Extracorporeal membrane modality conversions

Not all Shock States Are Created Equal: A Review of the Diagnosis and Management of Septic, Hypovolemic, Cardiogenic, Obstructive, and Distributive Shock

Shock in the critically ill patient is common and associated with poor outcomes. Categories include distributive, hypovolemic, obstructive, and cardiogenic, of which distributive (and usually septic distributive) shock is by far the most common. Clinical history, physical examination, and hemodynamic assessments & monitoring help differentiate these states. Specific management necessitates interventions to correct the triggering etiology as well as ongoing resuscitation to maintain physiologic milieu. One shock state may convert to another and may have an undifferentiated presentation; therefore, continual re-assessment is essential. This review provides guidance for intensivists for management of all shock states based on available scientific evidence.

Drainage From Superior Vena Cava Improves Upper Body Oxygenation in Patients on Femoral Veno-Arterial Extracorporeal Membrane Oxygenation

Objective

To investigate the feasibility of drainage from the superior vena cava (SVC) to improve upper body oxygenation in patients with cardiogenic shock undergoing femoral veno-arterial extracorporeal membrane oxygenation (VA ECMO).

Methods

Seventeen adult patients receiving peripheral femoral VA ECMO for circulatory support were enrolled. The femoral drainage cannula was shifted three times (from the inferior vena cava (IVC) level to the SVC level and then the IVC level again), all under ultrasound guidance, at an interval of 15 minutes. The blood gas levels of the right radial artery (RA) and SVC and cerebral oxygen saturation (ScO₂) were measured and compared.

Results

Fifteen patients (88.2%) were successfully weaned from ECMO, and 12 patients (70.6%) survived to discharge. The oxygen saturation (SO₂) and oxygen partial pressure (PO₂) of the RA (97.0 ± 3.5% to 98.3 ± 1.5%, P < 0.05, SO₂; 127.4 ± 58.2 mmHg to 153.1 ± 67.8 mmHg, P < 0.05, PO₂) and SVC (69.5 ± 9.0% to 75.7 ± 8.5%, P < 0.05, SO₂; 38.5 ± 5.6 mmHg to 43.6 ± 6.4 mmHg, P < 0.05, PO₂) were increased; ScO₂ was also increased on both sides (left: 50.6 ± 8.6% to 55.0 ± 9.0%, P < 0.05; right: 48.7 ± 9.2% to 52.3 ± 9.8%, P < 0.05) when the femoral drainage cannula was shifted from the IVC level to the SVC level. When the femoral drainage cannula was shifted from SVC level to the IVC level again, the SO₂ and PO₂ of RA (98.3 ± 1.5% to 96.9 ± 3.2%, P <0.05, SO₂; 153.1 ± 67.8 mmHg to 125.8 ± 63.3 mmHg, P <0.05, PO₂) and SVC (75.7 ± 38.5% to 70.4 ± 7.6%, P <0.05, SO₂; 43.6 ± 6.4 mmHg to 38.9 ± 4.5 mmHg, P <0.05, PO₂) were decreased; ScO₂ was also reduced on both sides (left: 55.0 ± 9.0% to 50.7 ± 8.2%, P < 0.05; right: 52.3 ± 9.8% to 48.7 ± 9.3%, P <0.05).

Conclusion

Drainage from the SVC by shifting the cannula upward could improve upper body oxygenation in patients with cardiogenic shock undergoing femoral VA ECMO. This cannulation strategy provides an alternative solution for differential hypoxia.

Brain Injury in Extracorporeal Membrane Oxygenation: A Multidisciplinary Approach

Extracorporeal membrane oxygenation (ECMO) represents an established technique to provide temporary cardiac and/or pulmonary support. ECMO, in veno-venous, veno-arterial or in extracorporeal carbon dioxide removal modality, is associated with a high rate of brain injuries. These complications have been reported in 7 to 15% of adults and 20% of neonates, and are associated with poor survival. Thromboembolic events, loss of cerebral autoregulation, alteration of the blood-brain barrier, and hemorrhage related to anticoagulation represent the main causes of severe brain injury during ECMO. The most frequent forms of acute neurological injuries in ECMO patients are intracranial hemorrhage (2-21%), ischemic stroke (2-10%), seizures (2-6%), and hypoxic-ischemic brain injury; brain death may also occur in this population. Other frequent complications are infarction (1-8%) and cerebral edema (2-10%), as well as neuropsychological and psychiatric sequelae, including posttraumatic stress disorder.

