Tension pneumothorax

Occult tension pneumothorax discovered following imaging for adult trauma patients in the modern major trauma system: a multicentre observational study

BACKGROUND

Tension pneumothorax following trauma is a life-threatening emergency and radiological investigation is normally discouraged prior to treatment in traditional trauma doctrines such as ATLS. Some trauma patients may be physiologically stable enough for diagnostic imaging and occult tension pneumothorax is discovered radiologically. We assessed the outcomes of these patients and compared them with those with clinical diagnosis of tension pneumothorax prior to imaging.

METHODS

A multicentre civilian-military collaborative network of six major trauma centres in the UK collected observational data from adult patients who had a diagnosis of traumatic tension pneumothorax during a 33-month period. Patients were divided into 'radiological' (diagnosis following CT/CXR) or 'clinical' (no prior CT/CXR) groups. The effect of radiological diagnosis on survival was analysed using multivariable logistic regression that included the covariates of age, gender, comorbidities and Injury Severity Score.

RESULTS

There were 133 patients, with a median age of 41 (IQR 24-61); 108 (81%) were male. Survivors included 49 of 59 (83%) in the radiological group and 59 of 74 (80%) in the clinical group (p=0.487). Multivariable logistic regression showed no significant association between radiological diagnosis and survival (OR 2.40, 95% CI 0.80 to 7.95; p=0.130). There was no significant difference in mortality between the groups.

CONCLUSION

Radiological imaging may be appropriate for selected trauma patients at risk of tension pneumothorax if they are considered haemodynamically stable. Trauma patients may be physiologically stable enough for radiological imaging but have occult tension pneumothorax because they did not have the typical clinical presentation. The historical dogma of the 'forbidden scan' no longer applies to such patients.

Prehospital management of chest injuries in severely injured patients-a systematic review and clinical practice guideline update

PURPOSE

Our aim was to review and update the existing evidence-based and consensus-based recommendations for the management of chest injuries in patients with multiple and/or severe injuries in the prehospital setting. This guideline topic is part of the 2022 update of the German Guideline on the Treatment of Patients with Multiple and/or Severe Injuries.

METHODS

MEDLINE and Embase were systematically searched to May 2021. Further literature reports were obtained from clinical experts. Randomised controlled trials, prospective cohort studies, cross-sectional studies, and comparative registry studies were included if they compared interventions for the detection and management of chest injuries in severely injured patients in the prehospital setting. We considered patient-relevant clinical outcomes such as mortality and diagnostic test accuracy. Risk of bias was assessed using NICE 2012 checklists. The evidence was synthesised narratively, and expert consensus was used to develop recommendations and determine their strength.

RESULTS

Two new studies were identified, both investigating the accuracy of in-flight ultrasound in the detection of pneumothorax. Two new recommendations were developed, one recommendation was modified. One of the two new recommendations and the modified recommendation address the use of ultrasound for detecting traumatic pneumothorax. One new good (clinical) practice point (GPP) recommends the use of an appropriate vented dressing in the management of open pneumothorax. Eleven recommendations were confirmed as unchanged because no new high-level evidence was found to support a change.

CONCLUSION

Some evidence suggests that ultrasound should be considered to identify pneumothorax in the prehospital setting. Otherwise, the recommendations from 2016 remained unchanged.

Recurrent Spontaneous Pneumothorax Secondary to Marijuana and Tobacco Abuse

Primary spontaneous pneumothorax occurs in patients without apparent clinical lung disease, with a higher incidence in tall, thin males between the ages of 10 and 30. Tension pneumothorax is a life-threatening condition that can develop within minutes due to progressive air accumulation in the pleural space; mechanical pressure can lead to significant cardiorespiratory compromise. Tobacco association with a higher incidence of spontaneous pneumothorax has been well documented, but marijuana and spontaneous pneumothorax connection has not been well studied. However, it has been observed that patients who use marijuana and tobacco simultaneously have a higher incidence of spontaneous tension and larger pneumothoraces, as well as longer postoperative stay and higher recurrence than cigarette-only users. We present a case of a 26-year-old young male with a history only significant for excessive tobacco and marijuana smoking who developed multiple recurrent spontaneous pneumothorax and had to undergo right-sided video-assisted thoracoscopic surgery (VATS) with minimally invasive thoracotomy and had a prolonged hospital stay. With our case report, we hope to add to the evidence the effects of combined marijuana and tobacco smoking on bullous lung disease and pneumothorax while emphasizing the importance of conducting a detailed substance use history in patients with spontaneous pneumothorax.

SPLF/SMFU/SRLF/SFAR/SFCTCV Guidelines for the management of patients with primary spontaneous pneumothorax

INTRODUCTION

Primary spontaneous pneumothorax (PSP) is the presence of air in the pleural space, occurring in the absence of trauma and known lung disease. Standardized expert guidelines on PSP are needed due to the variety of diagnostic methods, therapeutic strategies and medical and surgical disciplines involved in its management.

METHODS

Literature review, analysis of the literature according to the GRADE (Grading of Recommendation, Assessment, Development and Evaluation) methodology; proposals for guidelines rated by experts, patients and organizers to reach a consensus. Only expert opinions with strong agreement were selected.

