Bolus injection of thrombolytic agents during cardiopulmonary resuscitation for massive pulmonary embolism

Cardiac arrest in special circumstances

PURPOSE OF REVIEW

European Resuscitation Council Guidelines for Cardiopulmonary Resuscitation prioritize treatments like chest compression and defibrillation, known to be highly effective for cardiac arrest from cardiac origin. This review highlights the need to modify this approach in special circumstances.

RECENT FINDINGS

Potentially reversible causes of cardiac arrest are clustered into four Hs and four Ts (Hypoxia, Hypovolaemia, Hyperkalaemia/other electrolyte disorders, Hypothermia, Thrombosis, Tamponade, Tension pneumothorax, Toxic agents). Point-of-care ultrasound has its role in identification of the cause and targeting treatment. Time-critical interventions may even prevent cardiac arrest if applied early. The extracorporeal CPR (eCPR) or mechanical CPR should be considered for bridging the period needed to reverse the precipitating cause(s). There is low quality of evidence available to guide the treatment in the majority of situations. Some topics (pulmonary embolism, eCPR, drowning, pregnancy and opioid toxicity) were included in recent ILCOR reviews and evidence updates but majority of recommendations is based on individual systematic reviews, scoping reviews, evidence updates and expert consensus.

SUMMARY

Cardiac arrests from reversible causes happen with lower incidence. Return of spontaneous circulation and neurologically intact survival can hardly be achieved without a modified approach focusing on immediate treatment of the underlying cause(s) of cardiac arrest.

Safety, Efficacy of an Accelerated Regimen of Low-Dose Recombinant Tissue-Type Plasminogen Activator for Reperfusion Therapy of Acute Pulmonary Embolism

Controversy persists regarding the safety and efficacy of an accelerated low-dose recombinant tissue-type plasminogen activator (rt-PA) regimen for reperfusion therapy in acute pulmonary embolism. This study describes the outcomes of an accelerated low-dose rt-PA regimen for the treatment of acute pulmonary embolism in Vietnamese patients. This was a case series from October 2014 to October 2020 from 9 hospitals across Vietnam. Patients presenting with acute pulmonary embolism with high to intermediate mortality risk were administered alteplase 0.6 mg per kilogram (maximum of 50 mg) over 15 min. The main outcomes were the proportion who survived to hospital discharge and at 3 months as well as in-hospital hemorrhage (major and minor according to International Society of Thrombosis and Hemhorrage definitions). A total of 80 patients were enrolled: 48 (60%) with high risk for mortality and 32 patients (40%) with intermediate risk for mortality. A total of 7 (8.8%) died in hospital. All deaths occurred in the high-risk mortality group. The 73 patients who were discharged alive remained alive at 3 months follow up. During hospitalization, 1 patient (1.3%) suffered major bleeding, and 7 (8.8%) had minor bleeding. An accelerated thrombolytic regimen with alteplase 0.6 mg/kg (maximum of 50 mg) over 15 min for acute pulmonary embolism appeared be effective and safe in a case series of Vietnamese patients.

Drug use during adult advanced cardiac life support: An overview of reviews

AIM

To conduct an overview of systematic reviews and meta-analyses to summarize the ever-growing evidence on drug use during advanced life support.

METHODS

We searched Embase, Medline, Cochrane central register of controlled trials and Web of science for systematic reviews and meta-analyses reporting on drug use during advanced life support from inception to March, 2020. Two reviewers independently assessed all abstracts for eligibility, extracted data and assessed risk of bias using the AMSTAR-2 tool. Corrected covered areas were calculated from publication citation matrices to account for potential risk of bias. Data were graphically represented using forest plots.

RESULTS

Twenty-two head-to-head drug comparisons from 47 included articles were analysed. Adrenaline significantly increases the incidence of return of spontaneous circulation and survival to hospital discharge, but not the incidence of neurological intact survival. Vasopressin alone or in combination with adrenaline is not superior to adrenaline alone. There is a trend favouring lidocaine over amiodarone in shockable cardiac arrest. The risk of bias assessment of included studies ranged from very low to very high and the overlap between articles was moderate to high.

CONCLUSIONS

In line with the guidelines, we currently suggest that a standard dose of adrenaline should be administered during resuscitation, however, studies assessing lower doses of adrenaline are pressing. There is no rationale for the combination of vasopressin and adrenaline or vasopressin alone instead of adrenaline. In addition, lidocaine is a valuable alternative for amiodarone and maybe even preferable for shockable cardiac arrest. However more research is necessary.

Massive Pulmonary Embolism Causing Cardiac Arrest Managed with Systemic Thrombolytic Therapy: A Case Report

BACKGROUND Approximately 290 000 cases of in-hospital cardiac arrest occur annually, the majority of which are due to cardiac or respiratory causes. Cardiac arrest due to acute pulmonary embolism (PE) is associated with a 90% incidence of mortality and, if identified, it can be treated with systemic thrombolytics. Here, we describe a case in which the outcome for such an event was favorable. CASE REPORT A 66-year-old woman was admitted with multiple rib and left ankle fractures due to accidental trauma. Before undergoing orthopedic surgery, she experienced a cardiac arrest with pulseless electrical activity, which was witnessed. She had refractory hypoxia and hypotension following intubation and a brief initial return of spontaneous circulation (ROSC) before a second cardiac arrest. A 100-mg bolus dose of systemic thrombolytic therapy was promptly administered, with rapid achievement of sustained ROSC. The results of a subsequent electrocardiogram, echocardiogram, and computed tomography scan further supported the diagnosis of acute PE with right heart strain. Supportive care in the Intensive Care Unit resulted in full neurological recovery and she was discharged to a physical rehabilitation facility 12 days after her cardiac arrest. CONCLUSIONS Systemic thrombolytic therapy is beneficial for cardiac arrest due to acute PE.

[Cardiac arrest under special circumstances]

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

[Adult advanced life support]

These European Resuscitation Council Advanced Life Support guidelines are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the prevention of and ALS treatments for both in-hospital cardiac arrest and out-of-hospital cardiac arrest.

Thrombolytic therapy for pulmonary embolism

BACKGROUND

Thrombolytic therapy is usually reserved for people with clinically serious or massive pulmonary embolism (PE). Evidence suggests that thrombolytic agents may dissolve blood clots more rapidly than heparin and may reduce the death rate associated with PE. However, there are still concerns about the possible risk of adverse effects of thrombolytic therapy, such as major or minor haemorrhage. This is the fourth update of the Cochrane review first published in 2006.

OBJECTIVES

To assess the effects of thrombolytic therapy for acute pulmonary embolism.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL databases and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 17 August 2020. We undertook reference checking to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared thrombolytic therapy followed by heparin versus heparin alone, heparin plus placebo, or surgical intervention for people with acute PE (massive/submassive). We did not include trials comparing two different thrombolytic agents or different doses of the same thrombolytic drug.

DATA COLLECTION AND ANALYSIS

Two review authors (ZZ, QH) assessed the eligibility and risk of bias of trials and extracted data. We calculated effect estimates using the odds ratio (OR) with a 95% confidence interval (CI) or the mean difference (MD) with a 95% CI. The primary outcomes of interest were death, recurrence of PE and haemorrhagic events. We assessed the certainty of the evidence using GRADE criteria.

