Needle versus Tube Thoracostomy in a Swine Model of Traumatic Tension Hemopneumothorax

[Cardiac arrest under special circumstances]

These guidelines of the European Resuscitation Council (ERC) Cardiac Arrest under Special Circumstances are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the modifications required for basic and advanced life support for the prevention and treatment of cardiac arrest under special circumstances; in particular, specific causes (hypoxia, trauma, anaphylaxis, sepsis, hypo-/hyperkalaemia and other electrolyte disorders, hypothermia, avalanche, hyperthermia and malignant hyperthermia, pulmonary embolism, coronary thrombosis, cardiac tamponade, tension pneumothorax, toxic agents), specific settings (operating room, cardiac surgery, cardiac catheterization laboratory, dialysis unit, dental clinics, transportation [in-flight, cruise ships], sport, drowning, mass casualty incidents), and specific patient groups (asthma and chronic obstructive pulmonary disease, neurological disease, morbid obesity, pregnancy).

European Resuscitation Council Guidelines 2021: Cardiac arrest in special circumstances

These European Resuscitation Council (ERC) Cardiac Arrest in Special Circumstances guidelines are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the modifications required to basic and advanced life support for the prevention and treatment of cardiac arrest in special circumstances; specifically special causes (hypoxia, trauma, anaphylaxis, sepsis, hypo/hyperkalaemia and other electrolyte disorders, hypothermia, avalanche, hyperthermia and malignant hyperthermia, pulmonary embolism, coronary thrombosis, cardiac tamponade, tension pneumothorax, toxic agents), special settings (operating room, cardiac surgery, catheter laboratory, dialysis unit, dental clinics, transportation (in-flight, cruise ships), sport, drowning, mass casualty incidents), and special patient groups (asthma and COPD, neurological disease, obesity, pregnancy).

Comparison of 10- versus 14-gauge angiocatheter for treatment of tension pneumothorax and tension-induced pulseless electrical activity with hemorrhagic shock: Bigger is still better

BACKGROUND

Little is known regarding the effect of hemorrhagic shock on the diagnosis and treatment of tension pneumothorax (tPTX). Recently, the Tactical Combat Casualty Care guidelines included the 10-gauge angiocatheter (10-g AC) as an acceptable alternative to the 14-g AC. This study sought to compare these two devices for decompression of tPTX and rescue from tension-induced pulseless electric activity (tPEA) in the setting of a concomitant 30% estimated blood volume hemorrhage.

METHODS

Following a controlled hemorrhage, carbon dioxide was insufflated into the chest to induce either tPTX or tPEA. Tension pneumothorax was defined as a reduction in cardiac output by 50%, and tPEA was defined as a loss of arterial waveform with mean arterial pressure less than 20 mm Hg. The affected hemithorax was decompressed using a randomized 14-g AC or 10-g AC while a persistent air leak was maintained after decompression. Successful rescue from tPTX was defined as 80% recovery of baseline systolic blood pressure, while successful return of spontaneous circulation following tPEA was defined as a mean arterial pressure greater than 20 mm Hg. Primary outcome was success of device.

RESULTS

Eighty tPTX and 50 tPEA events were conducted in 38 adult Yorkshire swine. There were no significant differences in the baseline characteristics between animals or devices. In the tPTX model, the 10-g AC successfully rescued 90% of events, while 14-g AC rescued 80% of events (p = 0.350). In the tPEA model, the 10-g AC rescued 87% of events while the 14 AC rescued only 48% of events (p = 0.006).

CONCLUSION

The 10-g AC was vastly superior to the 14-g AC for return of spontaneous circulation following tPEA in the setting of 30% hemorrhage. These findings further support the importance of larger caliber devices that facilitate rapid recovery from tPTX, particularly in the setting of polytrauma.

LEVEL OF EVIDENCE

Therapeutic, level II.

Iatrogenic emergency medicine procedure complications and associated trouble-shooting strategies

PURPOSE

The purpose of this paper is to provide a consolidated reference for the acute management of selected iatrogenic procedural injuries occurring in the emergency department (ED).

DESIGN/METHODOLOGY/APPROACH

A literature search was performed utilizing PubMed, Scopus, Web of Science and Google Scholar for studies through March of 2017 investigating search terms "iatrogenic procedure complications," "error management" and "procedure complications," in addition to the search terms reflecting case reports involving the eight below listed procedure complications.

FINDINGS

This may be particularly helpful to academic faculty who supervise physicians in training who present a higher risk to cause such injuries.

