Anaesthetic managent of turp

ANAESTHETIC MANAGENT OF TURP Presentor : Ritika Gupta

Moderator : Dr Trishala Jain

TURP - INTRODUCTION

The current gold standard surgical treatment for benign prostatic hyperplasia (BPH).

TURP is the 2nd most common procedure in men over 65 yrs of age.

BPH affects 50% of males at 60 years and 90% of 85-year-olds, so TURP is most commonly performed on elderly patients, a population group with a high incidence of cardiac, respiratory and renal disease.

TURP carries unique complications because of the need to use large volumes of irrigating fluid for the endoscopic resection.

ANATOMY OF PROSTATE LOCATION: in the pelvis, below neck of

urinary bladder

SHAPE : inverted cone

SIZE : 4x3x2 cm

Weight : 8 gm

5 LOBES:

BPH – median, anterior, 2 lateral

Prostatic carcinoma – posterior, lateral

Composed of glandular tissue in fibromuscular stroma.

2 capsules:

True – formed by condensation of prostatic tissue

False – formed by visceral layers of pelvic fascia.

ANATOMY OF PROSTATE

NERVE SUPPLY

Sympathetic supply

T11-L2

Inferior hypogastricplexus

Parasympathetic supply

S2,3,4

Pelvic splanchnic nerve

BLOOD SUPPLY

Arterial supply

Inferior vesical artery

Middle rectal artery

Internal pudendal artery

Venous supply

Vesical plexus

Internal pudendal veins

Vertebral venous plexus

Performed in the lithotomy position using a resectoscope, through which a diathermy loop is passed.

The prostatic tissue is resected in small strips under direct vision using the diathermy loop.

The bladder is continuously irrigated with fluid.

At end of the procedure, a three-lumen catheter is inserted and irrigation is continued for up to 24 h after operation.

The procedure usually takes 30–90 min.

TURP - PROCEDURE

IRRIGATION FLUIDS

Uses

distends bladder and prostatic urethra

flushes out blood and tissue debris

improves visibility

Characteristics of Ideal irrigation fluid:

1. Transparent

2. Isotonic

3. Electrically inert

4. Non hemolytic

5. Inexpensive

6. Not metabolizable

7. Rapidly excretable

8. Non toxic

9. Easy to sterilise

SOLUTION OSMOLALITY (mOsm/kg)

ADVANTAGES DISADVANTAGES

MANNITOL(5%)

275 (iso) IsomolarsolutionNotmetabolized

Osmotic diuresis, Acute intravascular expansion

SORBITOL(3.5%)

165 (hypo) Same as glycine

Hyperglycemia,Lactic acidosisOsmotic diuresis

GLUCOSE(2.5%)

139 (hypo) Hyperglycemia

UREA(1%)

167 (hypo) Increases blood urea

CYTAL(sorbitol2.7% +mannitol0.54%)

178 (iso) Expensive, not easily available

SOLUTION OSMOLALITY (mOsm/kg)

ADVANTAGES DISADVANTAGES

DISTILLED WATER

0 (hypo) Electrically inertImprovedvisibilityInexpensive

HemolysisHemoglobinuriaHemoglobinemiaHyponatremia

GLYCINE (1.5%) GLYCINE(1.2%)

220 (iso)

175 (hypo)

Less likelihood of TURP syndrome

Transientpostoperative visual syndrome,Hyperammonemia,Hyperoxaluria

NORMAL SALINE (0.9%)

308 (iso) Less incidence of TURP syndrome

Ionized, cannot be used with cautery

RINGER LACTATE

273 (iso) Ionized, cannot be used with cautery

Factors affecting amount and rate of fluid absorption

Size of gland (25ml/gm of prostate)

Number and size of open sinuses

Hydrostatic pressure of irrigating fluid

Duration of procedure (@ 20-30 ml/min)

Integrity of capsule

Venous pressure at irrigant-blood interface

Vascularity of diseased prostate

PREOPERATIVE CONSIDERATIONS Patients for TURP are frequently elderly with coexistent diseases.

- cardiac disease 67%

- cardiovascular disease 50%

- abnormal electrocardiogram (ECG) 77%

- chronic obstructive pulmonary disease 29%

- diabetes mellitus 8%

Occasionally, patients are dehydrated and depleted of essential electrolytes (long-term diuretic therapy and restricted fluid intake).

Long standing urinary obstruction can lead to impaired renal function and chronic urinary infection.

About 30% of TURP patients have infected urine preoperatively

PREOPERATIVE EVALUATION

History and examination of all organ systems

INVESTIGATIONS

Hb, TLC, DLC, platelet count

Blood sugar

Blood urea, S. Creatinine, S. Electrolytes

Urine R/M

ECG

Chest X-ray

Blood grouping and cross matching

PREOPERATIVE PREPARATION

Optimization of pre-existing co-morbid conditions

Consideration of ongoing drug therapy

Antibiotic prophylaxis (in case of urinary tract infection or urinary obstruction)

Arrangement of blood

CHOICE OF ANAESTHESIA Regional anaesthesia is the technique of choice for TURP.

