ANAESTHETIC MANAGEMENT OF ENDOSCOPIC UROLOGIC PROCEDURES DR. RICHA JAIN
Transcription
ANAESTHETIC MANAGEMENT OF ENDOSCOPIC UROLOGIC PROCEDURES DR. RICHA JAIN
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. PAIN CONDUCTION PATHWAYS ORGAN SYMPATHETIC PARASYMPATHETIC SPINAL LEVEL OF PAIN CONDUCTION KIDNEY T8 – L1 CN X (VAGUS) T10 – L1 URETER T10 – L2 S2 – S4 T10 – L2 BLADDER T11 – L2 S2 – S4 T11 – L2(DOME) S2 – S4(NECK) PROSTATE T11 – L2 S2 – S4 S2 – S4 PENIS S2 – S4 S2 – S4 L1, L2 CYSTOSCOPY 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 procedure and patient preference General anesthesia - children. Topical anesthesia with or without sedation – diagnostic studies. Regional or general anesthesia – operative cystoscopies. TRANSURETHRAL RESECTION OF BLADDER TUMOUR (TURBT) TURBT For diagnosing and treating bladder cancers PROCEDURE o o o o o 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. ANAESTHETIC CONSIDERSTIONS 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. TRANSURETHRAL RESECTION OF PROSTATE (TURP) 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 85year-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 hypogastric plexus BLOOD SUPPLY 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 threelumen catheter is inserted and irrigation is continued for up to 24 h after operation. The procedure usually takes 30–90 min. IRRIGATION FLUIDS Uses distends bladder and prostatic urethra flushes out blood and tissue debris improves visibility Characteristics of Ideal irrigation fluid: 1. 2. 3. 4. 5. 6. 7. 8. 9. Transparent Isotonic Electrically inert Non hemolytic Inexpensive Not metabolizable Rapidly excretable Non toxic Easy to sterilise SOLUTION OSMOLALITY ADVANTAGES (mOsm/kg) DISADVANTAGES DISTILLED WATER 0 (hypo) Electrically inert Improved visibility Inexpensive Hemolysis Hemoglobinuria Hemoglobinemia Hyponatremia GLYCINE (1.5%) GLYCINE (1.2%) 220 (iso) Less likelihood of Transient TURP syndrome postoperative visual syndrome, Hyperammonemia, Hyperoxaluria NORMAL SALINE (0.9%) 308 (iso) RINGER LACTATE 273 (iso) 175 (hypo) Less incidence of TURP syndrome Ionized, cannot be used with cautery Ionized, cannot be used with cautery SOLUTION OSMOLALITY (mOsm/kg) ADVANTAGES DISADVANTAGES MANNITOL (5%) 275 (iso) Isomolar Osmotic diuresis, solution Acute intravascular Not metabolized expansion SORBITOL (3.5%) 165 (hypo) GLUCOSE (2.5%) 139 (hypo) Hyperglycemia UREA (1%) 167 (hypo) Increases blood urea CYTAL (sorbitol 2.7% +mannitol 0.54%) 178 (iso) Expensive, not easily available Same as glycine Hyperglycemia, Lactic acidosis Osmotic diuresis 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. 2. 3. 4. 5. 6. 7. 8. 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 MECHANISM OF TURP SYNDROME TURP SYNDROME – WATER INTOXICATION Cause : cerebral edema Signs and symp: Somnolence, restlessness, seizures, coma CNS – decerebrate posture, clonus, +ve babinski’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 Confusion Restlessness Hypotension bradycardia wide QRS complex 115 Somnolence Nausea Cardiac depression Bradycardia Wide QRS complex Elevated ST segment 110 Seizures Coma CHF Ventricular tachycardia 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 hrs and 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 hypoosmolality Hyperglycinemia Hyperammonemia Cardiovascular Hypertension, reflex bradycardia, Rapid fluid absorption pulmonary edema, CVS collapse Hypotension Third spacing ECG changes(wide QRS, elevated Hyponatremia ST segments, vent arrhythmia) 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. 2. 3. 4. 5. 6. 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 preop Hb, 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 AND NEPHROLITHOTRIPSY (PCNL) 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. ANATOMICAL CONSIDERATIONS Kidneys are retroperitoneal organs, located in paravertebral gutters. Right kidney lies adjacent to 12th rib, liver, duodenum and hepatic flexure of colon. Left kidney is related to 11th and 12th ribs, stomach, pancreas, spleen and splenic flexure of colon. Superior pole in direct contact with diaphragm. PCNL : PROCEDURE PCNL consists of gaining percutaneous access to the kidney collecting system and performing stone disintegration, usually with ultrasonic or pneumatic lithotripters. PERCUTANEOUS APPROACHES Subcostal /Intercostal approach Intercostal puncture is made over lateral portion of rib but medial to viscera during expiration A hollow needle placed into the renal collecting system under fluoroscopy A guide wire inserted through the needle and Dilators passed over the wire After tract dilation, a working sheath is left in place Nephroscope inserted to directly visualize stone Small stone grasped under direct vision Larger stones fragmented by ultrasound or electrohydraulic probe A nephrostomy tube is left to drain the system INTRAOPERATIVE COMPLICATIONS HAEMORRHAGE INJURY TO RENAL PELVIS FLUID ABSORPTION INJURY TO PLEURA INJURY TO ADJACENT ORGANS SEPTICEMIA ANAESTHETIC TECHNIQUE PCNL can be performed under general or regional anesthesia. General anesthesia is preferred. Patient is laid in prone/ lateral oblique position. ANAESTHETIC CONSIDERATIONS POSITION - Prone / lateral oblique position INTRATHORACIC COMPLICATIONS • • Most often injured organ during PCNL : lung and pleura. Risk of injury increases with more superior punctures. Approach Incidence Subcostal 0.5% Supra-12th rib 1.5 – 12% Supra – 11th rib 23.1% ANAESTHETIC CONSIDERATIONS Close coordination of percutaneous access puncture and tract dilation with respiration is essential to minimise pleural injury. • Monitoring of airway pressure, ETCO2 , SpO2 required. • Fluoroscopic monitoring of chest during procedure is a sensitive means of timely diagnosis of pneumothorax or hydrothorax. • A chest X-Ray recommended in the recovery room. • ANAESTHETIC CONSIDERATIONS Acute anemia due to blood loss or hemodilution . Repeat Hb measurement should be considered in the perioperative period. Fluid absorption due to high pressure fluid irrigation in presence of venous injury or collecting system perforation. Can lead to hypothermia, TURP syndrome, sepsis. ANAESTHETIC CONSIDERATIONS Hypothermia due to large amount of fluids administered for irrigation. Causes shivering, peripheral vasoconstriction and delayed drug clearance. Prevention by use of warmed intravenous and irrigation fluids. Septicemia All patients have urine cultures done preoperatively with administration of an appropriate antibiotic 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. Vsevold Rozentsveig. Anesthetic considerations during percutaneus nephrolithotomy. Journal of Clinical Anesthesia 2007:19,351-355. Dietrich Gravenstein. Transurethral resection of prostate (TURP) syndrome: a review of pathophysiology and management. Anesth Analg 1997;84:438-46. . 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