ORIGINALITY/VALUE

Emergent procedures performed in the ED present a higher risk for iatrogenic injury than in more controlled settings. Many physicians are taught error-avoidance rather than how to handle errors when learning procedures. There is currently very limited literature on the error management of iatrogenic procedure complications in the ED.

Transoceanic Telementoring of Tube Thoracostomy Insertion: A Randomized Controlled Trial of Telementored Versus Unmentored Insertion of Tube Thoracostomy by Military Medical Technicians

Background: Tension pneumothorax is a frequent cause of potentially preventable death. Tube thoracostomy (TT) can obviate death but is invasive and fraught with complications even in experienced hands. We assessed the utility of a remote international virtual network (RIVN) of specialized mentors to remotely guide military medical technicians (medics) using wireless informatics. Methods: Medics were randomized to insert TT in training mannequins (TraumaMan; Abacus ALS, Meadowbrook, Australia) supervised by RIVN or not. The RIVN consisted of trauma surgeons in Canada and Australia and a senior medic in Ohio. Medics wore a helmet-mounted wireless camera with laser pointer to confirm anatomy and two-way voice communication using commercial software (Skype^®). Performance was measured through objective task completion (pass/fail) regarding safety during the procedure, proper location, and secure anchoring of the tube, in addition to remote mentor opinion and subjective debrief. Results: Fourteen medics attempted TT, seven mentored and seven not. The RIVN was functional and surgeons on either side of the globe had real-time communication with the mentees. TT placement was considered safe, successful, and secure in 100% of mentored (n = 7) procedures, although two (29%) received corrective remote guidance. All (100%) of the unmentored attempted and adequately secured the TT and were safe. However, only 71% (n = 5) completed the task successfully (p = 0.46). Participating medics subjectively felt remote telementoring (RTM) increased self-confidence (strong agreement mean 5/5 ± 0); confidence to perform field TT (agreement (4/5 ± 1); and decreased anxiety (strong agreement 5/5 ± 1). Subjectively, the remote mentors felt in 100% of the mentored procedures that "yes" they were able to assist the medics (1.86 ± 0.38), and in 71% (n = 5) felt "yes" they made TT safer (2.29 ± 0.49). Conclusions: RTM descriptively increased the success of TT placement and allowed for real-time troubleshooting from thousands of kilometers with a redundant capability. RTM was subjectively associated with high levels of satisfaction and self-reported self-confidence. Continued controlled and critical evaluation and refinement of telemedical techniques should continue. Trial Registration: ID ISRCTN/77929274.

Reduced right ventricular diameter during cardiac arrest caused by tension pneumothorax - a porcine ultrasound study

INTRODUCTION

Advanced life support (ALS) guidelines recommend ultrasound to identify reversible causes of cardiac arrest. Right ventricular (RV) dilatation during cardiac arrest is commonly interpreted as a sign of pulmonary embolism. The RV is thus a focus of clinical ultrasound examination. Importantly, in animal studies ventricular fibrillation and hypoxia results in RV dilatation. Tension pneumothorax (tPTX) is another reversible cause of cardiac arrest, however, the impact on RV diameter remains unknown.

AIM

To investigate RV diameter evaluated by ultrasound in cardiac arrest caused by tPTX or hypoxia.

METHODS

Pigs were randomized to cardiac arrest by either tPTX (n = 9) or hypoxia (n = 9) and subsequently resuscitated. Tension pneumothorax was induced by injection of air into the pleural cavity. Hypoxia was induced by reducing tidal volume. Ultrasound images of the RV were obtained throughout the study. Tension pneumothorax was decompressed after the seventh rhythm analysis. The primary endpoint was RV diameter after the third rhythm analysis.

RESULTS

At cardiac arrest the RV diameter was 17 mm (95% CI: 13; 21) in the tPTX group and 36 mm (95% CI: 33; 40) in the hypoxia group (P < 0.01, n = 9 for both). At third rhythm analysis RV diameter was smaller in the tPTX group: 12 mm (95% CI: 7; 16) vs. hypoxia group: 28 mm (25; 32) (P < 0.01). After decompression no difference existed between groups: tPTX 29 mm (95% CI: 23; 34) vs. hypoxia 29 mm (95% CI: 20; 38).

CONCLUSION

The RV diameter is smaller during cardiopulmonary resuscitation in cardiac arrest caused by tPTX when compared with hypoxia. The difference disappears after tPTX decompression.

