Hemodynamic effects of aortic occlusion during hemorrhagic shock

International registry on aortic balloon occlusion in major trauma: Partial inflation does not improve outcomes in abdominal trauma

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a method for temporary hemorrhage control used in haemodynamically unwell patients with severe bleeding. In haemodynamically unwell abdominal trauma patients, laparotomy remains the initial procedure of choice. Using REBOA in patients as a bridge to laparotomy is a novel option whose feasibility and efficacy remain unclear. We aimed to assess the clinical outcome in patients with abdominal injury who underwent both REBOA placement and laparotomy.

METHODS

This is a retrospective study, including trauma patients with an isolated abdominal injury who underwent both REBOA placement and laparotomy, during the period 2011-2019. All data were collected via the Aortic Balloon Occlusion Trauma Registry database.

RESULTS

One hundred and three patients were included in this study. The main mechanism of trauma was blunt injury (62.1%) and the median injury severity score (ISS) was 33 (14-74). Renal failure and multi-organ dysfunction syndrome (MODS) occurred in 15.5% and 35% of patients, respectively. Overall, 30-day mortality was 50.5%. Post balloon inflation systolic blood pressure (SBP) >80 mmHg was associated with lower 24-h mortality (p = 0.007). No differences in mortality were found among patients who underwent partial occlusion vs. total occlusion of the aorta.

CONCLUSIONS

Our results support the feasibility of REBOA use in patients with isolated abdominal injury, with survival rates similar to previous reports for haemodynamically unstable abdominal trauma patients. Post-balloon inflation SBP >80 mmHg was associated with a significant reduction in 24-h mortality rates, but not 30-day mortality. Total aortic occlusion was not associated with increased mortality, MODS, and complication rates compared with partial occlusion.

Approach to traumatic cardiac arrest in the emergency department: a narrative literature review for emergency providers

BACKGROUND

Traumatic cardiac arrest (TCA) is a major contributor to mortality and morbidity in all age groups and poses a significant burden on the healthcare system. Although there have been advances in treatment modalities, survival rates for TCA patients remain low. This narrative literature review critically examines the indications and effectiveness of current therapeutic approaches in treating TCA.

METHODS

We performed a literature search in the PubMed and Scopus databases for studies published before December 31, 2022. The search was refined by combining search terms, examining relevant study references, and restricting publications to the English language. Following the search, 943 articles were retrieved, and two independent reviewers conducted a screening process.

RESULTS

A review of various studies on pre- and intra-arrest prognostic factors showed that survival rates were higher when patients had an initial shockable rhythm. There were conflicting results regarding other prognostic factors, such as witnessed arrest, bystander cardiopulmonary resuscitation (CPR), and the use of prehospital or in-hospital epinephrine. Emergency thoracotomy was found to result in more favorable outcomes in cases of penetrating trauma than in those with blunt trauma. Resuscitative endovascular balloon occlusion of the aorta (REBOA) provides an advantage to emergency thoracotomy in terms of occupational safety for the operator as an alternative in managing hemorrhagic shock. When implemented in the setting of aortic occlusion, emergency thoracotomy and REBOA resulted in comparable mortality rates. Veno-venous extracorporeal life support (V-V ECLS) and veno-arterial extracorporeal life support (V-A ECLS) are viable options for treating respiratory failure and cardiogenic shock, respectively. In the context of traumatic injuries, V-V ECLS has been associated with higher rates of survival to discharge than V-A ECLS.

CONCLUSION

TCA remains a significant challenge for emergency medical services due to its high morbidity and mortality rates. Pre- and intra-arrest prognostic factors can help identify patients who are likely to benefit from aggressive and resource-intensive resuscitation measures. Further research is needed to enhance guidelines for the clinical use of established and emerging therapeutic approaches that can help optimize treatment efficacy and ameliorate survival outcomes.

