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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

Lewis Rubinson, MD, PhD; John L. Hick, MD; J. Randall Curtis, MD, MPH, FCCP; Richard D. Branson, MS, RRT; Suzi Burns, RN, MSN, RRT; Michael D. Christian, MD; Asha V. Devereaux, MD, MPH, FCCP; Jeffrey R. Dichter, MD; Daniel Talmor, MD, MPH, FCCP; Brian Erstad, PharmD; Justine Medina, RN, MS and James A. Geiling, MD, FCCP

^* From the University of Washington (Dr. Rubinson), Seattle, WA; Hennepin County Medical Center (Dr. Hick), Minneapolis, MN; Harbor View Medical Center (Dr. Curtis), Seattle, WA; University of Cincinnati (Mr. Branson), Cincinnati, OH; University of Virginia (Ms. Burns), Charlottesville, VA; Mount Sinai Hospital/University Health Network (Dr. Christian), Toronto, ON, Canada; Sharp Coronado Hospital (Dr. Devereaux), Coronado, CA; Presbyterian Hospital (Dr. Dichter), Albuquerque, NM; Beth Israel Deaconess Medical Center (Dr. Talmor), Boston, MA; University of Arizona (Dr. Erstad), Tucson, AZ; American Association of Critical Care Nurses (Ms. Medina), Aliso Viejo, CA; White River Junction VA Medical Center and Dartmouth Medical School (Dr. Geiling), Hanover, NH. A list of Task Force members is given in the ^Appendix.

Correspondence to: Lewis Rubinson, MD, PhD, University of Washington, Harborview Medical Center, Campus Box 359762, 325 Ninth Ave, Seattle, WA 98104; e-mail: rubinson{at}u.washington.edu

	Abstract

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Background: Mass numbers of critically ill disaster victims will stress the abilities of health-care systems to maintain usual critical care services for all in need. To enhance the number of patients who can receive life-sustaining interventions, the Task Force on Mass Critical Care (hereafter termed the Task Force) has suggested a framework for providing limited, essential critical care, termed emergency mass critical care (EMCC). This article suggests medical equipment, concepts to expand treatment spaces, and staffing models for EMCC.

Methods: Consensus suggestions for EMCC were derived from published clinical practice guidelines and medical resource utilization data for the everyday critical care conditions that are anticipated to predominate during mass critical care events. When necessary, expert opinion was used.

Task Force major suggestions: The Task Force makes the following suggestions: (1) one mechanical ventilator that meets specific characteristics, as well as a set of consumable and durable medical equipment, should be provided for each EMCC patient; (2) EMCC should be provided in hospitals or similarly equipped structures; after ICUs, postanesthesia care units, and emergency departments all reach capacity, hospital locations should be repurposed for EMCC in the following order: (A) step-down units and large procedure suites, (B) telemetry units, and (C) hospital wards; and (3) hospitals can extend the provision of critical care using non-critical care personnel via a deliberate model of delegation to match staff competencies with patient needs.

Discussion: By using the Task Force suggestions for adequate supplies of medical equipment, appropriate treatment space, and trained staff, communities may better prepare to deliver augmented essential critical care in response to disasters.

Key Words: disaster medicine • influenza pandemic • mass casualty medical care • medical surge capacity

	Introduction

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The severe acute respiratory syndrome epidemic of 2002–2003, recent natural disasters, burgeoning concern about industrial and intentional catastrophes, and the looming threat of a severe influenza pandemic have stimulated much recent debate about how to care for a surge of critically ill people.^{123456789101112} Still, most countries, including those with widely available critical care services, lack sufficient quantities of specialized staff, medical equipment, and ICU space to provide timely, usual critical care for a large influx of additional patients (see "Definitive Care for the Critically Ill During a Disaster: Current Capabilities and Limitations"). Provision of essential rather than limitless critical care will be needed to allow many additional community members to access key life-sustaining interventions during disasters.

Without pre-event critical care surge planning, the quantities and types of medical resources that remain available will dictate which elements of critical care can be maintained. There is no guarantee that effective critical care interventions will be provided. Alternatively, critical care professionals could decide prior to an event what constitutes essential critical care practices and the associated staffing, medical equipment, and treatment space requirements. Critical care disaster preparedness efforts can then be focused to ensure that these crucial resources remain available in sufficient quantity during disasters in order to maximize delivery of essential critical care.

The Task Force for Mass Critical Care (hereafter referred to as the Task Force) was convened in January 2007 and defined emergency mass critical care (EMCC) as a circumscribed set of key critical care therapeutics and interventions, as well as the necessary supporting medical resources required to maintain continuity of sufficient critical care services during a catastrophe (Table 1 and "Definitive Care for the Critically Ill During a Disaster: A Framework for Optimizing Critical Care Surge Capacity"). The Task Force suggests that hospitals with ICUs plan to provide modified but sufficient critical care for a daily patient census triple their baseline ICU capacity for up to 10 days without adequate external assistance (see "Definitive Care for the Critically Ill During a Disaster: A Framework for Optimizing Critical Care Surge Capacity"). Additional details regarding the Task Force are summarized elsewhere (see "Summary of Suggestions From the Task Force for Mass Critical Care Summit"). This current document suggests quantities of essential medical equipment, treatment space expansion concepts, and staffing models to assist emergency planners, clinical staff, and public health officials to meet these capacity goals.

