Critical Care MRCS part B Flashcards
organic compound containing arrangement of 4 cycloalkane rings joined together - describes what substance?
Steroids
which factors increase aldosterone production?
Angiotensin II (via RAA)
reduced Na+
Increased K+
sodium reabsorption and potassium excretion at the distal convoluted tubule andcollecting duct - describes what steroid?
Aldosterone
aldosterone leads to water retention by what mechanism?
Sodium reabsorption
Excretion of potassium causes what effect on acid base balance?
Metabolic alkalosis
glucocorticoids have their hyperglycaemic effect by what mechanisms?
Antagonise insulin
Stimulate gluconeogenesis
corticotrophic releasing hormone is produced where?
Hypothalamus
ACTH is produced where?
Anterior pituitary
what hormones are produced by the anterior pituitary?
ACTH GH Prolactin TSH FSH, LH
what hormones are produced by the posterior pituitary?
ADH
Oxytocin
what are the 4 main features of addisonian crisis?
Abdominal pain
Nausea/Vomiting
Unexplained Shock
Hyper/Hypothermia
when does addisonian crisis occur?
Acute reduction in circulating steroids
what is the specific management of addisonian crisis?
IV Fluids
IV steroids
Adjustment and replacement of electrolytes
in addison’s disease what happens to the sodium and potassium levels?
Low Na+
High K+
what does ASA 6 correspond to?
A declared brain dead person whose organs are being removed for donor purposes
what does the LEMON assessment stand for when assessing for signs of difficult intubation?
L = Look E = Evaluate M = Mallampati score O = Obstruction N = Neck mobility
what does the 3-3-2 rule stand for when allowing alignment for easier intubation?
Incisors - 3 fingers between
Hyoid + Chin - 3 fingers between
Thyroid notch + floor of mouth - 2 finger between
what are the admission criteria to HDU?
HDU - 2:1 nursing
Close/invasive monitoring of unstable patient
Single Organ support
what are the admission criteria to ITU?
ITU = 1:1 nursing
Mechanical support of organ function
Multi-organ support
Reversible condition
what is the definition of shock?
Inadequate tissue perfusion to meet metabolic requirements
what type of shock can occur after spinal anaesthesia?
Distributive shock
what specific examination would you perform in a patient after a spinal anaesthetic?
Neurological status of legs
blood pressure is equal to what?
BP = CO x SVR
what are the contents of a tracheostomy box?
Tracheostomy tube of same size Tracheostomy tube one size smaller Spare inner tubes Resuscitation bag and mask Suction and suction catheters 0.9% NaCL + syringe to moisten plug Scissors + tape
what are the airway indications for a tracheostomy tube?
Upper Airway Obstruction eg. trauma, oedema
Prophylaxis eg. H+N surgery
Emergency Procedure
what are the breathing indications for a tracheostomy tube?
Prolonged Ventilation eg. NM disorders
Facilitation of Ventilator weaning
More efficient Secretion Management + pulmonary toilet
what are the indications for renal replacement therapy?
Anuria/Oliguria Hyperkalaemia K+ >6.5 Acidaemia ph <7.1 Fluid overload (refractory) uraemic complications (encephalopathy, pericarditis) drug overdose temp control
which diseases are blood transfusions screened for in the uk?
Hep B Hep C HIV Syphilis CMV HTLV - in 1st time donors
what dose of steroid is given at induction to pts at risk of adrenal insufficiency?
Hydrocortisone 100mg IV
what regular daily dose of prednisolone puts pts at risk of adrenal insufficiency?
Pred 5mg or over
for how long can RBC be stored and at what temp?
35 days, 2-6 Celsius
for how long can platelets be stored and at what temp?
5 days, 20-24 Celsius (room temp)
for how long can FFP/Cryoprecipitate be stored and at what temp?
1 year, -30 celsius
what are the constituents of FFP?
Albumin All clotting factors Complement Fibrinogen vWF
what are the constituents of Cryoprecipitate?
