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

Abstract

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.

Keywords: ARDS; COVID-19; ECMO; MODS; SARS-CoV-2; respiratory failure; ventilation.

Fig 1

Three phases of coronavirus disease 2019 (COVID-19). AIP, acute interstitial pneumonitis; AKI, acute kidney injury; APRV, airway pressure release ventilation; ARDS, acute respiratory distress syndrome; COP, cryptogenic organising pneumonia; ECMO, extracorporeal membrane oxygenation; GGO, ground glass opacities; Ino, inhaled nitric oxide; MODS, multiorgan dysfunction syndrome.

Fig 2

Comparison of two typical coronavirus disease 2019 (COVID-19) patients with the Type-L and Type-H phenotypes contrasting chest radiographs, CT, quasi-static pressure-volume loop, gas exchange, and pulmonary mechanics (Pa_o2/Fio₂, Cstat, static lung compliance; C20/Cstat, ratio of static compliance in the last 20% of inspiration to total compliance; LIP, lower inflection point; R/I ratio, recruitment-to-inflation ratio).

Fig 3

Admission CT of three coronavirus disease 2019 (COVID-19) patients requiring retrieval to the severe respiratory failure unit at Guy's and St. Thomas' NHS Foundation Trust after extracorporeal membrane oxygenation implantation at the referring centre. (a) A 44-yr-old male referred after 5 days of invasive ventilation. CT shows classical acute respiratory distress syndrome pattern with diffuse ground glass opacities and dorsal consolidation/atelectasis. Required standard intensive care therapies and no immunomodulation. (b) A 52-yr-old male with CT demonstrating more extensive parenchymal distortion/fibrosis and traction bronchiectasis typical of acute interstitial pneumonitis or Hamman-Rich syndrome after 7 days of invasive ventilation and preceding noninvasive ventilation. Pulsed methylprednisolone (500 mg for 3 days) utilised followed by tapering course. (c) A 32-yr-old male admitted with severe respiratory failure, vasoplegia (norepinephrine 1.7 μg kg⁻¹ min⁻¹), and normal biventricular function related to cytokine release syndrome. Ferritin of 12 000 ng ml⁻¹ and CT appearances of cryptogenic organising pneumonia with occasional reverse halos noted (Atoll sign). Immunomodulation in the form of i.v. immunoglobulin, methylprednisolone 1 mg kg⁻¹ twice daily, and anakinra.

Fig 4

Guy's and St. Thomas' NHS Foundation Trust suggested management of respiratory failure in coronavirus disease 2019 (COVID-19). CRT, critical care response team; ECMO, extracorporeal membrane oxygenation; ED, emergency department; HCID, high consequence infectious disease; HDU, high dependency unit; MERIT, mobile emergency response intubation team; MV, minute ventilation; NRBM, non-re-breather mask; PBW, predicted body weight; RM, recruitment manoeuvre; RR, respiratory rate; Vt, tidal volume; VV-ECMO, venovenous extracorporeal membrane oxygenation.

Fig 5

Anticoagulation strategy in coronavirus disease 2019 (COVID-19). CTPA, CT pulmonary angiogram; DECT, dual energy CT; eGFR, estimated glomerular filtration rate; LMWH, low molecular weight heparin; NTproBNP, N-terminal pro-brain natriuretic peptide; UFH, unfractionated heparin; VTE, venous thromboembolism.