Traumatic Cardiac Arrest: Scoping Review of Utilization of Resuscitative Endovascular Balloon Occlusion of the Aorta

Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) is increasingly used in trauma resuscitation for patients with life-threatening hemorrhage below the diaphragm and may also be used for patients with traumatic cardiac arrest (TCA). Resuscitative thoracotomy with aortic cross clamping (RT-ACC) maneuver was traditionally performed for patients with TCA due to hemorrhagic shock; however, REBOA has been substituted for RT-ACC in selected TCA cases. During cardiopulmonary resuscitation (CPR) in TCA, REBOA increases cerebral and coronary perfusion, and temporary bleeding control. Both animal and clinical studies have reported the efficacy of REBOA for TCA, and a recent observational study suggested that REBOA may contribute to the return of spontaneous circulation after TCA. Although multiple questions remain unanswered, REBOA has been applied to trauma fields as a novel technology.

Resuscitative thoracotomy

A trauma patient with cardiac tamponade may not survive transfer to the operating theatre for pericardial decompression. This article describes an approach to a resuscitative thoracotomy in the ED, which may be life-saving in these patients when a cardiothoracic surgeon is not immediately available.

Distal organ inflammation and injury after resuscitative endovascular balloon occlusion of the aorta in a porcine model of severe hemorrhagic shock

BACKGROUND AND OBJECTIVE

Resuscitative Endovascular Balloon Occlusion of Aorta (REBOA) has emerged as a potential life-saving maneuver for the management of non-compressible torso hemorrhage in trauma patients. Complete REBOA (cREBOA) is inherently associated with the burden of ischemia reperfusion injury (IRI) and organ dysfunction. However, the distal organ inflammation and its association with organ injury have been little investigated. This study was conducted to assess these adverse effects of cREBOA following massive hemorrhage in swine.

METHODS

Spontaneously breathing and consciously sedated Sinclair pigs were subjected to exponential hemorrhage of 65% total blood volume over 60 minutes. Animals were randomized into 3 groups (n = 7): (1) Positive control (PC) received immediate transfusion of shed blood after hemorrhage, (2) 30min-cREBOA (A30) received Zone 1 cREBOA for 30 minutes, and (3) 60min-cREBOA (A60) given Zone 1 cREBOA for 60 minutes. The A30 and A60 groups were followed by resuscitation with shed blood post-cREBOA and observed for 4h. Metabolic and hemodynamic effects, coagulation parameters, inflammatory and end organ consequences were monitored and assessed.

RESULTS

Compared with 30min-cREBOA, 60min-cREBOA resulted in (1) increased IL-6, TNF-α, and IL-1β in distal organs (kidney, jejunum, and liver) (p < 0.05) and decreased reduced glutathione in kidney and liver (p < 0.05), (2) leukopenia, neutropenia, and coagulopathy (p < 0.05), (3) blood pressure decline (p < 0.05), (4) metabolic acidosis and hyperkalemia (p < 0.05), and (5) histological injury of kidney and jejunum (p < 0.05) as well as higher levels of creatinine, AST, and ALT (p < 0.05).

CONCLUSION

30min-cREBOA seems to be a feasible and effective adjunct in supporting central perfusion during severe hemorrhage. However, prolonged cREBOA (60min) adverse effects such as distal organ inflammation and injury must be taken into serious consideration.

A contemporary assessment of devices for Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA): resource-specific options per level of care

PURPOSE

Use of Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) as adjunct for temporary hemorrhage control in patients with exsanguinating torso hemorrhage is increasing. Characteristics of aortic occlusion balloons (AOB) are diverse and evolving as efforts are made to improve the technology. It is important to select a device that fits the requirements of the medical situation to minimize the risk of failure and complications. The aim of this study is to appraise guidance in the choice of an AOB in a specific situation.

METHODS

We assessed 29 AOB for differences and outline possible advantages and disadvantages of each. Bending stiffness was measured with a three-point bending device.

RESULTS

Diameter of the AOB ranged from 6 (ER-REBOA™) to 10 (Coda^®-46) French. However, some need large-bore access sheaths up to 22 French (Fogarty^®-45 and LeMaitre^®-45) or even insertion via cut-down (Equalizer™-40). Bending stiffness varied from 0.08 N/mm (± 0.008 SD; Coda^®-32) to 0.72 N/mm (± 0.024 SD; Russian prototype). Rescue Balloon™ showed kinking of the shaft at low bending pressures. The only non-compliant AOB is REBOA Balloon^®. ER-REBOA™, Fogarty^®, LeMaitre^®, REBOA Balloon^®, and Rescue Balloon™ are provided with external length marks to assist blind positioning.