	Development of Task Force Suggestions for Medical Resources

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Avoiding preparation to increase the availability of key medical resources will profoundly limit the capabilities of hospitals to offer many victims life-sustaining care when needed during a mass critical care event. Nevertheless, expecting all hospitals to stockpile multiples of every conceivable piece of critical care consumable and durable medical equipment for use only during low-frequency/high-consequence events is unrealistic and perhaps even reckless.¹⁴ Optimal critical care disaster preparedness calls for a resource strategy between these two extremes. The limited scope of care suggested for EMCC (see "Definitive Care for the Critically Ill During a Disaster: A Framework for Optimizing Critical Care Surge Capacity") affords the opportunity to construct a more restricted list of medical resources for critical care surge capacity (Tables 234 ). This abridged set of resources is intended to make sufficient critical care surge capability achievable by most communities.

The Task Force assumes durable medical equipment requirements to be one device for each treatment space for the entire 10-day period. To determine the suggested quantities of consumable medical equipment, the Task Force used (when available) published clinical practice guidelines and medical resource consumption data regarding everyday ICU management of common critical care syndromes that are anticipated to be predominant medical conditions during mass critical care events (eg, ARDS and severe sepsis). As a result of the paucity of published medical resource data for these conditions, most of the Task Force suggestions had to be derived empirically from the extensive, multiprofessional expertise of Task Force members in the fields of critical care, the military, and disaster medicine. To account for the impact of patient turnover on required consumable medical equipment, a supply buffer was developed. The premise for this additional quantity of equipment is that not all critically ill disaster victims will require 10 days of critical care; some will improve and no longer require critical care, and others will die. The next patient who is admitted to the same critical care treatment space will then require new consumable medical equipment, and thus the actual consumable equipment requirement will be greater than that calculated for one patient for 10 days. Given the lack of definitive data to estimate the additional equipment necessary to account for patient turnover across the range of plausible mass critical care events, the Task Force suggests that the supply buffer should be an additional 30% of consumables above what one individual patient would require for 10 days (130% of the resource; ie, plan on 1.3 endotracheal tubes per patient). The Task Force considers an additional 30% supply to be within the range of plausible need and still would not add a major financial barrier, which impedes most communities from adhering to the suggestions; 20% or 40% could just as easily be justified by individual communities. The Task Force also recognizes that in catastrophic situations, care processes may by necessity degrade even beyond EMCC standards. For instance, if disposable ventilator circuits become in short supply, clinicians may consider reusing them for subsequent patients after sterilization attempts.

Owing to the broad scope of equipment necessary for EMCC, this article cannot provide comprehensive rationales for every suggested piece of equipment. The Task Force deliberately concentrated on surge positive pressure ventilation (PPV) because of its underrepresentation in the published medical literature, the importance of the topic, and recent calls for this guidance.¹⁸

Mechanical Ventilation: Surge PPV
Suggestion 3.1: EMCC requires one mechanical ventilator per patient concurrently receiving sustained ventilatory support. Several groups¹⁹²⁰ have described use of a single ventilator with a multiple-limb ventilator circuit. While at first glance this strategy is appealing, the research to date has demonstrated only that similar test lungs and pharmacologically paralyzed sheep with normal lungs can be ventilated by this approach. Perhaps this strategy would have utility for ventilating patients with normal lungs (eg, isolated traumatic brain injury) and thereby free additional ventilators for patients with high resistance or low compliance. Extrapolation to EMCC would require pharmacologically paralyzed patients who remain matched for minute ventilation requirements, dynamic airflow resistance, and compliance throughout the duration of ventilation; however, these parameters are likely to vary during the duration of mechanical ventilation, and may even change over a period of minutes (eg, secretions causing increased airflow obstruction). Because the Task Force anticipates that most additional patients requiring mechanical ventilation during a mass critical care event will have severe airflow obstruction or lung injury²¹ and will require days of ventilatory support, the Task Force suggests that each patient should have his or her own mechanical ventilator.

Suggestion 3.2: PPV equipment purchased for surge capacity should at a minimum accomplish the following: (1) be able to oxygenate and ventilate most pediatric and adult patients with either significant airflow obstruction or ARDS; (2) be able to function with low-flow oxygen and without high-pressure medical gas; (3) accurately deliver a prescribed minute ventilation when patients are not breathing spontaneously; and (4) have sufficient alarms to alert the operator to apnea, circuit disconnect, low gas source, low battery, and high peak airway pressures. Manual ventilators (eg, Ambu bags; Ambu; Linthicum, MD) are inexpensive and relatively plentiful and may have short-term applications in disasters.²² Manual ventilators, though, are difficult to use for extended periods of time, especially for patients with significant air flow obstruction or low compliance. Sophisticated mechanical ventilators offer significant advantages over manual ventilators, especially when PPV augmentation will be required for more than several hours. Major benefits include the ability to deliver consistent and appropriate minute ventilation, to conserve oxygen and staff stamina, and (because of alarms that alert staff to unsafe patient-ventilator interactions) to allow health professionals to perform other medical functions, thus reducing the required time at bedside.

