final frca teaching december 2020 festive crqs

Final FRCA TeachingDecember 2020Festive CRQs

OSA – Cardiovascular Consequences

• Overall increased risk of cardiovascular morbidity and mortality.

• Arrhythmias

• Hypertension

• Biventricular dysfunction

• Pulmonary hypertension

• Congestive heart failure

• Ischaemic Heart Disease, Angina, Myocardial infarction

• Risk increased by the increased presence of dyslipidaemia,

enhanced platelet activation, inflammatory pathway activation

and endothelial dysfunction seen in OSA

OSA – Intraoperative Management

• Target normal oxygen saturations

• Target normal end tidal carbon dioxide

• Use short-acting agents such as desflurane, propofol and remifentanil.

• Monitor neuromuscular blockade

• Ensure adequate reversal of NMB if used before extubation.

• Consider need for sugammadex.

• Extubate awake.

• Use multimodal analgesia to reduce/avoid need for long-acting opioid

• Consider a regional technique in combination with general anaesthesia

OSA – Preoptimisation

• Ensure patient is established on and compliant with CPAP for three months

prior to surgery, if clinical condition permits, and continue use in the

perioperative period.

• Encourage preoperative weight loss if overweight.

• Dietician referral if necessary.

• If a smoker, encourage to stop and refer for cessation therapies

• Assess for the possibility of associated difficult airway and plan accordingly.

• Consider the possibility of using regional technique only, or regional

technique as a method of reducing overall use of systemic drugs that will

impact on respiratory drive and alertness.

• Avoid sedative premedication.

Liver Disease

Functions of the Liver

• Carbohydrate metabolism: Gluconeogenesis, Glycogenesis, Glycogenolysis

• Protein metabolism and synthesis: Albumin, Prealbumin, Globulins

• Lipid metabolism: Cholesterol, HDL/LDL, Triglycerides/ketone bodies

• Metabolism of nitrogenous compounds: Recycling of ammonia

• Coagulation factor production (I, II, V, VII, IX, X and XI) and Antithrombin,

protein C and S

• Bile metabolism

• Drug biotransformation (1 mark for a specific function EG: hydrolysis)

• Storage: Vitamins (A, B12, D, E K), Iron, Copper, Glycogen

• Immunological function: Kupffer, Pitt

• Hormone synthesis: Insulin-like GF1, Thrombopoietin, Angiotensinogen

• Erythropoiesis (in the fetus until 32 weeks gestation)

Common Causes of Liver Failure

• Alcoholic liver disease.

• Non-alcoholic fatty liver disease (NASH) (caused by obesity, diabetes)

• Viral hepatitis, B and C.

Rarer Causes of Liver Failure

• Autoimmune disorders: primary biliary cholangitis, sclerosing cholangitis.

• Metabolic disease: Wilson’s, haemochromatosis, alpha-1-antitrypsin

deficiency.

• Toxins/drugs

• Right heart failure

Child-Pugh Score

• Based on population studies, an individual’s Child-Pugh category can be

used to predict their overall survival and their likely mortality associated

with abdominal surgery.

Child-Pugh Score

• Serum Albumin

• Ascites

• Bilirubin

• INR / Prothrombin Time

• Hepatic Encephalopathy

Mnemonic ABCDE

Albumin, Bilirubin, Clotting (INR), Distension (Ascites), Encephalopathy

Child-Pugh Score

Anaemia in Liver Disease

• Chronic blood loss from gastrointestinal tract

• Hypersplenism-induced haemolysis

• Anaemia of Chronic illness

• Malnutrition

Housefires

Inhalational Injury - History

• Burn/fire in an enclosed space.

• Loss of consciousness at the scene, possibly due to:

• Drugs

• Alcohol

• Head injury

• Hypoxia

• Carbon monoxide or hydrogen cyanide poisoning.

• Fatalities in the same incident increase the risk of significant injury

Inhalational Injury - Examination

• Voice changes (hoarseness)

• Cough

• Stridor

• Burns to the face, lips, tongue, mouth, pharynx, or nasal mucosa

• Soot in the sputum, nose, and mouth

• Respiratory distress

• Decreased level of consciousness, confusion or agitation

• Clinical hypoxaemia: SpO2 < 94% in air

• Increased carboxyhaemoglobin (COHb) levels

Inhalational Injury - Mechanisms

• Heat (thermal injury)

• Particulate matter deposition and respiratory irritants (chemical

injury)

• Asphyxiation and systemic toxicity

Inhalational Injury – Primary Survey

• Impending or actual airway obstruction

• Reduced level of consciousness

• Cardiac arrest

• Hypoventilation

Inhalational Injury – CO Poisoning

• Any new objective acute neurological signs

• EG: Increased muscle tone, up-going plantars

• Coma

• ECG evidence of ischaemia

• Clinically significant acidosis

• Initial COHb levels >30%

• Assuming carbon monoxide (CO) poisoning in all fire victims is prudent.

