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Management of pandemic critical illness 

Management of pandemic critical illness
Chapter:
Management of pandemic critical illness
Author(s):

Robert Fowler

and Abhijit Duggal

DOI:
10.1093/med/9780199600830.003.0009
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date: 27 February 2020

Key points

  • Pandemic preparedness hinges on the development of appropriately trained staff with well-defined roles.

  • A goal of pandemic planning should be to have the ability to manage surge in the number of patients with optimal use of available resources throughout the duration of the disease outbreak.

  • A rigorous infection control programme for pandemics should be built upon the existing infection prevention and control practices of the hospital, and based upon modes of transmission for known or suspected agents.

  • Triage protocols should be based on equitable distribution of resources and on ethical principles of justice, beneficence, and non-maleficence.

  • Research preparedness, with approved protocols, electronic case report forms, and harmonized clinical trials databases afford the best chance at early accurate pandemic descriptive and interventional studies.

Defining pandemics

The World Health Organization (WHO) defines a disease outbreak as ‘the occurrence of new cases of a disease process in excess of what is expected in a defined community, geographical area or season’ [1]‌. An outbreak becomes a pandemic if it extends over several countries over a defined period of time, which may be limited to days, weeks, or even years [1]. Unfortunately, pandemic preparedness is based on assumptions, and these cannot account for the uncertainty associated with the nature, magnitude, or timing of these disease outbreaks.

Adequate and appropriate provision of critical care services during pandemics may dramatically alter vital outcomes of patients who develop acute respiratory distress syndrome (ARDS) and critical illness. As a consequence of the 1918–1920 global H1N1 influenza pandemic, it is estimated that approximately 50 million people—3% of the world’s population—died [2]‌. Today, these patients would be admitted to intensive care units (ICUs) and it is likely that the majority would survive. Indeed, the provision of critical care during the severe acute respiratory syndrome (SARS) outbreak and 2009 H1N1 pandemic had a substantial impact on the survival of the sickest patients [3,4,5].

However, SARS and the 2009 H1N1 pandemic also highlighted the limited capacity for increased provision of critical care, even in well-resourced settings, and the potential for dramatic differences in mortality in under-resourced settings [3]‌. Thus, pandemic preparedness planning must focus on the most effective utilization of available resources in times of increased need. During the SARS outbreak in particular, we were taught difficult lessons about how inadequate preparation exacerbates shortages in technical capacity and personnel, and can lead to increased risk of illness transmission, the provision of ineffective and potentially harmful therapies, and a research response that is too slow to inform patient care [5,6]. This chapter will focus upon pandemic preparedness, as well as rapid clinical, education, and research responses.

Pandemic preparedness and mitigation

Intensivists frequently are among the first to recognize the most severe presentation of severe respiratory outbreaks. Accordingly, intensivists not only help develop treatment options, but are also intimately involved with developing the case definitions, determining early case fatality rates, transmission prevention, and the challenging task of informing potential triage decisions if demand exceeds capacity.

Pandemic preparedness hinges on the development of appropriately trained staff with well-defined roles in the event of a pandemic [7]‌. The lack of an organizational structure, and the absence of command and communication have been recognized as key factors in failure to provide appropriate medical services in previous mass casualty events and disease outbreaks [8]. Therefore, newer models focus on defining clearer roles for the individuals involved in pandemic response with a clear line of communication between health systems, and the local and federal authorities [7,8]. The response and preparedness model for disease outbreaks borrows heavily from the incident management system concept [8]. Government authorities in conjunction with health care personnel have developed standard operating procedures for responders during an outbreak using this model [8]. Emphasis is also placed on staff education and regular training to ensure readiness in the event of an outbreak [7].

Systems surge capacity

Pandemics often present with a sudden increase in patients requiring critical care services. [7,8]. The need for resources is variable, and is dependent on geographical and temporal factors. Pandemic surges typically come in multiple waves, lasting weeks or months at a time, separated by months, and potentially lasting for years [7,9] (see Fig. 9.1) Facilities should be equipped to provide emergency mass critical care (EMCC) services with an ability for a phased expansion to at least double the capacity for critical care beds during a pandemic (Fig. 9.2a, b). However, the scalar is critically dependent upon baseline capacity and the nature of the pandemic, and it is, therefore, impossible to prescribe for a given ICU [7,8]. Increasing ICU needs should also be balanced with other hospitals services—there is a potential for decreasing benefit with a unilateral increase in ICU capacity because of the excess demands on the available resources and health care providers [8]‌.

Fig. 9.1 Three waves: combined influenza and pneumonia mortality associated with the three waves of the 1918–1919 influenza pandemic in the United Kingdom.

Fig. 9.1 Three waves: combined influenza and pneumonia mortality associated with the three waves of the 1918–1919 influenza pandemic in the United Kingdom.

