Trauma / surgery

Question 1

What is REBOA, the different zones where it can be used, and the time of use

Answer 1

REBOA = resuscitative endovascular balloon occlusion of the aorta

Zone 1 = very proximal (before coeliac artery), used to prioritize cerebral and coronary perfusion in unstable patients.
Max 30-45 min

Zone 2 = between coeliac and renal artery, for intra-abdominal hemorrhage

Zone 3 = between renal artery and aortic trifurcation, for pelvic hemorrhage.
Max 60 min

Question 2

What are the results of the CRASH-2 study on the use of TXA in bleeding human trauma patients

Answer 2

TXA improved mortality when given within 3h of trauma (without increased risk of thrombosis), but increased mortality when given past 3h
(benefit decreases by 10% for every 15 min delay)

Question 3

What is the mechanism of TXA?

Answer 3

Lysine derivative that blocks the lysine site on plasminogen –> prevents binding of TPA –> prevents fibrinolysis

Question 4

What is the survival to discharge rate following trauma in dogs and cats

Answer 4

Dogs: 90%
Cats: 75%

Question 5

Where are injuries located most often following gunshot wounds in civilian dogs

Answer 5

Appendicular skeleton > thorax > head / neck > abdomen

Question 6

What volume of blood loss does it take to start having severe signs of shock

Answer 6

> 15% total blood volume

Question 7

What parameters have been found to predict need for blood transfusion in dogs with trauma

Answer 7

• PCV/TS (PCV<39 with TS<4.5)
• Base excess (<-6.6)

Question 8

What proportion of dogs with a traumatic hemoperitoneum require surgery

Answer 8

6%

Question 9

What is a contra-indication to hypotensive resuscitation

Answer 9

Traumatic brain injury

Question 10

How is the severity of injuries related to the number of stories of the fall in high-rise syndrome in dogs and cats

Answer 10

• Dogs: injury severity proportional to height of fall
• Cats: severity increases until 7 stories then remains constant due to adjustments in their surface area. They have more limb injuries under 5 stories and more trunk injuries after 5-7 stories.
  Maximal speed reached by cats = 100 km/h

Question 11

Where are injuries most commonly located in high rise syndrome

Answer 11

Head (facial injuries&raquo_space; TBI), thorax (pulmonary contusions, pneumothorax&raquo_space;diaphragmatic hernia), extremities

Question 12

What is a hallmark of high-rise syndrome in cats and a complication if left untreated?

Answer 12

Hard palate fractures

Oronasal fistula is a complication of untreated and medically managed hard palate fractures

Question 13

What is a rare but severe abdominal complication of high-rise syndrome in cats

Answer 13

Pancreatic rupture / traumatic pancreatitis

Question 14

What is the mortality associated with high-rise syndrome? What is a negative prognostic factor in cats?

Answer 14

6-17%

Presence of abdominal injuries increases mortality by 2.5 times in cats

Question 15

What are the 4 classes of hemorrhage (from humans)

Answer 15

Class I = loss up to 15% of blood volume -> minimal clinical symptoms except tachycardia

Class II = loss of 15-30% -> tachycardia, tachypnea, decrease in pulse pressure

Class III = loss of 30-40% -> pale MM, prolonged CRT, depression, hypotension

Class V = loss of > 40% -> life-threatening, signs of shock

Question 16

List some predictors of mortality in dogs with trauma

Answer 16

• Head trauma
• Arrhythmias
• Body wall hernias
• Recumbency at the time of admission
• MODS, ARDS, DIC, requirement for ventilation, requirement for vasopressors (no kidding)
• Elevated lactate and creatinine but use of a comprehensive score is recommended

Question 17

What causes hyperglycemia following trauma

Answer 17

• Catecholamines
• Glucagon
• Cortisol
• Growth hormone

Question 18

What is the difference between a penetrating and a perforating injury

Answer 18

A perforating injury passes completely through the body cavity

Question 19

Define a flail chest and a pseudo flail chest

Answer 19

Flail chest: Fractures of 3 or more adjacent ribs at 2 or more locations causing a segment to move independently from the chest wall and have paradoxical movements with the breathing