Hospitals should plan to provide acceptable surge PPV equipment sufficient to meet their EMCC capacity goal. However, the initial purchase and ongoing maintenance costs will likely prohibit most hospitals from having their own stockpile to meet their entire EMCC capacity goal. Therefore, short-term strategies to augment PPV capacity until equipment from outside agencies arrives are encouraged. Anesthesia machines may be repurposed as ventilators (although some surgeries may have to be deferred), as may noninvasive PPV (NIPPV) equipment capable of providing volume ventilation through an endotracheal tube. These temporary options should not be considered definitive solutions for prolonged, large-scale events, such as an influenza pandemic. At least some anesthesia machines will need to be reassigned for surgeries if the response is longer than several days and there are insufficient quantities of appropriate noninvasive devices at hospitals to handle the quantities of additional patients anticipated for such events.²³ When existing hospital PPV equipment—including repurposed anesthesia machines, noninvasive devices, and sophisticated transport ventilators—is not available in sufficient quantities to meet patient needs, then devices from unaffected hospitals or stockpiled PPV equipment should be requested from local, state, and federal stockpiles via the usual resource request channels.²⁴ For most disasters, outside assistance can be expected. For events involving multiple regions or entire nations, outside assistance may be insufficient to meet the mechanical ventilation needs of a local community.

The Task Force does not suggest that each hospital individually purchase all of the PPV equipment necessary to surge to their EMCC capacity goals. Rather, hospitals should work with their local, regional, and state partners to perform a PPV needs analysis for all plausible mass critical care events, such as a severe influenza pandemic. Hospital PPV equipment together with existing caches, such as the US Centers for Diseases Control and Prevention (CDC) Strategic National Stockpile ventilator inventory,²⁵ should be evaluated to make sure they are sufficient to meet EMCC capacity goals within reasonable time expectations and assuming multiple hospitals concurrently requesting equipment. For these analyses, hospitals are cautioned against relying solely on rental PPV equipment because multiple hospitals within a region are usually dependent on the same several vendors and the overall rental supply is often limited. Additional nonfederal stockpiles of PPV equipment are appealing because the devices would be expected to more reliably arrive in a timely manner. Also these stockpiles will allow for distribution of one or two ventilator models to affected hospitals, as opposed to piecing together a supply of many makes and models, and will increase likelihood that staff will be able to operate the devices and that necessary device-specific ancillary equipment (eg, ventilator circuits) will be available. If regional analyses demonstrate significant PPV gaps and additional metropolitan, intrastate regional, or state caches are considered, Table 2 provides guidance for surge PPV equipment. Equipment characteristics were based on the following: (1) perceived requirement for adequate, sustained mechanical ventilation; (2) demonstrated effectiveness; (3) ease of use; and (4) minimization of purchase, maintenance, and training costs.

Several groups²¹²⁶²⁷ have cautioned against purchasing additional noninvasive ventilation equipment designed primarily for mask ventilation as surge PPV equipment. The Task Force concurs with these cautions and does not propose NIPPV as a principal strategy for managing mass casualty respiratory failure, for the following reasons: the need for experienced users²⁸; requirement of significant initial staff time²⁹; limited benefit and infrequent use in practice for ARDS³⁰³¹³²; and the uncertainty as to whether NIPPV may generate significant respiratory aerosols that would be difficult to scavenge during an epidemic of a respiratory-transmitted pathogen.^33343536

Mechanical ventilators require ancillary equipment to function properly. The Task Force suggests a list of ancillary respiratory equipment (Table 3). Ancillary equipment selection is also based on the same four criteria as for surge PPV. Quantities of consumable equipment were determined from standard practice and expert opinion and adjusted for the consumable equipment supply buffer (refer to prior section). This equipment list was developed as a guide for hospitals and government agencies preparing for EMCC, but it is not intended as a rigid mandate. Individual institutions and regions should modify the list to match their local practices. At the same time, the Task Force cautions that trying to manage patients with less than the recommended equipment may render some elements of EMCC care unsafe or ineffective.

The Task Force wants to focus special attention to the requirement for surge PPV to be able to operate without high-pressure medical gas. High-pressure medical gas, which is required by PPV devices without internal compressors, is provided in hospitals as medical air and oxygen. Many patient locations outside of critical care units do not have all of the equipment necessary to deliver either of the high-pressure medical gases to ventilators. Even if medical air is available, PPV devices whose internal oxygen blenders require consistent high-pressure oxygen will be unable to provide supplemental oxygen to patients in treatment spaces that have only low-flow oxygen regulators. Alternatively, the high-pressure equipment may be present, but provision of sufficient oxygen pressure and flow may be compromised as a result of insufficient oxygen on site (limited liquid oxygen volume or failure of oxygen concentrators), interruption of the main supply line to the hospital, or flow limitation of the oxygen piping system of the entire hospital.