Critical Care Management of the Patient With Anaphylaxis: A Concise Definitive Review

OBJECTIVES

Anaphylaxis is a rapidly progressive life-threatening syndrome manifesting as pruritus, urticaria, angioedema, bronchospasm and shock. The goal of this synthetic review is to provide a practical, updated approach to the evaluation and management of this disorder and associated complications.

DATA SOURCES

A MEDLINE search was conducted with the MeSH of anaphylaxis, anaphylactic reaction, anaphylactic shock, refractory anaphylaxis and subheadings of diagnosis, classification, epidemiology, complications and pharmacology. The level of evidence supporting an intervention was evaluated based on the availability of randomized studies, expert opinion, case studies, reviews, practice parameters and other databases (including Cochrane).

STUDY SELECTION

Selected publications describing anaphylaxis, clinical trials, diagnosis, mechanisms, risk factors and management were retrieved (reviews, guidelines, clinical trials, case series) and their bibliographies were also reviewed to identify relevant publications.

DATA EXTRACTION

Data from the relevant publications were reviewed, summarized and the information synthesized.

DATA SYNTHESIS

This is a synthetic review and the data obtained from a literature review was utilized to describe current trends in the diagnosis and management of the patient with anaphylaxis with a special emphasis on newer evolving concepts of anaphylaxis endotypes and phenotypes, management of refractory anaphylaxis in the ICU setting and review of therapeutic options for the elderly patient, or the complicated patient with severe cardiorespiratory complications. Most of the recommendations come from practice parameters, case studies or expert opinions, with a dearth of randomized trials to support specific interventions.

CONCLUSION

Anaphylaxis is a rapidly progressive life-threatening disorder. The critical care physician needs to be familiar with the diagnosis, differential diagnosis, evaluation, and management of anaphylaxis. Skilled intervention in ICUs may be required for the patient with complicated, severe, or refractory anaphylaxis.

Ultrasonographic assessment of aortic flow characteristics in a paediatric patient with sepsis treated with extracorporeal life support: defining the mixing zone

We describe a case of severe sepsis in a 14-year-old boy who was treated with veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) support. The haemodynamic challenges inherent to femoro-femoral VA ECMO are discussed, and the use of ultrasonography to define the location of the mixing zone in the abdominal aorta is demonstrated. We propose that the use of ultrasound is able to assist clinicians in understanding perfusion of abdominal organs in the presence of suspected differential oxygenation.

Extracorporeal membrane oxygenation in trauma: A single institution experience and review of the literature

INTRODUCTION:

Limited options exist for cardiovascular support of the trauma patient in extremis. This patient population offers challenges that are often considered insurmountable. This article identifies a heterogeneous group of trauma patients in extremis who may benefit from extracorporeal membrane oxygenation.

METHODS:

Data were sourced from the medical records of all patients placed on extracorporeal membrane oxygenation following trauma at a Level I Trauma Center between 1 December 2016 and 1 December 2017.

RESULTS:

All patients were male (N = 7), mostly with blunt injuries (n = 5), with an average age of 41 years and with an average Injury Severity Scores of 33 (median = 34). Two out of seven patients survived (28.5%). Survivors tended to have a longer duration on extracorporeal membrane oxygenation (13.5 vs 3.8 days), had extracorporeal membrane oxygenation initiated later (15 vs 7.8 days), and had suffered a blunt injury. Two patients were initiated on veno-arterial extracorporeal membrane oxygenation (both non-survivors) and five were initiated on veno-venous extracorporeal membrane oxygenation (two survivors, three non-survivors). Five patients were heparinized immediately (one survivor, four non-survivors), and two patients were heparinized after clotting was noted in the circuit (one survivor, one non-survivor). Three of the seven (42.8%) patients suffered cardiac arrest either prior to, or during, the initiation of extracorporeal membrane oxygenation (all non-survivors).

