Gastroparesis in the heart-lung recipient can cause the
undesirable symptoms and several respiratory distress
due to aspiration pneumonia (
4). The mechanism of
posttransplant gastroparesis is thought to be multifactorial
(
5).
Gastroparesis might predispose to microaspiration and
pulmonary infections (
4), which was main cause in our
case. Frequent nausea, vomiting, and gastroesophageal
ref lux can lead to aspiration pneumonitis. Laryngeal
exposure to acid and aspiration of gastric contents may lead
to severe respiratory disorders. The mechanism involved
in the complication of bacterial pneumonia in patients
with aspiration of gastric contents, however, remains
uncertain. The effect of this aspiration is generally thought
to be caused by gastric acid because the gastric contents
introduced into the lungs can cause severe pulmonary
injury, which is indistinguishable from that caused by the
aspiration of an equivalent amount of gastric acid (
6).
Bacterial pneumonia is the result of infection of the
lower respiratory tract by microorganisms of the oral
and pharyngeal regions. Pseudomonas aeruginosa is an
opportunistic pathogen which colonizes at oropharynx
and is one of the potential pathogens isolated from sputum
samples from patients with respiratory aspiration of gastric
contents (
7). Bacterial adherence to the airway epithelium
is the first step of bronchopulmonary infections. Acid aspiration can worsen bacterial infection by a mechanism
involving bacterial cell adherence to the airway epithelium.
Ramphal et al. Ramphal et al previously repor ted
Pseudomonas aeruginosa can adhere efficiently to acidinjured
tracheal epithelium, but not to uninjured epithelium
(
8). The authors suggested that acid injury could expose
binding sites or change the surface structure of the cell
membrane, thus permitting adherence of a nonmucoid
strain of Pseudomonas aeruginosa by pili and subsequently
leading to bacterial pneumonia (
9). In our case, respiratory
aspiration of gastric contents induced airway epithelial
injury and enhanced Pseudomonas aeruginosa adherence
to the acid-injured epithelium, which led to the subsequent
development of bacterial pneumonia. Further, this case was
further complicated by the essential immunosuppressive
therapy.
Gastrointestinal complications may be an important
factor of respiratory infections or mortality during the
peri-operative period (
10) and the consequences of such
complication are well described in the literatures but the
microbiological consequences have rarely been evaluated.
The main finding in this case is Pseudomonas aeruginosa
pulmonary infection in the heart-lung transplant recipient
with the complication of gastroparesis. However, no further
attempts were made to obtain an etiologic diagnosis.
The diagnosis of Pseudomonas aeruginosa pneumonia
was not clearly proven. Nevertheless, colonization with
Pseudomonas aeruginosa was considered clinically
significant and antibiotic therapy was initiated by the
clinician (
11).
Heart-lung recipients with gastroparesis are at increased
risk for aspiration pneumonitis. In order to avoid the
morbidity of gastroparesis in this subset of fragile
patients, it may be prudent to perform a prophylactic
management, including surgery. Alternatively, a high
suspicion of gastroparesis should be maintained early in
the postoperative course.