Refractory Circulatory Failure Research Articles

47: VA-ECMO as a Bridge to Recovery in Refractory Circulatory Failure due to Bupropion Overdose

47: VA-ECMO as a Bridge to Recovery in Refractory Circulatory Failure due to Bupropion Overdose

Refractory circulatory failure in COVID-19 patients treated with veno-arterial ECMO a retrospective single-center experience.

In this retrospective case series, survival rates in different indications for veno-arterial extracorporeal membrane oxygenation (VA-ECMO) and differential diagnoses of COVID-19 associated refractory circulatory failure are investigated. Retrospective analysis of 28 consecutive COVID-19 patients requiring VA-ECMO. All VA-ECMO's were cannulated peripherally, using a femoro-femoral cannulation. At VA-ECMO initiation, median age was 57 years (IQR: 51-62), SOFA score 16 (IQR: 13-17) and norepinephrine dosing 0.53μg/kg/min (IQR: 0.35-0.87). Virus-variants were: 61% wild-type, 14% Alpha, 18% Delta and 7% Omicron. Indications for VA-ECMO support were pulmonary embolism (PE) (n = 5, survival 80%), right heart failure due to secondary pulmonary hypertension (n = 5, survival 20%), cardiac arrest (n = 4, survival 25%), acute heart failure (AHF) (n = 10, survival 40%) and refractory vasoplegia (n = 4, survival 0%). Among the patients with AHF, 4 patients suffered from COVID-19 associated heart failure (CovHF) (survival 100%) and 6 patients from sepsis associated heart failure (SHF) (survival 0%). Main Complications were acute kidney injury (AKI) 93%, renal replacement therapy was needed in 79%, intracranial hemorrhage occurred in 18%. Overall survival to hospital discharge was 39%. Survival on VA-ECMO in COVID-19 depends on VA-ECMO indication, which should be considered in further studies and clinical decision making. A subgroup of patients suffers from acute heart failure due to inflammation, which has to be differentiated into septic or COVID-19 associated. Novel biomarkers are required to ensure reliable differentiation between these entities; a candidate might be soluble interleukin 2 receptor.

Extracorporeal cardiopulmonary resuscitation-When the heart no longer functions

Extracorporeal cardiopulmonary resuscitation (ECPR) is an option for restoring blood circulation in patients with refractory circulatory failure. While conventional resuscitation measures are being continued, venoarterial extracorporeal membrane oxygenation (VA ECMO) is established in patients with cardiac arrest. This bypass can compensate for the functions of the heart and lungs until recovery of organ function. The benefit of ECPR compared to conventional resuscitation appears to be evident, especially after aprolonged resuscitation period; however, in three prospective randomized controlled studies an advantage has not yet been conclusively proven for widespread use in clinical routine. ECPR systems are complex and resource-intensive and should therefore be limited to specialized centers where sufficient numbers of patients are treated to ensure ahigh level of expertise in the teams.

Cryptococcal Pneumonia: An Unusual Complication in a COVID-19 Patient.

Cryptococcal superinfection is a rare but potentially fatal complication, especially if its detection and subsequent treatment are delayed. Histopathological findings of pulmonary parenchyma from a deceased patient with these complications were acquired. Quite interestingly, only a minimal inflammatory reaction could be seen in an individual with no previously known immune suppression, indicating a disturbance of the immune system. This finding was well in concordance with the described changes in cellular immunity in COVID-19. We report the case of a 60 year old male with critical coronavirus disease 2019 (COVID-19) complicated by cryptococcal pneumonia and multiorgan failure. Both X-ray and CT scans revealed lung infiltrates corresponding with COVID-19 infection early after the onset of symptoms. Despite receiving standard treatment, the patient progressed into multiple organ failure, requiring mechanical ventilation, circulatory support, and haemodialysis. Cryptococcus neoformans was detected by subsequent BAL, and specific antifungal treatment was instituted. His clinical status deteriorated despite all treatment, and he died of refractory circulatory failure after 21 days from hospital admission. Histopathological findings confirmed severe diffuse alveolar damage (DAD) caused by COVID-19 and cryptococcal pneumonia. Timely diagnosis of cryptococcal superinfection may be challenging; therefore, PCR panels detecting even uncommon pathogens should be implemented while taking care of critical COVID-19 patients.

