Theory Flashcards
Factors affecting accuracy of pulse oximetry
Peripheral perfusion (e.g. hypotension or obstruction) Methemoglobin Carboxyhemoglobin Anemia Hypothermia Readings <85% Excessive patient movement Intense ambient light Circulating dyes
Rapid sequence induction
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
Contraindications to transurethral catheterization
Blood at urethral meatus Blood in scrotum Perineal ecchymosis High riding or non palpable prostate Pelvic fracture Vaginal or rectal injury
Pulseless electrical activity on ECG
Cardiac tamponade
Tension pneumothorax
Severe hypotension
Cardiac rupture
ECG changes of blunt cardiac injury
Unexplained sinus tachycardia Atrial fibrillation Premature ventricular contraction ST segment changes Bundle branch block (usually right)
Highest risk in the first 24 hours
Difficult airway
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
Confirming intubation placement
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
Cardiac tamponade - classical presentation
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
Tension pneumothorax - classical presentation
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
Sites for rapid venous cutdown
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
Massive hemothorax - classical presentation
Signs of shock
Absent breath sounds
Percussion dullness
Pulsus paradoxus
- definition
- measurement
- differential
- 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
Complications of blunt cardiac trauma
Complications: Myocardial contusion Cardiac chamber rupture Coronary artery dissection Coronary artery thrombosis Valvular disruption
Sequelae: Hypotension Dysrhymia Wall motion abnormalities Myocardial infarction
Tracheobronchial tree injury - presentation
Hemoptysis Pneumomediastinum Pneumopericardium Persistent air leak from chest drain Persistent pneumothorax
Blunt esophageal rupture
Abdominal blunt trauma with shock and pain disproportionate to injury
Left pneumothorax or hemothorax without rib fracture
Particulate matter in chest drain
Pneumomediastinum
X-ray findings in diaphragm injuries
Blurring of the hemidiaphragm Hemothorax, pleural effusion Abnormal gas shadow obscuring hemidiaphragm Nasogastric tube in thoracic cavity Elevation of diaphragm Contralateral mediastinum shift
Duodenal injuries - presentation
Blunt abdominal trauma
Bloody gastric aspirate
Retroperitoneal air
Kehr’s sign
Pain referred to the left shoulder, suggestive of splenic rupture
Hypotension in pelvic fracture - bleeding sources
Pelvic bones
Pelvic venous plexus
pelvic arterial injury
Extrapelvic sources
X-ray signs of traumatic aortic disruption
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
Differential diagnosis of widened mediastinum
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
Layers of the scalp
Skin Subcutaneous connective tissue Aponeurosis Loose connective tissue Periosteum
Kernohan’s notch syndrome
Uncal herniation where ipsilateral corticospinal and contralateral oculomotor compression occurs, resulting in ipsilateral dilated pupil and hemiparesis (on the side opposite the herniation)
Classification of brain injury
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)
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
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
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
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
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
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
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
Chance fracture
Transverse Thoracic vertebral fracture through the vertebral body caused by flexion about an axis anterior to the vertebral column
Signs of arterial injury
Pulse discrepancies Coolness Pallor Paraesthesia Motor abnormality Abnormal ABI Poor capillary refill
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
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
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
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)
Treatment of myoglobinuria
IV fluids Electrolyte correction Sodium bicarbonate Osmotic diuretic Maintain urine output 100ml/h
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)
Common trauma in geriatrics
Falls
Motor or pedestrian vehicle collision
Burns
Considerations for trauma in the pregnant patient
Blunt or penetrating uterine trauma Abruptio placentae Rh isoimmunization Amniotic fluid embolus Rupture of membranes
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
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
Secondary brain injuries
Extra-cranial causes: shock, hypoxia, hyperglycaemia, hypoglycaemia
Intra-cranial causes: haematoma, brain oedema, infection, hydrocephalus
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
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
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
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
Cricoid pressure
Backward, upward, rightward pressure
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
Contraindications for DPL
Pregnancy (prefer FAST, or supraimibolidal DPL)
Previous laparotomy
Laparotomy planned
Children
Pelvic fracture (supraumbilical fracture)
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
Contraindications for non-operative management in abdominal injury
Evidence of hollow viscus injury
Hemodynamic instability
Inadequate circumstances for proper monitoring
Lack of surgical expertise
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
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
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
Epidural vs subdural hematoma
Epidural does not cross suture lines, round semi moon shaped, no gyri and sulci
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
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
Benefits of biological dressing in burns
Adheres to wound surface Decreases pain Decreases protein and fluid loss Increases epithelialization Decreases CFUs
Big 5 bleeders
Thoracic Abdominal External Pelvis Long bones
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
Secondary brain injury - causes
Extracranial
- hypotension
- hypoxia
- hypoglycemia
- hyperglycemia
- hyperthermia
Intracranial
- cerebral edema
- hematoma
- hydrocephalus
- infection
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
Calculate % mortality in burns
Age + %BSA
Systemic response to shock
Neuroendocrine
- catecholamines
- ADH
- mineralocorticoids
- glucocorticoids
- insulin
- glucagon
Immune response
- cytokine release
- cellular and humoral response
Cellular activation
- platelets
- endothelial
- leukocytes
Pathophysiological effects of shock
Glucose intolerance Vasoconstriction Salt and water retention Capillary leak Coagulopathy Anaerobic metabolism Organ dysfunction
Causes of occult hypotension
Hypothermia Acidosis Coagulopathy Continued bleeding Leaky capillary syndrome
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
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)
Mortality in subdural hematoma
< 4 hours to surgery - 30%
> 4 hours to surgery - 85%
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%
Difficult BMV ventilation
Mask seal (facial anatomical deformities, beards) Obesity Age > 55 years No teeth Snores or stiff
Difficult cricothyroidotomy
Surgery/ disrupted airway Hematoma or infection Obesity/ access problem Radiation Tumour
Difficult extraglottic deviced
Restricted mouth opening
Upper airway obstruction at the larynx or below
Disrupted or distorted anatomy
Stiff lungs or cervical spine
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)
Dermatomes
–C5(detoid) –C7(middle finger) –T4(nipple) –T10(umbilicus) –L1(medial thigh) –L4(medial leg) –S1(lateral foot) –S4/5(perianal)
