Awake Extracorporeal Membrane Oxygenation

Nithya Chowrira Achaiah¹ https://orcid.org/0000-0002-7417-9002, Pooja Natarajan² https://orcid.org/0000-0002-0300-3982, Rajesh Mohan Shetty³, Sanjay Orathi Patangi⁴

^1,3Department of Critical Care Medicine, Manipal Hospital, Whitefield, Bengaluru, Karnataka, India

²Department of Cardiac Anesthesia, Narayana Hrudayalaya, Bengaluru, Karnataka, India

⁴Department of Adult Cardiac Critical Care, Narayana Hrudayalaya, Bengaluru, Karnataka, India

Corresponding Author: Pooja Natarajan, Department of Cardiac Anesthesia, Narayana Hrudayalaya, Bengaluru, Karnataka, India, Phone: +9987158685, e-mail: poo2307@gmail.com

ABSTRACT

Awake extracorporeal membrane oxygenation (ECMO) is a new concept that is evolving in the current day scenario of intensive care practice worldwide. It is indeed a phenomenal initiative towards early mobilization of patients, despite being on cardiopulmonary/pulmonary assist devices attached to the patients. This has prevented many complications associated with long stays in hospitals as well as cost-saving practices. Although awake ECMO has its own pros and cons and poses lot many challenges to the intensivists, nevertheless it has been shown to benefit patients and reduce morbidity. In this submission, we are describing two representative cases of awake ECMO: the first one is a patient with COVID-19- induced acute respiratory distress syndrome with venovenous ECMO and the other patient is a post-pulmonary endarterectomy patient on venoarterial ECMO for refractory ventricular tachycardia. These two cases illustrate not only the feasibility but also the successful outcome of awake ECMO.

How to cite this article: Achaiah NC, Natarajan P, Shetty RM, et al. Awake Extracorporeal Membrane Oxygenation. J Acute Care 2022;1(1):32-34.

Source of support: Nil

Conflict of interest: None

Keywords: Awake ECMO, COVID-19 ARDS, Pulmonary endarterectomy

INTRODUCTION

Extracorporeal life support (ECLS) is a technology that includes extracorporeal membrane oxygenation (ECMO). ECMO is a lifesaving measure that provides support to the failing heart, lungs or both in critically ill patients who present with cardiac/pulmonary/combined cardiopulmonary failure. The patients chosen for this advanced form of therapy are the sickest of the lot who haven’t responded to conventional therapy. The stay of such patients in the critical care unit is marked by a prolonged intensive care unit (ICU) stay and extensive rehabilitation. In recent years, there has been a significant interest in having these patients breathe spontaneously and mobilized, the so-called “awake ECMO.” The ‘awake ECMO’ initiative can reduce the critical illness neuropathy, improve functional recovery, reduce superadded infections/bedsores and length of stay in the hospital, thus decreasing the cost of treatment, despite the fact that management of an awake patient on ECMO may pose its own challenges. Here we present two representative cases to highlight the advantages and feasibility of awake ECMO in critical care units.

Case 1

A 59-year-old gentleman with past history of hypertension was admitted to a tertiary care hospital with a history of fever for 2 days. The result of the oropharyngeal swab taken at the time of admission was positive for SARS CoV-2 real-time reverse transcription-polymerase chain reaction. Within 24 hours of admission, he became hypoxic requiring administration of oxygen. His chest radiograph was consistent with COVID-19 pneumonia (Fig. 1). He was administered oxygen through a high-flow nasal cannula (HFNC) followed by noninvasive ventilation (NIV) in view of worsening respiratory distress and hypoxia was commenced. On day 7, he required endotracheal intubation, due to further worsening and he was initiated on lung-protective ventilation. His oxygenation continued to deteriorate despite high positive end-expiratory pressure (PEEP), deep sedation, and neuromuscular blockade, hence he was pronely ventilated. As he continued to be hypoxic and hypercapnic, venovenous extracorporeal membrane oxygenation (VV-ECMO) support was commenced. At the time of this decision, his potential of hydrogen (pH) was 7.07, partial pressure of oxygen/fraction of inspired oxygen (PaO₂/FiO₂) ratio was 111 on 85% oxygen with a PEEP of 12 cmH₂O and partial pressure of carbon-di-oxide was 87 mm Hg. ECMO was initiated after cannulating the right internal jugular vein (IJV) with a 19 Fr inflow cannula and the right femoral vein was cannulated with a 25 Fr drainage cannula using the Seldinger technique. The ventilation was reduced to rest settings with PEEP of 10 cmH₂O, and respiratory rate of 8/min targeting plateau pressure less than 20 cmH₂O. The initial ECMO settings were–a sweep gas flow of 6L/min with blood flow of 3.8–4 L/min. On the third-day post ECMO, he was extubated onto HFNC. The patient was conscious, breathing on his own, and comfortable. His oxygenation and pulmonary function improved over the next couple of days. Weaning from ECMO was achieved with a gradual reduction in sweep gas flow. He was put on NIV and weaned off ECMO and decannulated on the 56th-day post-initiation of ECMO. He made an uneventful recovery then onward. The high-resolution CT (HRCT) done 5 days prior to discharge showed clearing of the patchy consolidations with features suggestive of fibrosis and traction bronchiectasis (Fig. 1B).

