Parameter Determination; Setting The Pulse Width - COOK Medical H-30 User Manual

Warnings and precautions for the safe use of holmium laser fibers
• Changes in the tissue texture and color are the best indicators of the laser's effect.
The recommended power settings are less important than the observed tissue effect.
Specific pulse width depends on the tissue and is left to the surgeon's preference and
best medical judgment.
• Use the lowest possible power settings required to achieve the desired tissue effect
for treatment.
• Higher energy may be necessary to achieve the desired tissue effects if cooled
irrigant is utilized. Higher power settings may increase chances of damage to the
laser fiber.
• The use of mechanical pressure on the laser fiber does not increase its cutting or
vaporization effects but may induce bleeding, thermal damage and fiber destruction.
• The risk of combustion, perforation, and laser induced hemorrhage, any of which can
cause patient death, must be fully explained to the patient prior to surgery.
• Endoscopic treatment may result in adverse reactions such as fever, chills, sepsis,
edema, and hemorrhage. In extreme cases, death may occur due to procedural
complications, concurrent illness, or the application of laser radiation.

Parameter Determination

Choosing the ideal laser fiber
Cook Medical's holmium laser fibers for use with the H-30 come in 150, 200, 273, 365,
550 and 940 µm core diameters. Larger core fibers will allow the use of higher power
but are less flexible. Higher pulse energy and larger fibers result in larger ablation
volumes. Large core fibers will also be consumed less during procedures because of the
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greater thermal mass and ability to dissipate parasitic thermal energy faster. Users are
encouraged to select the largest core size feasible considering the flexibility needed to
reach the target and the size of the endoscope's working channel.
Kang HW, Lee H, Teichman JMH, et al. Dependence of calculus retropulsion on pulse duration during Ho: YAG laser lithotripsy.
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Lasers Surg Med. 2006;38(8):762-772.

Setting the Pulse Width

Lithotripsy
• Short pulse width will cause larger fragmentation particulates (bust stone) but will
also cause greater retropulsion.
• Long pulse width will cause smaller fragmentation particulates (dust stone) and will
cause less retropulsion.
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Chapter 4
Indications & Instructions for Use
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