Intensive care medicine Flashcards
What is the AKIN Criteria?
- Stage 1
- ↑ Cr ≥ 26.5 μmol/L or ↑1.5-2x from baseline
- UO < 0.5 mL/kg/h for >6h
- Stage 2
- ↑ Cr 2-3x
- UO < 0.5 mL/kg/h for >12h
- Stage 3
- ↑ Cr >3x or if baseline Cr ≥353.6 μmol/L ↑Cr ≥ 44.2 μmol/L
- UO < 0.3 mL/kg/h for 24h / Anuria for 12h
Who can test for BSD?
Requires 2 medical practitioners:
- Substantive consultant
- Doctor with > 5 years GMC registration
What are the main types of RRT?
- Intermittent haemodialysis (IHD)
- Peritoneal Dialysis (PD)
- Continuous Haemofiltration (CVVHF)
- Continuous Haemodiafiltration (CVVHDF)
- Slow continuous ultrafiltration (SCUF)
What is the World Federation of Neurosurgeons classificartion of SAH?
- GCS 15, no motor deficit
- GCS 13-14, no motor deficit
- GCS 13-14, with motor deficit
- GCS 7-12, +/- motor deficit
- GCS 3-6, +/- motor deficit
When is death confirmed following ‘successful’ BSD testing?
Time of death recorded as the time of completion of the second set of tests
Describe the Oculo-vestibular reflex proceedure
- Check for drum perforation/ear wax
- Instill 50 ml of ice cold saline into external auditory meatus over 1 min
- Observe for eye movements
- Test both sides (inability to perform test on one side does not invalidate the test)
How many parameters does APACHE II have?
15 in total
- 2 background (age + chronic ill health)
- 13 Acute parameters
What are the immediate complications of SAH?
- Rupture
- Hydrocephalus
- Rebleed
- Vasospasm
What diseases is spontaneous pneumothorax associated with?
- Marfans
- Cystic fibrosis
- Pulmonary infarction
- Staphylococcus aureus pneumonia
Normal intra-abdominal pressure
- 0 or negative
- Mild elevation 5-7 mmHg seen post op, IPPV or obesity and is normal
What is the optimal ‘dose’ in CVVHF?
35 mL/Kg/hr
What is the mortality associated with APACHE II scores of 25 and >35 respectively?
- 25 = mortality of 50%
- > 35 = mortality of 80%.
Risk factors for SAH
- Female gender
- Smoker
- Family history
- Polycystic kidney disease
- Collagen disorder (e.g. Ehlers-Danlos/Marfans)
- Hypertension
- Alcohol consumption
Define Acute Kidney Injury
Abrupt reduction in renal function resulting is failure to maintain fluid, electrolyte and acid base homeostasis
Typical blood flow for haemofiltration
0-300mL/min
What are the risk factors for abdominal compartment syndrome?
- Decreased abdominal wall compliance
- Abdominal surgery/tight packing
- Major trauma/burns
- Proning
- Obesity
- Increased intra-luminal contents
- Ileus
- Bowel obstruction
- Increased intra-abdominal contents
- AAA
- Ascities
- Bleeding
- Capillary leak / Fluid resuscitation
- Sepsis
- Pancreatitis
- Massive fluid resuscitation
Propofol Infusion Syndrome - Risk Factors
- >4mg/kg/hr for 48 hours; but can occur at lower doses
- younger age
- acute neurological injury
- low carbohydrate intake
- catecholamine infusion
- corticosteroids infusion
Categorise ARDS Severity
- Mild (PaO2/FiO2 200-300), Mortality 27%
- Moderate (PaO2/FiO2 100-200), Mortality 32%
- Severe (PaO2/FiO2 < 100), Mortality 45%
What were the recommendations for insertion following the NCEPOD report “On the Right Trach”
- Consent and WHO checklists should be implemented
- Tube diameter and length should be appropriate to the patient, hence:
- Departments should have a wide supply availible
- Operators should be familiar with different models
- Placement should be confirmed by capnography
- Positioning should be confirmed by bronchoscopy
What are the components of the Berlin criteria?
- Acute (Onset less than 1 week)
- Bilateral opacities consistent with pulmonary oedema
- PF ratio less than 300mmHg with a minimum of 5 cmH20 PEEP (or CPAP)
- Non-cardiac origin
What are the anticoagulation options in CVVHF?
- Patient strategies
- Anticoagulation is unnecessary if INR > 1.5 or PLT are < 50
- Anticoagulation with heparin etc.
- Equipment
- Pre-dilution to decreased Hct
- Limiting filtration fraction < 30% by increasing the blood pump speed.
- Drug
- Heparin (aims to anticoagulate circuit only, but there is always some systemic effect)
- Citrate (watch for ↓Ca, ↓Na, alkalosis)
- Prostacyclin (potent vasodilator, typically reduces MAP by 15 mmHg)
- Lepiruden (useful in HIT)
Propofol Infusion Syndrome - ECG Features
- Brugada like pattern (coved type = convex-curved ST elevation in V1-V3)
- RBBB
- arrhythmia
- heart block
What is the correct proceedure for removing PPE?
