Basic Science And Equipment

Question 1

Cause of sigmoid curve

Answer 1

Cooperative binding of oxygen and haemoglobim

Question 2

Normal values p50 p75 (venous blood) and p100 (arterial blood)

Answer 2

P50 3.5kpa
P75 5.3kpa
P100 13

Question 3

Causes right shift oxy hb dissociation curve

Answer 3

Causes of right shift of p50

Reduces affinity of hb for oxygen (ie ocygen released)

Acidosis temperature 23 dpg

Question 4

Causes of left shift of oxygen hb curve

Answer 4

Alkalosis reduced 23 dpg hypothermia
Feral hb
Carboxyhb
Methaemoglobinaemia

Causes hb to hold onto oxygen

Question 5

Bohr effect

Answer 5

Co2 released at tissues equals rise in hydrogen ions
Hydrogen binds to hb
Hb releases more oxygen to tissues

Question 6

Double Bohr effect

Answer 6

Fetus release co2 at placenta
Increased hydrogen ion concentration changes hb (right shift) and oxygen released to placenta

On foetal side as co2 released more alkalotic resulting in left shift and more o2 taken up

Question 7

Laser properties

Answer 7

Coherent ( in plane)
Collimated (one direction)
Monochromatic (one wavelength)

Question 8

Types laser

Answer 8

Co2
Argon
Ndyag

Question 9

Reducing risk airway fire

Answer 9

Lowest fio2 less than 0.25 
No nitrous 
Laser tube
Saline in cuff 
Wet swabs 
Pre filled saline syringes 
Matt black instruments

Question 10

Hazards of laser

Answer 10

Airway fire
Burns
Atmospheric pollution
Eye damage

Question 11

Spatial resolution

Answer 11

Spatial resolution is the ability to differentiate 2 points at particular depth in tissue

Question 12

Axial resolution

Answer 12

Minimum distance between two reflectors in parrelel

Question 13

Lateral resolution

Answer 13

Minimum distance between 2 reflectors next to each other

Question 14

Temporal resolution

Answer 14

Ability to distinguish instantaneous events - TIME from first frame to the next

Question 15

Uses of u,trasound in anaesthesia

Answer 15

IV access 
Epidural 
Nerve blocks 
Echo 
Oesophageal Doppler

Question 16

Limitations of uktrasound

Answer 16

Operator dependent
Obesity deep structure
Age atrophied tissues

Question 17

What is secreted from adrenals

Answer 17

Medulla (inner) is chroma fun cells and secretes catecholamimes

Cortex outer
(GFR fr9m outside in)
Zona glomerulosa is aldosterone
Zone fasiculata and reticularis is corticosteroids and androgens

Question 18

How does aldosterone work

Answer 18

Released in response to renin angiotensin system and small degree by acth

Causes sodium (and water) reabsorption dct 
At expense of k and h loss

Question 19

Types of hyper aldosteronism

Answer 19

1. Primary ie conns adrenal hyperplasia
   Secretion of aldosterone
2. Secondary aldosterone ie high levels renin and aldosteone due to CCF or liver cirrhosis

Question 20

Investigation in conns

Answer 20

Blood pressure
Hypo kalemia can be profound
Aldosteone to renin ratio
MRI adrenals

Question 21

Cushing syndrome features

Answer 21

Moon face striae buffalo hump, osteoporosis muscle weakness thin skin LVH

Mild mineracorticoid effect leading to hypokalemia

Question 22

Tests in cushings

Answer 22

Dex suppression test
ACTH
MRI

Question 23

Hypoadrenalism

Answer 23

Primary ie Addisons (autoimmune, TB cancer haemorrhage)

Secondary due to prolonged steroids and withdrawal

Addisons abdo pain committing postural hypotension
Low sodium high potassium

Question 24

Tests for addisons

Answer 24

Short synacthen test- cortisol at baseline 30 mins and 60 short synacthen give 250 micros
Levels should double or more more than 580nmol l

Question 25

Decontamination

Answer 25

Decontamination removes or destroy a ally contaminagmgs so cannot reach susceptible site and cause harm

Cleaning plus either disinfection or sterilisation

Question 26

Bioburden

Answer 26

Population of viable infectious agents contaminating a medical device

Question 27

Critical semi critical and non critical devices

Answer 27

Critical tissues or vascular urge must be sterilised

Semi critical mucous membranes or non intact skin but shouldn’t break blood barrier ie laryngoscopes high level disinfection

Non critical ecg pulse ox can be cleaned

Question 28

Cleaning devices

Answer 28

Most important step remove foreign material and reduced bio burden

Washing with detergent or assisted washers ultra sonic

Question 29

Disinfection of devices

Answer 29

Removes most pathological organisms except spores (some high level disinfection may remove spores)

High level disinfectants aldehyde chlorine

Low level alcohol

Chemical disinfection rapid and cheap but may be corrosive or flammable
Rinsed and dried after

Pasteurisation intermediate level disinfection with mater over 77 degrees for 30 mins

Endoscopes need high level disinfection aldehyde minimum 20 mins

Question 30

Sterilisation

Answer 30

Should removed all pathological organisms including spores

Steam sterilisation over 100degrees dry and saturated recomomdede for devices that can withstand heat and moisture

Chemical sterilisation
Ethylene oxide in us
Aldrehyde 10 hours in U.K.