Factor VIII
Factor XIII
Fibrinogen
vWF
what electrolyte abnormalities can occur after blood transfusion?
Hyperkalaemia
Hypocalcaemia (due to citrate binding calcium)
what biochemical abnormality commonly occurs in prolonged and persistent vomiting?
Hypokalaemic, hypochloraemic metabolic alkalosis
what are the clinical features of hypokalaemia?
Mild: muscle weakness, cramps, myalgia
Severe: paralysis, hyporeflexia
what are the ECG findings in hypokalaemia?
Flat/inverted T waves
ST depression
U waves
Prolonged PR interval
what is the max speed limit of K+ replacement using a peripheral line?
10mmol/hr
what is the most common level of C spine fracture?
C5
the balthazar scoring system for pancreatitis uses which imaging modality?
CT scan
what does the glasgow criteria stand for in pancreatitis staging?
P - PaO2 <8 A - Age >55y N - Neuts >15 C - Calcium <2 R - Renal function (urea >16) E- Enzymes LDH >600, AST >1000 A - Albumin <32 S - Sugar glucose >10
Why does hypocalcaemia occur in pancreatitis?
Saponification of omental fat by pancreatic enzymes. Free fatty acids released from breakdown of omental fat by pancreatic enzymes - chelate calcium
which cells produce insulin?
B cells of islets of langerhans
what cells produce somastatin?
Delta cells of islets of langerhans
what cells produce glucagon?
Alpha cells of islets of langerahns
what is the henderson hasselback equation?
CO2 + H20 = H2CO3 = HCO3 + H+
what is a normal anion gap?
8-16
what is the equation to calculate anion gap?
(Na+ + K+) - (Cl- + HCO3-)
what are the most important blood buffers?
Bicarbonate and haemoglobin
what are the ECG findings in hyperkalaemia?
Tall tented waves Shortened QT ST depression Absent P waves Progressive QRS widening
what is the definition of oliguria?
<0.5ml/kg/hr urine output
in the classification of acute limb ischaemia at which category is muscle paralysis noted?
Partial muscle paralysis stage IIb
in the classification of acute limb ischaemia at which category is sensory loss noted?
Partial sensory loss from IIa
what are the risks of an embolectomy?
Intimal damage Arterial puncture Pseudoaneurysm formation Amputation if ischaemia is irreversible Damage to femoral vein/nerve
what are the chest x ray findings in ARDS?
Diffuse bilateral pulmonary infiltrates
what is the definition of ARDS?
Clinical syndrome consisting of acute respiratory failue, non cardiogenic pulmonary oedema leading to hypoxaemia + decreased lung compliance that is refractory to oxygen therapy
What are the 3 key characteristics of ARDS?
- Diffuse bilateral pulmonary infiltrates on CXR
- Normal pulmonary artery wedge pressre (PaWP <18mmHg)
- PaO2/FiO2 ratio <26.6Kpa
how does mechanical ventilation aid treatment in ARDS?
Aid oxygenation, reduce work of breathing, improve CO2 clearance
how does prone ventilation improve ARDS?
Improves V/Q mismatch
Minimises basal atelectasis
Redistributes secretions
where is a tracheostomy commonly performed?
2nd - 5th tracheal ring
where is a crichothyroidotomy performed?
Through cricothyroid membrance between cricoid cartilage and thyroid cartilage
what is the definition of pain?
Unpleasant sensory + emotional experience associated with actual or potential tissue damage
what can occur as a complication of pain?
Increase sympathetic tone Atelectasis + LRTI Reduced mobility Chronic pain Imparied sleep negative psychological effects
what is another name for a pain receptor?
Nociceptor
what sensation is carried by myelinated A-delta fibres?
Quick sharp localised pain
Fast transmitted
What sensation is carried by the unmyelinated C fibres?
Dull, deep throbbing pain
Poorly localised
Slow conducting
what are the risk factors for chronic post surgical pain?
Pre op pain longer duration of surgery ADjuvant chemo/radiotherapy Intraoperative nerve injury Psychological factors Severe post op pain
what is the definition of massive transfusion?
