Cardiovascular

Abdominal aortic aneurysm

Definition

An abdominal aortic aneurysm (AAA) is defined as an enlargement of the aorta by at least 1.5 times its normal diameter. The normal diameter of the aorta is ~2?cm and increases with age. Most AAA are small and not dangerous; however when they increase in size, they are prone to rupture causing a life-threatening condition.

Epidemiology

It is estimated that in 95% of patients, AAA is a complication of atherosclerosis. Risk factors include being male, hypertension, increasing age, smoking and a family history of AAA.

History

• Asymptomatic and often detected on routine abdominal imaging or NHS screening programme.
• Patient may feel pulsatile mass in abdomen.
• Backache.
• Aching pain in the epigastrium and central abdomen to the back.
• In rupture the patient will have severe abdominal pain, often epigastric and radiating to the back.
• May be accompanied by collapse.
• Symptoms can be similar to renal colic.

Examination

The patient should be assessed using the ABCDE approach with appropriate step interventions. Specific points to increase the likely diagnosis of a ruptured AAA include:

• Signs of shock
• Abdominal tenderness and guarding
• Palpable abdominal mass - often pulsatile
• Weak or absent lower limb pulses

Investigations

• Bloods:
  • FBC
  • U&Es
  • LFTs
  • Clotting screen
  • Cross-match
• Arterial blood gas
• ECG
• CXR and AXR
• CT abdomen
• FAST ultrasound scan

Management

• Transfer direct to the emergency department (ED) with pre-alert.
• ABCDE approach.
• Oxygen (set SpO2 target).
• IV access?×?2.
• Cautious IV fluid resuscitation to maintain blood pressure (systolic?~90?mmHg or radial pulse presence), ideally with blood products.
• Analgesia.
• Early discussion with appropriate surgeons.
• Prepare for theatre.

Acute coronary syndrome

Definition

Acute coronary syndrome (ACS) is an umbrella term that encompasses:

• Unstable angina
• Non-ST segment elevation myocardial infarction (NSTEMI)
• ST segment elevation myocardial infarction (STEMI)

Aetiology

ACS is commonly caused by rupture of an atheromatous plaque in a coronary artery. This results in the accumulation of fibrin and platelets to repair the damage. This results in a thrombus formation leading to partial or complete occlusion of the coronary artery and distal myocardial cell death.

Epidemiology

Around 114?000 patients with ACSs are admitted to the hospital each year in the United Kingdom. Coronary heart disease (CHD) is the most common cause of death in the United Kingdom with around one in five men and one in seven women dying each year from CHD.

History

• Consider the history of chest pain or discomfort.
• Cardiovascular (CVS) risk factors.
• Family history of CHD.
• History of CHD, previous treatment and investigations:
• Pain or discomfort in the chest and/or the arms, back or jaw lasting longer than 15?minutes
• Chest pain with nausea and vomiting, sweating and/or breathlessness
• Abrupt deterioration in stable angina, with recurring chest pain discomfort occurring more frequently with little or no exertion and often lasting longer than 15?minutes.

Examination

• Clinical examination is often of little value in diagnosing ACS.
• It can identify alternative causes of chest pain (localised tenderness).
• Look for evidence of the aforementioned symptoms (sweating, SOB, shock).
• Full CVS, respiratory and abdominal assessment.
• Look for signs of heart failure.
• Examine chest wall for local tenderness and other possible causes of chest pain (costochondritis).

Investigations

• Vital signs - RR, HR, BP (both arms) and SpO2
• Cardiac monitoring - to identify underlying rhythm and arrhythmias
• 12-Lead ECG:
  • To confirm a cardiac basis for presentation and may show pre-existing structural or CHD.
  • ECG changes that occur during episodes of angina (ischaemia) T-wave inversion or ST segment depression.
  • Look for ST segment elevation suggestive of an STEMI.
• Bloods:
  • FBC, U&Es, LFTs, clotting screen and glucose
  • Troponin - should be taken immediately in suspected ACS, but negative result can only be used to rule ACS at 6 and 12?hours, respectively
• CXR - useful to show complications of ischaemia (e.g. pulmonary oedema) or to explore alternative diagnoses (e.g. pneumothorax, aortic aneurysm)

Management

• Refer to local protocols and care pathways.
• 999 Ambulance is required for transfer direct to cardiology in cases of STEMI for primary coronary intervention (PCI) or ED in other cases of ACS.
• IV access.
• IV morphine (dose titrated to pain with antiemetic).
• Oxygen (as required to meet target oxygen saturation of 94-98%).
• Nitrates (GTN if systolic BP?>?90?mmHg).
• Aspirin (stat dose of 300?mg).

TOP TIP:

• Chest pain relieved by GTN does not exclude ACS.
• A normal ECG does not exclude an ischaemic cause.

Anaphylaxis

Definition

Anaphylaxis is a severe, life-threatening and systemic hypersensitivity reaction to a foreign protein. Common examples include drugs, food products and insect stings. The resulting vasodilation and bronchospasm causes life-threatening symptoms.

Aetiology

True anaphylaxis does not occur on the first exposure to the allergen as the patient needs to have been exposed previously and therefore sensitised to the protein. Further repeated exposure leads to significant histamine release that increases on each subsequent exposure.

Epidemiology

The incidence of anaphylaxis is increasing in the United Kingdom and is suggested to be around 1-3 reactions per 10?000 population per annum. The overall prognosis of anaphylaxis is good. Mortality is increased within the asthmatic population, specifically those with poorly controlled asthma. Mortality rates from anaphylaxis in the United Kingdom are estimated at around 20 per annum.

History

• May be PMH of anaphylaxis or allergic response
• Sudden onset of symptoms (usually within minutes)
• Identifiable trigger (not always possible)

Examination

Patients with suspected anaphylaxis should be assessed using the ABCDE approach as follows:

Airway

• Hoarse voice
• Airway swelling
• Stridor

Breathing

• Shortness of breath
• Tachypnoea
• Tiredness/exhaustion
• Cyanosis
• Respiratory arrest

Circulation

• Signs of shock (pale and clammy)
• Tachycardia
• Hypotension
• Cardiac arrest

Skin/Mucosal

• Often first feature
• Erythema
• Urticaria
• Angioedema

Others

• Gastrointestinal disturbance (abdominal pain, vomiting and diarrhoea)

Investigations

• Investigation should not delay resuscitation.
• Vital sign monitoring should be established (RR, SpO2, HR and ECG monitoring).
• 12-Lead ECG.
• CXR.
• ABG.
• Bloods (including mast-cell tryptase to confirm anaphylaxis diagnosis).

Management

• Call for help.
• Lie flat and raise legs (some patients may benefit from sitting up if respiratory distress is the key feature, blood pressure is not compromised and the patient is not feeling dizzy or does not faint).
• Give intramuscular adrenaline.*
• High flow oxygen.
• IV access and fluid challenges of 500-1000?ml in adults and 20?ml/kg in children.*
• IV antihistamine.*
• IV steroids.*

*Please see the latest guidelines for specific drugs and doses.

Please refer to the latest guidelines from the Resuscitation Council (UK) available at www.resus.org.uk.

Reproduced with the kind permission from the Resuscitation Council (UK).

Aortic dissection (thoracic)

Definition

Aortic dissection is the tearing within the thoracic aorta allowing for blood to create a false lumen between the inner and the outer tunica media. There are different types classified by location. Type A involves the ascending aorta and is most common, whereas type B involves the descending aorta. Aortic dissection can lead to occlusion of the aorta and its branches (carotid, coronary, subclavian, spinal,...