Orthopaedic Surgery Flashcards
Steph Risk factors for delirium after hip fracture surgery include all EXCEPT
a) Frailty
b) Age
c) GA vs Neuraxial technique
d) Male Sex
c) GA vs Neuraxial
Neuraxial versus general anesthesia in elderly patients undergoing hip fracture surgery and the incidence of postoperative delirium: a systematic review and stratified meta-analysis:
This meta-analysis did not find any statistically significant difference in POD incidence between NA and GA groups or in any subgroup analyses. There was no difference in delirium incidence regardless of inclusion or exclusion of patients with pre-existing dementia or preoperative delirium
a) Frailty, b) Age -> risk factors
Most notably, neck of femur fracture repair is associated with up to 70% risk of postoperative delirium. There are several explanations: a neck of femur fracture is commonly associated with frail older patients; perioperative pain is a significant issue; and the surgery is usually done in an emergency setting with limited opportunity for preoperative optimisation
BJA
d) Male sex -> risk factor
Male sex associated with increased risk of delirium, multiple studies on Google
An 85-year-old is scheduled for open reduction and internal fixation of a fractured neck of femur today. They have no significant past medical history. Preoperative review including physical examination, full blood count, electrolyte profile and electrocardiogram performed yesterday were normal. In the anaesthetic bay, the monitor shows the patient to be in atrial fibrillation with a ventricular rate of 110 to 145 beats per minute. The blood pressure is 130/80 mmHg. The best initial treatment for the atrial fibrillation is:
A) Amiodarone
B) Metoprolol
C) Digoxin
D) Induce then cardiovert
E) Calcium Channel Blocker
B) Metoprolol
Guidelines from the American College of Cardiology/American Heart Association (ACC/AHA) and the European Society of Cardiology (ESC) recommend beta-blockers as a first-line therapy for rate control in atrial fibrillation.
Reference: January CT, Wann LS, Calkins H, et al. 2019 AHA/ACC/HRS focused update of the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation. 2019;140(2)
The strongest independent preoperative predictor of chronic postsurgical pain after knee arthroplasty is:
a) Anxiety
b) Depression
c) Catastrophising
d) Female
KATE
Catastrophizing
A 30-year-old athlete undergoing a knee arthroscopy under general anaesthesia
develops intraoperative tachycardia. A 12-lead electrocardiogram is obtained and
shown below. The most likely diagnosis is:
a) AF
b) Flutter
c) AVNRT
d) Multifocal atrial tachycardia
AT
Repeat
Delta waves present, therefore WPW = AVRT
WPW + delta wave = AVRT → anatomical re-entry circuit (Bundle of Kent)
AVNRT is a functional re-entry circuit within the AV node
ECG features of AVNRT
● Regular tachycardia ~140-280 bpm
● Narrow QRS complexes (< 120ms) unless there is co-existing bundle branch block, accessory pathway, or rate-related aberrant conduction
● P waves if visible exhibit retrograde conduction with P-wave inversion in leads II, III, aVF. They may be buried within, visible after, or very rarely visible before the QRS complex
https://litfl.com/supraventricular-tachycardia-svt-ecg-library/
A 70-year-old patient booked for a revision total hip replacement is reviewed in preadmission clinic ten days before surgery. The following blood test results are
noted:
haemoglobin 110 g/L
ferritin 51 mcg/L
CRP (c-reactive protein) 10 mg/L
The most appropriate management for this patient should be to:
a) Proceed
b) Give PO iron and delay 6 weeks
c) Give IV iron
d) Blood transfusion pre-op
Victoria
Screenshot sent to JJ
B
A 55-year-old with no past history of ischaemic heart disease is three days post-total hip replacement surgery. They have an episode of chest pain at rest with features typical of angina that lasts 30 minutes before fully resolving. There are no electrocardiogram changes and no troponin rise. The diagnosis is
a. No diagnosis made
b. Unstable angina
c. STEMI
d. NSTEMI
e. MINS
REPEAT
b. Unstable angina
UTD:
Unstable angina (UA) and acute non-ST elevation myocardial infarction (NSTEMI) differ primarily in whether the ischemia is severe enough to cause sufficient myocardial damage to release detectable quantities of a marker of myocardial injury (troponins):
●UA is considered to be present in patients with ischemic symptoms suggestive of an ACS and no elevation in troponins, with or without electrocardiogram changes indicative of ischemia (eg, ST segment depression or transient elevation or new T wave inversion).
