Automated balloon control in resuscitative endovascular balloon occlusion of the aorta (REBOA)

Objective: The goal of this work was to demonstrate technical feasibility of automated balloon pressure management during REBOA in the pre-clinical setting. Methods: This paper presents an intelligent balloon management device which automates the balloon inflation process, preventing the possibility of balloon over or under inflation, optimizes inflation pressure and if indicated, deflates automating partial REBOA to allow distal organ perfusion. Edwards TruWave pressure transducers are used to monitor the blood pressure proximal and distal to the balloon, as well as the internal balloon pressure. A faux PID controller, implemented on an Arduino platform, is used in a feedback control loop to allow a user defined mean arterial pressure setpoint to be reached, via a syringe driver which allows intelligent inflation and deflation of the catheter balloon. Results: Ex vivo testing on a vascular perfusion simulator provided the characteristic behavior of a fully occluded aorta, namely the decrease of distal pressure to zero. In vivo testing on live porcine models indicated that automated partial REBOA is achievable and by enabling partial occlusion may offer improved medical outcomes compared to manual control. Conclusion: Automated balloon pressure management of endovascular occlusion is feasible and can be successfully implemented without changes on current clinical workflows. Significance: With further development, automated balloon management may significantly improve clinical outcomes in REBOA

Investigating the variability in pressure–volume relationships during hemorrhage and aortic occlusion

IntroductionThe pressure–volume (P-V) relationships of the left ventricle are the classical benchmark for studying cardiac mechanics and pumping function. Perturbations in the P-V relationship (or P-V loop) can be informative and guide the management of heart failure, hypovolemia, and aortic occlusion. Traditionally, P-V loop analyses have been limited to a single-beat P-V loop or an average of consecutive P-V loops (e.g., 10 cardiac cycles). While there are several algorithms to obtain single-beat estimations of the end-systolic and end-diastolic pressure–volume relations (i.e., ESPVR and EDPVR, respectively), there remains a need to better evaluate the variations in P-V relationships longitudinally over time. This is particularly important when studying acute and transient hemodynamic and cardiac events, such as active hemorrhage or aortic occlusion. In this study, we aim to investigate the variability in P-V relationships during hemorrhagic shock and aortic occlusion, by leveraging on a previously published porcine hemorrhage model.MethodsBriefly, swine were instrumented with a P-V catheter in the left ventricle of the heart and underwent a 25% total blood volume hemorrhage over 30 min, followed by either Zone 1 complete aortic occlusion (i.e., REBOA), Zone 1 endovascular variable aortic control (EVAC), or no occlusion as a control, for 45 min. Preload-independent metrics of cardiac performance were obtained at predetermined time points by performing inferior vena cava occlusion during a ventilatory pause. Continuous P-V loop data and other hemodynamic flow and pressure measurements were collected in real-time using a multi-channel data acquisition system.ResultsWe developed a custom algorithm to quantify the time-dependent variance in both load-dependent and independent cardiac parameters from each P-V loop. As expected, all pigs displayed a significant decrease in the end-systolic pressures and volumes (i.e., ESP, ESV) after hemorrhage. The variability in response to hemorrhage was consistent across all three groups. However, upon introduction of REBOA, we observed significantly high levels of variability in both load-dependent and independent cardiac metrics such as ESP, ESV, and the slope of ESPVR (Ees). For instance, pigs receiving REBOA experienced a 342% increase in ESP from hemorrhage, while pigs receiving EVAC experienced only a 188% increase. The level of variability within the EVAC group was consistently less than that of the REBOA group, which suggests that the EVAC group may be more supportive of maintaining healthier cardiac performance than complete occlusion with REBOA.DiscussionIn conclusion, we successfully developed a novel algorithm to reliably quantify the single-beat and longitudinal P-V relations during hemorrhage and aortic occlusion. As expected, hemorrhage resulted in smaller P-V loops, reflective of decreased preload and afterload conditions; however, the cardiac output and heart rate were preserved. The use of REBOA and EVAC for 44 min resulted in the restoration of baseline afterload and preload conditions, but often REBOA exceeded baseline pressure conditions to an alarming level. The level of variability in response to REBOA was significant and could be potentially associated to cardiac injury. By quantifying each P-V loop, we were able to capture the variability in all P-V loops, including those that were irregular in shape and believe that this can help us identify critical time points associated with declining cardiac performance during hemorrhage and REBOA use

