Critical Care Nursing Theory
Aspiration
Aspiration
- Aspiration of stomach contents into the lungs is a serious complication that
may cause pneumonia
- It can occur when the protective airway reflexes are decreased or absent
from a variety of factors
Clinical Manifestations
1- Tachycardia,
2- Dyspnea,
3- Central cyanosis,
4- Hypertension,
5- Hypotension,
6- Death
Nursing Alert
- When a nonfunctioning nasogastric tube allows the gastric contents to
accumulate in the stomach, a condition known as silent aspiration may
result.
- Silent aspiration often occurs unobserved and may be more common than
suspected.
- If untreated , massive inhalation of gastric contents develops in a period of
several hours.
Pathophysiology
- The primary factors responsible for death and complications after
aspiration of gastric contents are :a- The volume of the aspirated gastric contents.
b-The character of the aspirated gastric contents
Dr. Abdul-Monim Batiha-
Assistant Professor Of Critical Care Nursing
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Critical Care Nursing Theory
Aspiration
A-The volume of the aspirated gastric contents.
- A small, localized aspiration from regurgitation can cause:a - Pneumonia
b - Acute respiratory distress;
- A massive aspiration is usually fatal
B-The character of the aspirated gastric contents.
- A full stomach contains solid particles of food. If these are aspirated, the
problem then becomes one of :a- Mechanical blockage of the airways
b- Secondary infection.
- During periods of fasting, the stomach contains acidic gastric juice, which,
if aspirated, may be very destructive to the alveoli and capillaries.
- Fecal contamination (more likely seen in intestinal obstruction) increases
the likelihood of death because :a - The endotoxins produced by intestinal organism may be absorbed
systemically,
b- The thick proteinaceous material found in the intestinal contents
may obstruct the airway, leading to atelectasis and secondary
bacterial invasion.
Aspiration pneumonitis
- It may develop from aspiration of substances with a pH of less than 2.5 and
a volume of gastric aspirate greater than 0.3 mL per kilogram of body
weight (20 to 25 mL in adults).
- Aspiration of gastric contents causes a chemical burn of the
tracheobronchial tree and pulmonary parenchyma . An inflammatory
response occurs. This results in the destruction of alveolar–capillary
endotheliam cells, with a consequent outpouring of protein-rich fluids into
the interstitial and intra-alveolar spaces. As a result, surfactant is lost,
Dr. Abdul-Monim Batiha-
Assistant Professor Of Critical Care Nursing
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Critical Care Nursing Theory
Aspiration
which in turn causes the airways to close and the alveoli to collapse.
Finally, the impaired exchange of oxygen and carbon dioxide causes
respiratory failure.
- Aspiration pneumonia develops following inhalation of colonized
oropharyngeal material.
- The pathologic process involves an acute inflammatory response to
bacteria and bacterial products.
- Most commonly, the bacteriologic findings include gram-positive cocci,
gram-negative rods, and occasionally anaerobic bacteria
Risk Factors for Aspiration
1- Seizure activity
2- Decreased level of consciousness from trauma, drug or alcohol
3- Intoxication, excessive sedation, or general anesthesia
4- Nausea and vomiting in the patient with a decreased level of
consciousness
5- Stroke
6- Swallowing disorders
7- Cardiac arrest
8- Silent aspiration
Nursing Alert
- When a nonfunctioning nasogastric tube allows the gastric contents to
accumulate in the stomach, a condition known as silent aspiration may
result.
- Silent aspiration often occurs unobserved and may be more common than
suspected.
- If untreated, massive inhalation of gastric contents develops in a period of
several hours.
Dr. Abdul-Monim Batiha-
Assistant Professor Of Critical Care Nursing
3
Critical Care Nursing Theory
Aspiration
Prevention
- Prevention is the primary goal when caring for patients at risk for
aspiration.
Managment:A- Compensating For Absent Reflexes
- Aspiration is likely to occur if the patient cannot adequately coordinate
protective glottic, laryngeal, and cough reflexes.
- This hazard is increased if the patient has a distended abdomen, is in a
supine position, has the upper extremities immobilized by intravenous
infusions or hand restraints, receives local anesthetics to the oropharyngeal
or laryngeal area for diagnostic procedures, has been sedated, or has had
long-term intubation.
