Risk of Complications of Atrial Fibrillation

Atrial fibrillation is associated with three major risk of complications: thromboembolism, hemodynamic compromise, and arrhythmogenesis. In patients with chronic atrial fibrillation the incidence of embolization is about 5% per year. The risk of embolism and in particular of stroke can be reduced by warfarine anticoagulation. Aspirin is generally less effective than warfarin, although it is probably more effective than placebo. The hemodynamic complications which may occur during atrial fibrillation are mainly due to the loss of effective atrial contraction, the irregular ventricular rhythm, and the possible excessively rapid ventricular rate. Sudden death is a recognized manifestation of Wolff-Parkinson-White syndrome and is considered to be precipitated by atrial fibrillation in the majority of patients. Torsades de pointes is perhaps the most widely recognized proarrhythmia associated with treatment of atrial fibrillation, especially with 1A antiarrhythmic drugs and sotalol. The chronic treatment with type 1C drugs in 3.5%–5% of patients may induce atrial flutter with 1:1 conduction with significant hemodynamic compromise.     

Successful Catheter Ablation of Reentrant Junctional Tachycardia in a Patient with Asplenia Syndrome before Total Cavo‐Pulmonary Connection

Asplenia syndrome is commonly associated with complex structural cardiac malformations, and junctional tachycardia (JT), which may compromise hemodynamic status, has been reported in association with asplenia syndrome. 1 We report successful radiofrequency catheter ablation of reentrant JT in a patient with asplenia syndrome. (PACE 2010; e43–e45)     

Suspected amniotic fluid embolism following amniotomy: a case report

Amniotic fluid embolism (AFE), also referred to as anaphylactoid syndrome of pregnancy, is a rare obstetric emergency that may manifest itself at any time during pregnancy. AFE is believed to occur when the constituents of amniotic fluid enter the maternal circulation, leading to varying degrees of multiorgan compromise. AFE was first described in 1926, gaining widespread recognition in 1941. This article describes the pathogenesis of AFE, including theories of its immunological mediation available in the literature. The most current diagnostic and treatment modalities are discussed, including several novel therapies. A case report of a 40-year-old parturient who suffered probable AFE following amniotomy, with the development of cardiopulmonary compromise, neurologic involvement, fetal distress, and coagulopathy, is outlined. The patient survived emergency cesarean delivery and hysterectomy with no residual physiologic deficits.     

Vipera Palaestinae Bite and Serum Sickness During Pregnancy

Background: Vipera palaestinae is the most common venomous snake in Israel. We report a case of V. palaestinae bite and antivenom-induced serum sickness during pregnancy and discuss the unique considerations relevant to the treatment of a pregnant woman envenomated by a snake. Case Report: A 46-year-old woman, G6P5, 14 weeks gestation, was admitted after a V. palaestinae bite on her right toe. On admission to the Emergency Department, physical examination included the following vital signs and findings: pulse 76 beats/min, blood pressure 90/60 mm Hg, nausea, vomiting, foot and distal leg swelling, and normal fetal monitoring. She was treated with intravenous fluids, analgesics, and V. palaestinae antivenom. Eight days later she developed serum sickness, was treated with prednisone, and fully recovered. A healthy baby was born at term, with normal examination at 2 months post-delivery. Conclusion: To our knowledge, this is the first reported case of V. palaestinae bite complicated by antivenom-induced serum sickness during pregnancy. No adverse pregnancy outcome due to the antivenom treatment or serum sickness was observed. Careful hemodynamic, hematologic, and obstetric monitoring (including ultrasound) of pregnant snakebite victims is warranted. Antivenom administration should be considered according to published indications to prevent maternal complications and fetal compromise. Patients treated with antivenom should be followed for possible development of serum sickness.     

