Cardiac Flashcards
RCRI
History of ischaemic heart disease 1
History of congestive heart failure 1
History of cerebrovascular disease 1
Use of insulin therapy for
diabetes 1
Preoperative serum creatinine >177 micromoles/L 1
High-risk surgery 1
Oxford
Risk for major CARDIAC complications
0 0.4%
1 1%
2 7%
3 11%
Who needs periop 12-lead ECG?
- pt > 65 yo
- intermediate risk surgery
- risk factors of IHD
Oxford
What are the 5 types of MI? %?
- acute atherothrombotic coronary event (25%)
- heterogeneous - imbalance of O2 supply and demand (75%)
- SCD unexpected
- ~ PCI
- ~ cardiac death
Oxford
Pharm therapy to reduce MACE risk
- Continue long term beta blocker (dec myocardial O2 demand)
- No - initial of bb 24h prior surgery
- Continue PRN nitrate
- Continue CCB - restart ASAP post op
- ACE/ARB - do not protect against MACE (But improve MI and LV dysfx survival)
- Statin - improve ST and LT outcome post non-cardiac and CABG (ESA/CCS)
Oxford
AMI
- myocardial cell death
- due to prolonged ischaemia
clinical evidence + cTNT
1+ ischaemic feature
(1. sx 2. new ECG changes 3. new RWMA 4. new cor thrombus)
cTNT
- rise 3-4h post injury
- up for 10-14d
- need 1 level >99th percentile required for dx
MINS
- definition
- incidence
- dx
- surveillance
- med mx
- Px relevant
- Myocardial injury
- Due to ischaemia
- 30d after non-cardiac sx
- pt w or w/o MI
- 20% of patients having non-cardiac surgery
- > 90% MINS - no signs/sx of ischaemia
- 20% meet MI definition
dx
1. cTNT >65ng/L
2. <30d non-cardiac Sx
3. Not due to non-ischaemic cause (e.g. AF, sepsis)
4. Not nec - sx/ECG changes
daily TnT levels on D1,2,3
- LD aspirin + statin
- ACE-i if HTN
- Anticoag (maybe) (MANAGE trial)
- ?cor angio and revasc
HF criteria
by 1. sx 2. LVEF 3. BNP/NT-proBNP 4. left heart enlargement/diastolic dysfx
<40% HFrEF
40-49% HFmrEF
50%+ HFpEF
HF mx
- delay sx progression
- optimise sx mx/FRC
- reduce mortality
HF treatment
2023b Outline the treatment strategies for chronic heart failure. pr75%
*best evidence for HFrEF
- Sacubitril/ABR OR ACEi / ARB
- b-blocker (caution with new/decom HF)
- MRA -
- Digoxin
a) AF in sx HF
b) SR in sev HF - Anticoag - HF/VTE
- No CCB
HFpEF *no reduction in morb/mort
- Diuretics
- Spiro
- bb and ACEi
Oxf Anaes
ACC/AHA
Stages
A - treat HTN
B - ACEi/ARB +/- BB
C/D - ACEi/ARB + BB + Diuretics +/- Dig +/- hydralazine/nitrate
CRT (25% pt with mod-sev HF HAS LBBB)
pacing LV and RV
- DCM EF <35%
- QRS > 120ms
- poor fx status despite max med rx
Oxf AT P.39
2023b Evaluate the use of each of the following for preoperative cardiac risk stratification:
1) plasma biomarkers (chose ONE of natriuretic peptides OR troponin)
2) Duke Activity Status Index (DASI) stair-climbing test,
3) cardiopulmonary exercise testing (CPX/CPET).
pr65%
- Plasma biomarker
BNP
Pros - High NPV for periop cardiac events
- Predictor of death/non-fatal MI at 30/180 days
Cons
1. Optimal threshold not established
2. Cost
e14 aha/acc 2024
- DASI
MET 1 = VO2 3.5mL/kg/min
METS 4 = 14mL/kg/min
Pros:
a) simple
b)
Cons:
a) bias
- CPEX
vital, non-invasive assessment technique used to evaluate the cardiopulmonary system during rest and exercise
measure functional capacity, which is crucial for predicting postoperative outcomes, particularly for patients undergoing major surgery.
