ESTIMATION OF TRACHEOBRONCHIAL TREE CONDITION IN PATIENTS WITH POLYTRAUMA DURING FIBRO-TRACHEO-BRONCHOSCOPY FOR PREDICTION OF COMPLICATIONS Kravtsov S.A., Zaikin S.I., Frolov P.A.
Regional Clinical Center of Miners’ Health Protection, Leninsk-Kuznetsky, Russia
Bronchopulmonary complications are the triggers for development of multiple organ dysfunction/insufficiency in polytrauma. Aspiration of food and blood to the lumen of the tracheobronchial tree, acute tracheobronchitis, nosocomial and ventilator-associated pneumonia are noted within three days in 26-65 % of patients [1]. All these events are accompanied by increasing hospital stay and costs for treatment. The mortality in aspiration syndrome and nosocomial pneumonia achieves 40-70 % in patients with aspiration syndrome and nosocomial pneumonia [2, 3].
The main diagnostic and curative technique for examination of the tracheobronchial tree in patients with severe associated injury is fibro-tracheo-bronchoscopy (FTBS). FTBS allows examining the trachea and bronchi of the first and third order, as well as removal of pathologic contents from their lumen and correction of lung atelectasis. Airway management decreases the risk of pulmonary complications by 30 % [4]. FTBS has some disadvantages for critically ill patients [5], but it is still required for diagnostic and curative procedures in severe associated injury. Considering the polymorphism of pathology in polytrauma, some tasks are still unsolved: the features of development of bronchopulmonary complications in dependence on a dominating pathology, influence of various modes of respiratory support on their severity, required frequency of examination, duration etc.
The objective the study – to estimate the possibilities of diagnostic and curative fibro-tracheo-bronchoscopy (FTBS) in patients with polytrauma with determination of the risk factors influencing on the course and prognosis of endobronchitis.
MATERIALS AND METHODS
The prospective study included 121 patients with polytrauma. The patients received the treatment in the intensive care unit, Regional Clinical Center of Miners’ Health Protection, within the period from January 2014 till December 2016.
All examinations with participation of the patients corresponded to the ethical standards of the bioethical committee in concordance with WMA Declaration of Helsinki - Ethical Principles for Medical Research Involving Human Subjects, and with the Rules for clinical practice in the Russian Federation confirmed by the order by the Health Ministry of Russia from June 19, 2003, No.266.
The main inclusion criteria were time from the accident ≤ 24 hours, ALV duration ≥ 72 hours, severity of injury and condition. Injury Severity Score (ISS) was used for estimating the severity of injuries. It was 24.8 ± 0.7. The patients’ condition severity was estimated with APACHEII (Acute Physiology and Chronic Health Evaluation). It was 21.8 ± 1.4. The exclusion criteria were the age < 18 and agonal state.
Depending on a dominating injury, the patients were distributed into five groups: the group 1 – the patients with dominating spine and spinal cord injury (DSSCI) (n = 19); the group 2 – the patients with dominating thoracic injury (DTI); the group 3 – the patients with dominating abdominal injury (DAI) (n = 15); the group 4 – the patients with dominating skeletal injury (DSI) (n = 15); the group 5 – the patients with dominating traumatic brain injury (DTBI) (n = 43) [6]. Retrospectively, each group was divided into two subgroups – with favorable (the subgroup A) and unfavorable (the subgroup B) outcomes (the table 1).
In the early posttraumatic period, under endotracheal narcosis, the various surgical interventions were conducted. The interventions were for arresting bleeding, restoration of integrity of hollow organs, correction of intracranial compression, fixation of fractures etc.
Most patients were the men (72.7 %) of working age (18-74 years). The mean age was 38.1 ± 1.1 (the table 2). All patients received ALV with the modern microprocessor respirators. According to the concept of “safe ALV”, we used the pressure controlled ventilation (PCV). The planned transition to spontaneous breathing was realized with synchronized intermittent mandatory ventilation (SIMV) and with respiratory support in the mode of assisted spontaneous breathing (ASB). The breathing circuit was changed at least 1 time per 24 hours. The continuous monitoring of the main parameters of hemodynamics, gas exchange and acid-base balance of the blood was conducted with the gas analyzer Omni S (Roche, Germany) including the estimation of oxygenation index (PaO2/FiO2, mm Hg).
