A cannula locator device, comprising: a catheter adapter having a proximal end and a distal end, the catheter adapter including a catheter that extends from the distal end of the catheter adapter; a needle hub having a proximal end and a distal end, the needle hub including a cannula that extends from the distal end of the needle hub, the cannula being positioned within and extending through the catheter adapter and the catheter such that a distal tip of the cannula extends distally beyond a distal end of the catheter; a flash chamber coupled to the proximal end of the needle hub, the cannula forming a fluid pathway into the flash chamber; a needle shield having a proximal end and a distal end, the distal end of the needle shield being coupled to the proximal end of the catheter adapter, the needle hub and the flash chamber being contained within the needle shield; a sheath having a proximal end and a distal end, the distal end of the sheath being positioned adjacent the distal tip of the cannula, the sheath extending proximally through the cannula, the flash chamber, and out through the proximal end of the needle shield; one or more light emitting optical fibers and one or more receiving optical fibers contained within the sheath, a distal end of each of the one or more emitting optical fibers and the one or more receiving optical fibers being positioned at the distal end of the sheath, a proximal end of each of the one or more emitting optical fibers and the one or more receiving optical fibers extending within the sheath through the proximal end of the needle shield; a light emitter that is configured to emit light into the proximal end of each of the one or more emitting optical fibers; and a wavelength detector comprising one or more photodiodes configured to receive a portion of reflected light and convert the portion into an electrical signal; a signal processor coupled to the wavelength detector and configured to receive the electrical signal to determine an increased amount of red color in the portion of reflected light when the distal tip of the cannula is within a patient's vasculature. a catheter adapter having a proximal end and a distal end, the catheter adapter including a catheter that extends from the distal end of the catheter adapter; a needle hub having a proximal end and a distal end, the needle hub including a cannula that extends from the distal end of the needle hub, the cannula being positioned within and extending through the catheter adapter and the catheter such that a distal tip of the cannula extends distally beyond a distal end of the catheter; a flash chamber coupled to the proximal end of the needle hub, the cannula forming a fluid pathway into the flash chamber; a needle shield having a proximal end and a distal end, the distal end of the needle shield being coupled to the proximal end of the catheter adapter, the needle hub and the flash chamber being contained within the needle shield; a sheath having a proximal end and a distal end, the distal end of the sheath being positioned adjacent the distal tip of the cannula, the sheath extending proximally through the cannula, the flash chamber, and out through the proximal end of the needle shield; one or more light emitting optical fibers and one or more receiving optical fibers contained within the sheath, a distal end of each of the one or more emitting optical fibers and the one or more receiving optical fibers being positioned at the distal end of the sheath, a proximal end of each of the one or more emitting optical fibers and the one or more receiving optical fibers extending within the sheath through the proximal end of the needle shield; a light emitter that is configured to emit light into the proximal end of each of the one or more emitting optical fibers; and a wavelength detector comprising one or more photodiodes configured to receive a portion of reflected light and convert the portion into an electrical signal; a signal processor coupled to the wavelength detector and configured to receive the electrical signal to determine an increased amount of red color in the portion of reflected light when the distal tip of the cannula is within a patient's vasculature.