A case of fatal fulminant fat embolism syndrome saved by VA-ECMO in the acute phase of multiple trauma.

Fat embolism syndrome (FES) is a rare complication of long bone fractures, with fulminant FES developing within 12 h of injury and often proving fatal (Shaikh, 2009 [1]). Here, we present a case of fulminant FES in a patient who developed sudden right heart failure after undergoing external fixation of a lower leg fracture and required veno-arterial extracorporeal membrane oxygenation (VA-ECMO). A 79-year-old woman injured in a traffic accident was transferred to our emergency department. Upon arrival, her level of consciousness deteriorated, and she developed circulatory failure. We promptly performed transcatheter arterial embolization for the pelvic fracture and external fixation of the tibiofibular fracture. Within four hours of the injury, she was admitted to our intensive care unit (ICU). Two hours after ICU admission, her hemodynamic status worsened, necessitating the administration of maximum catecholamine dose. Echocardiography revealed petechial hemorrhage of the palpebral conjunctiva and enlargement of the right ventricle. Despite maximal supportive care, the patient remained cardiovascularly unstable. Therefore, VA-ECMO was initiated to stabilize her hemodynamic status. Thereafter, her hemodynamics stabilized, and ECMO support was weaned off and removed on day 3. Subsequent magnetic resonance imaging revealed evidence of cerebral fat embolism. On day 9, she underwent open reduction of the left lower leg with internal fixation and was transferred to another hospital on day 29. This report documents the successful management of fulminant FES during the acute phase of multiple traumas. Clinicians should consider VA-ECMO when suspecting uncontrolled circulatory failure due to fulminant FES, even in the acute phase of multiple trauma.

PCO2 on arrival as a predictive biomarker in patients with out-of-hospital cardiac arrest.

BACKGROUND: Treating patients with out-of-hospital cardiac arrest (OHCA) requires early prediction of outcome, ideally on hospital arrival, as it can inform the clinical decisions involved. This study evaluated whether partial pressure of carbon dioxide (PCO2) on arrival is associated with outcome at one month OHCA patients. METHODS: This was a single-center retrospective study of adult OHCA patients treated between January 2016 and December 2020. Outcomes were defined along the Cerebral Performance Category (CPC) scale. Primary outcome was mortality (CPC 5) at one month. Secondary outcomes were death or unfavorable neurological outcome (CPC 3-5) and unfavorable neurological outcome (CPC 3-4) at one month. Multivariable analysis was adjusted for age, sex, witnessed cardiac arrest, bystander cardiopulmonary resuscitation, initial shockable rhythm, and time from call to emergency medical services to hospital arrival. RESULTS: Out of 977 OHCA patients in the study period, 19 were excluded because they were aged under 18 years, 79 because they underwent extracorporeal cardiopulmonary resuscitation, and 101 due to lack of PCO2 data. This study included 778 patients total; mortality (CPC 5) at one month was observed in 706 (90.7%), death or unfavorable neurological outcome (CPC 3-5) in 743 (95.5%), and unfavorable neurological outcome (CPC 3-4) in 37 (4.8%). In multivariable analysis, high PCO2 levels showed significant association with mortality (CPC 5) at one month (odds ratio [OR] [per 5 mmHg], 1.14; 95% confidence interval [CI], 1.08-1.21), death or unfavorable neurological outcome (CPC 3-5) (OR [per 5 mmHg], 1.29; 95% CI, 1.17-1.42), and unfavorable neurological outcome (CPC 3-4) (OR [per 5 mmHg], 1.21; 95% CI, 1.04-1.41). CONCLUSIONS: High PCO2 on arrival was significantly associated with mortality and unfavorable neurological outcome in OHCA patients.

Long-term outcomes and prognostic factors of extracorporeal cardiopulmonary resuscitation in patients older than 75 years: a single-centre retrospective study.