Reproduced from Taubenberger JK, Morens DM, 1918 ‘Influenza: the mother of all pandemics’, Emerging Infectious Diseases, 12(1), pp. 15–22, 2006, with permission from Centers for Disease Control and Prevention. Data from Jordan E. Epidemic influenza: a survey. Chicago: American Medical Association, 1927.

Fig. 9.2 (a) Initial expansion of critical care treatment space during disasters requires expansion into intermediate care units and telemetry spaces. Intermediate care and telemetry patients should be moved to general practice wards. The least sick patients should be discharged or transferred to community care facilities. (b) Expansion of critical care services in sustained catastrophes involves the transfer of all remaining intermediate care and telemetry patients to general hospital wards. Most, if not all, lower-acuity patients on the wards will need to be moved out of the hospital. Critical care patients will now occupy most of the hospital, including some of the general hospital wards.
Fig. 9.2 (a) Initial expansion of critical care treatment space during disasters requires expansion into intermediate care units and telemetry spaces. Intermediate care and telemetry patients should be moved to general practice wards. The least sick patients should be discharged or transferred to community care facilities. (b) Expansion of critical care services in sustained catastrophes involves the transfer of all remaining intermediate care and telemetry patients to general hospital wards. Most, if not all, lower-acuity patients on the wards will need to be moved out of the hospital. Critical care patients will now occupy most of the hospital, including some of the general hospital wards.

Fig. 9.2 (a) Initial expansion of critical care treatment space during disasters requires expansion into intermediate care units and telemetry spaces. Intermediate care and telemetry patients should be moved to general practice wards. The least sick patients should be discharged or transferred to community care facilities. (b) Expansion of critical care services in sustained catastrophes involves the transfer of all remaining intermediate care and telemetry patients to general hospital wards. Most, if not all, lower-acuity patients on the wards will need to be moved out of the hospital. Critical care patients will now occupy most of the hospital, including some of the general hospital wards.

ICU, intensive care unit; PACU, post-anaesthesia care unit; ED, emergency department; IMCU, intermediate care unit.

Reproduced with permission from the American College of Chest Physicians. Rubinson L et al., ‘Definitive care for the critically ill during a disaster: medical resources for surge capacity: from a Task Force for Mass Critical Care Summit Meeting, January 26–27, 2007. Chicago, IL’, Chest, 133(5 Suppl.), 32S–50S. American College of Chest Physicians.

Critical care staffing

Providing health care during a disaster is stressful and caregivers are at a significant risk of developing compassion fatigue, post-traumatic stress, and anxiety disorders. This results in decreased productivity and team functioning [8,10]. In most cases, there will be a need for expanded roles of non-critical care staff in specific areas in the ICU [10,11]. Members of the health care team from certain acute care areas (for example, post-anaesthetic care units, etc.) might play an important role in helping to care for critically ill patients. A mix of skilled critical care practitioners supervising less experienced health care workers in specified geographical areas may also be effective in pandemic situations [10,11]. Another strategy is to introduce a phased staffing plan where the working hours of care teams are staggered, to overlap individuals from different care teams. This approach is associated with lower rates of fatigue and helps the overall morale of the care team [10].

Infection control

Health care workers and patients are extremely vulnerable to nosocomial transmission of infectious agents during pandemics [10]. A rigorous infection control programme for pandemics should be built upon the existing infection prevention and control practices of the hospital, and based upon modes of transmission for known or suspected agents [12,13]. Infected and exposed patients should generally be physically separated from other hospitalized patients who are susceptible to infection. It is prudent to initiate contact, droplet, and airborne precautions in uncertain pandemic situations and de-escalate accordingly when a fuller understanding of the illness becomes available [12]. Airborne precautions should be instituted for specific pathogens or during certain aerosol generating procedures (see Table 9.1) [12,13,14].

Table 9.1 Different levels of precautions in viral outbreaks [12, 13]

Pandemic H1N1 influenza

SARS

Avian influenza

Seasonal influenza

Level of Precaution

Contact and droplet

Contact, droplet, and airborne

Contact and droplet

Contact and droplet

Duration of infection-control precautions*

5–10 days after onset of symptoms

While the patients are symptomatic

2–3 weeks after onset of symptoms

5–10 days after onset of symptoms

Contact precautions and droplet precautions

Personnel protective equipment

Gowns, gloves, and eye protection

Gowns, gloves, and eye protection

Gowns, gloves, and eye protection

Gowns, gloves, and eye protection

Masks

Either surgical masks, or N-95 or equivalent masks

N-95 masks, or powered air purifying respirator

Either surgical masks or N-95 masks or equivalent masks

Either surgical masks or N-95 or equivalent masks

Airborne precautions

Environmental Precautions

Dedicated patient care equipment, private patient room if possible, limit patient transport

Dedicated patient care equipment, private patient room if possible, limit patient transport, negative isolation room, >12 air exchanges/hour through monitored HEPA systems

Dedicated patient care equipment, private patient room if possible, limit patient transport, negative isolation room, >12 air exchanges/hour through monitored HEPA systems

Dedicated patient care equipment, private patient room if possible, limit patient transport

Incubation period*

1–7 days

1–7 days

1–17 days

1–7 days

* Periods are approximate, and may be longer or shorter for certain patients.

