Critical Care Flashcards
What medications can worsen a myasthenia crisis?
macrolides, fluoroquinolone, aminoglycosides, magnesium, beta-blocker
What is the total IVIG dosage for myasthenia gravis treatment?
2g/kg in evenly divided doses over 2-5 days
What are the MRI findings in Guillain-Barré Syndrome (GBS)?
thickening around intrathecal spinal nerve roots and cauda equina or ocular and cranial nerve enhancement in MF variant
What volume indicates a high chance of self-induced lung injury (SILI)?
> 15ml/kg
What are the symptoms of serotonin syndrome?
myoclonus, GI symptoms (diarrhea, nausea), hyperreflexia
What are the key features of Neuroleptic Malignant Syndrome (NMS)?
CPK elevation, rigidity like Parkinson’s
What triggers malignant hyperthermia?
succinylcholine and halothane; genetic
What factors increase hypercapnia?
- Increased dead space while maintaining Ve
- Decreased VT while maintaining Ve
- Sedative medications in normal individuals
What determines paCO2?
- Oxygen consumption
- Respiratory Quotient (R)
- Fat 0.7; Protein 0.8; CHO (carbs) 1.0
What causes increased CO2 production?
- Increased metabolic rate (sepsis, thyrotoxicosis, fever, activity)
- Carbohydrate metabolism
What decreases alveolar ventilation?
- Decreased VT
- Increased VD/VT (dead space) with stable minute ventilation
- Rapid shallow breathing
What is the formula for paCO2?
PaCO2 = k x VCO2/VA
What are the effects of hypercapnia?
- Increased cerebral blood flow and increased ICP
- Decreased myocardial contractility
- Decreased diaphragmatic function
- Shift in O2Hb dissociation curve to the right
What is the central respiratory center?
medulla (respiratory pacer cells) influenced by pH, PaCO2, PaO2
What can decrease respiratory drive?
- Hypothyroidism
- Congenital issues
- Metabolic alkalosis
What is Ondine’s Curse?
impaired autonomic control of ventilation, intact when awake only
What are the respiratory patterns associated with strokes?
- Cluster or Biot respiration - irregular
- Cheyne-Stokes: HF, high altitude, can occur in neurologic disease
What is the impact of injury above C3 on respiration?
leads to ventilatory failure
What is Myasthenia gravis characterized by?
decremental response to repetitive stimulation
What are the treatments for Myasthenia gravis?
- Plasmapheresis
- IVIG
- Acetylcholinesterase inhibitors
- Immunoadsorption
- Azathioprine
- Thymectomy between puberty and 60 years
What characterizes respiratory muscle weakness?
- VC decreases in supine position
- RV decreases
- TLC decreases
- MIP decreases
- Hypercapnia when strength <40% pred
What is Obesity Hypoventilation Syndrome (OHS)?
BMI >30, PaCO2 >45 while awake
What is the SpO2/Fio2 ratio for ARDS according to Berlin criteria?
SpO2: Fio2 <315
What are the causes of hypoxemic respiratory failure in ARDS?
- Failure of hypoxic vasoconstriction - shunting
- Disruption of surfactant
- Volutrauma
- Atelectrauma
- Biotrauma
What is the ideal body weight calculation for men?
50kg + 1.9 kg for every inch above 5 ft
What is the PROSEVA trial about?
Prone positioning >16h/d lowers mortality, better vent-free days
What are the risks associated with dopamine in shock management?
increased risk of harm compared to norepinephrine
What is the recommended management for extubation failure risk factors?
- Poor cough
- Heavy secretions
- Inability to perform all 4 tasks
What is the CAM-ICU used for?
confusion assessment method for the ICU
What is the definition of status epilepticus?
> 5 minutes continuous clinical or EEG seizure activity or recurrent seizures without recovery
What medications are used for status epilepticus?
- Benzodiazepines (Ativan IV, Midazolam IM, Rectal Diazepam)
- Follow with Fosphenytoin, Valproate, Levetiracetam
What is the depth of chest compressions during CPR?
> 5 cm (over 2 in)
What is the recommended rate of chest compressions during CPR?
100-120 per minute
What does the NEWS score indicate?
a high risk patient if 7 or more
What is the principle of fluid responsiveness assessment using passive leg raise?
increase in VTI or SBP; or reduction in PPV
What are common risk factors for delirium in critical care?
- Hypertension
- Alcoholism
- Dementia
- Admission severity of illness
- Benzodiazepines
What is the recommended approach for sedation in critical care?
Analgesia first, opioid to start
What is the significance of the A2F Bundle?
decreases likelihood of hospital death in 7 days; reduces delirium & coma; reduces physical restraint use