• Standard pulse oximetry will not distinguish COHb from deoxygenated or

oxygenated haemoglobin and so overestimates oxygen saturations.

• Low COHb levels in the emergency department do not exclude significant

CO exposure (high flow oxygen at the scene will cause rapid washout).

Inhalational Injury – CN Poisoning

• Lactate > 7 mmol/litre

• Elevated anion gap acidosis,

• Reduced arteriovenous oxygen gradient

• There is a risk of exposure to cyanide after smoke inhalation, particularly

from fires involving synthetic materials (e.g. furnishings, plastics, vinyl).

• Such patients are often hypoxic and exposed to carbon monoxide making

the diagnosis of cyanide toxicity more complicated.

• Cyanide (CN) levels are not readily available (only UK laboratory measuring

cyanide levels is in Cardiff), so treatment should not wait for levels.

• Features of toxicity include: Headache, confusion, convulsions, loss of

consciousness, fixed unreactive pupils, arrhythmias, myocardial ischaemia

and cardiovascular collapse.

Inhalational Injury – CN Poisoning

• Hydroxocobalamin – probably the safest choice

• Dicobalt Edetate

• Sodium Thiosulphate

Oral Anticoagulants

Oral Anticoagulants

• Warfarin: Inhibition of epoxide reductase

• Apixaban: Direct Inhibition of Factor Xa

• Rivaroxaban: Direct Inhibition of Factor Xa

• Dabigatran: Direct Inhibition of Factor IIa (thrombin)

Oral Anticoagulants

Purpose

Estimation of the risk of stroke in patients with atrial fibrillation

Relevance

It can be used to decide whether bridging therapy is needed or not

Oral Anticoagulants

Oral Anticoagulants

• Discontinue anticoagulant

• Supportive care - (IV fluids and blood products)

• Activated charcoal (if within 3 h of ingestion)

• Consider giving DOAC reversal agent

• Consider giving prothrombin complex concentrate (PCC) (useful for

rivaroxaban or apixaban only)

• Consider giving recombinant factor VIIa

• Consider giving tranexamic acid

Oral Anticoagulants

Regarding Warfarin

• PCC (Prothrombin Complex Concentrate) and Vitamin K

• FFP is not recommended for the reversal of the effects of warfarin.

• PCC has a relatively short duration of action (half-life of 6 h) so

vitamin K is essential to maintain the corrected coagulation profile if

haemostasis is desired after this 6 h window.

Oral Anticoagulants

Regarding dabigatran

• Consider dialysis for reversal

• Specific reversal agent: Idarucizumab (Praxbind®) – licensed agent

• It can rapidly, durably, and safely reverse the anticoagulant effect of

dabigatran

• There is no evidence of hypersensitivity reactions

• The full reversal dose is 5 g and costs £2400 in the UK

Oral Anticoagulants

Regarding apixaban and rivaroxaban

• Specific reversal agent: Andexanet – unlicensed agent

• It is a genetically engineered version of human factor Xa that binds

Xa inhibitors, but the active sites have been removed so it does not

interfere with coagulation.

• The terminal half-life is 1 h.

• To achieve a short duration of reversal (i.e. 1-2 hrs), a bolus may be

adequate

• For a sustained effect, an infusion should be administered

Oral Anticoagulants

Perioperative Steroids

• 100mg


• IV Hydrocortisone by infusion at 200 mg/24hrs


• Hydrocortisone 100 mg/24hrs by IV infusion

• Hydrocortisone 50 mg every 6 hrs by IM injection


• 10mg / day


• Volume-resistant hypotension

• Patient reports non-specific malaise

• Somnolence or obtunded conscious level

• Cognitive dysfunction.

• Orthostatic hypotension.

• Hyponatraemia

• C-reactive protein may be raised

• Persistent pyrexia


• Osteoporosis

• Hypertension

• Peptic ulcer disease

• Pancreatitis

• Central obesity

• Cataracts

• Thin skin with Increased likelihood of bruising

• Psychiatric disturbances – predominantly mania

final frca teaching december 2020 festive crqs

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