ASCC

Question 1

ARDS CXR

Answer 1

Bilateral pulmonary infiltrates

Question 2

ARDS definition

Answer 2

Acute, diffuse, inflammatory form of lung injury (acute respiratory failure) Characterized by:
1. Hypoxemia
2. Decreased lung compliance
3. Diffuse pulmonary infiltrates on CXR
4. Normal PAWP (< 18 mmHg)
5. PaO2/ FiO2 < 26.6

Question 3

Normal value of ICP?

Answer 3

7-15 mmHg

Question 4

What is the Cushing reflex?

Answer 4

Physiologic nervous system response (mixed vagal and sympathetic stimulation) to an elevated ICP that results in Cushing’s triad. It leads to hypertension, which ensures an adequate CPP, bradycardia and irregular breathing

Question 5

Pathophysiology of increased ICP?

Answer 5

Monro/Kellie doctrine

Question 6

Management of raised ICP

Answer 6

Elevate bed to 30 degrees
Mannitol
Reduce PaCO2
Surgical decompression/EVD

Question 7

Agents given in neurogenic shock?

Answer 7

Vasopressors (i.e. dopamine, norepinephrine)

Question 8

Difference between spinal and neurogenic shock?

Answer 8

Neurogenic is loss of sympathetic nervous system signals whereas spinal is loss of total power, sensation and reflexes below level of injury

Question 9

Normal compartment pressure

Answer 9

0-15mmHg
>30 - fasciotomy

Question 10

Why do you get acute renal failure with compartent syndrome?

Answer 10

ATN due to nephrotoxic effect of myoglobin precipitation in renal tubules

Question 11

Pathogenesis of portal HTN in chronic alcoholism:

Answer 11

Cirrhosis resulting from chronic liver disease and is characterized by liver cell damage, fibrosis and nodular regeneration. The fibrosis obstructs portal venous return and portal hypertension develops.
* Arteriovenous shunts within the liver also contribute to the hypertension.

Question 13

How can NSAID’s causes peptic ulceration?

Answer 13

Topical irritant effect of these drugs on the epithelium,
* Impairment of the barrier properties of the mucosa
* Suppression of gastric prostaglandin synthesis, (inhibition of cyclooxygenase, COX1)
* Reduction of gastric mucosal blood flow
* Interference with the repair of superficial injury.

Question 14

Mechanism of action of PPI?

Answer 14

The PPI binds irreversibly to a hydrogen/potassium ATPase enzyme (proton pump) on gastric parietal cells and blocks the secretion of hydrogen ions, which combine with chloride ions in the stomach lumen to form HCL

Question 15

Actions of HCL?

Answer 15

Activates pepsinogen to pepsin which help in proteolysis
* Antimicrobial
* Stimulates small intestinal mucosa to release CCK and secretin
* Promotes absorption of calcium and iron in the small intestine

Question 16

NCEPOD meaning and classification

Answer 16

National Confidential Enquiry into patient outcomes and death classification
1- immediate
2 - urgent
3 - expedited
4 - elective

Question 17

In what form does bilirubin circulate within the plasma?

Answer 17

Free bilirubin, conjugated to glucaronic acid or bound to albumin

Question 18

Bilirubin metabolism

Answer 18

Conjugated bilirubin goes into the bile and thus out into the small intestine. Though most bile acid is resorbed in the terminal ileum to participate in enterohepatic circulation, conjugated bilirubin is not absorbed and instead passes into the colon
* There, colonic bacteria disconjugate and metabolize the bilirubin into colorless urobilinogen, which can be oxidized to form stercobilin, these give stool its characteristic brown color
50% of the urobilinogen is reabsorbed into the
enterohepatic circulation to be re-excreted in
the bile: some of this is instead processed by
the kidneys, coloring the urine yellow.

Question 19

Classify post-obstructive jaundice

Answer 19

Intramural (CBD stones)
Transmural (strictures)
Extramural (pancreatic cancer)

Question 20

Causes of jaundice

Answer 20

Pre-hepatic (haemolytic anaemia, G6PD)
Hepatic - ALD, hepatitis, HCC
Post-hepatic - Gallstones, cholangiocarcinoma

Question 21

Why not morphine in pancreatitis?

Answer 21

Spinchter of oddi constriction

Question 22

Difference between true pancreatic cyst and pseudocyst?

Answer 22

A pseudocyst isn’t closed and doesn’t have a lining of epithelial cells separating it from the nearby tissue.

Question 23

Summary of calcium homeostasis

Answer 23

The actions of the three principal hormones that regulate the plasma concentration of Ca+2
PTH increases plasma Ca+2 by mobilizing this ion from bone. It increases Ca+2 reabsorption in the kidney, but this may be offset
by the increase in filtered Ca2+. It also increases the formation of 1,25-dihydroxycholecalciferol. 1,25-Dihydroxycholecalciferol
increases Ca+2 absorption from the intestine and increases Ca+2 reabsorption in the kidneys. Calcitonin inhibits bone resorption
and increases the amount of Ca+2 in the urine.

Question 24

Difference between T3 and T4?

Answer 24

T3 is more biologically active, less
protein binding capacity
* T4 is in vitro inactive, more protein
binding capacity

Question 25

What is the pain pathway

Answer 25

Pain is transmitted via fast A-delta fibers (sharp pain) and slower C fibers (dull pain) to lateral spinothalamic tract then to the thalamus

Question 26

Where is ADH (vasopressin) produced and what factors stimulate its secretion?