Do vented chest seals differ in efficacy? An experimental evaluation using a swine hemopneumothorax model

OBJECTIVE

Airways compromise was the second leading cause of potentially preventable death among combat casualties. We investigated the ability of five Food and Drug Administration-approved nonocclusive chest seals (CSs) to seal a bleeding chest wound and prevent tension hemopneumothorax (HPTX) in a swine model.

METHODS

Following instrumentation, an open chest wound was created in the left thorax of spontaneously air-breathing anesthetized pigs (n = 26; 43 kg). Autologous fresh blood (226 mL) was then infused into the pleural cavity to produce HPTX. The chest wounds were then sealed with CSs. The sealant strength and venting function of CSs were challenged by infusion of 50 mL more blood directly into the chest wound and incremental air injections into the pleural cavity. Tension HPTX was defined as intrapleural (IP) pressure equal to or more than +1 mm Hg and more than 20% deviation in physiologic measurements.

RESULTS

An open chest wound with HPTX raised IP pressure (~ -0.7 mm Hg) and caused labored breathing and reductions in PaO2 and SvO2 (p < 0.01). Sealing the wounds with the CSs restored IP pressure, and improved breathing and oxygenation. Subsequent blood infusion into the wound and IP air injections produced CS-dependent responses. Chest seals with one-way valves (Bolin and SAM) did not evacuate the blood efficiently; pooled blood either detached the CSs from skin and leaked out (75%), or clotted and clogged the valve and led to tension HPTX (25%). Conversely, CSs with laminar venting channels allowed escape of blood and air from the pleural cavity and maintained IP pressure and oxygenation near normal levels. Success rates were 100% for Sentinel and Russell (6/6); 67% for HyFin (4/6); 25% for SAM (1/4); and 0% for Bolin (0/4) CSs (p = 0.002).

CONCLUSION

The sealant and valve function of vented CS differed widely in the presence of bleeding chest wounds. Medics should be equipped with more effective CSs for treating HPTX in the field.

Failure rate of prehospital chest decompression after severe thoracic trauma

INTRODUCTION

Chest decompression can be performed by different techniques, like needle thoracocentesis (NT), lateral thoracostomy (LT), or tube thoracostomy (TT). The aim of this study was to report the incidence of prehospital chest decompression and to analyse the effectiveness of these techniques.

MATERIAL AND METHODS

In this retrospective case series study, all medical records of adult trauma patients undergoing prehospital chest decompression and admitted to the resuscitation area of a level-1 trauma center between 2009 and 2015 were reviewed and analysed. Only descriptive statistics were applied.

RESULTS

In a 6-year period 24 of 2261 (1.1%) trauma patients had prehospital chest decompression. Seventeen patients had NT, six patients TT, one patient NT as well as TT, and no patients had LT. Prehospital successful release of a tension pneumothorax was reported by the paramedics in 83% (5/6) with TT, whereas NT was effective in 18% only (3/17). In five CT scans all thoracocentesis needles were either removed or extrapleural, one patient had a tension pneumothorax, and two patients had no pneumothorax. No NT or TT related complications were reported during hospitalization.

CONCLUSION

Prehospital NT or TT is infrequently attempted in trauma patients. Especially NT is associated with a high failure rate of more than 80%, potentially due to an inadequate ratio between chest wall thickness and catheter length as previously published as well as a possible different pathophysiological cause of respiratory distress. Therefore, TT may be considered already in the prehospital setting to retain sufficient pleural decompression upon admission.

Standard laparoscopic trocars for the treatment of tension pneumothorax: a superior alternative to needle decompression

BACKGROUND

Needle thoracostomy (NT) is a commonly taught intervention for tension pneumothorax (tPTX) but has a high failure rate. We hypothesize that standard 5-mm laparoscopic trocars may be a safe and more effective alternative.

METHODS

Thirty episodes of tPTX and 27 episodes of tension-induced pulseless electrical activity (PEA) were induced in five adult swine using thoracic CO2 insufflation via balloon trocar. Tension was defined as a 50% decrease in cardiac output. Chest decompression was performed with 5-mm laparoscopic trocars for the treatment of both tPTX with hemodynamic compromise and tension-induced PEA. The lungs and heart were inspected and graded at necropsy for trocar-related injury. Results were also compared with success rates with NT in the same model.