Advantages of regional over general anaesthesia

1. Allows monitoring of mentation and early signs of TURP syndrome and bladder perforation

2. Promotes peripheral vasodilation , reducing circulatory overload

3. Reduces blood loss, requiring fewer transfusions

4. Avoids effects of general anaesthesia on pulmonary pathology

5. Good early post-operative analgesia

6. Reduced incidence of post-operative DVT/PE

7. Neuroendocrine and immune response are better preserved

8. Lower cost

General anaesthesia preferred when regional is contraindicated.

REGIONAL ANAESTHESIA

TECHNIQUES:

Subarachnoid block

Epidural block

Caudal block

Saddle block

Level of sensory block

T10 dermatome level – to eliminate discomfort caused by bladder distention

T9 dermatome level – enable to elicit capsular sign (pain on perforation of prostatic capsule)

REGIONAL ANAESTHESIA

Subarachnoid block is preferred.

Advantages of SAB over epidural anaesthesia:

Technically easier to perform

Dense motor blockade

No sacral sparing

Lower incidence of PDPH

MONITORING

ECG

Blood pressure

Pulse oximetry

Temperature

Mentation

Blood loss

S. electrolytes (serial)

EtCO2 if GA is used

INTRAOPERATIVE CONSIDERATIONS

Lithotomy position

TURP syndrome

Bladder perforation

Hypothermia

Transient bacterial septicemia

Hemorrhage and coagulopathy

LITHOTOMY POSITIONING

Both lower limbs raised together, flexing the hips and knees simultaneously.

Ensure proper padding at edges and angulations.

While lowering, legs brought together at knees and then lowered slowly to prevent stress on spine and sudden fall in BP.

LITHOTOMY POSITIONING

Physiologic changes with lithotomy

Decreased FRC

Increased venous return on elevation of legs

Decreased venous return following lowering of legs

Exaggeration of hypotension with SAB

Problems with lithotomy position

Injury to nerves

Injury to fingers

Compression of major vessels at joints

Lower extremity Compartment syndrome

Aggravation of preexisting lower back pain

TURP SYNDROME Rapid absorption of a large-volume irrigation solution.

Can occur 15 min after resection or upto 24 hrs postop.

Incidence : 1 – 8%

Characterized by intravascular volume shifts and plasma-solute (osmolarity) effects:

Circulatory overload

Water intoxication

Hyponatremia

Hypoosmolality

Hyperglycinemia

Hyperammonemia

Hemolysis

MECHANISM OF TURP SYNDROME

TURP SYNDROME – WATER INTOXICATION Cause : cerebral edema

Signs and symp:

Somnolence, restlessness, seizures, coma

CNS – decerebrate posture, clonus, +vebabinski’s reflex

Eyes – papilloedema, dilated and non reactive pupils

EEG – low voltage b/l.

TURP SYNDROME -HYPONATREMIA Cause : excessive absorption of Na free irrigation

fluid

During TURP, S.Na falls by 3 to 10 meq/l.

SIGNS AND SYMPTOMS OF Acute Hyponatremia

Nausea

Vomiting

Irritability

Mental confusion

Cardiovascular collapse

Pulmonay edema

Seizures

Manifestations of hyponatremia

SERUM Na+

(mEq/l)CNS changes

CVS changes

ECG Changes

120 ConfusionRestlessness

Hypotension bradycardia

wide QRS complex

115 SomnolenceNausea

Cardiacdepression

BradycardiaWide QRS complexElevated ST segment

110 Seizures Coma

CHF Ventriculartachycardia or fibrillation

TURP SYNDROME -HYPERGLYCINEMIA

Glycine, a non essential amino acid, is an inhibitory neurotransmitter in spinal cord and retina.

Metabolized in liver by oxidative deamination to ammonia and glyoxylic and oxalic acid.

When absorbed in large amounts, has direct toxic effects on heart and retina.

Manifestations of glycine toxcity: nausea, headache, malaise, weakness, visual distubances ( transient blindness), seizures, encephalopathy.

TURP SYNDROME -HYPERAMMONEMIA

Excessive absorption of glycine may lead to hyperammonemia (blood NH3> 500mmol/L).

S/S: nausea, vomiting, comatose for 10-12 hrsand awakens when blood NH3 < 150 mmol/L.

