Trauma / surgery Flashcards
What is REBOA, the different zones where it can be used, and the time of use
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
What are the results of the CRASH-2 study on the use of TXA in bleeding human trauma patients
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)
What is the mechanism of TXA?
Lysine derivative that blocks the lysine site on plasminogen –> prevents binding of TPA –> prevents fibrinolysis
What is the survival to discharge rate following trauma in dogs and cats
Dogs: 90%
Cats: 75%
Where are injuries located most often following gunshot wounds in civilian dogs
Appendicular skeleton > thorax > head / neck > abdomen
What volume of blood loss does it take to start having severe signs of shock
> 15% total blood volume
What parameters have been found to predict need for blood transfusion in dogs with trauma
- PCV/TS (PCV<39 with TS<4.5)
- Base excess (<-6.6)
What proportion of dogs with a traumatic hemoperitoneum require surgery
6%
What is a contra-indication to hypotensive resuscitation
Traumatic brain injury
How is the severity of injuries related to the number of stories of the fall in high-rise syndrome in dogs and cats
- 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
Where are injuries most commonly located in high rise syndrome
Head (facial injuries»_space; TBI), thorax (pulmonary contusions, pneumothorax»_space;diaphragmatic hernia), extremities
What is a hallmark of high-rise syndrome in cats and a complication if left untreated?
Hard palate fractures
Oronasal fistula is a complication of untreated and medically managed hard palate fractures
What is a rare but severe abdominal complication of high-rise syndrome in cats
Pancreatic rupture / traumatic pancreatitis
What is the mortality associated with high-rise syndrome? What is a negative prognostic factor in cats?
6-17%
Presence of abdominal injuries increases mortality by 2.5 times in cats
What are the 4 classes of hemorrhage (from humans)
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
List some predictors of mortality in dogs with trauma
- 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
What causes hyperglycemia following trauma
- Catecholamines
- Glucagon
- Cortisol
- Growth hormone
What is the difference between a penetrating and a perforating injury
A perforating injury passes completely through the body cavity
Define a flail chest and a pseudo flail chest
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
What are the 3 main components of splenic vascularization? Where do they originate from?
What artery should be preserved when doing a splenecomty
- 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
What are the 4 abdominal muscles that constitute the abdominal wall? What layer holds sutures?
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
What are common locations of abdominal wall hernias
- Paracostal
- Inguinal
- Umbilical
- Scrotal
- Cranial pubic ligament rupture
- Ventral / subxiphoid
- Femoral
- Dorso-lateral
Describe some of the characteristics of the systemic response to severe injury
- 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
Name 3 bacterias commonly isolated from bite wounds
- Pasteurella spp
- Staph spp
- Strep spp
What are the 3 categories evaluated in the MGCS?
- Motor activity
- Brainstem reflexes
- Level of consciousness
What are the 2 components of trauma associated coagulopathy (TAC)?
- Endogenous coagulopathy with concurrent tissue hypoperfusion (acute coagulopathy pf trauma shock)
- Syndrome that occurs later and is exacerbated by resuscitation practices (resuscitation associated coagulopathy)
What are the 3 phases of healing?
- 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 - Prolific phase (begin day 4, lasts 2-3 wks):
- angiogenesis, granulation tissue, epithelialization - Maturation phase (day 17-20 up to years):
- wound contraction and remodeling of fibre bundles
- Scar is only 80% as strong as original tissue
Describe the pathophysiology of acute coagulopathy of trauma-shock
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
Briefly, how does platelet dysfunction occur in TAC?
Widespread release of ADP following tissue trauma may prematurely activate platelets leading to their exhaustion and retention into circulation.
List metabolic consequences of trauma
- Sympathoadrenal activation
- Neuroendocrine activation
- Hyperglycemia
- Hyperlactatemia
- Metabolic acidosis
- Hypothermia
- GI injury +/- translocation
- Systemic inflammation
- Acute traumatic coagulopathy
Why do patients develop hyperglycemias after trauma?
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
How are open fractures classified according to the Gustily-Anderson classification scheme?
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
What are indications for open reduction after traumatic joint luxation?
- 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
Wounds classification:
- 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
Name a few factors that can delay wound healing
- Poor O2 delivery (anemia, severe trauma, hypovolemia)
- Hypoproteinemia (<2g/L –> decreases fibrous tissue deposition)
- Chemotherapy/radiation therapy
- Diabetess, uremia, liver disease
- Steroids
What are the burn degrees?
- 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
How is the total surface body area (TBSA) burned estimated?
- 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
Why can hypovolemic shock occur in burn patients?
As a result of capillary thrombosis leading to leakage of plasma. Most dramatic loss of fluids and electrolytes occurs within the first 12 hours.
What volume of blood is held by a 22 gauze, 44 gauze, lap sponge
- 2*2 gauze holds 3.25 +/- 1.25 mL
- 4*4 gauze holds 10 +/- 2 mL
- lap sponge holds about 150 mL
A pneumomediastinum can lead to air in which other cavities?
- Pneumothorax
- SC emphysema
- Pneumoperitoneum
Explain the Macklin effect
Alveolus ruptures –> air dissects through peribronchovascular sheaths into pulmonary interstitium –> tracks along the perivascular space into the pulmonary hill and mediastinum –> pleural space