MAIN RESULTS

We identified three new studies for inclusion in this update. We included 21 trials in the review, with a total of 2401 participants. No studies compared thrombolytics versus surgical intervention. We were not able to include one study in the meta-analysis because it provided no extractable data. Most studies carried a high or unclear risk of bias related to randomisation and blinding. Meta-analysis showed that, compared to control (heparin alone or heparin plus placebo), thrombolytics plus heparin probably reduce both the odds of death (OR 0.58, 95% CI 0.38 to 0.88; 19 studies, 2319 participants; low-certainty evidence), and recurrence of PE (OR 0.54, 95% CI 0.32 to 0.91; 12 studies, 2050 participants; low-certainty evidence). Effects on mortality weakened when six studies at high risk of bias were excluded from analysis (OR 0.71, 95% CI 0.45 to 1.13; 13 studies, 2046 participants) and in the analysis of submassive PE participants (OR 0.61, 95% CI 0.37 to 1.02; 1993 participants). Effects on recurrence of PE also weakened after removing one study at high risk of bias for sensitivity analysis (OR 0.60, 95% CI 0.35 to 1.04; 11 studies, 1949 participants). We downgraded the certainty of evidence to low because of 'Risk of bias' concerns. Major haemorrhagic events were probably more common in the thrombolytics group than in the control group (OR 2.84, 95% CI 1.92 to 4.20; 15 studies, 2101 participants; moderate-certainty evidence), as were minor haemorrhagic events (OR 2.97, 95% CI 1.66 to 5.30; 13 studies,1757 participants; low-certainty evidence). We downgraded the certainty of the evidence to moderate or low because of 'Risk of bias' concerns and inconsistency. Haemorrhagic stroke may occur more often in the thrombolytics group than in the control group (OR 7.59, 95% CI 1.38 to 41.72; 2 studies, 1091 participants). Limited data indicated that thrombolytics may benefit haemodynamic outcomes, perfusion lung scanning, pulmonary angiogram assessment, echocardiograms, pulmonary hypertension, coagulation parameters, composite clinical outcomes, need for escalation and survival time to a greater extent than heparin alone. However, the heterogeneity of the studies and the small number of participants involved warrant caution when interpreting results. The length of hospital stay was shorter in the thrombolytics group than in the control group (mean difference (MD) -1.40 days, 95% CI -2.69 to -0.11; 5 studies, 368 participants). Haemodynamic decompensation may occur less in the thrombolytics group than in the control group (OR 0.36, 95% CI 0.20 to 0.66; 3 studies, 1157 participants). Quality of life was similar between the two treatment groups. None of the included studies provided data on post-thrombotic syndrome or on cost comparison.

AUTHORS' CONCLUSIONS

Low-certainty evidence suggests that thrombolytics may reduce death following acute pulmonary embolism compared with heparin (the effectiveness was mainly driven by one trial with massive PE). Thrombolytic therapy may be helpful in reducing the recurrence of pulmonary emboli but may cause more major and minor haemorrhagic events, including haemorrhagic stroke. More studies of high methodological quality are needed to assess safety and cost effectiveness of thrombolytic therapy for people with pulmonary embolism.

European Resuscitation Council Guidelines 2021: Adult advanced life support

These European Resuscitation Council Advanced Life Support guidelines, are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the prevention of and ALS treatments for both in-hospital cardiac arrest and out-of-hospital cardiac arrest.

European Resuscitation Council Guidelines 2021: Cardiac arrest in special circumstances

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

Pediatric In-Hospital Cardiac Arrest Secondary to Acute Pulmonary Embolism

OBJECTIVES

Pulmonary embolism is a rarely reported and potentially treatable cause of cardiac arrest in children and adolescents. The objective of this case series is to describe the course of five adolescent patients with in-hospital cardiac arrest secondary to pulmonary embolism.

DESIGN

Case series.

SETTING

Single, large academic children's hospital.

PATIENTS

All patients under the age of 18 years (n = 5) who experienced an in-hospital cardiac arrest due to apparent pulmonary embolism from August 1, 2013, to July 31, 2017.

INTERVENTIONS

All five patients received systemic thrombolytic therapy (IV tissue plasminogen activator) during cardiac arrest or periarrest during ongoing resuscitation efforts.

MEASUREMENTS AND MAIN RESULTS

Five adolescent patients, 15-17 years old, were treated for pulmonary embolism-related cardiac arrests during the study period. These accounted for 6.3% of all children and 25% of adolescents (12-17 yr old) receiving at least 5 minutes of in-hospital cardiopulmonary resuscitation during the study period. All five had venous thromboembolism risk factors. Two patients had known, extensive venous thrombi at the time of cardiac arrest, and one was undergoing angiography at the time of arrest. The diagnoses of pulmonary embolism were based on clinical suspicion, bedside echocardiography (n = 4), and low end-tidal CO2 levels relative to arterial CO2 values (n = 5). IV tissue plasminogen activator was administered during cardiopulmonary resuscitation in three patients and after the return of spontaneous circulation, in the setting of severe hemodynamic instability, in the other two patients. Four of five patients were successfully resuscitated and survived to hospital discharge.

CONCLUSIONS

Pulmonary embolism was recognized as the etiology of multiple adolescent cardiac arrests in this single-center series and may be more common than previously reported. Recognition, high-quality cardiopulmonary resuscitation, and treatment with thrombolytic therapy resulted in survival in four of five patients.

Thrombolytic therapy for pulmonary embolism

BACKGROUND

Thrombolytic therapy is usually reserved for patients with clinically serious or massive pulmonary embolism (PE). Evidence suggests that thrombolytic agents may dissolve blood clots more rapidly than heparin and may reduce the death rate associated with PE. However, there are still concerns about the possible risk of adverse effects of thrombolytic therapy, such as major or minor haemorrhage. This is the third update of the Cochrane review first published in 2006.

OBJECTIVES

To assess the effects of thrombolytic therapy for acute pulmonary embolism.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL databases and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 16 April 2018. We undertook reference checking to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared thrombolytic therapy followed by heparin versus heparin alone, heparin plus placebo, or surgical intervention for patients with acute PE. We did not include trials comparing two different thrombolytic agents or different doses of the same thrombolytic drug.

DATA COLLECTION AND ANALYSIS

Two review authors (JY, QH) assessed the eligibility and quality of trials and extracted data. We calculated effect estimates using the odds ratio (OR) with 95% confidence interval (CI) or the mean difference (MD) with 95% CI. We assessed the quality of the evidence using GRADE criteria.

