anaesthetic choices for lithotripsy
TRANSCRIPT
Anaesthetic choices for lithotripsy
Dr Nida FatimaDepartment of Anaesthesia and Critical care, JN
Medical college and hospital AMU aligarh
Urolithiasis• Prevalence of stone disease -1% to 15%.• Varies- age, gender, race, and geographic
location.• stone formation - migrated -lower to the
upper urinary tract.• once limited to men is increasingly gender
blind.
UROLITHIASIS
Forced Diuresis
Alkalisation of urine
Tamsulosine with
hydration
Extra Corporeal
Shockwave Lithotripsy
Percutenous Nephro-lithopexy
Uretro-Reno scopic Lithotripsy
Cysto-litholapexy
Pyelo/Nephro/Cysto/
Urethro- lithotomy
NephrectomyIf non
functional kidney
Endoscopic removal
• Lithotripsy( Greek) meaning "stone crusher“.• Techniques:• Extracorporeal shock wave lithotripsy• Laser lithotripsy• Electro-hydraulic lithotripsy• Mechanical lithotripsy• Ultrasonic lithotripsy
What is lithotripsy?
• Introduction ESWL in 1980. • 85% of renal calculi - treated• Externally generated, harmlessly penetrated
shock waves, provide pressure (900-1000 bar) on a kidney stone to disintegrate it into smaller granules.
Why lithotripsy?
Extracorporeal shock wave lithotripsy (ESWL)
• Disintegration of urinary stones in the ureter and kidney.
• High-energy waves (20 kilovolts)- focused on ureter or kidney.
• Lithotripter uses “R-wave ECG”- trigger for shock wave - refractory period of the cardiac cycle.
When lithotripsy?
MANAGEMENT OF RENAL CALCULI by ESWL
< 2cm in diameter and/or surface area < 500 mm2
Treatment : ESWL mono-therapy
> 2cm in diameter and/or surface area > 500 mm2
Treatment : PCNL +/- ESWL Combination therapy
Lithotripter• Comprises of:• spark plug• Energy reflector• Energy concentrator• Fluoroscopy• ultrasound
Spark plug Energy vaporize water external shock wave water bath/cushions Release energy patient’s body
stone
generate
Focussed on
Passed to
hits
Crushed to pieces
- The sudden expansion of air bubbles created sets up a pressure wave (shock wave)
- Focused onto F2 focus
- Exponential reductionenergy of wave beyond F2.
EFFECTS OF RESPIRATION
• For shock waves -most effective- stone at F2 focus during treatment.
• Because of movements during respiration… The stone is likely to move in and out of focus.
• To increase the efficacy of the treatment :• decreased tidal volumes ,increased respiratory
rates, high-frequency jet ventilation .
Physiological effects of lithotripsy• Mechanical stimulation of myocardium and
conduction system…arrhythmias.• Atrial premature contraction• Ventricular premature contraction• Atrial fibrillation• Supraventricular tachycardia• Ventricular tachycardia
When a patient is placed in a water bath: Problems
• Cardiac preload is augmented• Increase in CVP and PCWP• Compression -peripheral venous system.• ↑ SV and cardiac output of 30%.• Hydrostatic pressure on the chest:
↓ FRC by 30% and VC by 20%.• ↓tidal volume , ↑ work of breathing
Changes on Immersion during Lithotripsy
Cardiovascular
Increased Central blood volume
Increased Central venous pressure
Increased Pulmonary artery pressure
Respiratory
Increased Pulmonary blood flow
Decreased Vital capacity
Decreased Functional residual capacity
Decreased Tidal volume
Increased Respiratory rate
• Newer lithotripters no need of water bath.• universal table for fluoroscopy.• energy can be focused more precisely.• less painful.
Renal changes
• Diuresis, natriuresis, and kaliuresis.• ↓ADH and renal prostaglandins
Temperature changes: • This heat transfer is augmented -vasodilation
produced by general or epidural anesthesia. • Hypothermia and hyperthermia have been
reported.
• The pathogenesis -multifactorial. • - Both cutenous and visceral nociceptors
Visceral nociceptors –• periosteal,• pleural,• peritoneal, • musculoskeletal pain receptors
PAIN
Variables associated with pain
• the type of lithotriptor, • size of focal zone• shockwave peak pressure,• size and site of stone burden• area of shockwave entry at the skin, • location of the shockwave front
Special considerations!!!