Lethal diquat poisoning manifests as acute central nervous system injury and circulatory failure: A retrospective cohort study of 50 cases

SummaryBackgroundThe mortality rate of patients with diquat (DQ) poisoning is extremely high due to insufficient understanding of DQ-induced injury. This study aimed to summarize the characteristics of DQ poisoning as well as analyse the correlation between plasma DQ concentration and patient outcomes, thus providing a new strategy for diagnosis and treatment.MethodsThis single-centre retrospective cohort study was conducted at the Emergency Department of the First Affiliated Hospital, Zhejiang University School of Medicine, China, between Oct 9, 2019 and March 10, 2022. 50 patients, whose plasma or urine samples tested positive for diquat and negative for paraquat by high performance liquid chromatography-tandem mass spectrometry, were included in the study.FindingsThe mortality rate of acute DQ poisoning was 25 (50%) of 50. Compared with the survival group, the death group presented significantly higher initial plasma DQ concentration (Cp1), aspartate aminotransferase, alanine aminotransferase, serum creatinine, and creatine kinase-MB (P < 0.05). We found that six (24.0%) patients died of central nervous system injury, six (24.0%) patients died of refractory circulatory failure, and 13 (52.0%) patients died of central nervous system injury combined with circulatory failure. Receiver operator characteristic curve analysis showed that the area under the curve of Cp1 was 0.967 (95% CI: 0.911, 1.000), and the cut-off value was 3516.885 ng/mL (sensitivity, 90.9%; specificity, 96.0%).InterpretationLethal DQ poisoning is primarily associated with serious brain and vascular injury, as well as a high rate of mortality. Further research into the mechanisms of refractory circulatory failure and central nerve system damage could help reduce mortality.FundingThere are no funding sources to declare.

Clinical features of 86 cases of acute diquat poisoning

To explore the clinical features of acute diquat (DQ) poisoning, and further improve the awareness of acute DQ poisoning. A retrospective analysis was performed on the clinical data of patients with acute DQ poisoning diagnosed in the emergency department of the Second Hospital of Hebei Medical University from January 1, 2019 to December 31, 2021. The clinical data included age, gender, exposure routes, presence of pesticides (drugs) mixture poisoning, dosage of poison, the time from taking poisoning to admitting in the emergency department, clinical manifestations, laboratory data, treatment, hospital days, prognosis and survival days. The number of cases who firstly complained of acute DQ poisoning in the past three years were 19 cases in 2019, 28 cases in 2020, and 51 cases in 2021. A total of 12 patients were excluded due to being diagnosed paraquat (PQ) poisoning by toxicology detection. Finally, 86 cases of acute DQ poisoning were included, including 80 cases of oral DQ poisoning, 1 case of intramuscular injection, 1 case of binocular contact and 4 cases of dermal exposure. In 80 cases of oral DQ poisoning, there were 70 cases of diquat poisoning alone (42 cases survived, 28 cases died) and 10 cases of pesticide mixture poisoning (6 cases survived, 4 cases died). The time from oral poisoning to admitting in the emergency department was 0.5-96.0 hours, with an average of (8.6±5.8) hours. The time of intramuscular injection poisoning to admitting in the emergency department was 3 hours. The time of dermal exposure to admitting in the emergency department was relatively long, with an average of 66.1 hours. The time from oral simple DQ poisoning to death was 12.0-108.0 hours, and the time from oral mixed DQ poisoning to death was 24.0-576.0 hours. A total of 70 patients with oral diquat poisoning alone presented various degrees of multiple organ injuries. All patients presented gastrointestinal symptoms such as nausea and vomiting. Renal injury and central nervous system injury were the most significant and closely related to the prognosis. Acute oral DQ poisoning can cause to multiple organ injuries, and the clinical manifestations are related to the dose of the poison. In severe cases, acute renal failure and refractory circulatory failure occur within 24 hours after poisoning, and severe central nervous system injury with disturbance of consciousness as the primary manifestation occurs within 36 hours, followed by multiple organ failure until death.

