Surgical and critical care deck Flashcards
What is the Glasgow scale of pancreatitis
PANCREAS
PaO2 <7.9
Age >55
Neutrophils (really WCC) >15
Calcium <2.0
Renal function: urea >16mmol/L
Enzymes: LDH >600 IU/L
Albumin <32 g/L
Sugar >10mmol
What are the causes of pancreatitis
I GET SMASHED
Idiopathic
Gallstones
Ethanol
Trauma
Steroids
Mumps/malignancy
Autoimmune disease
Scorpion sting
Hypertriglyceridemia/Hypercalcaemia
ERCP (endoscopic retrograde cholangiopancreatography)
Drugs: commonly azathioprine, thiazides, septrin, tetracyclines
What is the reason for hypocalcaemia in patients with pancreatitis
Saponification of fat from the enzymes released. Free fatty acids that are released chelate calcium.
What is the reason for hyperglycemia in patients with pancreatitis?
Destruction by enzymes of insulin-producing islet cells
What are the complications of pancreatitis
Early: DIC, ARDS and pleural effusions, metabolic, paralytic ileus, renal failure, portal vein thrombus, death
Late: Diabetes and malnutrition
Local: Haemorrhage, pseudocysts, necrosis, ascites
What equation controls acid base balance
Henderson hasselbach equation. Largely, carbonic anhydrase acts as a buffer
How is aCO2 carried in the body
Dissolved, buffered in water as carbonic anhydrase and attached to proteins (eg haemoglobin)
What is the chloride shift
In peripheral tissues, the CO2 enters RBCs and is converted to HCO3 via carbonic anhydrase and then leaves the RBC
In the lungs, the reverse occurs, and HCO3 enters RBC and CL leaves allowing HCO3 to be converted to CO2 and expelled. The ‘chloride shift’ allows for this to happen
What are the causes of respiratory alkalosis
Anxiety
Pain
High altitude
Asthma
Salicylate poisoning
What are the causes of respiratory acidosis
Flail chest
lung contusion
Pneumonia
ARDS
Metabolic alkalosis
Vomiting
Renal loss of H+
Diuretics
Definition of an aneurysm
Local dilatation of blood vessels to more than 1.5 times its size
How are aneurysms classified
Aetiology: Inflammatory, infective, congenital, tru or false
Site: Thoracic, abdominal, intracranial
Size: giant vs berry
shape: Fusiform, saccular
When would you consider an infrarenal aorta aneurysmal
normal diameter is 2cm so anything above 3
When would you consider repair of AAA
Above 5.5 or above 4 and has increase in size by >1cm over the past year
Monitoring for AAA
Below 3 cm patient can be discharged
3 - 4.4: Monitor annually
4.5 - 5.4: Monitor 3 monthly
>5.5cm should be referred to vascular for repair
What is the mortality with AAA
Elective 3-5%
Emergency: 50% mortality rate
50% of ruptured AAA don’t arrive the hospital
What specific complications of EVAR
Intraoperatively, there can be a rupture as well as an endoleak
Post op: Infection, MI, renal failure, mesenteric ischemia,
Aortic dissection classification
Stanford A for ascending and B for descending
A often requires surgery whereas B can be managed with medical therapy to prevent extension of aneurysm
What are the complications of open AAA repair
Immediate: Haemorrhage, distal limb thrombosis and embolisation
Early: Spinal cord ischaemia, acute mesenteric and renal ischemia, MI, CVA
Late: False aneurysm, graft infection, mycotic aneurysms and aorto-duodenal fistulas
FACT
In BC, the aerobic bottle goes first and then the anaerobic
6 hours of a painful and cool leg, what are the possible differentials
ALI, CLI, arterial dissection, traumatic disruption of blood flow, neurological compromise
What are the classifications of ALI
Bascially the muscles should be the last to go and if muscle weakness or paralysis then the limb might need to be amputated
What is reperfusion injury
Reperfusion with blood distal to the site of obstruction. It is complex but involves inflammation and the generation of oxygen free radicals
What layers do you go through to make a trachy
Skin, sub-cut fat, platysma, investing fascia, strap, pre tracheal fascia, thyroid isthmus, trachea
Define pain
It is an unpleasant sensory stimulus to actual or potential tissue damage. A pain receptor is called a nociceptor
What is allodynia
Sensation of pain from a normally non painful stimuli
What is neuropathic pain
Pain caused by damage to the pain-signalling pathway
It can occur in the form of stinging or burning in diabetes or nerve damage or impingement like in sciatica for example
FACT
Patients with a CHADVASC2 score of more than 2 should be offered anticoagulation. Orbit score assess the risk of bleeding whereas CHADVASC2 score assess the risk of stroke
What is the shelf life of packed RBC
35 days if stored in a freezer appropriately
Define a massive transfusion
Blood volume grater than the patients circulating volume given within 24 hours or >50% of circulating blood volume given in a 4 hour period
What are the possible options for transfusion for jehovas witness
Medically correct low iron or folate and or B12, EPO, TXA
IV fluids to increase circulatory volume and maintain CO
Haemostasis and cell salvage in theatre
Explain the medical management of IBD
Steroids: USe sparingly
Aminosalicylates: Mainly used in order to maintain remission
Thiopurines: Aza and typically useful for remission as well as maintenance
Methotrexate
Biologic: Infliximab and TNF alpha inhibitors
What is the Charcot triad
Jaundice
RUQ pain
Pyrexia
add low BP and tachycardia to this and we have the raynaulds pentad
Explain LFTs
ALT and AST are produced by the liver but ALT is more sensitive as AST can be produced in many other places
ALP is produced outside the liver in the bile duct and hence ALP > ALT/AST can indicate a cholestatic picture
Where else is ALP found
Pagets disease and pregnancy
Where is GGT located
In hepatocytes
How is bilirubin formed
RBCs are broked down at the end of their life and haem is converted to bilirubin and bilivirdin.
