Mechanical Failure of Extracorporeal Membrane Oxygenation Induced by Hypertriglyceridemia

Congenital Hyperlipidemia in Infants for Congenital Cardiac Surgery

Infants with concurrent severe hypertriglyceridemia and complex congenital heart disease are a rare occurrence and can have life-threatening consequences when undergoing surgical intervention. This case series outlines two instances involving infants undergoing total anomalous pulmonary venous connection repair and surgical closure of a ventricular septal defect. The study explores troubleshooting the effects of hypertriglyceridemia on perioperative outcomes.

The intricate physiology of veno-venous extracorporeal membrane oxygenation: an overview for clinicians

During veno-venous extracorporeal membrane oxygenation (V-V ECMO), blood is drained from the central venous circulation to be oxygenated and decarbonated by an artificial lung. It is then reinfused into the right heart and pulmonary circulation where further gas-exchange occurs. Each of these steps is characterized by a peculiar physiology that this manuscript analyses, with the aim of providing bedside tools for clinical care: we begin by describing the factors that affect the efficiency of blood drainage, such as patient and cannulae position, fluid status, cardiac output and ventilatory strategies. We then dig into the complexity of extracorporeal gas-exchange, with particular reference to the effects of extracorporeal blood-flow (ECBF), fraction of delivered oxygen (FdO2) and sweep gas-flow (SGF) on oxygenation and decarbonation. Subsequently, we focus on the reinfusion of arterialized blood into the right heart, highlighting the effects on recirculation and, more importantly, on right ventricular function. The importance and challenges of haemodynamic monitoring during V-V ECMO are also analysed. Finally, we detail the interdependence between extracorporeal circulation, native lung function and mechanical ventilation in providing adequate arterial blood gases while allowing lung rest. In the absence of evidence-based strategies to care for this particular group of patients, clinical practice is underpinned by a sound knowledge of the intricate physiology of V-V ECMO.

Medical nutrition therapy in patients receiving ECMO: Evidence-based guidance for clinical practice

Patients receiving extracorporeal membrane oxygenation (ECMO) inherit substantial disease-associated metabolic, endocrinologic, and immunologic modifications. Along with the technical components of ECMO, the aforementioned alterations may affect patients' needs and feasibility of adequate macronutrient and micronutrient supply and intake. Thus, patients receiving ECMO are at increased risk for iatrogenic malnutrition and require targeted individual medical nutrition therapy (MNT). However, specific recommendations for MNT in patients receiving ECMO are limited and, with some exceptions, based on an evidence base encompassing general patients who are critically ill. Consequently, clinician decision-making for MNT in patients receiving ECMO is unguided, which may further increase nutrition risk, culminating in iatrogenic malnutrition and ultimately affecting patient outcomes. The purpose of this article is to provide educational background and highlight specific points for MNT in adult patients receiving ECMO, which might serve as evidence-based guidance to develop institutional standard operating procedures and nutrition protocols for daily clinical practice.

Inhaled Sedation for Invasively Ventilated COVID-19 Patients: A Systematic Review

Background: Volatile anesthetics were used as sedative agents in COVID-19 (Coronavirus Disease 2019) invasively ventilated patients for their potentially beneficial pharmacological effects and due to the temporary shortages of intravenous agents during the pandemic crisis. Methods: Online databases (PubMed, EMBASE, The Cochrane Central Register of Controlled Trial) and the “clinicaltrials.gov” website were searched for studies reporting the use of isoflurane, sevoflurane or desflurane. Results: We identified three manuscripts describing the beneficial effects of isoflurane on 41 COVID-19 patients with acute respiratory distress syndrome (ARDS) in Germany (n = 2) and in the USA (n = 1), in terms of reduction in the use of opioids and other sedatives. We also found a case report of two patients with transient nephrogenic diabetes insipidus, which started after 6 and 8 days of sevoflurane sedation. We identified two randomized controlled trials (RCTs; 92 patients overall), two observational studies (238 patients) on the use of volatile anesthetics in COVID-19 patients that were completed but not yet published, and one RCT interrupted for a low recruitment ratio (19 patients) and thus not published. We also identified five ongoing RCTs on the use of inhaled sedation in ARDS, which are also likely to be recruiting COVID-19 patients and which have currently enrolled a total of >1643 patients. Conclusion: Isoflurane was the most frequently used volatile agent in COVID-19 patients and allowed a reduction in the use of other sedative and analgesic drugs. Randomized evidence is building up and will be useful to confirm or challenge these findings.

Comparison of isoflurane and propofol sedation in critically ill COVID-19 patients-a retrospective chart review

Purpose

In this retrospective study, we compared inhaled sedation with isoflurane to intravenous propofol in invasively ventilated COVID-19 patients with ARDS (Acute Respiratory Distress Syndrome).

Methods

Charts of all 20 patients with COVID-19 ARDS admitted to the ICU of a German University Hospital during the first wave of the pandemic between 22/03/2020 and 21/04/2020 were reviewed. Among screened 333 days, isoflurane was used in 97 days, while in 187 days, propofol was used for 12 h or more. The effect and dose of these two sedatives were compared. Mixed sedation days were excluded.