Pediatric patients requiring extracorporeal membrane oxygenation in heart failure: 30-day outcomes; mid- and long-term survival. A single center experience.

Nowadays, an increasing number of neonatal and pediatric patients with severe heart failure benefits from extracorporeal membrane oxygenation (ECMO) support. A total of 39 pediatric patients needed venoarterial ECMO (vaECMO) support in our department between January 2008 and December 2016. Patients were retrospectively divided in two groups: 30-day survivor group (17 patients) and 30-day nonsurvivor group (22 patients). Outcome and factors predictive for 30-day mortality and mid- as well as long-term survival up to 7-year follow-up were analyzed by univariate analysis and Kaplan-Meier survival estimation. Basic demographics and preoperative characteristics did not differ between groups (P > 0.05). 67% of patients were successfully weaned off ECMO and 44% survived 30-day after ECMO application. After 7-year follow-up 28% of pediatric patients were alive. Thirty-day survivors were significantly more likely to undergo elective cardiac surgery (P = 0.001), whereas significantly more 30-day nonsurvivors underwent urgent surgery (P = 0.004). Odds of incidence of catecholamine refractory circulatory failure, failed myocardial recovery, and cerebral edema was significantly higher in 30-day nonsurvivor group (41.6-fold, 16-fold, and 2.5-fold, respectively). Kaplan-Meier survival estimation analysis revealed significant differences in terms of mid- and long-term survival among neonates, infants, toddlers, and preadolescents (Breslow P = 0.037 and Log-Rank P = 0.028, respectively). vaECMO provides an efficient therapy option for life-threatening heart disorders in neonates and pediatric patients being at high risk for myocardial failure leading to circulatory arrest. Urgency of surgery effected on higher mortality, but there was no difference in terms of mortality in 30-day survivor group in comparison to 30-day nonsurvivor group among neonates, infants, toddlers, and preadolescents.

Timing and modes of death after pediatric out-of-hospital cardiac arrest resuscitation

AimTo determine the timing and modes of death of children admitted to a pediatric critical care unit (PICU) of a tertiary care center after an out-of-hospital cardiac arrest (OHCA). MethodsThis is a retrospective descriptive study at a tertiary care PICU of all consecutive patients <18 years old who received ≥1 min of chest compressions, had return of spontaneous circulation (ROSC) for ≥20 min, and were admitted to the PICU after an OHCA. Modes of death were classified as brain death (BD), withdrawal due to neurologic prognosis (W/D-neuro), withdrawal for refractory circulatory failure (W/D-RCF), and re-arrest without ROSC (RA). Results191 consecutive patients were admitted to the PICU from February 2005 to May 2013 after an OHCA. Eighty-six(45%) patients died prior to discharge: BD in 47%(40/86), W/D-neuro in 34%(29/86), W/D-RCF in 10%(9/86), and RA in 9%(8/86). Time to death was longer for patients with W/D-neuro: 4 days [1, 5] and BD 4 days [1, 5](p < 0.01) as opposed to those with W/D-RCF (1 day[1, 2]) and RA(1 day[0.5, 1]). Of patients who underwent W/D-neuro, 9/29(31%) died within 3 days of PICU admission and 20/29(69%) ≥3 days. Of patients who died after W/D-neuro, 12/29(41%) received therapeutic hypothermia, 27/29(93%) underwent EEG monitoring, 21/29(72%) had a brain CT, and 13/29(45%) had a brain MRI. All MRIs showed signs of hypoxic-ischemic injury. ConclusionNeurologic injury was the most common mode of death post-resuscitation care OHCA after in a tertiary care center PICU. Neurologic prognostication impacts the outcome of a large proportion of patients after OHCA, and further studies are warranted to improve its reliability.