- Gloves in the room
- Gown in the room
- Eye protection in the room
- Facemask removal outside of the room
What factors made PiCCO unreliable?
- Intracardiac shunts
- Aortic aneurysm
- Aortic stenosis
- Pneumonectomy
- Pulmonary embolus
- Balloon pumps
- Unstable arrhythmias
The role of citrate in RRT
Chelate calcium, preventing clotting in circuit
What are the conservative management options for abdominal compartment syndrome?
- Decompression (NG, flatus tube, enemas etc.)
- Drain ascites
- Offload with diuretics
- Reposition into supine/reverse trendellenburg
- Reduce all impedement to abdominal venous drainage
- Deepen sedation
- Relax abdominal muslces (NMB)
- Drive MAP with ionotropy
What are the APACHE II parameters?
- Age
- Basic Observations (all normal obs, GCS instead of SpO2):
- Temperature
- RR
- HR
- MAP
- GCS
- Blood Gas variables:
- Arterial pH
- AaDO2 / PaO2
- Na
- K
- FBC:
- Hct (Not Hb)
- WCC
- Renal F(x):
- Creatinine
Classification of Abdominal Compartment Syndrome
- Primary
- Primary pathology
- AAA, haemorrhage, pancreatitis, ischaemia
- Secondary
- Extra-abdominal pathology
- E.g. fluid resuscitation
- Tertiary
- Chronic
- PD, Ascites
What are the typical physiological changes post BSD?
- Respiratory
- Neurogenic pulmonary oedema
- Post BSD inflammatory change
- Cardiac
- Sympathetic surges (↑HR, ↑BP, ↑CO, ↑Myocardial ischaemia)
- Cushings response
- Loss of sympathic control
- Peripheral vasodilitation
- Endocrine
- ↓ADH => DI
- ↓T3 => hypothyroid
- ↓Cotisol => blunted stress response
- Hypothalamic failure => loss of thermoregulation
- Other
- Coagulopathy => release of thromboplastin
Why is PD a poor choice for ITU RRT?
- Poor solute clearance
- Refractory hyperkalaemia common
- Very slow
Mechanism of action for haemofiltration
Convection (solute drag) driven by hydrostatic pressure
Define ARDS.
An acute diffuse, inflammatory lung injury, leading to increased pulmonary vascular permeability, increased lung weight, and loss of aerated lung tissue with hypoxemia and bilateral radiographic opacities, associated with increased venous admixture, increased physiological dead space and decreased lung compliance.
What are the main benefits of using an acute scoring system?
- Comprehensive serial monitor of patients condition
- Audit of department
- Comparison against other units
- Stratification for research
What are the pre-conditions for brain stem death?
- Diagnosis compatible with BSD
- Apnoeic coma (GCS 3/15)
- No hypothermia: > 34°C
- No endocrine disturbance: Normal TFTs
- No metabolic distrurbance
- PaCO2 < 6, PaO2 > 10, pH 7.35-7.45
- Na+ 115-160
- K+ > 2
- Normal Gluc, Mg, Phos
- No abnormal seizure activity
- Evidence of adequate CNS perfusion: MAP > 60
- No residual sedation
- No NMB
On what principle is PiCCO based?
Stewart-Hamilton equation
Typical blood flow for haemodialysis
200-400mL/min
Relative Indications for RRT
- Metabolic Acidosis
- Endotoxaemia/Sepsis (contentious)
- Hepatic failure (hyperlactataemia)
- Rhabdomyolysis
What is the score range for APACHE II?
0 - 71
Define brain stem death
An irreversible loss of any capacity for consciousness coupled with the loss of ability to breath
What is the RIFLE criteria?
- Risk - 1.5x Cr, <0.5mL/kg/hr for 6 hrs
- Injury - 2x Cr, <0.5mL/kg/hr for 12 hrs
- Failure - 3x Cr, <0.3mL/kg/hr for 24 hrs
- Loss - 4 weeks ARF
- ESRF - RRT requirement for > 3 months
What were the organisational recommendations following the NCEPOD report “On the Right Trach”
- Tracheostomy insertion should be documented and coded as an operation
- ITUs need rapidly availible difficult airway trolleys
- Training programmes for managing difficult/blocked TTs should be set up
- Capnography should be availible and used at each bedspace
- Core competencies for trachy care should be set out by the trust
What particular therapies may be required following BSD to optimise for transplant
- Methylprednisolone
- T3
- Vasopressin
- Desmopressin
- Insulin
How do you perform indirect abdominal compartment pressure measurement
- Via bladder catheter
- Empty bladder
- Inject 50 mL into bladder and clamp
- Wait to settle
- Use sampling port to attach standard pressure transducer
- Measure at mid axillary line
- Measure at end expiration
Mechanism of action for dialysis
Diffusion
Describe the apnoea test
- Performed following CN examination
- Increase FIO2 to 1
- ABG and modify ventillation to reach PaCO2 = 6kPa, pH = 7.4 and SpO2 > 95%
- Maintain apnoeic oxygenation by instilling 5 litre/min with a suction catheter
- Observe for respiratory activity for 5 min
- Confirm an increase in PaCO2 of > 0.5 kPa on ABG
- After completion reconnect ventilator
- Normalise Acid–base status prior to 2nd test
What is the incidence of AKI in critical care patients?