●NSTEMI is considered to be present in patients having the same manifestations as those in UA, but in whom an elevation in troponins is present.
MINS: Myocardial injury after non-cardiac surgery (up to 30 days post-op):
1. Elevated postop troponin
2. Resulting from myocardial ischaemia (i.e. no evidence of a non-ischaemic aetiology), not requiring an ischaemic feature (i.e. no chest pain, no ECG change)
VISION studies (Vascular Events in Noncardiac Surgery Patients Cohort Evaluation) demonstrated that severity of MINS strongly associated with 30-day mortality after NCS.
hs-cTnT
<20ng/L ~ 0.5% 30 day mortality
20-64ng/L ~3% 30 day mortality
65-999 ng/L ~9% 30 day mortality
>1000ng/L ~30% 30 day mortality
Whilst VISION trial identified MINS in at risk patients, the question now becomes what interventions are available to prevent this complication?
20.2 A Jehovah’s Witness patient attends for a revision total hip replacement and is medically optimized. You consider she is high risk for the procedure but after extensive discussion agree to proceed, including agreeing that you will not give blood under any circumstances. Your decision can be justified on the basis of
a) Paternalism
b) Non maleficence
c) Autonomy
d) Beneficence
a) Autonomy
- Obligation to respect the decision-making capacities of persons.
Non-maleficence: Obligation to avoid causing harm
- If refused to proceed.
Paternalism: A set of attitudes and practices in which the health provider determines that a patient’s wishes or choices should not be honored.
- If transfused patient against their wishes
Beneficence: Obligation to provide benefits and to balance benefits against risks; obligation of physician to act for the benefit of the patient
- Controversial interpretation in this case. Both proceeding and refusing to do case may be acting for the benefit of the patient, depending on how you look at the scenario.
BJA: ‘MORAL balance’ decision-making in critical care
https://www.bjaed.org/article/S2058-5349(18)30145-8/fulltext
22.2 Despite an interscalene block being performed preoperatively for arthroscopic rotator cuff repair, a patient wakes up with posterior shoulder pain. The most appropriate procedure to consider would be a nerve block of the
a. Supraclavicular nerve
b. Suprascapular nerve
c. Medial pectoral
d. Vagus nerve
b. Suprascapular nerve
Suprascapula nerve (C5,6)
- innervates supra and infraspinatus
- comes off superior trunk of the brachial plexus, and is usually anaesthetised by an interscalene block
- sensory innervation to 70% posterior-superior shoulders and portion of the anterior axilla and the ACJ
Supraclavicular nerve (C3,4)
- provides sensory to the ‘cape’ of the shoulder
- component of the cervical plexus block
- lies outside the brachial plexus
- commonly missed during supraclavicular brachial plexus blocks
Subscapular nerve:
- subscapularis
- medial rotation shoulder
Dorsal scapular nerve:
- branch of the brachial plexus
- supplies rhomboid major muscle, rhomboid minor muscle, and levator scapulae muscle
- causes the scapula to be moved medially towards the vertebral column
- Dorsal scapular nerve syndrome can cause a winged scapula, with pain and limited motion
Thoracodorsal nerve:
- thoracodorsal nerve also branches from the posterior division of the brachial plexus
- this nerve innervates the latissimus dorsi muscle.
https://resources.wfsahq.org/atotw/the-shoulder-block/
22.2 For a 70-year-old patient on rivaroxaban with normal renal function a major guideline recommends proceeding with hip fracture surgery after two half-lives of the drug. This equates to
a. 12 hours
b. 24 hours
c. 48 hours
d. 72 hours
e.