RESULTS

A large PSP is defined as presence of a visible rim along the entire axillary line between the lung margin and the chest wall and ≥ 2 cm at the hilum level on frontal chest X-ray. The therapeutic strategy depends on the clinical presentation: emergency needle aspiration for tension PSP; in the absence of signs of severity: conservative management (small PSP), needle aspiration or chest tube drainage (large PSP). Outpatient treatment is possible if a dedicated outpatient care system is previously organized. Indications, surgical procedures and perioperative analgesia are detailed. Associated measures, including smoking cessation, are described.

CONCLUSION

These guidelines are a step towards PSP treatment and follow-up strategy optimization in France.

SPLF/SMFU/SRLF/SFAR/SFCTCV Guidelines for the management of patients with primary spontaneous pneumothorax: Endorsed by the French Speaking Society of Respiratory Diseases (SPLF), the French Society of Emergency Medicine (SFMU), the French Intensive Care Society (SRLF), the French Society of Anesthesia & Intensive Care Medicine (SFAR) and the French Society of Thoracic and Cardiovascular Surgery (SFCTCV)

INTRODUCTION

Primary spontaneous pneumothorax (PSP) is the presence of air in the pleural space, occurring in the absence of trauma and known lung disease. Standardized expert guidelines on PSP are needed due to the variety of diagnostic methods, therapeutic strategies and medical and surgical disciplines involved in its management.

METHODS

Literature review, analysis of literature according to the GRADE (Grading of Recommendation Assessment, Development and Evaluation) methodology; proposals for guidelines rated by experts, patients, and organizers to reach a consensus. Only expert opinions with strong agreement were selected.

RESULTS

A large PSP is defined as presence of a visible rim along the entire axillary line between the lung margin and the chest wall and ≥2 cm at the hilum level on frontal chest x-ray. The therapeutic strategy depends on the clinical presentation: emergency needle aspiration for tension PSP; in the absence of signs of severity: conservative management (small PSP), needle aspiration or chest tube drainage (large PSP). Outpatient treatment is possible if a dedicated outpatient care system is previously organized. Indications, surgical procedures and perioperative analgesia are detailed. Associated measures, including smoking cessation, are described.

CONCLUSION

These guidelines are a step towards PSP treatment and follow-up strategy optimization in France.

Recommandations formalisées d’experts pour la prise en charge des pneumothorax spontanés primaires

Introduction : Le pneumothorax spontané primaire (PSP) est un épanchement gazeux dans la cavité pleurale, survenant hors traumatisme et pathologie respiratoire connue. Des recommandations formalisées d'experts sur le sujet sont justifiées par les pluralités de moyens diagnostiques, stratégies thérapeutiques et disciplines médicochirurgicales intervenant dans leur prise en charge.

Méthodes : Revue bibliographique, analyse de la littérature selon méthodologie GRADE (Grading of Recommendation Assessment, Development and Evaluation) ; propositions de recommandations cotées par experts, patients et organisateurs pour obtenir un consensus. Seuls les avis d'experts avec accord fort ont été retenus.

Résultats : Un décollement sur toute la hauteur de la ligne axillaire et supérieur ou égal à 2 cm au niveau du hile à la radiographie thoracique de face définit la grande abondance. La stratégie thérapeutique dépend de la présentation clinique : exsufflation en urgence pour PSP suffocant ; en l'absence de signe de gravité : prise en charge conservatrice (faible abondance), exsufflation ou drainage (grande abondance). Le traitement ambulatoire est possible si organisation en amont de la filière. Les indications, procédures chirurgicales et l'analgésie périopératoire sont détaillées. Les mesures associées, notamment le sevrage tabagique, sont décrites.

Conclusion : Ces recommandations sont une étape de l'optimisation des stratégies de traitement et de suivi des PSP en France.

Pneumothorax in patients with respiratory failure in ICU

Pneumothorax is not an uncommon occurrence in ICU patients. Barotrauma and iatrogenesis remain the most common causes for pneumothorax in critically ill patients. Patients with underlying lung disease are more prone to develop pneumothorax, especially if they require positive pressure ventilation. A timely diagnosis of pneumothorax is critical as it may evolve into tension physiology. Most occurrences of pneumothoraces are readily diagnosed with a chest X-ray. Tension pneumothorax is a medical emergency, and managed with immediate needle decompression followed by tube thoracostomy. A computed tomography (CT) scan of the chest remains the gold standard for diagnosis; however, getting a CT scan of the chest in a critically ill patient can be challenging. The use of thoracic ultrasound has been emerging and is proven to be superior to chest X-ray in making a diagnosis. The possibility of occult pneumothorax in patients with thoracoabdominal blunt trauma should be kept in mind. Patients with pneumothorax in the ICU should be managed with a tube thoracostomy if they are symptomatic or on mechanical ventilation. The current guidelines recommend a small-bore chest tube as the first line management of pneumothorax. In patients with persistent air leak or whose lungs do not re-expand, a thoracic surgery consultation is recommended. In non-surgical candidates, bronchoscopic interventions or autologous blood patch are other options.

Treatment of Pneumothorax as a Complication of Long-Term Central Venous Port Placement in Oncology Patients. An Observational Study

Background and Purpose

In percutaneous placement of central venous catheters an inadvertent, direct lesion of the lung parenchyma can occur. This is a cause of iatrogenic pneumothorax, whose incidence is approximately 1 to 4%, largely dependent on the experience of the operator, the site of venipuncture and probably the technique employed. Initial treatment currently ranges from observation alone to formal tube-thoracostomy. In an attempt to define the best initial treatment, if any, we reviewed our personal series and contributions from the literature. As a result we have produced a flow-chart proposing a rational treatment of this frequent complication.