All but the smallest hospitals rely on bulk cryogenic storage or concentrators as the source of oxygen, which is distributed through piping to oxygen stations (also referred to as terminal units) in clinical locations.³⁷³⁸ Bulk liquid oxygen is an efficient way to store the large volume of oxygen used by hospitals. The major vulnerability specific to liquid oxygen is that it is not made at hospitals and therefore requires distribution from manufacturers. Most hospitals have enough liquid oxygen on site to respond to a short-term event without resupply; Charity Hospital in the wake of Hurricane Katrina still had enough liquid oxygen for several additional days at the time of evacuation (Ben Deboisblanc, MD; personal communication; May 2006). Maintaining a medical response, either by hospitals with small oxygen reserves or by most hospitals during a prolonged response, will require resupply of liquid oxygen. Resupply may be unreliable owing to damaged transportation routes or insufficient numbers of available, trained drivers (because of illness or fear) to make oxygen deliveries. Fewer hospitals rely on on-site oxygen concentrators rather than liquid oxygen as their primary gas source. These systems are not dependent on oxygen distribution from off-site manufacturers, but still require a continuous supply of electricity to operate. At most facilities, regardless of their source of oxygen and even with reserve oxygen systems for primary source failure, oxygen intended for the entire facility enters using the same length of pipe.³⁷ If the primary system fails as a result of disruption of this piping connection (eg, earthquake), then the reserve system, if it relies on the same piping external to the hospital, will be ineffectual.

Because of costs and size limitations, piping systems to distribute oxygen throughout the hospital are not designed to provide high-flow oxygen to every oxygen station in the hospital at the same time.³⁹⁴⁰ Instead, "diversity factors" are employed that assume only a certain number of oxygen stations will be operating concurrently at high flow. This has important implications for events when hospitals need to deliver high-flow oxygen from most of their oxygen stations. There may be sufficient bulk oxygen source on site, but the flow of oxygen may become limited in some treatment spaces. For these situations, additional means to deliver oxygen to treatment spaces will be necessary.⁴¹ Compressed oxygen, such as the commonly used E cylinder (644 L) or H cylinder (6,900 L) can meet short-term oxygen needs. However, it is logistically difficult to have enough oxygen for many patients provided by compressed gas cylinders. Each patient who uses 4 L/min of oxygen requires 5,760 L of gaseous oxygen per day, nearly an H cylinder per day. Given cost and storage constraints, most hospitals maintain only enough cylinders to cover short-term disruptions of the bulk liquid systems.

Using small oxygen concentrators is another option. These devices, which provide up to 10 L/min, can bypass the hospital oxygen piping distribution system, and their capability to trans-fill compressed gas cylinders is appealing. Concentrators require a continuous supply of energy and do not directly provide high-pressure oxygen to drive pneumatically driven mechanical ventilators. A third surge oxygen option is use of several hundred liter liquid oxygen containers with a portable liquid oxygen vaporizer.⁴² Mass critical care events may require a patchwork of oxygen alternatives that can be connected to isolated zones of the hospital piping system⁴¹ or can distribute oxygen directly to patient areas in order to augment or back up primary bulk oxygen systems; hospital planners are encouraged to work with personnel who have medical gas expertise, including extensive knowledge of relevant regulations.⁴³⁴⁴ PPV equipment that minimizes oxygen use and that can use different oxygen sources (eg, does not require a constant high-pressure source of oxygen or air) is highly desirable for EMCC.

Non-Respiratory Critical Care Therapeutics and Interventions
Select non-respiratory medical equipment for EMCC is presented in Table 4. This list provides equipment for the essential nonrespiratory critical care interventions, including hemodynamic support, that are suggested for EMCC (see "Definitive Care for the Critically Ill During a Disaster: A Framework for Optimizing Critical Care Surge Capacity"). For article length considerations and to facilitate information dissemination, this list was not intended to be exhaustive. Instead, it highlights types and quantities of key medical equipment (eg, nasogastric tubes) and expects hospitals to consider and plan for associated equipment (eg, tape for securing nasogastric tubes). Equipment not specific to EMCC (eg, linens and bedpans) are not included but must be considered by hospitals for any surge event, not just those requiring EMCC. Regions and individual hospitals are encouraged to identify any additional resources they believe necessary to provide EMCC. This planning would be done best within a regional health-care collaborative group.⁴⁵

Implicit in this list is that EMCC is being performed in adequate medical treatment locations (see "Emergency Mass Critical Care Treatment Space" below). Equipment found in most treatment spaces (eg, hospital beds and staff call systems) is not included in the Table. This document was developed with a specific focus on critical care surge equipment for a severe influenza pandemic. For infection control equipment excluding ventilator circuit filters, readers are encouraged to refer to World Health Organization and US Department of Health and Human Services guidance for H5N1 and pandemic influenza.⁴⁶⁴⁷ Lastly, because the equipment for renal replacement therapy and enteral nutrition are widely variable and these interventions are optional for EMCC, they are not included in Table 4. Institutions and regions should involve health-care professionals with expertise in these two interventions to determine whether these interventions are deemed essential for local EMCC and, if so, to develop equipment and staffing guidance.