Explanation : arginine deficiency

TURP SYNDROME – CLINICAL FEATURES System Signs and Symptoms Cause

Neurologic Nausea, restlessness, visual disturbances, confusion, somnolence, seizures,coma,death

Hyponatremia and hypoosmolalityHyperglycinemiaHyperammonemia

Cardiovascular Hypertension, reflex bradycardia, pulmonary edema, CVS collapseHypotension ECG changes(wide QRS, elevated ST segments, vent arrhythmia)

Rapid fluid absorption

Third spacingHyponatremia

Respiratory Tachypnea, oxygen desaturation, cheyne- stokes breathing

Pulmonary edema

Hematologic Disseminated intravascular hemolysis

Hyponatremia and hypoosmolality

Renal Renal failure Hypotension, hemolysis,hyperoxaluria

Metabolic Acidosis Deamination of glycine

MEASUREMENT OF FLUID ABSORPTON

1. Volume absorbed = (preoperative Na+/ postoperative Na+ ) ECF - ECF

2. Volumetric fluid balance (diff. b/w amt of irrigation fluid used and volume recovered.)

3. Gravimetry (measure rise in body weight)

4. CVP monitoring

5. Breath ethanol measurement

6. Isotopes

TURP SYNDROME - PREVENTION

Early diagnosis and prompt treatment

Correction of fluid and electrolyte abnormalities preoperatively

Cautious adminstration of IV fluids

Limitation of hydrostatic pressure of irrigation fluid to 60cm

Restrict duration of TURP to 1 hr

Bipolar resectoscope

Vaporization methods

Local vasoconstrictors

TURP SYNDROME -MANAGEMENT

Notify surgeon and terminate surgery.

Ensure oxygenation

Restrict fluids

Pulmonary edema : intubate and IPPV

Bradycardia, hypotension: atropine, adrenergic agents

Seizures : BZD, thiopentone, phenytoin, i.v.Mg2+

Invasive monitoring of arterial and CVP

Send blood sample for electrolytes, arterial blood gas analysis.

TURP SYNDROME -MANAGEMENT

Treat mild symptoms (if S. Na+ > 120 mEq/L) with fluid restriction and loop diuretic (furosemide)

Treat severe symptoms (if S. Na+ <120 mEq/L) with 3% NaCl IV at rate < 100 ml/ hr.

BLADDER PERFORATION

Incidence – 1%

Causes

Trauma by surgical instrument

Overdistention of bladder with irrigation fluid

Manifestation

Early sign : sudden decrease in return of irrigation solution from bladder

Extraperitoneal perforations : pain in periumbilical, inguinal or suprapubic region

Intraperitoneal : generalised abdominal pain, shoulder tip pain, abdo rigidity

BLOOD LOSS

Difficult to quantify blood loss.

Visual estimation of haemorrhage may be difficult due to dilution with irrigation fluid.

Usual warning signs (tachycardia, hypotension) masked by overhydration and effects of regional anaesthesia.

Blood loss can be estimated on the basis of

Resection time (2-5ml/min)

Size of prostate (7-20ml/g)

No. of open venous sinuses

Intraoperative BT should be based on preop Hb, duration and difficulty of resection and clinical assessment of ptcondition.

COAGULOPATHY

Causes of excessive bleeding

Dilutional thrombocytopenia

DIC as a result of release of prostatic particles rich in thromboplastin into blood

Local release of fibrinolytic agents (plasminogen and urokinase)

Treatment – administration of FFP, platelets blood transfusion

HYPOTHERMIA

Continuous fluid irrigation causes loss of temp @1oC/hr.

Elderly patients have reduced thermoregulatory capacity.

Unintentional hypothermia is asso. with a significantly higher incidence of postoperative MI.

Postoperative shivering asso. with hypothermia may dislodge clots and promote postoperative bleeding.

Monitor body temp of patient to maintain normothermia.

Appropriate measures to reduce heat loss are: warming blankets, heated irrigation solution and warm I/V fluids.

BACTEREMIA AND SEPTICEMIA

INCIDENCE – 6-7%

Causes

Release of bacteria from prostatic tissue

Preoperative indwelling urinary catheter

Preoperative UTI

C/F – chills, fever, tachycardia

T/T – antibiotic, supportive care

POSTOPERATIVE COMPLICATIONS

Hypothermia

Hypotension

Haemorrhage

Septicaemia

TURP syndrome

Bladder spasm

Clot retention

Deep vein thrombosis

Postoperative cognitive impairment

REFERENCES

Miller’s Anesthesia 7th Editon. Anesthesia and renal and genitourinary system.

Barasch’s Clinical Anesthesia 5th Edition. The renal system and anesthesia for urologic surgery.

Yao and Artusio’s Anesthesiology problem oriented patient management. 6th Edition.

Clinical anesthesiology by Morgan and Mikhail. 4th

Edition. Anesthesia for genitourinary surgery.

Dietrich Gravenstein. Transurethral resection of prostate (TURP) syndrome: a review of pathophysiology and management. Anesth Analg 1997;84:438-46.