Four-year experience of providing mobile extracorporeal life support to out-of-center patients within a suprainstitutional network—Outcome of 160 consecutively treated patients

AimMobile extracorporeal life support (ECLS) may soon be on the verge to become a fundamental part of emergency medicine. Here, we report on our four-year experience of providing advanced mechanical circulatory support for out-of-center patients within the Düsseldorf ECLS Network (DELSN). MethodsThis retrospective cohort study analyses the outcome of 160 patients with refractory circulatory failure consecutively treated with mobile veno-arterial extracorporeal membrane oxygenation (vaECMO) between July 2011 and October 2015 within the DELSN. ResultsOut of the 160 patients (56±16years, vaECMO initiation under CPR 68%), 59 patients (36%) survived to primary discharge, with 50 patients (31%) still alive after a median follow-up of 1.74 years. Time-discrete mortality was highest during the first 24h. There was no difference between survivors and non-survivors regarding age, etiology of circulatory failure, presence of CPR during implantation or distance to implantation site. Incidence of kidney injury requiring dialysis (61% vs. 24%, p<0.0001), shock liver (27% vs. 12%, p=0.031) and visceral ischemia (19% vs. 3%, p=0.013) were the only complications increased in non-survivors. Subgroup analysis showed no significant outcome difference for ECPR vs. non-ECPR patients. Outcome was significantly impaired with initial neuron-specific enolase ≥45.4μg/L (AUC 0.75, p<0.0001) and lactate ≥5.5mmol/L (AUC 0.70, p<0.0001). Program-year-dependent in-center mortality showed an increasing trend, while program-year-dependent follow-up mortality decreased over time. ConclusionsThis study illustrates that regional mobile ECLS rescue therapy can be provided with encouraging outcomes, although patient selection criteria and early outcome parameters reflecting on therapy success or futility still need to be refined.

Place de l’assistance respiratoire et circulatoire extracorporelle de courte durée (ECMO), post-cardiotomie exclue, dans la prise en charge des défaillances graves du nouveau-né et de l’enfant

Extracorporeal membrane oxygenation is used as a last resort during neonatal and pediatric resuscitation in case of refractory circulatory or respiratory failure under maximum conventional therapies. Different types of ECMO can be used depending on the initial failure. The main indications for ECMO are refractory respiratory failure (acute respiratory distress syndrome, status asthmaticus, severe pneumonia, meconium aspiration syndrome, pulmonary hypertension) and refractory circulatory failure (cardiogenic shock, septic shock, refractory cardiac arrest). The main contraindications are a gestational age under 34weeks or birth weight under 2kg, severe underlying pulmonary disease, severe immune deficiency, a neurodegenerative disease and hereditary disease of hemostasis. Neurological impairment can occur during ECMO (cranial hemorrhage, seizure or stroke). Nosocomial infections and acute kidney injury are also frequent complications of ECMO. The overall survival rate of ECMO is about 60%. This survival rate can change depending on the initial disease: from 80% for meconium aspiration syndrome to less than 10% for out-of-hospital refractory cardiac arrest. Recently, mobile ECMO units have been created. These units are able to perform ECMO out of a referral center for untransportable critically ill patients.

A Suprainstitutional Network for Remote Extracorporeal Life Support: A Retrospective Cohort Study