• Women of childbearing age need to undergo- a pregnancy test.• Abdominal aortic aneurysms with calcium deposits• orthopedic prostheses - kept out of the path of shock
wave.• Lung tissue -susceptible to shock wave injury- Hemoptysis
and pulmonary contusion.• Styrofoam padding.
• No incisions• No surgery• No lengthy hospital stays • No lengthy recovery periods
Advantages of lithotripsy
• Some discomfort. • Medicine to prevent infection. • Passing sand-like particles in
urine
Disadvantages of lithotripsy
• Weight > 300 pounds (140 kg)• Pregnant (absolute NO)• Bleeding diathiasis (relative)• Non- functional kidneys• Pacemaker in-situ• Contraindicated to anaesthesia or x-rays.
Who should not have lithotripsy?
Laser Lithotripsy
• Ureteral stones low in ureter and not amenable to ESWL.
• laser beam of 504-nm.• organic green dye. • Laser beam -absorbed by the stones• pulsatile energy is released - disintegration of the
stones
pulsed dye laser
• The anaesthesia method for ESWL procedures
Depends upon:• The level of patient consciousness• The spontaneous breathing ability • Need for intensive monitoring• Anaesthesia recovery time.
Anaesthetic choices for lithotripsy
• Patient’s ASA class.• Model of lithotripter – high-energy lithotripters
may require deeper level of sedation• Availability of certified anaesthetist or nurse
anaesthetist.• Location of lithotripsy treatment
General anesthesia
Analgesia-sedation
Spinal anesthesia
Epidural anesthesia
Flank infiltration ± intercostal
blocks
Monitored anesthesia care
Conscious sedation
Anaesthetic choices for lithotripsy
Conscious Sedation
• An altered state of consciousness• Minimizes pain and discomfort - analgesics and
sedatives.• Patients able to speak and respond.• A brief period of amnesia may erase the patient’s
memory of the procedure.
• Benefits:
• Ease of administration• Minimal equipment.• Rapid recovery time.
• Drawbacks:
• Diaphragmatic excursion• Increase treatment time • Decrease effectiveness of the treatment.• Unpleasant memories
Monitored Anesthesia Care(MAC Anesthesia)
• Patient protects the airway• Requires active participation of anaesthesiologist. • Can induce loss of normal protective reflexes • Loss of consciousness• The level varies widely during a single case and
from case to case.
• Benefits:
• A deeper level of anaesthesia• Diaphragmatic excursion is reduced• Improving treatment times and effectiveness
• Drawbacks:
• Must be administered by qualified anesthesia personnel.
• Diaphragmatic excursion when anaesthesia is not deep enough
• This can increase treatment time and/or decrease the effectiveness of the treatment
General Anesthesia (GA)
• Drug-induced loss of consciousness• Cannot be aroused, even by painful stimulation.• Impaired respiratory and cardiovascular function• If PPV → Securing airway using:• Laryngeal Mask Airway• Endotracheal Intubation
Benefit
• Rapid onset• Control of patient movement. • Ventilation parameters –controlled.• Decrease stone movement with respiration,• Effective stone targeting and fragmentation.
Drawback
• Morbidity and potential mortality • Longer hospital stay,• Expensive• Prolonged recovery• Strict monitoring • Equipment and personel
GA preferable
- Children,- Extremely anxious individuals, - Anticipated lengthy treatment • bilateral ESWL, • concomitant renal and ureteral stones, • calculi composed of cystine, or brushite, COM.
MAC VS GA
• MAC• Rapid recovery• Bypasses PACU• Fastracking surgery
• G.A• Prolonged recovery• Shorter duration of
ESWL procedure• Less opioids required
Regional Anesthesia
• Easier to provide.• Controlled loss of sensation.• Better analgesia.• Methods for shock wave include:• Spinal Anesthesia• Epidural Anesthesia
Epidural anesthesia
• Early recovery , good analgesia.
• LOR with saline• Smallest amount of air if necessary-provides
an interface → dissipation of shock wave energy and local tissue injury.
Spinal anesthesia
• Rapid onset• Hypotension is higher.• The incidence of hypotension with general ,
epidural, and spinal anaesthesia was 13%, 18%, and 27%, respectively.
Regional anaesthesia
• Drawbacks
• Postdural puncture headache (42%)• Transient neurological symptom• Urinary retention• Pruritis • Hypotension
• Flank infiltration ± intercostal blocks.
• L.A infiltration of flank ± intercostal blocks + intravenous sedation →adequate anesthesia avoids hypotension.
• Analgesia -sedation
Intravenous analgesia-sedation in various combinations has been used successfully
Thanks!!!