MAIN RESULTS

We identified no new studies for inclusion in this 2018 update. We included in the review 18 trials with a total of 2197 participants. We were not able to include one study in the meta-analysis because it provided no data that we could extract. Most of the studies carried a high risk of bias because of high or unclear risk related to randomisation and blinding. Meta-analysis showed that, compared with heparin alone, or heparin plus placebo, thrombolytics plus heparin can reduce the odds of death (OR 0.57, 95% CI 0.37 to 0.87, 2167 participants, P = 0.01, low-quality evidence) and recurrence of PE (OR 0.51, 95% CI 0.29 to 0.89, 1898 participants, P = 0.02, low-quality evidence). Effects on mortality weakened when we excluded from analysis four studies at high risk of bias (OR 0.66, 95% CI 0.42 to 1.06, 2054 participants, P = 0.08). The incidence of major and minor haemorrhagic events was higher in the thrombolytics group than in the control group (OR 2.90, 95% CI 1.95 to 4.31, 1897 participants, P < 0.001, low-quality evidence; OR 3.09, 95% CI 1.58 to 6.06, 1553 participants, P = 0.001, very low-quality evidence, respectively). We downgraded the quality of the evidence to low or very low because of design limitations, potential influence of pharmaceutical companies, and small sample sizes. Length of hospital stay (mean difference (MD) -0.89, 95% CI -3.13 to 1.34) and quality of life were similar between the two treatment groups. Limited information from a small number of trials indicated that thrombolytics may improve haemodynamic outcomes, perfusion lung scanning, pulmonary angiogram assessment, echocardiograms, pulmonary hypertension, coagulation parameters, clinical outcomes, and survival time to a greater extent than heparin alone. However, the heterogeneity of the studies and the small number of participants involved warrant caution when results are interpreted. Similarily, fewer participants from the thrombolytics group required escalation of treatment. None of the included studies reported on post-thrombotic syndrome or compared the costs of different treatments.

AUTHORS' CONCLUSIONS

Low-quality evidence suggests that thrombolytics reduce death following acute pulmonary embolism compared with heparin. The included studies used a variety of thrombolytic drugs. Thrombolytic therapy may be helpful in reducing the recurrence of pulmonary emboli but may cause major and minor haemorrhagic events and stroke. More high-quality, blinded randomised controlled trials assessing safety and cost-effectiveness of therapies for pulmonary embolism are required.

Double Bolus Alteplase Therapy during Cardiopulmonary Resuscitation for Cardiac Arrest due to Massive Pulmonary Embolism Guided by Focused Bedside Echocardiography

Massive pulmonary embolism (PE) frequently leads to cardiac arrest (CA) which carries an extremely high mortality rate. Although available, randomized trials have not shown survival benefits from thrombolytic use. Thrombolytics however have been used successfully during resuscitation in clinical practice in multiple case reports and in retrospective studies. Recent resuscitation guidelines recommend using alteplase for PE related CA; however they do not offer a standardized treatment regimen. The most consistently applied approach is an intravenous bolus of 50 mg tissue plasminogen activator (t-PA) early during cardiopulmonary resuscitation (CPR). There is no consensus on the subsequent dosing. We present a case in which two 50 mg boluses of t-PA were administered 20 minutes apart during CPR due to persistent hemodynamic compromise guided by bedside echocardiogram. The patient had an excellent outcome with normalization of cardiac function and no neurologic sequela. This case demonstrates the benefit of utilizing bedside echocardiography to guide administration of a second bolus of alteplase when there is persistent hemodynamic compromise despite achieving return of spontaneous circulation after the initial bolus, and there is evidence of persistent right ventricle dysfunction. Future trials are warranted to help establish guidelines for thrombolytic use in cardiac arrest to maximize safety and efficacy.

Coagulofibrinolytic Changes in Patients with Post-cardiac Arrest Syndrome

Whole-body ischemia and reperfusion due to cardiac arrest and subsequent return of spontaneous circulation constitute post-cardiac arrest syndrome (PCAS), which consists of four syndromes including systemic ischemia/reperfusion responses and post-cardiac arrest brain injury. The major pathophysiologies underlying systemic ischemia/reperfusion responses are systemic inflammatory response syndrome and increased coagulation, leading to disseminated intravascular coagulation (DIC), which clinically manifests as obstruction of microcirculation and multiple organ dysfunction. In particular, thrombotic occlusion in the brain due to DIC, referred to as the "no-reflow phenomenon," may be deeply involved in post-cardiac arrest brain injury, which is the leading cause of mortality in patients with PCAS. Coagulofibrinolytic changes in patients with PCAS are characterized by tissue factor-dependent coagulation, which is accelerated by impaired anticoagulant mechanisms, including antithrombin, protein C, thrombomodulin, and tissue factor pathway inhibitor. Damage-associated molecular patterns (DAMPs) accelerate not only tissue factor-dependent coagulation but also the factor XII- and factor XI-dependent activation of coagulation. Inflammatory cytokines are also involved in these changes via the expression of tissue factor on endothelial cells and monocytes, the inhibition of anticoagulant systems, and the release of neutrophil elastase from neutrophils activated by inflammatory cytokines. Hyperfibrinolysis in the early phase of PCAS is followed by inadequate endogenous fibrinolysis and fibrinolytic shutdown by plasminogen activator inhibitor-1. Moreover, cell-free DNA, which is also a DAMP, plays a pivotal role in the inhibition of fibrinolysis. DIC diagnosis criteria or fibrinolysis markers, including d-dimer and fibrin/fibrinogen degradation products, which are commonly tested in patients and easily accessible, can be used to predict the mortality or neurological outcome of PCAS patients with high accuracy. A number of studies have explored therapy for this unique pathophysiology since the first report on "no-reflow phenomenon" was published roughly 50 years ago. However, the optimum therapeutic strategy focusing on the coagulofibrinolytic changes in cardiac arrest or PCAS patients has not yet been established. The elucidation of more precise pathomechanisms of coagulofibrinolytic changes in PCAS may aid in the development of novel therapeutic targets, leading to an improvement in the outcomes of PCAS patients.

Circulatory collapse, right ventricular dilatation, and alveolar dead space: A triad for the rapid diagnosis of massive pulmonary embolism

A triad of circulatory collapse, right ventricular dilatation, and large alveolar dead space is proposed for the rapid diagnosis and treatment of massive pulmonary embolism. A 17year-old female on oral contraceptives collapsed at home becoming incoherent with shallow breathing. Paramedics initiated mechanical chest compression and transported the patient to our emergency department, arriving minimally responsive with undetectable blood pressure but having positive corneal reflexes and bradycardia with wide QRS. The trachea was intubated and goal-directed echocardiography revealed marked right ventricular dilatation with septal flattening. The arterial PCO₂ was 40mmHg with an end-tidal PCO₂ of 8mmHg, revealing a large alveolar dead space. Persistent hypotension, bradycardia, and fading alertness despite epinephrine and norepinephrine infusions prompted resumption of chest compression. Intravenous alteplase (10mg bolus over 10min followed by 90mg over 110min) begun 125min after collapse improved hemodynamic function within 10min allowing discontinuation of chest compression. Five and a half hours after starting alteplase, the patient was hemodynamically stable and had normal end-tidal PCO₂. A CT-angiogram showed the pulmonary arteries free of emboli but a thrombus in the right common iliac vein. The patient recovered fully and was discharged home on warfarin 8days later. Based on this and other reports, we propose a triad of circulatory collapse, right ventricular dilatation, and large alveolar dead space for the rapid diagnosis and treatment of massive pulmonary embolism, with systemic fibrinolysis as the first-line intervention.

