Beyond the EU: DORA and NIS 2 Directive's Global Impact
11-AW-0041 SA_Pulmonary Aspiration.pdf
1. Rawlinson, E. Pulmonary aspiration. Anesthesia and Intensive Care Medicine. 2007:8(9);365-367.
Pulmonary Aspiration
2. Introduction
• Defined as the inhalation of material into the airway below the
level of the true vocal cords (subglottic space)
• Occurs as a consequence of the passive regurgitation or active
vomiting of gastric contents in patients lacking sufficient
protective laryngeal reflexes
• Pulmonary aspiration remains one of the most feared
complications of anesthesia to this day, and its prevention is a
critical part of anesthetic practice
3. • Overall aspiration incidence in adults
is approximately 1 in 3000 patients:
– In those undergoing emergency
surgery this risesto 1 in 600-800
patients
– Caesarean section under general
anesthesia1 in 400-900 patients
• Of those patients who aspirate and
develop symptoms, mortality is
8% to 10%
• Aspiration occurs most frequently
during laryngoscopy and at extubation,
but can occur at any point in the
perioperative period
Incidence and Risk Factors
4. • There are many factors that may
predispose patients to a greater
risk of aspiration
– However, 50% of patients
will have no preoperatively
identifiable risk factor
• Although used and taught as a
means of preventing pulmonary
aspiration, cricoid pressure at
induction of anesthesia before
intubation does not guarantee that
aspiration will not occur
Incidence and Risk Factors
5. • Consequences of aspiration are
influenced by:
– The nature of the aspiration (fluid
or particulate)
– pH of aspirate
– Volume of aspirate
– The host response
• There is no critical amount of
substance that is completely safe to
aspirate
– Buffering gastric contents in an
attempt to reduce the severity of
pulmonary disease may not be
productive
Headline Initial Caps
6. • Aspiration may lead to a variety of
symptoms and diseases
• Three of the most clinically
important complications are:
– Aspiration pneumonitis
– Aspiration of particulate matter
– Aspiration pneumonia
Clinical Presentation
7. • A non-infective physiochemical
process caused by the
inhalation of sterile acid
• Consists of two phases:
– Initial phase
– Second phase
Aspiration Pneumonitis (Mendelson’s Syndrome)
8. • Involves a chemical burn to the airways,
occurs within 5 seconds of exposure
• Six hours later there is loss of ciliated
and non-ciliated cells, particularly
alveolar type II cells
• This leads to an increase in alveolar
permeability
Alveolar Capillary Junction
Aspiration Pneumontis – Initial Phase
10. Acute lung injury ARDS Multi-organ failure
Release of
pro-inflammatory cells
What may ensue following the
release of pro-inflammatory cells is:
Aspiration Pneumontis – Second Phase5
11. • May cause airway obstruction of either
large or small airways
• Complete obstruction causes
immediate arterial hypoxemia and may
be rapidly fatal
• Partial obstruction leads to atelectasis
distal to the obstruction
Aspiration of Particulate Matter
12. • Infective process caused by the
inhalation of gastric contents or
bacterial super infection of the
lung damaged by acid aspiration
– A patient who has aspirated
gastric content is at a greater
risk of developing pneumonia
Aspiration Pneumonia
13. • Aspiration may be diagnosed
from direct visualization of gastric
contents on the vocal cords and in
the trachea during laryngoscopy
• Or, it may not be directly observed
and can occur silently at any point
in the perioperative period
• Aspiration should be considered as
part of the differential diagnosis of
a number of clinical emergencies
presenting under anesthesia
Clinical Features of Aspiration
16. Aspiration Risk Factors, Patients
• Surgical procedure
• Laparoscopic techniques
• Position
Operation factors
• Insufficient depth of anesthesia
• Gas Insuffiation from mask
ventilation of LMA ventilation
• Early removal of ETT
Anesthetic factors