CONCLUSION

In resource-limited settings, a guidewire- and fluoroscopy-free, rather stiff device, such as ER-REBOA™, Fogarty^®, and LeMaitre^®, is warranted. Of these devices, ER-REBOA™ is the only catheter compatible with seven French sheaths and specifically designed for emergency hemorrhage control. Of the over-the-wire devices, Q50^® has several features that facilitate use and reduce the risk of malplacement or vessel damage.

Noncompressible Torso Hemorrhage

Noncompressible torso hemorrhage (NCTH) constitutes a leading cause of potentially preventable trauma mortality. NCTH is defined by high-grade injury present in one or more of the following anatomic domains: pulmonary, solid abdominal organ, major vascular or pelvic trauma; plus hemodynamic instability or the need for immediate hemorrhage control. Rapid operative management, as part of a damage control resuscitation strategy, remains the mainstay of treatment. However, endovascular techniques are evolving and may become more mainstream with the advent of hybrid rooms that can deliver concurrent open and radiologic/endovascular management of traumatic hemorrhage.

Implementation of resuscitative endovascular balloon occlusion of the aorta as an alternative to resuscitative thoracotomy for noncompressible truncal hemorrhage

BACKGROUND

Hemorrhage remains the leading cause of death in trauma patients. Proximal aortic occlusion, usually performed by direct aortic cross-clamping via thoracotomy, can provide temporary hemodynamic stability, permitting definitive injury repair. Resuscitative endovascular balloon occlusion of the aorta (REBOA) uses a minimally invasive, transfemoral balloon catheter, which is rapidly inserted retrograde and inflated for aortic occlusion, and may control inflow and allow time for hemostasis. We compared resuscitative thoracotomy with aortic cross-clamping (RT) with REBOA in trauma patients in profound hemorrhagic shock.

METHODS

Trauma registry data was used to compare all patients undergoing RT or REBOA during an 18-month period from two Level 1 trauma centers.

RESULTS

There was no difference between RT (n = 72) and REBOA groups (n = 24) in terms of demographics, mechanism of injury, or Injury Severity Scores (ISSs). There was no difference in chest and abdominal Abbreviated Injury Scale (AIS) scores between the groups. However, the RT patients had lower extremity AIS score as compared with REBOA patients (1.5 [0-3] vs. 4 [3-4], p < 0.001). Of the 72 RT patients, 45 (62.5%) died in the emergency department, 6 (8.3%) died in the operating room, and 14 (19.4%) died in the intensive care unit. Of the 24 REBOA patients, 4 (16.6%) died in the emergency department, 3 (12.5%) died in the operating room, and 8 (33.3%) died in the intensive care unit. In comparing location of death between the RT and REBOA groups, there were a significantly higher number of deaths in the emergency department among the RT patients as compared with the REBOA patients (62.5% vs. 16.7%, p < 0.001). REBOA had fewer early deaths and improved overall survival as compared with RT (37.5% vs. 9.7%, p = 0.003).

CONCLUSION

REBOA is feasible and controls noncompressible truncal hemorrhage in trauma patients in profound shock. Patients undergoing REBOA have improved overall survival and fewer early deaths as compared with patients undergoing RT.

LEVEL OF EVIDENCE

Therapeutic study, level IV.

Treatment of intra-abdominal haemorrhagic shock by Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA)

PURPOSE

Haemorrhagic shock is commonly encountered in the emergency room and is associated with high morbidity and mortality. For intra-thoracic and intra-abdominal bleeding, treatment usually requires either surgery or an interventional radiologic procedure. Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) has already been described for pelvic fractures and intra-abdominal haemorrhages. In this case report, we present the use of REBOA in a patient admitted for haemorrhagic shock due to a ruptured splenic artery aneurysm.

CASE REPORT

We describe the case of a 35-year-old male with suspected massive pulmonary embolism. Prior to diagnostic confirmation by CT-scan, the patient suffered several cardiac arrests. CT-scan revealed a massive haemoperitoneum secondary to a ruptured aneurysm of the splenic artery. Because of refractory hypotension despite maximal conventional therapy, we used REBOA before patient transfer to the operating room for splenectomy.

