Pulmonary Oedema

In this podcast we look at pulmonary oedema - a very important condition to be able to diagnose and effectively treat.

Lecture by

Video Duration: 8 minutes

  • Pulmonary Oedema
    Created by Mehul Patel
    General
    Epidemiology

    Pulmonary oedema is the abnormal accumulation of fluid in the interstitial or alveolar spaces of the lungs. There is a change in hydrostatic or oncotic pressure across the alveolar membrane such that fluid moves across from the capillaries into the alveolar space.

    Pathology

    There are two types: Cardiogenic and non-cardiogenic

    Cardiogenic (hydrostatic)- caused by elevated pulmonary capillary pressure from left sided heart failure, can also occur due to renal injury, iatrogenic fluid overload

    Non-cardiogenic can be due to either:

    1) Loss of protein: Liver disease, nephrotic syndrome, protein losing enteropathy

    2) Altered pulmonary capillary membrane permeability. e.g- acute respiratory distress syndrome, lymphatic insufficiency, lymphatic obstruction

    Top three causes

    The following occur in addition to a background of heart disease and act as an additional insult.

    • Fluid Overload- may be iatrogenic or secondary to renal impairment.
    • Cardiac event- MI, arrhythmia,
    • Infection
    Clinical Features
    Symptoms
    • Shortness of breath
    • Rapid shallow breathing
    • A cough with pink, frothy sputum
    • Orthopnoea
    • Paroxysmal nocturnal dyspnoea


    Signs


    • Patient appears in respiratory distress, tachypnea and tachcardic
    • Cyanosis
    • O2 Saturation < 90% on room air
    • Rapid, low pulse
    • There may be extended neck veins and a raised JVP
    • Breathing may be laboured and wheezing or rapid and panting. There may be a fine rattling sound audible (bibasal crepitations)
    • Gallop rhythm (3rd and 4th heart sound)


    Investigations
    Cultures

    Blood- to check for sepsis

    Bloods

    Arterial: ABG and check pH (for respiratory acidosis)

    Venous:

    BNP- (elevated in cases of LV dysfunction)

    Renal function test (dysfunction can lead to volume overload)

    U+E (electrolyte imbalance caused by acidosis)

    Glucose: to look for hyperglycemia (diabetic cardiomyopathy)

    Cardiac enzymes (MI)

    Liver function test (impairment can reduces serum protein)

    Imaging

    Chest X-ray- exclude other causes of dyspnoea and confirm pulmonary oedema

    Scopic/Biopsy

    None

    Functional

    ECG- find any signs of arrhythmias or acute coronary events.

    Transthoracic Echocardiogram- to look at heart function

    Treatment
    Conservative

    None

    Medical

    In the case of Cardiogenic pulmonary oedema: Resuscitate with respect to ABC

    Give high flow O2 by facemask and monitor O2 saturation

    Gain IV access

    Loop diuretic: Furosemide IV 20-40mg - change to oral when patient improves

    If patient is in pain or distress: diamorphine 2.5-5mg IV or Morphine 5-10mg IV

    Anti-emetic: Metoclopramide 10mg IV (*****Do Not give cyclizine as it reduces LV function)

    Vasodilators: GTN (Systolic blood pressure >110mmHG)

    Thrombo-embolism prophylaxis: low molecular weight heparin

    Surgical

    None