BACKGROUND: Few studies have assessed older adult patients who received extracorporeal cardiopulmonary resuscitation (ECPR) after cardiac arrest, and outcomes and prognostic factors of ECPR in this population remain unclear. This study aimed to assess the long-term outcomes and prognostic factors among patients older than 75 years who received ECPR after experiencing cardiac arrest. METHODS: This is a single-centre, retrospective case-control study conducted between August 2010 and July 2019. Consecutive patients older than 75 years who had in-hospital (IHCA) or out-of-hospital cardiac arrest (OHCA) and received ECPR at the Emergency Department in the Hyogo Emergency Medical Center, Hyogo, Japan, were included. The primary outcome was a favourable neurological outcome, defined as a Cerebral Performance Category score of 1-2 at 1 year after the event. Univariate logistic regression was used to determine the association between variables and patient outcomes. RESULTS: Of the 187 patients with cardiac arrest who received ECPR, 30 were older than 75 years and 28 (15% of the cohort receiving ECPR) were examined in this study. The median age of the patients was 79 years (IQR 77-82), and there were 13 (46%) male patients. Neurological outcomes were favourable for seven (25%) patients, five of whom had IHCA and two with out-of-hospital OHCA. On univariate analysis, patients with a favourable outcome had a shorter median total collapse time (TCT) than those with an unfavourable outcome (favourable: 18.0 min (IQR 13.0-33.5) vs unfavourable: 44.0 min (IQR 25.0-53.0); p=0.049). CONCLUSION: In selected patients older than 75 years, ECPR could be beneficial by providing a shorter TCT, which may contribute to favourable neurological outcomes. Nevertheless, further studies are needed to validate these findings.

Association between stress hyperglycemia on admission and unfavorable neurological outcome in OHCA patients receiving ECPR.

BACKGROUND: Stress hyperglycemia is a normal response to stress and has been associated with outcomes in out-of-hospital cardiac arrest (OHCA) patients. However, this association remained unknown in OHCA patients receiving extracorporeal cardiopulmonary resuscitation (ECPR). This study aimed to examine the association between degree of stress hyperglycemia on admission and neurological outcomes at discharge in OHCA patients receiving ECPR. PATIENTS AND METHODS: This was a retrospective cohort study of adult OHCA patients receiving ECPR between 2011 and 2021. Patients were classified into three groups: absence of stress hyperglycemia (blood glucose level on admission < 200 mg/dL), moderate stress hyperglycemia (200-299 mg/dL), and severe stress hyperglycemia (≥ 300 mg/dL). The primary outcome was unfavorable neurological outcome (Cerebral Performance Category: 3-5) at discharge. RESULTS: This study included 160 patients; unfavorable neurological outcomes totaled 79.4% (n = 127). There were 23, 52, and 85 patients in the absence, moderate, and severe stress hyperglycemia groups, respectively. Of each group, unfavorable neurological outcomes constituted 91.3%, 71.2%, and 81.2%, respectively. Multivariable analysis showed that, compared with moderate stress hyperglycemia, absence of stress hyperglycemia on admission was significantly associated with unfavorable neurological outcome at discharge (odds ratio [OR], 4.70; 95% confidence interval [CI], 1.07-33.35; p = 0.039). CONCLUSION: Compared with moderate stress hyperglycemia on admission, absence of stress hyperglycemia showed significant association with unfavorable neurological outcome at discharge in OHCA patients receiving ECPR.

Holospinal epidural abscess caused by Streptococcus anginosus group: a literature review.

Spinal epidural abscess (SEA) usually extends over three to four vertebrae. We present a case of holospinal epidural abscess (HEA) caused by the Streptococcus anginosus group (SAG). A man in his 40s with a 2-week history of fever, back pain, and progressive tetraparesis was referred to us from the local hospital. MRI showed epidural fluid collection from C2 to S1. Blood and pus cultures revealed the presence of SAG. He was treated by emergency laminoplasty, epidural drainage and antibiotic treatment. After the 111st hospital day, his manual muscle test was shown to improve; hence, he was transferred for rehabilitation. According to the previous reports, we identified 12 cases of SEA extending from the cervical spine to the sacrum, including our case. For one-fourth of these cases, SAG was the causative organism of this rare SEA. Therefore, SAG should be considered causative organisms in HEA.

