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Aspiration is defined as inhaling a foreign body or fluid into the lower respiratory tract. This is most often gastric contents or a foreign body. In obstetrics, the aspiration of amniotic fluid or meconium by the newborn.

Swallowing - Topography of the upper respiratory and swallowing tracts

Predisposition[edit | edit source]

  • Disorders of consciousness (coma,intoxication);
  • general anesthesia (especially introduction and withdrawal from anesthesia ) and sedation;
  • alcoholism;
  • tracheostomy;
  • endotracheal intubation
  • hiatal hernias, esophageal diseases, decreased lower esophageal sphincter tonus (Benzodiazepines, Opiates, Hypnotics, Vagolytics);
  • upper airway stenosis.

Patophysiology[edit | edit source]

  • The consequences of aspiration and the resulting clinical pictures can be divided into three groups:
    • aspiration of acidic gastric contents;
    • solid body aspiration;
    • aspiration of bacterial contaminated material.
Aspiration pneumonia in a patient with neurological degenerative disease, parenchymal necrosis and aspirate particles are seen. Stained with hematoxylin-eosin.

Aspiration of an inert body or particle[edit | edit source]

  • Solids, blood clots, food residues;
  • occurs immediate airway obstruction (partial or complete), atelectasis and reflective bronchospasm.

Symptoms[edit | edit source]

Auscultation[edit | edit source]

  • Lateral differences (weakened breathing), in- or expiratory wheezing (if spasm persists even after airway lavage → suspicion of more foreign bodies).

X-ray image[edit | edit source]

  • Finding a foreign body if it is large enough with X-ray contrast;
  • emphysematous changes (valve mechanism) or atelectasis.

Blood gas analysis[edit | edit source]

  • Decrease in paO2 and increase in paCO2

Therapy[edit | edit source]

  • O2;
  • upside-down positioning, foreign body digital removal attempt, direct laryngoscopy, rigid bronchoscopy, Heimlich maneuver;
  • endotracheal suction and endobronchial lavage, in the case of small particles we can aspirate using fibrobronchoscopy, larger bodies bronchoscopy with a rigid bronchoscope;
  • thoracotomy.

Acidic stomach contents[edit | edit source]

Synonyms[edit | edit source]

  • Mendelson's syndrome

Symptoms[edit | edit source]

  • dyspnoea, tachypnoea, cough;
  • anxiety, fear;
  • laryngospasm, bronchospasm, cyanosis, foamy sputum;
  • tachycardia, pressure drop, shock.

Complications[edit | edit source]

  • ARDS (approximately 22% of patients);
  • secondary infections;
  • SIRS, MOF.

Pathophysiology, process[edit | edit source]

  • Chemical-toxic phase
    • in 5 seconds the aspirate enters the central airways;
    • in 15 seconds it is neutralized in the lungs;
    • airway epithelial necrosis - desquamation of the superficial epithelial layer, complete loss of epithelialization in 6 hours, regeneration in 3 days, complete regeneration in 7 days;
    • second type pneumocytes degenerate within 4 hours after aspiration → increased pulmonary permeability and pulmonary edema.
  • Inflationary phase
    • acidity-induced proinflammatory changes - cytokines , TNFα, IL-8 → inflammatory reaction → increased permeability → pulmonary edema.

Auscultation[edit | edit source]

  • rhonchi, whistles, squeaks.

X-ray image[edit | edit source]

  • diffuse infiltration of affected areas, atelectasis;
  • we scan immediately after aspiration and then 4 hours later (even in an asymptomatic patient) - the first changes recognizable on an X-ray may occur 4-8 hours after aspiration.

Pulmonary function, blood gas analysis[edit | edit source]

  • decrease in paO2 and increase or also decrease in paCO2, decrease in lung compliance , increase in lung resistance, initially respiratory alkalosis later turns into metabolic acidosis, increase in respiratory work;
  • decrease in blood pressure, increase in pulmonary arterial pressure.