EMCC requires a myriad of pharmaceutical agents and related equipment for administering medications. The 2004 Working Group on Emergency Mass Critical Care provided a list of basic medications organized by organ system. Disaster planners and pharmacists should review this information.³ The Task Force did not feel a need to further develop the EMCC pharmaceutical list. The Task Force believes that the most important aspect of pharmaceutical preparedness for EMCC is the active involvement of pharmacists, especially critical care pharmacists, in institutional and regional EMCC and general surge capacity planning.

Suggestion 3.3: To optimize medication availability and safe administration, the Task Force suggests that modified processes of care should be considered prior to an event, such as the following: (1) rules for medication substitutions, (2) rules for safe dose or drug frequency reduction, (3) rules for conversion from parenteral administration to oral/enteral when possible, (4) rules for medication restriction (eg, oseltamavir if in short supply during an influenza pandemic), and (5) guidelines for medication shelf-life extension.

EMCC Treatment Space
Suggestion 3.4: EMCC should occur in hospitals or similarly designed and equipped structures (eg, mobile medical facility designed for critical care delivery, veterinary hospital, or outpatient surgical procedure center). After ICUs, postanesthesia care units, and emergency departments reach capacity, hospital locations for EMCC should be prioritized in the following order: (1) intermediate care units, step-down units, and large procedure suites; (2) telemetry units; and (3) hospital wards.

Suggestion 3.5: Nonmedical facilities should be repurposed for EMCC only if disasters damage regional hospital infrastructure by making hospitals unusable and if immediate evacuation to alternate hospitals is unavailable. ICUs are deliberately designed to optimize critical care.⁴⁸⁴⁹⁵⁰ Critically ill patients have demanding environmental and medical equipment requirements owing to their physiologic fragility, susceptibility to nosocomial infections and pressure ulcers, complex medication regimens, and need for organ-supportive care (eg, mechanical ventilation). In most hospitals, non-ICU patient treatment spaces have patient care layouts and medical equipment that are less optimal for caring for critically ill patients. Studies⁵¹⁵²⁵³ suggest that critically ill patients have better outcomes in ICUs than on other hospital wards. Mass casualty critical care will nevertheless require EMCC to be delivered outside of ICUs, postanesthesia care units, and emergency departments. To provide EMCC as safely as possible in alternate locations, sites should be prioritized by degree of similarity to the environmental and equipment characteristics of ICUs (Fig 1 ).

View larger version (36K): [in this window] [in a new window] [Download PPT slide]   Figure 1.. Initial expansion of critical care treatment space during disasters. Hospital facilities are the preferred location for the provision of critical care during a disaster. Expanding available critical space therefore becomes a priority that requires the repurposing of current bed utilization. The least sick patients (pts) should be discharged or transferred to community care facilities. This has the downstream effect of permitting the movement of intermediate care/telemetry patients to general practice wards and critical care capabilities expanding into IMCU/telemetry space.

For the initial surge, intermediate care units (IMCUs), also called step-down units, should be repurposed first if present (Fig 1). Once the IMCU reaches capacity, patients normally requiring IMCU-level care should be admitted or transferred to hospital wards, which usually provide the next lower level of care. Discharge of general ward patients to home, assisted-living facilities, non-acute nursing facilities, or other community medical surge facilities can allow for enhanced movement of patients from the higher-acuity-level wards to general hospital wards.⁵⁷ To triple the usual ICU capacity of a US hospital, approximately 40% of total hospital rooms are needed for provision of EMCC (ICU beds constitute approximately 13% of US hospital beds).⁵⁸ Half as many hospital beds have been made available within a day of previous disasters.⁵⁹ For events that evolve over several days or weeks, if hospital admissions are prioritized for critically ill people and temporary medical treatment sites are set up to care for less complex patients (eg, those who would normally be awaiting skilled nursing facility placement or home health evaluation or those who are several days from discharge without expectation of clinical worsening), then tripling ICU capacity in terms of treatment space is possible (Fig 2 ). If the mass critical care event is related to an epidemic of a potentially airborne-transmitted pathogen and critically ill patients are feared to be the most likely to transmit the disease, then infection control considerations may warrant prioritizing another hospital ward over those best equipped for critical care. While critical care may need to be delivered on a number of hospital wards, patients with the most complex monitoring or treatment requirements can still be preferentially assigned to traditional ICU locations. A multiprofessional team of critical care health professionals should establish stratified patient selection criteria for placement in the various EMCC sites.

View larger version (35K): [in this window] [in a new window] [Download PPT slide]   Figure 2.. Critical care expansion during sustained catastrophies will require further expansion of critical care capabilities. All remaining IMCU/telemetry patients (from Fig 1) still in the medical ICU will be transferred to general hospital wards. Most, if not all, lower-acuity patients on the wards will also now need to move out of the hospital. Critical care patients will now occupy most of the hospital, including some of the general hospital wards. See Figure 1 legend for expansion of abbreviations.

Some long-term care facilities also may be acceptable sites for EMCC, especially those equipped with hospital beds, bulk oxygen, and piping systems for widespread distribution of medical air, oxygen, and vacuum to patient care sites. As with the deployable facilities, a significant amount of treatment space would be required to justify the effort to provide care outside of traditional hospitals, as additional medical equipment and staff would need to be transferred from hospitals to these facilities. Specialty care and a broader range of laboratory and diagnostic services are more likely to be widely available in hospitals, so traditional hospital inpatient sites should remain the first priority for EMCC until acceptable alternatives are available.