ObjectivesThis study sought to evaluate patient outcome within the Düsseldorf Extracorporeal Life Support (ECLS) Network, a suprainstitutional network for rapid-response remote ECLS and to define survival-based predictors. BackgroundMobile venoarterial extracorporeal membrane oxygenation (vaECMO) used for ECLS has become a treatment option for a patient population with an otherwise fatal prognosis. However, outcome data remain scarce and institutional standards required to manage these patients are still poorly defined. MethodsThis retrospective cohort study analyzes the outcome of 115 patients consecutively treated between July 2011 and October 2014 within the Düsseldorf ECLS Network due to refractory circulatory failure. ResultsOf the 115 patients (56 ± 15 years of age, vaECMO initiation under cardiopulmonary resuscitation [CPR] 77%, CPR duration 45 [range 5 to 90] min), 50 patients (44%) survived to primary discharge and 38 patients (33%) were alive after a median follow-up of 1.5 years (95% confidence interval [CI]: 1.2 to 1.7). Thirty-seven (97%) of the long-term survivors showed a favorable neurological outcome. Risk factors associated with mortality during vaECMO were CPR duration (hazard ratio [HR]: 1.006; 95% CI: 1.00 to 1.01) and ischemic stroke (HR: 2.63; 95% CI: 1.52 to 4.56). Risk factors associated with mortality after vaECMO weaning were renal failure (HR: 6.60; 95% CI: 2.72 to 16.01) and sepsis (HR: 3.6; 95% CI: 1.50 to 8.69). Visceral ischemia had a negative impact (HR: 0.30; 95% CI: 0.11 to 0.84) whereas assist device implantation promoted successful vaECMO weaning (HR: 2.95; 95% CI: 1.65 to 5.25). Further, 3 distinct risk groups with significant differences in survival could be identified, demonstrating that in patients with no or short CPR mortality was not conditioned by age, whereas in patients with prolonged CPR young age was associated with increased survival. ConclusionsThis study illustrates the implementation of a suprainstitutional ECLS Network. Further, our data suggest that mobile vaECMO is beneficial for a larger patient population than actually expected, especially regarding young patients presenting with prolonged CPR or patients regardless of age with no or short CPR.

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Introduction: Veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) is a rescue modality in refractory circulatory failure or severe respiratory failure, with a mortality rate of approximately 50%. However, little evidence exists regarding in-hospital mortality after discontinuing VA-ECMO. Hypothesis: The present study was conducted to investigate for in-hospital mortality of patients after discontinuing VA-ECMO. Methods: Between October 2008 and June 2012, patients undergoing VA-ECMO due to refractory postcardiotomy shock, cardiogenic shock and/or pulmonary dysfunction were screened, and those successfully weaned from VA-ECMO were included. Patients <18yo, or subsequently placed on a left ventricular assist device and/or undergoing transplantation were excluded. Results: Of 84 patients who underwent VA-ECMO, 50 patients were successfully weaned. There were 21(42%) surgical and 29 (58%) medical patients. The average age (± SD) was 65 ± 11yr, 80% were male, median hospital stay was 32.5d (range 19-61), and mean APACHE II score was 28.6 ± 7.2. After discontinuing VA-ECMO, 34 patients survived and 16 died. The median duration from discontinuing VA-ECMO to death was 9.5d (range 4.5-14.8). Causes of mortality included sepsis in 5 (31%), hepatic failure in 3 (19%), low cardiac output syndrome in 2 (13%), respiratory failure in 1 (6%), and other in 5 (31%). Two patients died within 48 hours of discontinuation. In multiple logistic regression analyses, continuous renal replacement therapy (CRRT) during VA-ECMO (OR: 45.9, 95%, CI 3.0 – 699.7) was significantly associated with increased in-hospital mortality. Conclusions: In-hospital mortality after discontinuing VA-ECMO is 32%, which is similar to previous study (J Thorac Cardiovasc Surg. 2001; 122: 92-102). This study shows that CRRT is a significant predictor of in-hospital mortality after discontinuing VA-ECMO and the main cause of death is sepsis.

Outcomes, long-term quality of life, and psychologic assessment of fulminant myocarditis patients rescued by mechanical circulatory support*