Double Bolus Thrombolysis for Suspected Massive Pulmonary Embolism during Cardiac Arrest

More than 70% of cardiac arrest cases are caused by acute myocardial infarction (AMI) or pulmonary embolism (PE). Although thrombolytic therapy is a recognised therapy for both AMI and PE, its indiscriminate use is not routinely recommended during cardiopulmonary resuscitation (CPR). We present a case describing the successful use of double dose thrombolysis during cardiac arrest caused by pulmonary embolism. Notwithstanding the relative lack of high-level evidence, this case suggests a scenario in which recombinant tissue Plasminogen Activator (rtPA) may be beneficial in cardiac arrest. In addition to the strong clinical suspicion of pulmonary embolism as the causative agent of the patient's cardiac arrest, the extremely low end-tidal CO2 suggested a massive PE. The absence of dilatation of the right heart on subxiphoid ultrasound argued against the diagnosis of PE, but not conclusively so. In the context of the circulatory collapse induced by cardiac arrest, this aspect was relegated in terms of importance. The second dose of rtPA utilised in this case resulted in return of spontaneous circulation (ROSC) and did not result in haemorrhage or an adverse effect.

Breakthrough in cardiac arrest: reports from the 4th Paris International Conference

Jean-Luc Diehl The French Intensive Care Society organized on 5th and 6th June 2014 its 4th "Paris International Conference in Intensive Care", whose principle is to bring together the best international experts on a hot topic in critical care medicine. The 2014 theme was "Breakthrough in cardiac arrest", with many high-quality updates on epidemiology, public health data, pre-hospital and in-ICU cares. The present review includes short summaries of the major presentations, classified into six main chapters: Epidemiology of CA Pre-hospital management Post-resuscitation management: targeted temperature management Post-resuscitation management: optimizing organ perfusion and metabolic parameters Neurological assessment of brain damages Public healthcare.

Thrombolytic therapy for pulmonary embolism

BACKGROUND

Thrombolytic therapy (powerful anticoagulation drugs) is usually reserved for patients with clinically serious or massive pulmonary embolism (PE). Evidence suggests that thrombolytic agents may dissolve blood clots more rapidly than heparin and reduce the death rate associated with PE. However, there are still concerns about the possible risk of adverse effects of thrombolytic therapy, such as major or minor haemorrhages. This is the second update of the Cochrane review first published in 2006.

OBJECTIVES

To assess the effects of thrombolytic therapy in patients with acute pulmonary embolism.

SEARCH METHODS

For this update the Cochrane Vascular Group searched their Specialised Register (last searched September 2014) and the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library (last searched Issue 8, 2014). We also searched individual trial collections and private databases, along with bibliographies of relevant articles. We handsearched relevant medical journals.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that compared thrombolytic therapy followed by heparin versus heparin alone, heparin plus placebo or surgical intervention in patients with acute PE. We did not include trials comparing two different thrombolytic agents or different doses of the same thrombolytic drug.

DATA COLLECTION AND ANALYSIS

Two authors (BD and QH) assessed the eligibility and quality of trials and extracted data.

MAIN RESULTS

We identified 18 trials with a total of 2197 participants for inclusion in the review. We were not able to include one study in the meta-analysis because it had no data to extract. Most of the studies carried a high risk of bias because of high or unclear risk relating to randomisation and blinding. Meta-analysis showed that, compared with heparin alone, or heparin plus placebo, thrombolytics plus heparin can reduce the odds of death (odds ratio (OR) 0.57, 95% confidence interval (CI) 0.37 to 0.87, P = 0.02, low quality evidence) and recurrence of PE (OR 0.51; 95% CI 0.29 to 0.89, P = 0.02, low quality evidence). The effects of death weakened when we excluded four studies at high risk of bias from analysis: OR 0.66, 95% CI 0.42 to 1.06, P = 0.08. The incidence of major and minor haemorrhagic events was higher in the thrombolytics group than in the control group, and this difference was statistically significant (OR 2.90, 95% CI 1.95 to 4.31, P < 0.001, low quality evidence; OR 3.09, 95% CI 1.58 to 6.06, P = 0.001, very low quality evidence, respectively). Length of hospital stay (mean difference (MD) -1.35, 95% CI -4.27 to 1.58) and quality of life were similar between the two treatment groups. Stroke was reported in one study and occurred more often in the thrombolytics group than in the control group, although the confidence interval was wide (OR 12.10, 95% CI 1.57 to 93.39). Limited information from a small number of trials indicated that thrombolytics may improve haemodynamic outcomes, perfusion lung scanning, pulmonary angiogram assessment, echocardiograms, pulmonary hypertension, coagulation parameters, clinical outcomes and survival time to a greater extent than heparin alone. However, the heterogeneity of the studies and small number of participants involved warrant caution when interpreting results. Similarily, fewer patients from the thrombolytics group required escalation of treatment. None of the included studies reported on post-thrombotic syndrome or compared the cost of the different treatments.

AUTHORS' CONCLUSIONS

There is low quality evidence that thrombolytics reduce death following acute pulmonary embolism compared with heparin. Furthermore, thrombolytic therapies included in the review were heterogeneous. Thrombolytic therapy may be helpful in reducing the recurrence of pulmonary emboli but may cause more major and minor haemorrhagic events and stroke. More high quality double blind RCTs assessing safety and cost-effectiveness are required.

Successful alteplase bolus administration for a presumed massive pulmonary embolism during cardiopulmonary resuscitation

OBJECTIVE

To describe the case of a patient successfully resuscitated with bolus alteplase for a presumed massive pulmonary embolism (PE) with associated cardiac arrest.

CASE SUMMARY

A 54-year-old man presented to the emergency department for evaluation of syncope following recent open reduction and internal fixation of his ankle. On arrival, his condition rapidly deteriorated and progressed to cardiopulmonary arrest. Because of noncompliance with postoperative thromboprophylaxis, there was high suspicion for PE. Following 40 minutes of advanced cardiac life support, empirical alteplase 50 mg was administered intravenously over 2 minutes with return of spontaneous circulation (ROSC) observed 6 minutes later. The diagnosis of PE using computed tomographic angiography was confirmed after fibrinolytic therapy. Although his hospital course was complicated by a gastrointestinal bleed requiring transfusion, he was discharged neurologically intact.

DISCUSSION

Clinical guidelines recommend fibrinolytic therapy for patients with PE and cardiac arrest. Data from retrospective analyses, case series, and case reports suggest that various fibrinolytic regimens may facilitate ROSC and improve neurologically intact survival without an increased risk of fatal hemorrhage.

CONCLUSION

The choice of fibrinolytic therapy should be based on hospital availability, with prompt initiation of treatment and incorporation of an intravenous bolus. A reasonable treatment regimen is alteplase 0.6 mg/kg (maximum of 50 mg) or fixed dose of alteplase 50 mg given over 2 to 15 minutes. Resuscitation should be continued for at least 30 minutes, or until ROSC, after fibrinolytic initiation to allow time for the medication to work.

