ANAESTHETIC MANAGEMENT OF ENDOSCOPIC UROLOGIC PROCEDURES DR. RICHA JAIN University College of Medical Science & GTB Hospital, Delhi
ENDOSCOPIC UROLOGIC PROCEDURES • Endoscopic urologic procedures are performed on kidneys, ureters, urinary bladder, prostate, urethra. • CYSTOSCOPY • URETEROSCOPY • TRANSURETHRAL RESECTION OF BLADDER TUMOUR (TURBT) • TRANSURETHRAL RESECTION OF PROSTATE (TURP) • PERCUTANEOUS NEPHROLITHOTRIPSY ( PCNL)
ANATOMIC CONSIDERATIONS • The sensory nerve supply to genitourinary organs is primarily thoracolumbar and sacral outflow thus, well adapted for regional anesthesia.
CYSTOSCOPY • The most common urologic procedure • Indications • Diagnostic • Hematuria • Recurrent urinary infections • Urinary obstruction • Bladder biopsies • Retrograde pyelograms • Therapeutic • Resection of bladder tumors, • Extraction or laser lithotripsy of renal stones, • Placement or manipulation of ureteral catheters (stents) .
Anaesthetic management • Varies with age, the indication of the procedureandpatient preference • General anesthesia - children. • Topical anesthesia with or without sedation – diagnostic studies. • Regional or general anesthesia – operative cystoscopies.
TURBT • For diagnosing and treating bladder cancers • PROCEDURE • Patient laid in lithotomy position. • Cystoscope or resectoscope is introduced into the bladder. • The tumor is identified & resected. • Coagulating current is used to cauterize the base of the tumor. • Typical duration of procedure: around 1 h.
Anaestheticconsiderstions • Preoperative Considerations • Bladder tumor is usually seen in older populations who may have pre-existing medical problems. • Pt may have hematuria, urinary infection. • Intraoperative Concerns • Lithotomy positioning • Bladder perforation. • Bleeding. • Obturator reflex. • Stimulation of the obturator nerve by electrocautery may cause the thigh muscles to contract violently, leading to bladder perforation. • This reflex may be eliminated by blocking neuromuscular transmission using a muscle relaxant during GA or by obturator nerve block.
TURBT – CHOICE OF ANAESTHESIA • Anaesthetic technique – regional or general anesthesia. • Neuraxial regional block preferred. • Anaesthetic level to T10 is required. • GA is indicated when patient requires ventilatory or haemodynamic support.
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 fibromuscularstroma. • 2 capsules: • True – formed by condensation of prostatic tissue • False – formed by visceral layers of pelvic fascia.
NERVE SUPPLY BLOOD SUPPLY ANATOMY OF PROSTATE • Sympathetic supply • T11-L2 • Inferior hypogastric plexus • Parasympathetic supply • S2,3,4 • Pelvic splanchnic nerve • Arterial supply • Inferior vesical artery • Middle rectal artery • Internal pudendal artery • Venous supply • Vesical plexus • Internal pudendal veins • Vertebral venous plexus
TURP - PROCEDURE • 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.
IRRIGATION FLUIDS • Characteristics of Ideal irrigation fluid: • Transparent • Isotonic • Electrically inert • Non hemolytic • Inexpensive • Not metabolizable • Rapidly excretable • Non toxic • Easy to sterilise • Uses • distends bladder and prostatic urethra • flushes out blood and tissue debris • improves visibility
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 • Allows monitoring of mentation and early signs of TURP syndrome and bladder perforation • Promotes peripheral vasodilation , reducing circulatory overload • Reduces blood loss, requiring fewer transfusions • Avoids effects of general anaesthesia on pulmonary pathology • Good early post-operative analgesia • Reduced incidence of post-operative DVT/PE • Neuroendocrine and immune response are better preserved • 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 Main challenges: blood loss and TURP syndrome
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
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
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 glycinetoxcity: 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 hrs and awakens when blood NH3 < 150 mmol/L. • Explanation : arginine deficiency
MEASUREMENT OF FLUID ABSORPTON • Volume absorbed = (preoperative Na+/ postoperative Na+ ) ECF - ECF • Volumetric fluid balance (diff. b/w amt of irrigation fluid used and volume recovered.) • Gravimetry (measure rise in body weight) • CVP monitoring • Breath ethanol measurement • 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 preopHb, duration and difficulty of resection and clinical assessment of pt condition.
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
PERCUTANEOUS NEPHROLITHOTOMY • The procedure of choice for removing complex and large renal stones. • Imp. Indications of PCNL : • Stone size >/= 2.5 cm. • Stones resistant to ESWL • Staghorn stones in lower calyx • Advantages of percutaneous method • Lower morbidity and mortality • Faster convalescence • Small incision • Minimum operative and postoperative complications.