Theory Flashcards
1
Q
Factors affecting accuracy of pulse oximetry
A
Peripheral perfusion (e.g. hypotension or obstruction) Methemoglobin Carboxyhemoglobin Anemia Hypothermia Readings <85% Excessive patient movement Intense ambient light Circulating dyes
2
Q
Rapid sequence induction
A
Preparation (suction, surgical alternative, PPV, position, 250ml preload, monitors, drugs, tubes, oxygen delivery system, laryngoscope)
Pre oxygenate (3-5min; 6 VC breaths)
Cricoid pressure
Induction agent (ketamine preferred)
Muscle relaxant (succinylcholine or rocuronium)
Intubate
Ventilate
3
Q
Contraindications to transurethral catheterization
A
Blood at urethral meatus Blood in scrotum Perineal ecchymosis High riding or non palpable prostate Pelvic fracture Vaginal or rectal injury
4
Q
Pulseless electrical activity on ECG
A
Cardiac tamponade
Tension pneumothorax
Severe hypotension
Cardiac rupture
5
Q
ECG changes of blunt cardiac injury
A
Unexplained sinus tachycardia Atrial fibrillation Premature ventricular contraction ST segment changes Bundle branch block (usually right)
Highest risk in the first 24 hours
6
Q
Difficult airway
A
Look for obvious signs - short neck, receding chin, overbite, cervical spine disease, maxillaofacial or mandibular trauma
Evaluate 3:3:2 rule
Assess Mallampati score
Obstruction e.g. tumour, abscess, epiglottis, trauma and inflammation, edema
Neck mobility (head extension)
Scars from previous trauma or surgery
7
Q
Confirming intubation placement
A
Visualization of tube entry to 22cm
Chest signs (expansion, improvement in sats, bilateral breath sounds) - right lower lobe NB
Condensation in tube
Auscultate epigastrium
Carbon dioxide monitor
Chest X-ray (does not exclude esophageal intubation)
Esophageal detector device
NB trachea vs. airway vs. esophagus
8
Q
Cardiac tamponade - classical presentation
A
Beck's triad: venous pressure elevation, arterial pressure fall, and muffled heart sounds Tachycardia Distended neck veins Hypotension resistant to fluid therapy Kussmaul's sign (rise in venous pressure on spontaneous inspiration) Pulsus paradoxus Elevated CVP Proximity injury
9
Q
Tension pneumothorax - classical presentation
A
Respiratory distress Subcutaneous emphysema Hyper resonance to percussion Absent breath sounds Distended neck veins Displaced trachea cardiac: displaced apex beat, non responsive hypotension, tachycardia Response to needle decompression
10
Q
Sites for rapid venous cutdown
A
Cubital fossa - basilica or cephalic vein
Radial aspect of wrist - cephalic vein
Deltopectoral groove - cephalic vein
Anteromedial aspect of ankle - long saphenous vein
Groin below ligament - long saphenous vein
11
Q
Massive hemothorax - classical presentation
A
Signs of shock
Absent breath sounds
Percussion dullness
12
Q
Pulsus paradoxus
- definition
- measurement
- differential
A
- difference in SBP > 10mmHg between inspiration and expiration (inspiration the lower one)
- deflate BP cuff slowly until Korotkoff heard during expiration. Slowly deflate further until sound also heard on inspiration. Measure difference in readings
- cardiac tamponade, constrictive pericarditis, severe OLD, restrictive cardiomyopathy, PTE, RVMI and shock
13
Q
Complications of blunt cardiac trauma
A
Complications: Myocardial contusion Cardiac chamber rupture Coronary artery dissection Coronary artery thrombosis Valvular disruption
Sequelae: Hypotension Dysrhymia Wall motion abnormalities Myocardial infarction
14
Q
Tracheobronchial tree injury - presentation
A
Hemoptysis Pneumomediastinum Pneumopericardium Persistent air leak from chest drain Persistent pneumothorax
15
Q
Blunt esophageal rupture
A
Abdominal blunt trauma with shock and pain disproportionate to injury
Left pneumothorax or hemothorax without rib fracture
Particulate matter in chest drain
Pneumomediastinum
16
Q
X-ray findings in diaphragm injuries
