Yang X, Manninen H, Ji H, Soimakallio S. Influence of carbon dioxide gas perfusion to thermal distribution of sapphire probecolon; a comparative study with saline. Invest Radiol 1994; 29colon;553-557RATIONALE AND OBJECTIVES.A previous study confirmed that the direct laser-thermal conduction of the sapphire probe with carbon dioxide gas perfusion increased the width of the laser-recanalized channel. This caused us to further investigate the thermal distribution characteristics of the sapphire probe when lasing with CO2gas perfusion.METHODS.The surface temperature of a sapphire probe in a circulation model using 37deg;C flowing whole blood was measured. Two hundred and sixteen measurements were obtained by directly contacting a flexible thermocouple wire onto the sapphire probe at different sitescolon; 1) metal connector; 2) lateral side of the sapphire crystal; 3) top of the sapphire crystal; and 4) 3 mm in front of the sapphire probe. During lasing with a neodymium-yttrium-aluminum garnet (Nd-YAG) laser, the CO2gas or saline was infused through the sapphire probe at different flow rates.RESULTS.The lateral side of the sapphire crystal was heated up to 75deg;C when lasing without any perfusion, but up to 220deg;C when lasing with CO2gas perfusion. At all four sites, the mean temperature increases were statistically higher (P .01) with CO2gas than with saline perfusion. The mean peak temperatures increased with increasing flows of CO2gas perfusion and decreased with increasing flows of saline perfusion.CONCLUSIONS.The thermal conduction from the sapphire probe can be significantly enhanced by increasing flows of CO2gas perfusion. This may play an important role in creating a greater diameter of the recanalized channel and in better delaying the formation of restenosis or re-occlusion after laser recanalization of atheromatous arteries.
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