- When vomiting, a person can normally protect the airway
- When vomiting, a person can normally protect the airway by sitting up or
turning on the side and coordinating breathing, coughing, gag, and glotti
reflexes.
- If these reflexes are active, an oral airway should not be inserted.
- If an airway is in place, it should be pulled out the moment the patient gags
so as not to stimulate the pharyngeal gag reflex and promote vomiting and
aspiration.
- Suctioning of oral secretions with a catheter should be performed with
minimal pharyngeal stimulation.
Dr. Abdul-Monim Batiha-
Assistant Professor Of Critical Care Nursing
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Critical Care Nursing Theory
Aspiration
B- Assessing Feeding Tube Placement
- Even when the patient is intubated, aspiration may occur even with a
nasogastric tube in place.
- This aspiration may result in nosocomial pneumonia.
- Assessment of tube placement is key to prevent aspiration. The best
method for determining tube placement is via an x-ray.
- There are other non-radiologic methods that have been studied.
- Observation of the aspirate and testing of its pH are the most reliable.
Gastric fluid may be grassy green, brown, clear, or colorless.
- An aspirate from the lungs may be offwhite or tan mucus. Pleural fluid is
watery and usually strawcolored .Gastric pH values are typically lower or
more acidic that that of the intestinal or respiratory tract.
- Gastric pH is usually between 1 and 5, while intestinal or respiratory pH is
7 or higher .
- There are differences in assessing tube placement with continuous versus
intermittent feedings.
- For intermittent feedings with small-bore tubes, observation of aspirated
contents and pH evaluation should be performed. For continuous feedings,
the pH method is not clinically useful due to the infused formula.
- The patient who is receiving continuous or timed-interval tube feedings
must be positioned properly.
- The patient receiving a continuous infusion is given small volumes under
low pressure in an upright position, which helps to prevent aspiration.
- Patients receiving tube feedings at timed intervals are maintained in an
upright position during the feeding and for a minimum of 30 minutes
afterward to allow the stomach to empty partially.
- Tube feedings must be given only when it is certain that the feeding tube is
Dr. Abdul-Monim Batiha-
Assistant Professor Of Critical Care Nursing
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Critical Care Nursing Theory
Aspiration
positioned correctly in the stomach.
- Many patients today receive enteral feeding directly into the duodenum
through a small-bore flexible feeding tube or surgically implanted tube.
- Feedings are given slowly and regulated by a feeding pump.
- Correct placement is confirmed by chest x- ray.
C- Identifying Delayed Stomach Emptying
- A full stomach may cause aspiration because of :a- Increased intragastric pressure.
b- Increased extragastric pressure.
- The following clinical situations cause a delayed emptying time of the
stomach and may contribute to aspiration:
1- Intestinal obstruction;
2- Increased gastric secretions in gastroesophageal reflex disease;
3- Increased gastric secretions during anxiety, stress, or pain;
4- Abdominal distention because of ileus, ascites, peritonitis,
5- Use of opioids and sedatives,
6- Severe illness,
7- Vaginal delivery.
- When a feeding tube is present, contents are aspirated, usually every 4
hours, to determine the amount of the last feeding left in the stomach
(residual volume).
- If more than 50 mL is aspirated, there may be a problem with delayed
emptying, and the next feeding should be delayed or the continuous feeding
stopped for a period of time.
D- Managing Effects of Prolonged Intubation
- Prolonged endotracheal intubation or tracheostomy can depress the
laryngeal and glottic reflexes because of disuse.
Dr. Abdul-Monim Batiha-
Assistant Professor Of Critical Care Nursing
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Critical Care Nursing Theory
Aspiration
- Patients with prolonged tracheostomies are encouraged to phonate and
exercise their laryngeal muscles.
- For patients who have had long-term intubation or tracheostomies, it may
be helpful to have a rehabilitation therapist experienced in speech and
swallowing disorders work with the patient to assess the swallowing reflex.
Dr. Abdul-Monim Batiha-
Assistant Professor Of Critical Care Nursing
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