A
Blurring of the hemidiaphragm Hemothorax, pleural effusion Abnormal gas shadow obscuring hemidiaphragm Nasogastric tube in thoracic cavity Elevation of diaphragm Contralateral mediastinum shift
17
Q
Duodenal injuries - presentation
A
Blunt abdominal trauma
Bloody gastric aspirate
Retroperitoneal air
18
Q
Kehr’s sign
A
Pain referred to the left shoulder, suggestive of splenic rupture
19
Q
Hypotension in pelvic fracture - bleeding sources
A
Pelvic bones
Pelvic venous plexus
pelvic arterial injury
Extrapelvic sources
20
Q
X-ray signs of traumatic aortic disruption
A
Widened mediastinum (>8cm on erect film) Loss of aortic knuckle Obscuration of aortopulmonary window Widened paratracheal stripe Widened paraspinal interface Right tracheal deviation Depression of left main bronchus Elevation of right main bronchus Pleural or apical cap Left hemothorax Fracture of scapulae, 1st and 2nd ribs
21
Q
Differential diagnosis of widened mediastinum
A
Traumatic:
- aortic disruption
- pseudoaneurysm
- hematoma (e.g. sternal or vertebral fracture)
- collapsed lung
- disruption of other mediastinal vessels
Non-traumatic
- aneurysm
- right sided aorta
- cyst
- esophageal lesion
- tumour
- lymphoma
22
Q
Layers of the scalp
A
Skin Subcutaneous connective tissue Aponeurosis Loose connective tissue Periosteum
23
Q
Kernohan’s notch syndrome
A
Uncal herniation where ipsilateral corticospinal and contralateral oculomotor compression occurs, resulting in ipsilateral dilated pupil and hemiparesis (on the side opposite the herniation)
24
Q
Classification of brain injury
A
Mechanism
- blunt (high or low velocity)
- penetrating
Severity
- minor (GCS 13-15)
- moderate (GCS 9-12)
- severe (GCS 3-8)
Morphology
- skull fracture
- vault (linear vs stellate, depressed vs
nondepressed, open vs closed)
- base (with/without CSF leak, with/without
seventh nerve palsy
- intracranial lesions
- focal (epidural, subdural, intracerebral)
- diffuse (concussion, multiple contusion,
hypoxic/ischemic)
25
Glasgow coma scale
```
Eyes
4 - spontaneous
3 - to speech
2 - to pain
1 - none
```
```
Motor
6 - obeys commands
5 - localizes pain
4 - normal flexion(withdrawal)
3 - abnormal flexion (decorticate)
2 - extension (decerebrate)
1 - none
```
```
Verbal
5 - oriented
4 - confused conversation
3 - inappropriate words
2 - incomprehensible sounds
1 - none
```
26
Signs of base of skull fracture
```
Raccoon eyes
Battle sign
Otorrhoea
Rinorrhoea
Seventh nerve palsy
Eighth nerve palsy
Hemotympanum and blood in external auditory canal
```
27
Indications for CT scan in minor brain injury
```
Failure to reach GCS 15 in 2 hours
Clinically suspected skull fracture
Sign of basal skull fracture
More than 2 episodes of vomiting
>65 years
>5 minutes loss of consciousness
>30 minutes retrograde amnesia
Dangerous mechanism of injury
Focal neurological signs
Anticoagulation
Seizures
```
28
Diagnosis of brain death
```
Exclusion of effects of drugs and hypothermia
GCS 3
Non reactive pupils
Absent brainstem reflexes
Absent ventilatory drive on formal apnea test
Ancillary studies:
- EEG activity absent
- CBF absent
- ICP exceeds MAP for >1 hour
- cerebral angiography
Serial examination if uncertainty exists
```
29
Dermatomes
```
C5 - deltoid area
C6 - thumb
C7 - middle finger
C8 - little finger
T4 - nipple
T8 - xiphisternum
T10 - umbilicus
T12 - symphysis pubis
L4 - medial aspect of calf
L5 - web space between first and second toes
S3 - ischial tuberosity area
S4 and S5 - perianal region
```
30
Myotomes
```
C3-5 - diaphragm
C5 - deltoid
C6 - wrist extensors
C7 - elbow extensors (triceps)
C8 - finger flexion
T1 - small finger abductors
L2 - hip flexion
L3 and L4 - knee extension
L4, L5, S1 - knee flexion
L5 - dorsiflexion
S1 - plantarflexion
```
31
Jefferson fracture - what is it, and radiological sign
Burst fracture of atlas (C1)