Answer 26

Produced in the hypothalamus then transported, stored and released from the posterior pituitary Factors stimulating its secretion * Reduce circulating volume * Increased plasma osmolarity AT2

Question 27

Action of ADH

Answer 27

In collecting duct Vasopressin - constrict arterioles - Increase peripheral vascular resistance

Question 28

Angiotensin 2 effects

Answer 28

Arteriolar constriction and a rise in systolic and diastolic blood pressure. Acts directly on the adrenal cortex to increase the secretion of aldosterone. Direct effect on the renal tubules to increase Na+ reabsorption

Question 29

RAAS description

Answer 29

Kidneys detect decrease in BP and release renin from JGA Renin converts angiotensinogen to AT1 ACE in lungs convert AT1 to AT2 AT2 causes vasonconstriction + aldosterone (salt and water retention) - increase in BP

Question 30

Advantages and disadvantages of naso-jejunal tube?

Answer 30

Advantages * Bypass the Stomach o less liability to pneumonia o Avoids gastric phase of stimulation o Doesn’t stimulate pancreatic secretions o Feed delivered directly to the intestine thus maintaining mucosal integrity Disadvantages * Needs endoscopic guidance for placement * Smaller in diameter (more prone to kinking)

Question 31

One risk of TPN

Answer 31

Mucosal atrophy leading to bacteria translocation due to hormones not being produced as not stimulated (ones that maintain mucosal integrity)

Question 32

What are the disadvantages of using glucose as the main energy source?

Answer 32

Glucose intolerance: as part of the stress response, critically unwell patients are often in a state of hyperglycemia and glucose intolerance. Therefore, if glucose is the only source of energy, patients will not receive their required daily amount due to poor utilization of their energy source * Fatty liver: the excess glucose occurring as a consequence of the above is converted to lipid in the liver, leading to fatty change. This may derange the liver function tests * Respiratory failure: the extra CO2 released upon oxidation of the glucose may lead to respiratory failure and increased ventilatory requirements * Relying solely on glucose may lead to a deficiency of the essential fatty acids. Therefore, ∼ 50% of the total energy requirement must be provided by fat.

Question 33

How to calculate HR based on this ECG?

Answer 33

300/number of large squares in R-R interval If irregular, no. of QRS in 30 large squares x10

Question 34

Perioperative hypothermia

Answer 34

<36

Question 35

Complications of hypothermia

Answer 35

Coagulopathy, cardiac arrythmia, myocardial ischaemia, decrease ventilator drive, decreased renal blood flow, left shift of oxygen dissociation curve, reduced gut motility, impaired neurological state

Question 36

How to measure intraop core temp

Answer 36

Oesophegeal probe

Question 37

DIC definition

Answer 37

It is a pathological consumptive coagulopathy due to activation of the coagulation and fibrinolytic systems, activation of the latter leads to formation of micro thrombi in many organs with the consumption of the clotting factors and platelets.

Question 38

Treatment of DIC

Answer 38

FFP, platelets, cryoprecipitate

Question 39

Haemostasis stages

Answer 39

1. Contraction of blood vessel 2. Platelet plug formation 3. Fibrin by coagulation cascade formation

Question 40

Which factors will be deficient in stored blood?

Answer 40

Factor V and VIII

Question 41

What is massive blood transfusion?

Answer 41

Replacement of 50% of patient's blood volume in 4 hrs

Question 42

What is the minimal UOP?

Answer 42

In adults, the minimum acceptable urine output is 0.5 ml/kg/h

Question 43

Can you explain why the patient is oliguric?

Answer 43

The most common cause is due to the physiological stress response to surgery in the first 24–36 hours post-operatively. This is due to circulating glucocorticoids and mineralocorticoids inducing salt and water retention. * Surgical trauma and anaesthetic - vasopressin release

Question 44

Why are uremic patients anaemic?

Answer 44

Deficiency of erythropoietin (most important cause) * Presence of circulating bone marrow toxins * Bone marrow fibrosis during osteitis fibrosa cystica

Question 45

Action of K+ on the cardiac muscle?

Answer 45

Excess K+ causes the heart to be dilated, flaccid and decreases the heart rate and can block the conduction of cardiac impulse

Question 46

K+ MOA cardiac muscle

Answer 46

Extracellular High K depolarizes the resting membrane potential causing it to be less negative which will decrease the intensity of action potential making the contraction weaker

Question 47

Loop diuretic MOA

Answer 47

Site of action: thick ascending limb of loop of Henle Mechanism: inhibit Na/K/2CL pump thus preventing NaCl absorption, so the distal convoluted tubules tries to preserve Na+ and lose K+ Rest act at DCT

Question 48

SIRS criteria

Answer 48

Criteria: (2 or more) * Temp. > 38 c or < 36 * RR > 20 * PaCO2 < 4.3 * Pulse > 90/min. * WBC's > 11 or < 4

Question 49

Inotrope MOA

Answer 49

drug increases cardiac contractility

Question 50

Vasopressor MOA

Answer 50

drug increases vasoconstriction, MAP

Question 51

Noradrenaline receptor

Answer 51

A1

Question 52

DOpamine receptor

Answer 52

D1, D2

Question 53

PE on CTPA

Answer 53

Filling defect in pulmonary vessels

Question 54

Where is the respiratory center

Answer 54

Pons and medulla oblongata (chemoreceptors)

Question 55

What is critical limb ischemia?

Answer 55

Critical limb ischemia is defined as ischaemic pain at rest, along with arterial ulceration and gangrene secondary to obstruction of the arterial vasculature.

Question 56

Can you define acute kidney injury

Answer 56

Increase in serum creatinine to ≥1.5 times baseline, which is known or presumed to have occurred within the prior seven days, or Urine volume <0.5 mL/kg/hour for six hours

Question 57

qSOFA score

Answer 57

qSOFA – score one for each: Breathing rate >22 Systolic blood pressure <100mmHg Mental alteration Organ dysfunction (score of 2 or more)