Cardiorenal syndrome in acute decompensated heart failure

Cardiorenal syndrome (CRS) commonly occurs during treatment of acute decompensated heart failure (ADHF) and is associated with poor clinical outcome. The pathophysiology of CRS entails a complex interaction between hemodynamic alterations, including reduced renal perfusion, increased venous pressure and activation of multiple neurohormonal systems. Attempts to effectively treat congestion while preserving renal function in ADHF are often met with limited clinical success and often require therapeutic decisions that reflect a compromise between potential benefits and harm. At present, there is no evidence-based intervention specifically targeted at renal function. Recent Phase III randomized trials, using novel agents in patients with ADHF, have largely failed to demonstrate any benefits of therapy on renal and clinical outcomes. Early diagnosis of CRS using novel markers of tubular injury may allow for timely interventions and attenuate progression. Future studies are needed to further elucidate the pathophysiology of this complex syndrome and identify new potential targets for effective evidence-based treatments.     

Pneumothorax in patients with acute respiratory distress syndrome: pathophysiology, detection, and treatment

Pneumothorax is a frequent and potentially fatal complication of mechanical ventilation in patients with acute respiratory distress syndrome (ARDS). Prompt recognition and treatment of pneumothoraces is necessary to minimize morbidity and mortality. The radiologic and clinical signs of pneumothoraces in ARDS patients may have unusual and subtle features. Furthermore, small pneumothoraces in these patients can cause severe hemodynamic or pulmonary compromise. Sparse clinical literature exists on when or how to treat pneumothoraces once they develop in patients with ARDS. In this article, the authors review the pathogenesis, radiologic signs, clinical significance, and treatment of pneumothoraces in ARDS patients. Treatment options include traditional tube thoracostomy, open thoracotomy, and image-guided percutaneous catheters.     

Fetal cardiac output, distribution to the placenta and impact of placental compromise.

OBJECTIVES: Intrauterine growth restriction is a common clinical problem, but the underlying hemodynamic changes are not well known. Our aim was to determine the normal distribution of fetal cardiac output to the placenta during the second half of pregnancy, and to assess the changes imposed by growth restriction with various degrees of placental compromise. METHODS: A cross-sectional study of 212 low-risk pregnancies with a gestational age of 18-41 weeks constituted the reference population. A second group of 64 pregnancies with an estimated fetal weight 97.5th percentile, or absent/reversed end-diastolic velocity. Regression analysis and Z-score (SD-score) statistics were used to establish normal ranges and to compare groups. RESULTS: During gestational weeks 18-41 the normal CCO/kg was on average 400 mL/min/kg and the fraction directed to the placenta was on average 32%, while after 32 weeks it was 21%. In intrauterine growth restriction the CCO/kg was not significantly different, but the fraction to the placenta was lower (P < 0.001). This effect was more pronounced in severe placental compromise (P < 0.001). CONCLUSIONS: Normally, one third of the fetal CCO is distributed to the placenta in most of the second half of pregnancy, and one fifth near term. In placental compromise this fraction is reduced while CCO/kg is maintained at normal levels, signifying an increased recirculation of umbilical blood in the fetal body.     

Eculizumab as a bridge to immunosuppressive therapy in severe cold agglutinin disease of anti‐Pr specificity

Severe cold agglutinin disease with hemodynamic compromise requires rapid stabilization of the autoimmune hemolytic anemia as a bridge to the immunosuppressive effect of rituximab. Herein, we describe eculizumab treatment of severe complement‐mediated hemolysis in a patient whose hemodynamic status deteriorated in spite of supportive blood transfusions and therapeutic plasma exchange.     

多普勒超声对双胎输血综合征外周血流变化的研究

双胎输血综合征（ＴＴＴＳ）近年来已越来越引起妇产科临床的关注。本文应用多普勒超声对１１例ＴＴＴＳ胎儿的外周血流进行评价，以探讨两胎儿间不同的血流动力学形式及对妊娠后期危险性预测，结果：１、供、受血儿脐动脉搏动指数（ＰＩ）值明显高于正常组（Ｐ＜０．０１）；２、外周动脉－降主动脉（ＤＡＯ）及大脑中动脉（ＭＣＡ）ＰＩ值和峰值（Ｖｍ）降低（Ｐ＜０．０１）；３、妊娠晚期受血儿充血性心衰加重时脐静脉出现搏动性血流及心内房室瓣返流，结论：外周血流多普勒频谱改变为ＴＴＴＳ的诊断和治疗提供了准确的资料，ＴＴＴＳ胎儿的多普勒超声监测有助于降低围产期死亡率     