Figs 1A and B: (A) HRCT thorax with Severity Score (CTSS) of 25/25 and pneumomediastinum, (B) HRCT thorax done 5 days prior to discharge showed clearing of the patchy consolidations with features suggestive of fibrosis and traction bronchiectasis

Case 2

We present a case of a 22-year young lady with a history of breathlessness, hemoptysis, and deep vein thrombosis in the lower limbs, for the past 1 year and diagnosed with chronic thromboembolic pulmonary artery hypertension and underwent pulmonary thromboendarterectomy. On the day preceding surgery, the electrocardiography showed a right ventricular (RV) strain pattern with RV hypertrophy. Intraoperatively, a high clot burden was encountered and the surgery was performed on deep hypothermic circulatory arrest uneventfully (Fig. 2). On arrival at the ICU, the pulmonary artery pressure was 38/21(27) mm Hg with a pulmonary vascular resistance of 153 dynes/sec/cm-5. The patient was on minimal inotropic support of dopamine 3mic/kg/min and milrinone 0.5 mic/kg/min, with a PaO2/FiO2 ratio of >200. Although the X-ray showed reperfusion injury, as expected due to the heavy clot burden, nevertheless the oxygenation was not hampered (Fig. 3A). After 8 hours patient developed repeated runs of pulseless ventricular tachycardia not responding to amiodarone/lignocaine/defibrillation. Central venoarterial (VA) ECMO was initiated to provide cardiopulmonary support in view of hemodynamic compromise. As the patient became stable on ECMO, she was extubated on POD2. She was comfortable breathing spontaneously and cooperated with physiotherapy and ambulation enough to sit on a bedside chair. However, the right lung developed “white-out” on POD 5 on ECMO (Fig. 3B), and the computed tomography of the lung revealed a complete occlusion with mucous plugs of the right bronchus from the carina. This was immediately followed by bronchoscopy and the airway was cleared (Fig. 3C). The patient was weaned off ECMO and decannulated on the 6th POD. She recovered fully and was discharged in a fit condition on the 16th POD.

Fig. 2: Specimen of pulmonary endarterectomy

Figs 3A to C: (A) X-ray showing reperfusion injury of the lung, (B) X-ray on ECMO showing white-out of the right lung, (C) X-ray of lung cleared after bronchoscopy and retrieval of clots

DISCUSSION

In this submission, we are describing two representative cases of awake ECMO: the first one is a VV-ECMO and the other being a VA-ECMO. These two cases illustrate not only the feasibility but also the successful outcome of awake ECMO. Active physiotherapy and prompt mobilization of critically ill patients are being increasingly realized as a safe and feasible means of optimizing outcomes in the intensive care units. With the increasing popularity and rapidly expanding use of ECLS for severe cardiac, respiratory or cardiopulmonary failure, there is a growing interest in the institution of early mobilization to this patient population; this has been shown to be safe and feasible in select patient populations. However, some patients receiving ECMO support may benefit from early mobilization more than others. Early ambulation and mobilization are particularly beneficial in those awaiting heart or lung transplantation: maintenance of physical conditioning plays an important role in deciding on the suitability of the patient for transplantation. The ability to engage critically ill patients in active physical therapy and early mobilization necessarily involves minimization of sedation and is often further facilitated by a strategy that favors endotracheal extubation.¹ Strategy which includes the patient being awake, mobile, or spontaneously breathing can be incorporated, based on the extent of ECMO support required or the severity of the disease. Based on which method works best, is a clinical judgment call made by the team members who are involved with patient care and there is a learning curve to it. Awake ECMO and early extubation may be practiced to prevent the complications associated with mechanical ventilation.² Spontaneous respiration preserves the tone of the respiratory muscles and prevents atelectasis. Minimal use of sedation reduces the incidence of delirium. Awake patients can actively collaborate with the physiotherapists and perform rehabilitations which also reduce loss of muscle mass and critical illness-induced neuromuscular weakness. Early mobilization maybe is particularly useful in patients who require ECMO for a long duration.³ Interactions with family/friends and medical personnel are likely to render the unfriendly ICU environment into a congenial atmosphere that enhances the recovery and feeling of well-being. The patient can also communicate his symptoms with the medical staff which helps in providing better treatment. However, there are disadvantages like spontaneous ventilation-induced lung injury, patient anxiety, pain, displacement of cannula, and disturbances in ECMO flow which should be borne in mind.⁴^-⁶

These two case reports highlight the potentiality and safety of ‘awake’ ECMO in different scenarios namely in VV-ECMO in patients with severe COVID-19 pneumonia and another with severe cardiopulmonary compromise following PTE.

CONCLUSION

Awake ECMO and early extubation should be considered in patients who have been stabilized on ECMO especially those without multisystem involvement along with strict infection control practices and continuation of ECMO support until the primary disease is resolved.

ORCID

Nithya Chowrira Achaiah https://orcid.org/0000-0002-7417-9002

Pooja Natarajan https://orcid.org/0000-0002-0300-3982

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