Replacement of >1 blood volume in 24 hrs
>50% blood volume in 4 hours
what are the pharamcological alternatives to blood transfusion?
Iron tablet EPO TXA Recombinant FVIIIa Cell saver device - autologous transfusion
what are the reversible causes of apnoea (non brain stem)?
C-spine injury
Hypoxia
Neuromuscular weakness
what is parklands formaula?
Fluid requirement (ml) = 2-4% burn x weight (kg)
over what time is fluid resuscitation given in burns?
Half given in 1st 8 hours from burn
Half given subseuqent 16 hours from burn
what are the immeadiate complications of central line insertion?
Haemorrhage
Pneumothorax
R atrial perforation
what are the early complications of central line insertion?
Bloackage
Cyclothorax (L side)
pseudoaneurysm
what are the late complications of central line insertion?
Infection Thrombosis Catheter failure Vascular erosion Vascular stenosis
what does a CXR performed after insertion of a central line check for?
- Position of radioopaque tip (should be in SVC just uperior to its insertion into R atrium)
- Pneumothorax
what is a normal tissue pressure?
0-10mmHg
what delta pressure is suggestive of compartment syndrome?
<30mmHg
how is delta pressure calculated?
Diastolic BP - intracompartment pressure
where is the incision placed to decompress the anterior and lateral compartments of the leg?
Full length anterolateral incision, 2 fingerbreadths lateral to subcutaneous border of tibia, from just above ankle to tibial tuberosity
where is the incision placed to decompress the posterior compartments of the leg?
Full length incision 2 fingerbreadths medial to subcutaneous border of tibia from tibial tuberosity to 5cm above medial malleolus
what is the underlying pathology behind rhabdomyolysis causing renal failure?
Acute tubular necrosis
nephrotoxic effect of myoglobin on renal tubules
what is myoglobin?
Oxygen binding protein found in muscle
what is gamma glutamyltransferase and where is it found?
In hepatocytes and epithelium of small bile ducts
Aside from the liver, where is ALP found in the body?
Bone and placental tissur
what enzyme is responsible for the conjugation of bile?
Glucoronyl transferase - conjugates bilirubin with glucuronic acid. It is then water soluble and extrected in bile
what bacteria are responsible for metabolising conjugated bilirubin?
Colonic bacteria - form stercobilinigen which is further oxidised into stercobilin + excreted in faeces
what is the definition of spinal shock?
Flaccid paralysis, areflexia, loss of sensation associated with spinal cord trauma
what is the definition of neurogenic shock?
Loss of sympathetic outflow (and therefore unopposed parasympathetic outflow) due to spinal cord injury.Presents with bradycadia, hypotension due to decreased peripheral vascular resistance
which nerve roots are tested for in the bulbocavernosus reflex?
S2,3,4
absence of the bulbocavernosus reflex is indicative of what?
Spinal shock
what is the definition of complete spinal cord injury?
Occurs in the presence of an intact bulbocavernosus reflex where there is no sensory or motor function below the level of injury
what is the definition of incomplete spinal cord injury?
Occurs in presence of an intact bulbocavernosus reflex where there is some neurological function below the level of injury
autonomic dysregulation can occur in patients with a spinal cord injury above what level?
T6
Sympathetic response below level
Parasympathetic response above level
what operation is curative in UC?
Panproctocolectomy
what are the main medical management options in IBD?
Steroids Aminosalicylates Thiopurines Methotrexate Biologic agents
in which type of IBD is mesenteric fat wrapping seen?
Crohns
in which type of IBD does bowel wall thickening occur?
Crohns
which internal jugular vein has a straighter and more direct route to the SVC and R ventricle?
Right internal jugular
NICE guidelines suggest conservative management with antibiotics for diverticular abscesses of what size?
<3cm
long standing use of what drugs increase risk of diverticular disease?
Opiates
which bones make up the pterion of the skull?
Frontal
temporal
sphenoid
Parietal
