City Clinical Hospital #1,

Novokuznetsk State Institute of Postgraduate Medicine, 

Novokuznetsk, Russia

Severe concomitant injury (SCI) and severe burn injury (SBI) are complex and actual problems of modern medicine. One of the leading complex tasks is control of main disease and frequent bronchopulmonary complications in view of acute respiratory distress syndrome (ARDS), acute tracheobronchitis, nosocomial and ventilator-associated pneumonia [1-4]. High mortality in SCI is associated with both abdominal injuries in acute traumatic period and development of mutual burdening syndrome and multiple systemic complications in posttraumatic period [1]. In patients with SBI development of bronchopulmonary complications, as well as sepsis and extensive burn wounds, is one of the main factors determining severity of state and significantly increasing hospital stay and costs for treatment [4]. Therefore, need for sanation and diagnostic fibertracheobronchoscopy (FTBS) remains equal in patients with SCI and SBI. However, the attitude to technique realization is non-unique (quality, amount, time, safety). It is known that FTBS impacts cardiovascular and respiratory systems and is not safe, but changes in central hemodynamics in these patients’ groups and complications are poorly described in literature [5].

The research of the study was comparative estimation of systemic hemodynamics during artificial lung ventilation for specification of indications and contraindications to sanitation FTBS in patients with SCI and SBI.

 

MATERIALS AND METHODS

The prospective cohort study included 41 patients with SCI and SBI. 56 FTBS procedures were performed during ALV. All patients were distributed into two groups. The first group included 26 patients (63.4 %) with SCI, mean age of 39.6 ± 2.4, with 34 FTBS procedures. Severity of injuries was 23.4 ± 0.6 according to ISS, severity of state ‒ 21.9 ± 1.7 according to APACHE-II. 19 patients (73 %) received different surgical interventions for stabilization of bone fractures, restoration of hollow organs, bleeding arrest, pleural cavity draining et al. (in early posttraumatic period under endotracheal anesthesia).

The second group included 15 patients (36.6 %) with SBI, age of 40.1 ± 3.2. They received 22 FTBS procedures. The burning area was > 30 % for each patient, 77.4 ± 10.5 % on average. With Frank index < 30 c.u., APACHE-II was 22.3 ± 1.3 on the first day after admission.

A stage of acute respiratory distress syndrome (ARDS) was defined with the classification by V.V. Moroz and A.M. Golubev [6].

All patients received ALV with modern microprocessor respirators. According to the concept of “safe ALV”, pressure controlled ventilation (PCV) was used followed by auxiliary mode with pressure support (PS) (by means of synchronized intermittent mechanical ventilation [SIMV]) and ALV weaning.

All examinations were carried out on days 1-7: clinical estimation of patient’s state, monitoring for basic hemodynamic indices, biochemical examination of biologic fluids (blood, urine), acid-base balance, instrumental methods (computer tomography, X-ray imaging, diagnostic laparoscopy).

Along with the generally accepted techniques, we examined central hemodynamics functional state with transpulmonary thermodilution (PiÑCOPlus monitor, PULSION medical system, Germany) for early identification of cardiac insufficiency and estimation of adequacy of infusion therapy in correction of volemic disorders with assessment of cardiac index (CI), systemic vascular resistance index (SVRI), heart rate (HR), systolic, diastolic, mean arterial pressure (SAP, DAP, MAP), extravascular lung water index (EVLWI) and global end-diastolic volume index (GEDVI).

The examination of gas exchange and blood acid-base balance was realized with the gas analyzer SÒÀÒ FÀÕ-ÐÍ ÎÕ, Novabiomedical (USA) with estimation of oxygenation index (ÐàÎ₂/FiÎ₂, mm Hg).

The inclusion criteria were hypoventilation because of bronchial obstructive syndrome confirmed by clinical and X-ray data, blood gas contents and decreasing peripheral saturation. Endobronchitis severity (degree, localization and incidence of mucosal inflammatory process, characteristics and amount of excreta) was assessed with the classification by J. Lemoine (1965) supplemented by Lukomsky G.I. et al. (1982) [7]. Degree of hypotonic bronchial dyskinesis and cough reflex disorders were estimated with the recommendations by M.I. Perelman (1974); the estimation was performed at tracheal bifurcation level after tracheal introduction of 1 ml of 0.5 % dioxidine solution (for cough stimulation). For endoscopic manipulations the fiberotic bronchoscope BF-1T60 (Olympus, Japan), the external diameter of 6 mm and the instrumental diameter canal of 3 mm, was used. The obligatory condition for FTBS was special acetabular connector in breathing circuit that allowed minimizing unfavorable effects of pressure leak. The fiberoptic bronchoscope was introduced through the hole in connector rubber membrane which prevented significant leak of oxygen air mixture during introduction of the device and decreasing lung airiness (alveolar collapse). During FTBS analgetic sedation was performed with seduxen (0.2-0.3 mg/kg of patient’s body mass) and local anesthesia with lidocaine (2 %, 10 ml).

