Volatile anaesthetic for treatment of respiratory failure from status asthmaticus requiring extracorporeal membrane oxygenation

Inhaled volatile anesthetics in the intensive care unit

The discovery and utilization of volatile anesthetics has significantly transformed surgical practices since their inception in the mid-19th century. Recently, a paradigm shift is observed as volatile anesthetics extend beyond traditional confines of the operating theatres, finding diverse applications in intensive care settings. In the dynamic landscape of intensive care, volatile anesthetics emerge as a promising avenue for addressing complex sedation requirements, managing refractory lung pathologies including acute respiratory distress syndrome and status asthmaticus, conditions of high sedative requirements including burns, high opioid or alcohol use and neurological conditions such as status epilepticus. Volatile anesthetics can be administered through either inhaled route via anesthetic machines/devices or through extracorporeal membrane oxygenation circuitry, providing intensivists with multiple options to tailor therapy. Furthermore, their unique pharmacokinetic profiles render them titratable and empower clinicians to individualize management with heightened accuracy, mitigating risks associated with conventional sedation modalities. Despite the amounting enthusiasm for the use of these therapies, barriers to widespread utilization include expanding equipment availability, staff familiarity and training of safe use. This article delves into the realm of applying inhaled volatile anesthetics in the intensive care unit through discussing their pharmacology, administration considerations in intensive care settings, complication considerations, and listing indications and evidence of the use of volatile anesthetics in the critically ill patient population.

Guidelines for inhaled sedation in the ICU

INTRODUCTION AND OBJECTIVES

Sedation is used in intensive care units (ICU) to improve comfort and tolerance during mechanical ventilation, invasive interventions, and nursing care. In recent years, the use of inhalation anaesthetics for this purpose has increased. Our objective was to obtain and summarise the best evidence on inhaled sedation in adult patients in the ICU, and use this to help physicians choose the most appropriate approach in terms of the impact of sedation on clinical outcomes and the risk-benefit of the chosen strategy.

METHODOLOGY

Given the overall lack of literature and scientific evidence on various aspects of inhaled sedation in the ICU, we decided to use a Delphi method to achieve consensus among a group of 17 expert panellists. The processes was conducted over a 12-month period between 2022 and 2023, and followed the recommendations of the CREDES guidelines.

RESULTS

The results of the Delphi survey form the basis of these 39 recommendations - 23 with a strong consensus and 15 with a weak consensus.

CONCLUSION

The use of inhaled sedation in the ICU is a reliable and appropriate option in a wide variety of clinical scenarios. However, there are numerous aspects of the technique that require further study.

VV-ECMO as bridge and safety net for successful therapeutic polypragmasy in a case of influenza-triggered near-fatal asthma

Key Clinical Message

In near-fatal asthma, the combination of ECMO therapy and isoflurane application via an intensive care ventilator with an anesthetic conservation device represents a therapeutic combination in seemingly hopeless clinical situations.

Abstract

We report a case of an adult patient with near-fatal asthma, who was implanted venovenous extracorporeal membrane oxygenation in an extern hospital before transfer to our tertiary center. After 13 days and various therapeutic approaches, including inhaled isoflurane therapy via an anesthetic-conserving device, the patient was decannulated and extubated 3 days later.

Inhaled volatile anesthetic gas for severe bronchospasm in the emergency department

Bronchospasm is caused by reversible constriction of the smooth muscles of the bronchial tree. This causes obstruction of the lower airways, which is commonly seen at the emergency department (ED) in patients with acute exacerbation of asthma or chronic obstructive pulmonary disease. Ventilation may be difficult in mechanically intubated patients with severe bronchospasm due to airflow limitation, air trapping, and high airway resistance. The beneficial effects of volatile inhaled anesthetic gas had been reported due to its bronchodilation properties. In this case series, we would like to share our experience delivering inhaled volatile anesthetic gas via a conserving device for three patients with refractory bronchospasm at the ED. Inhaled anesthetic gas is safe, feasible and should be considered as an alternative rescue therapy for ventilated patients with severe lower airway obstruction.