SARS, severe acute respiratory syndrome; HEPA, high-efficiency particulate air.

Data from various sources (see references).

Health care personnel should receive training in infection control procedures including the need for hand washing, and the implementation of isolation procedures, etc. [12,13,14]. These personnel should also be trained in the pre-outbreak or inter-pandemic in the use of personal protective equipment, and training such as fit testing for masks, and the use of gloves and gowns in pandemic situations updated and documented regularly [12,13,14]. Aerosol generating procedures, such as high frequency oscillatory ventilation, non-invasive ventilation, and bronchoscopy, may increase the risk of virus transmission, but there is limited data to implicate particular modes of ventilation, and application of any of these modes may be reasonable, with appropriate health care worker precautions [13,14]. Negative pressure airborne isolation rooms, and high efficiency particulate air (HEPA) filter machines could be considered during procedures such as non-invasive ventilation, high frequency oscillation, etc., but their effectiveness in decreasing transmission rates is still unclear [13,14].

Resource allocation

Pandemic care needs to address the potential for a necessary increase in essential equipment (see Table 9.2) for both the patients admitted as a result of the pandemic, and patients admitted due to other medical problems [7,8,11] A model of a single pool of resources to be accessed by all in a designated health facility is likely to be more effective than numerous stockpiles in various departments [7,11]. Hospitals should establish a pandemic management committee, with representation by personnel from clinical, laboratory, and ancillary health care and administrative departments. Such a group should meet face-to-face on a daily-to-weekly basis to establish effective means of information gathering and dissemination within their area. Ideally, there should be similar local state and national acute care, and public health and governmental communication and coordination of resource allocation. During SARS and H1N1, we learnt that it is common for hospitals, cities, and countries to be differentially affected, and for certain regions to be stretched beyond capacity, while others had yet to experience substantially increased caseloads. A pre-established state and national mechanism to share resources (personnel, ventilators, medication, infection prevention, and control equipment) from small regional stockpiles or from a pre-existing inventory is essential.

Table 9.2 Equipment and devices to consider during viral respiratory illness pandemics

Essential medical equipment

  • Respiratory support equipment including mechanical ventilators

  • Peripheral, central venous, and arterial catheters for haemodynamic support

  • Monitoring equipment

Pharmacologic therapies

  • Antivirals: neuraminidase inhibitors specifically for influenza outbreaks

  • Antibiotics: for community-acquired pneumonia, secondary bacterial infection after viral pneumonia and hospital-acquired pneumonia

  • Resuscitation fluids

  • Vasopressors and inotropes

  • Sedatives and analgesics

  • Neuromuscular blocking agents

  • Enteral nutrition

Infection control and prevention equipment

Contact isolation

Droplet isolation

Airborne isolation

◆ Gloves—sterile and non-sterile

  • Face shields

  • Goggles

  • Face masks

  • N-95 respirators

  • Powered air purifying respirators

  • HEPA Filters

Specific equipment for supportive care in patients with oxygenation failure

  • High frequency oscillation ventilators

  • ECMO

  • Equipment to support prone patient positioning

Critical care triage

Triage protocols for pandemic situations should only be activated if surge capacity has been maximized across a broad geographic area, calls for aid (personnel, equipment, etc.) have gone out through local, national, and international channels, and there is still a substantial demand-capacity mismatch that will result in some patients being unable to receive usual care [8]‌. Timing of critical care triage is very important—too early results in ‘over-triage’ and waiting too long results in a precipitous decline in the available resources [15]. Equitable distribution based on ethical principles of justice, beneficence, and non-maleficence should drive a triage protocol. Our usual principals of admission to ICU emphasize a ‘first come, first served’ approach. However, triage systems based upon severity of illness scoring systems have been proposed [8]. Such systems underperform when the pandemic population differs substantially from the derivation group, by younger age, or single organ failure in the H1N1 experience for example [15]. Criteria for triaging should be objective, transparent, easy to apply, and ideally flexible enough to allow a scaled ramping up and down as capacity changes.