Pseudo flail chest: Paradoxical movement of a portion of the chest due to severe intercostal muscle injury without rib fractures around

Question 20

What are the 3 main components of splenic vascularization? Where do they originate from?
What artery should be preserved when doing a splenecomty

Answer 20

• Splenic artery and vein
• Short gastric arteries and veins
• Left gastroepiploic artery and vein

All originate from celiac artery (from abdominal aorta)

Must be careful to preserve pancreatic arteries (coming from the splenic artery) when ligating vessels

Question 21

What are the 4 abdominal muscles that constitute the abdominal wall? What layer holds sutures?

Answer 21

From out to in:

• Rectus abdominis (parallel to linea alba)
• Internal abdominal oblique (runs cranioventrally)
• External abdominal oblique (runs caudoventrally)
• Transversus abdominis (transverse to linea alba)

The external rectus sheath holds sutures

Question 22

What are common locations of abdominal wall hernias

Answer 22

• Paracostal
• Inguinal
• Umbilical
• Scrotal
• Cranial pubic ligament rupture
• Ventral / subxiphoid
• Femoral
• Dorso-lateral

Question 23

Describe some of the characteristics of the systemic response to severe injury

Answer 23

• Extracellular release of DAMPs or alarming from activated neutrophile or necrotic cells –> activation of innate immune system and complement –> production and release of inflammatory mediators (IL-6, IL-8) –> SIRS
• Platelets activated by trauma can also contribute to release of proinflammatory mediators
• Neutrophils migrate across the damaged vascular endothelium, become sequestered by “bystanders” organs –> organ dysfunction
• Simultaneously, a compensatory anti-inflammatory response occurs –> IL-10 and TGF-beta

Question 24

Name 3 bacterias commonly isolated from bite wounds

Answer 24

• Pasteurella spp
• Staph spp
• Strep spp

Question 25

What are the 3 categories evaluated in the MGCS?

Answer 25

- Motor activity - Brainstem reflexes - Level of consciousness

Question 26

What are the 2 components of trauma associated coagulopathy (TAC)?

Answer 26

- Endogenous coagulopathy with concurrent tissue hypoperfusion (acute coagulopathy pf trauma shock) - Syndrome that occurs later and is exacerbated by resuscitation practices (resuscitation associated coagulopathy)

Question 27

What are the 3 phases of healing?

Answer 27

1. Inflammatory phase (first 5 days): - PLT activated by hemorrhage and endothelial injury --> attract neutrophils (6h after injury) + monocytes (12h) (debridement phase begins) - Vasodilation from PGs, histamines, kindness allow leukocyte migration to the wound bed - Neuts remove extracellular debris / monocytes stimulate fibroblastic activity, collagen synthesis, angiogenesis / macrophages remove necrotic tissue, bacteria, foreign material 2. Prolific phase (begin day 4, lasts 2-3 wks): - angiogenesis, granulation tissue, epithelialization 3. Maturation phase (day 17-20 up to years): - wound contraction and remodeling of fibre bundles - Scar is only 80% as strong as original tissue

Question 28

Describe the pathophysiology of acute coagulopathy of trauma-shock

Answer 28

Characterized by hyaocoagulability with hyperfibrinolysis Severe trauma and widespread tissue injury --> recessive plasma catecholamine --> generalized endothelial activation --> release of thrombomodulin, systemic coagulation activation, consumption of clotting factors and platelets --> pro coagulable thrombin activates protein C (potent endogenous anticoagulant) --> inhibits factor Va and VIIIa, as well as plasminogen activator inhibitor 1 and thrombin activatable fibrinolytic concurrently --> hyperfibrinolysis catecholamine surge also damages endothelial glycocalyx --> shedding and release of endogenous anticoagulants (heparin) and profibrinolytic agents

Question 29

Briefly, how does platelet dysfunction occur in TAC?