Bilirubin then conjugates in the liver and is mixed into bile
What is the fate of conjugated bilirubin
Is digested by bacteria in the gut to form stercobilinogen which is further oxidised to stercobilin and this gives the faeces their brown colour
Small amount of stercobilinogen is excreted in the urine as urobilinogen which undergoes further oxidization to form urobilin and this gives urine its yellow colour
What are some of the resons for ET tube insertion
Burn/inhalation injury
Trauma to the neck
MAX FAX trauma
<GCS
Airway obstruction/ oedema
ITU for ventilation
What are the criteria for non operative management of extradural haematoma
<30 cm size
<15mm thick
<5mm midline shift
GCS >8 and without focal neurology
Define the Monroe kelly doctrine
the contents of the cranium – which are the brain parenchyma, blood, and cerebrospinal fluid (CSF) – are constant/fixed
An increase in one must mean a reduction in one of the others and vice versa
What is the cushings reflex
HTN, Brady and chaine stokes breathing as response to raised ICP due to mixed symp and parasymp responses
What can distort pulse oximeter readings
Fake nails
CO poisoning can overestimate it
Poor perfusion
Jaundice will underestimate the true reading
What are the risks of using colloids
Anaphylaxis
Reduced platelet agg and dysfunction
At what point do you assess for brainstem arreflexia
evidence of irreversible brain injury on scan and clinical presentation
It should only be done when reversible causes of coma and/or apnoea are excluded
What are the criteria for brainstem death
Fixed pupils
No corneal, oculovestibular reflexes
No bronchial stimulation cough reflex with suction catheter
No response to supraorbital pressure
How do you perform the apnoea test
Adequately pre-oxygenate the patient
Hypoventilates until PCO2 >6 and PaO2 <7.4 on ABG
Disconnect from the ventilator and maintain oxygenation via C circuit of endotracheal tube for 5 mins. Then repeat ABG. If 0.5 kPa more pCO2 then apnoea confirmed
What is the absolute contraindication to organ donation
HIV or CJD illness
Organs may not be donated in sepsis, malignancy, dysfunction, extended periods of hypoxia
What are some of the causes of pseudohyponatraemia
taking blood from the drip am
multiple myeloma
What are the signs and symptoms of hyponatraemia
Confusion, seizures, headache, reduced GCS
What are the stages of hypotension
What are partial thickness burns
Burns that have epidermis and dermal involvement
Superficial dermal when the upper layer of dermis are involved and deep dermal when all of dermis is involved
What should you check for in a CXR post CV insertions
Pneumothorax
Position of the radio-opaque catheter TIP in the SVC just superior to its insertion into the right atrium
What are the layers that you go through to insert a subclavian vein catheter
Skin
Subcutaneous fat and fascia
Pec major
subclavius muscle
Subclavian vein
What are the guidlines of drainage of a diverticular abscess
More than 3 cm requires drainage
It can be perc, lap or open depending on the location and severity of the abscess
What is the hinchey classification of diverticular abscess
0 - mild with no abscess
1 - Pericolic inflammation or abscess formation
2 - pelvic, distal intra abdo or retroperitoneal
3 - purulent peritonitis
4 - faecal peritonitis
1 and 2 can be managed conservatively or drained perc
3 and 4 need emergency surgery
What are the key characteristics of ARDS
Bilateral pulmonary infiltrates on chest radiograph
What is the prognosis of ARDS
normally 30-60% and with sepsis it can be as high as 90%
How would you deal with a blocked CVP line
Assess the patient and line and check for any bends or kinks
Re-check the procedural note as well as the XR
Ask the patient to cough as this changes IT pressure
urokinase?