RESULTS

The placement of a 5-mm trocar rapidly and immediately relieved tension physiology in 100% of the cases. Mean arterial pressure, cardiac output, central venous pressure, and pulmonary capillary wedge pressure all returned to baseline within 1 minute of trocar placement. Adequate perfusion was restored in 100% of tension-induced PEA cases within 30 seconds of trocar placement. There was no evidence of trocar-related heart or lung damage in any of the experimental animals at necropsy (mean injury scores, 0 for both). Five-millimeter trocars significantly outperformed standard NT for both tPTX and tension-induced PEA arrest.

CONCLUSION

tPTX and tension-induced PEA can be safely and effectively treated with chest decompression using 5-mm laparoscopic trocars. This technique may serve as a more rapid and reliable alternative to needle decompression.

Vented versus unvented chest seals for treatment of pneumothorax and prevention of tension pneumothorax in a swine model

BACKGROUND

Unvented chest seals (CSs) are currently recommended for the management of penetrating thoracic injuries in the battlefield. Since no supporting data exist, we compared the efficacy of a preferred unvented with that of a vented CS in a novel swine model of pneumothorax (PTx).

METHODS

An open chest wound was created in the left thorax of spontaneously air-breathing anesthetized pigs (n = 8). A CS was applied over the injury, then tension PTx was induced by incremental air injections (0.2 L) into the pleural cavity via a cannula that was also used to measure intrapleural pressure (IP). Both CS were tested on each pig in series. Tidal volume (V(T)), respiratory rate, IP, heart rate, mean arterial pressure, cardiac output, central venous pressure, pulmonary arterial pressure, venous and peripheral oxygen saturations (SvO2, SpO2) were recorded. Tension PTx was defined as a mean IP equal to or greater than +1 mm Hg plus significant (20-30%) deviation in baseline levels of the previously mentioned parameters and confirmed by chest x-ray study. PaO2 and PaCo2 were also measured.

RESULTS

PTx produced immediate breathing difficulty and significant rises in IP and pulmonary arterial pressure and falls in V(T), SpO2, and SvO2. Both CSs returned these parameters to near baseline within 5 minutes of application. After vented CS was applied, serial air injections up to 2 L resulted in no significant change in the previously mentioned parameters. After unvented CS application, progressive deterioration of all respiratory parameters and onset of tension PTx were observed in all subjects after approximately 1.4-L air injection.

CONCLUSION

Both vented and unvented CSs provided immediate improvements in breathing and blood oxygenation in our model of penetrating thoracic trauma. However, in the presence of ongoing intrapleural air accumulation, the unvented CS led to tension PTx, hypoxemia, and possible respiratory arrest, while the vented CS prevented these outcomes.

Development of a simple algorithm to guide the effective management of traumatic cardiac arrest

BACKGROUND

Major trauma is the leading worldwide cause of death in young adults. The mortality from traumatic cardiac arrest remains high but survival with good neurological outcome from cardiopulmonary arrest following major trauma has been regularly reported. Rapid, effective intervention is required to address potential reversible causes of traumatic cardiac arrest if the victim is to survive. Current ILCOR guidelines do not contain a standard algorithm for management of traumatic cardiac arrest. We present a simple algorithm to manage the major trauma patient in actual or imminent cardiac arrest.

METHODS

We reviewed the published English language literature on traumatic cardiac arrest and major trauma management. A treatment algorithm was developed based on this and the experience of treatment of more than a thousand traumatic cardiac arrests by a physician - paramedic pre-hospital trauma service.

RESULTS

The algorithm addresses the need treat potential reversible causes of traumatic cardiac arrest. This includes immediate resuscitative thoracotomy in cases of penetrating chest trauma, airway management, optimising oxygenation, correction of hypovolaemia and chest decompression to exclude tension pneumothorax.

CONCLUSION

The requirement to rapidly address a number of potentially reversible pathologies in a short time period lends the management of traumatic cardiac arrest to a simple treatment algorithm. A standardised approach may prevent delay in diagnosis and treatment and improve current poor survival rates.

Emergency medicine techniques and the forensic autopsy

Emergency medicine measures often have to be carried out under suboptimal conditions in emergency situations and require invasive patient treatment. In the case of a fatal outcome these measures have to be evaluated at autopsy, regarding indications, correct implementation and possible complications. As well, alongside the more familiar procedures--such as endotracheal intubation, insertion of chest drains, external cardiac massage and cannulation of central and peripheral veins--there are alternative techniques being increasingly applied, that include new tools for the management of hemorrhagic shock, drug delivery and alternative airway management devices. On the one hand, all of these measures are essential for the survival and appropriate treatment of the injured and/or sick patient, but on the other hand they can damage the patient and thus contain a significant risk of both medical and forensic relevance for the patient and the physician. In the following review we provide an overview of established, new and alternative techniques for emergency airway management, administration of drugs and management of hemorrhagic shock. The aim is to facilitate the understanding and autopsy evaluation of current emergency medicine techniques.