	Staffing

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Original staffing suggestions for EMCC recommended that non-critical care health-care professionals work in collaborative critical care teams to augment staffing.³ The recommendations were based on the following premise: (1) that critical care requires health professionals with critical care experience or comparable experience with unstable patients (eg, anesthesia and emergency department staff); (2) during disasters with delayed external assistance, such specialized staff are likely to be in short supply⁶²⁶³⁶⁴; and (3) other health professionals may be able to assist with augmenting critical care capability. Given the complexity of critical care management, it was suggested that critical care professionals work collaboratively with non-critical care health professionals to optimize capability and outcomes by overseeing critical care components on a broader set of patients than usual, allowing providers with less experience to provide basic nursing and medical care. The 2004 recommendations stressed the need to cross-train non-critical care health professionals for delivery of basic, core critical care medicine. The Task Force endorses this previously suggested collaborative team model of critical care surge staffing.

Staff Prioritization and Augmentation
In staffing for critical care surge, a deliberate model of delegation is desirable. During a disaster, all work usually preformed may not be "essential" but all health-care workers are essential. The goal of the model is to match the caregiver competencies with patient needs. To that end a common-sense version, a plan that acknowledges the scope of practice and experience of various caregivers, should be used to assign caregivers to the patients.

Suggestion 3.6: Principles for staffing models should include the following: (1) patient care assignments for caregivers should be managed by the most experienced clinician available; (2) assignments should be based on staff abilities and experience; (3) delegation of duties that usually lie within the scope of some workers’ practice to different health-care workers may be necessary and appropriate under surge conditions; and (4) systematic efforts to reduce care variability, procedure complications, and errors of omission must be used when possible.

Physicians
The use of specially trained physicians to care for critically ill patients is becoming the norm for ICUs and has been recommended as a model to improve critical care for the future.⁶⁵ Intensivists come from a variety of backgrounds, including internal medicine, subspecialty-trained internists (most commonly pulmonologists, but also cardiologists, nephrologists, and infectious disease specialists), anesthesiologists, emergency medicine physicians, and general or specialty-trained surgeons. During EMCC implementation, all will be called on to provide care for an overwhelming number of critically ill patients.

Intensivist resources are already limited in most facilities,⁶⁶ so an EMCC model relying solely on intensivists for primary physician management would be impractical at most hospitals. Other physicians can assist with the care of critically ill patients. Most physicians’ training includes time in ICUs, and many have even spent several months on critical care services. This previous experience may prove invaluable in a mass care setting.

To enhance the availability of critical care physicians to supervise care of many additional critically ill patients and to be immediately present at the bedside of unstable patients, willing nonintensivists should be encouraged to participate in critical care teams. Collaborative teams of nonintensivists and intensivists can be designed similarly to physician ICU teams used by most critical care training programs, thus ensuring a strong clinician presence in all areas providing EMCC. The level of independence of nonintensivists should be commensurate with their recent critical care experience. Availability of specialist physicians to participate will be situation dependent. Willing general and subspecialty internists and pediatricians, hospitalists, anesthesiologists, surgeons, emergency physicians, and obstetricians could be assigned to care for up to six critically ill patients each, with intensivists overseeing four to eight of these nonintensivist clinicians (up to 48 patients, depending on their experience). The expansion of physician services may be submaximal early in the scenario until the less-experienced nonintensivists develop the competence and confidence to care for these patients with increasing independence.

Registered Nurses
Those most experienced in the charge nurse role should be identified because they are likely to be the best prepared to quickly match patient needs and caregiver capabilities. Critical care charge nurses are expert at assigning patient beds based on acuity and anticipating abilities of nurses based on experience level. The charge nurse could assign critical care nurses to oversee a deliberately constructed "pod" of patients and mentor non-critical care caregivers assigned to the pod. The charge nurse would assign patients and caregivers to pods but would then rely on the critical care nurses of the pod to assign specific patients to non-critical care nurses in his/her group. The critical care nurses would care for the most challenging patients and be available to assist the non-critical care nurses as needed. Health-care workers without a nursing background could assist with general activities that fall under the purview of nursing responsibilities (eg, patient turning, bathing, vital sign monitoring) but which not only nurses can provide.

Another option would be to assign critical care nurses to all patients while other health-care personnel would be assigned to deliver specific care functions for a group of patients rather than providing a broad range of critical care services for one or several patients. Non-critical care nurses and pharmacists could be responsible for medication delivery; and paramedics, if available, could be assigned to airway maintenance. A hybrid of the "pod" and "functional" options could also be used. Health-care workers with less specific critical care functional expertise but broad health-care knowledge (eg, physical therapists, social workers, nutrition specialists, occupational therapists) can assist nurses with general patient care, and those with "functional" expertise can provide such services. No matter what option used, the critical care charge nurse will provide oversight and work closely with the rest of the critical care team overseeing care management.