Education

Simulation training plays a key role in preparation for pandemics, but cannot anticipate or address the nuances of all possible scenarios, cannot reach all staff, and will not replace targeted and specific intra-pandemic training. Training should begin as soon as possible with demonstrations followed by supervised practice. Subjects to be taught will inevitably include pandemic specific medical management, deployment of personal protection techniques, environmental decontamination, handling of laboratory specimens, alert lists, potential triage systems, visitor restrictions, and stress recognition and management, among others [7,8,10,11,14].

Management

Ventilation and oxygenation

Respiratory symptoms associated with severe hypoxaemia are likely to be common during viral respiratory pandemics and will require supportive care with supplemental oxygen and mechanical ventilation. While a review of effective therapy for ARDS is beyond the scope of this chapter, lung-protective ventilation, with judicious application of positive end expiratory pressure and intravenous fluid management should form the mainstay of lung supportive care. Severe ARDS, as seen during SARS and the 2009 influenza H1N1 pandemic will lead to increased frequency of ‘rescue therapies’, such as extracorporeal membrane oxygenation (ECMO), prone positioning, high frequency oscillatory ventilation, and inhaled nitric oxide [3,4,16]. While the role of ECMO, high frequency oscillation (HFO), prone positioning and nitric oxide is still unclear, pandemic-specific characteristics, such as young age and single organ failure may increase the likelihood of clinical benefit among therapies proven, thus far, only to improve oxygenation [3,4,16].

Pharmacotherapy

The SARS outbreak was as a result of a coronavirus that led to rapid development of ARDS and may have had an overall mortality of almost 10% [5,6]. Clinicians used ribavirin, steroids, and interferon alpha during the outbreak [5,17]. Subsequent analysis of all these interventions failed to show survival benefit among patients with SARS [6]‌. So no clear recommendations can be made in regard to the pharmacological treatment options for SARS [6,17]. The 2009 influenza H1N1 pandemic was unique as a severe disease requiring critical care services, which disproportionately affected young, immunologically naïve patients [3,4,15]. In critically-ill patients, the use of neuroaminidase inhibitors (oseltamivir, zamanavir) may have been associated with a lower incidence of death, although true effectiveness is impossible to define outside a properly performed clinical trial [3]. Optimal duration and dose of these therapies is uncertain [3,4,18,19].

There is an extensive prior literature and ongoing debate about the effects of corticosteroids on severe ARDS, and pandemic-associated ARDS. We saw extensive use of corticosteroids during SARS and the 2009 influenza H1N1 outbreak [18]. Although there is suggestive clinical trial data supporting steroid use for severe ARDS, observational studies during the pandemic highlighted worse outcomes among corticosteroid-treated patients. Yet this relationship probably suffers from residual confounding [18]. Currently, there is even less evidence for other agents.

Recent studies have emphasized common bacterial co-infection among patients with severe viral pneumonia [19]. Based on the available literature, early initiation of antibiotics, covering community-acquired organisms and organisms associated with viral infections (e.g. Staphylococcus aureus) are probably a very important aspect of therapy [19].

Establishing the means to rapidly deploy effective immunization to the at-risk population (including health care workers) is cost-effective and should be a key component of any pandemic response.

Research

The SARS epidemic highlighted the difficulties associated with developing and implementing studies during pandemic situations [6]‌. The H1N1 pandemic reaffirmed the need for early clinical and epidemiological data to be developed and implemented in a timely manner to help guide clinical decisions and health policy. During the early phase of the H1N1 (2009) pandemic, a number of critical care groups collaborated with government-affiliated agencies and other funders, and developed sound methodology to study the epidemiology and outcomes of critical illness in pandemic situations [20]. However, clinical trials were still delayed as protocols had not been prepared, regulatory bodies were sometimes slow to assess them, and accruement was limited. In response, the International Forum for Acute Care Trialists (InFACT) [20] evolved, with a vision of improving the quality of care for acute life-threatening illnesses throughout the world, by establishing collaborative networks of critical care societies and research trials groups to develop specific, adaptive studies and trials ahead of subsequent threats. Research preparedness, with protocols prevetted and approved, electronic case report forms and clinical trials databases preconstructed and with internationally harmonized definitions, and placebo/comparator agents well worked out before a pandemic will afford the best chance at early accurate pandemic descriptive and interventional studies [20].

Conclusion

ICUs will play an instrumental part in the care of the sickest patients during a disease outbreak. An appropriate critical care response to disease outbreaks requires preparation for an efficient response, strengthened by regular training of health care staff. The implementation of surge capacity and triage will become important when patient volumes exceed normal limits, and these decisions should always be made based on ethical, humanitarian, and legal principles. Appropriate infection control techniques are critical to saving lives by preventing secondary transmission to health care workers or other patients. Specific anti-viral therapy, antibiotics directed towards probable secondary infections, supportive ventilation and oxygenation, and adherence to multisystem critical care ‘best practices’ will prevent substantial mortality and morbidity, and lessen the pandemic’s impact on global health.

References

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