Respiratory Functions & Pathology

• Heart Attack

  circulation problem where blood flow to the heart is blocked, typically by a blood clot

  = leads to heart muscle damage cos of blockage in coronary artery, lack of O2
• Cardiac Arrest

  an electrical malfunction in the heart's rhythm, often due to an abnormal heartbeat, leading to the heart stopping or beating ineffectively
• Heart Attack vs Cardiac Arrest

  heart attack = circulation problem, cardaic arrest = electrical

  heart attack symptoms = chest pain, SOB + sweating

  cardiac attack - loss of consciousness, no pulse + no breathing

  
• Coronary Heart Disease

  fatty material builds up in arteries - atherosclerosis of coronary arteries

  causes arteries to narrow = reduced blood flow

  if a piece of atheroma breaks off, can cause a clot - cause MI
• Risk Factors of Coronary Heart Disease

  high cholesterol, diabetes

  smoking, overweight, low exercise levels, fatty diet

  family history, age + ethnic background
• Symptoms of Coronary Heart Disease

  chest pain, SOB, feeling faint or nausea
• Myocardial Infarction

  sudden loss of blood flow to a part of the heart muscle

  if left, heart muscle starts to die due to lack of oxygen

  usually caused by CHD but also drug misuse, stress ....
• Pericaditis

  inflammation of pericardium

  usually caused by viral infection

  painful to breathe
• Myocarditis

  inflammation of myocardium

  often caused by viral infection

  can weaken the heart muscle
• Endocarditis

  inflammation of endocardium

  usually caused by bacterial systemic infection

  causes valve to leak + deterioate
• Cardiomyopathies

  heterogenous groups of diseases of the heart muscle that can lead to heart failure

  
• Hypertrophic Cardiomyopathy

  abnormal thickening of the heart muscle, most commonly affecting the interventricular septum

  = can obstruct blood flow out of the heart

  caused by autosomal genetic mutations in sarcomere protein genes

  can create arrhythmias, heart failure, sudden cardiac death
• Dilated Cardiomyopathy

  heart chambers, esp the left ventricle, become enlarged + weakened

  = reduces the heart's ability to pump blood effectively

  caused by genetic mutations/alcohol abuse/viral infections/chemotherapy drugs

  clinical features - fatigue, SOB, peripheral oedema, arrhythmias

  complications - heart failure + thromboembolism
• Restrictive Cardiomyopathy

  heart muscle becomes rigid + less elastic, leading to impaired ventricular filling

  = normal contraction but poor relaxation -- diastolic dysfunction

  clinical features - symptoms of right heart failure, fatigue, peripheral oedema

  complications - arrhythmias, thromboembolism
• Arrhytmias

  disturbances in the heart's rhythm caused by abnormalities in the generation/conduction of electrical impulses

  broadly categorised on rate (tachycardia vs bradycardia) + origin (supraventricular vs ventricular)
• Supraventricular Arrhythmias

  originates above the ventricles - in the atria or AV node
• Supraventricular Arrhythmias - Sinus Tachycardia

  rate - >100 bpm

  cause - physiologic (exercise, fever, anxiety) or pathologic (loss of fluid, hyperthyroidism)

  ECG - norm P waves, regular rhythm
• Supraventricular Arrhythmias - Sinus Bradycardia

  rate - <60 bpm

  causes - athletes, hypthyroidism, beta-blockers, digoxin

  ECG - norm P waves, slow regular rhythm
• Supraventricular Arrhythmias - Atrial Fibrilation

  irregular rhythm, no discernible P waves

  cause - hypertension, heart failure, aclohol, hyperthyroidism

  complications - stroke + heart failure

  ECG - irregularly spaced QRS, fibrillatory baseline
• Ventricular Arrhythmias - Ventricular Tachycardia

  rate - >100 bm, wide QRS complexes

  causes - ischaemia, cardiomyopathy, drug toxicity, electrolyte disturbances

  emergency - can degenerate into ventricular fibrilation
• Ventricular Arrythmias - Ventricular Fibrilation

  chaotic, disorganised ventricular activity -- no cardiac output

  ECG - irregular, coarse/fine undulating baseline

  outcome - fatal w out immediate defibrillation
• Chronic Obstructive Pulmonary Disease (COPD)

  chronic airway obstruction umbrella term

  a progressive, irreversible lung disease characterised by chronic airflow limitation that is not fully reversible