Patients and Methods

One thousand four hundred twenty-one ports were placed in patients at the Department of Surgery of the European Institute of Oncology in Milan through an infraclavicular standardized percutaneous subclavian approach. They were placed during the 60-month period from January 1, 1996 to December 31, 2000 for long-term chemotherapy treatment of solid tumours. Chest upright X-rays were obtained post-operatively in all cases to check the correct position of the catheter tip and the presence of pneumothorax.

Results

Twenty-two patients out of 1421 (1.54%) experienced a radiologically-proven pneumothorax, ranging from 5 to 70% of the affected pleural space. Sixteen patients out of 22 (72.7%) with minor portions of affected pleural space received simple observation. In these patients the most common finding was an uncomplicated tachycardia (more than 100 beats/min); 8 of them did not complain of any symptoms. Six patients (27.2%) underwent an additional procedure (3 tube-thoracostomies and 3 aspirations of the pleural space), claiming symptoms of chest pain and various degrees of dyspnea. Tube thoracostomy was mainly adopted at the beginning of our experience, and in patients with a severe degree of pleural involvement (55 to 70% of the pleural space). Aspiration, instead, was used more recently and in patients with varying degrees of pleural space involved, ranging from 40 to 60%.

Conclusions

Looking at our own series and literature data, patients with iatrogenic pneumothorax following central venous cannulation who do not have a severe underlying pulmonary disease can be reassured, at the time of diagnosis, that surgery is usually unnecessary and tube thoracostomy is rarely needed. Simple aspiration of the pleural air by means of a central venous catheter inserted percutaneously into the pleural space under local anesthesia should be considered, even if the amount of affected pleural space is more than 50%, before opting for a formal tube-thoracostomy using small-bore tubes.

Can Tension Haemopneumothorax Have Stable Haemodynamics?

Tension pneumothorax or haemopneumothorax is a clinical diagnosis. Plain radiography is not advised to confirm the diagnosis and may delay definitive treatment. Unstable haemodynamics is one of the prerequisites for the diagnosis. We report a case in which the patient suffered from haemopneumothorax with all the typical radiological features of tension, but without any clinical sign of unstable haemodynamics. Close monitoring of patients suspected to have pneumothorax is recommended, especially in the radiology suite.

[Tension pneumomediastinum and tension pneumothorax following tracheal perforation during cardiopulmonary resuscitation]

Tension pneumothorax can occur at any time during cardiopulmonary resuscitation (CPR) with external cardiac massage and invasive ventilation either from primary or iatrogenic rib fractures with concomitant pleural or parenchymal injury. Airway injury can also cause tension pneumothorax during CPR. This article presents the case of a 41-year-old woman who suffered cardiopulmonary arrest after undergoing elective mandibular surgery. During CPR the upper airway could not be secured by orotracheal intubation due to massive craniofacial soft tissue swelling. A surgical airway was established with obviously unrecognized iatrogenic tracheal perforation and subsequent development of tension pneumomediastinum and tension pneumothorax during ventilation. Neither the tension pneumomediastinum nor the tension pneumothorax were decompressed and accordingly resuscitation efforts remained unsuccessful. This case illustrates the need for a structured approach to resuscitate patients with ventilation problems regarding decompression of tension pneumomediastinum and/or tension pneumothorax during CPR.

Evaluation and treatment of trauma related collapse in athletes

Although blunt traumatic injuries are common in athletes, life-threatening trauma is fortunately rare. Most current literature has focused on nontraumatic causes of athlete death though traumatic injuries may be more common. Although prevention of these injuries may be more difficult than nontraumatic causes, prompt recognition and treatment is paramount. Common traumatic causes of collapse athlete generally involve the head, neck, and trunk and are more frequent in collision sports. Other higher risk sports include track and field, cheerleading, snow sports, and those involving motorized vehicles. Health care providers who participate in sports coverage should be aware of the potential for these injuries as emergency treatment is required to maximize outcomes. Emergency action plans allow providers to expediently activate emergency management services while providing treatment and stabilization.

Evaluation of 8.0-cm needle at the fourth anterior axillary line for needle chest decompression of tension pneumothorax

BACKGROUND

Five-centimeter needles at the second intercostal space midclavicular line (2MCL) have high failure rates for decompression of tension pneumothorax. This study evaluates 8-cm needles directed at the fourth intercostal space anterior axillary line (4AAL).

METHODS

Retrospective radiographic analysis of 100 consecutive trauma patients 18 years or older from January to September 2011. Measurements of chest wall thickness (CWT) and depth to vital structure (DVS) were obtained at 2MCL and 4AAL. 4AAL measurements were taken based on two angles: closest vital structure and perpendicular to the chest wall. Primary outcome measures were radiographic decompression (RD) (defined as CWT < 80 mm) and radiographic noninjury (RNI) (DVS > 80 mm) of 8-cm needles at 4AAL. Secondary outcome measures are effect of angle of entry on RNI at 4AAL, RD and RNI of 8-cm needles at 2MCL, and comparison of 5-cm needles with 8-cm needles at both locations.

