Chapter 18 Critical Care in Public Health Emergencies
Basic Concepts
National Response Framework and Incident Command System
Responses to major public health emergencies are organized within a National Response Framework, as outlined by the federal Department of Homeland Security.1 Emergency responses are always coordinated at the most local jurisdictional level possible, usually at the city or county level. Responses to larger disasters need support from adjacent counties, the state, and sometimes from the federal level. The Hospital Emergency Incident Command System (HEICS)2 provides a leadership framework within and among organizations responding to an emergency. HEICS emphasizes flexibility for any type of event, scalability to the size of the event, clear lines of authority, and consistent communications. Disaster plans at every hospital incorporate HEICS principles.
Ordinary Surge and Mass Critical Care
Critical care responses to PHEs are scaled according to the size and severity of the emergency (Table 18-1).3–5 Responses are categorized as (1) ordinary surge, (2) temporary reactive mass critical care, and (3) sustained mass critical care. For a sudden-impact event involving modest (10% to 15%) increases above usual peak hospital capacity at one or more local hospitals, ordinary surge methods would suffice to provide normal standards of critical care to all those who need it. Ordinary critical care surge needs are met by canceling elective admissions, quickly discharging all patients who can safely leave the ICU, mobilizing staff, and adding beds, as feasible. Most hospitals have occasional experience with ordinary critical care surge responses.
No. of Patients | Type of Event and Response | Authority to Implement Response |
---|---|---|
Modest increase (10%-20%) above usual peak capacity | Decision making by usual clinical leaders | |
Up to three times usual peak capacity | Gradual onset, sustained PHE with adequate preparation, resources meet needs, usual standards of care Sudden-impact PHE, needs exceed resources, temporary “reactive” mass critical care, crisis standards of care | |
Exceeds three times usual peak capacity | Needs overwhelm resources despite mass critical care, mass critical care, and rationing, crisis and palliative standards of care | Legal basis and liability protections are ambiguous38 |
PHE, Public health emergency.
Data from Devereaux A, Christian MD, Dichter JR, et al: Summary of suggestions from the Task Force for Mass Critical Care, Chest 133:1S-66S, 2008.
Mass critical care approaches would be implemented when a very large PHE threatens to overwhelm critical care resources. It is recommended that mass critical care personnel be able to care for up to three times the usual number of critically ill patients for up to 10 days without outside help. In these circumstances, population-based goals would attempt to maximize numbers of survivors by providing immediate lifesaving interventions to all persons who need them and delaying or forgoing other interventions. Thus standards of mass critical care are not equivalent to normal circumstances and should be considered to be crisis standards of care. Sudden impact events that stress the resources of a community may require the implementation of temporary reactive mass critical care. Experience with a massive surge of critically injured patients after a major fire demonstrated the satisfactory outcomes that are possible as a result of well-organized responses that included elements of the temporary reactive mass critical care approach.6 A sustained PHE that exceeds resources over a wide area may require the sustained implementation of mass critical care. No historical precedents exist for sustained mass critical care.
In many states existing laws would permit mass critical care to be implemented on a temporary reactive basis under the authority of an individual hospital’s incident commander for a sudden impact event that threatens to overwhelm the resources of a hospital. PHE powers are defined on a state-by-state basis.7 Where laws exist to authorize sustained mass critical care, this authority is generally at the level of a state public health official.
Pediatric Critical Care Needs and Resources in a Public Health Emergency
If a PHE affected persons of all ages equally, then children aged 0 to 14 years would account for 20% of the patients and children aged 0 to 19 years would account for 28% of the patients.8 Younger patients may be more vulnerable to infections, dehydration, toxins, and trauma and are less able to protect themselves in a dangerous environment. Thus children may be overrepresented in a patient population during a PHE. Accidents involving a child-specific activity or terrorism intentionally targeting children may result in a patient population predominantly made up of children. Some planning scenarios considered by the Department of Homeland Security exceed the entire national critical care capacity.3
Survival rates from high-risk pediatric conditions tend to be better when children receive care at pediatric hospitals.9–12 The younger the patient, the more age-specific are the treatment requirements. A national survey estimated a pediatric ICU (PICU) peak capacity of 54 beds per million pediatric population.13 Because normal PICU occupancy exceeds 50%, fewer than 30 vacant PICU beds per million age-specific population are generally available in a region. Because each region may only be served by a single or a few pediatric hospitals, events that disable a pediatric hospital may disproportionately degrade regional pediatric care.
Quantitative models indicate that survival in a PHE would be better if pediatric patient surge is distributed to pediatric beds throughout a region, rather than overloading facilities near the scene of an emergency.14 Appropriate utilization of pediatric hospitals would be promoted by clear identification of pediatric hospitals.15,16 Unfortunately, control of patient distribution may be impossible in a PHE.17 As a result, all hospitals must be prepared to care for some children.18 Even if pediatric regional resources are used optimally, hospital vacancies to accommodate pediatric surges are empirically much more limited than for adult patients.19 Whether or not patients are distributed optimally to hospitals, outcomes from a hypothetical large PHE are likely to be better with mass critical care approaches.14,20
Emergency Department Phase
Triage
It is beyond the scope of this chapter to advocate one triage tool in preference to others. No single tool is always rapid, completely accurate, appropriate to all ages and disorders, and already familiar to all providers.21 Staff should be familiar with the physiological triage tool in use locally.