Case report: Isoflurane therapy in a case of status asthmaticus requiring extracorporeal membrane oxygenation

Volatile anesthetics have been described as a rescue therapy for patients with refractory status asthmaticus (SA), and the use of isoflurane for this indication has been reported since the 1980s. Much of the literature reports good outcomes when inhaled isoflurane is used as a rescue therapy for patients for refractory SA. Venovenous (VV) extracorporeal membrane oxygenation (ECMO) is a mode of mechanical circulatory support that is usually employed as a potentially lifesaving intervention in patients who have high risk of mortality, primarily for underlying pulmonary pathology. VV ECMO is usually only considered in cases where patients gas exchange cannot be satisfactorily maintained by conventional therapy and mechanical ventilation strategies. We report the novel use of isoflurane delivered systemically as treatment for severe refractory SA in a patient on VV ECMO. A 51-year-old male with a history of asthma was transferred from another institution for management of severe SA. He was intubated at the referring hospital after failing non-invasive ventilation. Initial arterial blood gas (ABG) showed pH 7.21, partial pressure of carbon dioxide (PCO2) >95 mmHg, and partial pressure of oxygen (PaO2) 60 mmHg. VV ECMO was initiated on hospital day (HD) 1 due to refractory respiratory acidosis. After ECMO initiation, acid-base status improved, however, severe bronchospasm persisted and intrinsic positive end expiratory pressure (PEEP) was measured at 18 cm H2O. Systemic paralysis was employed, respiratory rate (RR) was reduced to 4 breaths per minute. This degree of bronchospasm did not allow for ECMO weaning. On HD 5, the patient received systemic isoflurane via the ECMO circuit for 20 h. The following morning, intrinsic PEEP was 4 cm H2O, and wheezing improved. He was decannulated from VV ECMO on HD 10 and extubated on HD 17. Inhaled isoflurane therapy in patients on VV ECMO for refractory SA has shown good results, but requires delivery of the medication via anesthesia ventilators. Our case highlights an effective alternative, systemic delivery of anesthetic via the ECMO circuit, as it is often difficult and dangerous to transport these patients to the operating room (OR) or have an intensive care unit (ICU) room adjusted to accommodate an anesthesia ventilator.

Extracorporeal Life Support for Status Asthmaticus: Early Outcomes in Teens and Young Adults

Extracorporeal life support (ECLS) may be life saving for patients with status asthmaticus (SA), a difficult-to-treat, severe subset of asthma. Contemporary ECLS outcomes for SA in teens and young adults are not well described. The Extracorporeal Life Support Organization (ELSO) Registry was reviewed (2009-2019) for patients (15-35 years) with a primary diagnosis of SA. In-hospital mortality and complications were described. Multivariable logistic regression was used to identify independent risk factors for hospital mortality. Overall, 137 patients, (26 teens and 111 young adults; median age 25 years) were included. Extracorporeal life support utilization for SA sharply increased in 2010, coinciding with increased ECLS utilization overall. Median ECLS duration and length of stay were 97 hours and 11 days, respectively. In-hospital mortality and major complication rates were 10% and 11%, respectively. Nonsurvivors were more likely to have experienced ECLS complications, compared to survivors (86% vs. 42%, p = 0.003). Independent risk factors for in-hospital mortality included pre-ECLS arrest and any renal and/or neurologic complication. Prospective studies designed to evaluate complications and subsequent failure to rescue may help optimize quality improvement efforts.

Intraoperative Management of Adult Patients on Extracorporeal Membrane Oxygenation: An Expert Consensus Statement From the Society of Cardiovascular Anesthesiologists-Part II, Intraoperative Management and Troubleshooting

In the second part of the Society of Cardiovascular Anesthesiologists Extracorporeal Membrane Oxygenation (ECMO) working group expert consensus statement, venoarterial (VA) and venovenous (VV) ECMO management and troubleshooting in the operating room are discussed. Expert consensus statements are provided about intraoperative monitoring, anesthetic drug dosing, and management of intraoperative problems in VA and VV ECMO patients.

Treatment of Acute Severe Asthma Exacerbation with Extracorporeal Membrane Oxygenation and Inhaled Volatile Anesthetic

Severe asthma affects approximately 1-2% of all asthmatic patients. Acute exacerbations are associated with high mortality in this population. There are many treatment options for asthma exacerbation; however, if these treatments fail, patients can develop progressive hypoxia, hypercarbia, respiratory acidosis, and hemodynamic instability. Extracorporeal membrane oxygenation (ECMO) and inhaled anesthetic both have a role in the management of acute severe refractory asthma exacerbation, though there is limited information about the use of both together. We present the case of a patient with severe asthma who suffered a refractory asthma exacerbation and was successfully managed with veno-venous ECMO and inhaled anesthetic. ECMO and inhaled volatile anesthetic both have a role in the management of severe refractory asthma exacerbations. It is safe and beneficial to use these therapies together and more benefit is noted if initiated early in the course of the patient's illness.