A case of cardiac impalement injury with severe shock treated surgically after diagnosis using computed tomography and managed via extracorporeal membrane oxygenation in the hybrid emergency room.

The Hybrid Emergency Room System (HERS) allows clinicians to perform life-saving procedures without having to transfer patients. Several studies have reported the effectiveness of the HERS in the treatment of blunt trauma patients. However, the use of a hybrid emergency room (ER) for the treatment of penetrating cardiac injuries, including impalement injuries, has not been reported. We present the case of a patient with cardiac impalement injury that was diagnosed via computed tomography (CT) and was managed via extracorporeal membrane oxygenation (ECMO) in the hybrid ER and via surgery in the operating room. A 55-year-old man was transferred to our hybrid ER due to a penetrating wood injury through the right thoracic region. The patient had unstable vital signs. A CT scan revealed a pericardial effusion, right lung contusion, and bilateral pneumothoraxes. There were no signs of hemothorax or aortic injury. Veno-arterial-ECMO was performed in preparation for surgery. The patient was then transferred to the operating room. Pericardiotomy and cardiac repair were performed, and the ECMO was discontinued postoperatively. The patient was discharged on postoperative day 10 without complications. The hybrid ER allows rapid CT examination without relocation. Thus, it facilitates the formation of a timely and effective treatment plan. This report documents the successful management of a cardiac impalement injury in the HERS.

A novel extracorporeal cardiopulmonary resuscitation strategy using a hybrid emergency room for patients with pulseless electrical activity.

BACKGROUND: Whether extracorporeal cardiopulmonary resuscitation (ECPR) is indicated for patients with pulseless electrical activity (PEA) remains unclear. Pulmonary embolism with PEA is a good candidate for ECPR; however, PEA can sometimes include an aortic disease and intracranial haemorrhage, with extremely poor neurological outcomes, and can thus not be used as a suitable candidate. We began employing an ECPR strategy that utilised a hybrid emergency room (ER) to perform computed tomography (CT) before extracorporeal membrane oxygenation (ECMO) induction from January 2020. Therefore, the present study aimed to evaluate the effectiveness of this ECPR strategy. METHODS: Medical records of patients who transferred to our hybrid ER and required ECPR for PEA between January 2020 and November 2021 were reviewed. RESULTS: Twelve consecutive patients (median age, 67 [range, 57-73] years) with PEA requiring ECPR were identified in our hybrid ER. Among these patients, nine were diagnosed using an initial CT scan (intracranial haemorrhage (3); cardiac tamponade due to aortic dissection (3); aortic rupture (2); and cardiac rupture (1)), and unnecessary ECMO was avoided. The remaining three patients underwent ECPR, and two of them survived with favourable neurological outcomes. Patients not indicated for ECPR were excluded before ECMO induction. CONCLUSION: Our ECPR strategy that involved the utilisation of a hybrid ER may be useful for the exclusion of patients with PEA not indicated for ECPR and decision making.

Treatment of a gunshot wound (birdshot) patient with traumatic shock in a hybrid emergency room.

