Point-of-care endoscopic optical coherence tomography detects changes in mucosal thickness in ARDS due to smoke inhalation and burns.

BACKGROUND: The prevalence of acute respiratory distress syndrome (ARDS) in mechanically ventilated burn patients is 33%, with mortality varying from 11-46% depending on ARDS severity. Despite the new Berlin definition for ARDS, prompt bedside diagnosis is lacking. We developed and tested a bedside technique of fiberoptic-bronchoscopy-based optical coherence tomography (OCT) measurement of airway mucosal thickness (MT) for diagnosis of ARDS following smoke inhalation injury (SII) and burns. METHODS: 16 female Yorkshire pigs received SII and 40% thermal burns. OCT MT and PaO2-to-FiO2 ratio (PFR) measurements were taken at baseline, after injury, and at 24, 48, and 72h after injury. RESULTS: Injury led to thickening of MT which was sustained in animals that developed ARDS. Significant correlations were found between MT, PFR, peak inspiratory pressure (PIP), and total infused fluid volume. CONCLUSIONS: OCT is a useful tool to quantify MT changes in the airway following SII and burns. OCT may be effective as a diagnostic tool in the early stages of SII-induced ARDS and should be tested in humans.

[Clinical, radiological and bronchoscopic evaluation of inhalation injury cases treated at a burn center]. / Yanik merkezimizde takip edilen inhalasyon yanigi olgularinda, klinik, radyolojik ve bronkoskopik degerlendirme.

BACKGROUND: We aimed to introduce inhalation injury, pulmonary complications and mortality-related factors on the basis of clinical, radiological and bronchoscopic findings in patients with inhalation burns. METHODS: Between January 2009 and January 2010, patients hospitalized in the intensive care unit (ICU) of a burn center who were diagnosed as inhalation burn and underwent bronchoscopy were included in the study. Demographic findings, burn type, burn percentage, clinical-laboratory features, chest Xray findings on the first and fifth days, and bronchoscopic lesions were obtained from patient files. Bronchoscopic findings were classified, and bronchoscopic score for each patient was calculated. Clinical, laboratory and radiological findings, length of stay in the ICU, and bronchoscopic scores of patients who were discharged versus of those who died were compared, and mortality-related factors were investigated. RESULTS: Twenty-nine patients (25 male, 4 female; mean age 40.1 +/- 3.4 years) were included. Radiological abnormalities were found in 41.3% and 65.5% of patients on the first and fifth days of hospitalization, respectively. There were no complications related to bronchoscopy. Percentage of burn and duration of stay in the ICU were higher in patients who died than in discharged patients (20.4%-48.5%, p = 0.003; mean: 7.0-13.7 days, p = 0.037, respectively). Of patients who died, 79.1% showed radiological abnormality and 50% had acute respiratory distress syndrome (ARDS) on the fifth day of hospitalization. There were no pathologic findings on chest X-ray and no ARDS was seen on the fifth day in patients who were discharged (p < 0.05). CONCLUSION: Inhalation burns in patients with cutaneous burns cause a high percentage of pulmonary complications and increase mortality. Bronchoscopy must be performed early for diagnosis, and close follow-up of these patients is necessary.

Usefulness of technetium-99m hexamethylpropylene amine oxime lung scan to detect inhalation lung injury of patients with pulmonary symptoms/signs but negative chest radiograph and pulmonary function test findings after a fire accident--a preliminary report.

OBJECTIVE: In this study, we employed technetium-99m hexamethylpropylene amine oxime (99mTc HMPAO) lung scan to detect inhalation lung injury of patients after a fire accident. METHODS: Ten healthy men for controls and 10 male patients with pulmonary symptoms/signs from a fire accident were enrolled in this study for comparison. 99mTc HMPAO lung scan was performed in each control and patient, as well as the degree of pulmonary vascular endothelium damage was represented as lung/liver uptake ratios (L/L ratio). All of the controls and patients had no smoking histories. None of the controls and patients had positive findings of plain chest radiograph (CXR) and pulmonary function test (PFT). RESULTS: The results showed that significantly higher L/L ratio in the 10 patients (0.53 +/- 0.07) than in the 10 controls (0.30 +/- 0.07) (the p value < 0.05). Using a cut-off value of 0.40, all of the 10 patients had abnormally increased L/L ratios. CONCLUSIONS: We conclude that 99mTc HMPAO lung scan has the potential to be a sensitive, objective and noninvasive method to detect inhalation lung injury of patients with pulmonary symptoms/signs but negative CXR and PFT findings after a fire accident.

Radiological manifestation of pulmonary complications in deceased intensive care burn patients.