| Lateral displacement of lateral masses of C1 on C2 on open mouth AP X-ray
32
Chance fracture
Transverse Thoracic vertebral fracture through the vertebral body caused by flexion about an axis anterior to the vertebral column
33
Signs of arterial injury
```
Pulse discrepancies
Coolness
Pallor
Paraesthesia
Motor abnormality
Abnormal ABI
Poor capillary refill
```
34
Tetanus prone wounds and prophylaxis
Age >6 hours
Stellate wound; avulsion (vs linear wound or abrasion)
Depth >1cm
Missile, crush, burn or frostbite (vs incised)
Signs of infection, devitalised tissue, contaminants, denervation or ischemia present
Prophylaxis only if <3 doses of toxoid previously received, or immune status unknown
- toxoid and immunoglobulin for tetanus prone wounds
- toxoid only otherwise
35
Signs and symptoms of compartment syndrome
```
Pain out of proportion to injury, that does not respond to treatment, and occurs on both passive and active movement
Paraesthesia
Decreased 2-point discrimination
Puffiness
Pressure
Decreased temperature
Pallor/ purple
```
36
Signs and symptoms of burn inhalation injury
```
Explosion with burns to head and torso
History of impair mentation and/or entrapment in burning environment
Head and neck burns
Singeing of eyebrows and nasal vibrissae
Carbon deposits and acute inflammatory changes in the oropharynx
Carbonaceous sputum
Hoarseness and strider
Tracheal tug
Respiratory distress
Elevated carboxyhemaglobin levels
```
37
Carbon monoxide poisoning
20-30% - nausea headache
30-40% - confusion
40-60% - coma
>60% - death
```
Half life:
250 minutes (room air)
40 minutes (100% oxygen)
```
38
Treatment of myoglobinuria
```
IV fluids
Electrolyte correction
Sodium bicarbonate
Osmotic diuretic
Maintain urine output 100ml/h
```
39
Transfer to burns unit
```
>10% BSA 2nd degree burns in children and elderly
>20% BSA 2nd degree burn in all ages
>5% BSA 3rd degree durn
Inhalation injury
Electrical burns
Chemical burns
Associated trauma
Pre-existing medical condition
Burns of the face, eyes, ears, hands, feet, genitals or perineum
Inadequately equipped to treat burns
Social reasons (e.g. Child abuse)
```
40
Common trauma in geriatrics
Falls
Motor or pedestrian vehicle collision
Burns
41
Considerations for trauma in the pregnant patient
```
Blunt or penetrating uterine trauma
Abruptio placentae
Rh isoimmunization
Amniotic fluid embolus
Rupture of membranes
```
42
Clinical syndromes following trauma
Systemic Inflammatory Response Syndrome:
- Pulse rate > 90 / min
- Respiratory rate >20 / min
- PACO2 < 32mmHg
- White cell count 12, or >10% immature band forms
- Temperature 38ºC
Sepsis: differentiated from SIRS only by evidence of infection
Severe sepsis: sepsis associated with one or more signs of organ dysfunction, hypoperfusion or hypotension
Multiple organ dysfunction: dysfunction of more than one organ in an acutely ill patient, requiring intervention to maintain homeostasis
43
Definitive care cutoff times
Tension pneumothorax (ventilated) - 5 minutes Class 4 shock - Less than 1 hour
Evacuation of intracranial haematoma - 4 hours Vascular repair - 6 hours (4 in Joburg)
Compartment syndrome - 2 hours Contaminated tissue - 8 hours
Compound fracture - 6 hours
Fixation of fracture of long bone or spine - 24-48 hours
44
Secondary brain injuries
Extra-cranial causes: shock, hypoxia, hyperglycaemia, hypoglycaemia
Intra-cranial causes: haematoma, brain oedema, infection, hydrocephalus
45
Causes of compartment syndrome
```
Vascular occlusion
Haematoma
Crush
Delayed reperfusion
MAST (PASG)
Extremity fracture
Local compression
Tight dressings e.g. POP
Circumferential burns
Extravasation of fluids
```
46
Types of nerve injuries
Neuropraxia: Functional paralysis of the nerve but no obvious anatomical injuries. The prognosis is excellent – recovery in 6 weeks to 3 months