CONCLUSIONS

This case underlines the feasibility of REBOA and discusses its role in uncontrollable intra-abdominal haemorrhagic shock.

Western Trauma Association critical decisions in trauma: resuscitative thoracotomy

BACKGROUND

In the past three decades, there has been a significant clinical shift in the performance of resuscitative thoracotomy (RT), from a nearly obligatory procedure before declaring any trauma patient deceased to a more selective application of RT. We have sought to formulate an evidence-based guideline for the current indications for RT after injury in the patient.

METHODS

The Western Trauma Association Critical Decisions Committee queried the literature for studies defining the appropriate role of RT in the trauma patient. When good data were not available, the Committee relied on expert opinion.

RESULTS

There are no published PRCT and it is not likely that there will be; recommendations are based on published prospective observational and retrospective studies, as well as expert opinion of Western Trauma Association members. Patients undergoing cardiopulmonary resuscitation (CPR) on arrival to the hospital should be stratified based on injury and transport time. Indications for RT include the following: blunt trauma patients with less than 10 minutes of prehospital CPR, penetrating torso trauma patients with less than 15 minutes of CPR, patients with penetrating trauma to the neck or extremity with less than 5 minutes of prehospital CPR, and patients in profound refractory shock. After RT, the patient's intrinsic cardiac activity is evaluated; patients in asystole without cardiac tamponade are declared dead. Patients with a cardiac wound, tamponade, and associated asystole are aggressively treated. Patients with an intrinsic rhythm following RT should be treated according to underlying primary pathology. Following several minutes of such treatment as well as generalized resuscitation, salvageability is reassessed; we define this as the patient's ability to generate a systolic blood pressure of greater than 70 mm Hg with an aortic cross-clamp if necessary.

CONCLUSION

The success of RT approximates 35% for the patient arriving in shock with a penetrating cardiac wound and 15% for all patients with penetrating wounds. Conversely, patient outcome is relatively poor when RT is performed for blunt trauma, 2% survival for patients in shock and less than 1% survival for patients with no vital signs. Patients undergoing CPR on arrival to the hospital should be stratified based on injury and transport time to determine the utility of RT. This algorithm represents a rational approach that could be followed at trauma centers with the appropriate resources; it may not be applicable at all hospitals caring for the injured. There will be patient, personnel, institutional, and situational factors that may warrant deviation from the recommended guideline. The annotated algorithm is intended to serve as a quick bedside reference for clinicians.

Physiologic tolerance of descending thoracic aortic balloon occlusion in a swine model of hemorrhagic shock

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an emerging technique in trauma; however, the physiologic sequelae have not been well quantified. The objectives of this study were to characterize the burden of reperfusion and organ dysfunction of REBOA incurred during 30 or 90 min of class IV shock in a survivable porcine model of hemorrhage.

METHODS

After induction of shock, animals were randomized into 4 groups (n = 6): 30 min of shock alone (30-Shock) or with REBOA (30-REBOA) and 90 min of shock alone (90-Shock) or with REBOA (90-REBOA). Cardiovascular homeostasis was then restored with blood, fluid, and vasopressors for 48 h. Outcomes included mean central aortic pressure (MCAP), lactate concentration, organ dysfunction, histologic evaluation, and resuscitation requirements.

RESULTS

Both REBOA groups had greater MCAPs throughout their shock phase compared to controls (P < .05) but accumulated a significantly greater serum lactate burden, which returned to control levels by 150 min in the 30-REBOA groups and 320 min in the 90-REBOA group. There was a greater level of renal dysfunction and evidence of liver necrosis seen in the 90-REBOA group compared to the 90-Shock group. There was no evidence of cerebral or spinal cord necrosis in any group. The 90-REBOA group required more fluid resuscitation than the 90-Shock group (P = .05).

CONCLUSION

REBOA in shock improves MCAP and is associated with a greater lactate burden; however, this lactate burden returned to control levels within the study period. Ultimately, prolonged REBOA is a survivable and potentially life-saving intervention in the setting of hemorrhagic shock and cardiovascular collapse in the pig.

