ITE Knowledge gaps 2023
Brainstem reflexes and brain death?
Brainstem death criteria
- Persistent Coma
- Absent verbal, movement, eye response to pain (e.g. GCS 3)
- Absent brainstem reflexes
- Many types
- Cannot breath without assistance
- Over 10min: No breaths OR PaCO2 increase >20mmHg
:::warning Must satisfy all 3 criteria :::
Imaging findings consistent with brain death
- CTA - Considered best
- CT Scan look for:
- Loss of grey white matter differentiation
- Diffuse Edema
- Effacement of Sulcus/Ventricle/basilar cistern
Other ancillary testing
- MRA
- Transcranial doppler
- EEG
- SSEP/MEP
Opiates
Which metabolite of Hydromorphone will accumulate in renal insufficiency and may cause neuroexcitation and cognitive impairment?
:::spoiler Hydromorphone-3-glucoronide (H3G) :::
Hepatic opiate metabolism
::: info Goal: make drugs more hydrophillic (e.g. acetylation, glucuronidation) Why: Renal excretion typically follows hepatic modification :::
Metabolism Phases
- Phase 1: Oxidation or hydrolysis via P450 system
- Phase 2: Conjugation
- Phase 1 usually preceeds phase 2 but not always
:::warning Main players: CYP3A4 and CYP2D6 :::
ESRD and Opiates
What happens if :no_entry_sign: beans
| Safest | Use with caution | Avoided |
|---|---|---|
| Fentanyl | Hydromorphone | Morphine |
| Sufentanil | Oxycodone | Hydrocodone |
| Remifentanil | Meperidine | |
| Methadone | Codeine |
::: warning
- most commonly encountered Main culprits: M3G, H3G, Normaperidine :::
Opiate neuroexcitation symptoms
- Agitation
- Confusion
- Hallucinations
- Myoclonus
- Seizures
Drugs that attenuate hypoxic pulmonary vasoconstriction
:::spoiler Ace-I, CCB, nitrates, prostacyclin, GA (volatile > IV) :::
Why does :arrow_up: BMI = :arrow_up: succinylcholine resistance
:::spoiler
- Increased butyrcholinesterase (pseudocholinesterase) activity :::
Pseudocholinesterase deficiency
Slows metabolism of:
- Succinylcholine
- Remifentanil
- Mivacurium
- Procaine/Cocaine
- Heroin
:::success Think: very short acting drugs :::
Cardiac symptoms during ECT
- Incrases in HR or BP are normal, (can also see bradycardia)
How does hypoalbuminemia cause alkalosis
:::spoiler
- Albumin is a weak acid :::
Strong ions, Strong ion difference (SID)