Axonotmesis: Division of the nerve fibres (axons), intact neural sheath. Regeneration of the nerve fibres will occur. The prognosis is good
Neurotmesis: Complete or partial division of the neural sheath and nerve fibres. Needs surgical repair. Prognosis guarded
47
Signs of vascular injury
Hard signs of vascular injury:
- massive external bleeding
- absent or diminished pulses
- expanding or pulsatile haematoma
- palpable thrill or pulsation
- signs of distal ischemia (pain, pallor, pulselesness, paresthesiae, paralysis, coolness)
Hard signs demand immediate exploration. On-table angiogram is performed. Urgency is because the warm ischemic time of muscle is 6 hours (from injury)
Soft signs:
- proximity injury
- small non-pulsatile hematoma
- neurologic deficit
- history of arterial bleeding
The presence of peripheral pulses does not exclude proximal arterial injury (Collateral circulation)
Soft signs require differential pressure indices (Doppler of systolic BP) distal to injury. A differential pressure index of >10 % mandates angiogram, and predicts the need for surgical repair in > 90%. Soft signs in the presence of a differential pressure < 10% should be observed for at least 4 hours, and re-evaluated by differential pressures
48
High risk injuries for vascular damage
Posterior dislocation of the knee: popliteal artery
Displaced fracture distal femur: Superficial femoral artery
Anterior dislocation of shoulder: Axillary artery Supracondylar fracture of humerus: Brachial artery
49
Cricoid pressure
Backward, upward, rightward pressure
50
Signs of diaphragm rupture
May be asymptomatic (e.g. Ventilated patients)
Bowel sounds in chest, decreased air entry
Hemothorax
Perforation with ICD insertion
Left shoulder pain
CXR signs
Cardiopulmonary distress
51
Contraindications for DPL
Pregnancy (prefer FAST, or supraimibolidal DPL)
Previous laparotomy
Laparotomy planned
Children
Pelvic fracture (supraumbilical fracture)
52
Indications for non-operative management of abdominal injury
Hemodynamically stable patient
Solid organ injuries
Ongoing monitoring and evaluation in ICU or high care
Availability of surgical team and theatre
No more than two units of bleed required in 24 hours from admission
Evaluation and grading of injury with contrast CT
Baseline Hb, U&E, INR
Monitor Hb and ABG
Instability, bleeding or acute abdomen - laparotomy
53
Contraindications for non-operative management in abdominal injury
Evidence of hollow viscus injury
Hemodynamic instability
Inadequate circumstances for proper monitoring
Lack of surgical expertise
54
Diagnostic peritoneal lavage procedure
Empty bladder and stomach
Lignocaine anesthetic
Incision 1/3 below umbilicus
- closed: 0.5cm incision, insertion of peritoneal catheter using Seldinger technique
- open: 3cm incision, blunt dissection, insertion of peritoneal catheter under direct vision
Aspiration - 20ml of blood considered positive
Infuse 20ml/kg warmed RL, swish the patient
Drain lavage fluid - positive if:
- 10ml frank blood
- > 100 000 RBCs/mm^3 (blunt injury)
- > 10 000 RBCs/mm^3 (penetrating injury)
- > 500 WBCs/mm^3 (blunt injury)
- > 50 WBCs/mm^3 (blunt injury)
- raised amylase
55
Types of inhalation injury
Airway Injury Above the Larynx - Inhalation of hot gases resulting in thermal injury
Airway Injury Below the Larynx - Inhalation of products of combustion resulting in chemical injury
Systemic Intoxication –Absorption of compounds such as carbon monoxide or cyanide resulting in systemic effects
56
The three burn zones
Zone of coagulation - At the point of maximum damage. Irreversible tissue loss due to coagulation of the constituent proteins
Zone of stasis - Decreased tissue perfusion. This is potentially salvageable. The main aim of burns resuscitation is to increase tissue perfusion here and prevent any damage becoming irreversible. Additional insults such as prolonged hypotension, infection, or edema can convert this zone into an area of complete tissue loss