Pros:
1) non-invasive
2) functional capacity
3) risk strat
4)
cons
1) complex
2) pt limitation
3) resource intensive
This question tested an understanding of the principles and limitations of commonly used pre- operative cardiac risk stratification tools
The candidates that did not achieve a pass generally described the screening tools without, again, evaluating their usage.
Poor answers also provided insufficient information or simply generic comments on the screening tools.
Better answers were able to provide advantages and disadvantages of each modality and link these with evidence, and
mentioned the importance of background risk factors and the extent and duration of surgery as influencing perioperative cardiac risk.
GENERAL – ECG after LBO Laparotomy (inferior ischaemia)
[21A05]
Standard 12-lead electrocardiogram (ECG) of a 56-year-old man in the post-anaesthesia care unit (PACU) two hours after an emergency laparotomy for bowel obstruction (ischemic changes). He is complaining of shortness of breath, abdominal pain and has a blood pressure of 160/110mmHg.
He has a history of hypertension controlled with atenolol and hydrochlorothiazide.
No preop to compare to.
Interpret this ECG and outline the appropriate management of this patient in PACU.
Pass rate 66.8%
ECG
1. TWI II III aVF –> INF
2. STD V5 V6 –> LAT
Inferior STEMI - block of
1. Dominant RCA (80%)
2. Dominant LCx (18%)
Mx - MOAN
1. M - morphine 5mg IV
2. O2 aim > 94%
3. Aspirin
4. N - GTN
HYPERTENSIVE
GTN / b blocker
Immediate post op
Thrombolysis LESS appro
(66.8%) This PACU clinical scenario question was reasonably well answered. As a minimum the candidate was required to: - correctly identify myocardial ischaemia and the territory affected
- Provide analgesia
- Ensure adequate oxygen saturation/oxygenation
- organise appropriate investigations including haemoglobin and troponin
- seek cardiology advice
- institute or consider therapies (e.g.: GTN antiplatelet therapy, b-blocker, clonidine)
General comments:
- Good answers addressed the specific scenario presented. For example, discussion of blood pressure management, acknowledging that
the patient was currently hypertensive, allowed a more comprehensive and nuanced approach to treatment and goals.
- Candidates scoring less well tended to provide generic non-specific answers that didn’t address the patient and situation in question.
- ECG interpretation was difficult for some candidates with several candidates identifying correct features of the ECG but failing to attach
the significance or the meaning of these changes in this patient.
- One reason for candidates scoring poorly was suggesting thrombolysis for this post laparotomy patient without any discussion of the
potential drawbacks of this approach or without the need to involve the surgeons in this decision making. This was considered a safety issue by the examiners and was marked accordingly.
PPM / AICD
[22B08]
A patient presenting for surgery has a DDDR pacemaker.
a) Explain the NASPE/BPEG Generic (NBG) pacemaker classification system.
b) Describe the assessment and preoperative management of this DDDR device. *NASPE/BPEG - North American Society of Pacing and Electrophysiology/British Pacing and Electrophysiology Group. Pass rate 73.3%
[10B07] (a) Describe the common classification code for permanent pacemakers. (30%)
(b) Outline the principles involved in the perioperative management of patients with a permanent pacemaker. (70%)
PSAMM
pace
sense
action
programmability (rate mod)
antitachy (multisite)
minimise diathermy - use bipolar
MRI - MRI-safe and reprogram
Limit EMI
Reprogram MRI and ECT
Reinterrogate after MRI and ECT
What if:
Frequent monopolar and close to PPM/AICD
Pass rate 73.3%
This was a straightforward question about pacemakers and their preoperative assessment and management.
It was answered to a satisfactory standard by the majority of candidates.
Correct identification of the DDDR pacemaker was required followed by an assessment that included the underlying cardiac rhythm, degree of time paced, battery life and device response to a magnet.
Better answers included a clear and organised preoperative management plan for the device which included consideration of the type and site of surgery and potential diathermy use.
A discussion on general patient preoperative cardiovascular assessment was not required in an answer to this question.
https://files.cdn.thinkific.com/file_uploads/500597/attachments/9ae/db4/7d4/Practice_Advisory_for_the_Perioperative_Management_of_Patients_with_Cardiac_Implantable_Electronic_Devices__Pacemakers_and_Implantable_Cardioverter%E2%80%93Defibrillators_2020.pdf
2021a A patient presents on the day of surgery with a blood pressure of 180/110mmHg. Justify your decision to proceed with or postpone surgery for this patient.
Pass rate 25.5% (go ahead with the surgery!)
> 140/90
Expert opinion: Postponement of elective surgery in patients with arterial pressure exceeding 180mmHg systolic and/or 110mmHg diastolic.
BUT
Periop control more important
- HTN pt inc CVS lability
- post op hypo/hyper inc risk of MINS/CVE
- low threshold of IAL - aim within 20% baseline
- should be controlled prior to major surgery
- Surgical factors *
Pt factors
* 2* causes of HTN
- anxiety/pain/distress
- Preop reading - unlikely accurate representation of long-term BP control
- Do not defer based on single reading on admission –> ambulatory or GP for baseline
- W/H ACEi/ARB 24h prior if controlled
- Continue bb / CCB / HCTZ
Oxf Anaes P.116
2021a
A 77-year-old patient is admitted to hospital with a fractured neck of femur requiring total hip arthroplasty. Physical examination on admission reveals signs of congestive cardiac failure.
Outline how congestive cardiac failure influences the perioperative risk for this patient. (30%)
Discuss how the finding of congestive cardiac failure influences your perioperative management of this patient. (70%)
Pass rate 84.2%
congestive cardiac failure is an independent risk factor for mortality
- NHYA Class 4 is associated with ~ 67% peri-operative mortality in non-cardiac surgery
assessment of the severity and the cause of the congestive cardiac failure
timing of surgery must be balanced against optimisation of the patient
- Urgent surgery (e.g. hip #) warrants a pre-operative risk assessment (e.g. with RCRI) if the Hx/Ex suggest potential undx severe obstructive intracardiac abnormality, severe pHTN, or unstable CV condition (e.g. unstable angina, acute stroke)
Best practice is to perform hip # ORIF within 48 (ideally < 24h)
CCS
PERIOP MED (CVS) – Heart transplant
[20B01]
You are asked to assess and anaesthetise a 54-year-old patient for a laparoscopic cholecystectomy. They received a heart transplant ten years ago. Discuss the issues relevant for this patient. (also15B02)
The denervated heart and the altered response to anaesthesia and certain drugs required discussion, as did immune suppression and Ax of the pt’s current functional status.
Sometimes omitted from answers, but of significant importance, was the issue of the pneumoperitoneum required for this procedure and how that may compromise this patient.
**25% will have surgery w/I 2 years of transplant **
1. Changes in physiology post-transplant:
1. Denervation ® no sensory, SNS or PNS innervation, delayed sympathetic response to circulating catecholamines
- Higher resting HR ® 90-110bpm 2’ vagal denervation
- Preload dependent cardiac output ® no SNS mediated BRR
- ECG ® 2 p waves, AF/AFL and RBBB common
- Dysrhythmias & conduction abnormalities ® PPM in 5%
- Silent ischaemia ® most common cause of death beyond 1st year (50% have atheroma on angiography by 5 years)
2. Changes in pharmacologic effect of cardiac drugs:
a) ineffective indirect
Atropine
b) Intact direct
Adenosine / Adr / NAd
3. Immunosuppression
- HTN/nephrotox/BM supp/hepatotx
4. Comorbidity
HTN 90%
DM
Renal
Cancer
5. Steroids - req stress dose
6. Allograft fx
- rejection
- arrhythmia
IMMUNOSUPPRESSION
1) calcineurin inh - cyclo/tacro
2) purine syn inh - azathioprine/MMF
3) T-cell dependent
CTAM - cyclo/tacro/aza/MMF
(61.6%) This q was generally well answered with the majority of candidates demonstrating they were familiar with the implications of a patient having had a heart transplant.
The denervated heart and the altered response to anaesthesia and certain drugs required discussion, as did immune suppression and Ax of the pt’s current functional status.
Sometimes omitted from answers, but of significant importance, was the issue of the pneumoperitoneum required for this procedure and how that may compromise this patient..
Anaesthesia for a pt with cardiac
transplant (BMJ 2002)
PERIOP MED (CVS) – Systolic murmur
[13A11] A 25-year-old male scheduled for elective surgery is found to have a systolic murmur on the day of surgery
a) What are the clinical features and ECG findings in this pt that would prompt you to postpone the case to allow further investigation? (70%)
b) What are the likely causes of this murmur? (30%)
AS/MR/TR/PS
- Timing
- Mid
- Pan - Nature
- Low pitch
- High pitch - Radiation
- Carotid - AS
- Ax- MR - Maneouvers
- Valsalva
- Squatting
- Hand grip - Symptoms
- Dyspnoea
- Ex limit
- chest pain - ECG
- LVH
- Arrhythmia
Cause of systolic murmur:
1. Pan-systloic
- MR
- TR
2. Mid-systolic
* AS/PR/GCM
OK flow murmur
PERIOP MED (CVS) – Mitral stenosis
[20A10] Outline your perioperative management of a patient with mitral stenosis scheduled for a laparoscopic inguinal hernia repair.
Aetiology
- F > M
- Pregnancy - MC
- Rheumatic fever
Classify/severity:
MG (mmHg) 5 / 10
MVA( cm2) 1.5 / 1. 0
(78.1%) The management of a significant valvular lesion during non-cardiac surgery is a core topic and the majority of candidates answered this question to the examiners’ satisfaction.
PERIOP MED (CVS) – Peri-operative anticoagulation for AF
[21A14] Discuss the options for anticoagulation MNG in the perioperative period for a patient taking warfarin for AF who requires a laparotomy for ischaemic bowel. (also 14A04)
Pre/Intra/post
bleeding vs embolus
Warfarin reversal
re-establishing anticoag
AF –> TIA/CVA
CHAD2S2-Vasc
PERIOP MED (CVS) – Peri-operative anticoagulation for PE (& tx surgery)
[19B11] A patient on an organ transplantation waiting list is taking rivaroxaban for recurrent pulmonary emboli. Discuss your perioperative anticoagulation plan. (? For the organ transplant vs. ? for another operation).
PERIOP MED (CVS) – Aortic stenosis
[12B04]
a) What is the natural history of aortic stenosis? (30%)
b) What are the key echocardiographic features in haemodynamically significant aortic stenosis? (70%)
Natural Hx -
Causes
- Calcific
- Congen
[ 10B07 ]
(a) Describe the common classification code for permanent pacemakers. (30%)
(b) Outline the principles involved in the perioperative management of patients with a permanent pacemaker. (70%)
PSA (PSR) PM
1. position
2. sense
3. action (response)
- programmability
- Multisite pacing
Magnet = asynch pacing mode
A/V/D OO
PERIOP MED (CVS) – Antiplatelets in IHD
[16B13] A 70-year-old man scheduled for major surgery presents to PAC. He has a history of ischaemic heart disease and coronary stent insertion and is on aspirin and clopidogrel. Outline the considerations when managing his antiplatelet therapy. (also 12B02, 04B05)
(67.8%) The borderline candidate should demonstrate an understanding that the key to this question is the assessment of risk, not management. Issues are (1) why manage? (2) what stent? (3) when was it placed and (4) what is the surgery date?
- MACE risk
- RCRI/NSQIP - thrombosis risk w/o DAPT
- BMS vs DES - bleeding risk with DAPT
PERIOP MED (CVS) - IACD
[20A09] A patient with an implantable cardioverter defibrillator pacemaker is scheduled for a left mastectomy. Discuss how the presence of this device affects your management of this patient. (also 08A10)
Indication:
1. VF/VT
2. NYHA2/3 OR DCM + EF <35%
3. AMI + EF <30%
4. LQTs
5. Brugada
Position
1. Defib (shock) chamber
2. Antitachycardia chamber
3. Tachycardia detec
4. Anti brachycardia chamber
Key
1. EMI
- possibility - disable
- diathermy –>
>15cm away
bipolar > monoploar
place pad far
short irregular burst only
Elective - device technician to turn off
Paeds Fontan vs Repaired adult Fontan
OBSTETRICS – FONTAN CIRCULATION
[19A12] A 30-year-old woman who is 28 weeks pregnant has been referred to your tertiary high-risk obstetric clinic. She has complex cyanotic heart disease and now functions with a Fontan circulation.
- How would you stratify her cardiovascular risk? (30%)
- What are the relevant anaesthetic issues for this patient? (70%)
[14B08] Essentially same question
complex hear disease, biventricular repair impossible
multistage
- modified BT shunt - SubClav to PA
- SVC + R PA joined (Glenn)
(BT shunt down) - IVC and R PA joined
*bypass R heart
*CO dependent of PBF
Goals
1. Avoid hypovol, use fluid - PRELOAD dependent
- Keep PVR low
- avoid low O2, pH, high CO2 - Keep ITP low
- SV, min PEEP, low Pinsp - Avoid myocardial depression
Complications
1. *Poor ventricular
2. *VTE events
3. *Conduction disturbances
- AF
4. Peripheral oedema
5. *Protein losing enteropathy
Arrhythmia + VTE + protein + LV dysfx
PALV
SIMS P. 386 + TP
PERIOP MED (CVS) – Eisenmenger syndrome
Also PAEDS
[19B09] A 25-year-old male is scheduled for an elective inguinal hernia repair. He has a ventricular septal defect and was
recently diagnosed with Eisenmenger syndrome. Discuss your preoperative assessment and how this affects your anaesthetic plan.
(55%)
PHTN with reversed central shunt
(VSD ASD)
L-R shunt + inc PBF ==> inc PVR ==> PHTN ==>
R-L shunt + cyanosis
Pre-op
Assess severity!
1. Fx status
- NYHA (adult)
- ADL/METS
- FTT/poor feeding
2. Clinical signs
- Tachycardia
- Tachypnoea
- Gallop S3/S$
- Heptomegaly
3. Echo
- shunt
- PHTN
4. Catheter results
Intraop
1. Avoid inc PVR
- avoid low O2 (HPV), pH, high CO2
OHA p67, p290
PERIOP MED (CVS) – Systolic murmur
[13A11] A 25-year-old male scheduled for elective surgery is found to have a systolic murmur on the day of surgery
a) What are the clinical features and ECG findings in this pt that would prompt you to postpone the case to allow further investigation? (70%)
b) What are the likely causes of this murmur? (30%)
Timing
- mid - AS
- pan - MR
Nature
Radiation
- carotid ~ AV
- axillae ~ MR
Exacerbation maneouvers
Symptoms
- dyspnoea
- Exercise limitations
- Chest pain
ECG
1. LVH
- LAD
2. Arrhythmia
- AF/SVT/WPW
3. Ischaemia
- STD/STE/TWI
Cause of systolic murmur
1. PAN - MR/TR/ VSD
2. Mid - AS/PS
3. Late - MVP
PERIOP MED (CVS) – Aortic stenosis
[12B04] a) What is the natural history of aortic stenosis? (30%)
b) What are the key echocardiographic features in haemodynamically significant aortic stenosis? (70%)
a)
Natural hx
Onset
Time course
Description
b) Echo findings
1. Qualitative
- Quantitative
- valve area
- transvalve gradient
- assess diastolic dysfx
Summary of the AHA/ACC Guidelines 2024
STRENGTH of recomm
1 - strong B»>R (recom)
2a - mod B»_space;R (reasonable)
2b - weak B>=R (mb reasonabl)
3 - no ben B=R (NOT rec)
3 - harm R>B
Level of ev (LoE)
A = high qual >1RCT
B-R= mod qual >1RCT
B-NR = mod qual non RCT
C-LD = obs / reg study
C-EO = exp opinion
Elevated risk - surg+pt >1% MACE
- CV Risk index
COR 2a - known CVD for NCS, tool can estimate the risk of perioperative MACE
*Functional capacity
COR 2a - elevated risk NCS, structured ax (DASI) stratify risk of perioop CVE
*Frailty
COR 2a -
*Periop biomarker for risk strat
COR 2a - BNP
COR 2b - cTn
12 Lead ECG
2a - if known CAD, arrhythmia, PAD , CVD, structural heart dx in ELEVATED (>1%) risk surgery
Ax LV Fx
- COR 1 - new SOB/O/E = HF/?ventricular dysdx
CARDIAC – Intra-aortic balloon pump
[08B12] List the indications and contra-indications for the use of an intra-aortic balloon pump.
Describe how its performance is optimised.
Ind:
1. AMI - card shock
2. Acute post MI MR
3. VS rupture
4. Refracy Vent arrhythmias
5. Failure to wean from CPB
6. Low CO post cardiac
CI:
ABSOLUTE - AAAs
1. AR
2. AoDiss or sig aortic aneurysm
3. Ao stent
Relative
1. severe PAD
2. Severe coagulopathy
3. Uncontrolled sepsis
Optimise performance:
1: Position - desc TA, tip @ carina
2. Volume - 25-50mL
3. Timing -
4. Rhythm -
5. Assist ratio - 1:higher when weaning
6. HR - augment @ diastole –> slower better
7. Aortic compliance
PVT RAHC
Principles:
Inflation - mid T wave - onset diastole
Deflation - peak R wave - early systole
Early balloon inflation results in increased afterload
Late balloon inflation results in decreased diastolic augmentation
Early balloon deflation fails to decrease myocardial oxygen demand
Late balloon deflation increases afterload
Poor diastolic augmentation results in suboptimal coronary perfusion
https://derangedphysiology.com/main/cicm-fellowship-exam/past-papers/2022-paper-2-saqs/question-2#answer-anchor
CARDIAC – Remote ablation considerations
[21B13] A 55yo patient with atrial fibrillation requires GA in the cardiac catheter labarotory for electrophysiological (EP) study and catheter ablation. Discuss the principles of remote location anaesthesia relevant to this case.
General:
MAGER - monitor/assistance/geography/equipement/resus
Position
** Arms up ** –> BP inj
Radiation
- as low as reasonably achieved
- lead, non fluoro
Procedure:
1. Long
2. Non-stimulating
3. Immobility
4. Low TV
Problems:
1. Blood loss
2. VT/VF
3. Groin haematoma
4. Cardiac tamponade
5. Oesophageal damage
Anaesthetic plan
1. Standard + IAL + PNS
2. PIVC large + IDC
3. Sed vs GA
a) SVT - LA/sed
b) ETT
(53.8%) This question asked candidates to discuss the principles of remote location anaesthesia relevant to the scenario presented. In their answer candidates were required to include:
- general remote location issues
- radiation exposure
- discussion with the cardiologist - requirements/potential problems
- a sensible anaesthetic plan
There was a tendency for many candidates to write about generic remote location issues without linking them to this specific case, namely AF ablation in the cardiac catheter laboratory under general anaesthesia. These answers fell short of the required minimum standard. Of note radiation exposure was often not mentioned in answers.
CARDIAC – Cardioversion of AF
[17A14] You are asked to provide anaesthesia for cardioversion for a 60-year-old male with atrial fibrillation.
Which factors influence the success of the cardioversion, and a safe outcome?
Aetiology:
1. K ~ diuretics
2. Thyrotoxocosis
3. Meds - anticoagulate
(45.9%) Candidates need to mention factors affecting the success of cardioversion such as
duration,
aetiology of AF,
electrolytes and
medications.
An understanding of the safety of the procedure, including underlying
disease process,
anticoagulation and
conduct of the procedure should have been shown.
Answers needed to mention both success and safety.
CARDIAC – Ablation of accessory AV pathway
[14A02] An otherwise well 35-year-old woman is scheduled for ablation of an accessory atrioventricular pathway in the Cardiac Electrophysiology laboratory.
What are the implications for anaesthesia and how would you manage them?
Rx arrhythmias
- sedation supress SVT
- avoid VA for AVNRT
- GA for AF and VT (longer)
Procedure:
vein –> heart –> e-grams –> energy to endocardium (RF or cryo) –> ablate
Duration: 1-6hrs
Location: Remote/iso
Intraop compl
VASC: pseudoaneurysm, haematoma
Cardiac:
Emboic
Other
(55.3%) Key components of an answer for this question related to providing an
understanding of the main problems and
an approach to prevention and management.
As a minimum, mention of
likely duration of procedure,
location [isolated] and
possible intra- and post- procedural life threatening complications was expected.
CARDIAC – Deep hypothermic circulatory arrest DHCA
[19B01] Describe the rationale for the use of deep hypothermic circulatory arrest & outline the pathophysiological consequences of this technique.
DHCA - pround hypothermia for cerebral protection - CTS / NROS
Neuroprotection
Brain
2% TBW
** 20% TB VO2**
15-20% circ BV (high CMRO2)
Hypothermia = most importat mech of cerebral protection
Hypothermia
DECR CMRO2 5-7% per 1oC
(CMRO2 15% @ 15oC)
Normal 3.5mL/min/100g
Process
1. CPB est
2. Pt cooled to 18-20oC
3. Ice pack
4. DHCA safe for 30-45 mins
- > 45 min - brain inj
Pathophys
1. Coag
- plt dysfx
- factor dysdx
2. CVS
- brady
- J wave
- VF < 28oC
3. Neuro
- DECR CMRO2 5-7% per 1oC
(44.3%) Many candidates demonstrated that they had little or no knowledge of deep hypothermic circulatory arrest (DHCA), often confusing it with cardioplegia, ECMO, passive cooling post cardiac arrest or cardiopulmonary bypass.
To pass this question an answer was required to demonstrate an understanding that the rationale for the use of deep hypothermic circulatory arrest is cerebral protection and that there are pathophysiological consequences such as coagulopathy, arrhythmias and neurological issues.
The examiners recognise that this technique may not have been seen by many candidates, however the question could have been answered with the application of knowledge gained from clinical experience in cardiac anaesthesia and Primary Examination physiology.
CARDIAC – Weaning from CPB
[16B10] Outline the considerations for successful weaning from cardiopulmonary bypass after coronary artery graft surgery. (also 12B03)
WA3RMVP
Warm
A-B
Re-exp lung
Remove X clamp
Rate/Rhythm
Monitor
Vasopressor
Proceed
Checklist
A-F
Post CPB hypotension
PL / AL / contractility
PL - inade circ vol –> fluids/bleed/coag
AL - vasodil/vasopleg –> pressor
Contractility - pump fail/stunning –> inotrope
(71.1%) Borderline answer should mention:
- Re-institution of native circulation (stable HR/rhythm, adequate volume/MAP)
- Re-institution of native ventilation (lungs re-inflated and ventilating)
- Metabolic parameters noramlised (temperature, acid-base, ABGs, adequate Hb/Hct, coagulation)
CARDIAC – Pericardial effusion 6 weeks post cardiac surgery
[15A03] A patient who is 6 weeks post cardiac surgery has a pericardial effusion requiring treatment. a) Outline the symptoms and signs of this condition. (70%)
b) Which of these features would trigger an urgent intervention? (30%)
effusion vs tamponde
** HD compromise**
Stages
1. COmpensatory
2. Early - RH compress –> dec VR
3. Late - obs shock
Sx
Beck’s triad
Pulsus paradoxus = > 10mmHg drop in sBP
Goal
1. Drain prior GA
2. SV - avoid PPV
3. HD - full/fast/contractility/SVR/SR
Mx
Preop
- monitoring + IAL + pressor
- defib ready
Intraop
- prepped/scrubbed
- perfusionist/CPB
- mRSI + ETTT (ketamine+VA+BZD/opioids)
- gentle ind to aim PL/AL/cont
- min MV pressure (Inc Paw –> dec VR)
Postop
- ICU - keep I+V
- stunned myocardium - inotropes
- watch recurrence
(82.9%) Key responses to pass this question included
A. Demonstrates an understanding of the range of severity of presentation (not just the classic acute signs).
B. Recognises the symptoms and signs of acute / severe tamponade
[23A01] List the branches of the coronary arteries and the myocardial territories and structures they supply. Outline the electrocardiograph (ECG) leads that correspond to the blood supply.
Describe the ECG changes in a non-ST-elevation myocardial infarct (NSTEMI). Pass Rate 48.9%
Two main ECG patterns associated with NSTEACS:
** ST segment depression 2+ contiguous lead**
** T wave flattening or inversion**
** New LBBB**
ECG Changes in NSTEMI
In Non-ST-Elevation Myocardial Infarction (NSTEMI), ECG changes can be subtle and varied:
1. ST-segment depression: Most common finding, often seen in two or more contiguous leads
2. T-wave inversions: May be present in leads corresponding to the affected area
3. Transient ST-segment elevation: May occur but resolves quickly
4. ST-segment elevation in lead aVR: Can indicate left main coronary artery or proximal LAD occlusion
5. New left bundle branch block: May be seen in some cases
6. Normal ECG: In some cases, the ECG may appear normal despite ongoing myocardial ischemia
(Perplexity)
https://litfl.com/myocardial-ischaemia-ecg-library/
This applied anatomy question focused on knowledge required to recognise, localise and interpret ischaemic ECG changes.
Candidates were required to list the major coronary artery branches of the right and left main coronary arteries, and additionally at least one structure or myocardial territory per artery.
Correct ECG leads for anterior, inferior and lateral walls of the left ventricle were required, and a minimum of two features consistent with NSTEMI to obtain a pass.
Better answers included the coronary distribution overlap for ECG changes in the lateral and inferior walls.
ECG changes seen in NSTEMI were generally well answered.
