Although we aim to preserve pleural integrity
during cardiac surgery in our institution, some surgeons
perform routine pleurotomy prior to IMA harvesting
to expose and prevent tension. This approach led us
to constitute this study. Altered respiratory system
functions are frequently observed after cardiac surgery.
Reduced FVC and arterial oxygen tension are found
to be responsible for the changes in the lung functions
and are related to increased morbidity and mortality
in the early postoperative period.[
1,
18] The effect of
pleurotomy on pulmonary function can be explained by
a higher incidence of pleural effusion and atelectasis,
increased intrapulmonary shunting, and postoperative
pleuritic chest pain.[
6] However, some studies showed
that restrictive defect in pulmonary function observed
during the first 72 h after cardiac operations with CPB
was unaffected by the interference with the pleural
integrity.[
11,
19,
20] Another important finding in our study
is that FEVI/FVC values on the fifth postoperative
day did not significantly differ from preoperative
values, indicating a lack of significant pulmonary
obstruction (Table
2). All patients received chest
physiotherapy, as well as early mobilization, to prevent
retention of secretions to be a source of decrease in the
functional residual capacity (FRC) or atelectasis.[
21]
In the evaluation of arterial blood gas values, some
authors reported a negative influence of pleurotomy
in the PaO
2 and PaO
2/FiO
2 during on-pump CABG
with the use of the left internal mammary artery
(LIMA).[
16,
17] Unlike many other studies, decrease
in the PaO
2 occurred in both groups on the first
postoperative day and the decrease within the groups
did not significantly differ (p>0.05) (Table
3).
In a meta-analysis of 19 randomized-controlled
studies comparing IMA harvesting with intact versus
open pleura, all patients demonstrated significant
deterioration in the pulmonary function tests and
radiographic appearance postoperatively.[20] Although
pleurotomy seemed to have increased rates of atelectasis
and effusions, the study showed no impact on clinical
outcomes and length of hospital stay. As in our study,
we found no impact on the postoperative outcomes.
In contrast to these findings, decrease in the lung
volume, as well as FRC, atelectasis and postoperative
reduction of the PaO2 were similar. We observed no
complications directly related to pleurotomy. Many
studies showed that the incidence of atelectasis was
limited in preserved pleural integrity,[20,21] although there was no significant difference in the atelectasis
rate of our patient groups. We believe that it could
be due to pain-related breath restriction and mucus
retention, leading to atelectasis. Unlike most
published researches, we believe that pleurotomy
reduces some adverse effects, such as tamponade or
pneumothorax, in the early postoperative period.
Another issue related to oxygenation is the placement
of pleural drainage tube or thoracostomy tube and it
has been shown that such a procedure is associated
with decreased oxygenation secondary to chest wall
pain, splinting, and reluctance of the patient to
cough, sigh, and taking deep breaths.[21] Some authors
reported that pleural effusion was more common
following the LIMA harvesting.[4] Other studies,
unlikely, found that pleural effusion occurred with
the same frequency after CABG, even in the absence
of the LIMA harvesting.[22] However, Labidi et al.[23]
reported 11.9% incidence of symptomatic pleural
effusion in their prospective study. We showed that
the pleural integrity has no effect on pleural effusions
(Table 4). Both groups of this study consisted of
patients undergoing IMA harvesting, as well as
valve surgery. This result has been also supported by
findings of Iskesen et al.[8] showing that preservation
of the pleural integrity during LIMA harvesting
did not have any effect on atelectasis or pleural
effusions. Lim et al.[9] divided 206 patients into three
groups: isolated CABG patients (n=138), valve surgery
patients (n=39), and combined procedure patients
(n=29). Although patients with a left pleurotomy
(n=164) had a higher incidence of left lung atelectasis
(67.7% vs. 45.2%, respectively; p=0.007), there was no
significant difference in pleural effusion (42.5% vs.
46.3%, respectively; p=0.66) and these results were
not associated with an adverse clinical outcome.
It is crucial that postoperative bleeding, which was
fewer with the preserved pleural integrity (p=0.003)
in our study, has been shown in many studies.[7,8]
Excessive bleeding in our opened pleurotomy group
did not cause any pulmonary complications. Besides,
postoperative anticoagulation in valve operations
may increase the risk for cardiac tamponade, and
pleurotomy may act as a safeguard against such
a complication. This study found no significant
association between bleeding and cardiac tamponade.
We excluded patients with previous lung disease, such
as chronic obstructive pulmonary disease, to prevent
possible source for a higher incidence of respiratory
related complications.
Nonetheless, there are some limitations to our
study that we were unable to measure postoperative
long-term respiratory tests to detect changes over
time. On a chest X-ray, it can be difficult to identify
atelectasis visually. However, uniform analysis was
used to avoid bias of data evaluation.
In conclusion, our study results suggest that opened
pleura seems not to be associated with a higher
incidence of pulmonary complications, compared
to the intact pleura. However, further large-scale,
prospective studies are needed to establish a definitive
conclusion.
Declaration of conflicting interests
The authors declared no conflicts of interest with respect
to the authorship and/or publication of this article.
Funding
The authors received no financial support for the research
and/or authorship of this article.