Clinical Aspects

Question 1

What is the immediate management post cardiac arrest?

Answer 1

A - intubate and use capnography
B - ventilate, maintaining stats 94-98% and normocapnia
C - 12 lead ecg, reliable IV access, aim SBP > 100mmHg, fluid to restore normovolaemia, vasopressors/into ropes as indicated
D - avoid hyperthermia, sedate, control shivering. If short arrest and cerebral function returns quickly then may not need intubating.

Question 2

What diagnostics should occur post cardiac arrest?

Answer 2

Likey cardiac cause - if yes and STE on ecg then pci; if no STE then consider pci. If not cardiac lesion identified then CTB/CTPA
If cardiac cause unlikely then CTB +/- CTPA

Question 3

What is the icu management of a patient post cardiac arrest?

Answer 3

• Prevent fever for at least 72 hours
• maintain normoxia and normocapnia
• avoid hypotension
• echo
• maintain normoglycaemia
• diagnose and treat seizures
• delay prognostication for at least 72 hours

Question 4

What anti-epileptics should be used for seizures post arrest?

Answer 4

Keppra, valproate, and phenytoin have equal effectiveness but phenytoin causes more hypotension

Question 5

What are the guidelines for neuroprognostication?

Answer 5

In a comatose patient with a motor score of 3 or less and more than 72 hours, in the absence of confounders, poor outcome is likely when 2 or more of the following predictors are present:

• no pupillary and corneal reflexes at 72+ hours
• bilaterally absent N20 SSEPs at 24+ hours
• highly malignant eeg (suppressed background or burst suppression) at > 24 hours
• NSE > 60 at 48 and/or 72 hours
• diffuse and extensive anoxic injury on brain ct/mri

Question 6

Summarise TTM 2

Answer 6

NEJM 2021
Does targeted temp management in OOHCA impact all-cause mortality?
Randomised in ED if M4 max 180 mins post arrest; temp 33 degrees vs normothermia (cooled if temp > 37.8)
Both groups had normothermia maintained for 72 hours after initial 28 hour intervention period
Outcome - no difference in all cause mortality at 6 months, no difference in secondary outcomes (functional outcome/health related quality of life). Higher adverse events in hypothermic group - arrhythmias and haemodynamic instability. No difference in sepsis, pneumonia, bleeding.

Question 7

Summarise TTM trials post cardiac arrest

Answer 7

1. HACA trial in 2002 reported favourable outcome with therapeutic hypothermia post VF arrest - however it was small and evidence was of low certainty. Several in the Control group also developed fever so it was unclear if the benefits were from the avoidance of fever or due to the hypothermia
2. The TTM trial compared 33 vs 36 and found no difference in mortality.
3. The Hyperion trial showed that in patients following a non-shockable cardiac arrest the use of moderate hypothermia improved neurological outcome at 90 days

Question 8

What is delirium?

Answer 8

An acute change in consciousness and awareness that fluctuates over time. Patients may have disordered thinking, reduced attention, abnormal sleep/wake cycle, abnormal psychomotor activity, abnormal perceptions, abnormal emotional behaviour.

Question 9

What is the incidence of delirium in icu?

Answer 9

29%

Question 10

What is the usual duration of delirium?

Answer 10

Onset usually within 2 days and median duration 2-3 days (IQR 2-7 days)
Exceptionally it can last a lot longer and rarely never resolves

Question 11

What are the risk factors for delirium?

Answer 11

Predisposing risk factors - older age, alcohol abuse, pre-existing cognitive impairment, pre-existing hypertension
Precipitating risk factors - severe illness, coma, sedatives (bentos increase risk in a dose dependent manner), opioids, anti-cholinergic drugs, mechanical ventilation, lack of daylight, increased noise, open bay

Question 12

What is portal hypertension?

Answer 12

A pathological increase in portal vein pressure
Diagnosed when the hepatic venous pressure gradient (HVPG) is above the normal range (1-5mmHg)
When HVPG is 10 or more then ascites, HRS, HE and bleeding varices occur

Question 13

What is frailty?

Answer 13

Age related accumulation of molecular, cellular and tissue damage that leads to multi system dysregulation, functional decline and disproportionately poor response to physiologic stress.

Question 14

What is the physical phenotype of frailty?

Answer 14

Weight loss
Decreased walking speed
Decreased physical activity
Decreased grip strength
Exhaustion

Question 15

What are the mechanisms of frailty syndrome?

Answer 15

Metabolic dyesregulation - mitochondrial dysfunction, insulin resistance
Hormonal imbalance - reduced DHEA, testosterone, IDF 1, vitamin d; increased cortisol and obestatin
Haematological abnormalities - increased fibrinogen, ha-tog login and transferrin; decreased Hb
Endothelial dysfunction - increased ADMA

Chronic disease and Co-morbidity

Cellular senescence, oxidative stress, chronic inflammation

Environment and behaviour - proinflammatory diet, malnutrition, smoking, sedentary lifestyle

Phenotypic changes - sarcopenia, decreased strength, decreased functional capacity, decreased appetite, decreased metabolic rate, decreased weight

Question 16

How do you measure frailty?

Answer 16

Most common measure is the clinical frailty score - designed to assess frailty according to physical activity, functional status, chronic illness burden and cognition
Score ranges from 1-9
1-3 are considered non frail, 4 is prefrail, 5-8 are considered frail and 9 indicates terminal illness

Question 17

How do frail patients admitted to icu differ from non-frail patients?

Answer 17

More comorbidities
More likely to be disabled
Less likely to be admitted from home
Generally older
Each of these likely contributes to poorer outcomes in the icu