Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

eMRCS questions > Stats in surgery > Flashcards

Stats in surgery Flashcards

1
Q

Assuming that the results are normally distributed, what percentage of values lie within two standard deviations of the mean ?

A

95%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Properties of normal districbution

A

symmetrical i.e. Mean = mode = median
68.3% of values lie within 1 SD of the mean
95.4% of values lie within 2 SD of the mean
99.7% of values lie within 3 SD of the mean

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Types of audit

A

Financial - historical- fairness, accuracy, and reliability of financial data

Operational - future- primary sources of evidence are the operational policies and achievements

Departmental review - A current period analysis of administrative functions, to evaluate the adequacy of controls, safeguarding of assets, efficient use of resources, compliance with related laws, regulations and institutional policy and integrity of financial information.

Standards- Comparison of care or passage of care against set and widely agreed standards or outcomes.

Systems - Evaluation of processes occurring within an institution- If the problem is related to a breakdown in the system or technology infrastructure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which device would be most suited for resection of a parietal lobe tumour?

A

CUSA device

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How Is data from multiple RCT best displayed

A

Forest plot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Who to report to if patient in a study experiences an adverse outcom

A

Ethics committee

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Calculating RR

A

Exp event rate
Control event rate

RR=EER/CER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

When to use bipolar over monopolar

A

Bipolar is most commonly used in operations of the digits/penis (to avoid monopolar current focused over a smaller region), in patients with pacemakers (to avoid electrical involvement with the pacemaker), or in microsurgery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does a p value represent

A

Risk of type 1 error

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Type 1 vs 2 error

A

Type 1 Error
the null hypothesis is rejected when it is true - i.e. Showing a difference between two groups when it doesn’t exist, a false positive
Rate of type 1 error is the given the value of α
It usually equals the significance level of a test

Type 2 Error
the null hypothesis is accepted when it is false - i.e. Failing to spot a difference when one really exists, a false negative.
Rate of type 2 errors is given the value of β
It is related to the power of the test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Diathermy used in thyroid gland surgery

A

Bipolar to minimise risk to RLN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does a null hypothesis state

A

A null hypothesis (H0) states that two treatments are equally effective (and is hence negatively phrased). A significance test uses the sample data to assess how likely the null hypothesis is to be correct.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Alternative hypothesis states

A

The alternative hypothesis (H1) is the opposite of the null hypothesis, i.e. There is a difference between the two treatments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Incidence vs prevalence

A

The incidence is the number of new cases per population in a given time period.

The prevalence is the total number of cases per population at a particular point in time.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Number needed to treat calculation

A

1/ARR

ARR= RT- RT2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Case control vs cohort

A

Cohort - measure RR
Observational and prospective

Case control- Observational and retrospective
OR
Useful for studying rare conditions
Prone to confounding

17
Q

If a dataset requires multiple testing

A

Use Bonferroni correction

18
Q

Tests for not normal distributions

A

Chi Squared and Mann Whitney U tests

Sample size small- Fischer

19
Q

What has the biggest impact on PPV

A

Prevelance

20
Q

Definition of PPV< NPV, Sens, spec

A

The positive predictive value (PPV) is the probability that an individual with a positive screening result has the disease. The sensitivity is the probability that an individual with the disease is screened positive and the specificity is the probability that an individual without the disease is screened negative.
Its value depends upon the prevalence of the condition being tested for and the sensitivity of the test used.
It may be calculated by dividing the number of true positives by the number of true positives and the number of false positives. §]

21
Q

Levels of evidence

A

I - evidence from meta-analysis of randomised controlled trials
II - evidence from at least one well designed controlled trial
III - evidence from correlation and comparative studies or use of historical controls
IV - evidence from case series
V - Expert opinion or founded on basic principles

22
Q

Components for power calculation

A

Size of effect
Significance level
Sample size used to detect the effect
Desired power value

23
Q

Mean in relation to median with skew

A

In a left-skewed distribution, the mean is less than the median

24
Q

Child is unstable requires blood, parents refuse what do you do

A

Treat in emergencies

25
Q

Pre- and post- test odds and probability

A

Pre test prob= prevelencne

Pre test odds= PreTP/1-PreTP
Post test odds= PreTO x likelihood
Post test probs= PostTO/1-PostTO

26
Q

Montgomery ruling

A

The doctor is therefore under a duty to take reasonable care to ensure that the patient is aware of any material risks involved in any recommended treatment, and of any reasonable alternative or variant treatments.

27
Q

Cluster trials

A

Groups are randomised rather than individuals

Require increased recruitment to achieve same stat power as individual

more prone to unit of analyses errors than individual based trial

Analysis is more complex

28
Q

Intention to treat analysis

A

An intention to treat analysis considers data according to the treatment to which the patient was randomised, rather than the treatment which was recieved.

29
Q

Bolam test

A

decision made by a doctor is in agreement with the professional standard of medical practise.

30
Q

Consent forms

A

1- competent adults, consciousness may be impaired
2- adult on behalf of child
3- not impaired
4- adult lacking capacity

31
Q

When is a MCA advocate needed

A

Patient requires intervention
Time pressure
Lacks capacity for themselves

a best interests decision is required because the doctor has assessed the person as not having the capacity to make the decision themselves
the person does not have family or friends with whom it is appropriate to consult about the decision.

32
Q

What does r represent

A

Correlation coefficient

33
Q

Levels of evidence

A

1a- systematic review of RCTs
2- cohort
3- case- control
4- case series
5- expert opinion

a- systematic review of
b- individual

34
Q

p value of 0.05

A

<5% due to chance

35
Q

Friedman test use

A

3 or more
Non parametrical- not normal distribution

36
Q

95% CI meaning

A

That 95% confidence that the true population value lie within this range

37
Q

Chi squared test vs t test

A

T test for continuous data

Chi squared for categorical - they either did or they didnt

38
Q
A

eMRCS questions (45 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions