Neuro - Sedation / Delirium Flashcards
Mechanism of PRIS
Impaired oxidative phosporylation of the mitochondria
Free fatty acid utilisation
Features of PRIS
Met acidosis Arrhythmias (Brady) High lipids Renal and hep failure Rhabdo
Risk factors for PRIS
Young age Head injury Sepsis High catecholamine level High glucocorticoid levels Low carb/high lipid intake
Propofol dose to prevent PRIS
4mg/kg/hour
Potential monitoring for PRIS
Daily CK
Triglycerides
Evidence for dexmed
Is non-inferior to all usual sedative
Reduced delirium compared to lorazepam (MENDS study) and Midaz (MIDEX study)
No difference in MV duration compared to propo (PRODEX study)
Patients can communicate pain better compared to prop and midaz
Can dexmed be used for deep sedation
No
Ketamine side effects in ITU
Sympathetic stimulation
Bronchodilation
Preserved cough reflex
Muscle rigidity
Hallucinations
Delirium definition
Acute onset
Fluctuating mental stage and
Disorganised thinking
OR
Altered level of conciousness
Types of delerium
Hyperactive (agitated, restless, paranoid)
Hypoactive (lethargic, inattentive, “pleasantly confused”)
Mixed (fluctuate between two)
Which is the least common form of delirium
Hyperactive…
Incidence of deliriu
As high as 83%
Effects of delirium
Increased hospital LOS
Increased 6/12 month mortality
Neurocognitive issues in survivors
Is there a role for prophylactic antipsychotics in delirium
No
What is the scoring system for RASS, what is normal?
+4 to -5
+4 combative
-5 Unrousable
0 normal
Scoring system for Ramsey scale
1 - 6
2 is co-operative
1 anxious/agitation
6 unrousable
Scoring system fro Ryker
1-7
1 unrousable
7 dangerous agitation
4 calm
Propofol mechanism
Potentiates the inhibitory transmitters glycine & GABA which enhance spinal inhibition.
Hyperpolarisation –> chloride influx
Propofol PKs
Highly protein bounf 98% albumin
Fast onset/offset
High clearence
Accumulates in tissues
Propofol S/E
Decreased SVR
Decreased CO and BP
Resp depression
Antitussive
Adverse effect Propofol
PRIS
Pain on bolus
High lipids
Benzos mechanism
Enhancing effect of GABA at GABAa receptors
Benzos PK
Loraz - metabolised by glucuronidation to infactive metabolites
Midaz - oxidized by cP450 to water soluble metabolites (THESE ACCUMULATE)
Benzos PD
Dose dependent resp depresson
Decreased HR/SVR
Fentanyl potency compared to morphine
100
Alfentanil potenicy compared to fent
10
Remi mechanism
Selective mu agonst
Remi side effects
Brady/hypotension/rigidity of chest wall
Remi breakdown
Plasma esterases - context insensitive
Dexmed mechanism
Centrally acting alpha agonist agonist at the locus coerueus
A2 to A1 affinity is 1600:1
Active d-isomer of medotomidine
Dexmed PK
94% protein bound
Clonidine mechanism
Centrally acting a2 agonist at the reticular nucleus of the medulla
Increases intrracellular cAMP, increased potassiu
Alpha receptor stimulation in spinal cord leads to increased endogenous opiate release
A2:A1 200:1
Clonidine side effect
Hypertension (a1)
prior to hypotension (a2)
Brady
Rebound hyper on cessation
Ketamine mech
Non competitive NMDA receptor antagonist
Ket metab
Metab in liver to norketamine, conjugated to inactive metabolites –> urine
Examples of when deep sedation is needed
Procedures )trachy) Non physiological ventilation (inverse ratio) Proning Intracranial hypertension Seizures
Morphine metabolism
liver to morphine 3 and morphine 6 glucoronide
6 is potent analgesic
Excreted in urine
Which opiate has longest half life on infusion
Fentanyl (200mins after 6hours)
Duration of action is determined by redistribution rather than clearnece
How is duration of alfentanil determined
clearence rather than distribution (compare to fent)
Predictors of delerium
Male Increasing age Diseae severity Pre-existing dementia Structural brain damage Medication related cholinergic burden
Proportion of patients with hyperactive delirium
1%
Proportion of patients with hypoactive delirium
35%
Proportion of patients with mixed delirium
65%
Diagnostic criteria for delirum (DSM 4)
Acute onset and fluctuating
Inattention and disturbance of conciousness
Change in cognition
Pathophysioloigcal cause
how many parts to the Intensive Care Delirium screening cheklist
8, based on obs over a 24 hour period
Does the Intensive Care Delirium Screening Checklist (ICDSC) need patient co-operation
No
Which is more sensitive, ICDSC or CAM-ICU
CAM-ICU
Disadvantage with CAM ICU
Less specific
Higher false positive
Needs co-operation
Does not assess severity not sub-type
Benefit of epidural
Analgesia Decreased resp issues ?decreased mortality Less peri-op blood loss, DVT, arrhythmias Faster return to GI function ERAS - shorter length of stay
Disadvantages to epidural
Retention Itching n/v Hypotension poor/patcyh block
Catheter migrate to sub arach space Local anaesthetic tox Wrong site injection Nerve injury absess Verterbral can haematoma Spinal cord infarct
Disadvantage of daily sedation holds
Whilst LOS, MV etc reduce, the risk of unplanned self extubation is higher
Ideal RASS for tubed patietn
-1
Which GPRC are opiates providing analgesia and sedation
mu - analgesia
Kappa - sedation
