Delivering evidence-based critical care for mechanically ventilated patients with COVID-19

As the COVID-19 pandemic has escalated, an unmatched surge of severe cases requiring intensive care unit (ICU) admission has been observed.¹ Currently, more than 50% of patients in the ICU require invasive mechanical ventilation and up to 20% need dialysis. ICU capacity has been increased in many hospitals; however, due to the increased severity of illness,1, 2 even ICUs that are adequately staffed for their usual routine might not have enough trained professionals to deliver the complex care required by ventilated patients with COVID-19-related acute respiratory failure or acute respiratory distress syndrome (ARDS). The challenges can be even greater in developing countries with limited resources. In Brazil, the surge of patients has overwhelmed the health system and worsened the already inadequate access to an ICU bed in a public hospital.

Despite promising results for the antiviral remdesivir,³ no specific and effective treatment exists for the disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Patient care relies mainly on advanced life-sustaining therapies that support organ functions while the immune system controls and eliminates the viral infection.1, 4 The severity of clinical presentations and exceedingly high mortality rates have triggered discussions about the use of traditional adjunctive therapies (eg, corticosteroids) and novel interventions (eg, convalescent plasma infusion), but all lack strong evidence of efficacy and robust safety data in patients with COVID-19.⁴ Improvements in the outcomes of patients with sepsis and non-COVID-19-related ARDS have been achieved by the use of quality-of-care measures to decrease the duration of mechanical ventilation and ICU length of stay, as well as ICU-acquired complications.⁵

The current pandemic is a significant burden on health-care systems worldwide and a strain on their ICUs. Strain can be associated with decreased adherence to the implementation of protocols and evidence-based care measures, and potentially worse patient outcomes.⁶ Thus, it is crucial to focus on protocol implementation and adherence to basic care principles for mechanically ventilated patients.

The severity of COVID-19-associated lung injury can result in long periods of mechanical ventilation and prolonged stay in the ICU. Severe hypoxia can require more aggressive ventilation strategies to improve oxygenation in the short term. Higher tidal volumes (V_T) and driving pressures are more likely to be associated with prolonged ventilation, more profibrotic stimuli due to high V_T in the dysregulated inflammatory response of the lungs, and increased mortality rates.7, 8 In this context, intensivists should aim to reduce the evidence-to-practice gap by implementing lung-protective ventilator strategies and building bedside protocols based on the most recent recommendations, ensuring that V_T lower than 6 mL/kg and plateau pressures of less than 30 cm H₂O are applied.⁹ In severe ARDS, a short course of paralysis and deep sedation might be associated with improved outcomes.¹⁰

Aiming at light sedation strategies should be a goal for most ICU patients, as recommended by recent guidelines.¹¹ The use of deep sedation, even for a short duration, is independently and strongly associated with increased mortality rates for mechanically ventilated patients.¹¹ However, patients with severe COVID-19 might need sedation to avoid asynchrony and improve the application of invasive mechanical ventilation. In elderly patients with COVID-19-related ARDS and increased systemic inflammation, delirium and its complications are likely to develop. Moreover, studies show that in severe cases of COVID-19, SARS-CoV-2 can be identified in the central nervous system, potentially leading to direct brain injury. These factors might contribute to a high incidence of post-intensive care syndrome and decreased quality of life in survivors of COVID-19. Therefore, ICUs should, whenever possible, ensure the use of targeted sedation with strategies to reduce the use of sedatives and benzodiazepines, in order to limit the duration of mechanical ventilation and its associated complications, including the frequency of delirium.¹² The above-mentioned strategies should be applied judiciously, as the increased burden of care in the ICU might unintentionally be associated with a proportional reduction in patient monitoring, which could pose a safety issue in patients under light sedation.

Wise implementation of general preventive measures is of the utmost importance. Patients with COVID-19 present with hypercoagulable states and are particularly prone to vascular thrombosis, including venous thromboembolism (VTE).¹² Ensuring maximal implementation of VTE prophylaxis should thus be a priority goal of care. Hand hygiene and use of masks continue to be fundamental measures to protect patients and staff from nosocomial infections; the use of usual processes of care, such as checklists, before central venous line catheterisation must also be applied. Finally, there is evidence that a combination of evidence-based protocol implementation and multidisciplinary care is associated with improved outcomes and reduced length of stay for mechanically ventilated patients.13, 14 The application of such measures might allow early discharge of patients with COVID-19 and admission of new patients without the investment required to provide additional ICU beds. Optimising the use of scarce resources is even more challenging, but vital, in developing countries, where adherence to low V_T and other process-of-care measures can be suboptimal.¹⁵

Considering the severity and unparalleled number of cases of COVID-19 pneumonia in ICUs, we must ensure the delivery of high-quality care for mechanically ventilated patients (figure ). More than adjunctive treatments or expensive immune therapies, for which evidence of efficacy is lacking, the focus should be on the careful application of evidence-based approaches associated with improved outcomes in ARDS over the past three decades.

Figure.

Effective care measures to improve outcomes in mechanically ventilated patients with COVID-19

ARDS=acute respiratory distress syndrome. ICU=intensive care unit. PPE=personal protective equipment. V_T=tidal volume. VTE=venous thromboembolism. *Must be done if no contraindications are present. †Conservative fluid management is associated with reduced duration of mechanical ventilation.¹⁶