  
• COPD - Definition

  a chronic inflammatory lung disease that causes obstruction of airflow from the lungs

  primarily due to long-term exposure to noxious particles/gases, most commonly cigarette smoke
• COPD - Chronic Bronchitis

  cough + sputum production for at least 3 months in 2 consecutive yrs

  increase in mucus gland tissue + goblet cells

  excessive mucus production + airway narrowing

  inflammation leads to obstruction
• COPD - Emphysema

  perm enlargement of airspaces distal to the terminal bronchioles w destruction of alveolar walls

  = loss of elastic recoil, air trapping + hyperinflation
• Asthma-COPD Overlap

  age = >40 w history of asthma

  persistent airflow limitation w partially reversible components

  higher symptom burden than COPD or astma alone

  increased freq + severity of exacerbations
• Bronchiectasis

  long-term condition where airways become widened

  excess mucus build up

  freq infections

  SOB + persistent cough

  various causes but often due to severe previous lung conditions e.g. TB

  
• Pneumonia

  inflammation of the alveoli

  alveoli fill w fluid + pus

  caused by bacteria, virus or fungi

  can affect both healthy + unhealthy ppl

  community/hospital acquired
• Asthma

  recurrent inflammation of airways leads to narrowing

  severe asthma debilitating

  airways increasingly damaged over time

  SOB, expiratory wheeze, chest pain

  worse at night/cold

  managed w anti-inflammatory drugs + bronchodilators
• Cystic Fibrosis

  inherited condition

  lungs + digestive system become clogged w thick, sticky phlegm

  starting in childhood, daily physio vital for airway clearance managment + for physical activitoy

  manual techniques + postural drainage = key

  recurrent chest infections = complication
• Respiratory Failure

  respiraory complication

  not enough O2/ too much CO2

  type 1 - low O2 (hypoxia) = often caused by resp/cardiac conditions

  type 2 - low O2 (hypoxia) + high CO2 (hypercapnia) = often caused by neuro conditions or fatigue which has caused someone to start w type 1 then tip into type 2 over time
• Neuro Conditions w Respiratory Complications

  MS

  Stroke

  MND (Motor Neuron Disease)

  Spinal injuries

  Brain tumour
• Direct Surgical Complications to Respiratory System

  post-op abdominal surgery

  thoracic surgery - damage to muscles + nerves

  cardiac surgery - damage to phrenic nerve
• Indirect Surgical Complications to Respiratory System

  obseity + post-surgery

  anaesthesia lowers contraction of resp muscles

  sedatives affect neural structures of resp muscles
• Atmospheric Oxygen

  oxygen = highly reactive + odourless gas

  makes up 21% of atmospheric air + vital for life
• Hypoxaemia

  reduced PaO2 (partial pressure of oxygen) in arterial blood

  norm PaO2 = 80-100 mmHg on room at sea level

  hypoxaemia = <80mmHg, severe = <40 mmhg, moderate = 40-60, mild = 60-80
• Causes of Hypoxaemia - Hypoventilation

  a decrease in alveolar ventilation leads to decrease in PaO2 + increase in PaCO2

  caused by CNS depression (e.g. drugs), neuromuscular diseases + chest wall disorders
• Causes of Hypoxaemia - Diffusion Impairment

  impaired oxygen transfer across alveolar-capillary membrane

  causes = pulmonary fibrosis, interstitial lung disease, emphysema
• Signs & Symptoms of Hypoxaemia

  SOB + rapid breathing

  cyanosis

  headache, confusion + fatigue
• Management of Hypoxaemia

  correcting the oxygen level via oxygen therapy + treating the underlying cause