Lacerations: Pathophysiology (Nursing)

00:01 Now we're going to take a look at the pathophysiology of a laceration.

00:04 So first we're going to start with five phases.

00:07 You start with the initial response all the way through the hemostasis inflammatory proliferative and the maturation phase.

00:15 So let's back up to the initial response.

00:17 This happens immediately.

00:18 It's the vasoconstriction that happens immediately after the injury.

00:22 Now this should last 5 to 10 minutes.

00:24 Next up is the hemostasis phase.

00:27 Well this is when we end up with that clot that's going to help the patient from hemorrhaging.

00:31 Right. So how does that happen? Well, the platelets aggregate and they adhere.

00:36 They stick to the exposed collagen.

00:38 Then you have the activation of the coagulation cascade.

00:41 And that's what leads to the fibrin clot forming.

00:44 Now this temporary matrix forms like kind of a scaffold so the cells can migrate there.

00:49 So initial response vasoconstriction hemostasis means you're ending up with a clot that's going to stop the bleeding. Then we move into the inflammatory phase.

00:59 Now that can last 1 to 4 days.

01:01 You end up with vasodilation and you have this increased capillary permeability.

01:06 Right. Things can go back and forth across that capillary membrane.

01:10 So the neutrophils are coming. This is where they infiltrate so they can combat bacteria.

01:14 Right. Those are our fighters.

01:15 They can help combat the bacteria prevent infection and remove any debris from the wound.

01:21 Now the macrophages arrive for phagocytosis and they release the growth factors.

01:26 Now the clinical signs you'll be looking for include erythema or redness.

01:31 You'll watch for edema, which is a swelling, warmth and pain.

01:35 So this is what you should expect to see in a client who has a laceration in the first 1 to 4 days. Next up is a proliferative phase.

01:44 This is 4 to 21 days. Well, this gets pretty interesting because the fibroblasts produce this collagen and they make an extracellular matrix.

01:53 Now angiogenesis creates new blood vessels right.

01:55 This is the phase of construction.

01:58 You have epithelialization which means your epithelial cells are going to migrate and proliferate. That skin is going to be rebuilt.

02:06 So the wound is going to contract and it's going to get smaller and smaller from the initial laceration. Remember you have those uneven edges.

02:13 But here in this phase, in the proliferative phase when things are getting built, that wound is going to get smaller and smaller as all of this is built to come together.

02:23 Now last you have the maturation phase.

02:25 This can be 21 days up to 1 to 2 years, depending on the size of the wound and where it's located. So big stuff happens here, but it's mostly under cover, right? The collagen gets remodeled and it gets reorganized.

02:39 Not going to need as much of the blood supply.

02:41 So you're going to see a decrease in the vascularity that you had in the previous phase, and also in the density of the cells.

02:48 This is where the scar tissue forms, and it's going to have a gradual increase in how strong that scar is. Now, when everything is done, the final scar is about approximately 80% of the strength of the unwounded skin.

03:03 So it does pretty good before the laceration when you finally get that final scar, it's going to be about 80% as strong as the previous skin.