- Case report
- Open Access
Point-of-care ultrasound detection of tracheal wall thickening caused by smoke inhalation
© Kameda and Fujita; licensee Springer. 2014
Received: 15 February 2014
Accepted: 1 July 2014
Published: 9 July 2014
Smoke inhalation is the leading cause of death due to fires. When a patient presents with smoke inhalation, prompt assessment of the airway and breathing is necessary. Point-of-care ultrasonography (US) is used for the rapid assessment of critically ill or injured patients. We herein present a case report of a 54-year-old male who was transferred to the emergency department with shortness of breath, coughing, carbonaceous sputa, and rhinorrhea after inhaling smoke caused by a fire in his locked bedroom. He had no surface burns on the face and no edema or erosion in the oral cavity. He had hoarseness without stridor. His breath sounds were positive for expiratory wheezes. Laryngoscopy showed light edema and erosive findings on the supraglottic region. Bedside point-of-care US revealed hypoechoic thickening of the tracheal wall. The thickening was confirmed by a computed tomographic scan. The patient was carefully monitored with preparation for emergency airway management and was treated with supplemental oxygen and an aerosolized beta-2 adrenergic agonist in the intensive care unit. The symptoms were subsequently relieved, and reexamination by US after 2 days showed remission of the wall thickening. Point-of-care US may therefore be a useful modality for the rapid diagnosis and effective follow-up of tracheal wall thickening caused by smoke inhalation.
Smoke inhalation is the leading cause of death due to fires . When a patient presents with smoke inhalation, prompt assessment of the airway and breathing is necessary. Point-of-care ultrasonography (US) is used for the rapid diagnostic assessment and the procedural guidance of critically ill or injured patients . It is easily repeatable; therefore, it is an ideal imaging modality for close observation of such patients . Point-of-care US is now being used for airway assessment and management in the emergency, critical care, and anesthetic settings [3, 4]. However, to the best of our knowledge, the use of US for the detection of tracheal wall thickening caused by smoke inhalation has never been reported in the English literature. We herein present a case report of a patient presenting with smoke inhalation whose tracheal wall thickness was evaluated repeatedly with point-of-care US.
A 54-year-old male was transferred to the emergency department with shortness of breath, coughing, carbonaceous sputa, and rhinorrhea after inhaling smoke caused by a fire. Approximately 6 h before arrival, he was caught in a fire which started on the ground floor of his house while he was sleeping upstairs in a locked bedroom. He inhaled considerable smoke without direct exposure to the flames. When he was rescued from the site, he was unaware of these symptoms. The symptoms became increasingly evident. He had a past medical history of ischemic stroke without long-term neurological sequelae.
Smoke inhalation injury should be strongly suspected in the presence of a specific history and physical examination [5, 6] and is commonly confirmed by endoscopic examination [5–8]. Fiberoptic bronchoscopy is considered the gold standard for the visualization and evaluation of smoke inhalation injury . However, it may not be readily available around the clock in some institutions. Moreover, it may be uncomfortable for some patients and requires careful anesthesia to avoid airway issues. On the other hand, fiberoptic laryngoscopy is better tolerated by patients and is often more readily available than bronchoscopy in emergency settings. Muehlberger et al. described the efficacy of fiberoptic laryngoscopy for predicting the airway integrity in patients with a possibility of less severe smoke inhalation injuries .
US can allow the identification of tracheal stenosis from various causes . In the present case without facial and neck burns, the anterior wall thickening of the upper trachea was quickly detected with point-of-care US immediately after laryngoscopic evaluation. The tracheal wall consists of the tunica adventitia, tracheal cartilage, and mucosa containing the tracheal glands . In normal volunteers, hypoechoic cartilaginous rings and a hyperechoic air-mucosa interface are detectable on US [3, 9, 11]. Shih et al. reported anterior tracheal wall thicknesses on US of 1.5 ± 0.2 mm and 1.2 ± 0.2 mm in normal male and female volunteers, respectively. In that study, the thickness was defined as the distance from the inner border of the thyroid isthmus to the outer edge of the hyperechoic air-mucosa interface on a transverse section . We measured the thickness of the anterior wall at the level cranially adjacent to the thyroid isthmus that appeared to be the thickest section. Surprisingly, the tracheal wall thickness reached 9.0 mm on admission. The degree of thickening, which is thought to be primarily induced by mucosal edema [12, 13], decreased after 2 days, although it did not normalize. Point-of-care US may be the first modality of choice for the initial evaluation of the upper trachea in patients who suffer smoke inhalation. This noninvasive method may also be useful for repeated evaluation of the proximal airway in conjunction with fiberoptic laryngoscopy in patients with less severe smoke inhalation injuries.
Recently, several papers on laryngeal US have been published on other pathologies [14, 15]. Although we did not observe the laryngeal region with US in this case, we think that, based on these papers, laryngeal US may also be useful to detect any additional pathological changes caused by smoke inhalation.