Caregivers assisting nurses at the bedside must have a core set of competencies in order to not only provide quality care, but also protect themselves and others. The skill set requires at a minimum the following: (1) infection control practices; (2) physical care activities (eg, patient turning and cleaning); (3) suctioning and artificial airway maintenance; (4) vital signs and monitoring equipment; (5) Foley catheter care and management of bodily wastes; and (6) delivery of medications and nutrition (when applicable) through enteral tubes and use of IV pumps (if available).

Respiratory Therapists
Staffing of respiratory therapists in the ICU can be accomplished based on a model that combines patient severity of illness along with required respiratory care procedures.⁶⁷ As an example of time and skill needs, the American Association for Respiratory Care Uniform Reporting Manual details the time required for care rendered by respiratory therapists, from monitoring the mechanically ventilated patient (often referred to as the patient ventilator system check) to delivery of a metered-dose inhaler.⁶⁸ Under normal circumstances, one respiratory therapist routinely cares for four to six ICU patients receiving mechanical ventilation. This care includes evaluation of patient/ventilator interaction, assessment for weaning, airway care, delivery of inhaled medications, blood sampling for blood gas analysis, and therapy for secretion mobilization.

In a scenario where nearly all of the additional patients have severe respiratory failure, several staffing models are possible. The first reduces the intensity of care and at the same time increases the number of patients receiving mechanical ventilation per respiratory therapist to eight or nine. Under these circumstances, therapy would be triaged and the less crucial care processes omitted by necessity. If this strategy is still insufficient to meet need, a critical care respiratory therapist could supervise one to three non-critical care respiratory therapists (RTs). The critical care RT should perform the more complex tasks and be available to supervise the non-critical care RT staff. This supervision will be most needed when the staff is first undertaking simpler tasks, including suctioning of the airway, delivery of aerosolized bronchodilators, and circuit maintenance; after they are observed to competently perform the tasks, the intensity of supervision can be decreased. This model would allow one critical care RT and one non-critical care RT to care for perhaps 12 to 14 patients.

If need is still unmet, non-respiratory care allied health professionals (eg, occupational therapists, physical therapists) could perform such tasks as airway suctioning, oxygen saturation checks, or metered-dose inhaler administration. This approach has been suggested and even underwent initial evaluation by University of Colorado investigators.⁶⁹ Their model uses a digital video disk to deliver just-in-time training to the recruited non-respiratory health-care workers. This strategy is attractive because it allows for drawing staff from a larger pool of available candidates, and theoretically it would not require recurrent training, which is difficult to sustain for large numbers of health-care workers. Of course, a better option would be to cross-train allied health-care workers recurrently with the materials, and then use the digital video disk also as a refresher during the disaster response. Whether this just-in-time strategy alone is effective at preparing staff to competently perform basic airway care procedures, especially during outbreaks of respiratory-transmitted pathogens, requires further investigation.

Pharmacists
Critical care-trained pharmacists will be in short supply; in many institutions, pharmacy staffing does not provide for dedicated ICU support during usual operations. Shifting an emphasis to EMCC may therefore require repurposing of general pharmacy staff.

The two-tiered approach may be applied to these professionals as well. Critical care-trained pharmacists would oversee pharmacists inexperienced with the critical care setting in such an approach, which could also include use of pharmacy technicians. This approach would allow concentration of support and expertise in the critical care area. In addition, pharmacy support of critical care requires frequent reassessment of drugs in the main pharmacy to ensure smooth delivery of medications along the supply chain. Therefore, pharmacists from all health-system pharmacies in the same geographic location should work together, ideally in coordination with regional health emergency planners, to efficiently redistribute scarce pharmaceutical resources when possible.

All of these staffing models assume that reassigning non-critical care health professionals to assist with critical care will benefit additional critically ill patients. However, staffing in other areas may suffer as a result of these strategies. Critical care requires fewer patients per staff member. More total staff will therefore be necessary to staff the entire hospital when critical care is expanding to nontraditional critical care treatment areas. Staffing for EMCC could increase the number of patients per available staff member for non-critically ill patients if EMCC staffing goes unchecked. The allocation of staff for non-critical care and EMCC services must be dynamic and be matched to the circumstances of the disaster to ensure that the fewest patients are harmed by staffing shortages.

	Immediate Challenges To Implementing EMCC

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The Task Force is the second large North American effort to issue suggestions for mass casualty critical care. The concepts for augmenting critical care have become increasingly mature over the past decade, but their impact on local hospital preparedness efforts is unknown and implementation is likely limited. EMCC has been developed by senior, experienced critical care and disaster medicine experts, but the suggestions remain untested for civilian disasters in countries with modern health-care systems. The lack of evidence for EMCC as a guide for preparedness and response may reduce acceptance by clinicians.⁷⁰

Many reimbursement, regulatory, and liability questions remain unanswered. Clinicians and hospitals generally want to assist with disaster preparedness and response; nevertheless, perceived risk of adverse action for deliberately modifying processes of care may make many shy away from planning for EMCC. A core Western societal expectation of health care is the nearly limitless provision of critical care to those who need and want it; EMCC necessitates significant deviation from this expectation. Emergency powers or legislative efforts must therefore provide indemnity to health professionals following EMCC principles in good faith. Policymakers must ensure that EMCC-relevant issues are prioritized for legislative consideration.