The condition of the tracheobronchial tree was estimated on the days 1, 2, 3, 5, 7, 14 and 21 after the injury with use of FTBS and microbiological examination of bronchial lavage. The fiber optic bronchoscopes were used for diagnostic and curative FTBS: EB-157K (Pentax, Japan) with the external diameter of 5.1 mm and the instrumental canal diameter of 2 mm; BF-1T60 (Olympus, Japan) with the external diameter of 6.0 mm and the instrumental canal diameter of 3.0 mm. The obligatory presence of the special trochanteric connector in the breathing circuit allowed minimizing the unfavorable effects of its decompression by means of a rubber membrane of the connector with prevention of leak of oxygen-air mixture during introduction of the bronchoscope.
During visual examination of the tracheobronchial tree we considered the intensity and location of hyperemia, the intensity and the incidence of mucosa edema, the characteristics and amount of secretion, presence of gastrointestinal contents in the bronchial and tracheal lumen, blood in bronchial secretion, mucopurulent plugs obstructing the bronchial lumen. The endobronchitis degree was estimated with the classification by J. Lemoine (1965) with amendments by G.I. Lukomskoy et al. (1982) [7].
Bronchoalveolar lavage (BAL) was used for collection of the specimen for cytological and microbiological examination. During BAL, the distal end of the bronchoscope was introduced into one of the main bronchi. The sterile saline (10 ml) was introduced through the endoscope’s channel into the bronchial lumen, with subsequent aspiration into the sterile container. If pathologic secretion was visualized in the bronchial lumen, then it was removed before BAL. The sanitation bronchoscopy technique included the segmental microlavage – irritation with a solution (10-20 ml) with subsequent aspiration of airway contents. We used the saline as a solution for lavage (the temperature of 36-37 °C). It does not have any side-effects, does not influence on rheology of the mucus (with decreasing its superficial tension) that simplifies the natural evacuation and allows appropriate aspiration.
StatSoft Statistica 6.1 (the license agreement BXXR006D092218FAN11) was used for statistical analysis of the results. The mean arithmetic (M) and the standard error of the mean (m) were calculated. Mann-Whitney test was used for estimating the statistical significance of differences. χ² test and the contingency tables were used for comparison of quantitative signs; for the group with less than 10 – z-test and Fisher’s exact test. The p value < 0.05 was considered as statistically significant. The regression analysis with binary logistical regression was used for identification of the most significant factors that could predict development of complications. IBM SPSS Statistics v20.Windows (SPSS Inc., Chicago, IL, USA) was used for production of the binary logistical model.
RESULTS
All patients with ALV received the diagnostic and sanitation FTBS procedures (the total amount of 1,426) from the admission moment and through the whole period of ICU stay. The mean period of ICU stay was 19.7 ± 8.1 days. Progressing atelectasis develops in many patients after long periods of controlled or assisted breathing. This phenomenon reflects the absence of “physiological” positive end-expiratory pressure (PEEP). Independent breathing under insignificant positive pressure (up to 5 cm of H2O), which is created by the larynx in normal conditions, allows preventing the atelectasis and supporting the adequate functional residual capacity (FRC). The main indication for positive airway pressure is a clinically significant decrease in FRC resulting in relative or absolute hypoxemia. Owing to increase in spreading transpulmonary pressure, the positive airway pressure allows increasing the pulmonary volume, improving the lung compliance and normalizing the ventilation/perfusion disorders. The last mentioned event is characterized by decreasing shunt fraction and increasing PaO2. The mean time of ALV/AALV was 12.7 ± 6 days. The PEEP mode (8-14 mm of H2O) was used according to the indications. We did not find any statistically significant differences in duration of ALV in the patients with favorable or poor outcomes (the table 3). The mortality was 23.9 % (29 persons). The postmortem examination confirmed tracheobronchitis in all cases with pneumonia.