Needle decompression for tension pneumothorax in Tactical Combat Casualty Care: do catheters placed in the midaxillary line kink more often than those in the midclavicular line?

BACKGROUND

Tactical Combat Casualty Care (TCCC) is a system of prehospital trauma care designed for the combat environment. Needle decompression (ND) is a critical TCCC intervention, because previous data suggest that up to 33% of all preventable deaths on the battlefield result from tension pneumothoraces. There has recently been increased interest in performing ND at the fifth intercostal space in the midaxillary line to prevent complications associated with landmarking second intercostal space in the midclavicular line site. We developed a model to assess whether catheters placed in the midaxillary line for decompressing tension pneumothoraces are more prone to kinking than those placed in the midclavicular line because of adducted arms during military transport.

METHODS

To simulate ND, we secured segments of porcine chest walls over volunteer soldiers' chests and placed 14-gauge, 1.5-inch angiocatheters through the porcine wall segments which were affixed to either the midaxillary or midclavicular location on the volunteers. We then assessed for occlusion and kinking by flow of normal saline (NS) through the angiocatheter in situ. The angiocatheter was then transduced using standard arterial line manometry, and the opening pressures required to initiate flow through the catheters were measured. The opening pressures were then converted to mm Hg. We also assessed for catheter occlusion after the physical manipulation of the patient, by simulated patient transport.

RESULTS

We observed that there was a significant pressure difference required to achieve free flow through the in situ angiocatheter between the fifth intercostal space midaxillary line versus the second intercostal space midclavicular line site (13.1 ± 3.6 mm Hg vs. 7.9 ± 1.8 mm Hg).

CONCLUSIONS

This study suggests that the 14-gauge, 1.5-inch angiocatheter used for ND in the midaxillary line may partially and temporarily occlude in patients who will be transported on military stretchers. The pressure of 12.8 mm Hg has been documented in animal models as the pressure at which hemodynamic instability develops. This may contribute to the reaccumulation of tension pneumothoraces and ultimate patient deterioration in military transport.

Optimal positioning for emergent needle thoracostomy: a cadaver-based study

BACKGROUND

Needle thoracostomy is an emergent procedure designed to relieve tension pneumothorax. High failure rates because of the needle not penetrating into the thoracic cavity have been reported. Advanced Trauma Life Support guidelines recommend placement in the second intercostal space, midclavicular line using a 5-cm needle. The purpose of this study was to evaluate placement in the fifth intercostal space, midaxillary line, where tube thoracostomy is routinely performed. We hypothesized that this would result in a higher successful placement rate.

METHODS

Twenty randomly selected unpreserved adult cadavers were evaluated. A standard 14-gauge 5-cm needle was placed in both the fifth intercostal space at the midaxillary line and the traditional second intercostal space at the midclavicular line in both the right and left chest walls. The needles were secured and thoracotomy was then performed to assess penetration into the pleural cavity. The right and left sides were analyzed separately acting as their own controls for a total of 80 needles inserted into 20 cadavers. The thickness of the chest wall at the site of penetration was then measured for each entry position.

RESULTS

A total of 14 male and 6 female cadavers were studied. Overall, 100% (40 of 40) of needles placed in the fifth intercostal space and 57.5% (23 of 40) of the needles placed in the second intercostal space entered the chest cavity (p < 0.001); right chest: 100% versus 60.0% (p = 0.003) and left chest: 100% versus 55.0% (p = 0.001). Overall, the thickness of the chest wall was 3.5 cm ± 0.9 cm at the fifth intercostal space and 4.5 cm ± 1.1 cm at the second intercostal space (p < 0.001). Both right and left chest wall thicknesses were similar (right, 3.6 cm ± 1.0 cm vs. 4.5 cm ± 1.1 cm, p = 0.007; left, 3.5 ± 0.9 cm vs. 4.4 cm ± 1.1 cm, p = 0.008).

CONCLUSIONS

In a cadaveric model, needle thoracostomy was successfully placed in 100% of attempts at the fifth intercostal space but in only 58% at the traditional second intercostal position. On average, the chest wall was 1 cm thinner at this position and may improve successful needle placement. Live patient validation of these results is warranted.