Myocarditis is a rare disease that may progress rapidly to refractory cardiogenic shock and death. In such situations, emergent initiation of mechanical circulatory assistance is the only therapeutic option to rescue these dying patients. This study was designed to evaluate the outcomes, health-related quality of life and frequencies of anxiety, depression and posttraumatic stress disorder symptoms in fulminant myocarditis patients rescued by mechanical circulatory assistance, since these major components of outcome evaluation after serious illnesses have not yet been assessed in this setting. A retrospective, single-center, observational study and a cross-sectional survey to assess health-related quality of life by the Short Form-36 questionnaire and frequencies of anxiety, depression and posttraumatic stress disorder symptoms by the Hospital Anxiety and Depression Scale and the Impact of Event Scale, respectively. An 18-bed tertiary intensive care unit in a university hospital. We analyzed the short- and long-term outcomes of 41 patients hospitalized at our institution between 2003 and 2009 and who received either a Thoratec BiVAD (Thoratec, Pleasanton, CA) (n = 6) or extracorporeal membrane oxygenation (n = 35) to combat refractory cardiogenic shock due to fulminant myocarditis. Intensive care unit survival was 68%, and four (10%) patients underwent heart transplantation. Independent predictors of in-intensive care unit death were Simplified Acute Physiology Score II ≥56 (odds ratio = 10.23) and troponin Ic ≥12 μg/L (odds ratio = 7.49) at admission. Complete follow-up (median, 525 days) was available for 26 of 28 survivors. Compared to age- and sex-matched controls, Short Form-36 evaluation of health-related quality of life revealed satisfactory mental health and vitality but persistent physical and psychosocial-related difficulties. Lastly, anxiety, depression, and/or posttraumatic stress disorder symptoms were reported by 38%, 27% and 27% of the patients, respectively. Mechanical circulatory assistance rescued 68% of patients with refractory circulatory failure due to fulminant myocarditis. Greater disease severity and higher troponin Ic levels at extracorporeal membrane oxygenation initiation predicted poorer prognosis. Because up to one-third of the patients reported anxiety, depression, and/or posttraumatic stress disorder symptoms, strategies aimed at attenuating their emotional and psychologic distress might significantly improve their long-lasting well-being.

Zwei Autopsiefälle mit systemischer Amyloidose – Fall 11/2010

A 37-year old patient was admitted with upper abdominal pain, vomiting and diarrhea. A 38-year-old patient was admitted for liver failure. Case 1 was diagnosed with an AL amyloidosis due to deposition of the immunoglobulin light chain kappa in all tissues analyzed. In the bone marrow plasma cells were increased to 20-30%. Case 2 suffered from AA amlyoidosis secondary to familial mediterranean fever and underwent dialysis treatment for years. He was positive for hepatitis B and C. Patient 1 developed refractory nephrotic syndrome and low blood pressure. During hemodialysis circulatory failure occured and she died during resuscitation. In patient 2 a flare of chronic hepatitis B was found and treated with antiviral therapy. He was referred to ICU for rectal bleeding and developed pulmonary arrest. After resuscitation he died because of lactate acidosis and refractory circulatory failure. Both cases were subjected to autopsy. The vast majority (90%) of amyloidoses are due to acquired AA or AL amyloidosis. Prognosis remains poor, in particular when cardiac and vascular involvement occurs.

Central Extracorporeal Membrane Oxygenation for Septic Shock in an Adult With H1N1 Influenza

Extracorporeal membrane oxygenation has been used as rescue therapy for respiratory failure caused by pandemic hemagglutanin-1 and neuroaminadase-1 (H1N1) influenza, but it is unclear as to whether it can be also used for refractory circulatory failure. A previously healthy 29-year-old woman presented with pneumonitis and septic shock. She deteriorated, despite multiple pharmacologic and ventilatory strategies, so she was placed on central (atrio-aortic) extracorporeal membrane oxygenation for 4 days. After a protracted intensive care stay, she recovered and is undergoing rehabilitation. In particularly severe cases of H1N1 influenza, central extracorporeal membrane oxygenation can completely supplant both cardiac and pulmonary function until the patient recovers from the infection.

Oral arsenic trioxide poisoning and secondary hazard from gastric content

In a suicide attempt, a 54-year-old man ingested arsenic trioxide. Gastric lavage was performed, but most of the poison remained as a mass in his stomach. A total gastrectomy was also performed to avoid intestinal perforation and arsenic poisoning. After the operation, he developed ventricular fibrillation. At one point, his circulation recovered spontaneously, but he later died from refractory circulatory failure. Many medical staff members were exposed to fumes from the patient's stomach. Some of the staff were diagnosed with corneal erosion or laryngitis. Because arsenic trioxide reacts with acid to produce arsine, the symptoms experienced by medical staff are directly attributable to arsine produced as a result of the reaction of arsenic trioxide with gastric acid. This case highlights the need for the introduction of protective measures to safeguard medical staff from exposure to arsine gas during the treatment of patients poisoned from ingested arsenic trioxide.