What is DIC
It is a form of pathological consumptive coagulopathy. Prolonged PT and APTT with thrombocytopenia, low fibrinogen and anaemia. Causes the clotting cascade to aggressively activate and can then lead to blood loss
What is the most common cervical vertebrae to be injured
C5
What is the difference between a spinal shock and a neurogenic shock
Neurogenic shock is a disruption of sympathetic outflow that causes hypotension and bradycardia
Spinal shock is causes flaccid paralysis, areflexia and parasthesia associated with spinal cord injury
What is a hangman fracture
Fracture of both pedicle of cervical vertebrae. CT angio should be done as well in this case to check for vertebral artery injury
Bulbocavernous reflex
Feeling internal and external anal sphincter function by tugging on a foley catheter as well as pressing on the glans of the penis in a male or the clitoris in a female
What is autonomic dysreflexia
Injury at the level of T6
Below it there is sympathetic stimulation that leads to vasoconstriction and hypertension
Above is parasympathetic that leads to vasodilation and hypotension
This can cause CVA, arrhythmia, cardiac arrest and respiratory arrest
What is myoglobin
It is the oxygen-binding protein that is found in muscles. It is released during rhabdomyolysis
A higher proportion of myoglobin means that muscles can continue to function without O2 for longer. This becomes especially important in deep sea diving creatures that have to operate at low PaO2 atm
How would you identify a hypovolaemic patient
Pale, clammy, cool peripheries, Sinus tachycardia and tachypnoea
Dry mucous membranes
<2s cap refill time
Spinal vs epidural
Epidural is only for certain segments eg: inserted at t3 would have an effect on T4 and T5 nerve roots
Spinal will block everything below the level it has inserted
What are the risks of a high thoracic block
Blocks sympathetic stimulus to the heart
Dermatomes and myotomes of that region affected
Affects intercostal muscles and hence can affect respiration
What are some of the signs of local anaesthetic toxicity
Hypertension and tachy early and then hypotension, arrhythmia and arrest
Seizures
Peri-oral numbness or tingling
Fasciculations and tremors
What is capacitance
It is the ability to hold charge
What are the different fistula types based on output
Low <200mls per day
Medium 200-500mls per day
High <500mls per day
How much should a normal adult urinate per day
0.5mls/kg/hr
IV fluids as maintenance
25–30 ml/kg/day + any losses from stoma or fistula
When would you consider renal replacement therapy
Anuria/ oliguria
Hyperkalaemia
Severe acidosis
Fluid overload
Uremic complications
Drug overdose
Temperature control
What type of immunosuppressant drugs are there
Glucocorticosteroids
Alkylating agents like cyclophosphamide
Methotrexate, aza and tacro ciclo are all antimetabolites
Biologics
What is bloods tested for normally before a transfusion
Hep B and C
HIV
Syphilis
Human T lymphotropic virus (first time donors only)
How long can you store blood products and at what temperatures
RBC/ 35 days/ 2-6C
Plt/ 5 days/ 20-24C
FFP and cryo/ 1 year/ -30c
What are the contents of FFP
Albumin, all clotting factors, complement, vWF and fibrinogen
What are the contents of cryoprecipitate
Factor 8, 13, fibrinogen and vWF
What is the definition of hypothermia
Core body temp less than 36 degrees
What is a J wave and when does it happen
It happens in hypothermia and is also known as the Osbourne wave. It is a pathological upward deflection between the QRS complex and T wave
What are the complications of hypothermia
Reduction in CO and increase in Hb affinity to O2 leading to decreased tissue perfusion
Decreased drug metabolism
Reduced clotting function and hence increase bleeding
What are the NICE guidelines for perioperative hypothermia
Bear hugger and warm IVI and irrigation
Patient should not leave recovery unless temp is above 36C
What is normal body water distribution
1/3rd is extracellular and 2/3rd is intracellular
Out of the 1/3rd extracellular, 25% is intravascular and 75% is interstitial
This is hence 5% of the total body water that is intravascular or 250mls
How will 1L of crystalloid be distributed in the body
25% intravascular and 75% interstitial
This is contrary to blood, that remains intravascular
Why is 5% dextrose not used for resus
Rapidly lost from the extravascular compartment as glucose is taken up by the cells
2/3rd goes into the intracellular space and 1/3rd goes into the extracellular space.