The use of emergency department thoracotomy for traumatic cardiopulmonary arrest

Despite the establishment of evidence-based guidelines for the resuscitation of critically injured patients who have sustained cardiopulmonary arrest, rapid decisions regarding patient salvageability in these situations remain difficult even for experienced physicians. Regardless, survival is limited after traumatic cardiopulmonary arrest. One applicable, well-described resuscitative technique is the emergency department thoracotomy-a procedure that, when applied correctly, is effective in saving small but significant numbers of critically injured patients. By understanding the indications, technical details, and predictors of survival along with the inherent risks and costs of emergency department thoracotomy, the physician is better equipped to make rapid futile versus salvageable decisions for this most severely injured subset of patients.

Direct vascular control results in less physiologic derangement than proximal aortic clamping in a porcine model of noncompressible extrathoracic torso hemorrhage

BACKGROUND

The optimal method of vascular control and resuscitation in patients with life-threatening, extrathoracic torso hemorrhage remains debated. Guidelines recommend emergency department thoracotomy (EDT) with aortic clamping, although transabdominal aortic clamping followed by vascular control and direct vascular control (DVC) without aortic clamping are alternatives. The objective of this study is to compare the effectiveness of three approaches to extrathoracic torso hemorrhage in a large animal model.

METHODS

Adolescent swine (Sus Scrofa) (mean weight = 80.9 kg) were randomized into three groups all of which had class IV shock established by hemorrhage from an iliac artery injury. Group 1: EDT with thoracic aortic clamping (N = 6); group 2: transabdominal supraceliac aortic clamping (SCC; N = 6); and group 3: DVC of bleeding site without aortic clamping (N = 6). After hemorrhage, EDT or SCC was performed in groups 1 and 2, respectively, with subsequent exploration of the bleeding site and placement of a temporary vascular shunt (TVS). Group 3 (DVC) underwent direct exploration of the injury and placement of a TVS. All groups were resuscitated to predefined physiologic endpoints over 6 hours with repeated measures of central and cerebral perfusion and end-organ function at standardized time points. Postmortem tissue analysis was performed to quantify injury to critical tissue beds.

RESULTS

There was no difference in mortality among the groups and no TVS failures. Central aortic pressure, carotid flow, and partial pressure brain tissue oximetry, all demonstrated increases in EDT and SCC after application of the aortic clamp relative to DVC (p < 0.05). During resuscitation, serum lactate levels were higher in EDT compared with SCC and DVC (6.85 vs. 3.08 and 2.15, respectively; p < 0.05) and serum pH in EDT reflected greater acidosis than SCC and DVC (7.24 vs. 7.36 and 7.39, respectively; p < 0.05). EDT and SCC required more intravenous fluid than DVC (2,166 mL and 2,166 mL vs. 667 mL, respectively; p < 0.05) and more vasopressors were used in EDT and SCC compared with DVC (52.1 μg and 43.5 μg vs. 12.4 μg, respectively; p < 0.05). Brain and myocardial tissue stains demonstrated the same degree of acute ischemic changes in all groups.

CONCLUSION

Although aortic clamping increases central and cerebral perfusion, DVC results in less physiologic derangement. The optimal method of aortic control would incorporate the benefits of maintained central pressure with less associated morbidity. Clinical studies evaluating DVC are warranted.

Emergency department thoracotomy: still useful after abdominal exsanguination?

BACKGROUND

Although literature regarding emergency department thoracotomy (EDT) outcome after abdominal exsanguination is limited, numerous reports have documented poor EDT survival in patients with anatomic injuries other than cardiac wounds. As a result, many trauma surgeons consider prelaparotomy EDT futile for patients dying from intra-abdominal hemorrhage. Our primary study objective was to prove that prelaparotomy EDT is beneficial to patients with exsanguinating abdominal hemorrhage.