A case presentation of Sweet's syndrome and discussion of life-threatening dermatoses

Sweet first described acute febrile neutrophilic dermatosis in 1964. Since then, more than 425 cases of this typically benign, steroid-responsive disease have been recorded. Although often associated with myelodysplastic syndromes or hematologic malignancies, Sweet's syndrome has also been related to pregnancy, autoimmune disorders, and many drug therapies. Although it is not typically an acutely life-threatening illness, there is a potential for significant pulmonary involvement and respiratory compromise. Additionally, emergency physicians should be aware of this unusual disease and its frequent association with systemic illnesses. We report the first case of Sweet's syndrome in the emergency medicine literature and present a review and discussion of several common life-threatening dermatoses.     

Monitorage hémodynamique par échocardiographie des patients en état de choc

Hemodynamic monitoring is necessary in unstable patients with shock, especially in the presence of complex circulatory compromise, high risk of rapid worsening or treatment intolerance. It allows early identification of the main mechanisms leading to shock states, hence helps in guiding adequate and targeted therapeutic interventions, and assesses both the efficacy and tolerance of therapy. Critical care echocardiography is currently recommended as the first-line technique for the hemodynamic assessment of patients presenting with acute circulatory failure. Two complementary approaches may be used. Conventional transthoracic echocardiography is primarily performed and may be completed by the transesophageal approach in the presence of suboptimal imaging quality or if expected diagnostic accuracy is deemed insufficient. If a dedicated training in which modalities have recently been detailed is respected, critical care echocardiography is ideally suited to best determine the type of shock and guide its therapeutic management. Importantly, critical care echocardiography provides additional information when compared with the standard management of patients with septic shock, and this accurately identifies the presence of acute cor pulmonale associated with the acute respiratory distress syndrome and depicts potential sources of imprecision of “blind” hemodynamic monitoring devices, such as the transpulmonary thermodilution. Repeated echocardiographic assessment allows monitoring of both the efficacy an tolerance of therapeutic interventions, including the potential deleterious effects of ventilator settings on right ventricular function in patients sustaining moderate-to-severe acute respiratory distress syndrome. In the near future, the emergence of miniaturized transesophageal echocardiographic probes promises to provide adequate tools for prolonged hemodynamic monitoring using critical care echocardiography in the most unstable patients.     

A Life‐Threatening Flecainide Overdose Treated with Intravenous Fat Emulsion

Flecainide is a Vaughan Williams Class Ic antidysrhythmic associated with PR, QRS, and QTc prolongation on the electrocardiogram and development of life‐threatening cardiac toxicity in overdose. The cornerstone of treatment is fluid resuscitation and the administration of magnesium and sodium bicarbonate. We report a case of flecainide overdose associated with life‐threatening hemodynamic compromise successfully treated with intravenous fat emulsion (IFE) therapy. IFE should be considered as a novel adjunctive therapy in patients with life‐threatening toxicity following flecainide overdose.     

The effects of rhinitis, asthma, and acute respiratory distress syndrome as acute or chronic pulmonary conditions during pregnancy

Pulmonary complications from both obstetrical and non-obstetrical causes contribute to a mortality rate as high as 80% in the pregnant population. The effect of numerous mechanical and biochemical physiologic alterations during pregnancy can influence the maternal and fetal outcomes in a woman with a pulmonary complication. Progesterone, the primary hormone of pregnancy, is a respiratory stimulant that enhances carbon dioxide release and alters the maternal pH in favor of releasing oxygen to the fetus. During systemic compromise, which may be experienced as an acute asthmatic attack or respiratory distress syndrome, desaturation and carbon dioxide retention ensue. Under these conditions, the fetus is at risk for perinatal hypoxemia. Although prompt recognition and treatment are important to minimize maternal, fetal, and neonatal morbidity and mortality, evidence-based literature regarding critical care techniques that promote optimal obstetrical outcomes is limited. Therefore, a collaborative approach to the care of these women is warranted. In addition to critical care, emergency medicine, and obstetrical nurses, the medical team may include an obstetrician, a perinatologist, a neonatologist, a pulmonologist, an intensivist, and an immunologist.     