Therapy[edit | edit source]

  • oropharyngeal suction, endotracheal suction (aspirate analysis - volume, pH, chemical analysis, microbiological examination), upside down position, we do not attempt edobronchial lavage or neutralization;
  • O2 supply (mask, CPAP), endotracheal intubation and artificial lung ventilation with PEEP, humidified air and inhalation therapy, patient positioning;
  • fibrobronchoscopy (within one hour of aspiration) - confirmation of the diagnosis, estimation of damage, suction of solids, atelectasis;
  • circulatory stabilization - volume therapy, careful catecholamine therapy;
  • lungs - use of bronchodilators (β2 sympathomimetics, theophylline);
  • physiotherapy (breathing training);
  • ATB - Cephalosporins of the 2nd generation + Metronidazole , alternative: aminopenicillins + lactamase β inhibitor
  • Ambroxol in high doses (surfactant and mucus production), surfactant application (locally bronchoscopically, systemically).

Bacteria-contaminated material[edit | edit source]

Symptoms[edit | edit source]

  • dyspnoea, tachypnoea;
  • bronchospasm;
  • later symptoms of pneumonia : fever, productive cough.

Auscultation[edit | edit source]

  • rhonchi, whistles.

X-ray image[edit | edit source]

  • infiltrates in the affected areas of the lungs.

Pulmonary function, blood gas analysis[edit | edit source]

  • decrease in paO2 and increase or also decrease in paCO2, decrease in lung compliance, increase in lung resistance, metabolic acidosis;
  • purulent, smelly tracheal secretion;
  • decrease in blood pressure, increase in pulmonary arterial pressure.

Therapy[edit | edit source]

Incidence of aspiration in anesthesia and intensive care[edit | edit source]

  • On average 1.4-6.5 : 10000.
  • The lowest risk of aspiration is in planned procedures in children older than one year and patients of groups ASA I and II (ASA = American Society of Anesthesiology).
  • In infants, patients in groups ASA IV and V, patients undergoing caesarean section and emergency procedures, the risk is ten times higher.
  • The highest risk of aspiration is in urgent intubations 375 : 10000.[1]
  • Only about one third of all cases are aspiration symptomatic - requires artificial lung ventilation > 24 hours.[2]
  • The greatest risk of aspiration is at the beginning of anesthesia, about 56% of aspirations are at the beginning of anesthesia, during anesthesia about 20% and when exiting anesthesia the incidence also reaches about 20%.

Prevention[edit | edit source]

Non-pharmacological[edit | edit source]

  • we perform for all patients undergoing the planned operation;
  • includes preoperative fasting:
    • do not eat any solid food for at least 6 hours before the operation;
    • no consumption of pure fluids (water) for at least two hours preoperatively;
    • in infants, the last breast-feeding within four hours before surgery;
      • if the patient is not fasting, we only perform life-saving surgery using the "crush intubation" technique.[1]

Pharmacological[edit | edit source]

  • use if known risk factors - smoking, gastroesophageal reflux, lower esophageal sphincter disorders, caffeine, body mass index over 30, pregnancy, trauma, shock;
    • increasing the pH of the stomach contents;
      • approximately 10–20 minutes before the operation, we give a solution of sodium citrate (in pregnant women undergoing a caesarean section);
      • histamine H2 blockers 2 in the evening and in the morning 2-3 hours before surgery - ranitidine, cimetidine;
      • proton pump inhibitors omeprazole, pantoprazole;
    • accelerating the emptying of gastric contents;

Links[edit | edit source]

Related articles[edit | edit source]

External links[edit | edit source]

References[edit | edit source]

  1. a b KRETZ, Franz-Josef a Frank TEUFEL. Anästhesie und Intensivmedizin. 1. vydání. Heidelberg : Springer, 2006. 695 s. s. 480. ISBN 3-540-62739-1
  2. HECK, Michael a Michael FRESENIUS. Repetitorium Anästhesiologie. 5. vydání. Heidelberg : Springer, 2007. 642 s. s. 441. ISBN 978-3-540-46575-1
  • DOEFFINGER, Joachim and Franz JESCH, et al. Intensive medical notebook. 4th edition. Wiesbaden: Abbott GMBH, 2002.  ISBN 3-926035-35-8 .
  • KRETZ, Franz-Josef and Frank TEUFEL. Anesthesia and intensive care. 1st edition. Heidelberg: Springer, 2006. 695 pp.  ISBN 3-540-62739-1 .
  • HECK, Michael and Michael FRESENIUS. Repetitorium Anästhesiologie. 5th edition. Heidelberg: Springer, 2007. 642 pp.  ISBN 978-3-540-46575-1 .