Association of mechanical chest compression and prehospital thrombolysis

Pulmonary embolism (PE) is a common cause of sudden death; the use of prehospital thrombolysis is currently a last-resort option and requires a prolonged cardiopulmonary resuscitation (CPR). Novel mechanical devices have recently been introduced that provides automatic mechanical chest compression (AMCC) according to the guidelines and continually without decrease efficiency throughout prolonged resuscitation. A 54 year-old woman with a history of breast cancer experienced sudden chest pain and severe dyspnea. A mobile intensive care unit was dispatched to her home. During physical examination, she suddenly collapsed with pulseless electrical activity as the initial rhythm. Prehospital thrombolysis during CPR combined with use of AMCC was performed based on a strongly suspected diagnosis of massive PE. After 75 minutes of effective CPR, return of spontaneous circulation was attained. After admission to an intensive care unit, computed tomographic scan confirmed bilateral PE. The patient was discharged 3 weeks after CPR in good neurologic condition. To our knowledge, this is the first case describing combined use of thrombolysis and AMCC in out-ofhospital cardiac arrest. However, for the time being, prehospital thrombolysis in CPR continues to be a measure that should only be performed on a case-by-case basis based on informed decision. Further studies are needed to evaluate the efficacy and safety of AMCC with thrombolysis and thus prolonged CPR.

Successful thrombolytic therapy with recombinant tissue-type plasminogen activator for massive pulmonary embolism -A case report-

Massive pulmonary embolism is associated with significant perioperative morbidity and mortality. We report here on a case of a 69-year-old man who suffered a massive pulmonary embolism with pulseless electrical activity during knee arthroscopic surgery. After a diagnosis was made by performing transthoracic echocardiography, the patient was treated with recombinant tissue-type plasminogen activator. The patient was transferred to the intensive care unit after his hemodynamic status improved. The patient went on to make a full cardiopulmonary recovery without any complications.

Thrombolytic therapy for pulmonary embolism

BACKGROUND

Thrombolytic therapy is usually reserved for patients with clinically serious or massive pulmonary embolism (PE). Evidence suggests that thrombolytic agents may dissolve blood clots more rapidly than heparin and might reduce the death rate associated with PE. However, there are still concerns about the possible risk of adverse effects of thrombolytic therapy, such as major or minor haemorrhages. This is an update of a Cochrane review first published in 2006.

OBJECTIVES

To assess the effectiveness and safety of thrombolytic therapy in patients with acute PE.

SEARCH STRATEGY

For this update the Cochrane Peripheral Vascular Diseases Review Group searched their Specialised Register (last searched April 2009) and the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (last searched Issue 2, 2009). We also searched individual trial collections and private databases, along with bibliographies of relevant articles. Relevant medical journals were handsearched.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that compared thrombolytic therapy with placebo or heparin or surgical intervention in patients with acute PE. We did not include trials comparing two different thrombolytic agents or different doses of the same thrombolytic drug.

DATA COLLECTION AND ANALYSIS

Two authors (DB and WQ) assessed the eligibility and quality of trials and extracted data.

MAIN RESULTS

We included eight trials, with a total of 679 patients, in this review. Results between thrombolytics compared with heparin alone or placebo and heparin were similar in terms of: a) death rate: odds ratio (OR) 0.89; 95% confidence interval (CI) 0.45 to 1.78; b) recurrence of pulmonary embolism: OR 0.63; 95% CI 0.33 to 1.20; c) major haemorrhagic events: OR 1.61; 95% CI 0.91 to 2.86; d) minor haemorrhagic events: OR 1.98; 95% CI 0.68 to 5.75.We found no trials comparing thrombolytic therapy to surgical intervention.Using recombinant tissue-type plasminogen activator (rt-PA) and heparin together compared to heparin alone appeared to reduce the need for further treatment for in-hospital events (OR 0.35; 95% CI 0.17 to 0.71).Thrombolytics improved haemodynamic outcomes, perfusion lung scanning, pulmonary angiogram assessment and echocardiograms to a greater extent than heparin alone.

AUTHORS' CONCLUSIONS

Based on the limited evidence found we cannot conclude whether thrombolytic therapy is better than heparin for pulmonary embolism. More double-blind RCTs, with subgroup analysis of patients presenting with haemodynamically stable acute pulmonary embolism compared to those patients with a haemodynamic unstable condition, are required.

Cerebral resuscitation: state of the art, experimental approaches and clinical perspectives

Neuronal injury following global cerebral ischemia continues to bea central problem of patients in the postresuscitation phase following cardiocirculatory arrest. In addition to measures focusing on rapid restoration of spontaneous circulation, the most effective treatment after cardiac arrest, as shown by large randomized trials,is the use of therapeutic mild hypothermia. Current guidelines of the International Liaison Committee on Resuscitation (ILCOR)are recommending the use of therapeutic mild hypothermia for all unconscious patients after cardiac arrest. At present there is no specific neuroprotective treatment available. Promising animal experimental data concerning the use of thrombolytic agents during cardiopulmonary resuscitation have led to a large European multicenter trial (TROICA trial) that will provide its data in 2006.

Thrombolytic therapy for pulmonary embolism

BACKGROUND

Thrombolytic therapy is usually reserved for patients with clinically serious or massive pulmonary embolism (PE). Evidence suggests that thrombolytic agents may dissolve blood clot more rapidly than heparin and might reduce the death rate associated with PE. However, there are still concerns about the possible risk of adverse effects of thrombolytic therapy, such as major or minor haemorrhages.

OBJECTIVES

To assess the effectiveness and safety of thrombolytic therapy in patients with acute PE.

SEARCH STRATEGY

We sought trials through the Cochrane Peripheral Vascular Diseases Group's Specialised Register (January 18, 2006), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2006), MEDLINE (January 1966 to December 2004), EMBASE, CINAHL, LILACS and SCISEARCH (all November 2004). We also searched individual trial collections and private databases, along with bibliographies of relevant articles. Relevant medical journals were handsearched. The most recent search was on February 6, 2006.

SELECTION CRITERIA

Randomised controlled trials that compared thrombolytic therapy with placebo or heparin or surgical intervention in patients with acute PE. We did not include trials comparing two different thrombolytic agents or different doses of the same thrombolytic drug.

DATA COLLECTION AND ANALYSIS

Two authors (DB and WQ) assessed the eligibility and quality of trials and extracted data.

MAIN RESULTS

Results were similar between thrombolytics compared with heparin alone or placebo and heparin in terms of:a) death rate: odds ratio (OR) 0.89; 95% confidence interval (CI) 0.45 to 1.78; b) recurrence of pulmonary embolism: OR 0.63; 95% CI 0.33 to 1.20;c) major haemorrhagic events: OR 1.61; 95% CI 0.91 to 2.86;d) minor haemorrhagic events: OR 1.98; 95% CI 0.68 to 5.75. We found no trials comparing thrombolytic therapy to surgical intervention. Using recombinant tissue-type plasminogen activator (rt-PA) and heparin together compared to heparin alone appeared to reduce the need for further treatment for in-hospital events (OR 0.35; 95% CI 0.17 to 0.71). Thrombolytics improved haemodynamic outcomes, perfusion lung scanning, pulmonary angiogram assessment and echocardiograms to a greater extent than heparin alone.

AUTHORS' CONCLUSIONS

We cannot conclude whether thrombolytic therapy is better than heparin for pulmonary embolism based on the limited evidence found. More double-blind RCTs, with subgroup analysis of patients presenting with haemodynamically stable acute pulmonary embolism compared to those patients with a haemodynamic unstable condition, are required.