30%
Propofol Infusion Syndrome - Clinical Features
- On propofol
- High dose proprofol infusion (maximum dose 4mg/kg/hr)
- Long duration of infusion
- Increasing inotrope support
- green urine (contentious)
- Cardiovascular collapse
What can PiCCO measure?
- CO/CI
- Global End Diastolic Volume (GEDV/GEDI)
- Intrathoracic blood volume (ITBV/ITBI)
- SVV
- EVLW
- SVRI
- Cardiac Function index
What are the possible ancillary tests to brain stem death testing in the UK?
- Absence of cerebral blood flow
- Four vessel angiography (gold standard)
- Transcranial doppler
- CT angiography (not validated)
- Absense of cerebral electrical activity
- Evoked potentials
- EEGs
Factors affecting solute transfer in CVVHF
- Solute (molecule size, charge, protein binding)
- NB larger molecules removed better by CVVHF
- Membrane (cellulose/synthetic, porosity, thickness, SA)
- Rate of solute delivery (blood flow)
- Consentration of diasylate (IHD) or Ultrafiltration Dose (CVVHF)
Optimal exchange rate for haemofiltration
35mL/kg/hr (about 2.4L/hr for a 70Kg Pt)
What is the APACHE II Score?
The Acute Physiology and Chronic Health Evaluation II Score. It is a severity of disease classification system.
What are the disadvantages of acute scoring systems?
- Certain specific diseases score highly even though they are not associated with such high mortality. E.g DKA and postoperative patients
- Non linear scales (i.e. 20 is not twice as sick as 10)
- Scores biased depending on when taken (i.e. during cardiac arrest, vs. following resuscitation)
Define abdominal compartment syndrome
Sustained intra-abdominal hypertension >20mmHg with evidence of end organ damage
Define Propofol Infusion Syndrome
A life-threatening condition characterised by acute refractory bradycardia progressing to asystole and one or more of:
- metabolic acidosis
- rhabdomyolysis
- hyperlipidaemia
- enlarged or fatty liver
How do you diagnosis ACS?
- Identify at risk groups (sepsis, maj. abdominal surgery, high fluid requirements, abdominal malignancy)
- Clinically
- Oliguria
- Acidosis
- Unexplained lactataemia
- Severe abdominal pain
- Increasing Vent. pressures
- Tense abdomen
- Direct / Indirect pressure measurement
What is the treatment algorithm for status epilepticus?
- Lorazepam 0.1 mg/kg
- Phenytoin (15 mg/kg at <50 mg/min) or phosphenytoin (15 mg/kg at 100-150 mg/min)
- Thiopental or propofol
Absolute indications for RRT
- Refractory volume overload
- Potassium > 6.5
- Drug elimination
- Symptomatic uraemia (>30mmol/L)
- Hyperthermia
What is PiCCO?
A cardiac output monitor that combines:
- Pulse contour analysis
- Transpulmonary thermodilution
Also includes continuous ScvO2 monitoring (CeVOX probe via standard CVC)
List the cranial nerves tested in BSD testing
- Olfactory - not tested
- Optic - pupillary response: sensory
- Occulomotor:
- Pupillary response: motor
- Oculovestibular reflex: motor
- Trochlear - Oculovestibular reflex: motor
- Trigeminal:
- Corneal reflex: sensory
- Response to pain: sensory
- Abducens - Oculovestibular reflex: motor
- Facial:
- Corneal reflex: motor
- Response to pain: motor
- Vestibulocochlear - Oculovestibular reflex: sensory
- Glossopharyngeal - gag reflex: sensory
- Vagus
- Gag reflex: motor
- Cough reflex: sensory and motor
- Accessory - not tested
- Hypoglossal - not tested
Contraindications to organ donation
- Absolute
- Known/Suspected CJD
- Active/Poorly controlled HIV
- Relative
- Disseminated malignancy
- Melanoma treated < 5 years ago
- Treated malignancy within 3 years
- Age > 90
- Active TB
- Severe untreated sepsis
Grades of intra-abdominal hypertension
- 12-15 mmHg
- 16-20 mmHg
- 21-25 mmHg
- >25 mmHg
What is SCUF?
- Slow continuous ultrafiltration
- Same principle as CVVHF, no replacement fluid
- Slow, minimal solute removal
Methods of anticoagulation in RRT
- Heparin
- Citrate
- LMWH
- Prostacyclin
- Predilution
Expected rate of rise of PaCO2 in Apneoa BSDT
0.4-0.8kPa/min
How is nitric oxide formed?
Synthesised from arginine in a reaction catalysed by nitric oxide synthase.