The chest radiographs of 46 burn patients who died in the burn intensive care unit (BICU) were retrospectively analyzed to study the spectrum of pulmonary complications and their contribution to patient's mortality. There were 25 male and 21 female patients and their mean ages were 34 and 30 years, respectively. Forty-three patients had flame burns, two chemical, and one scald with a mean total burn surface area (TBSA) of 71%. Thirty-six of them had inhalation injury and of these 25 patients developed septicaemia. Out of these 46 patients, 39 had a total of 60 pulmonary complications on various postburn days. The commonest complications were consolidation (28.3%) and adult respiratory distress syndrome (ARDS) (26.7%) mainly due to inhalation injury and/or following septicaemia. The majority of these complications (46.7%) occurred in the late phase (postburn day 5 onwards). Forty-one (89.2%) patients died due to multi-organ failure (MOF) and a good number of them had secondary respiratory failure. The flame burn patients with large TBSA, presence of inhalation injury, and occurrence of septicaemia, are at risk for pulmonary complications that equally affect adult males and females. Pulmonary complications irrespective of the cause significantly contribute to the mortality. This study suggests that serial chest X-rays done in BICU form an important diagnostic tool for pulmonary complications from postburn day 1 onwards, and is useful for subsequent monitoring of the treatment. All burn intensive care units may not be privileged to have a full time radiologist, and intensivist. Therefore, the burn surgeon needs to metamorphose into an intensivist and double as a burn radiologist for early detection and quick treatment if his surgical skills are to be adequately rewarded.

[Intrabronchial surfactant administration in inhalation trauma of severely burned patients with ARDS. Initial case reports]. / Intrabronchiale Surfactantapplikation bei inhalationstraumatisierten Schwerbrand verletzten mit ARDS. Erste Fallberichte.

Damage to the respiratory system caused by inhalation of toxic products of combustion and the subsequent development of adult respiratory distress syndrome (ARDS) are the main lethal factors in burns patients. Treatment with exogenous surfactant is one of the therapeutic options. However, no clinical reports have yet been published about this therapy. We report on two patients with burn injuries of second to third degree affecting 42% and 48% respectively of the total body surface plus inhalation injury complicated by ARDS. Both patients were treated with bovine surfactant (Alveofact). The therapeutic effects on oxygenation and pulmonary function were monitored. Intrabronchial application of surfactant by bronchoscopy during exhaustive conventional mechanical ventilation resulted in improved gas exchange with an increase in arterial O2 pressure (paO2); inspired O2 concentration (FiO2) was lowered and there was an improvement in lung compliance. Both patients survived this critical situation. We conclude that treatment with exogenous surfactant in postburn victims with ARDS is a promising therapeutic approach to improve the survival rate of these high-risk patients.

Clearance of aerosolized 99mTc-diethylenetriaminepentacetate before and after smoke inhalation.

The pulmonary clearance of aerosolized 99mTc-diethylenetriaminepentacetate (DTPA) was studied in mongrel dogs immediately after exposure to wood smoke to see if a sensitive, objective way of assessing the degree of pulmonary injury might be found. Animals were studied in four groups as follows: control, following five minutes, two minutes, and 15 seconds of smoke exposure. Chest roentgenograms and 133Xe scans were taken before and after smoke exposure. The DTPA clearance was more sensitive in detecting injury than either of these imaging techniques. The DTPA clearance rates increased in a dose responsive way following smoke inhalation: 2.4 percent and 12.1 percent excreted per minute for control animals and those exposed to five minutes of smoke, respectively. Seven patients in a clinical trial of DTPA following smoke exposure are described; their DTPA clearance rates were all normal, although five were active cigarette smokers. Despite encouraging results in animal experiments, DTPA clearance studies may be of little practical value in the clinical setting of acute inhalation injury.

Radionuclide evaluation of lung trauma.

Nuclear medicine imaging procedures can play a significant role in evaluating the pulmonary complications that are seen in trauma patients. A quantitative method for measuring increased pulmonary capillary permeability that uses Tc-99m HSA allows early diagnosis of acute respiratory distress syndrome (ARDS) and accurately differentiates this condition from pneumonia or cardiogenic pulmonary edema. This technique may be of great value in following the response to therapy. The use of 133Xe to diagnose inhalation injury remains an important diagnostic tool, particularly at hospitals with specialized burn units. Regional decreases in ventilation-perfusion images reliably localize aspirated foreign bodies. Radionuclide techniques that are used to demonstrate gastropulmonary aspiration remain controversial and require further clinical evaluation. Pulmonary perfusion imaging, although nonspecific, may provide the earliest clue for correct diagnosis of fat embolism, air embolism, contusion, or laceration. Furthermore, the possibility of perfusion abnormality due to these uncommon conditions must be remembered whenever trauma patients are evaluated for pulmonary thromboembolism with scintigraphy. Occasionally, liver or spleen scintigraphy may be the most appropriate procedure when penetrating chest trauma also involves these subdiaphragmatic organs.

Radionuclide imaging in the assessment of lung injury.

Nuclear medicine imaging techniques are being more widely applied to study a variety of lung injuries. Ventilation and perfusion imaging is often superior to other roentgenographic techniques for establishing the diagnosis and demonstrating the extent of such injuries. At several large burn centers, the Xe-133 washout technique has become the cornerstone for diagnosing early inhalation injury. The overall accuracy of this procedure is 92%. Regional decreases in ventilation and perfusion can reliably localize aspirated radiolucent foreign bodies. Disproportionate perfusion changes are often the earliest indicator of radiation pneumonitis and other forms of vascular injury. Other types of injury, such as gastropulmonary aspiration, blunt trauma, and near-drowning, require further evaluation before the ultimate role of nuclear imaging is defined. An imaging technique to assess capillary permeability in the adult respiratory distress syndrome would be of great clinical benefits.