Background: Although the Hybrid Emergency Room System (HERS) is a relatively novel method for treating severe trauma patients, there have been few reported cases of gunshot wound patients treated in HERS. Here we report our treatment of a unique gunshot wound case, with shock, in a HERS setting. Case presentation: A 72-year-old male was transferred to our hospital due to a gunshot wound (GSW). He presented with left chest injuries and vital signs consistent with shock. While resuscitating the patient, including massive blood transfusion and surgery to control the damage, a subsequent computed tomography in HERS revealed the internal distribution of the birdshot and damage to the abdominal organs. Lower lobectomy of the left lung and laparotomy for gastrointestinal repair were performed. After a planned repeat operation and reconstruction of the left chest wall, he was discharged uneventfully. Conclusions: HERS during resuscitation was useful for helping clinicians not only to find the bullets' distribution and judge the severity of injury caused by the gunshot, but also to develop subsequent therapeutic strategies for rescuing the gunshot wound patient from a life-threatening situation.

Successful interhospital transfer for extracorporeal cardiopulmonary resuscitation of a patient who had a cardiac arrest after cesarean section.

BACKGROUND: Studies describing the effectiveness of extracorporeal cardiopulmonary resuscitation (ECPR) for peripartum cardiopulmonary arrest are lacking. CASE PRESENTATION: A 39-year-old woman underwent elective cesarean section. Right after surgery, she fell into a cardiac arrest and was promptly transferred to our institute by ambulance. On arrival, we immediately initiated ECPR, within 63 min of the cardiac arrest. Return of spontaneous circulation was achieved 80 min after induction of extracorporeal membrane oxygenation. As the hemodynamics of the patient stabilized, extracorporeal membrane oxygenation was discontinued on day 3 of hospitalization. The patient's cerebral performance category score was 3 at discharge, which improved to 2 after 3 months. CONCLUSION: This case suggests that prompt interhospital transfer and ECPR might be effective for peripartum cardiac arrest due to nonhemorrhagic events.

Association Between Converting Asystole From Initial Shockable ECG Rhythm Before Extracorporeal Cardiopulmonary Resuscitation and Outcome.

BACKGROUND: Initial electrocardiogram (ECG) rhythm is a predictor of outcomes in out-of-hospital cardiac arrest (OHCA) in patients receiving extracorporeal cardiopulmonary resuscitation (ECPR). However, ECG rhythm often changes before ECPR, and the consequence of this change remains unclear. This study aimed to assess the relationship between the conversion of ECG rhythm from initial shockable rhythm before ECPR and mortality. PATIENTS AND METHODS: This was a retrospective cohort study of OHCA patients with initial shockable rhythm who underwent ECPR between January 2010 and September 2020. Patients were classified into two groups: asystole (patients whose ECG rhythm converted to asystole at any time before initiating ECPR) and non-asystole (patients whose ECG rhythm did not convert to asystole at any time before initiating ECPR) groups. The primary outcome was in-hospital mortality. RESULTS: A total of 102 patients were included in the study; in-hospital mortality rate was 46.1% (n = 47) and 76 (74.5%) patients had unfavorable neurological outcomes (Cerebral Performance Category: 3-5). There were 33 and 69 patients in the asystole and non-asystole groups, respectively. The mortality rates in the asystole and non-asystole groups were 69.7% and 34.8%, respectively (P = 0.001). On multivariable analysis, the asystole group showed a significant association with mortality (odds ratio, 5.42; 95% confidence interval, 2.11-15.36; P < 0.001). CONCLUSION: Conversion to asystole before ECPR at any time in patients with OHCA is associated with mortality in patients with an initial shockable ECG rhythm.

Prehospital management of a non-intubated inhalation injury patient using transcutaneous monitoring of carbon dioxide.

A 46-year-old man experienced facial burns due to a fire in his house. In the prehospital setting, suspecting inhalation injury and carbon monoxide poisoning, an emergency physician decided to bring him to the hospital for carbon dioxide (CO2) monitoring without endotracheal intubation for approximately 20 min because of less severe respiratory distress. On the way to the hospital, the patient's end-tidal CO2 monitoring ranged from 19 to 30 mm Hg, and transcutaneous carbon dioxide (TcPCO2) remained between 50 and 55 mm Hg. On arrival at the hospital, PaCO2 showed 51.6 mm Hg. Endotracheal intubation using a bronchoscope was performed in the emergency room, and inhalation injury was observed. He was extubated on day 5 and discharged on day 10. In the prehospital setting, TcPCO2 monitoring is useful for initial management of non-intubated inhalation injury patients even with high concentration oxygen.