High-frequency oscillatory ventilation in patients with acute exacerbation of chronic obstructive pulmonary disease

Purpose

High-frequency oscillatory ventilation (HFOV) is usually considered not indicated for treatment of patients with chronic obstructive pulmonary disease (COPD) because of the theoretical risk of air trapping and hyperinflation. The aim of our study was to establish whether HFOV can be safely applied in patients with acute exacerbation of COPD and hypercapnic respiratory failure.

Methods

Ten patients (age, 63-83 years) requiring intensive care treatment who failed on noninvasive ventilation were studied. After initial conventional mechanical ventilation (CMV) of less than 72 hours, all patients were transferred to HFOV for 24 hours and then back to CMV. Arterial blood gases, spirometry, and hemodynamic parameters were repeatedly obtained in all phases of CMV and HFOV at different settings. Regional lung aeration and ventilation were assessed by electrical impedance tomography.

Results

High-frequency oscillatory ventilation was tolerated well; no adverse effects or severe hyperinflation and hemodynamic compromise were observed. Effective CO₂ elimination and oxygenation were achieved. Ventilation was more homogeneously distributed during HFOV than during initial CMV. Higher respiratory system compliance and tidal volume were found during CMV after 24 hours of HFOV.

Conclusions

Our study indicates that short-term HFOV, using lower mean airway pressures than recommended for acute respiratory distress syndrome, appears safe in patients with COPD while securing adequate pulmonary gas exchange.     

Management of familial hypertriglyceridemia during pregnancy with plasma exchange

Hypertriglyceridemia‐induced pancreatitis is a serious complication of familial dyslipidemias. Hormonal influences during pregnancy can compromise otherwise controlled lipid levels in women with familial hypertriglyceridemia and predispose to pancreatitis leading to increased morbidity in both mother and fetus. We report the successful use of therapeutic plasma exchange (TPE) in the management of hypertriglyceridemia during pregnancy resulting in avoidance of pancreatitis and delivery of a healthy term infant. Thirteen TPEs were performed from 19 to 36 weeks gestation to maintain tight control of triglyceride levels. J. Clin. Apheresis, 2009. © 2009 Wiley‐Liss, Inc.     

Calcium entry inhibition during resuscitation from shock attenuates inflammatory lung injury

Trauma and hemorrhagic shock (T/HS) induce a systemic inflammatory response syndrome (SIRS). Neutrophils (polymorphonuclear leukocytes [PMN]) and other cells involved in acute lung injury (ALI) are activated by Ca2+ entry. Thus, inhibiting Ca2+ entry might attenuate post-traumatic lung injury. Inhibiting voltage-operated (L-type) Ca2+ channels during shock could cause cardiovascular collapse, but PMN are "nonexcitable" cells, lack L-type channels, and mobilize Ca2+ via nonspecific channels. We previously showed that PMN Ca2+ entry requires sphingosine 1-phosphate synthesis by sphingosine kinase and that both sphingosine kinase inhibition and blockade of nonspecific channels attenuate ALI when begun before shock. Pretreatment for clinical injuries, however, is impractical. Therefore, we now studied whether Ca2+ entry inhibition that begun during resuscitation from T/HS could attenuate SIRS and ALI without causing hemodynamic compromise. Male Sprague-Dawley rats underwent laparotomy and fixed-pressure shock (mean arterial pressure, 35 +/- 5 mmHg; 90 min). Sphingosine kinase inhibition or nonspecific Ca2+ channel inhibition was begun after resuscitation with 10% of shed blood. We then studied in vivo PMN activation and associated lung injury in the presence or absence of Ca2+ entry inhibition. Neither treatment worsened shock. Each treatment decreased CD11b expression, respiratory burst, PMN p38 MAP-kinase phosphorylation, PMN sequestration, and lung capillary leak in vivo. The similar results seen with two different forms of inhibition strengthen the conclusion that the biological effects seen were specific for calcium entry inhibition. Ca2+ entry inhibition is a candidate therapy for management of lung injury after shock.     