Intensive care for the patients of the group 1 included general measures for artificial support of vital functions of organs and body systems (breathing, circulation, metabolism), specifically: surgical intervention, treatment of traumatic shock, correction and support of adequate gas exchange, correction of hemostasis disorders, prevention of gastrointestinal bleeding, adequate antibacterial therapy, nutritive support, analgetic sedation [8, 9].

The main directions of treatment for group II patients with burn toxemia and septic toxemia were deintoxication, normalizing disordered water-electrolytic balance, energetic loss fulfillment, protein provision, prevention and treatment of infectious complications, anemia, removing pain syndrome, normalizing breathing, circulation, volemic disorders, blood rheological properties and organ protection, protection of burned surfaces from infection [10].

The mean duration of ALV was 8.3 ± 1.5 days (7.1 ± 1.1 in the first group, 10.7 ± 1.6 days in the second group, p = 0.043).

Statistical analysis was performed with GraphPad InStat 3 certified software. Arithmetic mean (M), mean square deviation (δ), and standard error in mean (m) were calculated. Reliability of differences was estimated with Mann-Whitney test and Spearman rank correlation (r). P < 0.05 was considered as statistically significant.

 

RESULTS

The patients with SCI and SBI after FTBS demonstrated increasing CI in all cases (the first group, from 3.5 ± 0.09 L/min/m² to 3.79 ± 0.09 L/min/m², the second group, from 3.47 ± 0.12 L/min/m² to 3.89 ± 0.11 L/min/m², (p < 0.05) confirmed by absent cardiac insufficiency (table 1).

Table

Dynamics of changes in central hemodynamics and gas exchange in patients with SCI and SBI before and after FTBS  (M ± m)

However, the patients with SCI demonstrated increasing SVRI from 2,144 ± 89.4 dyne*sec.*cm^-5*m² to 2,319 ± 101.3 dyne*sec.*cm^-5*m² (the group I). The patients with SBI showed decreasing SVRI from 2,649 ± 101 dyne*sec.*cm^-5*m² to 2,494 ± 91.9 dyne*sec.*cm^-5*m² (group II) (p < 0.05). In all cases we noted increasing HR (the first group, 99.9 ± 2.1 beats/min to 111.4 ± 1.7 beats/min, p < 0.05, the second group, from 97.3 ± 2.4 beats/min to 116.3 ± 4.8 beats/min, p < 0.05). After FTBS all patients showed increasing GEDVI (the first group, from 490 ± 16 ml/m² to 518 ± 13 ml/m², the second group, 597 ± 19 ml/m² to 654 ± 21 ml/m², p > 0.1). These changes supposed relative hypovolemia in the groups I and II.

After FTBS both groups demonstrated increasing SAP and DAP (the first group, 126.3 ± 3.3 mm Hg to 140.6 ± 3.2 mm Hg and from 71.7 ± 2.03 mm Hg to 80.4 ± 1.6 mm Hg correspondingly, p < 0.05; the second group, from 130.3 ± 4.03 mm Hg to 144.2 ± 5.2 mm Hg and 73.6 ± 2.1 mm Hg to 80.4 ± 2.4 mm Hg, p < 0.05). In the patients with SCI, mean AP increased from 91.9 ± 2.1 mm Hg to 100.1 ± 1.6 mm Hg, in the group with SBI ‒ from 94.5 ± 2.4 to 103.4 ± 2.6 mm Hg (p < 0.05).

Before FTBS, EVLWI was 7.3 ± 0.16 ml/kg in the first group, after FTBS ‒ 7.4 ± 0.17 ml/kg (within reference values). In the second group EVLWI increased to 9.7 ± 0.26 ml/kg before FTBS, and 9.8 ± 0.29 ml/kg after FTBS (p > 0.05). These changes indicated presence of acute lung injury in patients with SBI. Absence of significant changes before and after FTBS is explained by low variability within short time period, which is required for endoscopic procedure.    

Peripheral saturation (SpO₂) after FTBS increased in all cases in the first group (from 94.1 ± 0.45 % to 98.4 ± 0.2 %). As result, oxygenation index (PaO₂/FiO₂) increased in the first group (from 224 ± 13 mm Hg to 234 ± 17 mm Hg, ð > 0.05).