The combination of chest compression synchronized ventilation and aortic balloon occlusion improve the outcomes of cardiopulmonary resuscitation in swine

AimThe primary mission of cardiopulmonary resuscitation (CPR) is to provide adequate blood flow and oxygen delivery for restoring spontaneous circulation from cardiac arrest (CA) events. Previously, studies demonstrated that chest compression synchronized ventilation (CCSV) improved systemic oxygen supply during CPR, and aortic balloon occlusion (ABO) augments the efficacy of external CPR by increasing blood perfusion to vital organs. However, both them failed to make a significant improvement in return of spontaneous circulation (ROSC). In this study, we investigated the effects of combined CCSV and ABO on the outcomes of CPR in swine.MethodsThirty-one male domestic swine were subjected to 8 min of electrically induced and untreated CA followed by 8 min of CPR. CPR was performed by continuous chest compressions and mechanical ventilation. At the beginning of CPR, the animals were randomized to receive intermittent positive pressure ventilation (IPPV, n = 10), CCSV (n = 7), IPPV + ABO (n = 7), or CCSV + ABO (n = 7). During CPR, gas exchange and systemic hemodynamics were measured, and ROSC was recorded. After resuscitation, the function and injury biomarkers of vital organs including heart, brain, kidney, and intestine were evaluated.ResultsDuring CPR, PaO2 was significantly higher accompanied by significantly greater regional cerebral oxygen saturation in the CCSV and CCSV + ABO groups than the IPPV group. Coronary perfusion pressure, end-tidal carbon dioxide, and carotid blood flow were significantly increased in the IPPV + ABO and CCSV + ABO groups compared with the IPPV group. ROSC was achieved in five of ten (IPPV), five of seven (CCSV), six of seven (IPPV + ABO), and seven of seven (CCSV + ABO) swine, with the rate of resuscitation success being significantly higher in the CCSV + ABO group than the IPPV group (P = 0.044). After resuscitation, significantly improved myocardial and neurological function, and markedly less cardiac, cerebral, renal, and intestinal injuries were observed in the CCSV + ABO group compared with the IPPV group.ConclusionThe combination of CCSV and ABO improved both ventilatory and hemodynamic efficacy during CPR, promoted ROSC, and alleviated post-resuscitation multiple organ injury in swine

Preparation of hospitals for mass casualty incidents in Bavaria, Germany: care capacities for penetrating injuries and explosions in TerrorMASCALs

Background In a terror attack mass casualty incident (TerrorMASCAL), compared to a “normal” MASCAL, there is a dynamic course that can extend over several hours. The injury patterns are penetrating and perforating injuries. This article addresses the provision of material and personnel for the care of special injuries of severely injured persons that may occur in the context of a TerrorMASCAL. Methods To answer the research question about the preparation of hospitals for the care of severely injured persons in a TerrorMASCAL, a survey of trauma surgery departments in Bavaria (Germany) was conducted using a questionnaire, which was prepared in three defined steps based on an expert consensus. The survey is divided into a general, neurosurgical, thoracic, vascular and trauma surgery section. In the specialized sections, the questions relate to the implementation of and material and personnel requirements for special interventions that are required, particularly for injury patterns following gunshot and explosion injuries, such as trepanation, thoracotomy and balloon occlusion of the aorta. Results In the general section, it was noted that only a few clinics have an automated system to notify off-duty staff. When evaluating the data from the neurosurgical section, the following could be established with regard to the performance of trepanation: the regional trauma centers do not perform trepanation but nevertheless have the required material and personnel available. A similar result was recorded for local trauma centers. In the thoracic surgery section, it could be determined that almost all trauma centers that do not perform thoracotomy have the required material available. This group of trauma centers also stated that they have staff who can perform thoracotomy independently. The retrograde endovascular aortic occlusion procedure is possible in 88% of supraregional, 64% of regional and 10% of local trauma centers. Pelvic clamps and external fixators are available at all trauma centers. Conclusion The results of the survey show potential for optimization both in the area of framework conditions and in the care of patients. Consistent and specific training measures, for example, could improve the nationwide performance of these special interventions. Likewise, it must be discussed whether the abovementioned special procedures should be reserved for higher-level trauma centers