RESULTS

Eighty-four percent of the patients were male, with mean Injury Severity Score (ISS) of 17.7 (range, 1.0-66.0) and body mass index of 26.8 (16.5-48.4). Mean CWT at 4AAL ranged from 37.6 mm to 39.9 mm, significantly thinner than mean CWT at 2MCL (43.3-46.7 mm). Eight-centimeter needle RD was more than 96% at both 4AAL and 2MCL. Five-centimeter RD ranged from 66% to 81% at all sites. Mean DVS at 4AAL ranged from 91.8 mm to 128.0 mm. RNI at all sites was more than 91% except at left 4AAL, when taken to the closest vital structure (mean DVS, 91.8 mm), with 68% RNI. Perpendicular entry increased DVS to 109.4 mm and subsequent RNI to 91%. Five-centimeter RNI at all sites was more than 99%.

CONCLUSION

CWT at 4AAL is significantly thinner than 2MCL. Based on radiographic measurements, 8-cm catheters have a higher chance of pleural decompression when compared with 5-cm catheters. Steeper angle of entry at 4AAL improves 8-cm noninjury rates to more than 91%.

LEVEL OF EVIDENCE

Therapeutic/care management study, level IV.

Clinical manifestations of tension pneumothorax: protocol for a systematic review and meta-analysis

BACKGROUND

Although health care providers utilize classically described signs and symptoms to diagnose tension pneumothorax, available literature sources differ in their descriptions of its clinical manifestations. Moreover, while the clinical manifestations of tension pneumothorax have been suggested to differ among subjects of varying respiratory status, it remains unknown if these differences are supported by clinical evidence. Thus, the primary objective of this study is to systematically describe and contrast the clinical manifestations of tension pneumothorax among patients receiving positive pressure ventilation versus those who are breathing unassisted.

METHODS/DESIGN

We will search electronic bibliographic databases (MEDLINE, PubMed, EMBASE, and the Cochrane Database of Systematic Reviews) and clinical trial registries from their first available date as well as personal files, identified review articles, and included article bibliographies. Two investigators will independently screen identified article titles and abstracts and select observational (cohort, case-control, and cross-sectional) studies and case reports and series that report original data on clinical manifestations of tension pneumothorax. These investigators will also independently assess risk of bias and extract data. Identified data on the clinical manifestations of tension pneumothorax will be stratified according to whether adult or pediatric study patients were receiving positive pressure ventilation or were breathing unassisted, as well as whether the two investigators independently agreed that the clinical condition of the study patient(s) aligned with a previously published tension pneumothorax working definition. These data will then be summarized using a formal narrative synthesis alongside a meta-analysis of observational studies and then case reports and series where possible. Pooled or combined estimates of the occurrence rate of clinical manifestations will be calculated using random effects models (for observational studies) and generalized estimating equations adjusted for reported potential confounding factors (for case reports and series).

DISCUSSION

This study will compile the world literature on tension pneumothorax and provide the first systematic description of the clinical manifestations of the disorder according to presenting patient respiratory status. It will also demonstrate a series of methods that may be used to address difficulties likely to be encountered during the conduct of a meta-analysis of data contained in published case reports and series. PROSPERO registration number: CRD42013005826.

Characteristics and mechanisms of cardiopulmonary injury caused by mine blasts in shoals: a randomized controlled study in a rabbit model

Background

Because the characteristics of blast waves in water are different from those in air and because kinetic energy is liberated by a pressure wave at the water-air interface, thoracic injuries from mine blasts in shoals may be serious. The aim of the present study was to investigate the characteristics and mechanisms of cardiopulmonary injury caused by mine blasts in shoals.

Methods

To study the characteristics of cardiopulmonary injury, 56 animals were divided randomly into three experimental groups (12 animals in the sham group, 22 animals in the land group and 22 animals in the shoal group). To examine the biomechanics of injury, 20 animals were divided randomly into the land group and the shoal group. In the experimental model, the water surface was at the level of the rabbit's xiphoid process, and paper electric detonators (600 mg RDX) were used to simulate mines. Electrocardiography and echocardiography were conducted, and arterial blood gases, serum levels of cardiac troponin I and creatine kinase-MB and other physiologic parameters were measured over a 12-hour period after detonation. Pressures in the thorax and abdomen and the acceleration of the thorax were measured.

Conclusion

The results indicate that severe cardiopulmonary injury and dysfunction occur following exposure to mine blasts in shoals. Therefore, the mechanisms of cardiopulmonary injury may result from shear waves that produce strain at the water-air interface. Another mechanism of injury includes the propagation of the shock wave from the planta to the thorax, which causes a much higher peak overpressure in the abdomen than in the thorax; as a result, the abdominal organs and diaphragm are thrust into the thorax, damaging the lungs and heart.

Results of thoracic drainages placed in air rescue

INTRODUCTION

horax injuries are to be found in approximately 78% amongst all accident victims. Moreover, they implicate an increase in mortality rate. Consequently, an adequate contemporary treatment has to begin preclinically, even if the conditions are less comfortable than in a clinical setting. Emergency doctors need to be familiar with the placement of chest tubes.

