Anaesthetic choices for
Dr Nida Fatima
Department of Anaesthesia and Critical care,
JN Medical college and hospital
• Prevalence of stone disease -1% to 15%.
• Varies- age, gender, race, and geographic
• stone formation - migrated -lower to the
upper urinary tract.
• once limited to men is increasingly gender
• Lithotripsy( Greek) meaning "stone crusher“.
• 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
Extracorporeal shock wave lithotripsy
• Disintegration of urinary stones in the ureter and
• 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.
MANAGEMENT OF RENAL CALCULI by
< 2cm in diameter and/or surface area < 500 mm2
Treatment : ESWL mono-therapy
> 2cm in diameter and/or surface area > 500
Treatment : PCNL +/- ESWL
• Comprises of:
• spark plug
• Energy reflector
• Energy concentrator
Spark plug Energy vaporize water
external shock wave
Release energy patient’s body
Crushed to pieces
- The sudden expansion
of air bubbles created
sets up a pressure
wave (shock wave)
- Focused onto F2 focus
- Exponential reduction
energy of wave beyond
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
• To increase the efficacy of the treatment :
• decreased tidal volumes ,increased
respiratory rates, high-frequency jet
Physiological effects of lithotripsy
• Mechanical stimulation of myocardium and
• Atrial premature contraction
• Ventricular premature contraction
• Atrial fibrillation
• Supraventricular tachycardia
• Ventricular tachycardia
When a patient is placed in a water bath:
• 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
Increased Central blood volume
Increased Central venous pressure
Increased Pulmonary artery pressure
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.
• Diuresis, natriuresis, and kaliuresis.
• ↓ADH and renal prostaglandins
• This heat transfer is augmented -vasodilation
produced by general or epidural anesthesia.
• Hypothermia and hyperthermia have been
• The pathogenesis -multifactorial.
• - Both cutenous and visceral nociceptors
Visceral nociceptors –
• musculoskeletal pain receptors
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
• 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
• 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
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?
• Ureteral stones low in ureter and not amenable to
• laser beam of 504-nm.
• organic green dye.
• Laser beam -absorbed by the stones
• pulsatile energy is released - disintegration of the
pulsed dye laser
• The anaesthesia method for ESWL
• 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
• Availability of certified anaesthetist or nurse
• Location of lithotripsy treatment
Anaesthetic choices for lithotripsy
• An altered state of consciousness
• Minimizes pain and discomfort - analgesics and
• Patients able to speak and respond.
• A brief period of amnesia may erase the patient’s
memory of the procedure.
• Diaphragmatic excursion
• Increase treatment time
• Decrease effectiveness of the treatment.
• Unpleasant memories
Monitored Anesthesia Care
• 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.
• A deeper level of anaesthesia
• Diaphragmatic excursion is reduced
• Improving treatment times and effectiveness
• Must be administered by qualified anesthesia
• 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
• Rapid onset
• Control of patient movement.
• Ventilation parameters –controlled.
• Decrease stone movement with respiration,
• Effective stone targeting and fragmentation.