Of the extracellular, only 25% stays intravascular
How does a septic shock differ from a hypovolaemic shock
Septic shock has warm peripheries and it is in the presence of an infection, potentially +vs BC with a raised lactate and WBC CRP.
How do aspirin and clopidogrel work
Both are anti-platelet agents and prevent platelet aggregation
Both roughly last 8 days as this is the lifespan of a platelet
Aspirin - irreversible COX 1 and 2 inhibition
Clopi: Reduces platelet aggregation through irreversible inhibition of receptor for ADP on cell membranes
What is respiratory failure
The inability of the body to maintain adequate arterial oxygenation. Typically PaO2 less than 8
What is the formula for ventilation
Tidal volume x resp rate
What is the minute ventilation for a 70kg man
Normal tidal volume is 7ml per kg
Hence
Ventilation = TV x RR = 500ml x 12 = 6L/min
When should patients be weaned off a ventilator
When the initial injury has subsided
Adequate gas exchange
Adequate respiratory drive and power
What is the classification used for pelvic fractures
Young and burgess
1) Anterior - posterior compression
2) Lateral compression
3) Vertical sheer - associated with falling from a height
At what level should a pelvic binder be applied
At the level of the greater trochanters
What are the options for pelvic haemorrhage
Activate MHP
Pelvic binding
IR and embo
Peritoneal packing
Urgent vascular opinion if very large vessel
What is the lethal triad in trauma
Hypothermia, acidosis and coagulopathy
What are the features of TURP syndromes
Confusion, hypotension, restlessness, blurred vision
The use of glycerine rich hypotonic solution causes it. This can cause severe dilutional hyponatraemia
How does hyponatraemia cause confusion
By causing cerebral oedema
How would you manage TURP syndrome
Keep operating time low of less than 1 hour
Change irrigation fluid to NACL
Management of hypotension
Ask anaesthetics to consider intubation
ICU or HDU
What is the metabolic response to injury
Ebb phase where there is reduced CO and metabolic rate with hypothermia
Flow phase which is made up of catabolic and anabolic phases
What is the resp quotient
It is the ratio of CO2 excretion to O2 consumption.
RQ of carbs is 1
Protein is 0.9 and Fat is 0.7
What is the difference between NJ and NG tubes
NJ are longer and narrower and are more prone to kinking
NJ bypasses the stomach and hence there is a reduced risk of aspiration
NJ is placed under endoscopic/fluoroscopic guidance leading to a delay in feeding
Why is NJ preferred in pancreatitis
As it bypasses the duodeno-jejunal flexure. Food passing through this region can cause a release of cholecystokinin which exacerbates the inflammatory process
How is tolerance to feeding monitored
Absorption and SE such as NVD and aspiration of feed
Blood test can also be helpful
How would you improve poor tolerance to feeding
NJ, check position, dietitian input, monitor bloods
What are some of the complication of burns
Fluid shift and hypothermia
Inhalation injury
Renal failure
ARDS
DIC
What is the definition of ARDS
Diffuse form of lung injury associated with reduced lung compliance, marked pulmonary infiltration and hypoxaemia
What is the difference between spinal shock and neurogenic shock
In spinal shock, there is total and complete loss of power, sensation and reflexes below the level of the injury
Neurogenic shock is a sudden loss in the sympathetic nervous system response
What are the contraindications for a urinary foley catheter placement
Pelvic fracture
Urethral and penile trauma
Primary vs secondary brain injury
Primary is at the time of injury and secondary is after such as hypoxia, hypotension, raised ISCP
What are the vitals for children
Systolic BP = 90 + (age x 2)
Diastolic BP 2/3 systolic BP
Lowest systolic BP = 70 + (agex2)
WHat is the initial resuscitation formula for children
20ml/kg of initial crystalloid
What diuretic to use in TURP syndrome
Mannitol
Cause of death in liver cirrhosis
Varicies
Why is vascular surgery more pro-coagulant
Because there is more endothelial injury and all fibrinolysis is temporarily shut down
What is the definition of massive blood loss
Entire blood volume in about 24 hours
>50% blood volume loss in 3 hours
>150ml/min
Why does warfarin need to be bridged
In the acute period, it can cause a more coagulable state by inactivation of protein C.
What is the difference between UFH and LMWH
LMWH is sorter chain and only works on Factor 10 and is more predictable
UFH is a longer chain and works on factor 2 and 10 and hence is more unpredictable
UFH requires aptt monitoring and LMWH requires no monitoring
What are the types of surgical haemorrhage
Primary: Bleeding occurs in the surgery
Refractionary: 24 hours bleeding due to slipping of staple for eg
Secondary: In 2 weeks time due to sloughing of vessel for example