The diagnostic FTBS identified endobronchitis in 62 % of the cases during the first day. Depending on a dominating pathology, which influenced on the pathogenesis of bronchopulmonary pathology, the degree of its intense depended on the following factors: pulmonary aspiration of gastric contents was in 45 patients (37.2 %), traumatic bronchial injury – in 25 (20.7 %) (Fig. 1), bronchial lumen obturation – in 17 (14.1 %) (Fig. 2).
The highest amount of bronchoscopy procedures was conducted for the patients with DSSCI (579 cases, 40.6 % of all FTBS, p = 0.0004) (the table 4). In case of DSSCI, pulmonary aspiration of gastric contents was identified more often (57.9 %, p = 0.0312) (Fig. 3). Pulmonary aspiration of gastric contents was identified in 25 %, bronchial injury – in 17.4 %, bronchial obturation – in 17.4 % of the cases in the subgroup A. In the subgroup B, pulmonary aspiration of gastric contents was identified in 75.9 %, bronchial injury – in 3.4 %, bronchial obturation – in 31.0 % of the cases. The high rates of traumatic bronchial injuries (up to 20 %) were noted in the group with dominating skeletal and traumatic brain injury. It was associated with concomitant thoracic injuries.
During the first day of the observation, all patients demonstrated the signs of inflammation in the tracheobronchial tree including the changes in the vascular pattern, hyperemia and edema of mucosa, presence of mucous or mucopurulent secretion. The endoscopic appearance of the tracheobronchial tree corresponded to endobronchitis of degree 1 and 2 in 43.1 and 56.9 % correspondingly in the group with favorable outcomes in the first day of the follow-up. The group of poor outcomes showed endobronchitis of degree 2 and 3 in 86.4 and 13.6 %. On the third day of the follow-up, the patients with poor outcomes showed the increase in inflammation of the tracheobronchial tree with manifestations including the increase in mucosa edema and changes in bronchial secretion (endobronchitis of degree 2 in 37.8 %, endobronchitis of degree 3 in 62.2 %). The visual examination of the tracheobronchial tree corresponded to endobronchitis of degree 1 in 19.6 %, endobronchitis of degree 2 in 57.9 % and endobronchitis of degree 3 in 22.5 % in the patients with favorable outcomes.
At the same time interval, endobronchitis of degree 3 was diagnosed in the patients with DSSCI in 68.4 %, with DAT – in 53.3 %, with DTI – in 51.7 %, with DTBI – in 34.9 %, with DSI – in 26.7 % (Fig. 4).
Within the period from 5th to 7th day of the study, the maximal intensity of inflammatory changes was registered in the groups with the tracheobronchial tree corresponding to endobronchitis of degree 3 in 30.5 % of the patients with favorable outcomes and in 93.1 % of the patients with poor outcomes. According to the bacteriological analysis, the most common causative agents of tracheobronchitis and pneumonia in all patients were Klebsiella pneumonia, Pseudomonas aeroginosa, Acinetobacter baummanii, Enterobacter aeroginosa, Staphylococcus aureus, Staphylococcus auricularis. We did not find any differences in the qualitative and quantitative composition of microflora in the patients with favorable and poor outcomes. The results of the regression analysis confirmed our assumption about pulmonary aspiration of gastric contents as a main cause of endobronchitis of degree 3 (area under curve (AUC) = 0.742) (Fig. 5).
The logistic regression analysis (including the following parameters: age, gender, type of a dominating injury, pulmonary aspiration of gastric contents, traumatic bronchial injury, bronchial lumen obturation, endobronchitis degree) showed endobronchitis of degree 3, pulmonary aspiration of gastric contents and traumatic bronchial injury as the independent factors of a poor outcome in the patients with polytrauma (the table 5).
