Death at Depth
Burkhard Madea in Asphyxiation, Suffocation,and Neck Pressure Deaths, 2020
In a broad sense, barotrauma is a medical condition of the human body effected through a change of pressure and the concomitant (either reductive or expansive) volumetric changes of gas-filled cavities of the body. In a narrower sense (and for the following text), the term ‘barotraumata’ will be used to depict hyperbaric barotraumata under water. Occurrence of damage is crucially dependent on the pace of pressure changes. In contrast to inanimate objects with elastic material properties (e.g. a balloon), the human body (and its gas-filled cavities) disposes of compensatory mechanisms such as anatomic interconnections of gas-filled cavities to the respiratory tract (e.g. paranasal sinuses, middle ear) and is thus capable of at least some pressure change compensation via breathability of its lungs, if changes occur with modest pace. Accordingly, barotraumata are usually the result of rapid changes between pressure levels (e.g. rapid ascent due to ignorance concerning diving technique or to emergencies), or they occur as the result of pathological changes of involved anatomical structures precluding pressure equalization, such as occlusion of the Eustachian tube or carious cavity formation in teeth.
Sudden Sensorineural Hearing Loss
James R. Tysome, Rahul G. Kanegaonkar in Hearing, 2015
The pressure in the gas-filled space of the middle ear is regulated by the Eustachian tube. If the outer ear pressure changes rapidly and the middle ear does not ‘equalize’, then a mechanical pressure occurs across the eardrum due to the differential air pressure. This can be great enough to cause barotrauma to the ear. Barotrauma most commonly occurs when flying or diving. The greatest pressure change is in the first 10 metres of water submersion or the first 1,000 metres of air ascent, and if equalization does not occur, significant pressure can be generated across the TM. This more commonly causes middle ear changes such as bleeding or effusion, but if the pressure difference is marked between the middle ear and the cerebrospinal fluid/perilymph, a perilymph leak and SSNHL is possible.
Diagnostic Imaging in Inhalation Lung Injury
Jacob Loke in Pathophysiology and Treatment of Inhalation Injuries, 2020
During the first 24 hr following the acute event, complications related totherapeutic intervention may also be apparent on chest radiographs. The placement and optimal positioning of central venous lines and endotracheal and nasogastric tubes can be monitored on chest radiographs. The rapid appearance of pleural or mediastinal fluid after venous line placement should raise the possibility of arterial injury or aberrant line placement with subsequent infusion of fluid (Fig. 4). Positioning of the endotracheal tube in a mainstem bronchus can result in collapse of the opposite lung, a potentially life-threatening complication in apatient with pre-existing lung injury. In addition, barotrauma related to mechanical ventilation may first be detected by chest radiographs (Fig. 3a). Chest radiographs in critically ill patients are often obtained using a portable unit with the patient supine. Attention should be directed to the highest portions of the thorax, the anterior costophrenic sulci in the supine patient, when pneumothorax is suspected.
Barotrauma after liquid nitrogen ingestion: a case report and literature review
Published in Postgraduate Medicine, 2018
Yuemei Zheng, Xiaoxia Yang, Xinli Ni
Liquid nitrogen is not commonly used in food and drink, but if ingested it can lead to digestive tract injury. When encountering a patient who has swallowed liquid nitrogen, frostbite is often considered the main cause of the injury. This is because liquid nitrogen boils at −196°C and may cause frostbite on contact. Barotrauma was finally recognized the main injury mechanism in such cases after a retrospective analysis and literature review. The unique properties of liquid nitrogen produce a characteristic injury pattern. That is, liquid nitrogen gasification will increase the stomach volume by 700 times followed by a rapid increase in intraluminal pressure, leading to severe pneumoperitoneum or gastric rupture. Gastric perforation always occurs along the lesser curvature, where the stomach is relatively fixed to adjacent structures. Damage to the respiratory system is not common.
Low tidal volume ventilation alleviates ventilator-induced lung injury by regulating the NLRP3 inflammasome
Published in Experimental Lung Research, 2022
Lixia Wang, Jun Li, Yan Zhu, Binshan Zha
Alveolar barotrauma is a major mechanism underlying VILI.23 Excessive tidal volume is the main cause of barotrauma.24 In our study, high-tidal-volume ventilation (Vt = 10 mL/kg IBW) was chosen during one lung ventilation in patients. Correspondingly, we found that high-tidal-volume ventilation during OLV increased Ppeak, Pplat, and ΔP significantly. However, LTTV (Vt = 5 mL/kg and 5 cm of H2O PEEP) decreased Ppeak, Pplat, and ΔP notably during OLV, indicating that alveolar overdistention was avoided and barotrauma may be reduced. In addition, we also found that LTTV increased Paw during OLV. Paw could be used to safeguard oxygenation when titrating ventilation, because Paw and oxygenation demonstrate a predictable and quantifiable direct relationship.25 Here, our present study found that oxygenation index in patients of LTTV group showed an increasing trend, although there was no significant difference compared with the control group. Therefore, our results suggested that LTTV may exert its lung protective capacity mainly by reducing alveolar barotrauma.
Firefighters during training as divers: physiologic and psychomental stresses
Published in International Journal of Occupational Safety and Ergonomics, 2022
Thomas Muth, Ingo Hansen, Clark Pepper, Jochen D Schipke
An easy 20-min scuba dive at a depth of only 10 m was already perceived to be stressful because the cortisol level after the dive was significantly increased [27]. Many stressors are responsible: after submersion, the hydrostatic pressure increases and compresses the gas-filled spaces outside and inside the diver’s body, causing barotrauma if not adequately responded to [28]. Other stressors possibly arising are impaired visibility, time pressure while searching, strenuous work and complex tasks. Finally, cold needs mentioning, because it impairs underwater performance [29], in particular for higher-order tasks [30]. Apart from these stressors, additional psychological stress was present, because the participants of this study were in demanding training situations with evaluations and group pressure.