METHODS

A retrospective review of 237 consecutive EDTs for penetrating injury (2000-2006) revealed 50 patients who underwent EDT for abdominal exsanguination. Age, gender, injury mechanism and location, field and emergency department (ED) signs of life, prehospital time, initial ED cardiac rhythm, vital signs, Glasgow Coma Score, blood transfusion requirements, predicted mortality, primary abdominal injuries, and the need for temporary abdominal closure were analyzed. The primary study endpoint was neurologically intact hospital survival.

RESULTS

The 50 patients who underwent prelaparotomy EDT for abdominal exsanguination were largely young (mean, 27.3 +/- 8.2 years) males (94%) suffering firearm injuries (98%). Patients presented with field (84%) and ED signs of life (78%) after a mean prehospital time of 21.2 +/- 9.8 minutes. Initial ED cardiac rhythms were variable and Glasgow Coma Score was depressed (mean, 4.2 +/- 3.2). Eight (16%) patients survived hospitalization, neurologically intact. Of these eight, all were in hemorrhagic shock because of major abdominal vascular (75%) or severe liver injuries (25%) and all required massive blood transfusion (mean, 28.6 +/- 17.3 units) and extended intensive care unit length of stay (mean, 36.3 +/- 25.7 days).

CONCLUSIONS

Despite critical injuries, 16% survived hospitalization, neurologically intact, after EDT for abdominal exsanguination. Our results suggest that prelaparotomy EDT provides survival benefit to penetrating trauma victims dying from intra-abdominal hemorrhage.

Emergency department thoracotomy for the critically injured patient: Objectives, indications, and outcomes

In the past three decades there has been a significant clinical shift in the performance of emergency department thoracotomy (EDT), from a nearly obligatory procedure before declaring any trauma patient to select patients undergoing EDT. The value of EDT in resuscitation of the patient in profound shock but not yet dead is unquestionable. Its indiscriminate use, however, renders it a low-yield and high-cost procedure. Overall analysis of the available literature indicates that the success of EDT approximates 35% in the patient arriving in shock with a penetrating cardiac wound, and 15% for all penetrating wounds. Conversely, patient outcome is relatively poor when EDT is done for blunt trauma; 2% survival in patients in shock and less than 1% survival with no vital signs. Patients undergoing CPR upon arrival to the emergency department should be stratified based upon injury and transport time to determine the utility of EDT. The optimal application of EDT requires a thorough understanding of its physiologic objectives, technical maneuvers, and the cardiovascular and metabolic consequences.

Hemodynamic effects of aortic occlusion during hemorrhagic shock and cardiac arrest

OBJECTIVE

To determine the hemodynamic consequences of aortic occlusion during controlled hemorrhagic arrest.

METHODS

Ten anesthetized, hemodynamically monitored swine were subjected to a 40 mL/kg hemorrhage over 10 minutes, followed by a 5-minute period of apnea. At this time (T15), they were randomized into an UP group (n = 5) in which the thoracic aorta was occluded or a DOWN group (n = 5) in which the aorta was not occluded. Simultaneously, volume resuscitation with shed blood plus 20 mL/kg of normal saline was performed over a 10-minute period. Cardiac massage was performed until return of spontaneous circulation (ROSC), which was defined as a sustained systolic blood pressure > 60 mm Hg. After 30 minutes of occlusion (T45), the aortic occlusion was released. Parameters measured include mixed venous and arterial blood gases, serum lactic acid levels, cardiac index, mean arterial pressure (MAP), mean pulmonary artery pressure (MPAP), coronary perfusion pressure (CoPP), and left ventricular stroke work index (LVSWI). Oxygen delivery index (DO2I) was measured using a pulmonary artery catheter, and oxygen consumption index (VO2I) was measured by direct calorimetry (Delta Trac metabolic monitor).