Retro-odontoid pseudotumor with uncommon presentation of cervical spine injury.

BACKGROUND: We report the first case of retro-odontoid pseudotumor with an isolated symptom of C2-C3 dysesthesia triggered by a traumatic event. CASE PRESENTATION: An 86-year-old man, who was a wood craftsman for more than 50 years, presented to the emergency room with sudden-onset severe posterior head and neck dysesthesia after accidentally falling backward. No neurological impairment of the extremities was noted. Computed tomography revealed a C2-C7 osteophyte formation, mainly in front of the vertebral bodies. Moreover, magnetic resonance imaging showed cervical spinal cord compression by a soft tissue mass posterior to the odontoid process of the axis. Therefore, we diagnosed a cervical spine injury with an isolated symptom of C2-C3 dysesthesia due to a retro-odontoid pseudotumor. He did not undergo surgical intervention and was transferred to a rehabilitation hospital on day 11 for pain control. CONCLUSION: Our report could be useful to emergency physicians dealing with similar cases of cervical symptoms following trauma.

Pitfall of left sided triple-lumen catheter for continuous renal replacement therapy: A case report.

We report a case of vascular injury caused by a multi-lumen catheter for CRRT inserted through left jugular vein. Diagnosis was delayed because CRRT could be continued. Clinicians should be aware of potential vascular complications associated with the wrong placement of multi-lumen catheters even if blood flow continues without difficulty.

JAAM Nationwide Survey on the response to the first wave of COVID-19 in Japan. Part I: How to set up a treatment system in each hospital.

AIM: To clarify how the medical institutions overcame the first wave of coronavirus disease 2019 (COVID-19) in Japan and to discuss its impact on the medical labor force. METHODS: We analyzed questionnaire data from the end of May 2020 from 180 hospitals (102,578 beds) certified by the Japanese Association for Acute Medicine. RESULTS: Acute (emergency) medicine physicians treated severe COVID-19 patients in more than half of hospitals. Emergency medical teams consisted of acute medicine physicians and other specialists. Frontline acute care physicians were concerned about their risk of infection in 80% of hospitals, and experienced stress due to a lack of personal protective equipment. Twenty-six of the 143 hospitals that had a mental health check/consultation system in place indicated that there was a doctor who experienced mental health problems. Of the 37 hospitals without a system, only one hospital was aware of the presence of a doctor complaining of mental health problems. CONCLUSION: Acute care physicians and physicians in other departments experienced high levels of stress as they fought to arrange COVID-19 treatment teams and inpatient COVID-19 wards for infected patients. Medical materials and equipment may be sufficient for a second or third wave; however, active support is needed for the physical and mental care of medical staff. Mental health problems may be missed in facilities without mental check and consultation system.

JAAM nationwide survey on the response to the first wave of COVID-19 in Japan. Part II: how did medical institutions overcome the first wave and how should they prepare for the future?

