Tissue ischemia resulting in wounds that are characterized as a partial-thickness injury with a blister is considered:A) Stage 1
Tissue pressures that exceed the pressure of the microcirculation (30 mm Hg) result in tissue ischemia. Frequent or prolonged ischemic insults will ultimately result in tissue damage. Areas of bony prominence are particularly prone to ischemia, the most common areas being ischial tuberosity (28%), trochanter (19%), sacrum (17%), and heel (9%). Tissue pressures can measure up to 300 mm Hg in the ischial region during sitting and 1 50 mm Hg over the sacrum while lying supine. Muscle is more susceptible than skin to ischemic insult due to its relatively high metabolic demand. Wounds are staged as follows: stage 1, nonblanching erythema over intact skin; stage 2, partial-thickness injury (epidermis or dermis) blister or crater; stage 3, full-thickness injury extending down to, but not including, fascia and without undermining of adjacent tissue; and stage 4, full-thickness skin injury with destruction or necrosis of muscle, bone, tendon, or joint capsule.