CAISS External and Thermal 5 — Questions and Answers
Question 1: What TBSA threshold for full-thickness burns in adults generally warrants transfer to a burn center according to ABA criteria?
- ≥ 1% TBSA
- ≥ 5% TBSA
- ≥ 10% TBSA (Correct answer)
- ≥ 25% TBSA
Correct answer: ≥ 10% TBSA
The American Burn Association recommends burn center transfer for full-thickness burns of ≥ 10% TBSA in adults.
Question 2: A contusion (bruise) documented as 'large, covering the entire lateral thigh' would typically receive which AIS code?
- AIS 1
- AIS 2 (Correct answer)
- AIS 3
- AIS 4
Correct answer: AIS 2
Large contusions without deep structural damage are generally coded AIS 2 (moderate) in the External body region.
Question 3: Which formula is used to calculate the Parkland fluid resuscitation volume for burn patients in the first 24 hours?
- 2 mL × kg × %TBSA burned
- 4 mL × kg × %TBSA burned (Correct answer)
- 1 mL × kg × %TBSA burned
- 3 mL × kg × %TBSA burned
Correct answer: 4 mL × kg × %TBSA burned
The Parkland formula uses 4 mL × body weight (kg) × %TBSA burned for Lactated Ringer's solution in the first 24 hours.
Question 4: In AIS, the term 'NFS' (Not Further Specified) in an injury descriptor indicates:
- The injury is fatal
- Sufficient detail to assign a more specific code is lacking (Correct answer)
- The injury is non-fatal and superficial
- The coder should skip the injury
Correct answer: Sufficient detail to assign a more specific code is lacking
NFS means the documentation lacks enough detail to assign a more specific AIS code, so the coder uses the general/NFS descriptor.
Question 5: A high-voltage electrical burn (> 1000 V) differs from a flame burn primarily because it:
- Only affects the skin surface
- Causes internal tissue destruction along the current path (Correct answer)
- Never produces entry/exit wounds
- Is coded identically to a thermal flame burn in AIS
Correct answer: Causes internal tissue destruction along the current path
High-voltage electrical injury causes deep tissue destruction along the current pathway, including muscle and vessels, beyond what the surface wound suggests.
Question 6: When calculating ISS for a patient with a serious (AIS 3) burn injury and a critical (AIS 5) thoracic injury, the burn injury's contribution to ISS is:
- 9 (3²) (Correct answer)
- 25 (5²)
- 0, because the thorax score is higher
- Averaged with the thorax score
Correct answer: 9 (3²)
ISS uses the squared AIS of the highest injury in each of the six body regions; the External/Thermal region contributes 3² = 9 independently.
Question 7: A patient with a full-thickness burn to the entire head and neck (adult) has approximately what TBSA involved?
- 4.5%
- 9% (Correct answer)
- 13.5%
- 18%
Correct answer: 9%
In the adult Rule of Nines, the head and neck together account for 9% of TBSA.
CAISS External and Thermal 5
What TBSA threshold for full-thickness burns in adults generally warrants transfer to a burn center according to ABA criteria?