Bolus thrombolytic infusion during prolonged refractory cardiac arrest of undiagnosed cause

Acute myocardial infarction (AMI) and pulmonary embolism (PE) account for about 70% of cardiac arrest. Although thrombolytic therapy is an effective therapy for both AMI and PE, it is not routinely recommended during cardiopulmonary resuscitation (CPR) for fear of life threatening bleeding complications. Numerous case reports and retrospective studies have suggested a beneficial effect of thrombolytics in cardiac arrest secondary to AMI and PE; however, we present a case of successful use of bolus thrombolytics during CPR in a patient with undifferentiated cardiac arrest (undiagnosed cause) after prolonged conventional resuscitation without success.

Fehler und Gefahren der perioperativen Lysetherapie

Until recently, perioperative thrombolysis has always been thought to be a contraindication, because of the risk of bleeding complications. However, many case reports now show that thrombolytic drugs can be successfully used in the perioperative period. Possible indications for perioperative thrombolysis are massive pulmonary embolism and cardiopulmonary resuscitation which are also important causes of cardiac arrest. Thrombolysis can be the decisive therapeutical option, e.g. when normal cardiopulmonary resuscitation measures are not successful. Nevertheless, even against the background of many positive case reports the indication for perioperative thrombolysis should be a case-specific decision as the frequency of complications depends on the surgical intervention and must be weighed against the possible benefits of early thrombolysis. For perioperative thrombolysis there are no data available showing a beneficial effect of one particular therapeutic regimen. In the literature it is suggested that thrombolysis should be performed as quickly as possible, because the risk of bleeding complications depends more on the duration of thrombolysis than on the dosage or the thrombolytic drug itself.

On-scene physician assessment of thromboembolic etiology in out-of-hospital cardiac arrest

Out-of-hospital cardiac arrest (OOHCA) treatment produces dismal recovery rates. Newer, directed therapies such as thrombolysis may be best considered if possible etiologies can be assessed immediately. We conducted a prospective, pilot, feasibility study of on-scene physician assessments in non-traumatic OOHCA. Physicians responded to the scene and reported likelihood of thromboembolic etiology based on detailed history and physical assessments. Included were 136/148 OOHCAs during the 6-month study period; median age was 69.5 years and 72% were men. Physicians judged 103/136 (76%) of arrests to be of thromboembolic etiology and would have recommended thrombolytic bolus in 83/136 (61%). Among 19 instances of physician-reported contraindications, 17 (90%) were not true contraindications. Median age was lower in the group recommended for thrombolysis. Thromboembolic etiology as judged by on-scene physicians was common and physicians recommended thrombolytic bolus commonly. Contraindications were highly overestimated. These data may be useful in the consideration of innovative, directed therapies such as thrombolysis in attempts to improve outcomes from OOHCA.

Successful thrombolysis after pulmonary embolectomy for persistent massive postoperative pulmonary embolism

Massive postoperative pulmonary embolism (PE) is associated with a poor prognosis in patients presenting with haemodynamic instability. Since recent surgery is a commonly accepted contraindication for thrombolytic therapy, pulmonary embolectomy is an appropriate therapeutic approach in these patients. If life-threatening symptoms of PE persist after pulmonary embolectomy, however, very few other therapeutic options are available. We report the successful use of locally administered low-dose thrombolysis 2 days after pulmonary embolectomy in a patient with postoperative PE and persistent severe hypoxaemia and pulmonary hypertension. During and after thrombolysis, no bleeding complications occurred. We conclude that low-dose thrombolysis for PE may be considered even in patients who have recently undergone major thoracic and abdominal surgery if embolectomy and continued intravenous heparin have failed to be successful and life-threatening symptoms of PE persist.

Clinical perspectives and therapeutics of thrombolysis

Reperfusion therapy with thrombolytic agents has been a significant advancement in the management of patients with acute ST elevation myocardial infarction. The outcome of acute myocardial infarction has significantly improved by early application of thrombolytic therapy. Intracoronary streptokinase has been used for >30 years, but reawakening interest occurred in the early 1980s in the use of thrombolytic therapy to establish rapid reperfusion during an acute myocardial infarction. Initial studies aimed at direct intracoronary thrombolysis, but owing to its cumbersome process and requirement of an active round the clock cardiac catheterization laboratory, it has been replaced by regimens of intravenous thrombolytic therapy which is as efficacious as intracoronary administration. Consideration of thrombolytic therapy has become a standard treatment for patients presenting with acute ST elevation myocardial infarction and various well-controlled trials have demonstrated the importance of both early and full reperfusion in improving clinical outcome in the setting of acute myocardial infarction. The subject of intravenous thrombolysis is perhaps the most rapidly evolving area in the management of acute myocardial infarction patients in the past decade. The current review focuses on the thrombolysis in the treatment of myocardial infarction and other conditions.

Tumor Thromboembolism Masquerading as Bland Pulmonary Embolism

Catheter-based interventions provide an important alternative to medical surgical management of massive central pulmonary thromboembolism. Because this option is increasingly being used, it is important to recognize that not all pulmonary thromboemboli are bland. The authors describe two cases in which tumor masqueraded as bland thromboembolism. Identification of tumor thromboembolism may help to alter future work-ups, provide useful prognostic information for a patient, and affect future treatment options.

Safety of thrombolysis during cardiopulmonary resuscitation

The prognosis is generally poor for patients who experience a cardiac arrest. The most common causes of sudden cardiac arrest are massive pulmonary embolism (PE) and acute myocardial infarction (MI). While thrombolysis is a first-line treatment option in massive PE and acute MI, cardiopulmonary resuscitation (CPR) has been regarded as a relative contraindication for thrombolysis because of the anticipated bleeding risk caused by traumatic cardiocompressions. However, an increasing number of case reports and clinical studies on thrombolysis during and after CPR highlight an increased frequency of the return of spontaneous circulation and a better neurological outcome of surviving patients. These effects are mainly due to the thrombolysis of macroscopic blood clots and the amelioration of microcirculatory reperfusion. This article reviews case reports and clinical studies of thrombolysis during and shortly after CPR in order to estimate the risk of severe bleeding events caused by CPR in association with thrombolysis compared with CPR without thrombolysis. Although thrombolysis per se can cause severe and potentially fatal haemorrhage, there is no evidence that severe bleeding events occur more often when thrombolysis is combined with cardiocompressions. In addition, by far the majority of bleeding complications can be treated effectively. Thus, in many cases, the possible benefit of thrombolysis during CPR seems to outweigh the potential risks. However, there may be a publication bias in some case reports and studies towards reporting successful rather than unsuccessful CPRs. In addition, not enough controlled clinical trials have yet been conducted. Therefore, data from large randomised, multicentre studies are needed to definitely answer the question of the relationship between safety and efficacy of this promising treatment option. We conclude that the currently available data do not indicate that thrombolysis contributes to a significant increase in bleeding complications when administered during CPR.