Le ventricule droit dans l’embolie pulmonaire

Acute circulatory failure that complicates massive pulmonary embolism (MPE) is the major form of acute cor pulmonale (ACP). This kind of right ventricular dysfunction results from the inability of the right ventricle to handle an acute excess of pressure, and is directly related to the degree of pulmonary vascular obstruction. Echocardiography is the best and more accurate means of detecting ACP. Even if finding ACP on the echocardiographic study indicates the presence of a large obstruction, it does not necessarily imply a negative prognosis and does not require thrombolytic therapy. Only associated metabolic acidosis indicates a high risk of death from refractory circulatory failure.

Persistent Preload Defect in Severe Sepsis Despite Fluid Loading: A Longitudinal Echocardiographic Study in Patients With Septic Shock

To investigate the rate of recovery from septic shock in patients with suspected left ventricular (LV) preload deficiency and LV systolic dysfunction. A monitoring period was defined by the need for inotropic/vasopressor support, and LV function was assessed daily during this period by bedside two-dimensional echocardiography (2D-ECHO). University hospital ICU. During a 5-year period, 90 patients with an episode of septic shock (60% with gram-positive bacteria as the causative agent) were consecutively enrolled in the study (mean age, 55 +/- 18 years). Standard volume resuscitation combined with inotropic/vasopressor support was used to maintain systolic arterial pressure > 90 mm Hg. All patients received mechanical ventilation because of associated respiratory failure. The average duration of hemodynamic support was 4.4 +/- 1.6 days. Thirty-four patients were weaned from hemodynamic support during the monitoring period and ultimately recovered (group I). Twenty-eight patients died from refractory circulatory failure during the monitoring period, and 28 died later from ARDS or multiple organ dysfunction syndrome, leading to a 62% overall mortality rate (group II). Daily bedside LV volumes and ejection fraction (LVEF) were recorded using 2D-ECHO. Data obtained at the start (day 1 and day 2) and end of the monitoring period (day n) were compared. LV end-diastolic volume was within the normal range of our laboratory values in all patients, but was initially smaller in group II than in group I, and remained so despite fluid loading. LVEF was significantly depressed in all patients, resulting in severe reduction in LV stroke volume (LVSV), which was initially more marked in group I. In group I patients, LVEF significantly improved during the monitoring period, resulting in an increase in LVSV. 2D-ECHO changes during hemodynamic support in 90 septic patients confirmed defective LV preload with a propensity to worsen despite fluid loading in nonsurvivors (62% in the present study). Our results are also in agreement with previous studies reporting depressed LV systolic function at the initial phase of septic shock. Since LV dysfunction was more marked in patients who recovered, we suggest that the exact significance of this finding should be reevaluated.

The pathophysiology of irreversible hemorrhagic shock in monkeys

Irreversible shock was produced in pig-tail monkeys by hemorrhaging them to a mean arterial pressure of 40 mm Hg and maintaining that pressure until (15%) “uptake” of blood signaled decompensation. Reinfusion of the remainder of the blood, plus additional lactated Ringer's solution restored hemodynamic function and urine flow temporarily, but in spite of continuing and increasing crystalloid infusions, refractory circulatory failure ensued, characterized by decreasing mean arterial pressure, widening pulse pressure, decreased systemic vascular resistance, progressive hemodilution, diminished systemic oxygen transport, and narrowed arteriovenous oxygen differences. Cardiac outputs were normal or supranormal, central venous, right atrial, and pulmonary artery pressures were well sustained and left atrial and left ventricular end diastolic pressures were normal or low indicating that neither inadequate venous return nor cardiac failure were to blame. Significant anatomic systemic arteriovenous shunting did not occur but either abnormal oxygen transport or inability of cells to utilize oxygen seemed likely. Regional blood flows, with the exception of renal, splenic, and bronchial flows were restored to normal in the postresuscitative period and myocardial adrenal, hepatic, and intestinal flows became supranormal. The pattern observed is unlike that after endotoxin administration and may provide a clue to the identity of the factor(s) responsible for this vasomotor collapse.