RESULTS

Four animals in each group achieved ROSC after 3.0 +/- 1.8 and 2.2 +/- 1.8 minutes in the occluded and nonoccluded groups, respectively. During cardiac compressions and volume resuscitation, the CoPP, MAP, and MPAP were greater in the UP group, although the differences did not achieve statistical significance. After volume resuscitation was complete and during the period of aortic occlusion (T25-T45), the UP group had significantly greater MAP (mm Hg), with a difference of 42.5 +/- 20.75 mm Hg at T25 and 44.7 +/- 19 mm Hg at T35 (p < 0.03). Despite no difference in DO2I, VO2I (mL/min/kg) was significantly lower in the UP group than in the DOWN group, 4.28 +/- 0.48 versus 8.33 +/- 0.85 at T25 (p = 0.0002) and 4.62 +/- 0.9 versus 7.09 +/- 0.72 at T35 (p = 0.0005). After release of aortic occlusion at T45, the UP group had significantly lower CoPP (mm Hg) than the DOWN group (20.5 +/- 17.3 versus 66.5 +/- 28.2 at T45, p = 0.03). LVSWI (g/kg) was also lower in the UP than in the DOWN group (18.6 +/- 8.28 versus 36.5 +/- 10.2 at T60 [p = 0.031 and 23.6 +/- 6.48 versus 48.8 +/- 15.3 at T240 [p = 0.021). After release of the occlusion, there were trends toward increased acidosis and lactic acid levels in the UP group.

CONCLUSIONS

Aortic occlusion in this controlled hemorrhagic arrest model does not result in improved salvage but is associated with impaired left ventricular function, systemic oxygen utilization, and coronary perfusion pressure in the postresuscitation period.

Emergency thoracotomy

There continues to be a debate on the indications for and value of the emergency department thoracotomy, especially with regard to the subject of thoracotomy performed by the emergency physician. The current literature does not deal specifically with thoracotomies performed in the emergency department by an emergency physician on trauma patients. This article describes a technique for emergency department thoracotomy that can be performed by an emergency physician.

Emergency department thoracotomy for traumatic cardiac arrest

There continues to be a debate on the indications for and value of emergency department thoracotomy, especially with regard to thoracotomies performed by emergency physicians. The current literature does not deal specifically with thoracotomies performed by an emergency physician on trauma patients in full cardiopulmonary arrest in a setting with no immediate surgical backup. This paper reports the results of 6 years of experience by one emergency physician in such a setting involving 80 patients, with a 6% overall survival rate, including two patients who survived blunt traumatic cardiac arrests. This lends support to emergency-physician-performed thoracotomies on trauma patients in "extremis," even in the setting of a hospital with no immediate surgical backup.

Emergency department thoracotomy for trauma: a collective review

A decade of experience with resuscitative thoracotomy for the trauma victim in extremis has been gained since the pioneering efforts of Mattox and his associates in 1974. It appears, from a review of the various reports from different trauma centers, that there is an emergence of a consensus as to the best indications for the procedure. It is generally agreed upon that ERT is fruitless in the patient with severe head trauma or when vital signs were absent at the scene of the injury. In the absence of penetrating thoracic injuries ERT yields a very poor survival in patients without vital signs on admission to the emergency center. It is widely accepted that the best results for ERT are in patients with cardiac tamponade. The prognosis is hopeless in patients without vital signs after sustaining blunt trauma.

Aortic compressor for aortic occlusion in hemorrhagic shock

The aortic compressor is a device that allows rapid, simple, immediately reversible occlusion of the thoracic aorta, without the aortic dissection required to use an aortic cross-clamp. We evaluated the aortic compressor in a controlled study using a canine hemorrhagic shock model. Twelve mongrel dogs were exsanguinated to a mean arterial pressure (MAP) of 47 mm Hg and maintained at that level for 20 minutes. At that point, all animals had a left lateral thoracotomy. Six study animals had the thoracic aorta occluded at the diaphragm using the compressor. Five minutes after thoracotomy, with or without occlusion, the shed blood was reinfused. Application of the aortic compressor was the only variable. Use of the aortic compressor led to an immediate and statistically significant doubling of the study animals' MAP. The increased afterload of aortic occlusion did not impair cardiac output. The cardiac index of the study animals rose slightly, while that of the control animals fell. At the same time the compressor prevented blood flow to the abdominal aorta. If the canine model can be extrapolated to human application, then the aortic compressor would be expected to enhance perfusion of the heart and brain during hemorrhagic shock, prevent further arterial blood loss from intra-abdominal injury or ruptured abdominal aortic aneurysm, and preserve already diminished cardiac output. Because the aorta does not need to be dissected out to use the compressor, there is no risk of injury to nearby vascular structures.