Major bleeding complications in cardiopulmonary resuscitation: the place of thrombolytic therapy in cardiac arrest due to massive pulmonary embolism

OBJECTIVE

Thrombolytic therapy in patients with massive pulmonary embolism (MPE) and prolonged cardiopulmonary resuscitation (CPR) is subject to debate. This study was performed to determine whether (1) thrombolytic treatment increases the risk of bleeding complications, (2) if the risk of bleeding is influenced by the duration of CPR and if (3) thrombolytic therapy improves outcome.

DESIGN

Retrospective cohort study.

SETTING

Emergency department of a tertiary care university hospital.

PATIENTS AND METHODS

Sixty-six patients with cardiac arrest (CA) due to MPE admitted between July 1993 and December 2001. Thirty-six patients received thrombolysis (TL) and were compared with 30 patients without thrombolytic therapy. Bleeding complications were assessed by clinical evidence or autopsy.

RESULTS

Major bleeding complications appear to occur more frequently in patients treated with thrombolytics (9/36 (25%) vs. 3/30 (10%)) even though the difference was statistically not significant (P=0.15). It appears that CPR duration >10 min has no adverse impact on major bleeding complications. No difference in the rate of major bleeding complications between thrombolyzed patients who had a CPR duration of </=10 or >10 min could be observed (2/8 (25%) vs. 7/28 (25%), P=0.99). In thrombolyzed patients a return of spontaneous circulation could be achieved more frequently (24/36 (67%) vs.13/30 (43%) in controls, P=0.06) and survival after 24 h was higher (19/36 (53%) vs. 7/30 (23%), P=0.01). Survival to discharge was also higher in the TL group (7/36 (19%) vs. 2/30 (7%)), but not statistically significant (P=0.15).

CONCLUSION

Although severe bleeding complications tend to occur more frequently in patients undergoing TL, the benefit of this treatment might outweigh the risk of bleeding.

Local and systemic thrombolytic therapy for acute venous thromboembolism

Thrombolytic therapy unquestionably leads to more rapid and complete clot lysis with a significantly higher risk of bleeding when compared with anticoagulation. The most definite indication for thrombolytic therapy in patients with VTE is massive PE associated with hemodynamic instability. Other potential indications, although not widely accepted or proven, include PE-related respiratory failure with severe hypoxemia and massive iliofemoral thrombosis with the risk of phlegmasia cerulea dolens. Routine use of thrombolytic therapy in all other cases of PE and DVT cannot be justified. Future research using randomized controlled studies should focus on the following key questions: Do hemodynamically stable patients with PE and right ventricular dysfunction benefit from thrombolysis, and, if so, is there a subset of patients within this group who are most likely to benefit? Does thrombolytic therapy improve long-term outcomes of DVT with a favorable risk-to-benefit ratio, and, if so, which patients are most likely to benefit long-term? What is the precise role of catheter-directed thrombolysis in the treatment of VTE, particularly the use of a low-dose thrombolytic agent in conjunction with mechanical clot disruption to minimize bleeding in patients at high risk? Until these questions are answered, clinicians must approach decision-making regarding the use of thrombolytic therapy in PE and DVT with careful consideration of the potential risks and benefits for the patient within the framework of currently available data.

Plasminogen activators in inflammation and sepsis

Mortality of severe sepsis remains at 40% to 50%. Intensive efforts over the past two decades have only marginally improved outcome. Improving outcome in sepsis depends on understanding its pathophysiology, which involves triggers, responses of the organism, and dysfunction. Stress, injury, or infection trigger host responses, including local and systemic orchestrated mechanisms. Dysfunction and outcome depend on both trigger and response. Blood coagulation, inflammation, immunity, and fibrinolysis are critical components of the organism's responses. Understanding their role in sepsis pathophysiology is the key to effective treatment. Relevant studies were identified by a systematic literature search, complemented by manual search of individual citations. Using PubMed, 'sepsis' yields more than 62,000 references, 'plasminogen activators' more than 21,000. The selection of citations was guided by preference for reviews that expand important threads of argumentation. Single original studies were included when relevant to critical points. This analytical review describes the essential elements of pathophysiology and the current status of sepsis treatment. Based on this context, an emerging therapeutic option will be discussed: plasminogen activators.

Early intervention in massive pulmonary embolism. A guide to diagnosis and triage for the critical first hour

The diagnosis of massive pulmonary embolism should be considered expeditiously in all patients with unexplained hypotension, syncope, cardiac arrest, or hypoxemic respiratory failure. The presence of right ventricular overload on physical examination or electrocardiogram is an especially important clue. Depending on local expertise and the patient's stability, V/Q scanning, CT angiography, echocardiography, and right heart catheterization can be useful in establishing a diagnosis of pulmonary embolism. Supportive treatment includes oxygen, vasoactive medicines, and sometimes fluids. Although heparin is important in nearly all patients, 70% to 80% of patients also require an IVC filter, thrombolysis, or embolectomy.

Major pulmonary embolism: review of a pathophysiologic approach to the golden hour of hemodynamically significant pulmonary embolism

Major pulmonary embolism (PE) results whenever the combination of embolism size and underlying cardiopulmonary status interact to produce hemodynamic instability. Physical findings and standard data crudely estimate the severity of the embolic event in patients without prior cardiopulmonary disease (CPD) but are unreliable indicators in patients with prior CPD. In either case, the presence of shock defines a threefold to sevenfold increase in mortality, with a majority of deaths occurring within 1 h of presentation. A rapid integration of historical information and physical findings with readily available laboratory data and a structured physiologic approach to diagnosis and resuscitation are necessary for optimal therapeutics in this "golden hour." Echocardiography is ideal because it is transportable, and is capable of differentiating shock states and recognizing the characteristic features of PE. Spiral CT scanning is evolving to replace angiography as a confirmatory study in this population. Thrombolytic therapy is acknowledged as the treatment of choice, with embolectomy reserved for those in whom thrombolysis is contraindicated.

Thrombolysis during cardiopulmonary resuscitation in fulminant pulmonary embolism: a review

OBJECTIVE

To review current knowledge on thrombolysis in patients with fulminant pulmonary embolism (FPE) who need cardiopulmonary resuscitation (CPR).

DATA SOURCES

The bibliography for the study was compiled through a search of different databases between 1966 and 2000. References cited in the articles selected were also reviewed.

STUDY SELECTION

The selection criteria included all reports published on thrombolysis, pulmonary embolism, and CPR, from case reports and case series to controlled studies.

DATA SYNTHESIS

Very few studies evaluated thrombolysis in cases of FPE that required CPR and most of these were clinical case reports and case series with a low level of scientific evidence. There has been no clinical trial to address this issue.

CONCLUSIONS

FPE can frequently produce cardiac arrest, which has an extremely high mortality despite application of the usual CPR measures. The administration of thrombolytic therapy during CPR could help to reduce the mortality, although it has classically been contraindicated. There are no published clinical trials or other high-grade studies that evaluated the efficacy and safety of this approach. From the few existing studies, it can be inferred that thrombolysis may be efficacious and safe for patients with FPE who need CPR. However, a clinical trial is required to provide evidence of value for sound clinical decision-making.

