Terboven et al. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine (2019) 27:45 https://doi.org/10.1186/s13049-019-0623-5 ORIGINALRESEARCH Open Access Chest wall thickness and depth to vital structures in paediatric patients – implications for prehospital needle decompression of tension pneumothorax Tom Terboven1* , Georg Leonhard1, Lucas Wessel2, Tim Viergutz1, Marcus Rudolph1,3, Michael Schöler1, Meike Weis4 and Holger Haubenreisser4 Abstract Background: Recommendations regarding decompression of tension pneumothorax in small children are scarce and mainly transferred from the adult literature without existing evidence for the paediatric population. This CT- based study evaluates chest wall thickness, width of the intercostal space (ICS) and risk of injury to vital structures by needle decompression in children. Methods: Chest wall thickness, width of the intercostal space and depth to vital structures were measured and evaluated at 2nd ICS midclavicular (MCL) line and 4th ICS anterior axillary line (AAL) on both sides of the thorax using computed tomography (CT) in 139 children in three different age groups (0, 5, 10 years). Results: Width of the intercostal space was significantly smaller at the 4th ICS compared to the 2nd ICS in all age groups on both sides of the thorax. Chest wall thickness was marginally smaller at the 4th ICS compared to the 2nd ICS in infants and significantly smaller at 4th ICS in children aged 5 years and 10 years. Depth to vital structure for correct angle of needle entry was smaller at the 4th ICS in all age groups on both sides of the thorax. Incorrect angle of needle entry however is accompanied by a higher risk of injury at 2nd ICS. Furthermore, in some children aged 0 and 5 years, the heart or the thymus gland were found directly adjacent to the thoracic wall at 2nd ICS midclavicular line. Conclusion: Especially in small children risk of iatrogenic injury to vital structures by needle decompression is considerably high. The 4th ICS AAL offers a smaller chest wall thickness, but the width of the ICS is smaller and the risk of injury to the intercostal vessels and nerve is greater. Deviations from correct angle of entry however are accompanied by higher risk of injury to intrathoracic structures at the 2nd ICS. Furthermore, we found the heart and the thymus gland to be directly adjacent to the thoracic wall at the 2nd ICS MCL in a few children. From our point of view this puncture site can therefore not be recommended for decompression in small children. We therefore recommend 4th ICS AAL as the primary site of choice. Keywords: Tension pneumothorax, Needle decompression, Children, Paediatric, Chest wall thickness, Complications * Correspondence: [email protected] 1Department of Anaesthesiology and Intensive Care Medicine, University Medical Center Mannheim, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany Full list of author information is available at the end of the article © The Author(s). 2019 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Terboven et al. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine (2019) 27:45 Page 2 of 10 Background Therefore, the primary aim of this study was evalu- Traumatic or spontaneous tension pneumothorax is a po- ation of the insertion site recommended by APLS guide- tentially fatal event that requires immediate decompres- lines (2nd ICS MCL) regarding risk of injury to sion. Currently recommended interventions for intrathoracic vital structures. Secondary aims were asses- decompression are either needle thoracostomy or open sing required insertion depth of the needle for successful finger thoracostomy [1, 2]. Needle thoracostomy is gener- decompression and measuring width of the intercostal ally easier to learn, faster to perform and less invasive than space to study if finger thoracostomy is possible. Fur- surgical decompression. It therefore represents the pre- thermore, we investigated the same questions at the 4th ferred first line technique for many emergency providers ICS AAL as an alternative insertion site. and is recommended in several trauma guidelines [2, 3]. However, recent ATLS 10th edition guidelines suggest Methods 4th/5th ICS mid-axillary line as preferable to 2nd ICS in Inclusion criteria were meeting one of the required age adults and recommends same management for pneumo- groups and availability of a thoracic CT scan in the local thorax in children, except for needle or tube size. 2nd ICS picture communication and archiving system. A total of MCL is still recommended as a possible insertion site in 197 paediatric patients referred for thoracic CT with vari- children [4]. There is no reference in the APLS 6th edition ous indications were initially included in this study. We ex- on depth of insertion and it recommends 2nd ICS inser- cluded all patients