EMCC was developed by professionals committed to improving medical outcomes for our communities during disasters. Despite best intentions, EMCC has essentially been conceived of and modified in forums devoid of nonprofessionals. EMCC and its underlying ethical and resource assumptions must be brought to community discussions for evaluation and modification so that it can be improved by incorporating additional perspectives and ideas. These efforts will be necessary for community support and acceptance, which will be paramount for EMCC implementation during a disaster.

EMCC requires training of staff, but training health-care workers in unfamiliar procedures and processes for infrequent events is fraught with difficulty. Health-care professionals have numerous training mandates, and it will be difficult to make EMCC training an ongoing priority. Within the realities of competing training obligations, strategies must be developed to still provide acceptable levels of training for EMCC. These strategies must take into consideration the expected attrition of knowledge and competency resulting from disuse of skills. Strategies must also anticipate the need to incorporate periodically updated EMCC recommendations.

Despite these challenges, mass critical care events could happen tomorrow or even today. We cannot wait to develop perfect surge strategies because the first time the modern North American health-care system faces mass critical care may prove catastrophic. We must be prepared to implement surge strategies based on contemporary knowledge, experience, and expert opinion.

	Appendix

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Task Force Members in Alphabetical Order
Capt. Dennis Amundson, MD, USN, San Diego, CA; Capt. Michael B. Anderson, RN, MHA, CNAA, Department of Homeland Security, Washington, DC; Robert Balk, MD, Rush University Medical Center, Chicago, IL; Tom Baudendistel, MD, California Pacific Medical Center, San Francisco, CA; Ken Berkowitz, MD, VHA National Center For Ethics in Health Care, New York, NY; Michael Bourisaw, BS (Steering Committee), American College of Chest Physicians, Northbrook, IL; Dana Braner, MD, Doernbecher Children’s Hospital, Portland, OR; Suzanne Burns, RN, MSN, RRT, University of Virginia Health System, Charlottesville, VA; Michael D. Christian, MD, FRCPC (Steering Committee), University of Toronto, Toronto, ON, Canada; J. Randall Curtis, MD, MPH, Harborview Medical Center, Seattle, WA; Asha Devereaux, MD (Steering Committee), Sharp Coronado Hospital, San Diego, CA; Jeffery Dichter, MD (Steering Committee), Presbyterian Hospital, Albuquerque, NM; Nancy Dubler, LLB (Steering Committee), Montefiore Medical Center, Bronx, NY; Brian Erstad, PharmD (Steering Committee), University of Arizona Medical Center, Tucson, AZ; J. Christopher Farmer, MD, Mayo School of Graduate Medical Education, Rochester, MN; James Geiling, MD (Steering Committee), VA Medical Center, White River Junction, VT; Dan Hanfling, MD, Inova Fairfax Hospital, Falls Church, VA; John Hick, MD (Steering Committee), Hennepin County Medical Center, Minneapolis, MN; Capt. Ann Knebel, RN, DNSc, Department of Health and Human Services, Washington, DC; John Krohmer, MD, Department of Homeland Security, Washington, DC; Capt. Deborah Levy, PhD, MPH (Steering Committee), Centers for Disease Control and Prevention, Atlanta, GA; Henry Masur, MD, National Institutes of Health, Bethesda, MD; Justine Medina RN, MS (Steering Committee), American Association of Critical Care Nursing, Aliso Viejo, CA; Nicki Pesik, MD (Steering Committee), Centers for Disease Control and Prevention, Atlanta, GA; Jim Pile, MD, The Cleveland Clinic, Cleveland, OH; Tia Powell, MD, New York State Task Force on Life and the Law, New York, NY; Lewis Rubinson, MD, PhD (Steering Committee), Harborview Medical Center, Seattle, WA; Christian Sandrock, MD, MPH, University of California-Davis, Davis, CA; Richard Serino, BS, Boston Emergency Medical Services, Boston, MA; Lewis Soloff, MD, New York City Department of Health and Mental Hygiene, New York, NY; Daniel Talmor, MD, MPH, Beth Israel Deaconess Medical Center, Boston, MA; Alvin Thomas Jr, MD, Howard University Hospital, Washington, DC; Richard Waldhorn, MD, University of Pittsburgh Medical Center, Baltimore, MD; Mark Woodhead, MD, Guidelines Director, European Respiratory Society; Robert Wise, MD, The Joint Commission, Chicago, IL; Randy Wax, MD, Mount Sinai Hospital, Toronto, ON, Canada; Kevin Yeskey, MD (Steering Committee), Department of Health and Human Services, Washington, DC.

	Footnotes

The views expressed in this article do not represent official positions of the Department of Veterans Affairs.

During the period of the project, Dr. Rubinson initially received partial salary support from a contract with the Strategic National Stockpile program at the CDC Coordinating Office for Terrorism and Preparedness and Emergency Response. He then received full salary support through an Interagency Position Agreement at the CDC Division of Healthcare Quality Promotion. The findings and conclusions in this manuscript are those of the author and do not necessarily represent the views of the CDC. The other authors have no conflicts of interest to disclose.

Received for publication November 4, 2007. Accepted for publication March 3, 2008.

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