Thrombolysis with recombinant tissue plasminogen activator during cardiopulmonary resuscitation in fulminant pulmonary embolism. A case series

OBJECTIVE

To describe our outcomes using thrombolysis during the cardiopulmonary resuscitation (CPR) of patients in cardiorespiratory arrest (CA) caused by fulminant pulmonary embolism (FPE).

DESIGN

A case series.

SETTING

Intensive care units of a district hospital and a referral centre.

PATIENTS

Six patients that suffered CA secondary to an FPE.

INTERVENTIONS

Administration of recombinant tissue plasminogen activator during usual CPR manoeuvres when there was a strong suspicion of FPE. Permission for the thrombolytic therapy was sought from family members in all cases.

RESULTS

Four out of the six patients survived and remain symptom-free. The thrombolysis was not associated with any fatal complications.

CONCLUSIONS

Early thrombolysis during CPR manoeuvres for CA apparently caused by an FPE may reduce the mortality rate among these patients.

Thrombolytic therapy during cardiopulmonary resuscitation and the role of coagulation activation after cardiac arrest

Thrombolysis is an effective causal therapy for patients suffering from massive pulmonary embolism or acute myocardial infarction. In more than 70% of patients with cardiac arrest, one of these two diseases is the underlying cause of deterioration. Nevertheless, because of the fear of severe bleeding complications, thrombolytic therapy during cardiopulmonary resuscitation (CPR) has been contraindicated. Increasing clinical experience and data from open studies now suggest that thrombolysis during CPR can contribute to hemodynamic stabilization and survival in patients with massive pulmonary embolism and acute myocardial infarction, after conventional CPR procedures have been performed unsuccessfully. After administration of thrombolytic agents, some patients have been stabilized even after more than 90 minutes of CPR. Besides the specific causal action of thrombolytic agents at the site of pulmonary emboli and coronary thrombosis, experimental data indicate that thrombolysis during CPR can improve microcirculatory reperfusion, which may be most important in the brain. In accordance with these data, marked activation of blood coagulation without adequate activation of endogenous fibrinolysis has been demonstrated during reperfusion after cardiac arrest. Massive coagulation activation with subsequent fibrin formation is responsible for microcirculatory reperfusion disorders, and thrombolytic therapy may be indicated. However, no controlled studies are available on this therapeutic concept. Because the risk of bleeding complications is potentially associated with the administration of thrombolytic agents, although this occurs far less than anticipated, thrombolysis during CPR is presently a treatment strategy that can be performed on an individual basis. Whether thrombolysis during CPR can improve survival rates and neurologic outcomes should be addressed in randomized, controlled trials.

Mechanical thrombectomy of major and massive pulmonary embolism with use of the Amplatz thrombectomy device

RATIONALE AND OBJECTIVES

To evaluate the feasibility of mechanical thrombectomy with the Amplatz thrombectomy device (ATD) in restoring patency of acutely thrombosed pulmonary arteries resulting from pulmonary embolism for the improvement of patient outcome.

METHODS

Mechanical thrombectomy with the ATD (8F) was performed in nine consecutive patients with angiographically documented thrombus in the left or right pulmonary artery resulting from deep vein thrombosis (n = 4) or unknown cause (n = 5).

RESULTS

The Miller index decreased from 18 to 11. In all patients, the majority of the thrombus in the pulmonary artery was cleared after a mean activation time of the ATD of 367 seconds. Thrombectomy was performed with the ATD alone (n = 4) or with additional long-term fibrinolysis therapy (n = 5) with infusion of recombinant tissue-type plasminogen activator. Pulmonary arterial pressure decreased from a mean of 57 mm Hg before mechanical thrombectomy to 55 mm Hg directly after the procedure and to 39 mm Hg after termination of the recombinant tissue-type plasminogen activator infusion.

CONCLUSIONS

Mechanical thrombectomy with the ATD in patients with minor and major pulmonary embolism is technically feasible and safe. It is a potential alternative to drug-mediated thrombolysis and surgery. However, the incremental benefit of the ATD over conventional treatments could be shown only in a randomized controlled study.

Efficacy and safety of thrombolytic therapy after initially unsuccessful cardiopulmonary resuscitation: a prospective clinical trial

BACKGROUND

During cardiopulmonary resuscitation (CPR), thrombolysis can help to stabilise patients with pulmonary embolism and myocardial infarction. Moreover, thrombolysis during CPR has beneficial effects on cerebral reperfusion after cardiac arrest. We investigated this new therapeutic approach in patients in whom conventional CPR had been unsuccessful.

METHODS

We assessed, in a prospective study, patients undergoing CPR after out-of-hospital cardiac arrest for cardiological reasons in whom return of spontaneous circulation was not achieved within 15 min. According to the Ustein criteria, our control group consisted of patients who were assessed during 1 year. After this year patients were treated with a bolus of 5000 U of heparin and 50mg, over 2 min, of tissue-type plasminogen activator (rt-PA treated group). This intervention was repeated if return of spontaneous circulation was not achieved within the following 30 min. For controls only CPR was given.

FINDINGS

Overall, 90 patients were included; heparin and rt-PA were given to 40 patients. There were no bleeding complications related to the CPR procedures. Of the rt-PA group, 68% (27) had return of spontaneous circulation and 58% (23) were admitted to a cardiac intensive care unit, compared with 44% (22; p=0.026) and 30% (15; p=0.009) of the controls, respectively. At 24 h after cardiac arrest a larger proportion of the rt-PA group than of the controls was alive (35% [14] vs 22% [11], p=0.171), and 15% (six) of rt-PA-treated patients and 8% (four) of controls could be discharged from hospital.

INTERPRETATION

After initially unsuccessful out-of-hospital CPR, thrombolytic therapy combined with heparin is safe and might improve patient outcome. On the basis of our data a randomised controlled trial might be regarded as ethical.

Biventricular cardiac dysfunction after acute massive pulmonary embolism in the rat

Cardiac dysfunction has been documented in vivo after acute massive pulmonary embolism (AMPE). The present study tests whether intrinsic ventricular dysfunction occurs in rat hearts isolated after AMPE. AMPE was induced in spontaneously breathing ketamine-xylazine-anesthetized rats by thrombus infusion until mean arterial blood pressure (MAP) was approximately 40% of basal measurement. A hypotensive control group underwent controlled blood withdrawal to produce MAP approximately 40% of basal levels. Shams underwent identical surgical and anesthesia preparation but without pulmonary embolization. Hearts were perfused in isovolumetric mode, and simultaneous right ventricular (RV) and left ventricular (LV) pressures were measured. AMPE caused arterial hypotension with hypoxemia (PO(2) = 50 +/- 14 Torr), acidemia (pH = 7.26 +/- 0.11), and high lactate concentration (6.9 +/- 1.7 mM). Starling curves from both ventricles demonstrated that AMPE significantly reduced ex vivo systolic contractile function in the RV (P = 0.031) and LV (P = 0.008) compared with both the hypotensive control and sham hearts. AMPE did not alter coronary flow or compliance in either ventricle. Soluble tumor necrosis factor-alpha decreased in the RV (P = 0.043) and LV (P = 0.005) tissue. These data support the hypothesis that AMPE produces intrinsic biventricular dysfunction and suggest that arterial hypotension is not the principal mechanism of this dysfunction.