In the second group PaO₂/FiO₂ increased only in the patients without thermal inhalation injury (54.5 % [12 cases], from 91.2 ± 1.21 % to 98.2 ± 0.3 %). In the patients with thermal inhalation injury pre- and post FTBS SpO₂ did not change in 45.5 % (10 cases) (91.2 ± 0.34 % and 90.6 ± 0.27 %, p > 0.05). In the patients without inhalation burn PaO₂/FiO₂ increased from 195 ± 16 mm Hg to 218 ± 19 mm Hg. In the patients with thermal inhalation injury the values decreased from 173 ± 26 mm Hg to 149 ± 23 mm Hg. It is confirmed with the identified correlation dependence between EVLWI and degree of bronchial mucosal edema in the patients with thermal inhalation injury (r = 0.67; ð = 0.03) (Fig. 1). The patients with SBI showed absence of correlation in variables (r = 0; null correlation) (Fig. 2).

Figure 1

The correlation between endobronchitis degree (G.I. Lukomsky) and extravascular lung water index in patients with thermal inhalational injury: r = 0.67; p = 0.03 (statistically significant direct dependence of middle degree)

Figure 2

The correlation between endobronchitis degree (G.I. Lukomsky) and extravascular lung water index in patients with severe concomitant injury: r = 0 (null correlation)  

 

In the group of SCI with ARDS of degree I, EVLWI was 6.8 ± 0.12 ml/kg, with ARDS of degree II ‒ 7.9 ± 0.15 ml/kg, with ARDS of degree III ‒ 9.1 ± 0.14 ml/kg. As result, in the patients with SBI and ARDS of degree I, EVLWI was 6.9 ± 0.14 ml/kg, with ARDS II ‒ 7.7 ± 0.13 ml/kg, ARDS III‒ 9.3 ± 0.16 ml/kg (Fig. 3).

Figure 3

ARDS stages in the groups of patients with SCI and SBI

During sanitation FTBS we noted weak cough reflex in 2 patients (7.7 %) in the group I, and in 5 patients (33.3 %) in the group II. The cough reflex was low effective for removing sputum out of tracheobronchial tree (cough reflex extinction). Tracheal and bronchial dyskinesia of degree 1-2 was found in 3 patients in the first group (11.5 %) and in 1 patient in the second group (6.7 %). During FTBS for the patients with SCI, changes in tracheal mucosa were unilateral and diffusive in 85.3 % (29 examinations). It was associated with chest injury (pulmonary contusion, rib fracture etc.) on the corresponding side. If such injury was absent, the changes were diffusive and bilateral. In the patients with SBI the changes in bronchial mucosa were bilateral and diffusive regardless of thermal inhalation injury presence.

Primary endoscopy identified the following inflammatory changes (G.I. Lukomsky) (Fig. 4) in the group I:

‒ diffusive unilateral inflammatory changes in mucosa (endobronchitis of degrees 1, 2) in 12 patients (46.1 %);

‒ diffusive bilateral inflammatory changes in bronchial mucosa (endobronchitis of degrees 1, 2) in 7 patients (26.9 %);

‒ diffusive unilateral inflammatory changes in mucosa with purulent excrete (degree 3, including obstructive component) in 2 patients (7.7 %);

‒ diffusive bilateral inflammatory changes in mucosa with purulent excrete in 3 patients (11.6 %);

‒ different atrophic changes in bronchial mucosa (subatrophic, atrophic bronchitis) and absent pathology in 2 patients (7.7 %).

Figure 4

The state of bronchial mucosa after primary FTBS in patients with SCI and SBI

As for the second group (Fig. 4):

‒ diffusive bilateral inflammatory changes in bronchial mucosa (endobronchitis of degree 1, catarrhal bronchitis) in 7 patients (46.7 %);

‒ diffusive bilateral inflammatory changes in bronchial mucosa (endobronchitis of degree 2, including erosions, fibrin and ash accumulations, fibrous bronchitis) in 3 patients (20.0 %);

‒ diffusive bilateral inflammatory changes with purulent excrete and obstructive component (degree 3, including erosions, fibrin and ash accumulations, purulent bronchitis) in 3 patients (20.0 %) with thermal inhalation injury and without it;

‒ different atrophic changes in bronchial mucosa (subatrophic, atrophic bronchitis) and a type without pathology in 2 patients (13.3 %).

Gastric content aspiration into airways was observed in 8 patients (23.3 %) in the group I.

The mean period of ICU stay was 17.3 ± 8.2 days in the group of SCI, and 21.4 ± 7.6 days in the group of SBI. The mortality was 26.9 % (7 patients) in the first group, 73.3 % (11 patients) in the second group (p < 0.05). Pneumonia was found in all cases during postmortem examination.                   