Association between emergency medical service transport time and survival in patients with traumatic cardiac arrest: a Nationwide retrospective observational study

Background Patients with traumatic cardiac arrest (TCA) are known to have poor prognoses. In 2003, the joint committee of the National Association of EMS Physicians and the American College of Surgeons Committee on Trauma proposed stopping unsuccessful cardiopulmonary resuscitation (CPR) sustained for > 15 min after TCA. However, in 2013, a specific time-limit for terminating resuscitation was dropped, due to the lack of conclusive studies or data. We aimed to define the association between emergency medical services transport time and survival to demonstrate the survival curve of TCA. Methods A retrospective review of the Japan Trauma Data Bank. Inclusion criteria were age >= 16, at least one trauma with Abbreviated Injury Scale score (AIS) >= 3, and CPR performed in a prehospital setting. Exclusion criteria were burn injury, AIS score of 6 in any region, and missing data. Estimated survival rate and risk ratio for survival were analyzed according to transport time for all patients. Analysis was also performed separately on patients with sustained TCA at arrival. Results Of 292,027 patients in the database, 5336 were included in the study with 4141 sustained TCA. Their median age was 53 years (interquartile range (IQR) 36-70), and 67.2% were male. Their median Injury Severity Score was 29 (IQR 22-41), and median transport time was 11 min (IQR 6-17). Overall survival after TCA was 4.5%; however, survival of patients with sustained TCA at arrival was only 1.2%. The estimated survival rate and risk ratio for sustained TCA rapidly decreased after 15 min of transport time, with estimated survival falling below 1%. Conclusion The chances of survival for sustained TCA declined rapidly while the patient is transported with CPR support. Time should be one reasonable factor for considering termination of resuscitation in patients with sustained TCA, although clinical signs of life, and type and severity of trauma should be taken into account clinically