MATERIALS AND METHODS

From January 1, 2007 to December 31, 2010, emergency doctors of the rescue helicopter site Christoph 20 had to place chest tubes directly at the scene of an accident in 49 patients. These patients were now reidentified, and their clinical course was reevaluated. By means of apparative diagnostics, it was possible to analyze the location of the tubes tip. Following a comparison of the patient, outcome versus the quality of preclinical thoracic discharge could be made.

RESULTS

The preclinical placement of a chest tube became necessary mainly because of a blunt thoracic trauma. This was predominantly related to victims of traffic accidents, whereas male victims clearly dominated. Forty-two of those patients received further treatment at the Klinikum Bayreuth hospital, enabling an analysis of the tubes location by CAT (computed axial tomography) scan. Six patients had been discharged on both sides, contributing to 48 tube tips that could be examined concerning their location. Of the 48 chest tubes, 46 had been placed from a lateral approach. The ventral access by Monaldi had only been chosen in two cases. Altogether, nine incorrect placements, mainly within the right interlobe gap, had been detected.

CONCLUSIONS

The study collective showed a significant preference to the lateral approach when placing a chest tube at the emergency scene of an accident. In total, a prevalence of 19% incorrect placements could be revealed, meaning the chest tube had either been placed within the lung parenchyma, the interlobe gap, or extrathoracically. Concerning the patient outcome, no statistically significant difference regarding the clinical course after incorrect chest tube placement could be identified.

Tension pneumothorax, is it a really life-threatening condition?

BACKGROUND

Tension pneumothorax is a life-threatening occurrence that is infrequently the consequence of spontaneous pneumothorax. The aim of this study was to identify the risk factors for the development of tension pneumothorax and its effect on clinical outcomes.

METHODS

We reviewed patients who were admitted with spontaneous pneumothorax between August 1, 2003 and December 31, 2011. Electronic medical records and the radiological findings were reviewed with chest x-ray and high-resolution computed tomography scans that were retrieved from the Picture Archiving Communication System.

RESULTS

Out of the 370 patients included in this study, tension pneumothorax developed in 60 (16.2%). The bullae were larger in patients with tension pneumothorax than in those without (23.8 ± 16.2 mm vs 16.1 ± 19.1 mm; P = 0.007). In addition, the incidence of tension pneumothorax increased with the lung bulla size. Fibrotic adhesion was more prevalent in the tension pneumothorax group than in that without (P = 0.000). The bullae were large in patients with fibrotic adhesion than in those without adhesion (35.0 ± 22.3 mm vs 10.4 ± 11.5 mm; P = 0.000). On multivariate analysis, the size of bullae (odds ratio (OR) = 1.03, P = 0.001) and fibrotic adhesion (OR = 10.76, P = 0.000) were risk factors of tension pneumothorax. Hospital mortality was 3.3% in the tension pneumothorax group and it was not significantly different from those patients without tension pneunothorax (P = 0.252).

CONCLUSIONS

Tension pneumothorax is not uncommon, but clinically fatal tension pneumothorax is extremely rare. The size of the lung bullae and fibrotic adhesion contributes to the development of tension pneumothorax.

Using thoracic ultrasonography to accurately assess pneumothorax progression during positive pressure ventilation: a comparison with CT scanning

BACKGROUND

Although thoracic ultrasonography accurately determines the size and extent of occult pneumothoraces (PTXs) in spontaneously breathing patients, there is uncertainty about patients receiving positive pressure ventilation. We compared the lung point (ie, the area where the collapsed lung still adheres to the inside of the chest wall) using the two modalities ultrasonography and CT scanning to determine whether ultrasonography can be used reliably to assess PTX progression in a positive-pressure-ventilated porcine model.

METHODS

Air was introduced in incremental steps into fi ve hemithoraces in three intubated porcine models. The lung point was identified on ultrasound imaging and referenced against the lateral limit of the intrapleural air space identified on the CT scans. The distance from the sternum to the lung point (S-LP) was measured on the CT scans and correlated to the insufflated air volume.

RESULTS

The mean total difference between the 131 ultrasound and CT scan lung points was 6.8 mm (SD, 7.1 mm; range, 0.0-29.3 mm). A mixed-model regression analysis showed a linear relationship between the S-LP distances and the PTX volume ( P , .001).

CONCLUSIONS

In an experimental porcine model, we found a linear relation between the PTX size and the lateral position of the lung point. The accuracy of thoracic ultrasonography for identifying the lung point (and, thus, the PTX extent) was comparable to that of CT imaging. These clinically relevant results suggest that ultrasonography may be safe and accurate in monitoring PTX progression during positive pressure ventilation.

The intrapleural volume threshold for ultrasound detection of pneumothoraces: an experimental study on porcine models

Background

Small pneumothoraxes (PTXs) may not impart an immediate threat to trauma patients after chest injuries. However, the amount of pleural air may increase and become a concern for patients who require positive pressure ventilation or air ambulance transport. Lung ultrasonography (US) is a reliable tool in finding intrapleural air, but the performance characteristics regarding the detection of small PTXs need to be defined. The study aimed to define the volume threshold of intrapleural air when PTXs are accurately diagnosed with US and compare this volume with that for chest x-ray (CXR).

Methods

Air was insufflated into a unilateral pleural catheter in seven incremental steps (10, 25, 50, 100, 200, 350 and 500 mL) in 20 intubated porcine models, followed by a diagnostic evaluation with US and a supine anteroposterior CXR. The sonographers continued the US scanning until the PTXs could be ruled in, based on the pathognomonic US “lung point” sign. The corresponding threshold volume was noted. A senior radiologist interpreted the CXR images.

