| 摘要 |
<p>A vascular access device includes a needle section (102; 142) and a dilator section (112; 150). The dilator is coaxially mounted on the needle forming a space (122; 170) between the needle and the dilator and arranged so that blood flowing in the needle (104; 144) flows into the space (122; 170) through at least one lateral opening (120; 149) in the needle. Optionally, a sheath section (160) comprising a sheath (162) is coaxially mounted on the dilator (152) optionally forming a second space (174) between the dilator (152) and the sheath (160), the dilator in this case being provided with an opening (172) or spaces arranged so that blood flowing in the needle (144) and then through the lateral opening (149) flows into the second space (174). One or more small openings, pores or spots of porous material on the dilator, or a porous vent (128) on the dilator hub (116; 154), allows air or gas to escape from the space (122; 170), or when present the second space (174), yet retain blood. The dilator (114; 152) or the sheath (162) is clear, semi-opaque, or translucent, so that when blood flows into needle (104; 144) and then into the space (122; 170) or when present the second space (174) may be seen to indicate that the distal tip (124; 176) of the needle (104; 144) has punctured a blood vessel.</p> |
