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