b. 24 hours
ASA guidelines
-If creatinine clearance >/=30 ml.min-1 (Cockcroft-Gault), proceed with surgery after two half lives (24 h) since the last dose, under general anaesthesia (or spinal anaesthesia if indicated)
- If creatinine clearance < 30 ml.min-1, proceed with surgery after four half lives (48 h) since the last dose, under general anaesthesia (or spinal anaesthesia if indicated)
21.2 A 30 year old athlete undergoing a knee arthroscopy under general anaesthesia becomes tachycardic intraoperatively. A 12-lead electrocardiogram (ECG) is obtained. The most likely diagnosis is
a) Atrial fibrillation
b) Atrial flutter
c) Sinus tachycardia
d) WPW
d) WPW
Type B pattern
LITFL:
ECG features of WPW in sinus rhythm
-> PR interval < 120ms
-> Delta wave: slurring slow rise of initial portion of the QRS
-> QRS prolongation > 110ms
-> Discordant ST-segment and T-wave changes (i.e. in the opposite direction to the major component of the QRS complex)
-> Pseudo-infarction pattern in up to 70% of patients — due to negatively deflected delta waves in inferior/anterior leads (“pseudo-Q waves”), or prominent R waves in V1-3 (mimicking posterior infarction
Can be left-sided (Type A) or right-sided (Type B), and ECG features will vary depending on this:
Left-sided AP:
produces a positive delta wave in all precordial leads, with R/S > 1 in V1.
(Dominant R Wave in V1)
Sometimes referred to as a type A WPW pattern
Right-sided AP:
produces a negative delta wave in leads V1 and V2.
Sometimes referred to as a type B WPW pattern
Tachyarrhythmias in WPW
There are only two main forms of tachyarrhythmias that occur in patients with WPW
- Atrial fibrillation or flutter.
-> Due to direct conduction from atria to ventricles via an AP, bypassing the AV node - Atrioventricular re-entry tachycardia (AVRT).
-> Due to formation of a re-entry circuit involving the AP
Breakdown of Type A example:
- Sinus rhythm with a very short PR interval (< 120 ms)
- Broad QRS complexes with a slurred upstroke to the QRS complex — the delta wave
- Dominant R wave in V1 suggests a left-sided AP, and is sometimes referred to as “Type A” WPW
- Tall R waves and inverted T waves in V1-3 mimicking right ventricular hypertrophy (RVH) — these changes are due to WPW and do not indicate underlying RVH
- Negative delta wave in aVL simulating the Q waves of lateral infarction — this is referred to as the “pseudo-infarction” pattern
20.2 A 55 year old man with no past history of ischaemic heart disease is 3 days post total hip replacement surgery. He has an episode of chest pain that sounds ischaemic, began at rest and lasts thirty minutes before resolving fully. There are no ECG changes nor troponin rise. The diagnosis is
a. No diagnosis made
b. Unstable angina
c. STEMI
d. NSTEMI
e. MINS
b. Unstable angina
Not a Repeat, no Tropnin rise in this question making the answer unstable angina as opposed to NSTEMI
UTD:
Unstable angina (UA) and acute non-ST elevation myocardial infarction (NSTEMI) differ primarily in whether the ischemia is severe enough to cause sufficient myocardial damage to release detectable quantities of a marker of myocardial injury (troponins):
●UA is considered to be present in patients with ischemic symptoms suggestive of an ACS and no elevation in troponins, with or without electrocardiogram changes indicative of ischemia (eg, ST segment depression or transient elevation or new T wave inversion).
●NSTEMI is considered to be present in patients having the same manifestations as those in UA, but in whom an elevation in troponins is present.
MINS: Myocardial injury after non-cardiac surgery (up to 30 days post-op):
1. Elevated postop troponin
2. Resulting from myocardial ischaemia (i.e. no evidence of a non-ischaemic aetiology), not requiring an ischaemic feature (i.e. no chest pain, no ECG change)
VISION studies (Vascular Events in Noncardiac Surgery Patients Cohort Evaluation) demonstrated that severity of MINS strongly associated with 30-day mortality after NCS.
hs-cTnT
<20ng/L ~ 0.5% 30 day mortality
20-64ng/L ~3% 30 day mortality
65-999 ng/L ~9% 30 day mortality
>1000ng/L ~30% 30 day mortality
Whilst VISION trial identified MINS in at risk patients, the question now becomes what interventions are available to prevent this complication?
