy - average 1050 ml; GA results in TWICE the transfusion rate as regional.
Type of anaesthesia makes little difference in TURP -> ~ 2.6-4.6 ml.min-1 blood loss whatever technique used.
Infection increases bleeding, cooled irrigant may decrease bleeding -> hypothermia.
XS bleeding due to local plasminogen activation by urinary urokinase -> systemic fibrinolysis in < 1% cases. More common with malignancy.
E-ACA -> plasminogen inhibitor. Theoretical risk of increased systemic thrombosis. Dose - 1 g.hour-1 for 24 hours.
Bleeding increased by
- large gland,
- malignancy -> smaller gland, quicker operation,
- open vs closed,
- duration of surgery - > 60-90 min -> dramatic increase,
- venous pressure,
- attention to haemostasis,
- elderly patients, cool irrigant, exposure lower limbs, water spilt on perineum.
- (1% TURPs) - urethral, intraperitoneal, extraperitoneal or
capsular with peri-prostatic extravasation -> 2deg. to
over-distension or instrumentation;
- abdominal, suprapubic and/or shoulder tip pain may indicate intraperitoneal extravasation (if sensory block below T10) -> "shock" like picture can develop if severe.
- spinal will not always prevent.
- gram negatives from infected urinary tract -> blood cultures is rigors, fever, hypotension. Treat if any evidence of gram neg. septicaemia.
(j) Electrical hazards
- skin burns if ground plate incorrectly placed.
- pacemaker interference possible.
(k) Adductor spasm
- due to stimulation of obturator nerve as it passes lateral to bladder neck - can block if problematical.
Incidence DVT - TURP ~ 6-10%; open - 24-47%.
Morbidity - 0.2%, mortality <0.1%.
TURP - less venous stasis, less pain & earlier mobilisation, less local trauma.
Prophylaxis - depends on number of risk factors -
age, intercurrent illness, previous DVT, malignancy, obesity,
immobility, low CO states, VVs.
- options - TEDs, SC heparin (LMWH), calf stimulators and compressors, dextrans, regional anaesthetic.
ANAESTHETIC CONSIDERATIONS - TURP
- adequate analgesia;
- minimal physiological disturbance;
- no compromise of compensatory mechanisms;
- adequate muscle relaxation;
- minimise drug doses, minimal blood losses;
- permit early recognition of complications.
Method of choice. Requires minimal anaesthetic with minimal physiological insult and low incidence of PDPH. Resp. function preserved, and volume preload prevents severe hypotension.
Require block from -
(i) T10 - L3 - Sic via sup. hypogastric plexus -> motor to bladder incl. internal sphincter, sensation to trigone;
(ii) S2-4 - Psic via pelvic splanchnics -> motor to sphincter urethrae, sensation to glans, urethra and perineum.
Drugs - (a) heavy lignocaine 5% - 3-4 ml (150-200
(b) isobaric 0.5% bupiv. - 2-4 ml (10-20 mg);
(c) heavy bupiv. 0.5% - 2-4 ml.
Long duration advantageous - pain free recovery with decreased analgesia requirements.
If regional C/I - GA using controlled or spontaneous breathing.
Relaxant technique -> better CO2 control, with less bleeding possibly.
Preop. - treat infection, full assessment and
optimisation of medical condition.
High proportions of intercurrent disease, eg., DM, CAD, CAL, CNS, vascular. Regional anaesthesia well tolerated, and not associated with a significant increase in perioperative cardiac morbidity.
Monitoring - HR, BP, SpO2, ECG, pigmenturia, conscious level if regional, RR using capnography in sedated patients and/or those with chronic lung disease.
- increased blood loss regional vs GA,
- epidural associated with a decrease in the incidence of DVT.
- + loop ileostomy -> long operation with significant
- GA/epidural combination used with success; reduced incidence of DVT/PE.
SURGERY FOR NEPHROLITHIASIS
1. EXTRACORPOREAL SHOCK-WAVE LITHOTRIPSY
Most common non-invasive remedy for nephrolithiasis - stones >
20mm -> too many fragments \ limited to stones < 20mm
Biplanar fluoroscopy to apply shock waves to the flank, focusing on the target stone.
Several thousand shocks per treatment -> stone disintegrates.
- blistering of the skin where the shock wave enters,
- renal oedema and haemorrhage into the renal pelves.
Outpatient basis usually.
VT or VF during the vulnerable period of the cardiac cycle during early development of the technique .
Shock waves now linked to the R-wave.
Ventilation causes the stone to move, \ heart-synchronised ventilation overcomes ECG and movement problems.
High frequency jet ventilation also used to overcome stone movement.
No differences in morbidity GA vs regional - ie GA with HFJV vs regional with low volume respiration.
EDB to T4 - T6 required.
Monitoring includes SpO2; NB ear protection.
Modern 2nd generation lithotripters generate shocks through a moistened gel interface, avoiding immersion in water bath with minimal circulatory side effects, less pain due to lower power and finer focus.
all types and ages.
GA may be best technique in terms of - simplicity, speed, patient comfort - hard table, uncomfortable position and variable length.
Spinals associated with high incidence of PDPH - 45% - reduced to 8% using prophylactic blood patch.
Sedation possible, but large narcotic requirement with concern about airway adequacy.
O2 supplementation in all cases.
Pharmacological manipulation of HR - shock synchronised
with ECG (R wave). Higher HR decrease duration of procedure but rates
greater than 130/min result in lithotripter reverting to half
Newer machines deliver double shock.
2. PERCUTANEOUS NEPHROLITHIASIS.
For stones not amenable to ESWL.
All patients, ASA I-III, generally healthier than average urology patients.
Epidural is effective for placement of nephrostomy tube under I-I control, and destroying the stone in the OR.
GA preferable -> lithotomy to prone position.
Prone position - bolster under chest and pelvis -> abdo
excursion during inspiration.
BUT in this procedure - prone decubitus position with bolster under one side of the abdomen (operated side) to reduce the parenchymal distance from surface to renal tract, avoiding renal vessels.
In practice respiratory compromise seldom seen.
IVC obstruction possible but uncommon since bolster is unilateral.
IV - same side as operation -> arm is abducted.
(a) retroperitoneal fluid extravasation if renal pelvis perforated;
(b) bleeding - 6% cases require transfusion -> occasionally need open haemostasis;
(c) absorption of N/S irrigant from retroperitoneal space in prolonged cases;
(d) thermal control;
(e) sepsis - 6% \ antibiotics routine;
(f) ileus - 2deg. to retroperitoneal fluid (brief duration);
(g) pain - 50% need narcotics in first 24 hours; ketorolac OK for short-term use;
(h) potential for pneumothorax.
OPERATIONS ON THE KIDNEY INCLUDING TRANSPLANTATION.
Major problems in patients with renal disease -
(i) HT and cardiac failure,
(v) Increased susceptibility to infection.
Lateral decubitus position common with kidney rest.
Hypotension is common - due to
- compression of the great vessels,
- pooling in the extremities,
- decreased VR from the upper body.
Careful volume loading and gentle positioning minimises the BP fall.
ESRF not a major problem provided electrolytes near normal range,
minimal coag. abnormalities, and drug metabolism accounted for -
abnormal Pb, changes in Vd, decreased renal elimination of muscle
relaxants and opioids in particular.
Steroid cover often indicated.
- [K+], ECG, CXR,
- coagulation studies,
- Hb, X-match,
- steroids/immunosuppressants yes or no,
- when was last dialysis,
- A-V fistula or shunt location -> avoid IV placement.
- clinical monitoring - colour, perfusion, mental state (in regional),
- CVP often indicated to avoid fluid overload,
- ECG, SpO2, capnography, PNS, temp, blood loss, HCT, arterial line indicated if severe preop HT, large volume changes anticipated or if BP maintenance critical,
- urinary catheter.
- atracurium , vecuronium best relaxants to use,
- morphine and its metabolites renally excreted, \ prolonged t1/2,
- avoid ketorolac.
Complex urological cases are often long duration with potential for large blood losses and transfusion requirements eg - renal tumour resection and LN clearance with extensive dissection;
- cystectomy and conduit reconstruction - 4-6 hours.
(i) Thermal control - ambient temp. increase,
- warm IV fluids - coils and warmers,
- warming blankets/Bair hugger,
- wrap exposed parts, limit evaporative losses -> bowel bag,
- warm and humidify inspired gases -> Fisher and Paykel humidifier.
(ii) Pressure points and nerve protection - wrap heels and check periodically,
- brachial plexus at risk with both arms abducted \ abduction < 90deg. with arms in pronation.
(iii) DVT prophylaxis - calf-compressors, SC heparin, calf stimulators, TED stockings,
regional -> reduces incidence of DVT effectively.
(iv) Blood loss - fluid requirements always greater than anticipated - 2-4 litres positive often.
- NB Head-down position -> significant upper airway oedema possible \ caution before extubation.
- losses associated with bowel exposure - ~ 10-20 ml.kg.-1hr-1.
- massive transfusion sometimes -> involve haematologist early if anticipated, monitor clotting and HCT, FFP, platelet replacement if indicated.
TURP - G & H only if consultant surgeon;
- 2 units if registrar;
Open prostatectomy - 2 units X-matched;
Cystectomy - 4 units X-matched;
Nephrectomy with IVC dissection - 6 units minimum.
(v) Technique - ED/GA combination advantageous:-
(a) reduction of blood losses;
(b) greater haemodynamic stability;
(c) DVT risk reduced;
(d) analgesia into postoperative period;
(e) lower concentrations GA agents -> rapid awakening and earlier extubation.