Aim: To investigate and clarify the surge capacity of staff/equipment/space, and patient outcome in the first wave of coronavirus disease (COVID-19) in Japan. Methods: We analyzed questionnaire data from the end of May 2020 from 180 hospitals (total of 102,578 beds) with acute medical centers. Results: A total of 4,938 hospitalized patients with COVID-19 were confirmed. Of 1,100 severe COVID-19 inpatients, 112 remained hospitalized and 138 died. There were 4,852 patients presumed to be severe COVID-19 patients who were confirmed later to be not infected. Twenty-seven hospitals (15% of 180 hospitals) converted their intensive care unit (ICU) to a unit for COVID-19 patients only, and 107 (59%) had to manage both severe COVID-19 patients and others in the same ICU. Restriction of ICU admission occurred in one of the former 27 hospitals and 21 of the latter 107 hospitals. Shortage of N95 masks was the most serious concern regarding personal protective equipment. As for issues that raised ICU bed occupancy, difficulty undertaking or progressing rehabilitation for severe patients (42%), and the improved patients (28%), long-lasting severely ill patients (36%), and unclear isolation criteria (34%) were mentioned. Many acute medicine physicians assisted regional governmental agencies, functioning as advisors and volunteer coordinators. Conclusion: The mortality rate of COVID-19 in this study was 4.1% of all hospitalized patients and 12.5% (one in eight) severe patients. The hospitals with dedicated COVID-19 ICUs accepted more patients with severe COVID-19 and had lower ICU admission restrictions, which could be helpful as a strategy in the next pandemic.

False negative of pericardial effusion using focused assessment with sonography for trauma and enhanced CT following traumatic cardiac rupture; A case report.

BACKGROUND: The focused assessment with sonography for trauma (FAST) examination is helpful for the identification of pericardial effusion in trauma. However, in a cardiac rupture with a pericardial perforation, pericardial effusion is not always detected by FAST. We experienced the case that FAST and enhanced CT failed to detect pericardial effusion. CASE PRESENTATION: A 51-year old woman injured after falling from a height of 3 m was brought to our institute. Focused assessment with sonography for trauma and enhanced computed tomography did not reveal any pericardial effusion; however, a massive hemothorax was revealed. Because the patient's hemodynamic state had become unstable, we performed an urgent left anterolateral thoracotomy. A left pericardial perforation was detected. By performing a clamshell thoracotomy, we found a rupture of 1 cm in diameter at the left atrial appendage. The hemodynamic state was stabilized by suturing the injury site. The postoperative course was uneventful, and the patient was transferred to another hospital after 31 days of admission. CONCLUSIONS: Cardiac injury in the left atrial appendage is rare and sometimes difficult to diagnose and to repair. In the case of a blunt chest trauma with a massive hemothorax, although focused assessment with sonography for trauma gives negative results for pericardial effusion, a cardiac rupture with pericardial perforation should be considered.

Therapeutic efficacy for traumatic asphyxia with a focus on cardiac arrest.

AIM: To investigate the clinical features of traumatic asphyxia, specifically the presence of cardiac arrest and therapeutic efficacy. This review will be useful for future emergencies. METHODS: Sixteen traumatic asphyxia cases from our hospital between April 2007 and March 2019 were reviewed and divided into three groups: those experiencing cardiac arrest at the time of rescue (group A, six cases), those experiencing cardiac arrest after rescue (group B, five cases), and those who did not experience cardiac arrest (group C, five cases). RESULTS: All cases had abnormal findings in the skin or conjunctiva. The total mortality rate reached 56%. Among the 11 cases in groups A and B that resulted in cardiac arrest, 10 had an Injury Severity Score of 16 or higher and an Abbreviated Injury Scale score in the chest of 3 or higher. The patients' injuries included pneumothorax, flail chest, and pericardial hematoma. The heartbeat was restarted in seven cases, and two cases completely recovered. CONCLUSION: In some traumatic asphyxia cases, the treatment course was relatively effective even with cardiac arrest; thus, life support efforts should not be spared in such cases.

Geriatric Trauma in Patients ≧85 Years Old in an Urban District of Japan.