 

DISCUSSION

Critically ill patients with injuries (concomitant skeletal or burn injuries) on ALV need for diagnostic and sanitation bronchoscopy. Contamination and purulent inflammatory processes are stimulated by changes associated with burn disease, long term ALV, intrahospital infection, and thermal inhalation injury, which presents in a half of patients [1-4, 11, 12]. In extensive and deep burns systemic pathologic changes result in microcirculatory disorders in tracheobronchial tree mucosa and immunosuppression favoring contamination and developing purulent inflammation in respiratory tract [4, 11]. Similarly, in SCI, the relationship is found between frequency, severity of bronchopulmonary complications and characteristics of injuries to systems and organs associating with traumatic disease. According to the literature data, ARDS is the most frequent complication of severe concomitant injury [5, 13, 14].

However FTBS can be dangerous for critically ill patients. In our study we found that FTBS (with pressure loss in breathing circuit) can worsen state by means of gas exchange disorder in the patients with ARDS signs. It is common knowledge that respiratory obstructive disorders are indications for FTBS. From other side, we know that restrictive disorders are contraindications. Clinically, differentiation between restrictive and obstructive disorders is possible with monitoring for mechanical properties of the lungs with servo fan (thoracic pulmonary compliance, airway resistance) and EVLWI.

According to the literature data, patients with SCI demonstrate increasing physiologic indices of EVLWI after 6-8 hours, whereas X-ray signs of acute lung injury (ALI) are not found at this time, and signs of interstitial and alveolar edema are registered after 2-3 hours post injury [14]. We believe that increasing EVLWI > 9 ml/kg testifies restrictive mechanisms of respiratory insufficiency in patients with SCI; FTBS is to be avoided in such cases.

Contrary to SCI, patients with SBI are characterized with thermal inhalation injury in some cases (45.5 %) that significantly worsens burn disease course [15]. Increased EVLW in patients with SBI is a predictor for worsening gas exchange in view of decreasing PaO₂/Fio₂ after FTBS compared to patients with SCI. Moreover, patients with SBI show signs of vascular bed spasm (increased SVRI) in relatively normal values of GEDVI and CI, and during FTBS the tendency exists in view of decreasing and normalizing SVRI, normalizing CI and GEDVI that testified safety of FTBS in these patients. Increasing values of SAP, DAP and mean AP was moderate and resulted in previous values within an hour after FTBS. However EVLWI increase above 9 ml/kg in normal values of volume preload (GEDVI) is an early predictor for ALI and is accompanied with low PaO₂/FiO₂ in patients with SBI. FTBS is non-rational and even dangerous in this case, because it results in progressing non-cardiogenic pulmonary edema. Therefore, above mentioned changes are contraindications for FTBS in acute period of SBI.

 

CONCLUSION

1. Acute respiratory distress syndrome (increased EVLWI) is the contraindication for fibertracheobronchoscopy in patients with severe concomitant and burn injuries. Thermal inhalation injury is accompanied with acute respiratory distress syndrome. Therefore, sanitation fiberbronchoscopy is not safe in this case, because of gas exchange disorders and hypoxemia.

2. A possibility of acute respiratory distress syndrome correlates with degree of bronchial mucosa edema in patients with thermal inhalation injury (r = 0.67; ð = 0.03).

3. There are differences in systemic hemodynamics response to fibertracheobronchoscopy. It depends on an injury type: AP, HR, CI and SVRI increase during fibertracheobronchoscopy in patients with severe concomitant injury. SVRI decreases in severe burn injury, with simultaneous increase in AP, HR and CI.                                   

4. Increasing CI is a favorable factor during FTBS, but its decrease indicates necessity for discontinuation.

 

List of abbreviations

 

AP (mm Hg) – arterial pressure

Mean AP (mm Hg) – mean arterial pressure

DAP (mm Hg) – diastolic arterial pressure

ALV – artificial lung ventilation

EVLWI (ml/kg/m²) – extravascular lung water index

GEDVI (ml/m²) ‒ global end-diastolic volume index

SVRI (dyne*sec.*cm^-5*m²) – systemic vascular resistance index

ALI ‒ acute lung injury

ARDS ‒ acute respiratory distress syndrome

SAP (mm Hg) ‒ systolic arterial pressure

CI (ml/min×m²) ‒ cardiac index

SBI ‒ severe burn injury

SCI ‒ severe concomitant injury

FTBS ‒ fibertracheobronchoscopy

HR ‒ heart rate

ÀÐÀÑÍÅ-II – Acute Physiology And Chronic Health Evaluation

ISS ‒ Injury Severity Score

FiO₂ ‒ fraction of inspired oxygen

PaO₂ (mm Hg) ‒ partial pressure of oxygen in blood

PaÎ₂/FiO₂ ‒ oxygenation index

PCV – Pressure controlled ventilation

PS – pressure support

SIMV – Synchronised Intermittent Mandatory Ventilation