Acute respiratory distress syndrome (ARDS) occurs when fluid builds up in the tiny, elastic air sacs (alveoli) in your lungs. The fluid keeps your lungs from filling with enough air, which means less oxygen reaches your bloodstream.

ARDS is divided into 3 categories of severity: mild, moderate, and severe based on oxygenation defects and clinical criteria

Level of severity


200 mm Hg < PaO2/FIO2 ≤ 300 mm Hg* with PEEP or CPAP ≥ 5 cm H2O


100 mm Hg < PaO2/FIO2 ≤ 200 mm Hg with PEEP ≥ 5 cm H2O


PaO2/FIO2 ≤ 100 mm Hg with PEEP ≥ 5 cm H2O

PATHOPHYSIOLOGY  -  In ARDS, pulmonary or systemic inflammation leads to release of cytokines and other proinflammatory molecules. The cytokines activate alveolar macrophages and recruit neutrophils to the lungs, which in turn release leukotrienes, oxidants, platelet-activating factor, and proteases. These substances damage capillary endothelium and alveolar epithelium, disrupting the barriers between capillaries and airspaces. Edema fluid, protein, and cellular debris flood the airspaces and interstitium, causing disruption of surfactant, airspace collapse, ventilation-perfusion mismatch, shunting, and pulmonary hypertension. The airspace collapse more commonly occurs in dependent lung zones. This early phase of ARDS is termed exudative. Later, there is proliferation of alveolar epithelium and fibrosis, constituting the fibro-proliferative phase.


  • Acid aspiration
  • Pneumonia
  • Diffuse alveolar hemorrhage
  • Drowning
  • Fat embolism
  • Lung transplantation
  • Pulmonary contusion
  • Irritant gas inhalation
  • Sepsis
  • Trauma with prolonged hypovolemic shock
  • Drug overdose (eg, aspirin, cocaine, opioids, phenothiazines, tricyclics)
  • Burns
  • Cardiopulmonary bypass
  • Massive blood transfusion (> 15 units)
  • Neurogenic pulmonary edema due to stroke, seizure, head trauma, anoxia
  • Pancreatitis
  • Preeclampsia
  • Septic abortion

SYMPTOMS - The signs and symptoms of ARDS can vary in intensity, depending on its cause and severity, as well as the presence of underlying heart or lung disease. They include:

  • Severe shortness of breath
  • Labored and unusually rapid breathing
  • Low blood pressure
  • Confusion and extreme tiredness
  • confusion or alteration of consciousness
  • cyanosis
  • tachypnea
  • tachycardia
  • and diaphoresis
  • Cardiac arrhythmia
  • and coma


Chest x-ray, Arterial blood gas (ABG) measurement, CT SCAN LUNGS


Ars Album - Great anguish and restlessness. Changes place continually. Fears, Unable to lie down; fears suffocation. Air-passages constricted. Asthma worse midnight. Burning in chest. Suffocative catarrh. Cough worse after midnight; worse lying on back. Expectoration scanty, frothy. Darting pain through upper third of right lung. Wheezing respiration. Hćmoptysis with pain between shoulders; burning heat all over. Cough dry, as from sulphur fumes; after drinking.

Aconite - Great fear, anxiety, and worry accompany every ailment, however trivial. Delirium is characterized by unhappiness worry, fear. Constant pressure in left chest; oppressed breathing on least motion. Hoarse, dry, croupy cough; loud, labored breathing. Child grasps at throat every time he coughs. Very sensitive to inspired air. Shortness of breath. Larynx sensitive. Stitches through chest. Cough, dry, short, hacking; worse at night and after midnight. Hot feeling in lungs. Blood comes up with hawking. Tingling in chest after cough.

Belladonna - Drying in nose, fauces, larynx, and trachea. Tickling, short, dry cough; worse at night. Larynx feels sore. Respiration oppressed, quick, unequal. Cheyne-Stokes respiration (Cocaine; Opium). Hoarse; loss of voice. Painless hoarseness. Cough with pain in left hip. Barking cough, whooping cough, with pain in stomach before attack, with expectoration of blood. Stitches in chest when coughing. Larynx very painful; feels as if a foreign body were in it, with cough.

Sambucus Nigra - Chest oppressed with pressure in stomach, and nausea Hoarseness with tenacious mucus in larynx. Paroxysmal, suffocative cough, coming on about midnight, with crying and dyspnśa. Spasmodic croup. Dry coryza. Sniffles of infants; nose dry and obstructed. Loose choking cough. When nursing child must let go of nipple, nose blocked up, cannot breathe. Child awakes suddenly, nearly suffocating, sits up, turns blue. Cannot expire (Meph)

Antimonium-Tart - Great rattling of mucus, but very little is expectorated. Velvety feeling in chest. Burning sensation in chest, which ascends to throat. Rapid, short, difficult breathing; seems as if he would suffocate; must sit up. Emphysema of the aged. Coughing and gaping consecutively. Bronchial tubes overloaded with mucus. Cough excited by eating, with pain in chest and larynx. Śdema and impending paralysis of lungs. Much palpitation, with uncomfortable hot feeling. Pulse rapid, weak, trembling. Dizziness, with cough. Dyspnśa relieved by eructation. Cough and dyspnśa better lying on right side--(opposite Badiaga)