Results

The mean threshold volume to confirm the diagnosis of PTX using US was 18 mL (standard deviation of 13 mL). Sixty-five percent of the PTXs were already diagnosed at 10 mL of intrapleural air; 25%, at 25 mL; and the last 10%, at 50 mL. At an air volume of 50 mL, the radiologist only identified four out of 20 PTXs in the CXR pictures; i.e., a sensitivity of 20% (95% CI: 7%, 44%). The sensitivity of CXR increased as a function of volume but leveled off at 67%, leaving one-third (1/3) of the PTXs unidentified after 500 mL of insufflated air.

Conclusion

Lung US is very accurate in diagnosing even small amounts of intrapleural air and should be performed by clinicians treating chest trauma patients when PTX is among the differential diagnoses.

A Virtual Reality Patient Simulation System for Teaching Emergency Response Skills to U.S. Navy Medical Providers

Rapid and effective medical intervention in response to civil and military-related disasters is crucial for saving lives and limiting long-term disability. Inexperienced providers may suffer in performance when faced with limited supplies and the demands of stabilizing casualties not generally encountered in the comparatively resource-rich hospital setting. Head trauma and multiple injury cases are particularly complex to diagnose and treat, requiring the integration and processing of complex multimodal data. In this project, collaborators adapted and merged existing technologies to produce a flexible, modular patient simulation system with both three-dimensional virtual reality and two-dimensional flat screen user interfaces for teaching cognitive assessment and treatment skills. This experiential, problem-based training approach engages the user in a stress-filled, high fidelity world, providing multiple learning opportunities within a compressed period of time and without risk. The system simulates both the dynamic state of the patient and the results of user intervention, enabling trainees to watch the virtual patient deteriorate or stabilize as a result of their decision-making speed and accuracy. Systems can be deployed to the field enabling trainees to practice repeatedly until their skills are mastered and to maintain those skills once acquired. This paper describes the technologies and the process used to develop the trainers, the clinical algorithms, and the incorporation of teaching points. We also characterize aspects of the actual simulation exercise through the lens of the trainee.

A porcine pneumothorax model for teaching ultrasound diagnostics

Objectives: Ultrasound (US) is a sensitive diagnostic tool for detecting pneumothorax (PTX), but methods are needed to optimally teach this technique outside of direct patient care. In training and research settings, porcine PTX models are sometimes used, but the description of the PTX topography in these models is lacking. The study purpose was to define the distribution of air using the reference imaging standard computed tomography (CT), to see if pleural insufflation of air into a live anaesthetized pig truly imitates a PTX in an injured patient.

Methods: A unilateral catheter was inserted into one pleural cavity of each of 20 pigs, and 500 mL of air was insufflated. After a complete thoracic CT scan, the anterior, lateral, medial, basal, apical, and posterior components of the PTXs were compared. The amount of air in each location was quantified by measuring the distance from the lung edge to the chest wall (LE-CW). A supine anteroposterior chest radiograph (CXR) was taken from each model and interpreted by a senior radiologist, and the image results were compared to CT.

Results: All 20 hemithoraces with PTX were correctly identified by CT, while six remained occult after interpreting the CXRs. The PTXs were anterior (100%), lateral (95%), medial (80%), basal (60%), apical (45%), and posterior (15%). The major proportion of the insufflated 500-mL volume was found in the anterior, medial, and basal recesses.

Conclusions: The authors found the distribution of the intrathoracic air to be similar between a porcine model and that to be expected in human trauma patients, all having predominantly anterior PTX topographies. In a training facility, the model is easy to set up and can be scanned by the participants multiple times. To acquire the necessary skills to perform thoracic US examinations for PTX, the porcine models could be useful.

Do mannequin chests provide an accurate representation of a human chest for simulated decompression of tension pneumothoraxes?

BACKGROUND

Tension pneumothorax (TPX) is an uncommon but life-threatening condition. It is important that this uncommon presentation, managed by needle decompression, is practised by paramedics using a range of educationally sound and realistic mannequins. The objective of this study is to identify if the chest wall thickness (CWT) of training mannequins used for chest decompression is an anatomically accurate representation of a human chest.

METHODS

This is a two-part study. A review of the literature was conducted to identify chest wall thickness in humans and measurement of chest wall thickness on two commonly used mannequins. The literature search was conducted using the Cochrane Central Register of Controlled Trials, MEDLINE, CINAHL, and EMBASE databases from their beginning until the end of May 2012. Key words included chest wall thickness, tension pneumothorax, pneumothorax, thoracostomy, needle thoracostomy, decompression, and needle test. Studies were included if they reported chest wall thickness.

RESULTS

For the literature review, 4 461 articles were located with 9 meeting the inclusion criteria. Chest wall thickness in adults varied between 1.3 cm and 9.3 cm at the area of the second intercostal space mid clavicular line. The Laerdal(®) manikin in the area of the second intercostal space mid clavicular line, right side of the chest was 1.1 cm thick with the left 1.5 cm. The MPL manikin in the same area or on the right side of the chest was 1.4 cm thick but on the left 1.0 cm.

