Preoperative and Postoperative Spirometry in Patients Undergoing Lobectomy for Sequelae of Pulmonary Tuberculosis ()
1. Introduction
Tuberculosis (TB) remains common in some countries including Brazil [1]. TB continues into the 21st century as an unresolved public health problem representing an important cause of morbi-mortality [2]. It is the most common infectious disease in humans [3] and the cause of death in around 3 million people worldwide annually, being the third most prevalent infectious disease but having the highest death rate [4]. TB is perhaps the oldest disease known to man, with records of lesions found in the vertebrae of Egyptian mummies dating back almost four thousand years [5-8].
Currently, TB is placed in a unique epidemiological and socioeconomic context characterized by a global demographic transition which has led to a marked aging of the population [1,9].
Diagnosis of disease activity in patients with pulmonary tuberculosis (PTB) is based on multiple factors such as clinical status, physical exam, tuberculin test and mainly on the detection of the bacillus in sputum, bronchialveolar lavage, transtracheal aspirate or lung tissue biopsy samples. These factors are supported by others such as sequential changes on chest radiographs and previous history of anti-tuberculosis therapy [1,10].
With the advent of modern chemotherapy, a dramatic reduction in tuberculosis ensued, commencing with the discovery of streptomycin in 1944 and the anti-tuberculosis activity of isoniazid in 1952 [11,12].
The most frequent sequelae of tuberculosis are lung damage, bronchiectasis, fungal ball, tracheal stenosis in addition to other less common sequelae [13].
The pulmonary function test, ventilatory test or spirometry, is extremely important for indications of surgical treatment because it is used to assess whether the patient can tolerate anesthesia and if morbimortality is increased. [14]
Specifically for tuberculosis, a frequently occurring disease in Brazil, particularly in Maranhão state, few references are available in the literature of studies investigating alterations in lung function after resection of the parenchyma [15].
The School of Medical Sciences of the Santa Casa de São Paulo Hospital (FCMSCSP), among their research lines, is currently conducting studies involving the assessment of preoperative and postoperative pulmonary function tests. Many of these studies have been concluded [16-19].
Against this background, and providing continuity to the line of research pursued by the institution, we sought to assess preoperative and postoperative spirometry values in patients undergoing lobectomy for sequelae of previously treated pulmonary tuberculosis. This is the first study of this nature ever undertaken in our medical setting.
2. Method
The study was approved by the Research Ethics Committee of the Hospital Universitário Unidade Presidente Dutra—HUUFMA.
A total of 20 patients (10 males) with history of treatment for tuberculosis and presenting with symptomatic sequelae i.e. repeat infection or hemoptysis, who sought the chest surgery outpatient clinic of the Hospital Universitário Presidente Dutra of the Federal University of Maranhão between 11.09.07 and 04.02.10, were selected for the study.
In the sample studied, patient age ranged from 15 to 56 years (mean = 3575 years), the treatment time for tuberculosis was 06 months and onset of symptoms occurred between 01 and 32 (mean = 7.8 years) years after treatment.
After clinical interview with reporting of recurrent hemoptysis and previous history of treated tuberculosis, chest radiograph and CT exams were ordered.
With radiologically-confirmed diagnosis of sequelae, pre-operative exams were requested: perfusion scintigraphy and pulmonary ventilation, sputum stain test for acidfast bacilli, blood analyses, cardiologic assessment and pulmonary function tests (PFT).
Pulmonary Function Tests
The volume-time curve obtained by forced spirometry was performed according to the criteria standardized in 1995 by the American Thoracic Society (ATS) [20], with the best of three acceptable curves chosen. Forced vital capacity (FVC), forced expiratory volume in one second (FEV1), forced expiratory flow (FEF) between 25% - 75%, FEV1/FVC ratio, and peak expiratory flow (PEF) values were derived from the best curve. The normative reference values proposed by Pereira et al. in 2001 were used for all curves [21].
The comparison of impact of surgery on the variables (VC, FVC, FEV1, FEV1/FVC, FEF and PEF) at the 1st, 3rd, 6th and 12th month post-operatively versus preoperatively, was performed using the paired t test. The level of significance (a) applied for all tests was 5%, i.e. was deemed significant at p < 0.05.
3. Results
3.1. Interventions
11 patients were treated because of recurrent infections and 9 because of haemoptysis. The most common lobectomy was right upper lobectomy (7 patients), followed by left upper lobectomy (6 patients), left lower lobectomy (6 patients), and right middle lobectomy (1 patient). Therewere no postoperativecomplications. There was no postoperative mortality.
3.2. Vital Capacity
The mean VC value significantly decreased post-operatively from 2.83 L preoperatively to 2.12 L at the first postoperative month. It progressively increased to 2.43 L six months postoperatively, but differences still remained statistically significant compared with preoperative values (Figure 1).
Figure 1. Mean vital capacity (VC) values with standard deviations and calculated “p” values for comparison of preoperative and postoperative periods. A significant difference (p < 0.05) was observed in the means of the preoperative and postoperative periods for all three comparisons (preoperative and first month, preoperative and third month, preoperative and sixth month).
3.3. Forced Vital Capacity
As with VC, the mean FVC value also decreased one month after resection to progressively increase thereafter. However, at the sixth postoperative month, it still was significantly lower than the preoperative value (Figure 2).
3.4. Forces Expiratory Volume in One Second
The comparison of the mean values of FEV1 showed no statistically significant differences between the preoperative value and the value at six months postoperatively. However, there were statistically significant differences when the preoperative value was compared with those at the first and third postoperative months. In this case, a progressive recovery was observed during the first six months after lobectomy (Figure 3).
Figure 2. Mean forced vital capacity (FVC) values at the four timepoints: One preoperative and three postoperative. A statistically significant difference was found on comparison of the four timepoints (p < 0.05).
Figure 3. Mean forced expiratory volume in one minute (FEV1) values of the four timepoints: one preoperative and three postoperative. No statistically significant difference (p > 0.05) was found between the preoperative value and that at sixth months postoperatively, but a significant difference (p < 0.05) was evident for the other two comparisons (preoperative versus first month and preoperative versus third month). A progressive recovery of values was observed.
3.5. Peak Expiratory Flow
A significant decrease in PEF was observed across the postoperative period, with no significant recovery at six months postoperatively (Figure 4).
3.6. Forces Expiratory Volume in One Second/Forced Vital Capacity
Figure 5 depicts the mean values of FEV1/FVC of fourstages: pre-and postoperatively. There was nostatistically significant differences (p > 0.05) when compared with preoperative values. For this test, full recovery occurred six months after resection.