Intra-vascular apparatus for medical use, namely invasive blood pressure monitoring kit comprising medical pressure tubing for connection to an IV cannula, pressure transducer and stopcock; intra-vascular blood gas concentration monitoring apparatus; intra-vascular blood gas concentration monitoring systems; venous catheters for human use; arterial blood pressure measuring apparatus; catheters for medical use; vascular access kits consisting primarily of a sterile field sheet and a Luer activ...