CONCLUSION

Mannequin chests are not an accurate representation of the human chest when used for decompressing a tension pneumothorax and therefore may not provide a realistic experience.

Initial management and resuscitation of severe chest trauma

Severe chest trauma, blunt or penetrating, is responsible for up to 25% of traumatic deaths in North America. Respiratory compromise is the most frequent dramatic presentation in blunt trauma, while injuries to the heart and great vessels pose the greatest risk of immediate death following penetrating trauma. More than 80% of patients will be managed with interventions that can be performed in the emergency department. This article reviews the presentation, diagnosis, and management of the most important thoracic injuries. A structured approach to the acutely unstable patient is proposed to guide resuscitation decisions.

Pneumothorax during laparoscopic totally extraperitoneal inguinal hernia repair -A case report-

We experienced an extremely rare complication during performance of laparoscopic totally extraperitoneal (TEP) inguinal hernia repair for a 57-year-old healthy man. About 50 minutes after CO₂ insufflation, the patient developed tachycardia, hypoxemia, hypercapnia and an increased airway pressure. Right pneumothorax with subcutaneous emphysema was recognized on the emergency chest X-ray and this was successfully treated by chest tube insertion. Anesthesiologists should be aware of the possible occurrence of pneumothorax during laparoscopic TEP hernia repair.

A rare anesthetic complication involving central line access during lumbar spine surgery: a case report and review

STUDY DESIGN

A case report describing a rare perioperative complication involving the intrathoracic placement of a central venous catheter during spine surgery leading to hemodynamic instability.

OBJECTIVE

To review the efficacy of central line use in perioperative spine patients and to describe the diagnosis, emergent treatment, and postoperative care of a unique case of intrathoracic extravasation of propofol.

SUMMARY OF BACKGROUND DATA

Although placement of central line access is a safe procedure, complications can occur. A case in which a venous catheter delivering propofol into the thorax has never been documented.

METHODS

A 48-year-old woman presented for revision spine surgery, and a central line was placed. After placement of spinal instrumentation, she became hemodynamically unstable secondary to mediastinal compression caused by pressure from intraoperative propofol and fluid insufflation.

RESULTS

A chest tube was placed, and with aggressive pulmonary toilet and physical therapy, she did well and was discharged without noted symptoms.

CONCLUSION

The efficacy of central line use should be carefully considered in perioperative spine surgery, and in patients with significant risk factors, placement of central venous access should be radiographically confirmed.

Radiologic assessment of potential sites for needle decompression of a tension pneumothorax

BACKGROUND

The recommended treatment of suspected tension pneumothorax is immediate needle decompression. Recommended sites and needle sizes for this procedure vary, and there are published reports of failed decompression as well as iatrogenic hemothorax. We investigated the optimal needle length and relative safety of three potential needle decompression sites.

METHODS

Using thoracic computed tomography scans of 100 adults, we measured the distance from skin surface to pleura and to intrathoracic structures at the level of the sternal angle at the midhemithoracic line (MHL), and at the level of the xiphoid process at the anterior axillary and midaxillary lines, as well as the distance from the sternal midline to internal mammary vessels.

RESULTS

Median distances from the midline to the MHL and internal mammary vessels were 6.1 and 3.0 cm, respectively. Median (range) depth-to-pleura below the skin surface at the MHL, midaxillary lines, and anterior axillary line sites was 3.1 (1.4-6.9), 3.5 (1.7-9.3+), and 2.6 (1.0-7.7+) cm, respectively. Overall, there was a lower margin of safety on the left side compared with the right side, and the MHL site was safest on both sides.

CONCLUSIONS

Needle decompression of suspected tension pneumothorax should be attempted in the MHL at the level of the sternal angle using a needle at least 7 cm long inserted perpendicular to the horizontal plane. This approach should yield the highest success rate and margin of safety compared with other sites.

Pre-hospital pleural decompression and chest tube placement after blunt trauma: A systematic review

Pre-hospital insertion of chest tubes or decompression of air within the pleural space is one of the controversial topics in emergency medical care of trauma patients. While a wide variety of opinions exist medical personnel on the scene require guidance in situations when tension pneumothorax or progressive pneumothorax is suspected. To ensure evidence based decisions we performed a systematic review of the current literature with respect to the diagnostic accuracy in the pre-hospital setting to identify patients with (tension) pneumothorax, the efficacy and safety of performing pleural decompression in the field and the choice of method and technique for the procedure. The evidence found is presented and discussed and recommendations are drawn from the authors' perspective.

Prehospital intubation and chest decompression is associated with unexpected survival in major thoracic blunt trauma

OBJECTIVE

Application of the Trauma and Injury Severity Score (TRISS) to a trauma population identifies patients with 'unexpected survival'. This study used TRISS analysis to identify 'unexpected survivors' suffering major thoracic trauma, who survived to hospital discharge. Further analysis determined prehospital interventions that appeared to contribute to 'unexpected survival'.

METHODS

The present study was a single-centre, retrospective case review with comparative statistical analysis. Patients were identified from the Alfred Trauma Registry between 1 July 2002 and 30 June 2003.