Results

Patients’ age (median [interquartile range]) was 64 (60–68) years. They were invasively ventilated for 36 [21–50] days. End-tidal isoflurane concentrations were high (0.96 ± 0.41 Vol %); multiple linear regression yielded the ratio (isoflurane infusion rate)/(minute ventilation) as the single best predictor. Infusion rates were decreased under ECMO (3.5 ± 1.4 versus 7.1 ± 3.2 ml∙h⁻¹; p < 0.001). In five patients, the maximum recommended dose of propofol of 4 mg∙hour⁻¹∙kg⁻¹ABW was exceeded on several days. On isoflurane compared to propofol days, neuro-muscular blocking agents (NMBAs) were used less frequently (11% versus 21%; p < 0.05), as were co-sedatives (7% versus 31%, p < 0.001); daily opioid doses were lower (720 [720–960] versus 1080 [720–1620] mg morphine equivalents, p < 0.001); and RASS scores indicated deeper levels of sedation (− 4.0 [− 4.0 to − 3.0] versus − 3.0 [− 3.6 to − 2.5]; p < 0.01).

Conclusion

Isoflurane provided sufficient sedation with less NMBAs, less polypharmacy and lower opioid doses compared to propofol. High doses of both drugs were needed in severely ill COVID-19 patients.

Extracorporeal membrane oxygenation in pregnant and postpartum patients: a systematic review

PURPOSE

Information on the use of extracorporeal membrane oxygenation (ECMO) in obstetric patients is scarce. The objective was to conduct a systematic review examining ECMO use in pregnant and postpartum patients in order to identify indications leading to ECMO use and to assess mortality rates.

MATERIALS AND METHODS

PubMed, EMBASE, Cochrane Library, and SCOPUS were searched using the terms "extracorporeal membrane oxygenation" and "pregnancy" up to 1 November 2020. Case reports and case series reporting the use of ECMO in pregnancy were eligible. Data about maternal age, gestational age, diagnosis, type of ECMO, time on ECMO, pregnancy outcomes, and maternal survival were extracted from studies.

RESULTS

The search yielded 1696 citations, of which 125 were included. There were 213 obstetric patients treated with ECMO over a 30-year period. The frequency of reports increased considerably over the last decade. The majority of patients were treated in their third trimester (28.2%) or postpartum (32.9%). Most common etiologies included influenza-induced ARDS (27.7%), pulmonary embolism (13.6%), peripartum cardiomyopathy (11.7%), and infection (11.7%). Pregnancy outcomes ended with live births, either on ECMO (15.5%, 95% CI 10.6-20.4) or not on ECMO (58.3%, 95% CI 51.7-64.9), in fetal demise (8.9%, 95% CI 5.1-12.7), or in spontaneous or induced abortion on ECMO (4.2%, 95% CI 1.5-6.9) or not on ECMO (4.2%, 95% CI 1.5-6.9). Maternal survival was 79.3%.

CONCLUSION

Although women placed on ECMO had a high mortality rate, this is likely an indication of the severity of illness. Overall, ECMO appears to be a valid therapy for the temporary support of vital organs in severely ill pregnant women.

COVID-19-related organ dysfunction and management strategies on the intensive care unit: a narrative review

The coronavirus disease 2019 (COVID-19) pandemic has resulted in a significant surge of critically ill patients and an unprecedented demand on intensive care services. The rapidly evolving understanding of pathogenesis, limited disease specific evidence, and demand-resource imbalances have posed significant challenges for intensive care clinicians. COVID-19 is a complex multisystem inflammatory vasculopathy with a significant mortality implication for those admitted to intensive care. Institutional strategic preparation and meticulous intensive care support are essential to maximising outcomes during the pandemic. The significant mortality variation observed between institutions and internationally, despite a single aetiology and uniform presentation, highlights the potential influence of management strategies on outcome. Given that optimal organ support and adjunctive therapies for COVID-19 have not yet been well defined by trial-based outcomes, strategies are predicated on existing literature and experiential learning. This review outlines the relevant pathophysiology and management strategies for critically ill patients with COVID-19, and shares some of the collective learning accumulated in a high volume severe respiratory failure centre in London.

ECMO Membrane Lung Failure due to Hypertriglyceridemia: A Case Report and Review of the Literature

The deleterious effects of high serum lipid content on the membrane lung (ML) during extracorporeal membrane oxygenation (ECMO) are sparsely documented, and the threshold of lipemia-induced membrane failure is poorly described. We present a case of a patient on venovenous ECMO who developed ML failure after 7 days due to moderate to severe hypertriglyceridemia (700-800 mg/dL). ML failure was exhibited by impaired gas exchange and high transmembrane pressures, and there was notable lipemic layering in the circuit immediately after decannulation. This case demonstrates that in addition to patients with extreme lipemia, ML failure can also occur in patients with moderate to severe hypertriglyceridemia. Hypertriglyceridemia should be suspected in patients with high transmembrane pressures and ML failure not attributable to thrombosis, and these patients may require frequent ML changes if a prolonged ECMO run is required.