The tracheal wall thickening detected with US was confirmed with a CT scan in this case. Although it has been shown that chest CT scans can precisely detect the extent of complications such as acute respiratory distress syndrome and pneumonia in patients with smoke inhalation [16, 17], the detection of the tracheal wall thickening caused by smoke inhalation with a CT scan had also never been reported previously. There was one report on the relationship between the bronchial wall thickness detected with a CT scan to the total number of ventilator days, the ICU stay, and the development of pneumonia . We think that further studies are warranted to determine whether the tracheal wall thickness measured with US or CT scans can be used as an early predictor of severity and complications. However, our patient with significant tracheal wall thickening recovered without any complications and did not require tracheal intubation.
Point-of-care US may be a useful modality for the rapid diagnosis and follow-up of tracheal wall thickening caused by smoke inhalation.
Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.
- Miller K, Chang A: Acute inhalation injury. Emerg Med Clin Am 2003, 21: 533–557.View ArticleGoogle Scholar
- Moore CL, Copel JA: Point-of-care ultrasonography. NEJM 2011, 364: 749–757. doi:10.1056/NEJMra0909487View ArticlePubMedGoogle Scholar
- Kristensen MS: Ultrasonography in the management of the airway. Acta Anaesthesiol Scand 2011, 55: 1155–1173. doi:10.1111/j.1399–6576.2011.02518.xView ArticlePubMedGoogle Scholar
- Adi O, Chuan TW, Rishya M: A feasibility study on bedside upper airway ultrasonography compared to waveform capnography for verifying endotracheal tube location after intubation. Crit Ultrasound J 2013, 5: 7. doi:10.1186/2036–7902–5-7PubMed CentralView ArticlePubMedGoogle Scholar
- American Burn Association: Inhalation injury: diagnosis. J Am Coll Surg 2003, 196: 307–312.Google Scholar
- Woodson LC: Diagnosis and grading of inhalation injury. J Burn Care Res 2009, 30: 143–145. doi:10.1097/BCR.0b013e3181923b71View ArticlePubMedGoogle Scholar
- Muehlberger T, Kunar D, Munster A, Couch M: Efficacy of fiberoptic laryngoscopy in the diagnosis of inhalation injuries. Arch Otolaryngol Head Neck Surg 1998, 124: 1003–1007.View ArticlePubMedGoogle Scholar
- Madnani DD, Steele NP, de Vries E: Factors that predict the need for intubation in patients with smoke inhalation injury. Ear Nose Throat J 2006, 85: 278–280.PubMedGoogle Scholar
- Shih JY, Lee LN, Wu HD, Yu CJ, Wang HC, Chang YL, Yang PC: Sonographic imaging of the trachea. J Ultrasound Med 1997, 16: 783–790.PubMedGoogle Scholar
- Brand-Saberi BE, Schäfer T: Trachea: anatomy and physiology. Thorac Surg Clin 2014, 24: 1–5. doi:10.1016/j.thorsurg.2013.09.004View ArticlePubMedGoogle Scholar
- Singh M, Chin KJ, Chan VW, Wong DT, Prasad GA, Yu E: Use of sonography for airway assessment: an observational study. J Ultrasound Med 2010, 29: 79–85.PubMedGoogle Scholar
- Masanès MJ, Legendre C, Lioret N, Saizy R, Lebeau B: Using bronchoscopy and biopsy to diagnose early inhalation injury. Macroscopic and histologic findings. Chest 1995, 107: 1365–1369.View ArticlePubMedGoogle Scholar
- Arakawa A, Fukamizu H, Hashizume I, Kasamatsu N, Nagayoshi M, Shinozuka N, Yasuda T, Ozawa T: Macroscopic and histological findings in the healing process of inhalation injury. Burns 2007, 33: 855–859.View ArticlePubMedGoogle Scholar
- Ding LW, Wang HC, Wu HD, Chang CJ, Yang PC: Laryngeal ultrasound: a useful method in predicting post-extubation stridor. A pilot study. Eur Respir J 2006, 27: 384–389.View ArticlePubMedGoogle Scholar
- Ko DR, Chung YE, Park I, Lee HJ, Park JW, You JS, Chung TN, Park YS, Chung SP, Kim S: Use of bedside sonography for diagnosing acute epiglottitis in the emergency department: a preliminary study. J Ultrasound Med 2012, 31: 19–22.PubMedGoogle Scholar
- Oh JS, Chung KK, Allen A, Batchinsky AI, Huzar T, King BT, Wolf SE, Sjulin T, Cancio LC: Admission chest CT complements fiberoptic bronchoscopy in prediction of adverse outcomes in thermally injured patients. J Burn Care Res 2012, 33: 532–538. doi:10.1097/BCR.0b013e318237455fView ArticlePubMedGoogle Scholar
- Yamamura H, Kaga S, Kaneda K, Mizobata Y: Chest computed tomography performed on admission helps predict the severity of smoke-inhalation injury. Crit Care 2013, 17: R95.PubMed CentralView ArticlePubMedGoogle Scholar
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.