Management of pelvic ring injuries

Jan Lindahl: MANAGEMENT OF PELVIC RING INJURIES Unstable pelvic ring injuries are relatively rare injuries, but they constitute a major cause of death and disability in high-energy polytrauma patients Massive hemorrhage is the leading cause of potentially preventable death following a blunt pelvic trauma. The overall aim of surgical treatment for unstable pelvic ring injuries is to restore the pelvic anatomy and perform neural decompression, thus allowing normal function with a low rate of complications. This doctoral thesis was initiated to investigate the outcomes of acute and definitive management strategies for unstable pelvic ring injuries. The first study investigated the radiological and functional results of treating type B and C pelvic injuries with an anterior external fixation frame. The second study focused on identifying factors for early predictions of mortality-related outcome and prognosis in patients with pelvic fracture-related arterial bleeding that were treated with transcatheter angiographic embolization (TAE). The third study investigated the outcomes of type C pelvic fractures treated with standardized reduction and internal fixation methods. The fourth study evaluated outcomes and identified prognostic factors for operatively-treated, H-shaped sacral fractures with spinopelvic dissociation. Study I showed that an anterior external fixator failed to achieve and properly maintain reduction in 75% of type B open book injuries and in nearly all (95%) type C pelvic ring injuries. Therefore, an external frame is not a suitable method of treatment for the most unstable pelvic ring injuries as a definitive treatment. The current clinical applications of anterior pelvic external fixators comprise the resuscitation phase, initial fracture stabilization phase, and sometimes, in complex injuries (type C), the definitive phase for fixation of the anterior part of the pelvic ring, in conjunction with posterior internal fixation. Study II of pelvic fracture related arterial bleedings showed that the worst prognosis was related to exsanguinating bleeding from the main trunk of the internal or external iliac artery (large pelvic arteries) or from multiple branches of the internal or external iliac vasculature (high vessel size score). Definitive control of arterial bleeding was achieved with TAE in all patients. In massive hemorrhage with several bleeding arteries uni- or bilaterally, it is reasonable to use non-selective embolization by promptly occluding the main trunk of the internal iliac artery, either uni- or bilaterally. Study III of operatively treated type C pelvic fractures revealed that, internal fixation of injuries in the posterior and anterior pelvic ring provided excellent or good radiological results in 90% of cases. Additionally, because a reduction with displacement less than or equal to 5 mm was more often associated with a good functional outcome, that should be the goal of operative management. However, the prognosis is also often dependent on associated injuries, particularly a permanent lumbosacral plexus injury. The results favoured internal fixation of all the injured elements of the pelvis for improved stability and a more accurate anatomical result in the entire pelvic ring. The H-shaped sacral fracture with spinopelvic dissociation is a rare injury pattern. Study IV revealed that lumbopelvic fixation was a reliable treatment method. The study also showed that neurological recovery and clinical outcome were associated with the degree of initial translational displacement of the transverse sacral fracture component. Permanent neurological deficits were more frequent and the clinical outcome was worst in completely displaced transverse sacral fractures. An accurate operative reduction of all sacral fracture components was associated with better neurological recovery and clinical outcome. We conclude, that with appropriate treatment of unstable pelvic ring injuries, and associated injuries in other organs, it is possible to achieve better survival rates and functional results, and to reduce long-term disability.Jan Lindahl: LANTIORENKAAN MURTUMIEN HOITO (MANAGEMENT OF PELVIC RING INJURIES) Lantiorenkaan murtumat