21.1 The independent predictors for severe bone cement implantation syndrome (BCIS) in cemented
hemiarthroplasty for hip fracture do NOT include
a. Male
b. GA
c. severe cardiopulmonary disease
d. Diuretic use
e. Age
b. GA
Independent predictors for severe BCIS were:
ASA grade III—IV
chronic obstructive pulmonary disease
medication with diuretics or warfarin
Source: BJA 2014 Article
https://academic.oup.com/bja/article/113/5/800/2920080
21.2 A factor that is NOT used to calculate the Child-Pugh score is
a) Albumin
b) Bilirubin
c) INR
d) Creatinine
e) Ascites
d) Creatinine
- Originally devised to predict outcomes in Cirrhotic patients undergoing portosystemic Surgery
- Assess perioperative risk for patients with liver disease who undergo hepatic or non-hepatic surgery
- Factors include:
o Encepahlopathy
§ None +1
§ Mild to moerate + 2
§ Severe +3
o Ascites
§ None +1
§ Mild to moderate (diuretic responsive) +2
§ Severe (diuretic refractory) +3
o Bilirubin
§ <2 mg/dl +1
§ 2-3mg/dl +2
§ >3 mg/dl +3
o Albumin
§ >3.5g/dl +1
§ 2.8-3.5g/dl +2
§ <2.8g/dl +3
o INR
§ <1.7 +1
§ 1.7-2.3 +2
§ >2.3 +3 - Class A 5-6 points
o 1-5yr survival rate 95% - Class B 7-9 points
o 1-5 year survival rate 75% - Class C 10-15 points
1-5 yr survival rate 50%
Original study Mortality rates in patients who undergo abdominal surgeries:
- Class A 10%
- Class B 82%
- Class C 82%
Newer Study mortality rates after surgery:
- Class A 2%
- Class B 12%
- Class C 12%
Drawbacks:
- Subjective measurement of:
o ascites
o encephalopathy
- Does not consider
o Pre-op infection
o Aetiology of cirrhosis
o Surgery type
22.1 A patient in atrial fibrillation with a CHA2DS2-VASc score of 2 has presented for elective hip surgery. Warfarin had been ceased for four days preoperatively and on the day before surgery the international normalized ratio (INR) was 2.1. The best course of action at this point is to
a) Postpone surgery
b) Vitamin K 3mg IV
c) Prothrombinex 25IU/kg
d) Cell saver intraop
e) Proceed with surgery
Give 3mg of Vitamin K and re-check on day of surgery proceed if INR <1.5 on DOS
22.1 A 65-year-old man presents to the preadmission clinic two weeks prior to his total knee replacement. His blood results include haemoglobin 100 g/L, ferritin 20 μg/L and normal C-reactive protein. The best course of action is to
a. Proceed
b. EPO and iron
c. Iron tablet and delay 3 months
d. Iron transfusion and proceed
e. PRBC
Postpone 3 months and give oral iron
20.1 70 year old patient for revision THR, in clinic 10 days prior
Hb 110
Ferritin 51
CRP 10
What should you do?
a Transfuse 2u pRBC
b Give oral iron therapy and continue with surgery
c Give oral iron therapy and defer surgery for 6 weeks
d Give IV iron
e Do nothing
c Oral iron and defer
or
d give IV iron
- most assume its IV iron and proceed but
- Assuming IDA and raised CRP then iron therapy but
‘deferable’ surgery? then oral and come again in 6 weeks
if not deferrable then IV iron - surely a revision THR is deferable?? - If give IV iron and defer was an option I would choose that one, it would allow assessment of inflammatory process and to confirm Hb and ferritin are at an acceptable level
International consensus statement on the peri-operative management of anaemia and iron deficiency
https://associationofanaesthetists-publications.onlinelibrary.wiley.com/doi/10.1111/anae.13773
However, many patients will not respond to oral iron, especially those with functional iron deficiency and chronic illness or infection and those with ongoing blood loss 15, 25. Others will not tolerate oral iron due to gastro-intestinal side-effects. Once oral iron has been commenced, the Hb should be measured again, at least 4 weeks before surgery. In the absence of an increased Hb or if the patient is intolerant, i.v. iron is the preferred replacement route. If surgery is planned in less than 6 weeks time, i.v. iron may also be the most effective option.