Japan's population has been skewing toward the elderly, but the outcomes of advanced elderly trauma are not clear. Here we compared the outcomes of very elderly trauma patients (≧85 years old) with those of 65- to 84-year-old trauma patients. We retrospectively reviewed the medical records of patients treated at Hyogo Emergency Medical Center from August 2010 to August 2016; 631 patients were entered in the study. We divided them into the younger geriatrics (YG group, 65-84 years old: n=534) and older geriatrics (OG group, ≧85 years old: n=97). The group's patient characteristics, mortality, 1-year survival rate, and Barthel index were tabulated and compared. The patients' mean age was 75.6±7.5 years. There was no significant difference in mortality between the YG and OG groups (9.6% vs. 15.1%, odds ratio [OR] 1.73; 95% confidence interval [CI] 0.93-3.23, p=0.083). The 1-year survival rate (94.4% vs. 77.8%, OR 0.19, 95% CI 0.07-0.51; p<0.01) and Barthel index (Median score; 100 (IQR: 85-100) vs. 80 (IQR: 15-95), OR 0.98, 95% CI 0.97 to 0.99, p<0.01) differed significantly between the groups. Our study did not find a significant difference in-hospital mortality between patients in the YG group and those in the OG group.

Preoperative fluid restriction for trauma patients with hemorrhagic shock decreases ventilator days.

Aim: In recent years, with the concept of damage control resuscitation, hemostasis and preoperative fluid restriction have been carried out, but there is controversy regarding the effectiveness of fluid restriction. Methods: From April 2007 to March 2013, 101 trauma patients presented with hemorrhagic shock (systolic blood pressure ≤90 mmHg) at the prehospital or emergency department and were admitted to Hyogo Emergency Medical Center (Hyogo, Japan). They underwent emergency hemostasis by surgery and transcatheter arterial embolization. We compared two groups in a historical cohort study, the aggressive fluid resuscitation (AR) group, which included 59 cases treated in the period April 2007-March 2010, and the fluid restriction (FR) group, which included 42 cases treated in the period April 2010-March 2013. Results: There was no difference between both groups in patient background (heart rate, 110 b.p.m.; systolic blood pressure, 70 mmHg). The Injury Severity Score was 34 (AR) versus 38 (FR) (not significant). Preoperative infusion volume of crystalloid significantly decreased, from 2310 mL (AR) to 1025 mL (FR) (P ≤ 0.01). There was no difference in mortality (36% [AR] versus 41% [FR]). Ventilator days significantly decreased, from 8.5 days (AR) to 5.5 days (FR) (P = 0.02). Conclusions: Preoperative fluid restriction for trauma patients with hemorrhagic shock did not improve mortality, but it decreased ventilator days by reducing the perioperative plus water balance and it might contribute to perioperative intensive care.

Vasodilating prostaglandin E1 does not reproduce interleukin-1ß-induced oxygen metabolism abnormalities in rabbits.

Background: We have reported that administration of recombinant human interleukin (IL)-1ß induced circulatory shock in rabbits by causing overproduction of vasodilating prostaglandin(s) and simultaneously impaired oxygen metabolism by causing an abnormal dependence of oxygen consumption (VO2) on oxygen delivery (DO2). The present study was carried out to compare the effect of administration of exogenous PGE1 with that of IL-1ß on oxygen metabolism. Methods: Sixteen rabbits were assigned to one of three groups and given a single injection of 10 µg/kg IL-1ß (IL-1ß group, n = 5), continuous infusion of 1 µg/kg/min PGE1 (PGE1 group, n = 6), or saline (control group, n = 5). All rabbits were subjected to stepwise cardiac tamponade to decrease DO2 by inflating a balloon placed into the pericardial sac. The VO2/DO2 relation was analyzed by the dual-line method. Results: Both IL-1ß and PGE1 decreased the baseline value of mean arterial pressure by approximately 25% without inducing significant alteration of the cardiac index. With respect to the VO2/DO2 relation, the slope of the supply-independent line was significantly increased in the IL-1ß group (y = 0.13x + 6.4), but not in the PGE1 group (y = 0.01x + 10.0) compared to that in the control group (y = 0.05x + 8.7). Conclusion: These results indicate that simple vasodilation and hypotension induced by administration of PGE1 are insufficient to account for the abnormal oxygen metabolism induced by IL-1ß.