ovat suhteellisen harvinaisia vammoja käsittäen 1% kaikista sairaalahoitoa vaativista murtumista Suomessa. Epätukevat lantiorenkaan murtumat syntyvät yleensä suuren vammaenergian seurauksena ja niihin liittyy usein muiden kehonosien vammoja. Massiivinen verenvuoto on merkittävin ja usein estettävissä oleva kuolinsyy tylpällä vammamekanismilla syntyneissä lantiorenkaan vammoissa. Mikäli akuuttivaiheen hoito ei ole tehokasta, massiivinen verenvuoto johtaa sydämen ja verenkierron pettämiseen ja potilaan kuolemaan. Tämän väitöskirjatutkimuksen tarkoituksena oli selvittää: 1) ulkoisen tukilaitteen soveltuvuus B- ja C-tyypin lantiorenkaan murtumien lopulliseksi hoitomuodoksi, 2) hengenvaarallisten, runsaasti vuotavien lantionmurtumien alkuvaiheen vuodon tukkimista embolisaation (TAE) avulla ja samalla kartoittaa riskitekijöitä, jotka ennustavat huonoa lopputulosta ja potilaan kuolemaa vaikeimmin vammautuneiden lantionmurtumapotilaiden kohdalla, 3) C-tyypin murtumien kohdalla standardoidun leikkaushoidon ja sisäisen kiinnitysmenetelmän luotettavuutta ja hoidon pitkäaikaistulokset ja 4) ristiluun vaikeimpien ns. H-tyypin murtumien leikkaushoidon luotettavuutta sekä saavutetun asennonkorjauksen, murtumakiinnityksen ja hermorakenteiden vapautuksen pitkäaikaistulokset sekä toipumisennusteeseen vaikuttavat tekijät. Ensimmäisen osajulkaisun tulokset osoittivat, että lantiorenkaan etuosaan kiinnitettävä ulkoinen kiinnityslaite (externi fiksaatiolaite) ei ollut luotettava, eikä sillä voitu taata asianmukaista murtuman paikalleen asettamista ja hyvää lopputulosta vaikeimmissa B- ja C-tyypin murtumissa. Toinen osajulkaisu osoitti, että vuotavien lantionmurtumien kohdalla huonoin ennuste liittyi lantiovammoihin, joissa valtimoiden varjoainekuvauksessa (angiografiassa) todettiin lantion päävaltimon (arteria iliaca interna tai externa) repeämä tai useampia samanaikaisia pienempien valtimosuonten repeämiä. Embolisaatio osoittautui luotettavaksi hoitomenetelmäksi ja kaikki valtimoperäiset vuodot pystyttiin tukkimaan. Kriittisessä vuototilanteessa, jossa angiografiassa todetaan useita vuotokohtia lantion valtimoissa, tulee embolisaatio suorittaa ei-selektiivisesti siten, että lantion aluetta suonittava päävaltimo (arteria iliaca interna) tukitaan välittömästi. Näin vuoto saadaan nopeammin hallintaan ja potilaan selviytymisennuste paranee. C-tyypin lantionmurtumien sisäinen kiinnitysmenetelmä, lantiorenkaan kiinnitys edestä levyin sekä takaa ruuvein tai levyin, osoittautui luotettavaksi (kolmas osajulkaisu). Saavutettu asento säilyi seurannassa erinomaisena tai hyvänä 90%:ssa tapauksista. Leikkauksessa saavutettu murtuman hyvä asento korreloi hyvään neurologiseen toipumiseen ja toiminnalliseen tulokseen. Epäanatominen tulos siten, että murtuman lopullinen siirtymä oli yli 5 mm, ennusti huonompaa toiminnallista lopputulosta. Merkittävin toimintakykyä rajoittava tekijä aiheutui lantion alueen hermopunosvauriosta. Tulokset tukevat käsitystä, jonka mukaan C-tyypin vammoissa tulee korjata ja kiinnittää kaikki murtumat lantiorenkaan etu- ja takaosassa, jolloin saavutetaan parempi anatominen tulos ja samalla parempi lantiorenkaan kokonaistukevuus. Ristiluun H-tyypin murtuma, johon liittyy selkärangan ja lantiorenkaan irtoama toisistaan, on harvinainen lantion takaosan alueen vammakokonaisuus. Neljännessä osajulkaisussa käytetty lannerangan ja lantion välinen kiinnitysmenetelmä (lumbopelvinen kiinnitys) osoittautui luotettavaksi. Lantiohermopunoksen (alaraajojen osittainen halvaus) ja ristiluuhermojen vammat (ns. kauda equina syndrooma) ovat tähän vammatyyppiin liittyen yleisiä. Hermovaurion korjaantuminen ja kokonaistoipumisen ennuste oli riippuvainen ristiluun poikittaisen murtuman siirtymän asteesta. Hermovaurio oli vaikeampiasteinen ja toipumistulos huonompi, mikäli siirtymä ensimmäisessä kuvauksessa oli yli ristiluun paksuuden, kun tuloksia verrattiin siihen potilasryhmään, jolla siirtymä oli osittainen. Hyvä leikkauksessa saavutettu asento kaikissa ristiluun murtumalinjoissa oli yhteydessä parempaan toipumisennusteeseen. Systemaattisella tutkimisella sekä määrätietoisella ja vaikuttavalla hoidolla voidaan vähentää lantiorenkaan murtumiin liittyvää kuolleisuutta, sairastavuutta ja pysyvää vammautumista