During sanitation FTBS, we did not find any significant changes in the parameters of hemodynamics and pulmonary gas exchange. The oxygen saturation (SpO2) was within the normal range (97.9 ± 1.05 % before FTBS vs. 97.3 ± 1.74 % after FTBS, p > 0.05). The maximal decrease in SpO2 by 5 % was noted in 16 patients. In other patients, saturation decreased by more than 3 %. The changes in the oxygenation index (PaO2/FiO2) depended on the main pathology. The medical diagnostic procedures did not influence on their course.
DISCUSSION
Many authors consider FTBS as the independent predictor of intrahospital pneumonia in the intensive care unit, and a dangerous procedure from the perspective of epidemiology [3, 5]. The literature does not contain any reports on the rate of FTBS-associated complications in critically ill patients in the total group of such complications. The attitude towards the technique of FTBS (amount, quality, timing, safety) in acute period of the disease of injury in critically ill patients, as well as the changes in central hemodynamics or gas exchange present the poorly studied problem and are insufficiently described in the medical literature. All surgical patients in acute phase of a disease have some syndromes relating to respiratory and hemodynamic hypoxia, hypoxia of high vascular resistance, hypoxia of low cardiac output and other events mediated by systemic and cerebral hypoxic disorders. Moreover, in acute phase of the disease, all patients receive artificial lung ventilation that can cause some inflammatory complications. The bronchopulmonary complications appearing in such patients include nosocomial pneumonia, acute and chronic tracheobronchitis (catarrhal, purulent), atelectasis and acute respiratory distress syndrome (ARDS).
Diagnostics and treatment of bronchopulmonary complications in patients with polytrauma present the complex of the procedures, which are based on the elimination of the triggering moments causing pathologic conditions, and on provision of maximal capability of the respiratory system in realization of its main function [8, 9]. From these perspectives, FTBS is one of the key techniques promoting the achievement of the indicated objectives. FTBS provides the visual assessment of the trachea and bronchi, and a possibility for acquisition of the cellular elements – the markers of lesion of the bronchoalveolar system [10]. In patients with polytrauma and bronchopulmonary complications, the essential task is restoration of adequate patency of bronchi for improvement in gas exchange and prevention of infiltrative-inflammatory processes in the lungs [11]. Despite the fact that FTBS is currently used in ICU for treating tracheobronchitis and pneumonia with sanitation of the tracheobronchial tree and identification of the causal agents, some authors note the negative influence of FTBS on the parameters of central hemodynamics and ventilation values of the lungs and, as result, on gas composition of the blood [12, 13, 14]. In our study we used FTBS in conditions of pharmaceutical protection and 100 % oxygenation without the breathing circuit decompression. The procedure of curative FTBS was realized in dosed manner. The duration of a single procedure with the fiber optic bronchoscope in the bronchial lumen did not exceed 20-25 sec. We did not note any FTBS-associated complications. Timely and efficient diagnostics of the bronchial obstructive component (including complications of pulmonary aspiration of gastric contents), development and the course of tracheobronchitis in patients with polytrauma allow determining the complex of medical measures oriented to restoration and maintenance of adequate patency of airways.
CONCLUSION
1. All patients with polytrauma should receive fibro-tracheo-bronchoscopy for diagnostics, timely treatment and prevention of bronchopulmonary complications from the first day of artificial lung ventilation.
2. With use of fibro-tracheo-bronchoscopy in the first day, all patients showed some inflammatory changes in the tracheobronchial tree. Their intensity reached the maximal level from 5th to 7th day of artificial lung ventilation. The main cause of endobronchitis of degree 3 was pulmonary aspiration of gastric contents.
3. The independent risk factors of poor outcome in patients with polytrauma were endobronchitis of degree 3, pulmonary aspiration of gastric contents and traumatic bronchial damage. Traumatic bronchial injuries are more common in patients with severe skeletal and thoracic injuries as result of their concomitant pattern.
Information about conflict of interests
The study was conducted without sponsorship. The authors declare the absence of any clear and potential conflicts of interests relating to publication of this article.