Effects of partial ventilatory support modalities on respiratory function in severe hypoxemic lung injury

OBJECTIVE: The early phase of acute respiratory distress syndrome (ARDS) is characterized by impaired respiratory mechanics, ventilation-perfusion mismatch, and severe hypoxemia. Partial ventilatory support can effectively unload the respiratory workload and improve pulmonary gas exchange with less hemodynamic compromise. The partial ventilatory support mode most indicated in early phases of ARDS has not been determined. This study compares the effects of assisted ventilatory techniques on breathing pattern, gas exchange, hemodynamic function, and respiratory effort with those of controlled mechanical ventilation in similarly sedated subjects. DESIGN: Prospectively randomized crossover animal study. SETTING: Animal research laboratory. SUBJECTS: Eleven anesthetized and mechanically ventilated pigs. INTERVENTIONS: Acute lung injury was induced by lung lavage. Pressure-controlled ventilation (PCV), pressure-controlled assisted ventilation (P-ACV), bilevel positive airway pressure (BIPAP), and pressure support ventilation (PSV) with equal airway pressures and sedation were applied in random order. MEASUREMENTS AND MAIN RESULTS: Gas exchange, respiratory effort, and hemodynamic function were measured, and ventilation-perfusion distributions were calculated by multiple inert-gas-elimination techniques. The results revealed that partial ventilatory support was superior to PCV in maintaining adequate oxygenation and hemodynamic function with reduced sedation. The effects of P-ACV, BIPAP, and PSV were comparable with respect to gas exchange and hemodynamic function, except for a more pronounced reduction in shunt during BIPAP. P-ACV and PSV were superior to BIPAP to reduce respiratory drive and work of breathing. PSV affected the pattern of breathing and deadspace to a greater degree than did P-ACV. CONCLUSIONS: In acute lung injury, P-ACV preserves oxygenation and hemodynamic function with less respiratory effort compared with BIPAP and reduces the need for sedation compared with PCV.     

Transformation of mitral valve prolapse to dynamic left ventricular outflow tract obstruction and back again in a patient with acute transient myocardial depression.

We describe an unusual case of transient resolution of preexisting mitral valve (MV) prolapse during acute cardiac dysfunction and the development of dynamic left ventricular (LV) outflow tract obstruction. The patient presented with lightheadedness, chest pain, and compromised hemodynamic status. Echocardiography revealed akinesis and deformation of the LV anterior wall and apex, hyperdynamic activity in the bases, anterior MV leaflet systolic anterior motion without prolapse, and a dynamic outflow tract gradient. Myocardial function fully recovered over 1 month. Repeat ultrasonography showed posterior MV leaflet prolapse and no anterior MV leaflet systolic anterior motion. Elongated MV leaflets may have contributed to dynamic outflow tract obstruction and life-threatening hemodynamic compromise during LV conformational change.     

Intravenous Adenosine During Atrioventricular Reentrant Tachycardia: Induction of Atrial Fibrillation with Rapid Conduction Over an Accessory Pathway

Adenosine is considered to be a safe agent for termination of orthodromic atrioventricular reentrant tachycardia in patients with accessory pathways. A case with initially successful accessory pathway ablation and without preexcitation during sinus rhythm is presented, in which intravenous adenosine (6 mg) during orthodromic tachycardia was followed by atrial fibrillation and sudden onset of preexcitation with subsequent rapid ventricular response with moderate hemodynamic compromise.     

HELLP syndrome leading to a diagnosis of pregnancy

HELLP syndrome (an acronym for hemolysis, elevated liver enzymes, and low platelets) is a life-threatening complication of pregnancy seen in association with either preeclampsia or eclampsia. HELLP syndrome is rarely diagnosed before 24 weeks of gestation. This atypical form of severe preeclampsia is associated with significant fetal and maternal mortality. The only effective treatment is delivery. We report a case of HELLP syndrome that proved to be a diagnostic clue to an early pregnancy.