Important F1 Concepts Flashcards
When is arterial blood gas (ABG) useful and what information does it provide?
Arterial blood gas is useful in any patient with a respiratory issue as it provides accurate readings of pO2 and pCO2.
pO2 is dependent on the FiO2. In healthy patients, the pO2 should be about 10 kPa less than the FiO2 (e.g., a patient on a 40% Venturi Mask should have a pO2 of around 30 kPa).
When is venous blood gas (VBG) useful and what additional information can it provide?
Venous blood gas is useful for situations where a rapid result is necessary (e.g., lactate, haemoglobin, sodium, potassium, calcium, pH).
Bicarbonate acts as a buffer for metabolic acids, and in acute metabolic acidosis, bicarbonate will be low.
Chronic CO2 retainers can be identified by a significantly raised bicarbonate level, indicating renal compensation by increasing bicarbonate reabsorption.
What is the difference between CPAP and BiPAP in Non-Invasive Ventilation (NIV)?
Non-Invasive Ventilation (NIV): Increases alveolar surface area participating in gas exchange.
CPAP (Continuous Positive Airway Pressure):
Used in type I respiratory failure.
Delivers a fixed pressure throughout both inspiration and expiration (IPAP = EPAP).
Holds open collapsing airways to facilitate gas exchange.
BiPAP (Bilevel Positive Airway Pressure):
Used in type II respiratory failure.
Delivers a higher pressure during inspiration (IPAP) and a lower pressure during expiration (EPAP).
The drop in pressure during expiration helps remove carbon dioxide from the body.
What is heart failure and what are its main consequences?
Heart failure is defined as the inability of the heart to pump sufficiently to meet the demands of the body.
Consequences include:
Reduced output, leading to shock and acute kidney injury (AKI).
Backlog of fluid into the peripheral and pulmonary circulation, resulting in peripheral oedema and pulmonary oedema.
What is the difference between Heart Failure with Reduced Ejection Fraction (HFrEF) and Heart Failure with Preserved Ejection Fraction (HFpEF)?
HFrEF:
Defined as heart failure with an ejection fraction of less than 40%.
Caused by inadequate emptying of the ventricles.
Prognostic benefit from ACE inhibitors, beta-blockers, and spironolactone.
HFpEF:
Defined as heart failure with an ejection fraction of greater than 50%.
Caused by inadequate filling of the ventricles due to stiffening of the myocardium.
No drugs provide prognostic benefit; treatment focuses on symptomatic management with diuretics.
Which critical drugs cannot be omitted?
Parkinson’s Disease medications.
Antiepileptics.
Antiretrovirals.
Long-term steroids.
What are the alternative routes for administering critical medications to patients who are nil by mouth?
NG Tube.
Parenteral Route (e.g., IV).
Transdermal Route.
What is Virchow’s Triad and how does it relate to clot formation?
Virchow’s Triad consists of three factors that contribute to clot formation:
Stasis: Example - Deep Vein Thrombosis (DVT) primarily forms due to stasis, leading to coagulation factor activation. Anticoagulants are used to treat DVT.
Vessel Wall Injury: Example - Myocardial Infarction (MI) is caused by vessel wall injury due to atherosclerotic plaque rupture, leading to platelet activation and clot formation. Antiplatelets (e.g., aspirin) are used to treat MI.
Hypercoagulability: An inherent or acquired condition that increases the risk of thrombosis.
What are the key considerations for using heparins in VTE prophylaxis and treatment?
Low Molecular Weight Heparin (LMWH):
Mainstay of inpatient VTE prophylaxis.
Should be avoided in patients with poor renal function.
Unfractionated Heparin:
Has a short half-life and can be rapidly reversed.
Useful in patients with renal impairment.
Requires APTT ratio monitoring for VTE treatment.
What are the considerations for using Direct Oral Anticoagulants (DOACs)?
DOACs do not require monitoring but should be avoided in renal impairment.
Apixaban: Taken twice daily.
Rivaroxaban: Taken once daily.
May not be appropriate for patients at extremes of body weight.
What are the benefits and specific uses of warfarin?
Useful for patients at the extremes of body weight due to close monitoring and adjustment.
Used for patients with atrial fibrillation associated with moderate to severe mitral stenosis and patients with mechanical heart valves.
What are the three main aspects to managing alcohol excess?
Chlordiazepoxide Reducing Regime: Managed using the CIWA scoring system.
Pabrinex: Administer 2 pairs TDS (three times daily) for 3 days.
Blood Tests: Focus on liver synthetic function.
What is the purpose of the Chlordiazepoxide reducing regime in managing alcohol excess?
To safely manage and reduce alcohol withdrawal symptoms.
Uses the CIWA (Clinical Institute Withdrawal Assessment) scoring system to determine the appropriate dosage.
What are the diagnostic and management steps for ascites?
Diagnostic:
SAAG (Serum-Ascites Albumin Gradient)
Neutrophil count
Management:
Ascitic drain
Manage post-paracentesis circulatory dysfunction with Human Albumin Solution (HAS)
Prevent reaccumulation with Spironolactone or Furosemide
What are the treatment options for hepatic encephalopathy and coagulopathy?
Hepatic Encephalopathy:
Lactulose and Rifaximin to reduce absorption of nitrogenous products
Coagulopathy:
OGD (Oesophagogastroduodenoscopy)
Vitamin K