Zone of hyperemia - Tissue perfusion is increased. The tissue will invariably recover unless there is severe sepsis or prolonged hypoperfusion
57
Epidural vs subdural hematoma
Epidural does not cross suture lines, round semi moon shaped, no gyri and sulci
58
Physiological changes in burns
CVS
- increased capillary permeability (protein and fluid extravasation)
- decreased contractility
- hypotension and end organ hypoperfusion
Resp
- bronchoconstriction
- ARDS
Metabolic
- tachycardia
- increased cardiac output
- increased REE
- protein catabolism
- increased lipolysis (and fatty liver)
- hyperthermia
Immune system
- decreased function of humoral and cellular immunity
59
Diagnosis of sepsis
```
Temperature >38.5 or 30
Blood glucose > 14 mg/dL
WCC > 15000 or < 5000
Platelets < 100 000
Paralytic ileus (gastric residual >200ml)
Wound biopsy > 10^5 organisms/g
Positive blood culture
```
60
Benefits of biological dressing in burns
```
Adheres to wound surface
Decreases pain
Decreases protein and fluid loss
Increases epithelialization
Decreases CFUs
```
61
Big 5 bleeders
```
Thoracic
Abdominal
External
Pelvis
Long bones
```
62
Indications for CT in head injury
GCS 12 or less
Deterioration of the level of consciousness
convulsions
Severe headache
Lack of improvement of a depressed level of consciousness
Lateralizing neurological signs
63
Secondary brain injury - causes
Extracranial
- hypotension
- hypoxia
- hypoglycemia
- hyperglycemia
- hyperthermia
Intracranial
- cerebral edema
- hematoma
- hydrocephalus
- infection
64
Chronic complications of head injury
```
Post concussion syndrome
Chronic subdural hematoma
Hydrocephalus
Post traumatic epilepsy
Late CSF leaks
Bain atrophy
Carotid-cavernous fistula
Intracranial aneurysm
```
65
Calculate % mortality in burns
Age + %BSA
66
Systemic response to shock
Neuroendocrine
- catecholamines
- ADH
- mineralocorticoids
- glucocorticoids
- insulin
- glucagon
Immune response
- cytokine release
- cellular and humoral response
Cellular activation
- platelets
- endothelial
- leukocytes
67
Pathophysiological effects of shock
```
Glucose intolerance
Vasoconstriction
Salt and water retention
Capillary leak
Coagulopathy
Anaerobic metabolism
Organ dysfunction
```
68
Causes of occult hypotension
```
Hypothermia
Acidosis
Coagulopathy
Continued bleeding
Leaky capillary syndrome
```
69
Treatment goals in shock
```
SBP > 90
Urine output > 1ml/kg/hour
Pulse < 120
Lactate < 2.5
Base deficit < 6
Temperature > 36
Pco2 > 100
Normal coagulation
```
70
Classifications of shock, and causes in trauma
```
Hypovolemic - hemorrhage
Cardiogenic
- tension PTX
- cardiac tamponade
- blunt cardiac injury
- myocardial infarct
- air embolus
Neurogenic - spinal cord injury
Septic - delayed presentation (>6 hours)
```
71
Mortality in subdural hematoma
< 4 hours to surgery - 30%
| > 4 hours to surgery - 85%
72
When to intubate pulmonary contusion
```
PO2/ FIO2 < 200
RR > 30/min
O2 saturation < 95 on polymask
PCO2 > 45
Use of respiratory muscles with FiO2 65%
```
73
Difficult BMV ventilation
```
Mask seal (facial anatomical deformities, beards)
Obesity
Age > 55 years
No teeth
Snores or stiff
```
74
Difficult cricothyroidotomy
```
Surgery/ disrupted airway
Hematoma or infection
Obesity/ access problem
Radiation
Tumour
```
75
Difficult extraglottic deviced
Restricted mouth opening
Upper airway obstruction at the larynx or below
Disrupted or distorted anatomy
Stiff lungs or cervical spine
76
Myotomes
```
–C5(deltoid)
–C6(wrist extension)
–C7(elbow extension)
–C8(middle finger)
–T1(small finger)
–L2(hip flexion)
–L3(knee extension)
–L5(long toe extension)
```
77
Dermatomes
```
–C5(detoid)
–C7(middle finger)
–T4(nipple)
–T10(umbilicus)
–L1(medial thigh)
–L4(medial leg)
–S1(lateral foot)
–S4/5(perianal)
```