RESULTS

There were 336 adult trauma patients treated at The Alfred Trauma Centre with an Injury Severity Score >15 (major trauma) and at least one thoracic Anatomical Injury Score of 3 (severe) or greater. Of the eligible patients, 322/336 (95.8%, 95%[confidence interval] CI 95.1-96.5%) had complete data available for analysis. The study population mortality was 42/322 (13.0%, 95% CI 12.3-13.7%). There were 20 'unexpected survivors' (5.9%) and 5 (1.5%) 'unexpected deaths' on TRISS analysis. Chest decompression and/or endotracheal intubation prehospital was performed on 16/20 'unexpected survivors'. GCS for 'unexpected survivors' and 'expected deaths' (3.8 vs 3.5, P = 0.27) was not a predictor of survival. Respiratory rate per minute (16.2 vs 8.8, P = 0.01) and systolic blood pressure - mmHg (98 vs 80, P = 0.03) were significantly greater in the 'unexpected survivors' group compared with the 'expected death' group.

CONCLUSION

For patients sustaining severe thoracic blunt trauma, prehospital intubation and chest decompression appear to be associated with unexpected survival. A low GCS at scene is not predictive of 'unexpected survival' or 'expected death'.

Uncertainties in the current understanding of gas exchange in spontaneous pneumothorax: effective lung ventilation may persist in a smaller-sized pneumothorax

Clinical aspects of spontaneous pneumothorax (SP) are far more clear than some patophysiological issues. The exact mechanism that maintains adequate oxygenation in spontaneous pneumothorax of lesser size is still unclear. Experimental and rare studies in humans could not explicitely confirm whether it is hyperventilation of the nonaffected lung, still effective gas exchange within the affected lung, or hypoxic vasoconstriction. Similarly, it is unclear why the severity of dyspnoea sometimes differs between patients with the same size of SP. The idea that a certain degree of effective lung ventilation might exist in SP of lesser size was based on clinical observation of these patients on admission, on our measurements of pleural pressures and oxygenation in a group of patients with SP of different size and on rare experimental studies. Clinical observation that oxygenation was not significantly impaired in patients with SP of lesser size, without documented hyperventilation, served as a base for critical analysis of possible factors influencing oxygenation in SP of lesser size. Our hypothesis that pleural pressure swings in a partially collapsed lung, but still slightly expanding in inspiration, enable a certain degree of gas exchange, was confirmed both by several experimental studies and by our measurements. On the other hand, our clinical observation that patients with SP of greater size frequently differ in the severity of dyspnoea suggested the need of a more detailed analysis of the causes of hypoxaemia in these patients. The fact that hypoxaemia in these patients usually cannot be abolished by the existing hyperventilation, means that in SP of greater size, despite minimal lung volume, circulation in the pulmonary artery system still exists, causing right to left blood shunting. The fact that the severity of dyspnoea is not equal in all patients with complete SP means that hypoxic vasoconstriction exists only in some of them, following a still unknown pattern. Literature data and our measurements suggest that without further studies of hypoxic vasoconstriction in the acute phase of SP, the exact answer is not possible.

Tension pneumothorax--time for a re-think?

This review examines the present understanding of tension pneumothorax and produces recommendations for improving the diagnostic and treatment decision process.

Accidentally created tension pneumothorax in patient with primary spontaneous pneumothorax – confirmation of the experimental studies, putting into question the classical explanation

BACKGROUND

The widespread explanation of patophysiology of tension pneumothorax is that compression to the mediastinum by the progressively accumulating intrapleural air causes torsion at the atrio-caval junction, impaired filling of the right heart and circulatory arrest as potentially life-threatening complication. Some experimental studies on animals put into question such an explanation, suggesting that respiratory arrest due to hypoxia of the respiratory center, not a circulatory arrest, represents dominant life threatening feature.

CASE REPORT

we present a patient with spontaneous pneumothorax in whom tension pneumothorax occurred accidentally, i.e., in whom air was insufflated under great pressure from the aspirating system into the pleural cavity, immediately after insertion of a chest tube. As the situation was recognized immediately, urgent reanimation was undertaken--endotracheal intubation, ventilation through the balloon, reconnection of the chest tube to another aspirating system. Lung reexpansion was achieved and the patient was discharged after an uneventful course. In this patient, it was possible to register the sequence of events before, during and after the incident. Dominant clinical finding during resuscitation of this apnoic, cyanotic and unconscious patient was respiratory arrest in presence of evident maintenance of peripheral circulation, that supports results of experimental studies. Dominant findings in experiments with creation of tension pneumothorax was that, although pressures rose throughout the right side of the circulation, no developing pressure gradient was found on this side of the circulation; furthermore, respiratory arrest preceded cardiac arrest in these animals. Hypoxia of the respiratory center, caused by the increasing portion of pulmonary blood flow being shunted through nonventilated or hypoventilated lung, was suggested as primary cause of death of experimental animals. The same factor seems to be a cause of respiratory arrest in our patient.

CONCLUSION

respiratory arrest, preceding circulatory arrest, seems to be the principal life threatening condition in patients with progressive tension pneumothorax.

Pneumothorax and pneumomediastinum

Pneumothorax and pneumomediastinum occur uncommonly in association with athletic participation. Although they are rare, when they occur they can be life-threatening, requiring immediate diagnosis and treatment. These injuries also present difficult return-to-play decisions for the sports medicine physician. There are sparse data to help determine the incidence of these injuries in sport, as well as their optimal treatment. Although most sports physicians have seen these injuries, not many have seen enough to publish a large series discussing optimal management or make return-to-play recommendations.