Laser oximetry: A novel noninvasive method to determine changes in penile hemodynamics in an anesthetized rabbit model

This study was designed to determine the utility and validity of laser oximetry in measuring changes in penile hemodynamics. Anesthetized male New Zealand White Rabbits were divided into 2 groups, and penile hemodynamics were assessed by either laser oximetry (oxyhemoglobin, deoxyhemoglobin concentration, and oxygen saturation) or intracavernosal pressure (ICP) monitoring during penile erection induced by pelvic nerve stimulation (PNS) or intracavernosal administration of phentolamine, nitroprusside, papaverine, or sildenafil. PNS caused significant frequency-dependent increases in penile ICP. PNS also caused significant increases in penile tissue oxyhemoglobin concentrations and tissue oxygen saturation in a frequency-dependent manner. The changes in oxyhemoglobin concentrations and oxygen saturation correlated with frequency-dependent increases in ICP. Intracavernosal vasoactive drug administration produced significant increases in ICP, tissue oxyhemoglobin concentration, oxygen saturation, and duration of response as a function of increasing drug concentration. Laser oximetry permits reproducible and valid assessment of changes in penile hemodynamics comparable to conventional ICP measurements. Thus, we consider laser oximetry a reliable technique in evaluating penile hemodynamics. Its sensitivity in detecting small changes in oxyhemoglobin concentration and its noninvasive nature make it advantageous over invasive methods such as ICP monitoring and laser Doppler flowmetry.