- Pulmonary aspiration
medicine, aspiration is the entry of secretions or foreign material into the trachea and lungs. [cite web
title=Pulmonary aspiration (Treatment Guide)
The patient may either inhale the material, or it may be blown into the lungs during
positive pressure ventilationor CPR. As the right main bronchusis more vertical and of slightly wider lumen than the left, aspirated material is more likely to end up in this branch or one of its subsequent bifurcations.
As a rule of thumb, any condition which compromises a patient's level of consciousness and/or
gag reflexis a risk factor for pulmonary aspiration.
Causes of unconsciousness where aspiration may occur include
trauma(especially head injuries), poisoning(including drug/alcohol overdose), general anaesthetics, and diseases or metabolicconditions. Gastroesophageal reflux, a full stomach, pregnancy, and obesityall increase the risk of aspiration in the semiconscious.
fastingfor six hours before elective surgery is enough to empty the stomach. Severe injuries can slow the movement of digestafrom the stomach and through the duodenum.
alcohol poisoningis a relatively common cause of severe pulmonary aspiration as the alcohol renders the victim unconscious and can induce vomiting. Patients with neurological conditions may also aspirate food or drink.
During labour (
childbirth), early respiratory movements by the baby facilitate filling of alveolar ducts and alveolar lumens with elements of amniotic fluid: amniotic cells, squamousand squamous cells from fetal skin, lanugo, meconium. Reduced inflammatoryinfiltrate ( neutrophils) and capillarycongestion is present. Photos at: [http://www.pathologyatlas.ro/Aspiration%20Bronchopneumonia1.html 1]
If enough material enters the lungs, the patient may simply drown. However, small volumes of gastric acid contents can fatally damage the delicate lung tissue. Even small volumes of aspirated food may lead to
bronchopneumoniainfection. Chronic aspiration may lead to bronchiectasisand may cause some cases of asthma.
The lungs are normally protected against aspiration by a series of "protective reflexes" such as
coughingand swallowing. Significant aspiration can only occur if the protective reflexes are absent (in neurological disease, coma, drug overdose, sedationor general anesthesia). In intensive care, sitting patients up reduces the risk of pulmonary aspiration and ventilatorassociated pneumonia.
Measures to prevent aspiration depend on the situation and the patient. In patients at imminent risk of aspiration, endotracheal
intubationby a trained health professionalprovides the best protection. A simpler intervention that can be implemented is to lay the patient on their side in the "rescue position" (as taught in first aidand CPRclasses), so that any vomitusproduced by the patient will drain out their mouth instead of back down their pharynx. Some anaesthatists will use sodium citrate (to neutralise the stomach's high pH) and Metoclopramide (a pro-kinetic, to empty the stomach).
People with chronic
neurological disorders, for example, after a stroke, are less likely to aspirate thickened fluids.
The location of
abscesses caused by aspiration depends on the position one is in. If one is sitting or standing up, the aspirate ends up in the posterior basal segment of the right lower lobe. If one is on one's back, it goes to the superior segment of the right lower lobe. If one is lying on the right side, it goes to the superior segment of the right middle lobe, or the posterior basal segment of the right upper lobe. If one is lying on the left, it goes to the lingula.
Salt water aspiration syndrome
* [http://www.pathologyatlas.ro/Aspiration%20Bronchopneumonia1.html Atlas of Pathology]
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