Principles of Surgery & Wound Healing Flashcards

A patient is in Class III haemorrhagic shock. What is the estimated blood loss and the expected physiological response?

Answer: 1500–2000 mL; marked tachycardia, decreased BP, decreased urine output

ATLS Class III shock involves 1500–2000 mL blood loss (30–40% circulating volume), producing: HR >120, systolic BP decreased, pulse pressure narrowed, RR 30–40, urine output 5–15 mL/hr, and confusion/anxiety. Immediate fluid resuscitation and likely blood transfusion are required.

Which growth factor is the primary driver of the proliferative phase of wound healing?

Answer: Platelet-derived growth factor (PDGF)

PDGF is released from platelets in the initial haemostatic phase and is one of the primary chemotactic and mitogenic signals for fibroblasts, initiating the proliferative phase. TGF-β drives fibrogenesis and scar formation. VEGF drives angiogenesis within the proliferative phase.

What type of collagen is predominantly synthesised during the proliferative phase of wound healing and replaced in the remodelling phase?

Answer: Type III collagen

Type III collagen (fine, immature) is predominantly produced during the proliferative phase of wound healing. During the remodelling phase (weeks to months), Type III collagen is gradually replaced by the stronger Type I collagen as wound tensile strength increases. The wound never regains 100% pre-injury strength (maximum ~80%).

What is primary intention wound healing?

Answer: Healing by direct apposition of wound edges with sutures, clips, or glue

Primary intention healing occurs when wound edges are brought together directly (sutures, staples, adhesive strips, or glue), allowing the wound to heal with minimal scar tissue. This is used for clean surgical incisions. Infection risk is low and healing is faster than secondary intention.

Which sign indicates early systemic inflammatory response syndrome (SIRS) in a surgical patient?

Answer: Temperature 38.6°C, heart rate 102 bpm, RR 22 breaths/min, WBC 13.5 × 10⁹/L

SIRS is diagnosed by two or more of: temperature >38°C or 90 bpm, RR >20 breaths/min or PaCO2 12 or <4 × 10⁹/L. Option B meets three criteria: temperature 38.6°C, HR 102, RR 22, and WBC 13.5 × 10⁹/L.

Keloid scarring differs from hypertrophic scarring in which key way?

Answer: Hypertrophic scars remain within wound margins; keloid scars extend beyond the original wound boundary

Keloid scars grow beyond the original wound boundary and may continue to enlarge over time; they do not regress spontaneously and are more common in darker skin types and in certain anatomical sites (sternum, shoulders, earlobes). Hypertrophic scars remain within the wound margins and may regress with time.