Since the first cases of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), were identified in China in December, 2019, we have witnessed increasing numbers of infections and associated deaths worldwide. Although the case fatality rate for SARS-CoV-2 infection (ie, the total number of deaths in patients positive for SARS-CoV-2 divided by the total number of people with a positive test) is not high, given the huge scale of the pandemic, the actual numbers of deaths are considerable.
Three possible characteristics of the dying process in COVID-19 Predominant terminal organ failure
•Terminal respiratory failure: mechanical ventilation and ECMO used•Terminal respiratory failure: mechanical ventilation used, ECMO available but not used
•Terminal respiratory failure: mechanical ventilation used, ECMO not available
•Respiratory failure: mechanical ventilation available but not used
•Respiratory failure: mechanical ventilation hardly or not available•Septic shock, multiple organ failure
•Cardiogenic shock (acute myocardial injury or myocarditis)
•OtherProportionalityof care in the dying process
•Withholding life support: life support available but considered to be disproportionate; life support hardly available (significant constraints)
•Withdrawing life support
•Full care but no cardiopulmonary resuscitation
•Full care including cardiopulmonary resuscitationInvolvementof COVID-19 in the dying process•Death attributed only to COVID-19 (previously healthy, predicted long life expectancy)
•Death primarily due to old age, frailty, or advanced disease (COVID-19 is an epiphenomenon)
•Death due to COVID-19 in an individual with a limited life expectancy
TheLancet Respiratory Medicine, Jason Phua and colleagues1 provide an excellent overview of the current issues raised by COVID-19—in particular, the impact of the disease on intensive care. The Review is clearly and comprehensively written, covering many aspects of the disease, from epidemiology and diagnosis through to intensive care treatment and resource management. One issue raised by this Review is how the reported case fatality rates for patients with COVID-19 can be accurately interpreted.Currently reported case fatality rates vary from 1% to more than 7%,2 but these values must be interpreted with caution. For example, where massive screening has been performed in the whole population (eg, in South Korea and Switzerland), overall case fatality rates of less than 1% have been reported, because the denominator included many mild or asymptomatic cases. However, in countries where only people requiring hospital admission are being screened (eg, Italy and Spain), case fatality rates have exceeded 5%, because the denominator is much smaller.The actual cause of death is also important in interpreting case fatality rates.
Respiratory failure is obviously the main cause,3 as was also the case in previous viral pandemics, such as the Spanish flu of 1918. Today, however, many patients can be supported by invasive mechanical ventilation until the lungs recover. If the situation deteriorates, use of extracorporeal membrane oxygenation (ECMO) systems can control gas exchange for weeks. COVID-19 is sometimes complicated by shock and multiple organ failure,4,5 but the real course of the disease is not yet well described. Knowing that non-survivors are more likely to have low lymphocyte counts or high C-reactive protein or D-dimer levels3,6,7 provides no information about the actual process of death. The precise role of secondary bacterial infections has also not been well defined.Ethical issues also have a relevant role in interpreting case fatality rates, especially when the elderly and frail are more at risk and when resources are stretched so that some form of rationing or triage might become necessary. In such a scenario, differentiating whether the cause of death is specifically due to COVID-19 or the result of treatment limitations can be difficult. Among patients who die before reaching the hospital, some will present too late in the course of the disease to be saved, whereas end-of-life care will be viewed as preferable for others because little chance of survival with a meaningful quality of life exists. In some patients, this decision might be influenced by known individual preferences. Similarly, not all critically ill patients in hospital will be admitted to the intensive care unit (ICU), because the chances of meaningful survival for some will be viewed as too low;8 for these patients, non-invasive ventilation and perhaps even some vasopressor support could be provided in so-called middle care units, but in case of further deterioration, mechanical ventilation will not be considered and death will occur because of severe hypoxaemia. As noted by Phua and colleagues,1 a quarter of patients who died early in the Wuhan, China, outbreak did not receive invasive ventilation.9 Patients who deteriorate despite mechanical ventilation can be placed on resource-intensive ECMO systems (figure).10The decision not to use ECMO might be made because the support system is not available or because such care is considered to be disproportionate in the context of limited staff numbers. The same considerations might apply to patients who develop renal failure. Use of renal replacement therapies is uncommon in those with COVID-19,4,6,7 although acute kidney injury might occur in a third of patients.
Ref Source and Credit : Lancet Respir Med 2020Published OnlineApril 6, 2020 https://doi.org/10.1016/S2213-2600(20)30165-XSee Online/Reviewhttps://doi.org/10.1016/S2213-2600(20)30161-2
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