A needle assembly comprising: a housing (212, 312, 412, 512, 612, 712, 1012) defining a housing interior (220, 320, 520, 620, 720), said housing (212, 312, 412, 512, 612, 712, 1012) comprising at least one cannula (236, 336, 436, 536, 632, 732, 1036) having a patient puncture tip (438, 538, 638, 738, 1038) extending from a first end (214, 414, 514, 614, 714, 1014) of the housing (212, 312, 412, 512, 612, 712, 1012) and a non-patient puncture tip (462, 562, 662, 762, 1062) extending from a second end (216, 416, 516, 616, 716, 1016) of the housing (212, 312, 412, 512, 612, 712, 1012), the non-patient puncture tip (462, 562, 662, 762, 1062) and the patient puncture tip (438, 538, 638, 738, 1038) being in fluid communication with each other within the housing interior (220, 320, 520, 620, 720); and a porous vent (900, 910, 920) positioned within the housing interior separating the housing interior (220, 320, 520, 620, 720) into a first chamber (226, 326, 426, 526, 626, 726, 1026) and a second chamber (427, 527, 627, 727, 1027), the porous vent (900, 910, 920) including pores for passage of fluid therethrough from the first chamber (226, 326, 426, 526, 626, 726, 1026) to the second chamber (427, 527, 627, 727, 1027), said porous vent (900, 910, 920) including a blocking member to control flow of the fluid such that the fluid flows in an axial direction through the porous vent (900, 910, 920), wherein the housing (212, 312, 412, 512, 612, 712, 1012) includes a rear hub (680b, 680c, 680d) having a cylindrical portion extending therefrom and into the first chamber (226, 326, 426, 526, 626, 726, 1026) toward the first end (214, 414, 514, 614, 714, 1014) of the housing to define a portion of the first chamber (226, 326, 426, 526, 626, 726, 1026), said cylindrical portion (682b, 682c, 682d) forming at least a portion of the blocking member, and wherein the sole communication path between the housing interior (220, 320, 520, 620, 720) and the external environment is via the patient puncture tip (438, 538, 638, 738, 1038). a housing (212, 312, 412, 512, 612, 712, 1012) defining a housing interior (220, 320, 520, 620, 720), said housing (212, 312, 412, 512, 612, 712, 1012) comprising at least one cannula (236, 336, 436, 536, 632, 732, 1036) having a patient puncture tip (438, 538, 638, 738, 1038) extending from a first end (214, 414, 514, 614, 714, 1014) of the housing (212, 312, 412, 512, 612, 712, 1012) and a non-patient puncture tip (462, 562, 662, 762, 1062) extending from a second end (216, 416, 516, 616, 716, 1016) of the housing (212, 312, 412, 512, 612, 712, 1012), the non-patient puncture tip (462, 562, 662, 762, 1062) and the patient puncture tip (438, 538, 638, 738, 1038) being in fluid communication with each other within the housing interior (220, 320, 520, 620, 720); and a porous vent (900, 910, 920) positioned within the housing interior separating the housing interior (220, 320, 520, 620, 720) into a first chamber (226, 326, 426, 526, 626, 726, 1026) and a second chamber (427, 527, 627, 727, 1027), the porous vent (900, 910, 920) including pores for passage of fluid therethrough from the first chamber (226, 326, 426, 526, 626, 726, 1026) to the second chamber (427, 527, 627, 727, 1027), said porous vent (900, 910, 920) including a blocking member to control flow of the fluid such that the fluid flows in an axial direction through the porous vent (900, 910, 920), wherein the housing (212, 312, 412, 512, 612, 712, 1012) includes a rear hub (680b, 680c, 680d) having a cylindrical portion extending therefrom and into the first chamber (226, 326, 426, 526, 626, 726, 1026) toward the first end (214, 414, 514, 614, 714, 1014) of the housing to define a portion of the first chamber (226, 326, 426, 526, 626, 726, 1026), said cylindrical portion (682b, 682c, 682d) forming at least a portion of the blocking member, and wherein the sole communication path between the housing interior (220, 320, 520, 620, 720) and the external environment is via the patient puncture tip (438, 538, 638, 738, 1038).