DISCUSSION:

Extracorporeal membrane oxygenation use in the trauma patient in extremis is not standard; however, this article demonstrates that extracorporeal membrane oxygenation is feasible in a complex, heterogeneous patient population when treated at designated centers.

Anaphylaxis

Anaphylaxis is a systemic, life-threatening disorder triggered by mediators released by mast cells and basophils activated via allergic (IgE-mediated) or nonallergic (non-IgE-mediated) mechanisms. It is a rapidly evolving, multisystem process involving the integumentary, pulmonary, gastrointestinal, and cardiovascular systems. Anaphylaxis and angioedema are serious disorders that can lead to fatal airway obstruction and culminate in cardiorespiratory arrest, resulting in hypoxemia and/or shock. Often, these disorders can be appropriately managed in an outpatient setting; however, these conditions can be severe enough to warrant evaluation of the patient in the ED and in some cases, hospitalization, and management in an ICU. Reports suggest that underdiagnosis and undertreatment of anaphylaxis are common. Several new syndromes have been described recently including bird-egg, pork-cat, delayed allergy to mammalian meat and a diverse group of mast cell activation disorders. Conditions such as postural orthostatic tachycardia syndrome, carcinoid syndrome, Munchausen stridor, and factitious anaphylaxis can present similarly and need to be included in the differential diagnosis. Anaphylaxis is a clinical diagnosis, but plasma tryptase and urinary histamine levels are often elevated, allowing diagnostic confirmation; however, diagnostic testing should not delay treatment as results may not be immediately available. The sine qua non of treatment is avoidance of any known triggers and epinephrine, which should never be delayed if this disorder is suspected. Secondary treatments include fluids, bronchodilators, antihistamines, and glucocorticoids. Patients with cardiopulmonary arrest or airway or vascular compromise require mechanical ventilation, vasopressors, and other advanced life support in the ICU.

ECMO for intractable status asthmaticus following atracurium

Intraoperative allergic reactions are rare but serious events associated with increased morbidity and mortality. We report the salvage of intraoperative anaphylaxis leading to extreme hypercapnic respiratory failure by veno-venous extracorporeal membrane oxygenation (ECMO). A 38-year-old woman undergoing thyroidectomy developed intractable bronchospasm after administration of atracurium, leading to extreme hypercapnic respiratory failure (PaCO₂ > 250 mmHg, pH 6.773). After the failure of conventional medical therapy and ventilatory optimization, the patient was connected to a veno-venous ECMO circuit. PaCO₂ of 45.6 mmHg and pH of 7.25 were achieved in 1 h, by slowly increasing sweep gas flows up to 3.5 L/min and using continuous end-tidal CO₂ monitoring to gauge the procedure. After extubation and disconnection from ECMO, the patient was discharged on the 6th day without sequelae. Rapid reversal of extreme hypercapnic acidosis by ECMO was feasible, without any neurologic sequelae. Veno-venous ECMO support may be a valuable option for the salvage of intraoperative anaphylaxis.

Successful Rescue of an Adult With Refractory Anaphylactic Shock and Abdominal Compartment Syndrome With Venoarterial Extracorporeal Membrane Oxygenation and Bedside Laparotomy

The incidence of life-threatening anaphylactic reactions related to anesthesia is approximately 1 in 6000 anesthetics administered, and is associated with mortality as high as 5%. In such cases the use of extracorporeal membrane oxygenation (ECMO) in the setting of refractory shock following anaphylaxis may be life saving. Abdominal compartment syndrome (ACS) itself and in this case complicating ECMO support, is a potentially devastating complication of high-volume resuscitation. Decompressive laparotomy is the treatment of choice for ACS. We present a patient treated with venoarterial ECMO for refractory shock following anaphylaxis who developed ACS that was successfully treated with urgent decompressive laparotomy performed in the intensive care unit. This case report highlights the role of abdominal compartment syndrome as a rare but potentially fatal cause of low circuit flow in ECMO-supported patients and proposes a stepwise approach to decision making in this setting. Urgent decompressive laparotomy is potentially lifesaving in this circumstance, and should be urgently considered once other causes of low ECMO flow have been excluded.