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Kersin et al
Interestingly, it has been suggested that patients with this
association may also have bronchial hyperreactivity which
decreases with CPAP treatment.14 We also found that respiratory function parameters in patients with OSAS were negatively affected in our study. Large-scale studies are needed to
better understand the relationship between OSAS-bronchial
hyperreactivity and the outcomes of CPAP or surgical
treatment.
Although a number of studies have already examined pulmonary function parameters in patients with sleep apnea and
those using CPAP for sleep apnea, we performed this study due
to a lack of research regarding the effect of OSAS surgery on
respiratory function in the literature.
The first method that should be applied algorithmically to
patients with respiratory complaints is PFTs. The PFT plays a
role in determining the outcome of the disease, following the
course of the disease, by identifying the current functional
impairment and degree, illuminating the physiopathological
mechanisms responsible for the impairment of function.
Respiratory function has 4 main components: 1-ventilation,
2-diffusion, 3-perfusion, and 4-breathing control. Any disease
that affects the respiratory system may disrupt one or more of
these functions, leading to symptoms of the disease. Tests for
PFTs, ventilatory function of the lung and chest wall, tests for
gas exchange, and respiratory control tests are separated. In
clinical practice, tests related to ventilation and gas exchange
are most commonly used.15
Based on all this information, PFTs were utilized in our
study in order to evaluate the lung function of patients with
obstructive sleep apnea and multilevel surgery. The relationship between respiratory function and sleep apnea has been
investigated several times in the literature. Many studies have
also been conducted to explain the relationship between
respiratory functions and sleep apnea in nonsmoker patients
without any lung disease.16
The first study was performed by Sanders et al. All 11
patients with sleep apnea showed inspiratory and/or expiratory
flow oscillations.17 In addition, in 14 of 35 patients with sleep
apnea, extrathoracic upper respiratory tract obstruction was
detected in a study conducted by Haponik et al.18 The number
of patient groups in these 2 studies was limited. In later studies,
the patient population was higher. Smoking was not overlooked. However, flow-volume curves were not very useful
due to low sensitivity, low positive, and negative predictive
values.17,18
In a study with 170 patients, Zerah-Lancner et al. found a
significant decrease in FEV1/FVC, V50 (maximum flow rate in
50% of FVC), V25 related to OSAS severity (individuals with
BMI !35 were removed from study and the history of smoking
was not questioned).19
However, Gold et al. worked with 35 apneic patient groups
and 17 nonapneic control groups with appropriate demographic
characteristics. Forced expiratory volume 1/forced vital capacity values were not different between the 2 groups.20
In our study, we took measurements of the 5 basic parameters (FEV1, FVC, FEV1/FVC, PEF, and FEF 25-75) from

541
the group of 32 apneic patients and found significant improvement after surgery. Stauffer et al. had not demonstrated any
differences in FEV1/FVC and FEF 25-75 between 15 apneic
and 10 nonapneic control patients.21
In a study on the use of CPAP-one of the treatment modalities of OSAS-De Miguel et al. had demonstrated that there
may be a relationship between spirometry and OSAS in OVS.
In this study, OSAS treatment with CPAP showed significant
improvement in FEV1 values at 6 months.22 Parallel to this
study, we also found a significant increase in FEV1 after
surgery.
There were no significant differences between pre- and posttreatment FEV1 and FEV1/FVC values in 2 studies in which
spirometric evaluation was performed by Lin et al. after 4
weeks and 8 weeks of nasal CPAP therapy.23 In our study,
we performed spirometric measurements at 3 and 6 months
postoperatively and found significant improvement compared
to preoperative values.
On the other hand, prognostic effect of FEV1 was demonstrated in patients with OSAS who received nasal CPAP therapy.13 In our study, a significant improvement of FEV1 was
detected in the PFT performed at third- and sixth-postoperative
months. Similar to CPAP, surgical treatment also has positive
effects on the respiratory function and hence on the overall
prognosis of OSAS.13,23

Conclusion
In our study to evaluate pulmonary function before and after
robotic tongue base resection and uvulopharyngoplasty in
patients diagnosed with OSAS, we utilized PFTs, which are
the gold standard for assessing pulmonary function. Significant
improvements were obtained in all 5 postoperative parameters
(FVC, FEV1, FEV1/FVC, PEF, and FEF 25-75) in these
results. This study demonstrates the positive effect of robotic
tongue base resection and uvulopharyngoplasty on respiratory
function in the treatment of sleep apnea. In our study, surgical
treatment of OSAS showed positive effects on respiratory functions, similar to the effects of CPAP. There is, however, a need
for further and broader multicentered research on this topic.
Authors' Note
All procedures performed in studies involving human participants
were in accordance with the ethical standards of the institutional
and/or national research committee and with the 1964 Helsinki
declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants
included in the study, followed by a detailed explanation of the objectives and protocol of the study.

Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to
the research, authorship, and/or publication of this article.

Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
ENT - September 2020

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