with a condition that made one or more tion site only [5]. Commonly recommended puncture of the measurements impossible or inaccurate. Conse- techniques are insertion sagittal to the chest wall at the quently 58 patients were excluded due to various pulmon- 2nd intercostal space (ICS) in the midclavicular line ary pathologies which made the required measurements (MCL) and perpendicular to the chest wall at the 4th or impossible or invalid. Most of the excluded patients were 5th ICS anterior axillary line (AAL) or midaxillary line infants with large intrathoracic pathologies or conditions (MAL). However, failed decompression is a commonly re- resulting in mediastinal shift. Details on reasons for exclu- ported phenomenon in needle thoracostomy [6]. There- sion are shown in Table 1. The remaining 139 patients were fore, in recent years, several studies examining chest wall included in three study groups aged 0, 5 and 10 years. thickness (CWT) at the recommended insertion sites have been conducted in adult patients and found commonly Data acquisition used cannulas being too short for successful decompres- All patients had paediatric thoracic CT protocol (2nd sion in a high proportion of patients [6]. This has led to generation DSCT, Siemens Somatom Definition Flash, the recommendation of using longer 7-8 cm catheters for Siemens Healthineers, Forchheim, Germany) or 16 slice needle thoracostomy in adult patients [7–9]. Even though MSCT (Siemens Emotion 16, Siemens Healthineers, For- this increases the likelihood of successful decompression, chheim, Germany). All examinations were reconstructed it also increases the risk of injuring underlying vital struc- with 1.5 mm slice thickness, increments of 1.0 mm, a tures like large intrathoracic vessels or the heart because dedicated lung reconstruction kernel (I70s (DSCT) or of the possibility of deeper insertion [9]. Due to the B70s (MSCT)) and soft tissue reconstruction kernel smaller anatomic structures, tension pneumothorax repre- (I30s (DSCT) or B30s (MSCT)). The reconstruction ker- sents a particular challenge in paediatric patients. Open nels on the DSCT system utilized an iterative recon- finger thoracostomy in the very narrow intercostal spaces struction algorithm with a strength level of 2. Image in children requires smaller instruments and some surgi- data were imported into a PACS Workstation (Aycan cal skills, which are often not available in the prehospital OsiriX PRO v.2.10, Aycan Digitalsysteme GmbH, Würz- setting. Especially in small children it is accompanied by burg, Germany) and evaluated in an axial plane, as well the risk of too large incisions with leakage of air along as using multiplanar reconstructions (MPR). We used chest tubes. Furthermore, whilst the technique is similar the orthogonal MPR feature in our DICOM viewer to an adult, invasive paediatric critical procedures are (Osirix). This allows for accurate measurements in all often associated with cognitive hurdles and dissonance. planes, as the data are built from 1.5 mm slices with 1.0 Little is known about the required insertion depth of a mm increment. The overlapping datasets ensure that the needle for decompression in paediatrics or the likelihood MPR images are true to the original, with no drawbacks of injuring underlying vital structures. Because of the nar- compared to axial/coronal/sagittal reconstructions from row intercostal space, the risk of injury to the intercostal the scanner. All CTs were reviewed and measurements vessels and nerves has to be taken into consideration recorded by one specialist in paediatric radiology. when performing needle decompression. We aimed to evaluate the required depth for successful decompression, Measurements defined as the distance from skin to pleural space, whilst Measurements were made at 2nd ICS MCL and 4th ICS minimizing iatrogenic underlying structure injury. AAL on both sides of the thorax. ICS width was Terboven et al. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine (2019) 27:45 Page 3 of 10 Table 1 Reasons for exclusion Reason for exclusion n (0 years) n (5 years) n (10 years) n (total) Mediastinal shift 12 1 1 14 Pulmonary infiltration 11 1 0 12 CPAM 8 0 0 8 Pulmonary bullae 6 0 0 6 Pleural effusion/empyema 3 2 0 5 Poor image quality 1 3 0 4 Spinal misalignment 1 1 1 3 Emphysema 3 0 0 3 Congenital diaphragmatic hernia 2 0 0 2 Intrathoracic mass 1 0 0 1 Total 48 8 2 58 measured from the inferior border of the superior rib to wall thickness was measured from the skin surface to the superior edge of the inferior rib. Chest wall thickness the pleural cavity. Depth to vital structure was de- and the depth to the closest vital structure were mea- fined as the distance from the skin surface to the sured in various directions: in the sagittal plane at the intersection with a vital structure.