Answer 29

Widespread release of ADP following tissue trauma may prematurely activate platelets leading to their exhaustion and retention into circulation.

Question 29

List metabolic consequences of trauma

Answer 29

- Sympathoadrenal activation - Neuroendocrine activation - Hyperglycemia - Hyperlactatemia - Metabolic acidosis - Hypothermia - GI injury +/- translocation - Systemic inflammation - Acute traumatic coagulopathy

Question 30

Why do patients develop hyperglycemias after trauma?

Answer 30

Release of counter regulatory hormones (glucagon, growth hormone, cortisol, catecholamine) - Epinephrine --> proteolysis, glycogenolysis (glycogen --> glu), inhibition of insulin mediated glucose uptake by muscle - Cortisol --> gluconeogenesis (amino acid --> glu), inhibits insulin activity, exacerbates effects of glucagon and epinephrine

Question 31

How are open fractures classified according to the Gustily-Anderson classification scheme?

Answer 31

I - open fracture with wound < 1cm; mild to moderate soft tissue bruising II - open fracture with wound > 1cm without extensive soft tissue damage III - Open fractures with extensive soft tissue damage IIIa - Extensive trauma with adequate tissue covering remaining, irrespective of wound size IIIb Extensive trauma with soft tissue loss, perinatal stripping and bone exposure IIIb - Extensive trauma associated with arterial blood supply injury

Question 32

What are indications for open reduction after traumatic joint luxation?

Answer 32

- Unsuccessful attempts at closed reduction - Joint reluxation - Chronic luxation - Concurrent intra-articular fractures - Internal stabilization is necessary fr adjacent long bone fractures - Neurologica injury suspected and exploration warranted

Question 33

Wounds classification:

Answer 33

- Clean: atraumatic, surgically created under aseptic conditions - Clean contaminated: minor break in aseptic surgical technique - Contaminated: Recent traumatic wound with bacterial contamination vs major break in surgical asepsis - Dirty or infected: older wound with exudate or obvious infection --> >10^5 organisms/g of tissue

Question 34

Name a few factors that can delay wound healing

Answer 34

- Poor O2 delivery (anemia, severe trauma, hypovolemia) - Hypoproteinemia (<2g/L --> decreases fibrous tissue deposition) - Chemotherapy/radiation therapy - Diabetess, uremia, liver disease - Steroids

Question 34

What are the burn degrees?

Answer 34

- 1st degree: superficial epidermis only - 2nd degree: epidermis and superficial dermis - 3rd degree: full thickness (entire epidermis and dermis) - 4th degree: full thickness with extension to muscle, tendon and bone

Question 35

How is the total surface body area (TBSA) burned estimated?

Answer 35

- Head --> 9% - Each forelimb --> 9% - Each hind limb --> 18% - Dorsal trunk --> 18% - Ventral trunk --> 18% > 20% of TBSA --> serious CV, metabolic and pulmonary derangements > 50% of TBSA --> poor prognosis

Question 36

Why can hypovolemic shock occur in burn patients?

Answer 36

As a result of capillary thrombosis leading to leakage of plasma. Most dramatic loss of fluids and electrolytes occurs within the first 12 hours.

Question 37

What volume of blood is held by a 2*2 gauze, 4*4 gauze, lap sponge

Answer 37

- 2*2 gauze holds 3.25 +/- 1.25 mL - 4*4 gauze holds 10 +/- 2 mL - lap sponge holds about 150 mL

Question 38

A pneumomediastinum can lead to air in which other cavities?

Answer 38

- Pneumothorax - SC emphysema - Pneumoperitoneum

Question 39

Explain the Macklin effect

Answer 39

Alveolus ruptures --> air dissects through peribronchovascular sheaths into pulmonary interstitium --> tracks along the perivascular space into the pulmonary hill and mediastinum --> pleural space